-------
3 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IV
345 COURTLAND STREET
ATLANTA. GEORGIA 30385
September 10, 1981
KEF: 4SA-EIS
TO: ALL INTERESTED GOVERNMENTAL AGENCIES, PUBLIC GROUPS, AND
CONCERNED INDIVIDUALS
The Draft Environmental Impact Statement for the Mobil Chemical
Company South Fort Meade Phosphate Mine and Beneficiation Plant
is enclosed for your review. This document has been prepared
pursuant to Section 102(2)(c) of the National Environmental
Policy Act (NEPA) (Public Law 91-190) and applicable EPA
regulations at 40 CFR Part 6.9. A Supplemental Information
Document has also been prepared which contains the supporting
data related to the EIS. While the draft EIS is a complete
document, much of the technical detail has been presented in
the Supplemental Information Document (SID) to reduce the
length of the DEIS, to make the DEIS more analytical than
encyclopedic, and to make the DEIS more understandable to the
non-technical public. The Draft EIS and the SID may be
reviewed at the following locations:
Lakeland Public Library, Lakeland, Florida
Bartow Public Library, Bartow, Florida
Ausley Memorial Library, Wauchula, Florida
Selby Public Library, Sarasota, Florida
Manatee County Library System, Bradenton, Florida
Tajnpa-flillsborough County Public Library/ Tampa, Florida
A public hearing to discuss this project has been scheduled for
October 20, 1981, at 7:30 p.m. in the Bartow County Civic
Center, located at 2250 Floral Avenue, Bartow, Florida.
Persons may begin to register at 7:00 p.m.
Persons wishing to make comments should attend and speak at the
hearing. A verbatim transcript will be made of this public
hearing. The hearing chairman may request that lengthy or
technically complex statements be summarized and that, to
ensure accuracy of the record, such statements be submitted in
writing to:
Ms. A. Jean Tolman
EIS Project Officer
Environmental Protection Agency
Region IV
345 Courtland Street, N.E.
Atlanta, Georgia 30365
-------
-2-
The hearing record will remain open and additional written
comments may be submitted through November 2, 1981. Such
additional comments will be considered as if they had been
presented at the public hearing.
Recipients of this document should be aware that EPA will not
reprint the material contained in the DEIS for the Final EIS.
The Final EIS will consist of the Agency's statement of
findings, any pertinent additional information or evaluations
developed since publication of the Draft EIS, comments on the
project and the Agency responses, and the transcript of the
public hearing.
Please bring this notice to the attention of all persons who
may be interested in this matter.
Sincerely yours,
Charles R. Jeter
Regional Administrator
Enclosure: DEIS
-------
Repository Material
DRAFT
ENVIRON
for
Proposed Issuance of a New Source National
Pollutant Discharge Elimination System Permit
(0
.SJ
CO
"=~ o
CD O
:> O
CD
-= X .Ł Q
e-^
co <
rSO.
CTLU
13
CD
X
O co
r- CO
n CM
to
Mobil Chemical Company
South Fort Meade Mine
Polk County, Florida
prepared by:
U.S. Environmental Protection Agency
Region IV, Atlanta, Georgia 30365
cooperating agencies:
U.S. Army Corps of Engineers
Jacksonville District
Jacksonville, Florida 32201
U.S. Department of the Interior
Bureau of Land Management
Eastern States Office
Alexandria, Virginia 22304
Mobil Chemical Company has proposed an open pit phosphate mine,
beneficiation plant and transshipment facility on a 16,288-acre
site in southern Polk County, Florida. Mining would involve
15,194 acres, all of which would be reclaimed, and would
produce 77 million tons of phosphate products over a 25-year
period. The EIS examines alternatives, impacts and mitigative
measures related to air, geology, radiation, groundwater,
ecology and other natural and cultural systems.
Comments will be received through November 2, 1981. Comments or
inquiries should be directed to:
A. Jean Tolman, EIS Project Officer
U.S. Environmental Protection Agency - Region IV
345 Courtland Street, N.E.
Atlanta, Georgia 30365
(404) 881-7458
approved by:
August 31, 1981
Char
Regi
R. Jeter
Administrator
Date
-------
Summary Sheet
for
Environmental Impact Statement
Mobil Chemical Company
South Fort Meade Phosphate Mine
(X) Draft
( ) Final
U.S. Environmental Protection Agency, Region IV
345 Courtland Street, N.E.
Atlanta, Georgia 30365
1. Type of Action: Administrative (X) Legislative ( )
2. Description of Action:
Mobil Chemical Company (Mobil) is proposing to construct and
operate a phosphate mine and beneficiation plant in Polk
County, Florida. The EPA Region IV Administrator has declared
the proposed facilities to be a new source as defined in
Section 306 of the Federal Clean Water Act.
In compliance with its responsibility under the National
Environmental Policy Act (NEPA) of 1969, EPA Region IV has
determined that the issuance of a new source National Pollutant
Discharge Elimination System (NPDES) permit for the proposed
mining and beneficiation facility (the South Fort Meade Mine)
would constitute a major Federal action significantly affecting
the quality of the human environment. Therefore, this
Environmental Impact Statement has been prepared in accordance
with the requirements of NEPA and EPA regulations at 40 CFR
Part 6. EPA will issue, issue with conditions, or deny
issuance of the NPDES permit based on the review of the permit
application and the findings of this EIS.
The applicant's proposed mining operation, the South Fort Meade
Mine, would produce 77 million tons of wet phosphate rock over
the 25-year life of the mine. A total of 15,194 acres of the
16,288-acre tract would be disturbed during mining. The mine
would be designed to produce approximately 3.4 million
S-l
-------
tons of phosphate rock annually and would be developed in two
phases. Phase I is scheduled to start up in 1984 following a
21-month construction period. Phase I operations, with an
estimated capacity of 1.7 million tons per year/ would include
one dragline and an associated beneficiation plant. The start
up of Phase II is planned for 1987 following a similar 21-month
construction interval. Facilities comparable to Phase I would
be developed in Phase II, increasing production capacity to 3.4
million tons per year.
Equipment and procedures similar to those presently used in
Mobil's two Florida phosphate mines are proposed for the new
facility. Land clearing would involve harvesting or burning
the vegetation on 50-acre parcels in advance of the mining
operation. When in full production, two large walking
draglines would operate simultaneously, mining and extracting
phosphate from separate areas. Ore would be slurried and
hydraulically transported in pipelines to the beneficiation
plant for washing to separate pebble product, clay and fines,
and for flotation to recover additional phosphate product. Wet
rock would be stored in on-site stockpiles or loaded directly
onto railroad cars for transport to Mobil's existing
rock-drying facilities in Nichols, Florida.
Waste clay and sand tailings from the beneficiation plant would
be redeposited on the property in clay impoundment areas and
sand tailings backfill areas. Mobil's proposed action includes
utilizing the conventional clay settling technique for waste
disposal and reclamation. The initial waste clay settling
areas would be built on unmined ground with dikes constructed
of overburden material. These settling areas, totaling 1,320
acres, would hold the waste clays generated during the first
four years of mining. All other waste disposal areas would be
constructed on mined land. The waste disposal plan proposed by
Mobil calls for 8,170 acres of above-grade clay settling areas,
1,513 acres of below-grade clay settling areas, 5,034 acres of
below-grade sand tailings fill areas with overburden cap, and
308 acres of overburden fill areas. Sand tailings would be
used to cap 1,489 acres of above-grade clay settling areas.
Water uses and estimated flow requirements for the South Fort
Meade Mine are identified as follows: slurry water for
slurrying and transporting the ore from the mining area to the
beneficiation plant (27.0 mgd), seal water for transfer pumps
(0.691 mgd), washing/dilution water for the washing facilities
(52.0 mgd), rinsing water for the feed preparation process
(38.0 mgd), process water for flotation (55.9 mgd), and
miscellaneous potable water (0.022 mgd). Most water required
would be supplied from the recirculation system (157.2 mgd).
Groundwater would be used to supply water to the flotation
process (12.3 mgd) and for makeup water (3.4 mgd), pump seal
water (0.691 mgd) and potable water (0.022 mgd). The total
consumptive use of groundwater is projected to be 16.413 mgd.
S-2
-------
Approximately seven percent of the site (1,094 acres) would not
be disturbed by the proposed mining operation. These
undisturbed areas include 111 acres of freshwater swamp, 21
acres of freshwater marsh, 3 acres of surface water (ponds),
664 acres of upland hardwood forest, 182 acres of cutover
forest, 108 acres of improved pasture and 5 acres of upland
mixed forest.
The mined areas would be used for waste disposal, with
sequential reclamation following completion of the waste
disposal activities in each disposal area. The entire
reclamation program would be completed 10 years after mining
has ceased (mine year 35). Mobil's proposed plan provides for
the reclamation of approximately 60,000 linear feet of stream
channels and 1,912 acres of wetlands on the site. The
reclaimed stream channels would replace the disturbed
tributaries of the Peace River and Bowlegs Creek. The
reclaimed site would contain 11,521 acres of improved pasture,
182 acres of cutover flatwoods, 664 acres of upland hardwood
forest, 1,276 acres of upland mixed forest, 453 acres of
planted pine, 3 acres of surface water areas (ponds), 277 acres
of forested stream channel, 589 acres of freshwater swamp, and
1,323 acres of freshwater marsh.
3. Alternatives Considered;
Mobil's proposed mining and beneficiation operation is
comprised of a number of individual mining subsystems that,
when combined, provide a total project capable of satisfying
Mobil's objectives. The identifiable subsystems included in
the Mobil project are as follows:
Mining Method
Matrix Transfer
Matrix Processing
Haste Disposal
Reclamation
Water Sources
Plant Siting
Water Discharge
Product Transport
Various methods (i.e., alternatives) are available to satisfy
the objectives of each of these subsystems. The subsystems,
objectives and alternatives are identified in the following
chart, and a brief description of each alternative is presented
in the succeeding paragraphs.
S-3
-------
Mining
Subsystem
Objective
Alternatives
Considered
Mining Method
Matrix Transfer
Processing
Waste Disposal
Reclamation
Water Sources
Plant Siting
Water Discharge
Product
Transport
Remove overburden and
deliver matrix to a
transport system.
Transport matrix from
the mine to the bene-
ficiation plant.
Process the matrix to
separate the phosphate
rock product from the
waste sand and clay.
Dispose of the waste
sand and clay generated
by matrix processing.
Return the mined site to
unrestricted land use
potential.
Provide a continuous
source of fresh water
(about 16 mgd) for use
in matrix processing and
as makeup for losses in
the recirculation system.
Provide location which
conserves energy and
avoids environmentally
sensitive areas.
Provide location for
clear water pool
discharge.
Move wet rock to exist-
ing drying facilities.
Dragline*
Bucket Wheel
Dredge
Pipeline*
Conveyor Belt
Truck
Conventional
Beneficiation*
Dry Separation
Conventional Clay
Settling Case*
Sand/Clay Cap Case
Sand/Clay Mix Case
Overburden Mix Case
Conventional Plan*
Sand/Clay Cap Plan
Sand/Clay Mix Plan
Overburden Mix Plan
Groundwater*
Surface Water
Gilshey Branch
Site*
Other On-Site
Locations
Peace River*
Bowlegs Creek
Railroad*
Truck
* Mobil's proposed action
S-4
-------
Mining Method
Dragline Mining; Mobil proposes to use two 45-cubic yard
draglinesfor removing the overburden and mining the phosphate
matrix. Both draglines would operate independently, removing
overburden and matrix in two separate mining areas. This is
the conventional mining method used by the Florida phosphate
industry.
Bucket Wheel; A bucket wheel excavator has a large rotating
wheel with fixed buckets attached on its periphery. The bucket
wheel excavator would excavate material and discharge it onto
an associated conveyor belt system. Four bucket wheel
excavators would be required for the proposed mine operation;
two of the units would remove overburden while the other two
units mined the matrix.
Dredge: The dredge unit consists of equipment mounted on a
barge for floating and moving over the material to be
excavated. The cutterhead dredge, considered the dredge unit
best suited for mining phosphate in the central Florida area,
would excavate and pump materials from beneath the water to the
surface via a suction pipe. The South Fort Meade site would
require two cutterhead dredge units to remove overburden and
mine the matrix.
Matrix Transfer
Pipeline; The mined ore would be dumped by the dragline into a
slurry pit for disaggregation. Recirculation water (27 mgd)
would be directed by hydraulic guns to break up the material
and slurry the matrix to a pumpable mixture. Each mining
operation would have a separate slurry system with booster
pumps to deliver the slurry to the plant. This is the
conventional matrix transfer method used in the Florida
phosphate industry.
Conveyor Belt; A conveyor belt system would begin at the field
feed hopper. Ore would have to be transported from the mine
area to the feed hopper. From the hopper, the ore would be
placed on the conveyor belt to be transported to the
beneficiation plant. Two independent 36-inch conveyor systems
would be required to transfer the ore from the two mining areas
to the beneficiation plant.
Truck; Matrix transfer by diesel engine truck could be
accomplished during Phase I with 25-ton capacity trucks making
820 round trips per day. During Phase II, 1,640 truck trips
per day would be necessary using trucks with a 25-ton capacity.
S-5
-------
Processing
Conventional Beneficiation: Conventional beneficiation
operations at the mine would include washing, feed preparation
and flotation, each with the purpose of separating phosphate
rock from the associated organics and gangue minerals
(limestone cobbles, quartz sand and a mixture of clay
minerals). This is the only matrix processing method used in
the Florida phosphate industry today.
Dry Separation; Dry separation is a process that involves
drying, crushing and sizing. After being dried with a rotary
kiln and crushed with a hammermill, the matrix would be
processed through several stages of air separation to separate
the pebble product from the finer materials. Additional
phosphate product would then be separated from the remaining
material by an electrostatic separator.
Waste Disposal
Conventional Clay Settling Case; Mobil proposes to use the
conventional method of waste disposal as currently practiced at
their existing mining operations in central Florida. The
conventional plan calls for the separate disposal of sand
tailings and waste clay. The sand tailings would principally
be used to backfill mined areas (5,034 acres) and as fill in
dike construction for clay impoundment areas. Waste clays
would be contained behind earthen dams to be constructed on
natural ground (1,320 acres) and in mined areas (8,363 acres).
A flow-through settling technique is commonly used with
conventional clay settling and would be implemented at the
South Fort Meade Mine. This technique is generally utilized
for clay settling basins that are located adjacent to each
other. The procedure consists of introducing the waste clay
stream into a series of clay settling basins instead of a
single basin, with all connected basins remaining active until
the last basin is filled and inactivated. The purpose of the
flow-through technique is to achieve improved water
clarification, clay compaction, and water management. Average
dike height for this waste disposal case would be 38.7 teet
above grade.
Sand/Clay Cap Case; The sand/clay cap case would have
above-grade clay settling basin configurations similar to the
conventional case; however, flow-through settling would not be
used with the sand/clay cap disposal method. A five foot thick
sand/clay cap (sand to clay ratio of 4;1) would be placed on
top of the clay settling areas (7,580 acres). In order to
place the sand/clay cap over the settling areas in a timely
fashion, the basins would be taken out of service after the
initial fill and actively dewatered to develop a crust. The
S-6
-------
average dike height for this case would be 36.7 feet. This
waste disposal case also calls for 1,513 acres of below-grade
clay settling basins partially capped with overburden, 590
acres of above-grade clay settling basins capped with
overburden, 5/079 acres of sand tailings fill areas capped with
overburden, and 308 acres of overburden fill areas.
Sand/Clay Mix Case; The sand/clay mix waste disposal method
wouldinvolvemixing gravity-thickened clays with dewatered
sand tailings and depositing the mixture in mined areas for
consolidation and stabilization. The clays would be pumped
from the settling/thickening areas to the mix and disposal
sites. Sand to clay ratios of approximately 2:1 have been
shown in experimental studies to be the minimum acceptable for
achieving significant consolidation benefits. The high clay
content and correspondingly low proportion of sand in the South
Fort Meade Mine matrix preclude the use of sand/clay mix waste
disposal techniques for the entire site. A combination of
sand/clay mix areas (3,512 acres), clay settling areas with a
2:1 sand/clay cap (3,185 acres), graded spoil and overburden
fill areas (1,571 acres), sand tailings fill areas (3,020
acres) and conventional clay settling areas (3,737 acres) would
have to be utilized to dispose of the wastes. The average dike
height for this case would be 35 feet.
Overburden/Clay Mix Case: Since sufficient sand tailings are
not available from the matrix to accomplish a 2:1 sand/clay mix
over the entire site, overburden sand could be used as an
additional source of sand to mix with the waste clay. The
overburden would be slurried and pumped to a field washer for
screening and washing. The recovered overburden sand would
then be pumped to the mixing station where it would be combined
with thickened waste clay in a 2:1 sand to clay mixture for
final disposal. This waste disposal case would result in sand
tailings fill areas (3,020 acres), 2:1 sand/clay mix areas
(5,492 acres), above-grade clay settling areas capped with 2:1
sand/clay mix (2,847 acres), below-grade clay settling areas
(2,095 acres) and overburden fill areas (1,740 acres). The
average dike height for this case would be 38 feet.
Reclamation
Conventional Plan; Mobil's reclamation plan would reclaim the
15,194 acres disturbed by mining as follows: improved pasture
(11,413 acres) would be developed on above-grade clay settling
areas and sand tailings fill areas with overburden cap; upland
mixed forest (1,271 acres), planted pine (453 acres) and
forested stream channel (277 acres) would be developed in sand
tailings fill areas with overburden cap; freshwater swamp (478
acres) would be developed in above-grade clay settling areas;
and freshwater marsh (1,302 acres) would be developed in
below-grade clay settling areas capped with overburden.
S-7
-------
Sand/Clay Cap Plan; This plan would reclaim the 15,194-acre
disturbed area as follows: improved pasture (11,003 acres)
would be developed in above-grade clay settling areas capped
with 4:1 sand/clay mix and sand tailings areas capped with
overburden; upland mixed forest (1,451 acres), planted pine
(536 acres), and forested stream channel (279 acres) would be
developed in sand tailings capped with overburden; freshwater
swamp (504 acres) would be developed in above-grade clay
settling areas capped with 4:1 sand/clay mix; and freshwater
marsh (1,421 acres) would be developed in below-grade clay
settling areas capped with overburden.
Sand/Clay Mix Plan; This plan would reclaim the 15,194-acre
disturbed area as follows: improved pasture (10,313 acres)
would be developed in above-grade sand/clay mix (2:1) areas,
clay settling areas, and sand tailings capped with overburden;
upland mixed forest (1,826 acres), planted pine (431 acres),
and forested stream channel (263 acres) would be developed in
sand tailings capped with overburden; freshwater swamp (746
acres) would be developed in clay settling areas and in
above-grade and below-grade sand/clay mix (2:1) areas; and
freshwater marsh (1,615 acres) would be developed in below-
grade clay settling areas partially capped with overburden.
Overburden/Clay Mix Plan; This plan would reclaim the 15,194-
acre disturbed area as follows: improved pasture (10,313
acres) would be developed in sand/clay mix areas and sand
tailings capped with overburden; upland mixed forest (1,826
acres), planted pine (431 acres), and forested stream channel
(263 acres) would be developed in sand tailings capped with
overburden; freshwater swamp (746 acres) would be developed in
above-grade and below-grade sand/clay mix areas; and freshwater
marsh (1,615 acres) would be developed in below-grade clay
settling areas partially capped with overburden.
Water Sources
Groundwater; Mobil proposes to utilize three deep wells
(approximately 1,000 feet deep) for the primary source of clean
water for the flotation process and as makeup water for the
recirculation system. The Southwest Florida Water Management
District has granted a Consumptive Use Permit (CUP) for the
withdrawal of 16.413 mgd of groundwater (15.7 mgd from the
Lower Floridan and 0.713 mgd from the Upper Floridan Aquifer).
Surface Water; The 7-day, 10-year low flow in Bowlegs Creek is
zero mgd while that in the Peace River is 7.1 mgd. Since
neither is sufficient to meet the daily water requirements
(16.423 mgd) of the mine, this alternative would require that
an impoundment be constructed on Bowlegs Creek. This source of
water would probably require treatment to upgrade the quality
and could require augmentation by groundwater withdrawal.
S-8
-------
Plant Siting
Gilshey Branch Site; Mobil proposes to locate the
benef iciation plant on the west side of Manley Road
approximately two miles north of County Line Road. Mobil's
main objective in siting the plant was to minimize the energy
required for matrix transfer by locating at the centroid of
matrix pumping.
Other On-Site Locations; The proposed mine site was examined
Torother potentiallocations for the beneficiation plant.
Objectives followed in attempting to locate other sites were to
maximize energy efficiency and minimize disturbance of
environmentally sensitive areas.
Water Discharge
Peace River; Under Mobil's proposed action the clear water
discharge would gravity flow into the Peace River by way of a
vegetated drainage swale (outfall ditch) located along the
railroad route and draining to the Peace River. The mining
operation would have an intermittent discharge from the clear
water pool primarily between the months of May and October.
The discharged volume would be directly dependent on local
rainfall trends and is expected to be the greatest between June
and September, a period when tropical storms are frequent in
Florida. During the wet season the normal and maximum
discharge volumes would be 9 mgd and 20 mgd, respectively.
Bowlegs Creek; Construction of a pump station and a transfer
line from the clear water pool to Bowlegs Creek would be
necessary in order to implement the alternative of discharging
into Bowlegs Creek.
Product Transport
Railroad: Mobil proposes to transfer the wet phosphate rock
produced at South Fort Meade by rail cars to an existing
rock-drying facility at Nichols, Florida. Mobil would
construct a six-mile rail spur from the plant site west to the
existing Seaboard Coast Line track. This would also require
construction of a bridge across the Peace River and a grade
crossing on Mt. Pisgah Road. During full production, 65 rail
cars would be pushed from the benef iciation plant to the main
track and returned twice each day.
Truck: Product transport by diesel truck could be accomplished
during full production with 25-ton capacity trucks making 520
round trips per day from the South Fort Meade Mine to Nichols.
S-9
-------
The No Action Alternative
The no action alternative by EPA would be the denial of an
NPDES permit for the proposed project. The effect of permit
denial would be to precipitate one of three possible actions on
the part of Mobil: (1) termination of the proposed project,
(2) indefinite postponement of the proposed project, or (3) re-
structuring of the project to achieve zero discharge.
Termination of the planned project would allow the existing
environment to remain undisturbed, and the gradual socio-
economic and environmental trends would continue as at present.
The project might be postponed for an indefinite time and then
successfullly pursued by Mobil or another mining company. This
might be expected to occur when high grade phosphate reserves
are depleted and the resource retained on the site becomes
extremely valuable strategically as well as economically.
If EPA denies the NPDES permit, Mobil could still execute a
mining project provided the project could be performed with
zero discharge. Under zero discharge conditions, neither an
NPDES permit nor an Environmental Impact Statement would be
required.
4. EPA's Preferred Alternatives
The alternatives evaluation for the Mobil project is presented
in detail in Section 2.0 of the DEIS. Based on analyses
described in that section, the environmentally preferable
alternative, EPA's preferred alternative, and Mobil's proposed
action (including mitigating measures presented as part °t tm.
proposed action), all coincide with respect to the following
project subsystems:
Mining Method (Dragline)
Matrix Transfer (Pipeline)
Processing (Conventional Beneficiation)
Water Sources (Groundwater Withdrawal)
Plant Siting (Gilshey Branch Site)
Water Discharge (Peace River)
Product Transport (Railroad)
However, they differ with respect to the waste disposal and
recllmaiion project plans. The analysis of .waste disposal and
reclamation alternatives identified the 4:1 sa,nd/cla^aP ^
disposal case and the corresponding reclamation plan as the
environmentally preferable (and therefore EP A',> P
alternatives. A summary of the evaluation of waste
and reclamation alternatives is presented in Table i.
S-10
-------
TABLE 1
SUMMARY OF WASTE DISPOSAL AND RECLAMATION ALTERNATIVE EVALUATION
Conventional
Clay
Item Settling Plan
Average Dike Height of Above-Grade Basins
(feet)
Area of Above-Grade Settling Basins,
clay and/or sand/clay mix (acres)
Area of Above-Grade Clay Settling Basins,
(capped or uncapped)
Area of Above-Grade Clay Settling Basins,
without cap (acres)
Areas of Sand Tailings and Overburden Fill
(acres)
Areas of Below-Grade Settling Basins
(acres)
Land Use Potential Rating (Existing = 10)
a. Structural Stability (Short-Term)
b. Structural Stability (Long-Term)
c. Agronomic Value
Phosphate Resources in Waste Disposal
Areas, with clay (ratio of phosphate to
waste material )
Average Soil Radium-226 Levels of
Reclaimed Landform (pCi/g)
Groundwater Consumption
(mgd)
Dike Failure Risk Rating
(4 = Highest Potential )
Reclaimed Wetland Areas and Reforested
Stream Channels (acres)
Reclaimed Upland Mixed Forested Areas
(acres)
Energy Consumption for Pumping
(105 kWn)
Technology Risks (number of processes
or operations not proven)
Possibility of Contamination by Seepage
from basins to groundwater
(4 = Greatest Probability)
Reduction in Aquifer Recharge
(3 = Greatest Reduction)
39
8,170
8,170
6,681
5,511
1,513
5.1
5.6
5.8
0.44
13.2
16.4
4
2,057
1,271
1,004
0
1
3
Sand/Clay
Cap
Plan
37
8,170
8,170
0
5,511
1,513
5.3
6.4
7.7
0.35
8.9
16.4
1
2,204
1,451
1,252
1
2
3
Sand/Clay
Mix
Plan
35
8,339
4,827
1,642
4,760
2,095
4.8
5.6
6.7
0.24
10.9
16.2
3
2,624
1,826
1,358
1
3
2
Overburden/
Clay Mix
Plan
38
8,339
2,847
0
4,760
2,095
4.9
5.8
6.9
0.15
8.9
16.4+
2
2,624
1,825
2,444
2
4
1
SOURCE: STUDY DATA
S-ll
-------
The EPA preferred alternatives for waste disposal and
reclamation have the principal advantages of a lower (by two
feet) average dike height, reduced surface radiation levels,
improved agronomic properties of the reclaimed soils,
establishment of a perched water table about five feet below
the surface of the reclaimed sand/clay cap areas (providing a
plant growth zone), reduced potential for dam failure because
of decreased active settling acreage, seven percent more
reclaimed wetlands, and improved land use potential with the
4:1 sand/clay mix cap over the clay settling areas due to
increased structural stability. Mobil's proposed action for
waste disposal and reclamation has the principal advantages of
significantly lower energy consumption and the use of proven
technology.
5. Mitigation Measures Recommended by EPA
In addition to identifying the environmentally preferable
alternatives for the project subsystems, EPA's assessment has
focused on developing mitigating measures, not already a part
of the proposed action, which could minimize adverse impacts of
the project. These are discussed in detail in Section 2.11 of
the DEIS. EPA has determined that the following mitigation
measures should be incorporated into the proposed phosphate
mining project.
The practice of high-profile overburden
stacKing to the maximum extent compatible
with toe spoiling of the leach zone.
A program to reduce impacts on the indigo
snake by capturing and relocating indigo
snakes on the site to other suitable habitats
in the region.
A program to evaluate and reduce any poten-
tial impacts to the bald eagle nesting
approximately 3/8 mile outside the mine site.
A monitoring program to assess the wetlands
restoration and re-creation effort to be
undertaken at the mine site.
A program to monitor the Shallow Aquifer to
assess the effectiveness of the perimeter
ditches in preventing dewatering of preserved
areas.
S-12
-------
6. Summary of the Environmental Impacts of the Alternatives
In order to make its determination regarding the NPDES permit
application for the Mobil project, EPA has developed a
comparison between (1) Mobil's Proposed Action, (2) EPA's
preferred alternatives and recommended mitigating measures, and
(3) the no action alternative of permit denial by EPA, which
could lead to termination of the project, postponement of the
project or restructuring of the project to achieve zero
discharge. This comparative analysis is presented in Table 2
(page S-14).
7. EPA's Proposed Action
After careful consideration of these alternatives, EPA proposes
to issue an NPDES permit to Mobil for their proposed South Fort
Meade Phosphate Mine. The project authorized by the permit is
to be the sum of EPA's preferred subsystem alternatives (which
is Mobil's proposed action except in the case of waste disposal
and reclamation). Further, EPA proposes to impose as permit
conditions all the mitigating measures identified as part of
Mobil's proposed action (Section 2.1 of the DEIS and Chapter 2
of the SID) as well as all the mitigating measures recommended
by EPA (Section 2.11 of the DEIS).
S-13
-------
TABLE 2
COMPARISON OF THE ENVIRONMENTAL IMPACTS OF THE ALTERNATIVES
Air Quality,
Meteorology,
and Noise
Geology and
Soils
Radiation
Groundwater
Mobil's Proposed Action
Minor increases in fu-
gitive dust emissions
and emissions from
internal combustion
engines; minor emis-
sions of volatile
reagents ; increased
noise levels in the
vicinity of operating
equipment.
Disruption of the
surface soils and over-
burden strata; removal
of 77 mi 11 ion tons
of phosphate rock;
increased loading
to the Hawthorn pf
17 psi; altering of site
topography; creation
of approximately 7000
A of structurally
and agronomically in-
ferior land.
Disruption of the na-
tural distribution of
radioactive material
within the overburden
and matrix; increased
ganma radiation
levels from reclaimed
surfaces and increased
soil radioactivity.
Lowering of the
piezometric Surface
of the Lower Floridan
Aquifer; lowering of the
Surficial Aquifer near
active mine pits; 47
percent reduction in
natural recharge.
EPA's Preferred Alternatives
Including Mitigation Measures
Same as Mobil's proposed
action.
The No Action Alternatives
Same as Mobil's proposed
action except: increased
loading to Hawthorn Forma-
tion of 16 psi; alteration
to topography not as great
(2 ft. less); possible fur-
ther decrease in level of
CS-10; slightly increase
future effort to recover
phosphate from waste clay;
improved structural and
agronomic characteristics
over the approximately
7000 A of land.
Same as Mobil's pro-
posed action, except that
reclaimed surfaces
would have lower overall
soil radioactivity
and gamma radiation levels.
Same as Mobil's proposed
action, except that a
perched water table would
be established about 5 feet
below the surface in the
reclaimed sand/clay cap
areas.
Termination
No change in
meteorology &
noise levels;
possible air
quality changes
from other
sources.
No change in
geology; no
change in site
soils; preser-
vation of 77
million tons
of phosphate
rock reserves.
No change in
radiation char-
acteristics
of the site.
No change in
existing
groundwater
quantity or
quality.
Postponement
Same as Mobil 's
proposed action.
Possible in-
creased phos-
phate recovery
and more effec-
tive waste dis-
posal , reclama-
tion, and wet-
lands restoration.
Same as Mobil 's
proposed action.
Possible reduction
in groundwater
withdrawals be-
cause of more
effective dewatering
of waste materials
resulting from future
process development.
Achieve Zero Discharge
Same as Mobil's pro-
posed action.
Increased dike heights
and water storage capa-
city; infringement on
Bowlegs Creek preserved
area; less desirable
reclamation plan.
Probable increase in
area covered with waste
clays - the reclaimed
material having the
highest radioactivity
levels.
Possible reduction in
groundwater withdrawals
because of increased
water storage.
Surface Water
Biology
Human Resources
Disruption of surface
water flows from the
mine site; minor alter-
ation in flows fol-
lowing reclamation;
degradation of water
charges from the
mine water system.
Destruction of aqua-
tic and terrestrial
habitats on the mine
site; aquatic habitat
modification due to
reduced surface
water flows and addi-
tion of contaminants;
loss of some
endangered species
individuals; creation
of modified habitats
following reclamation.
Retention of existing
jobs and develop-
ment of new jobs with
comparatively high in-
come; ad valorem and
sales tax revenue for
Polk County, severence
tax revenue for the state
Land Reclamation Trust
Fund, and Florida Insti-
tute of Phosphate Re-
search; maintain employ-
ment for Mobil's Fort
Meade personnel.
Same as Mobil's proposed
action, except that dam
failure potential is
reduced because of de-
creased active settling
areas and 2-foot lower dike
heights.
Same as Mobil's proposed
action, except 8 percent
more wetlands would be
reclaimed, improved soils
for restoration of
vegetation and habitats,
and greater protection of
listed species.
Same as Mobil's proposed
action, except land use
potential improved by 4:1
sand/clay cap surface soil
over clay settling areas.
No change in
surface water
quantity; sur-
face water
quality would
be dependent upon
future land uses in
the area.
No change in
existing aquatic
or terrestrial
ecology.
Loss of jobs
which would be
generated by
the project;
loss of tax
revenue for
Polk County
and the state;
and a loss of
Mobil's invest-
ment.
Same as Mobil's
proposed action.
Possibly more
effective
reclamation.
Potential in-
creased pro-
ject costs; loss
of jobs.
Eliminaton of surface
water quality impacts
resulting from discharge
from mine water system;
increased probability
of dike failure impacts.
Elimination of habitat
modification resulting
from mine water
discharge; increased
probability of dike
failure impacts;
probable increase in
reclaimed land areas
(waste clays) of limited
use (pasture).
Same as Mobil's proposed
action.
S-14
-------
DRAFT EIS TABLE OF CONTENTS
1.0 PURPOSE AND NEED FOR ACTION 1-1
2.0 ALTERNATIVES INCLUDING THE PROPOSED ACTION 2-1
"271 General Description of Mobfl's Proposed Action 2-1
2.2 Mining Method Alternatives 2-18
2.2.1 Dragline Mining (Mobil's Proposed Action) 2-18
2.2.1.1 General Description 2-18
2.2.1.2 Environmental Considerations 2-19
2.2.2 Bucket Wheel Excavation 2-20
2.2.2.1 General Description 2-20
2.2.2.2 Environmental Considerations 2-20
2.2.2.3 Technical Considerations 2-21
2.2.3 Dredge Mining 2-21
2.2.3.1 General Description 2-21
2.2.3.2 Environmental Considerations 2-22
2.2.4 Summary Comparison 2-23
2.3 Matrix Transfer Alternatives 2-23
2.3.1 Pipeline Transfer (Mobil's Proposed Action) 2-23
2.3.1.1 General Description 2-23
2.3.1.2 Environmental Considerations 2-24
2.3.2 Conveyor System 2-24
2.3.2.1 General Description 2-24
2.3.2.2 Environmental Considerations 2-24
2.3.2.3 Technical Considerations 2-25
2.3.3 Truck Transfer 2-26
2.3.3.1 General Description 2-26
2.3.3.2 Environmental Considerations 2-26
2.3.4 Summary Comparison 2-26
2.4 Matrix Processing Alternatives 2-26
2.4.1 Conventional Beneficiation (Mobil's Proposed 2-27
Action)
2.4.1.1 General Description 2-27
2.4,1.2 Environmental Considerations 2-33
2.4.2 Dry Separation 2-33
2.4.2.1 General Description 2-33
2.4.2.2 Environmental Considerations 2-34
2.4.4 Summary Comparison 2-34
2.5 Waste Disposal Alternatives 2-35
2.5.1 Conventional Clay Settling Case (Mobil's 2-35
Proposed Action)
-------
2.5.1.1 General Description 2-35
2.5.1.2 Environmental Considerations 2-41
2.5.2 Sand/Clay Cap Case 2-44
2.5.2.1 General Description 2-44
2.5.2.2 Environmental Considerations 2-50
2.5.3 Sand/Clay Mix Case 2-50
2.5.3.1 General Description 2-50
2.5.3.2 Environmental Considerations 2-57
2.5.4 Overburden/Clay Mix Case 2-58
2.5.4.1 General Description 2-58
2.5.4.2 Environmental Considerations 2-62
2.5.5 Summary Comparison 2-63
2.6 Reclamation Alternatives 2-65
2.6.1 Conventional Clay Settling Plan (Mobil's 2-6b
Proposed Action)
2.6.1.1 General Description 2-65
2.6.1.2 Environmental Considerations 2-80
2.6.2 Sand/Clay Cap Plan 2-80
2.6.2.1 General Description 2-80
2.6.2.2 Environmental Considerations 2-92
2.6.3 Sand/Clay Mix Plan 2-92
2.6.3.1 General Description 2-92
2.6.3.2 Environmental Considerations 2-102
2.6.4 Overburden/Clay Mix Plan 2-103
2.6.4.1 General Description 2-103
2.6.4.2 Environmental Considerations 2-105
2.6.5 Summary Comparison 2-105
2.7 Water Source Alternatives 2-106
2.7.1 Groundwater Withdrawal (Mobil's Proposed 2-111
Action)
2.7.1.1 General Description 2-111
2.7.1.2 Environmental Considerations 2-111
2.7.2 Surface Water Impoundment 2-112
2.7.2.1 General Description 2-112
2.7.2.2 Environmental Considerations 2-112
2.7.3 Summary Comparison 2-112
2.8 Plant Siting Alternatives 2-113
2.8.1 Gilshey Branch (Mobil's Proposed Action) Z-iiJ
2.8.1.1 General Description 2-113
2.8.1.2 Environmental Considerations 2-113
-------
2.8.2 Other On-Site Locations 2-114
2.8.2.1 General Description 2-114
2.8.2.2 Environmental Considerations 2-114
2.8.3 Summary Comparison 2-114
2.9 Water Discharge Alternatives 2-114
2.9.1 The Peace River (Mobil's Proposed Action) 2-115
2.9.1.1 General Description 2-115
2.9.1.2 Environmental Considerations 2-115
2.9.2 Bowlegs Creek 2-115
2.9.2.1 General Description 2-115
2.9.2.2 Environmental Considerations 2-116
2.9.3 Summary Comparison 2-116
2.10 Product Transport Alternatives 2-116
2.10.1 Railroad (Mobil's Proposed Action) 2-117
2.10.1.1 General Description 2-117
2.10.1.2 Environmental Considerations 2-117
2.10.2 Truck Product Transport 2-117
2.10.2.1 General Description 2-117
2.10.2.2 Environmental Considerations 2-118
2.10.3 Summary Comparison 2-118
2.11 Mitigation Measures 2-118
2.11.1 Geology and Soils 2-118
2.11.2 Biological Resources 2-118
2.11.3 Groundwater 2-120
2.12 The No Action Alternative 2-120
2.12.1 Termination of The Project 2-120
2.12.2 Postponement of The Project 2-123
2.12.3 Achieving a Zero Discharge 2-123
2.13 EPA's Preferred Alternatives, Mitigating Measures 2-124
and Recommended Action
3.0 THE AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES 3-1
3.1 Meteorology, Air Quality and Noise 3-2
3.1.1 The Affected Environment 3-2
3.1.1.1 Meteorology and Climatology 3-2
3.1.1.2 Air Quality 3-5
3.1.1.3 Noise 3-9
3.1.2 Environmental Consequences of the Alternatives 3-11
3.1.2.1 The No Action Alternative 3-11
iii
-------
3.1.2.2 The Action Alternatives Including 3-11
the Proposed Action
3.2 Geology And Soils ^-18
3.2.1 The Affected Environment J-J°
3.2.1.1 Geology ^-J°
3.2.1.2 Soils J-^°
3.2.2 Environmental Consequences of the Alternatives 3-28
3.2.2.1 The No Action Alternative 3-*!b
3.2.2.2 The Action Alternatives Including -i-28
the Proposed Action
j -1Q
3.3 Radiation r~~
3.3.1 The Affected Environment *-#*
3.3.1.1 Uranium, Radioactivity and Exposure 3-40
3.3.1.2 Uranium and Phosphate Deposits 3-41
3.3.1.3 Radiation Existing at the Site 3-42
3.3.2 Environmental Consequences of the Alternatives 3-48
3.3.2.1 The No Action Alternative 3-48
3.3.2.2 The Action Alternatives Including 3-49
the Proposed Action
3.4 Groundwater -*-67
3.4.1 The Affected Environment ^'
3.4.1.1 Groundwater System *-*>/
3.4.1.2 Groundwater Quantity J-^
3.4.1.3 Groundwater Quality 3-72
3.4.2 Environmental Consequences of the Alternatives 3-74
3.4.2.1 The No Action Alternative 3-74
3.4.2.2 The Action Alternatives Including 3-74
the Proposed Action
3.5 Surface Water |-86
3.5.1 The Affected Environment -T°°
3.5.1.1 Regional Description J-ťo
3.5.1.2 Site Description J-ťť
3.5.1.3 Surface Water Characteristics 3-88
3.5.1.4 Surface Water Utilization 3-95
352 Environmental Consequences of the Alternatives 3-98
3.5.2.1 The No Action Alternative 3-98
3.5.2.2 The Action Alternatives Including 3-98
the Proposed Action
3-117
3.6 Biology
3.6.1 The Affected Environment
3.6.1.1 Regional Setting
3.6.1.2 Site Description
3.6.2 Environmental Consequences of the Alternatives 3-135
3.6.2.1 The Mo Action Alternative 3-l.ib
IV
-------
3.6.2.2 The Action Alternatives Including 3-136
the Proposed Action
3.7 Human Resources 3-155
3.7.1 The Affected Environment 3-155
3.7.1.1 Demographics and Economics 3-155
3.7.1.2 Cultural Resources 3-156
3.7.1.3 Community Services 3-156
3.7.1.4 Land Use 3-157
3.7.1.5 Transportation 3-158
3.7.2 Environmental Consequences of the Alternatives 3-160
3.7.2.1 The No Action Alternative 3-160
Z.I.2.2 The Action Alternatives Including 3-161
the Proposed Action
3.8 References 3-167
4.0 SHORT-TERM USE VERSUS LONG-TERM PRODUCTIVITY 4-1
4.1 Meteorology, Air Quality and Noise 4-1
4.1.1 Short-Term 4-1
4.1.2 Long-Term 4-1
4.2 Geology and Soils 4-2
4.2.1 Short-Term 4-2
4.2.2 Long-Term 4-2
4.3 Radiation 4-2
4.3.1 Short-Term 4-2
4.3.2 Long-Term 4-2
4.4 Groundwater 4-2
4.4.1 Short-Term 4-2
4.4.2 Long-Term 4-3
4.5 Surface Water 4-3
4.5.1 Short-Term 4-3
4.5.2 Long-Term 4-3
4.6 Biology 4-4
4.6.1 Short-Term 4-4
4.6.2 Long-Term 4-4
4.7 Human Resources 4-5
4.7.1 Short-Term 4-5
4.7.2 Long-Term 4-5
5.0 IRREVERSIBLE OR IRRETRIEVABLE COMMITMENTS OF RESOURCES 5-1
5.1 Depletion of Mineral Resources 5-1
5.2 Landform Changes 5-3
5.3 Chemicals and Reagents 5-3
5.4 Water 5-4
5.5 Energy 5-4
-------
5.6 Fish and Wildlife Habitat 5-4
5.7 Historical and Archaeological Resources 5-6
5.8 References 5-6
6.0 COMPARISON OF PROPOSED ACTIVITY WITH AREAWIDE EIS 6-1
KfcCUMMENDATIONS
6.1 Mining and Beneficiation Requirements 6-1
6.1.1 Eliminate Rock-Drying 6-1
6.1.2 Meet Effluent Limitations 6-1
6.1.3 Eliminate Above-Ground Disposal Areas 6-2
6.1.4 Meet Consumptive Use Permit Requirements 6-3
6.1.5 Provide for Recirculation of Water 6-4
6.1.6 Use Connector Wells 6-4
6.1.7 Address Proposed Radiation Requirements 6-4
6.1.8 Meet Reclamation Requirements 6-6
6.1.9 Protection and Restoration of Habitat 6-6
6.1.10 Protect or Restore Wetlands 6-9
6.1.11 Preservation of Archaeological or Historical 6-11
Sites
6.2 References 6-11
7.0 COORDINATION 7-1
7.1 DEIS Coordination List 7-1
7.2 Public Participation and Scoping 7-2
7.3 Consultation With U.S. Department of Interior 7-3
7.4 Consultation With State Historic Preservation Officer 7-4
7.5 Coordination With U.S. Army Corps of Engineers 7-5
7.6 Coordination with U.S. Department of Interior 7-5
7.7 References 7-6
8.0 LIST OF PREPARERS 8-1
INDEX 1-1
APPENDIX
Draft NPDES Permit
A-l
-------
LIST OF FIGURES
Figure Page
1.0-A Location of Proposed South Fort Meade Mine Site 1-2
1.0-B Specific Site Location of Proposed Mine 1-3
2.1-A Mining Sequence: Dragline I 2-3
2.1-B Mining Sequence: Dragline II 2-4
2.1-C Undisturbed Areas 2-5
2.1-D Conceptual Diagram of Mining and Waste Disposal 2-8
2.1-E Post Reclamation Land Use (Conventional Plan) 2-11
2.1-F Proposed Plant Site Location and Railroad Route 2-14
2.4-A Generalized Process Flow Sheet 2-28
2.4-B Washer Process 2-29
2.4-C Feed Preparation Process 2-30
2.4-D Flotation Process 2-32
2.5-A Waste Clay Settling Method 2-38
2.5-B Conventional Waste Disposal 2-39
2.5-C Waste Disposal Areas - Sand/Clay Cap Case 2-45
2.5-D Waste Disposal Areas - Sand/Clay Mix Case 2-52
2.5-E Conceptual Waste Disposal Areas - Overburden Mix Case 2-59
2.5-F Overburden/Clay Mixing Concept 2-61
2.6-A Reclaimed Stream Channels - Conventional Plan 2-69
2.6-B Formation of Shallow Depressions 2-71
2.6-C Reforestation of Stream Channels 2-73
2.6-D Revegetation of Below-Grade Clay Reclamation Area 2-75
2.6-E Post Reclamation Land Use - Sand/Clay Cap Plan 2-83
2.6-F Reclaimed Stream Channels - Sand/Clay Cap Plan 2-86
2.6-G Post Reclamation Land Use - Sand/Clay Mix Plan 2-95
2.6-H Reclaimed Stream Channels - Sand/Clay Mix Plan 2-98
2.7-A Mine Water System 2-110
3.2-A Stratigraphic Section of Proposed Mine Site 3-19
3.2-B Soil Series Map 3-23
3.2-C Soil Association Map 3-26
3.3-A Schematic Diagram of Beneficiation 3-51
3.4-A Hydrogeologic Cross Section of the Proposed Mine Site 3-68
3.4-B Graph of Water Level Fluctuations 3-70
3.4-C Lower Floridan Aquifer Drawdown Projection 3-78
3.5-A The Peace River and Tributaries 3-87
J.5-B Drainage Basins 3-89
3.5-C Total Disturbed Acreage 3-100
3.6-A Land Use and Cover 3-118
3.6-B Wetland Delineation Map 3-133
3.7-A Transportation Facilities 3-159
7.3-A Location of Eagle's Nest 7-5
7.6-A BLM Mineral Reserves 7-8
-------
LIST OF TABLES
Table
2.1-1 Land Use Categories (Conventional Plan) 2-10
2.1-2 Flow Requirements for Each Water Use 2-12
2.1-3 Mine Water Balance 2-13
2.5-1 Summary of Matrix Sand/Clay Ratios 2-36
2.5-2 Acreages, Dike Heights, Fill Levels and Reclaimed 2-40
Settling Areas (Conventional Case)
2.5-3 Active Settling Acreage - Conventional Case 2-42
2.5-4 Sand Tailings Fill Acreage - Conventional Case 2-43
2.5-5 Clay Settling Areas - Sand/Clay Cap Case 2-46
2.5-6 Active Settling Acreage - Sand/Clay Cap Case 2-48
2.5-7 Sand Tailings Fill Areas - Sand/Clay Cap Case 2-49
2.5-8 Clay Settling Areas - Sand/Clay Mix Case 2-53
2.5-9 Sand Tailings Fill Areas - Sand/Clay Mix Case 2-55
2.5-10 Dike Heights and Elevations - Sand/Clay Mix Case 2-56
2.5-11 Summary of Waste Disposal Evaluation 2-64
2.6-1 Annual Reclamation Schedule - Conventional Plan 2-79
2.6-2 Land Use Categories - Sand/Clay Cap Plan 2-82
2.6-3 Annual Reclamation Schedule - Sand/Clay Cap Plan 2-91
2.6-4 Land Use Categories - Sand/Clay Mix Plan 2-93
2.6-5 Annual Reclamation Schedule - Sand/Clay Mix Plan 2-101
2.6-6 Land Use Categories - Overburden/Clay Mix Plan 2-104
2.6-7 Land Use Potential - Short-Term 2-107
2.6-8 Land Use Potential - Long-Term 2-108
2.6-9 Land Use Potential - Agronomic Rating 2-109
2.13-1 Comparison of the Environmental Impacts of the 2-126
Alternatives
3.1-1 Climatological Summary for Lakeland, Florida 3-3
3.1-2 Air Quality Standards for TSP and S0? and Vegetative 3-6
Fluorides Standards
3.1-3 Noise Survey Results 3-10
3.2-1 Analyses of Overburden, Sand Tailings and Phosphatic 3-21
Clay Samples
3.2-2 Soil Distribution 3_24
3.2-3 Soil Ratings by Soil Association 3-27
3.2-4 Description of Potential of Reclaimed Landforms 3-32
3.3-1 Summary of Radiological Characteristics 3-43
3.3-2 Radium-226 Content of Matrix and Fractions 3-46
3.3-3 Estimated Radiological Characteristics for Reclaimed 3-54
Lands (Conventional Plan)
3.3-4 Estimated Radiological Characteristics for Reclaimed 3-59
Lands (Sand/Clay Cap Plan)
v i i i
-------
Table
3.3-5 Estimated Radiological Characteristics for Reclaimed
Lands (Sand/Clay Mix Plan)
3.3-6 Estimated Radiological Characteristics for Reclaimed
Lands (Overburden Mix Plan)
3.4-1 Chemical Analysis of Groundwater
3.4-2 Comparison of Shallow Aquifer Water to Clay Settling
Area Supernatant
3.5-1 Average Monthly Flows for the Peace River and Bowlegs 3-91
Creek
3.5-2 Water Quality Data Summaries for the Peace River 3-92
3.5-3 State of Florida and Federal Water Quality Criteria 3-93
3.5-4 Water Quality Data Summaries for Bowlegs Creek 3-94
3.5-5 Average Monthly Flows Calculated for On-Site 3-96
Tributaries
3.5-6 Mean Water Quality of On-Site Tributaries 3-97
3.5-7 Comparison of Existing and Post Reclamation 3-106
Drainage Areas (Conventional Plan)
3.5-8 Comparison of Existing and Post Reclamation 3-109
Drainage Areas (Sand/Clay Cap Plan)
3.5-9 Comparison of Existing and Post Reclamation 3-110
Drainage Areas (Sand/Clay Mix Plan)
3.5-10 Impact of Clear Water Pool Discharge on the Peace 3-113
River
3.5-11 Comparison of Surface Water Quality Near the Site 3-115
to Clay Settling Area Discharges
3.6-1 Existing Acreage by Land Use and Cover Type 3-119
3.6-2 Disturbed and Undisturbed Acreage by Land Use 3-137
and Cover Type
3.6-3 Waste Disposal Acreage 3-146
3.6-4 Acreages by Land Use and Cover Classifications for 3-150
Reclamation Cases
3.7-1 Land Use Classifications of Reclaimed Land 3-163
6.1-1 Effect of Mobil's Proposed Reclamation Plan 6-8
6.1-2 Effect of EPA's Preferred Alternative Reclamation Plan 6-9
8.0-1 Persons Primarily Responsible for Preparing the DEIS 8-2
8.0-2 Organizations Responsible for Gathering the Basic Data 8-3
-------
1.0 PURPOSE AND NEED FOR ACTION
Mobil Chemical Company mines, processes and ships phosphate ore in the central
Florida area. Mobil currently operates the Fort Meade mine located in Polk
County, Florida. Mobil is proposing the development of new phosphate mining,
beneficiation and transshipment facilities in southern Polk County, Florida.
The new facility, the South Fort Meade Mine, would replace Mobil's Fort Meade
Mine when the phosphate reserves there are depleted. The South Fort Meade
Mine would be located on approximately 16,300 acres lying ten miles southeast
of the Fort Meade Mine (Figure 1.0-A, 1.0-B).
This new facility would allow Mobil to maintain a continuous supply of phos-
phate ore to its customers. The annual production of the proposed facility,
at full capacity, would be 3.4 million tons of phosphate rock. The develop-
ment would result in the disturbance of approximately 15,200 acres of the
16,300-acre tract. The proposed mining operation would produce 77 million
tons of wet phosphate rock over the 25-year life of the mine.
As required by the Federal Water Pollution Control Act, which was amended by
the Clean Water Act of 1977, Mobil has applied to the U.S. Environmental Protec-
tion Agency (EPA) for a National Pollution Discharge Elimination System
(NPDES) permit for the proposed South Fort Meade Mine. The EPA Regional
Administrator has determined that the discharge constitutes a "new source"
requiring issuance of an NPDES permit. The granting of an NPDES Permit is a
major Federal action significantly affecting the quality of the human environ-
ment. Therefore, EPA is required by the National Environmental Policy Act of
1969 (NEPA) to prepare an Environmental Impact Statement (EIS) for Mobil's
South Fort Meade Mine. This draft EIS has been prepared by a third party
contractor under the direction and review of EPA, Region IV.
1-1
-------
FIGURE 1.0-A
LOCATION OF PROPOSED
SOUTH FORT MEADE MINE SITE
POLK COUNTY
I HANCOCK
SOUTH FORT MEADE
MINE SITE
WEECHOSEE CO
DESOTO CO
SOURCE: MOBIL
1-2
-------
2.0 ALTERNATIVES INCLUDING THE PROPOSED ACTION
2.1 GENERAL DESCRIPTION OF MOBIL'S PROPOSED ACTION
Mobil has designed an integrated plan for mining and processing phosphate rock
at the proposed South Fort Meade Mine. Mobil's proposed action is comprised
of individual mining subsystems that, when combined, provide a total system
capable of meeting Mobil's production objectives. The mining subsystems nec-
essary for the South Fort Meade operation are shown below.
Mining Subsystem
Mining Method
Matrix Transfer
Processing
Waste Disposal
Reclamation
Water Sources
Plant Siting
Water Discharge
Product Transport
Mobil's South Fort Meade mining operation has been designed to produce approx-
imately 3.4 million tons of phosphate rock annually. The mine would be devel-
oped in two phases with Phase I scheduled to start up in 1984 following a 21-
month construction period. Phase I operations, with an estimated capacity of
1.7 million tons per year, would include one dragline and an associated benefi-
ciation plant. The start up of Phase II is planned for 1987 following a simi-
lar 21-month construction interval. Facilities comparable to Phase I would be
developed in Phase II, increasing production capacity to 3.4 million tons per
year.
Equipment and procedures similar to those presently used in Mobil's two Flori-
da phosphate mines as well as in other central Florida phosphate mines are
2-1
-------
proposed for the new facility. When in full production, two electrically pow-
ered walking draglines (45-cubic yard capacity each) would operate simultan-
eously, mining and extracting phosphate from separate areas. Mining operations
would be scheduled on an around-the-clock basis, seven days a week, dependent
upon production levels and sales requirements. The mining sequence, illus-
trated in Figures 2.1-A and 8, is proposed to continue for 25 years with re-
clamation activities extending 10 years beyond the life of the mine. Each
dragline would follow a sequence which balances production and grade require-
ments and facilitates water recirculation, waste disposal and reclamation
activities. If production and sales requirements change, the length of the
mine operation may also be changed.
The proposed mine operation would disturb approximately 15,194 acres or 93
percent of the site. Approximately 13,340 acres or 88 percent of the dis-
turbed acreage is scheduled for actual mining. Another 1,854 unmined acres
would be disturbed by various activities associated with mining and process-
ing. Of that total, 1,320 acres would be required for initial waste disposal,
124 acres would be occupied by ore processing and support facilities, and 410
acres of unmined setbacks from property boundaries and public rights-of-way
would be disturbed by adjacent mining and waste disposal activities. Existing
land use patterns would continue on reserve lands until those lands are sched-
uled for mining. Approximately 1,094 acres would remain undisturbed.
Figure 2.1-C identifies the three areas preserved from mining. The preserved
areas include the area below the 25-year flood elevation along the Peace
River, a corridor along Bowlegs Creek approximately 660 feet in width, and a
unit centrally located on the eastern boundary of the property. These areas
occupy about 1,094 acres, or approximately 6.7 percent of the total surface
area.
To gain access to mining parcels north of Bowlegs Creek, a dragline crossing
would be located at an existing ford. Bowlegs Creek is scheduled to be
crossed in 1999 and at the same location again in 2002. Woody vegetation in
the corridor to the crossing would be cleared to about twice the width of the
dragline and a culvert would be placed in the creek with earth backfilled
around it. After each crossing, grass cover would be established to prevent
2-2
-------
MINING SEQUENCE: DRAGLINE I
1998ADRAGLINE
CROSSING
1MILE
CD
OUTPARCELS (PRIVATELY OWNED)
SOURCE: MOBIL
-------
MINING SEQUENCE: DRAGLINE II
COUNTY LINt HUAU
at
OUTPARCELS (PRIVATELY OWNED)
SOURCE: MOBIL
-------
UNDISTURBED AREAS
>
en
T33S
SOURCE: ZELLARS-WILLIAMS
Scale
0 ~l/2 /mi/e
LEGEND
UNDISTURBED AREAS
WETLANDS TO REMAIN
UNDISTURBED
-------
erosion and runoff in the cleared corridor. After the second crossing in
2002, the culvert would be removed and the stream would be re-established.
Tree species characteristic of wetlands would be planted to supplement the
grass cover in the corridor.
After the matrix is mined, it would be slurried with water (18,750 gallons per
minute [gpm]) and pumped via pipeline to the beneficiation plant. The matrix
slurry would average about 35 percent solids. Each mining operation would
have a separate pumping system to deliver the slurry to the plant. The pipe-
line routes would change as the mining areas move during the life of the mine,
and the matrix pipeline would be routed across Bowlegs Creek from years 1999
through 2003. Double-walled pipe would be used at the matrix pipeline stream
crossing to contain the slurry in the event of a leak.
At the beneficiation plant, the phosphate rock would be separated from the
matrix slurry. The process operations include washing, feed preparation and
flotation. The matrix slurry received at the beneficiation plant would con-
tain phosphate, clay and sand. The washer would separate the matrix by par-
ticle size into two components: large phosphate pebble and a mixture of
smaller sand, phosphate and clay. The pebble would then be routed to wet rock
storage piles, and the undersized material would be routed to feed prepara-
tion. In the feed preparation process, clay would be removed from the under-
sized material by hydro-cyclones. The waste clay would be pumped from the feed
preparation area to the waste disposal area. The remaining undersized materi-
al or flotation feed would be further separated according to particle size by
a hydro-sizer into fine, coarse and sizer rock material. The three materials
would then be routed to the flotation process where reagents would be added to
separate the sand from the concentrate products. The reagents used in this pro-
cess include No. 5 fuel oil, caustic, fatty acid, amine, kerosene, and
sulfuric acid. The sand tailings from the flotation process would be pumped
to the waste disposal area. The concentrate product from the flotation
process would then be dewatered and retained in storage bins until shipment.
The beneficiation plant would produce waste clays and sand tailings. These
residual clay and sand wastes would be redeposited on the South Fort Meade
2-6
-------
property in clay impoundment areas and sand tailings backfill areas (Figure
2.1-D). The estimated waste quantities would be approximately 132 million
tons of clay and 158 million tons of sand tailings. For each ton of phosphate
product produced at the proposed South Fort Meade Mine, 1.71 tons (dry weight)
of clay and 2.05 tons (dry weight) of sand would be produced.
Mobil proposes to use conventional methods for disposal of waste sand tailings
and clay (Figure 2.1-D). Sand tailings would be principally used to backfill
mined areas (5,034 acres), and waste clays would be contained behind earthen
dikes constructed on natural ground (1,320 acres) or constructed in mined
areas (8,363 acres). Average dike heights would be 38.7 feet above grade.
The estimated power consumption for pumping waste sand and clays would be
1,004 x 106 kWh over the life of the mine.
The design and construction of all impoundment dikes at the South Fort Meade
Mine would comply with the provisions of Chapter 17-9 of the Florida Admini-
strative Code. The dikes would be designed by a professional engineer regis-
tered in Florida and would be inspected regularly. The vegetation and soil
cover on the face of each dike would be examined daily. The elevation of the
impounded water, the amount of freeboard remaining, the condition of the drain-
age ditches, spillways and water control structures would also be inspected
daily. Piezometers installed to monitor water levels and seepage patterns
would be checked monthly. A qualified engineer would make an annual inspec-
tion of all retention dikes on the site, including an analysis of the piezo-
metric readings and a review of all inspection reports to evaluate the effec-
tiveness of the maintenance program.
During the course of mining, Mobil would disturb and reclaim approximately
15,194 acres of the South Fort Meade Mine site. Of the 2,055 acres of wet-
lands on the site, 1,923 acres would be disturbed by mining. When reclamation
is complete, the total wetland acreage would be approximately 93 percent of
that existing on the site; the combined forested stream channel and wetland
acreage would exceed the existing wetland acreage by approximately seven per-
cent. The reclaimed site is also scheduled to have approximately 1,940 acres
planted as upland hardwood and mixed forest. Reclaimed upland mixed forest
would serve to expand the forested zone along the Peace River and Bowlegs
2-7
-------
CONCEPTUAL DIAGRAM OF MINING & WASTE DISPOSAL
0
wJS:.li|
&Łwft$w
.'r.'.i :>.-.'
JMftV&iK
SAND TAILINGS
FILL AREA
SLUICING
PIT
DRAGLINE
MINING AREA
RR
M MiM M I I I I M I I I I M I
SAND TAILINGS
><
WET ROCK
STORAGE
MINING AREA
mjDRAQLINE
31
t t I I M
4-H-ť
I I I I I I I I I I I
IIHII
14444414
'"*>''
PLANT SITE
DEEP WELL
RETURN WATER
SOURCE: MOBIL
CLEAR WATER POOL
CLAY
STORAGE
CD
70
'
-------
Creek and provide densely forested stands. The acreage distribution of the
various land use categories is shown for both reclaimed and disturbed land in
Table 2.1-1. Figure 2.1-E shows the reclaimed areas on the site.
The three sources of water for the mining operation would be ore water, rain-
fall and groundwater. Ore water would generally be unavailable for process
purposes since it would be contained in matrix clays. Rainfall varies season-
ally and is approximately equivalent to evaporation; it is, therefore, not a
consistent source of supply. The most reliable water supply would be the deep
aquifer system tapped by wells which would provide high quality process water
on a continuous basis. Mobil proposes to withdraw 15.7 mgd for flotation pro-
cess and makeup water from the Lower Floridan Aquifer utilizing three wells to
a depth of approximately 1,000 feet. Groundwater would also be withdrawn for
pump seal water and potable water from the Upper Floridan Aquifer at a rate of
0.713 mgd using wells approximately 240 feet deep. The withdrawal points for
the Upper Floridan Aquifer water source would change during the life of the
mine. The proposed withdrawal of 16.413 mgd of groundwater was approved by
the Southwest Florida Water Management District (SWFWMD), and Consumptive Use
Permit (CUP) No. 205403 was issued to Mobil on October 7, 1980.
Water management techniques at the South Fort Meade Mine would permit water to
be recovered from ore transportation, washing, feed preparation, flotation
processes and waste disposal, thus minimizing effluent discharges and consump-
tive uses. Estimated flow requirements for each water use are shown in Table
2.1-2, and a summary of the water balance is presented in Table 2.1-3.
The processing plant would be located on the west side of Manley Road, approxi-
mately two miles north of County Line Road (Figure 1.0-B and 2.1-F). The
plant would be located in an area that is now primarily pasture. This loca-
tion is the matrix centroid of pumping distances on the site and would be the
most energy efficient location. The plant site would be adjacent to an exis-
ting road providing easy access for employees and deliveries. During con-
struction and operation of the beneficiation plant, fugitive emissions from
vehicular traffic would be minimized by paving the plant roads.
The primary water discharge from the mining area would occur from the 45-acre
clear water pool adjacent to the processing facility. The clear water
2-9
-------
TABLE 2.1-1
LAND USE CATEGORIES
(Conventional Plan)
Land Use
Category
Improved Pasture
Cutover Flatwoods
Upland Hardwood
Forest
Upland Mixed
Forest
Planted Pine
Water Areas
Forested Stream
Channels
Freshwater Swamp
Freshwater Marsh
TOTAL
Reclaimed
Acreage
11,413
0
0
1,271
453
0
277
478
1,302
15,194
Undisturbed
Acreage
108
182
664
5
0
3
0
111
21
1,094
Post
Mining
Acreage
11,521
182
664
1,276
453
3
277
589
1,323
16,288
SOURCE: MOBIL
2-10
-------
POST RECLAMATION LAND USE
CONVENTIONAL PLAN
Xy| PLANTED PINE
UNDISTURBED AREAS
goV^t^BY MOBIL)
'ssw STREAM
SOURCE: MOBIL
-------
TABLE 2.1-2
FLOW REQUIREMENTS FOR EACH WATER USE
Water Use
Slurry Transport Water
Pump Seal Water
Washing/Dilution Water
Rinsing and Feed
Preparation Water
Flotation Process and
Makeup Water
Miscellaneous Potable Water
TOTAL
New Water
(mgd)
0
0.691^
0
0
15.7^)
0.022^
16.413
Recycled Water
(mgd)
27.0
0
52.0
38.0
40.2
-
157.2
Total Water
Usage
(mgd)
27.0
0.691
52.0
38.0
55.9
0.022
173.613
(1) Upper Floridan Aquifer
(2) Lower Floridan Aquifer
SOURCE: MOBIL
2-12
-------
TABLE 2.1-3
MINE WATER BALANCE
WATER SOURCES WATER DISPOSITION
FUNCTION/SOURCE VOLUME, MGD VOLUME. MGD DISPOSITION
0.691
SEAL WATER
(UPPER FLORIDAN
AQUIFER)
MAKEUP WATER
(LOWER FLORIDAN AQUIFER)
AMINE FLOTATION PROCESS WATER
(LOWER FLORIDAN AQUIFER)
POTABLE WATER (UPPER FLORIDAN
AQUIFER)
TOTAL FROM GROUNDWATER SUPPLY
ORE WATER (NON-SUPPLY)
TOTAL
L_
FEED
PREPARATION
1
3.389
FLOTATION
DISCHARGE TO SURFACE WATER
(ONLY IN HEAVY RAINFALL PERIOD)
r~
L
i
OM^0 ._.
16.413
2.593~
-H
*
SAND DISPOSAL
CLAY DISPOSAL
SUPPORT
FACILITIES
~- Ť Ttr ^. TAII iurr
-M
1
1
1
-H
i
i
i
RECYCLE WATER 1
157.2 MGD
^ I , / *- J *" IM1 L.I MUJ
.713 ** SEEPAGE
Hfid? . . kť UAtir PIAY
16.413 TOTAL DISP
w > KQT ^ WASTE CLAY
(NON-SUPPL
19.006
19.006
TOTAL
SOURCE: MOBIL
-------
PROPOSED PLANT SITE LOCATION
AND RAILROAD ROUTE
ro
i
COUNTY LINE ROAD
1/2 Ml
LEGEND
SOURCE: MOBL
OUTPARCELS
PROPOSED RAILROAD ROUTE
en
i
*
'
-------
discharge would flow into the Peace River by way of a vegetated drainage swale
(outfall ditch) constructed parallel to the railroad route. There would be
additional outfalls associated with the spillways of individual settling
basins, but these would only discharge in extreme circumstances when excessive
rainfall threatens to overtop the basins. These settling basin discharges
could intermittently occur for the period between the construction of the set-
tling basin and the reclamation of the basin. Over the active mining period,
the location of the emergency discharge outfalls would shift as basins are
reclaimed. The discharged water would be directed to Bowlegs Creek and Ste-
phens Branch. Special precautionary measures would be implemented in the
event of hurricane warnings in the area including draining storage basins of
excess water to prevent overtopping the dikes.
Mobil proposes to construct a six-mile railroad spur from the beneficiation
plant to the Seaboard Coast Line track west of the site in order to transport
the phosphate product. A bridge would be built to cross the Peace River and a
grade crossing would be required on Mt. Pisgah Road. The proposed railroad
route is depicted in Figure 2.1-F.
Mobil's proposed action also includes a number of measures designed to reduce
the potential for adverse impacts on the environment. These are described
below by the components with which they are most closely associated.
Mining
o The existing vegetative cover would be maintained on all land for
which mining or support activities are not imminent.
o The vegetative cover on about seven percent of the mine site would be
preserved, including the most important wetland acreages.
o The dragline crossing of Bowlegs Creek would be at an existing ford,
disturbing the least total area, particularly the least wetland area.
o The dragline crossing through the preserved portion of Bowlegs Creek
would be along a single corridor.
o Vegetation would be established on the approach to the creek crossing
and would be maintained until the final crossing is made.
o Fill introduced into creek channels during dragline crossings would be
removed after the crossing and the banks immediately stabilized with
vegetation.
2-15
-------
o Perimeter rim ditches would be used, where necessary, to maintain Sur-
ficial Aquifer levels at adjacent property boundaries and within the
preserved areas.
o Pocket toe spoiling, a technique in which overburden from near the
interface with the matrix is placed in a pocket at the toe of the spoil
pile and covered with overburden from the upper strata would be imple-
mented as a leach zone management practice.
Matrix Transport
o The matrix pipeline crossing of Bowlegs Creek would be in the same cor-
ridor as the dragline crossing, therefore disturbing the least total
area, particularly the least wetland area.
o Double-walled pipe would be used at the matrix pipeline stream crossing
to contain the slurry in the event of a leak.
o The slurry pipeline would be inspected several times each day to identi-
fy any leakage.
Matrix Processing
o Roads in the plant area would be paved before construction to reduce
dust.
o During plant construction and operation, perimeter ditches would be
used to contain runoff from the plant site area.
o Storage facilities for reagents, fuel, lubricants, etc. would be above
ground within a walled or diked area designed to contain spillage.
o Safety and spill control training programs would be implemented for
operations and maintenance personnel.
Water Management System
o Groundwater withdrawal may be reduced in dry periods to comply with
Southwest Florida Water Management District (SWFWMD) regulations.
o Water would be recycled in the mining, processing and waste disposal
operations to the maximum extent possible.
Waste Sand and Clay Disposal
o The design and construction of dikes required for the impoundment of
clay and sand/clay wastes would comply with all provisions of Chapter
17-9 of the Florida Administrative Code.
2-16
-------
o Dike faces would be planted in grasses to inhibit wind and water e-
rosion and would be mowed as necessary for visual inspection.
o All dikes would be inspected daily by a trained Mobil employee and an-
nually by a registered engineer.
Reclamation
o All dikes and ditches would be recontoured as required by the Florida
Department of Natural Resources.
o All disturbed land would be revegetated.
o When reclamation is complete, the total wetland acreage (1,923 acres)
would be approximately 93 percent of that now existing on the site; the
combined forested stream channel and wetland acreage would total 2,200
acres, exceeding the existing wetland acreage by approximately seven
percent.
o Planted pine would be harvested prior to mining and the site would be
reclaimed with 34 percent more area of planted pine cover (453 acres).
o Reclaimed upland mixed forest would expand the forested zone along the
Peace River and Bowlegs Creek.
o Stream channels would be reclaimed near present stream locations, and
banks of the stream channels would be revegetated to reduce erosion.
o The beneficiation plant site would be cleared and revegetated after
mining has been completed.
o Reclamation would be conducted as soon as areas become available.
Plant Construction and Operation
o Construction labor would be drawn from the local labor force to the
maximum extent possible.
o The new mining operation would be staffed primarily with employees
transferred from Mobil's existing work force in the area.
As stated earlier in this section, Mobil's proposed action is comprised of a
number of project subsystems linked so as to provide a total project capable
of meeting Mobil's production objectives. However, the methods proposed by
Mobil to achieve these objectives are not the only ones available. In the
following sections, various mining subsystem alternatives associated with the
2-17
-------
previously identified mining subsystems are described and evaluated, and the
environmentally preferred alternatives are identified. Under a given sub-
system heading (e.g., mining method, matrix transfer, etc.) a general descrip-
tion of each alternative is presented, followed by environmental considera-
tions pertaining to it. Where additional information is required to complete
the evaluation, technical and economic considerations are provided. The first
alternative discussed under each subsystem heading is Mobil's proposed action,
followed by other reasonable alternatives. Lastly, a summary comparison is
presented to identify the environmentally preferred alternative.
2.2 MINING METHOD ALTERNATIVES
The three potential mining methods that could be used at the proposed South
Fort Meade Mine site are dragline, bucket wheel and dredge mining. Any of
the three methods would disturb 15,194 acres of the 16,288-acre site, and
would include land clearing and open burning, drainage basin alterations, and
disruption of surface soils and the upper geologic strata. Associated with
the mining methods would be emissions of dust and fuel combustion, increased
surface runoff and erosion, disruption of stream flows and the Surficial Aqui-
fer, and the loss of vegetation, some wildlife, and most wildlife habitat in
the mine area. These common impacts cannot be avoided with any of the surface
mining methods. There are, however, specific advantages and disadvantages for
the three alternatives as presented in the following discussion.
2.2.1 DRAGLINE MINING (MOBIL'S PROPOSED ACTION)
2.2.1.1 General Description
Mobil proposes to use dragline mining as conventionally practiced in the
Florida phosphate industry. Two large electric-powered walking draglines,
with bucket capacities of 45-cubic yards each, would be used to sustain an
average annual production rate of 3.4 million tons. At this production rate,
approximately 530 acres per year would be mined. A 50-acre parcel would be
cleared ahead of each dragline. The walking dragline is a mobile unit that
removes the matrix efficiently and maneuvers well. Annual energy requirements
for the dragline are estimated at 1,650 kW for Phase 1 (one dragline) and
3,300 kW for Phase II (two draglines).
Mobil proposes to use pocket toe-spoiling as a leach zone management tech-
nique. The draglines would selectively strip and place the final bucket of
2-18
-------
overburden (the last six feet) in a pocket at the bottom of the mining cut,
subsequently covering the material with overburden spoils. This technique
confines the distribution of potential leach zone material to a level below
its in-situ location.
Operating constraints require a relatively dry pit for safety and optimum
matrix recovery. To attain the required dry condition, dewatering of the
Surficial Aquifer would be necessary, temporarily lowering water table levels
adjacent to the pit. To minimize the drawdown influence, Mobil proposes to
utilize perimeter rim ditches for recharge at property boundaries and at
designated sensitive areas.
To gain access to mining parcels north of Bowlegs Creek, a dragline crossing
would be located at an existing ford (Figure 2.1-A). The stream is scheduled
to be crossed in 1999 and again in 2002, with both crossings timed to occur
during low flow conditions. Woody vegetation in the corridor to the Bowlegs
Creek crossing would be cleared to about twice the width of the dragline. A
culvert would be placed in the stream with earth backfilled around the
culvert. After each crossing, grass cover would be established in the cleared
corridor to prevent erosion and runoff. After the second crossing in 2002,
the culvert would be removed and the stream channel re-established. Planting
of tree species characteristic of wetlands would supplement the grass cover in
the corridor area.
2.2.1.2 Environmental Considerations
Environmental Advantages: Leach zone management can be conducted with the
dragline mining method, thereby reducing the radiation levels in the soils of
the reclaimed areas. Draglines are efficient users of energy (8.5 kWh/ton
product) and an efficient recovery of phosphate matrix (85 to 87 percent) can
be realized. The mobility of the dragline allows mining around odd-shaped
boundaries and preserved areas.
Environmental Disadvantages: The required dewatering of the mine pits would
lower the water table level in the Surficial Aquifer (drawdown of one foot is
expected 115 feet from the perimeter of the open pit) and reduce natural
recharge by about 0.1 inch per year over the total project site. Dragline
2-19
-------
mining would also create a very uneven spoiling pattern, sometimes called wind-
rows. The creation of such windrows would require that heavy equipment be uti-
lized in reclamation to create a more uniform topography. Such leveling would
require the burning of fuel (in heavy equipment), resulting in increased air
pollutant levels (i.e., from combustion products).
2.2.2 BUCKET WHEEL EXCAVATION
2.2.2.1 General Description
A bucket wheel excavator is a large rotating wheel with fixed buckets attached
on its periphery. The bucket wheel excavator digs and cuts, discharging the
material onto an associated conveyor belt system. The main features of bucket
wheel excavators are continuous excavation of material and uninterrupted dis-
charge onto a conveyor system. They are generally equipped with crawlers to
provide mobility, allowing continuous use on various working levels.
Mining Mobil's South Fort Meade phosphate deposit would require a total of
four bucket wheel excavators. The excavators would be paired together and
would mine at two separate locations, in much the same sequence as the drag-
line operation. One excavator would strip overburden while the other would
mine the matrix. Compared with draglines of equal output, the bucket wheel
excavator is physically smaller because it is a continuous excavator. A
bucket wheel excavator equivalent to a 45-cubic yard dragline would be equip-
ped with 0.9 to 1.5-cubic yard buckets, depending on the number of buckets,
wheel diameter, cutting speed and other parameters.
Bucket wheel excavators are efficient energy users due to uniform power load-
ing and lower instantaneous power demands. As more difficult to excavate
material is moved, however, the efficiency decreases. Leach zone management
can be accomplished with bucket wheel excavators. The bucket wheel mining
method would require a larger cleared area ahead of the mining operation than
the dragline method. Totally dry pit conditions are necessary to prevent high
wall failure and to obtain structural stability. During the rainy season, the
increased moisture content in the matrix and water in the pit may be difficult
to control.
2-20
-------
2.2.2.2 Environmental Considerations
Environmental Advantages: Bucket wheel excavators are lower energy users than
draglines of equivalent size due to uniform power loading and lower instan-
taneous power demands. However, the energy efficiency advantage is partially
off-set because four bucket wheel units are required to accomplish the same
mining rate as two dragline units. The equipment can be operated to achieve
leach zone management similar to that with the dragline, thereby reducing sur-
face radiation levels in reclaimed areas.
Environmental Disadvantages: Bucket wheel mining would require a larger
cleared area than the dragline method, with correspondingly greater fugitive
dust emissions. Mining with a bucket wheel would require additional handling
of the overburden through conveyors which could potentially increase fugitive
dust and would generate greater noise levels than the dragline mining method.
Greater dewatering of the Surficial Aquifer would be required around the mine
pit to maintain a totally dry pit condition.
2.2.2.3 Technical Considerations
The bucket wheel mining method requires a totally dry pit because the equip-
ment is located in the pit. If dry pit conditions are not maintained, high
wall failures could occur in the pit, creating a safety risk and the potential
loss of equipment. The matrix must be dry to support the bucket wheel unit.
During the rainy season, additional dewatering of the matrix and the pit would
be necessary to operate the bucket wheels. The matrix contains clay which
often has sticky characteristics. The bucket wheel mechanism may not be able
to handle this material very effectively. If the buckets do not empty, the
mining rate would be reduced and energy consumption would increase.
2.2.3 DREDGE MINING
2.2.3.1 General Description
The basic dredge design consists of equipment mounted on a barge for floating
on water and moving over the material to be excavated. The excavating part of
the dredge is generally supported on a boom at the forward end. Several
spuds, or retractable anchor posts, are located on the aft end of the dredge
to hold it in a stable position.
2-21
-------
The cutterhead pipeline dredge is thought to be the most appropriate dredge
for application in a Florida phosphate mining operation due to the consistency
of the overburden. The unit is equipped with a rotating cutterhead surround-
ing the intake end of the suction pipe. At least two large capacity electric
dredges would be required for the South Fort Meade Mine: one to strip the over-
burden and one to mine the matrix. The overburden dredge would excavate and
pump overburden material to designated settling areas for dewatering, and
water decanted from the overburden slurry would flow back to the dredge pond
to be recirculated. The matrix dredge would excavate and pump the phosphate
matrix in a slurry form (similar to the dragline operation) to the beneficia-
tion plant. The dredge mining method requires about twice as much energy per
ton of phosphate product as the dragline mining method.
2.2.3.2 Environmental Considerations
Environmental Advantages: Fugitive dust emissions would be negligible with
this method since excavation is done underwater and overburden and matrix are
moved as slurry. Potential dust emissions would be further reduced by the
flooding of the cleared acreage. Because of the flooding of the mine pit to
support the dredge, there would also be no dewatering effects on the Surficial
Aquifer during the removal of overburden.
Environmental Disadvantages: Leach zone management cannot be achieved with
this method. This would result in greater surface radiation levels in
reclaimed areas as compared to the other mining methods incorporating leach
zone management.
Slurrying the overburden during dredging would result in the loss of water
with the overburden clays, increasing the volume of required clay settling
areas and makeup water requirements. The dredge method does not require the
lowering of the water table during the mining of overburden; however, the
water level must be lowered to approximately 25 feet below grade to mine the
phosphate matrix. The dredge operation would increase the concentration of
total suspended solids, organic material, and inorganic material in the dredge
pool water. This water could degrade the quality of the water in the recircu-
lation system, the water discharge and the Surficial Aquifer. The dredge
would also use more energy than either the bucket wheel or dragline (about
twice as much as the dragline).
2-22
-------
Environmental Disadvantages: The use of a conveyor transport system would
cause minor increases in particulate levels from fugitive dust emissions. The
corridor requirements for the conveyor would be larger than for the pipeline
method, resulting in increased disturbance to wildlife and vegetation on
unmined areas. The conveyor belt system would generate greater noise levels
(70 dBA could occur at 175 feet) than the pipeline transfer system. Energy
requirements for the conveyor belt and support equipment to move the matrix
from the mine pit to the conveyer belt hopper would be comparable to the pipe-
line transfer method. Greater spillage of material would be expected due to
the start-and-stop motion of the conveyor belt.
2.3.2.3 Technical Considerations
A conveyor belt system has distinct operation and maintenance problems when
applied to on-stream phosphate ore production. Conveyor belt systems are de-
signed to transport a dewatered and sized material; however, phosphate ore is
unsized and variable in moisture content. Conveyor systems require a con-
trolled feed rate to maintain a continuous, even flow of material on the belt
to match design rates. The dragline operates simultaneously as a stripping
and mining machine resulting in irregular flow cycles to the dump hopper.
Therefore, it would be necessary to stack the mined ore along the surface of
the mining cut. The ore would be rehandled by front-end loaders or a small
bucket wheel excavator and transferred to a centrally located hopper position.
The matrix would then be transferred on an apron feeder onto the conveyor belt
to be transported to the beneficiation plant. At the plant the ore would be
deposited in a sump, slurried with approximately 19,000 gpm of high pressure
water and pumped to the top of the washer for processing. The conveyor system
would not be as mobile as the pipeline system.
Two independent 36-inch conveyor systems would be required to transfer the ore
from Mobil's two mining areas to the beneficiation plant. Energy requirements
for the conveyor belt system would be 11.2 kWh/ton. The energy requirements
for the additional equipment needed to move the matrix from the mining area to
the conveyer belt hopper would be 0.4 gal fuel/ton product (equivalent to 6.3
kWh/ton product). Therefore, the combined energy requirements for the con-
veyor system and the support equipment would amount to approximately 17.5
kWh/ton product.
2-25
-------
2.3.3 TRUCK TRANSFER
2.3.3.1 General Description
Matrix transfer by diesel engine truck could be accomplished during Phase I
with 25-ton capacity trucks making 820 round trips per day. During Phase II,
1,640 truck trips per day would be necessary using trucks with a 25-ton capa-
city. Transferring matrix by truck would require the construction and mainte-
nance of roadbeds from the mining area to the plant. The truck transfer
method would require 1.2 gal fuel/ton product (equivalent to 19 kWh/ton pro-
duct). At the plant, matrix would be dumped and/or washed out of the trucks
and, as with conveyor transport, mixed with approximately 19,000 gpm of re-
cycle water before further processing.
2.3.3.2 Environmental Considerations
Environmental Advantages: When sufficient freeboard is left during loading,
the truck transfer method would have the least potential for spillage into
surface waters. This transfer method would also eliminate the need for 480
gpm of pump seal water.
Environmental Disadvantages: Energy requirements for the truck transfer
method would be greater than the pipeline or conveyor system transfer methods.
The construction, maintenance and use of haul roads would cause the most dis-
turbance to wildlife and vegetation. Truck transfer would generate the higher
noise levels of the three transfer methods and the greatest amounts of air
emissions such as fuel exhaust and fugitive dust.
2.3.4 SUMMARY COMPARISON
Energy consumption and air emissions are primary disadvantages to truck trans-
port. Secondary handling requirements offset any energy savings of the con-
veyor as compared to the pipeline, and difficult technical problems may
preclude its feasibility at the present time. Therefore, the environmentally
preferred alternative is pipeline transfer of matrix.
2.4 MATRIX PROCESSING ALTERNATIVES
Processing is the application of beneficiation techniques to the matrix after
it is mined and transported to the plant. At the plant, the phosphate is
2-26
-------
separated from the waste materials (sand tailings and clays) upgrading the
phosphate. Mobil proposes to use conventional beneficiation techniques as
they are currently practiced throughout central Florida. A processing alterna-
tive for the South Fort Meade Mine would be the use of dry separation.
2.4.1 CONVENTIONAL BENEFICIATION (MOBIL'S PROPOSED ACTION)
2.4.1.1 General Description
The processing of phosphatic ore involves a number of steps, each with the
purpose of separating phosphate rock from the associated organics and gangue
minerals (limestone cobbles, quartz sand and a mixture of clay minerals). The
major unit processing operations at the South Fort Meade Mine would include
the washer, feed preparation, flotation, and wet rock product storage (Figure
2.4-A).
Washing Facilities: The ore slurry received at the washer by pipeline would
contain phosphate, clay and sand. The washer would separate the ore by
particle size into two components: large phosphatic pebble, and a mixture of
smaller sand, phosphate and clay (Figure 2.4-B). The washer process would
involve a number of steps: separating the oversized material, pulverizing the
oversized material, disaggregating the clays and phosphatic ore, and washing
and separating the pebble from the undersized material (waste clays and feed).
The pebble would then be routed to wet rock storage piles, and the undersized
material (commonly termed debris) would be routed to feed preparation for fur-
ther processing.
Feed Preparation: In the feed preparation process, undersized material from
the washing operation would initially be separated by hydro-cyclones into two
fractions: flotation feed and waste clay. The flotation feed would be
directed to the feed preparation area or stockpiled until required for further
processing. Waste clays would be pumped from the feed preparation area to
disposal sites. The feed from the hydro-cyclones would be separated into
fine, coarse and sizer rock feeds by hydro-sizers. The feed preparation area
would provide a limited amount of storage capacity and would deliver feed to
the flotation plant at a uniform rate. The conceptual plan for the feed pre-
paration process is shown in Figure 2.4-C.
2-27
-------
GENERALIZED PROCESS FLOW SHEET
MINE
AREA
ORE
SLURRY
CLAY
WASHER
PLANT
DEBRIS
WASTE
CLAY
SETTLING
AREA
DECANTED WATER
SAND
TAILINGS
DISPOSAL
FEED
PREPARATION
PEBBLE
PRODUCT
FEED
FLOTATION
PROCESS
CONCENTRATE
PRODUCT
WELL
FIELD
RECYCLED WATER
CLEAR
WATER
POOL
SOURCE: MOBIL
-------
FIGURE 2.4-B
WASHER PROCESS
ORE SLURRY FROM
MINING AREA
PULVERIZED MATERIAL
HAMMERMILL
SOURCE: MOBL
OVERSIZED
MATERIAL
SCREENS
LOG WASHER
SCREENS
UNDERSIZED MATERIAL
(DEBRIS) TO FEED
PREPARATION
(-1190 mterona)
PEBBLE PRODUCT
(1190 to 19.0OO microns)
2-29
-------
FIGURE 2.4-C
FEED PREPARATION PROCESS
DEBRIS FROM WASHER
(-1190 microns)
HYDRO-
CYCLONES
_ CLAY WASTE TO
SETTLING AREA
(-74 microns)
HYDRO-SIZER
SIZER ROCK
FLOTATION
FEED
(696 to 11 tO micron*)
COARSE
FLOTATION
FEED
(297 to 696 micron*)
FINE
FLOTATION
FEED
(74 to 297 micron*)
SOURCE: MOB*.
2-30
-------
Flotation: Both-single and double stage flotation methods would be employed
to concentrate the phosphate (Figure 2.4-D). Single stage rougher flotation
would be used to concentrate the sizer rock product, while double stage flot-
ation of the coarse and fine feed would be used to concentrate the phosphatic
sand. Rougher flotation would float the phosphatic particles from the sand
using fatty acid reagents. The rougher product would then be subjected to a
de-oil bath and would be routed to cleaner flotation. The cleaner flotation
would utilize amine reagents to float the remaining sand to achieve final con-
centration of the product. Reagents to be used in the flotation process are
#5 fuel oil, caustic, fatty acid, amine, kerosene, and sulfuric acid. The
final phosphate concentrate would be dewatered and held in storage bins prior
to transfer to rail cars for shipment to Nichols.
Waste Products^ The two waste materials separated from the phosphate during
washing and flotation are clays and sand tailings. Estimated waste quantities
would be approximately 132 million tons of clay and 158 million tons of sand
tailings. The waste clays would contain about 23 percent of the recoverable
phosphate (particle sizes less than 200 mesh) contained in the matrix that
state-of-the-art processing technology cannot recover. Approximately 12 per-
cent of the recoverable matrix phosphate would be lost with sand tailings.
Conventional beneficiation, therefore, would recover 65 percent of the recover-
able phosphate found in the South Fort Meade matrix. Mobil is pursuing a re-
search program to develop processing technology that would allow the recovery
of additional phosphate lost with the waste clays.
Bulk Chemical Storage: The flotation reagents would be stored on site in ver-
tical, cylindrical, steel tanks built on above-ground foundations in a diked
tank farm. Routine safety precautions would include thorough training of
operating personnel, allowing only authorized personnel to operate pumps,
valves and controls, lighting the tank farm area and periodic inspections.
The surface inside the diked area would be paved and sloped to direct any
spillage and/or runoff to a sump pump which would discharge to the flotation
plant.
Energy Requirements: Conventional beneficiation would require 12,100 kW dur-
ing Phase I, and 18,200 kW during Phase II.
2-31
-------
FIGURE 2.4-D
FLOTATION PROCESS
SIZER ROCK FEED
(696 to 119O microns)
ROUGHER
FLOTATION
CONCENTRATE
(696 to 119O microns)
COARSE FEED
(297 to 696 microns)
ROUGHER
FLOTATION
DE-OIL
BATH
CLEANER
FLOTATION
CONCENTRATE
(297 to 696 microns)
SAND
TAILINGS
(74 to 119O microns)
SOURCE: MOBfc.
2-32
FINE FEED
(74 to 297 microns)
ROUGHER
FLOTATION
DE-OIL
BATH
CLEANER
FLOTATION
CONCENTRATE
(74 to 297 microns)
-------
Environmental Control Measures: The production areas of the washing facili-
ties, feed preparation unit and flotation process would be individually paved,
curbed and sloped to contain any spillage, clean-up water and rainwater.
Water collected would be pumped back to its respective area. During plant
construction and operation, perimeter ditches would be used to collect runoff
from the plant area. Roads in the plant area will be paved prior to con-
struction to reduce particulate emissions.
2.4.1.2 Environmental Considerations
Environmental Advantages: Conventional benefication processing would not have
significant air emissions and would not contribute noise to the off-site envi-
ronment. Wet processing of the slurried matrix has little potential for gener-
ation of airborne radioactivity associated with particulates. Conventional
beneficiation processing would recover 65 percent of the recoverable phosphate.
Environmental Disadvantages: Conventional beneficiation would require large
amounts of water: 130.2 mgd of recycled water and 15.7 mgd of groundwater.
Withdrawing groundwater would lower the piezometric level of the Lower
Floridan Aquifer an average of 3.3 feet beneath the site.
Conventional processing generates clay wastes in a solution containing about
three to five percent solids. Disposal of these clays would require impound-
ments where the water can be decanted. The volume of clay generated and
amount of water entrapped in the clays would require the clay settling areas
to be diked above grade.
Conventional beneficiation requires the use of several reagents in the flota-
tion process. The reacted reagent would be discharged from the process with
the waste sand tailings and clays, and most of the reagents would adhere to
the clay particles. The discharge from the clear water pool would contain
trace amounts of the reagents and reacted reagent-sulfate compounds.
2.4.2 DRY SEPARATION
2.4.2.1 General Description
Dry separation is a process that involves drying, crushing and sizing of the
matrix. After drying with a rotary kiln and crushing with a hammermill, the
2-33
-------
matrix would be processed through several stages of air separation to separate
the pebble product from the finer materials. Additional phosphate product
would then be separated from the remaining material by an electrostatic separa-
tor. Less than half of the mined phosphate at the South Fort Meade site can
be separated through this processing method because the ore is primarily fines
and not pebble. Since the in-situ matrix in the South Fort Meade area con-
tains about 19 percent water, large quantities of fuel would be required for
the drying step.
2.4.2.2 Environmental Considerations
Environmental Advantages: Dry separation would not require significant water
usage, therefore, the piezometric level of the Lower Floridan Aquifer would
not be changed as a result of pumping groundwater. Waste material from the pro-
cess could be disposed of in below-grade areas.
Environmental Disadvantages: The dry separation process would create a signif-
icant source of SO- and NO emissions resulting from the burning of fuels to
C. A
dry the matrix. There would also be greater fugitive dust and noise levels
than through the conventional benefication process. The dry separation pro-
cess would have the potential for generating large amounts of clay and dust-
sized particulates which could lead to radiation exposure through inhalation.
The efficiency of recovery of phosphate by dry separation would be less than
by conventional beneficiation. Dry separation would consume considerably more
energy than conventional beneficiation.
2.4.4 SUMMARY COMPARISON
There are significant environmental disadvantages to both methods of proces-
sing. Conventional processing would utilize large quantities of water and
would generate waste clay that would have to be disposed of in above-grade
clay settling areas. Dry processing would create significant air emissions
and would consume large quantities of energy. Conventional benefication
recovers about 65 percent of the recoverable phosphate while the dry separa-
tion process recovers about 50 percent of the recoverable phosphate. The con-
ventional beneficiation process is considered to create slightly less environ-
mental impacts and is, therefore, the environmentally preferred method of
matrix processing.
2-34
-------
2.5 WASTE DISPOSAL ALTERNATIVES
Various alternatives have been considered to address the concerns of disposal
of waste clay from phosphate mining. At Mobil's South Fort Meade Mine the
matrix sand/clay ratio (1.2:1) is very low when compared to other phosphate
mining operations in the area (Table 2.5-1). This increases the quantity of
waste clay that must be disposed of in relation to the sand tailings. Mobil
evaluated thirty waste disposal techniques, and after considerable screening
and review with EPA, three main disposal concepts were selected for detailed
evaluation. These concepts included: 1) conventional waste clay and sand
tailings disposal as currently practiced by the phosphate industry, 2) mixing
sand tailings with thickened clay wastes, and 3) mixing overburden sand and
sand tailings with clay wastes. When the three waste disposal concepts were
combined in alternative disposal schemes, the following four waste disposal
cases were developed for final consideration: 1) conventional clay settling,
2) sand/clay cap, 3) sand/clay mix, and 4) overburden/clay mix. Mobil's pro-
posed action is the conventional clay settling case and is described in
Section 2.5.1. Each alternative waste disposal method is addressed in the
following sections.
2.5.1 CONVENTIONAL CLAY SETTLING CASE (MOBIL'S PROPOSED ACTION)
2.5.1.1 General Description
Mobil proposes to use conventional methods for disposal of waste sand tailings
and clay. Sand tailings would be principally used to backfill mined areas
(5,034 acres). Waste clays would be contained behind earthen dikes
constructed on natural ground (1,320 acres) or constructed in mined areas
(8,363 acres). Average dike heights would be 38.7 feet above grade. The
estimated power consumption for pumping waste sand and clays would be 1,004 x
106 kWh over the life of the mine. A discussion of disposal methods for clay,
sand tailings, and overburden are presented below for the conventional clay
settling case.
Waste Clay Disposal: Substantial quantities of water (11.6 mgd) would be en-
trained in the waste clays, increasing their volume and requiring considerable
storage area for settling basins. The conventional disposal plan would dis-
charge waste clays at three to five percent solids behind earthen dikes for
consolidation and water decanting. Two to four years after the pond is taken
out of service, the clay wastes would consolidate to about 20 percent solids.
2-35
-------
TABLE 2.5-1
SUMMARY OF MATRIX SAND/CLAY RATIOS
Company
Mine
Matrix
Sand/Clay
Ratios
Grace
Estech
Beker
AMAX
Borden
Brewster
CF Industries
Farmland
Mississippi Chemical
Mobil
Four Corners 4.5:1
Duette 4.2:1
Manatee 4.0:1
Pine Level 3.75:1
Big Four 3.2:1
Ft. Lonesome 2.5-3:1
Hardee Co. 2.6:1
Hardee 2.5:1
Hardee Co. 2.2:1
South Fort Meade 1.2:1
SOURCE: Ratios calculated from published information including DRI
Applications.
2-36
-------
During waste disposal operations clarified water would be drawn off through
the spillways by gravity and would be recirculated into the plant system
(Figure 2.5-A).
Figure 2.5-B shows the locations of the clay settling areas proposed for the
South Fort Meade Mine. Approximately 328,000 acre-feet of waste clays would
be stored in a total of 9,683 acres. The initial waste clay settling areas,
CS-1 and CS-2, would be built on unmined ground with dikes constructed of
overburden material. These settling areas would contain the waste clays
generated during the first five years of mining. After construction of CS-1
and CS-2, all other waste disposal areas would be constructed on mined land.
All the clay wastes generated during the life of the mine would be contained
in Areas CS-1 through CS-14. However, a portion of the clay wastes allocated
to Area CS-14 would be transferred to CS-15 to provide below-grade fill for
the last mining area on the site. This low level fill would provide a shallow
aquatic environment for eventual reclamation as a wetland. No dike is planned
for CS-15 since the fill level would be approximately three feet below natural
grade. A portion of the clay fill for CS-15 would be obtained by flowing clay
slurry through CS-14 until that area approaches natural grade. The transfer
of clay slurry from CS-14 to CS-15 would continue by pumping clays out of
CS-14 until the clay level in CS-14 averages three feet below existing grade.
This would leave both Areas CS-14 and CS-15 approximately three feet below
grade for reclamation as wetlands.
After the areas are allowed a period of consolidation, sand tailings would be
used to cap all the interior of Areas CS-1 and CS-2 to an average depth of two
feet, and a portion of the interior of Areas CS-4, CS-5, CS-6 and CS-7 to an
average depth of 8 to 10 feet. The sand cap would enhance the structural
stability of the reclaimed surface. Acreages, dike heights, fill levels and
reclaimed elevations for all clay settling areas are shown in Table 2.5-2.
A flow through settling technique is commonly used with conventional clay
settling and would be implemented at the South Fort Meade mine. This
technique is generally utilized for clay settling basins that are located
adjacent to each other. The procedure consists of introducing the waste clay
stream into a series of clay settling basins instead of a single basin. The
2-37
-------
i i
r
'
WASTE CLAY SETTLING METHOD
WASTE CLAY
SLURRY (3-6%
SOLIDS)
FROM
BENEFICIATION
PLANT
DECANTED
WATER
TO
RECIRCULATION
SYSTEM
SOURCE: MOBIL
NOTE: NOT TO SCALE
CD
73
m
> i
I
,-
i
-------
CONVENTIONAL WASTE DISPOSAL CASE
OUT PARCELS
(NOT OWNED BY MOBU
;;:! CLAY SETTUNQ WITH
- SAND TALING CAP
03 CLAY SETTUNQ
OF OVERBURDEN FU.
TF SAND TAUNQ FLL
WITH OVERBURDEN CAP
OF-6
OF-1
SOURCE: MOBIL
-------
TABLE 2.5-2
ACREAGES, DIKE HEIGHTS, FILL LEVELS AND RECLAIMED ELEVATIONS
FOR CLAY SETTLING AREAS
(Conventional Case)
Elevation Relative To Existing Grade
Area
CS-1
CS-2
CS-3
CS-4
CS-5
CS-6
CS-7
CS-8
CS-9
CS-10
CS-11
CS-12
CS-13
CS-14
CS-15
Total
Total
Acreai
780
540
840
385
300
750
735
620
400
1,020
690
520
590
520
993
9,683
Sand
Capped
jŁ Acreage
653
427
--
60
60
143
146
..
--
--
1,489
Uncapped
Acreage*
127
113
840
325
240
607
589
620
400
1,020
690
520
590
520
993
8,194
Dike
Height
(ft.)
45
45
45
45
45
35
35
35
35
35
35
35
40
25
0
Clay
Fill
Level
(ft.)
40
40
40
40
40
30
30
30
30
30
30
30
35
-3
-3
Approximate
Reclaimed
Elevation
(ft.) for
Capped
Portion
45
45
45
45
35
35
--
--
--
--
__
Approximate
Reclaimed
Elevation (ft.)
for Uncapped
Portion
--
34
34
34
25
25
25
25
26
25
25
30
-4
-4
* Uncapped acreage Includes both dike acreage and interior acreage without a sand cap.
Average daw height = 38.7 feet
SOURCE: MOBIL
2-40
-------
advantages of the flow through settling technique are improved water clarifi-
cation, clay compaction, and water management. The specific filling schedule
and active settling acreage for the conventional waste disposal case using the
flow through settling technique are shown in Table 2.5-3.
Sand Tailings Disposal: Sand tailings would be used as backfill in mined
areas, in the construction of earthen dikes and for capping material. Approx-
imately 76 percent of the sand tailings generated during the life of the mine
would be utilized in tailings fill areas. There would be 23 tailings fill
areas totaling 5,034 acres (Figure 2.5-B). Table 2.5-4 summarizes the acre-
ages of these areas.
Sand tailings fill areas would receive slurried sand tailings pumped from the
processing plant to mined areas, filling voids between the piles of overburden
stacked during mining. The decanted water from the sand tailings would be
directed to the water recirculation system. Overburden extending above the
level of the sand tailings would be graded, bringing the mined land to approx-
imate natural grade with an average overburden cap of two feet. About five
million tons of sand tailings would be used as fill material in the construc-
tion of earthern dikes for the disposal of clay wastes. Approximately 32.5
million tons of sand tailings would be used as a cap on the clay settling
areas.
Overburden: Overburden would be used to backfill mined lands, for construc-
tion of waste clay storage areas and for capping sand tailings fill areas.
Eight overburden fill areas totaling 308 acres are included in the waste dis-
posal plan (Figure 2.5-B).
2.5.1.2 Environmental Considerations
Environmental Advantages: The conventional clay settling case alternative
provides the greatest potential for future recovery of recoverable phosphate
when advanced technology is developed. The clay impoundments (9,683 acres)
would contain phosphate in the most concentrated, uncontaminated form (tons of
recoverable phosphate per ton of waste). This waste disposal method also
consumes the least energy of all the alternatives. Clay settling basins are
self-sealing, preventing seepage to the Surfical Aquifer of water containing
2-41
-------
TABLE 2.5-3
ACTIVE SETTLING ACREAGE OF ABOVE-GRADE BASINS
(Conventional Clay Settling Case)
Settling
Area
CS-1*
CS-2*
CS-3
CS-4**
CS-5**
CS-6**
CS-7**
CS-8**
CS-9
CS-10
CS-11
CS-12
CS-13
Acreage
780
540
840
385
300
750
735
620
400
1,020
690
520
590
Begin Clay
Fill
(Mine Year)
1
3
3
8
9
10
12
14
15
16
18
20
21
Complete
Clay Fill
(Mine Year)
4
4
8
15
15
15
15
15
16
18
20
21
23
Active Settling
Acreage
780
1,320
840
385
685
1435
2170
2760
400
1020
690
520
590
* CS-1 and CS-2 would be operated by the flow through settling technique.
**CS-4, CS-5, CS-6, CS-7, and CS-8 would be operated by.the flow through
settling technique, which means that water and unconsolidated clays flow
throughout the system from the beginning of clay fill for an individual
settling area until the completion of clay fill in the last basin within
this group (e.g., CS-4 is active in mine years 8-15 and CS-6 in mine years
10-15).
SOURCE: MOBIL
2-42
-------
TABLE 2.5-4
SAND TAILINGS FILL ACREAGE
(Conventional Case)
Area
TF-1
TF-2
TF-3
TF-4
TF-5
TF-6
TF-7
TF-8
TF-9
TF-10
TF-11
TF-12
TF-13
TF-14
TF-15
TF-16
TF-17
TF-18
TF-19
TF-20
TF-21
TF-22
TF-23
Acreage
20
211
73
131
135
265
315
40
286
300
135
210
20
102
365
760
214
80
147
466
120
230
409
Total 5,034
NOTE: Total acreage includes setbacks from public roads and
property boundaries which will be disturbed but not mined.
SOURCE: MOBIL
2-43
-------
contaminants from mining and processing. The conventional clay settling case
is a proven operating technique that presents the least process risk.
Environmental Disadvantages: This case would have the greatest acreage of
above-grade clay settling basins (8,170 acres) with the highest average dike
height (38.7 feet). Approximately 11.6 mgd of water would become entrained
with the waste clay and would require a long period of time to dewater. The
clay basins are expected to reach 22 percent solids after five years of de-
watering. The conventional case has the greatest amount of active above-grade
clay settling area (2,760 acres) at a given time. This case, therefore, has
the highest probability for dike failure and a resulting spill.
2.5.2 SAND/CLAY CAP CASE
2.5.2.1 General Description
The following four general types of waste disposal areas are included in the
sand/clay cap alternative waste disposal case:
o Above-grade clay settling areas with a sand/clay mix cap (7,580
acres)
o Above-grade clay settling areas with an overburden cap (590 acres)
o Below-grade clay settling areas with partial overburden cap
(1,513 acres)
o Sand tailings fill areas with an overburden cap (5,079 acres)
o Overburden fill areas (308 acres)
The distribution of these areas on the site is shown in Figure 2.5-C. The
average dike height for this plan is 36.7 feet. The estimated power consump-
tion for pumping waste sand and clay in this waste disposal case would be
1,253 x 106 kWh over the life of the mine.
Clay Settling Areas: Fourteen areas would receive clay wastes during the life
of the mine. Proposed acreages, dike heights, fill.levels, and reclaimed ele-
vations are summarized for all clay settling areas in Table 2.5-5. Two set-
tling areas, CS-1 and CS-2, would be constructed on unmined ground to receive
all the clay wastes generated during the first four or five years of mine
life. By year 5, Area CS-3 would have been constructed in the initial mining
area and would begin to receive clay wastes. Areas CS-4 through CS-13 would
then be used in numerical sequence to contain clay wastes. Flow through
2-44
-------
WASTE DISPOSAL AREAS - SAND/CLAY CAP
OUT PARCELS
(NOT OWNED BY MOBU
UNDISTURBED AREAS
OVERBURDEN
SAND/CLAY
CLAY SETTUNQ
OVERBURDEN HLL
SAND TAIJNG RLL
WITH OVERBURDEN CAP
OF-6
OF-1
SOURCE: ZELLAR8-WILLIAMS
-------
TABLE 2.5-5
CLAY SETTLING AREAS
(Sand/Clay Cap Case)
Elevation Relative To Natural Grade
Area
CS-1
CS-2
CS-3
CS-4
CS-5
CS-6
CS-7
CS-8
CS-9
CS-10
CS-11
CS-12
CS-13*
CS-14*
Total
Total
Acreage
780
540
840
385
300
750
735
620
400
1,020
690
520
590
1.513
9,683
Dike
Height (ft.)
45
45
45
35
35
35
35
35
30
30
35
35
32
0
Fill
Level (ft.)
40
40
40
30
30
30
30
30
25
25
30
30
27
-3
Approximate
Reclaimed
Elevation (ft.)
34
34
31
23
23
23
23
23
19
18
23
23
1
-5
* Areas capped with overburden; all others capped with sand/clay mix
SOURCE: ZELLARS-WILLIAMS
2-46
-------
settling cannot be used with the sand/clay cap disposal method. In order to
place the sand/clay cap over the clay settling areas in a timely fashion, the
basins must be taken out of service after the initial fill and actively dewa-
tered to develop a crust. Table 2.5-6 shows the filling schedule for the
above-grade clay settling basins, their acreages and the mining years during
which the respective basins are active.
After a period of consolidation, Areas CS-1 through CS-12 would receive a
second fill and cap of sand/clay mix at a ratio of 4:1. A minimum consoli-
dation period of three years would be allowed between final clay fill and
placement of the sand/clay cap. The subsidence in the clay fill during this
period determines the exact depth of the cap which would range from four to
six feet. The sand/clay cap would extend over approximately 95 percent of the
total surface of the area. The remaining five percent would be left uncapped
in order to create shallow depressions suitable for reclamation as wetlands.
The sand/clay mix would be made by mixing prethickened clays with sand tail-
ings. Area CS-3 would be used throughout most of the mine life for thickening
the clays prior to mixing with sand. Clay slurry would enter this area at
three to five percent solids. When the clays were consolidated to approx-
imately 15 percent solids, the thickened clays would be dredged out for mixing
with a suspension of sand tailings.
An overburden cap is planned for Area CS-13. The clay level in this area
would remain approximately 10 feet above grade following dredge removal of
clay fill to Areas CS-3 and CS-14. This level of fill would leave sufficient
material in the retaining dike and protruding spoil piles to provide a partial
overburden cap averaging one foot thick over the area.
Sand Tailings Fill Areaj^: Approximately 76 percent of the sand tailings gen-
erated during the life of the mine would be utilized in tailings fill areas.
Twenty-four tailings fill areas, totaling 5,079 acres, are included in this
case; acreages for these areas are summarized in Table 2.5-7. The areas would
be filled with sand tailings to near natural grade. The overburden spoil
piles would then be graded over the fill to achieve an overburden cap averag-
ing approximately two feet in depth.
2-47
-------
TABLE 2.5-6
ACTIVE SETTLING ACREAGE OF ABOVE-GRADE BASINS
(Sand/Clay Cap Case)
Settling
Area
CS-1
CS-2
CS-3*
CS-4
CS-5
CS-6
CS-7
CS-8
CS-9
CS-10
CS-11
CS-12
CS-13
Acreage
780
540
840
385
300
750
735
620
400
1,020
690
520
590
Begin Clay
Fill
(Mine Year)
1
1
5
8
10
11
13
15
16
17
19
21
22
Complete
Clay Fill
(Mine Year)
4
6
8
10
11
13
15
16
17
19
21
22
27
Active Settling
Acreage
780
1,320
840
1,225
1,140
1,590
1,575
1,460
1,240
1,860
1,530
1,360
590
* CS-3 would be used as a dredge basin and alternately filled and emptied
during mine years 5 through 27.
SOURCE: ZELLARS-WILLIAMS
2-48
-------
TABLE 2.5-7
SAND TAILINGS FILL AREAS
(Sand/Clay Cap Case)
Area Total Acreage
TF-1
TF-2
TF-3
TF-4
TF-5
TF-6
TF-7
TF-8
TF-9
TF-10
TF-11
TF-12
TF-13
TF-14
TF-15
TF-16
TF-17
TF-18
TF-19
TF-20
TF-21
TF-22
TF-23
TF-24
Total
20
211
73
131
135
265
315
40
286
300
135
210
20
102
365
760
214
80
147
466
120
230
409
45
5,079
SOURCE: ZELLARS-WILLIAMS
2-49
-------
Overburden Fill Areas: Eight overburden fill areas totaling 308 acres and
consisting of relatively small, irregularly shaped parcels adjacent to waste
disposal dikes would be utilized in the sand/clay cap waste disposal case.
2.5.2.2 Environmental Considerations
Environmental Advantages: The average dike height of the above-grade settling
areas would be reduced two feet as compared to the conventional case. The
maximum active settling acreage is reduced (1,860 acres versus 2,760 acres for
conventional); therefore, the probability of a dike failure is least for the
sand/clay cap case. The clay waste would seal the above-grade basins and pre-
vent possible seepage of contaminants from the basins into the Surficial
Aquifer. This method of disposal would impound 93 percent of the waste clay
in an uncontaminated form that would allow recoverable phosphate reserves to
be mined and processed at a future date when advanced technology becomes avail-
able (0.35 tons of phosphate per ton of waste sand and clay). With the sand/
clay cap case, approximately 1,252 x 106 kWh of power would be required for
sand and clay pumping during the mine life. This is 25 percent greater than
the conventional clay settling case but considerably less than the other alter-
native. (See Table 2.5-11 for values.)
Environmental Disadvantages: This case would have only 8,170 acres of above-
grade clay settling basins (equal to the conventional case) and more than the
other two cases. Approximately 11.6 mgd of water would become entrained in
the waste clay and would require a long period of time to dewater. The
sand/clay cap method of waste disposal has not been practiced before and
would, therefore, represent some risk of being unsuccessful.
2.5.3 SAND/CLAY MIX CASE
2.5.3.1 General Description
The sand/clay mix waste disposal method would involve mixing gravity thickened
clays with dewatered sand tailings and depositing the mixture in mined areas
for consolidation and stabilization. The clays would be pumped from the set-
tling/thickening areas to the mix area and disposal sites. Sand to clay
ratios of 2:1 have been shown to be the minimum ratio to achieving significant
consolidation benefits. The high clay content in the South Fort Meade Mine
matrix would preclude the use of sand/clay mix techniques of waste disposal
2-50
-------
for the whole site. A combination of sand/clay mix areas and conventional
sand and clay disposal areas would be required in disposing of the wastes.
The following six general types of waste disposal areas are included in the
sand/clay mix case:
o Clay settling areas (3,737 acres)
o Sand tailings fill areas (3,020 acres)
o Sand/clay mix areas (3,512 acres)
o Clay settling areas with a sand/clay mix cap (3,185 acres)
o Graded spoil (838 acres)
o Overburden fill areas (733 acres)
The distribution of these areas on the site is shown in Figure 2.5-D. The
average dike height for this plan is 35 feet. The estimated power consumption
for pumping waste sand and clay in this waste disposal case would be 1,358 x
106 kWh over the life of the mine.
Clay Settling Areas: A total of 11 areas would receive clay wastes during the
life of the mine. Acreages, dike heights, fill levels, and reclaimed eleva-
tions are summarized for the clay settling areas in Table 2.5-8. Two settling
areas, CS-1 and CS-2, would be constructed on unmined ground to receive all
the clay wastes generated during the first four years of mine life. Beginning
in year 5, a portion of clays would be routed to the two dredge ponds (DP-1
and DP-2) with the excess going to CS-2. When the sand/clay mix method be-
comes operational in year 6, Areas CS-2 through CS-9 would be used in sequence
to contain the clay wastes generated in excess of the sand/clay mixing capac-
ity of the mine.
A second stage fill of clay settling Areas CS-1 through CS-8 would be employed
to fully utilize the storage capacity available. As the clays consolidate,
the spillway overflow levels would be continually lowered to keep the areas
drained. The subsidence in fill level would make additional storage volume
available. Areas CS-3 through CS-8 would receive a second stage fill of five
feet of sand/clay mix (2:1). Areas CS-1 and CS-2 would receive clay alone as
the second stage fill.
2-51
-------
WASTE DISPOSAL AREAS SAND/CLAY MIX
LEGEND
OUT PARCELS
(NOT OWNED BY MOB!)
CLAY SETTLING
SAND/CLAY MIX
TAILINGS FILL
OVERBURDEN FILL
GRADED SPOILS
DREDGE POND
SAND CLAY
FINAL RECLAIMED
LAND FORM
SOURCE: ZELLAR3-WILLIAMS
-------
TABLE 2.5-8
CLAY SETTLING AREAS
(Sand/Clay Mix Case)
Elevation Relative To Natural Grade
Area
CS-1
CS-2*
U o4^,
CS-4*
CS-5*
CS-6*
CS-7*
CS-8
CS-9
CS-10
DP-1
Total
Total
Acreage
6,922
Dike
Height (ft.)
48
48
48
48
48
48
48
35
20
0
37
Fill
Level (ft.)
43
43
43
43
43
43
43
30
-2
-3
10
Approximate
Reclaimed
Elevation (ft.)
38
38
35
35
35
35
36
25
-3
-4
7
* Capped with sand/clay mix
SOURCE: ZELLARS-WILLIAMS
2-53
-------
Area CS-10 would receive below-grade clay fill beginning in year 22 and con-
tinuing until year 27. No dike is planned for this area since the fill level
would be approximately 2.5 feet below natural grade. This area would provide a
shallow aquatic environment for reclamation as a wetland area.
Sand Tailings Fill Areas: Approximately 41 percent of the sand tailings gen-
erated during the life of the mine would be utilized in ten tailings fill
areas. Acreages and reclaimed elevations are summarized for the tailings fill
areas in Table 2.5-9. With the exception of TF-9, all the areas would be
filled with sand tailings to within two feet of natural grade. The overburden
spoil piles would then be graded over the fill to achieve an overburden cap
averaging two feet in depth. Area TF-9, north of Bowlegs Creek, would be
filled with approximately five feet of sand tailings. When capped with over-
burden, this level of fill would result in a reclaimed land surface that would
be below natural grade but above the water table.
Sand/Clay Mix Areas: Approximately 35 percent of the total waste clay and
59 percent of the total sand generated during mine life would be mixed at a
2:1 sand to clay ratio and placed either in sand/clay mix areas or used to cap
clay settling areas (Table 2.5-8). Twelve sand/clay mix areas totaling 3,512
acres and six clay settling areas capped with sand/clay mix totaling 3,185
acres would be developed with this waste disposal method.
The first sand/clay mix areas are scheduled to be filled in year 6 of the mine
life. These areas would be reclaimed as wetlands requiring them to be filled
only to near natural grade. They would be allowed to subside until year 8
when they would be filled again to capacity with sand/clay mix. The remaining
ten sand/clay mix areas would be designed to allow for subsidence to above
natural grade. Table 2.5-10 summarizes dike heights, original fill levels,
reclaimed elevations and acreages planned for the various sand/clay mix areas.
Dike heights of 20 feet are planned for the majority of the sand/clay mix
areas. Only three areas would have dike heights of 30 feet or higher. Eleva-
tions of reclaimed sand/clay landfills are projected to be at approximately
2-54
-------
TABLE 2.5-9
SAND TAILINGS FILL AREAS
(Sand/Clay Mix Case)
Relative
Area
TF-1
TF-2
TF-3
TF-4
TF-5
TF-6
TF-7
TF-8
TF-9
TF-10
Total
Total
Ac reage*
20
218
124
270
306
286
311
300
1,050
135
3,020
Reclaimed Elevation
To Natural Grade (ft.)
0
0
0
0
0
0
0
0
-5
0
* Total acreage includes setbacks from public roads and property
boundaries which will be disturbed but not mined.
SOURCE: ZELLARS-WILLIAMS
2-55
-------
TABLE 2.5-10
DIKE HEIGHTS AND ELEVATIONS - MIX AREAS
(Sand/Clay Mix Case)
Elevation Relative To Natural Grade
Area
M-l
M-2
M-3
M-4
M-5
M-6
M-7
M-8
M-9
M-10
M-ll
DP -2
Total
Acreage
102
58
160
245
425
360
160
440
410
330
500
322
Dike
Height (ft.)
0
0
35
20
20
20
20
30
20
20
20
37
Fill Level (ft.|
0
0
30
15
15
15
15
25
15
15
15
32
Approximate
Reclaimed
Elevation (ft.)
-4
-3
21
8
9
9
8
16
8
8
8
22
Total
3,512
SOURCE: ZELLARS-WILLIAMS
2-56
-------
eight feet above natural grade for the 20-foot diked areas and from 16 to 22
feet above grade for the areas with dikes 30 feet or higher.
Sand/clay mix at a 2:1 ratio would be used as a second stage fill and cap for
six clay settling areas. The depth of the sand/clay cap in these areas would
range from four to six feet. The second fill would utilize the waste storage
volume available and would also place sand/clay mix as the surface soil.
Graded Spoil Areas: Three areas totaling 838 acres would be reclaimed without
the use of backfill material. Areas GS-1, GS-2 and GS-3 would be graded to
prevent ponding of water and would be sloped to the south towards Bowlegs
Creek. Due to the rapid elevation changes, there would be sufficient slope to
allow the areas to drain towards Bowlegs Creek, even though the reclaimed area
would average 15 feet below natural grade.
Overburden Fill Areas: Twelve overburden fill areas totaling 733 acres are
included in the sand/clay mix waste disposal alternative. During the con-
struction of dikes the mining voids would be backfilled to near natural grade
with overburden material graded from spoil piles on site and transported from
adjacent mining areas.
2.5.3.2 Environmental Considerations
Environmental Advantages: This case would result in less above-grade clay
settling acreage than either the conventional or sand/clay cap cases. The
average dike height of the above-grade basins is least of all the cases. The
2,450 areas of active settling area is between that of the conventional clay
settling case and the sand/clay cap case. In the event of a dike failure the
sand/clay mix would not flow as rapidly or as far as the clay waste alone. The
addition of the sand to the clay wastes would improve the drainage charac-
teristics of the mix and the initial consolidation period for the sand/clay
mix areas would be shorter than for the conventional case.
Environmental Disadvantages: The sand/clay mix disposal case still results in
extensive above-grade clay settling acreage (4,505 acres). Power consumption
for pumping waste sand and clay would be 1,358 x 10 kWh, approximately 36
percent more than required for the proposed conventional case. Because of
2-57
-------
mixing the waste clays with sand, this method of disposal would require
greater effort to recover phosphate reserves at a future date when advanced
technology becomes available (0.26 ton of phosphate per ton of waste sand and
clay). The sand/clay mix method of waste disposal has not been practiced
before and would, therefore, represent some risks concerning results. These
risks would be approximately equal to those for the sand/clay cap case. The
probability for a dike failure occurring is second highest of all the cases.
2.5.4 OVERBURDEN/CLAY MIX CASE
2.5.4.1 General Description
Since sufficient sand tailings are not available from the matrix to accomplish
a 2:1 sand/clay mix ratio over the entire site, overburden sand could be used
as an additional source of sand to mix with the waste clay. The overburden
would be slurried and pumped to a field washer for screening and washing. The
recovered overburden sand would then be pumped to the mixing station where it
would be combined with thickened waste clay at a 2:1 sand to clay ratio for
final disposal. The overburden/clay mix and other waste disposal areas are
shown on Figure 2.5-E.
In order to determine the availability of overburden for use in the over-
burden/clay mixing scheme, information was analyzed from eight sample loca-
tions on the South Fort Meade site. The analysis indicated that the clay con-
tent of the overburden increases with depth. The upper five feet are rela-
tively low in clay content, ranging from one to five percent. The clay con-
tent increases at depths between 5 and 15 feet, coinciding with the presence
of hardpan and other clay layers. The hardpan contains substantially more
clay than the upper overburden horizon and is probably a less desirable source
of sand for mixing. The clay content continues to increase below the hardpan
as the phosphate zone is approached at depths of more than 15 feet. The upper
horizon above the hardpan unit represents the best source of available sand
within the overburden section.
Not all areas of the South Fort Meade Mine site are suitable or available for
overburden mining. Areas that could not be used include the following cate-
gories: areas required during the initial five years of mine life for opera-
tional considerations, areas committed to tailings backfill reclamation,
2-58
-------
CONCEPTUAL WASTE DISPOSAL AREAS - OVERBURDEN/CLAY MIX
A OlMPAHCElb (PKlvATtLY OWNLD)
SOURCE: STUDY DATA
OVERBURDEN MIXING
STATION
CLAY SETTLING
(BELOW GRADE)
CLAY SETTLING WITH
SAND/CLAY CAP
SAND/CLAY MIX OR
OVERBURDEN/CLAY MIX
TAILINGS FILL OR
OVERBURDEN FILL
UNDISTURBED AREAS
-------
environmentally sensitive areas, areas required during the sixth and seventh
years of mine life to permit overburden stockpiling, and areas too shallow for
practical removal by the earthmoving equipment. The total area available for
overburden mixing is about 2,560 acres (25 percent) of the mineable tract with
about 52 million tons of overburden available for mining/mixing. This amount
of overburden would in turn stabilize approximately 26 million tons of clay.
Therefore, enough overburden exists to reclaim 1,980 acres with the overbur-
den/clay mix technique.
Overburden Processing: The system required to recover the sand portion of the
overburden is similar to the system employed in mining and processing phos-
phate rock. As shown in Figure 2.5-F, a single dragline would deliver over-
burden to a wet pit for slurrying and hydraulic transport to a separate over-
burden washer. A series of screens would separate the recoverable sand from
clay and organic matter. Sand recovered by the washer would then be pumped to
a mix station where it would be combined with waste clay at a 2:1 ratio and
then deposited for final settling. The clay wastes and organic matter would
be consolidated by passing the material through a dewatering cyclone that re-
moves excess water. The consolidated material would then be pumped to a
dredge pond for thickening and then on to final disposal.
Because the matrix mining and overburden mining systems would share a common
source of recycle water, contamination of products from each system would
occur. While contamination of the product from one system by the product of
the second can be avoided, the necessity of sharing a common source of water
could result in contamination of the clear water supply feeding the beneficia-
tion plant. Organic material and clay wastes separated at the overburden
washer would be introduced into the dredge pond with the clay wastes and mixed
with sand prior to final disposal. Water decanted from the sand/clay mixture
after final disposal could contain substantial amounts of organic matter,
which would then be returned to the clear water pool. Therefore, this waste
disposal case would probably necessitate treatment of the process water used
at the beneficiation plant.
Waste Disposal Details: The waste clays generated during the initial four
years of mining and processing would be routed to settling areas CS-1 and
2-60
-------
OVERBURDEN/CLAY MIXING CONCEPT
Recycle Water
no
Sand Tailing*
Clear Water
Circulation
System
Clay
Thickening
Pond
Beneflclatlon
Plant
Watte Cla* Slurry
Tallinn*
Dewater
O.B. Dewater
Talllngm/Clay
Mixing
Station
Tailings
Stockpile
Overburden/
Clay Mixing
Station
Overburden
Screening/
Washing
Station
Tailings/Clay
Mix Area
(Mined Out)
Oversize
Material
Overburden/Clay
Mix Area
(Mined Out)
Slurry Water
Overburden
Removal
(Dragline)
Overburden
Transport
(Pumps)
Current
Mining
Area
Matrix Slurry Water
Decant Water
SOURCE: ZELLARS-WILLIAMS
-------
CS-2. The areas mined during this period would provide the area for construc-
tion of two dredge ponds for testing the sand/clay mixture disposal method.
The two conventional settling areas would be filled during year 5 and the
sand/clay mix system would be activated near the end of year 5.
After the sand/clay mix system becomes operational (about year 7), the over-
burden sand/clay mix system would be started. Matrix mining must proceed at a
steady rate to permit disposal of the overburden sand/clay mixture on a con-
tinuous basis. The overburden sand/clay mixture would be disposed of in mined
areas as those areas become available. Disposal areas must be prepared on an
annual basis to accommodate the overburden sand/clay mix. This requires
smaller disposal areas and increases both the perimeter and the height of the
impoundment dikes.
Ten fill areas totaling 3,020 acres would be used as sand tailings fill areas.
With the exception of one area, all the areas would be filled with sand tail-
ings to within two feet of natural grade. The overburden spoil piles would
then be graded over the fill to achieve an overburden cap averaging two feet
in depth. North of Bowlegs Creek is an area scheduled for a low level fill
with approximately five feet of sand tailings. After capping with overburden,
the final surface elevation would be below natural grade but above the water
table.
The overburden/clay waste disposal case would require an average dike height
of 38 feet. The overburden sand/clay mix areas would be filled with a 25
percent mixture which equals 329.5 tons of dry clay per acre-foot of mix. The
wastes disposed of in the mix areas would consolidate more rapidly than
unmixed clay wastes deposited in conventional settling areas, but this fact
would not reduce the height of the dikes required at the time of filling. The
estimated power consumption for pumping waste sand and clay in this waste
disposal case would be 2,444 x 106 kWh over the life of the mine.
2.5.4.2 Environmental Considerations
Environmental Advantages: This case would have the least amount of above-
grade clay settling areas (2,847 acres). The average dike height would be
reduced about one foot compared to the proposed conventional case. The
2-62
-------
active settling acreage and probability for a dike failure are about equal to
that for the sand/clay mix case. Should a dike failure occur, the sand/clay
mix material would not flow as quickly nor as far as the clay material. The
sand/clay mix material would initially consolidate more rapidly than the clay
material.
Environmental Disadvantages: The overburden/clay mix disposal case would
generate the highest levels of fugitive dust, combustion emissions and noise
levels of all cases. The power consumption for pumping waste sand and clay
would be greatest of all the cases (144 percent greater than that required for
the proposed conventional case). This method of disposal would require the
greatest effort to recover phosphate reserves at a future date when advanced
technology becomes available (0.16 ton of phosphate per ton of waste sand and
clay). The overburden/clay mix case involves mining of overburden sand and
sand/clay mix disposal, neither of which has been practiced in conjunction
with phosphate mining. The risks of failure with the overburden/clay mix
case, therefore, are greatest of all the cases.
2.5.5 SUMMARY COMPARISON
Table 2.5-11 presents comparative values for key areas of environmental
evaluation. The conventional waste disposal case, while it is the least
energy consumptive and the most proven technique, carries with it the problems
and disadvantages traditionally associated with above-ground clay disposal,
and an improved method involving the new technology of sand/clay mixing is in
order. However, due to the limited quantity of sand available at the Mobil
site for mixing with waste clay, the sand/clay mix technique could only be
employed over a portion of the site. The sand/clay mix case would have to be
a combination of sand/clay mix and conventional settling, resulting in only
partial mitigation of the disadvantages of conventional settling. The over-
burden/clay mix case was formulated in an effort to supplement the limited
sand resource. However, the energy requirements of the overburden/clay mix
case are so high as to make this alternative infeasible, and the tremendous
energy consumption is not offset by significant environmental gains.
The sand/clay cap plan was conceived as a means to take the fullest advantage
of the limited sand resource and achieve most of the benefits of sand/clay mix
2-63
-------
TABLE 2.5-11
SUMMARY OF WASTE DISPOSAL EVALUATION
Item
Average Dike Height of Above-Grade Basins
(feet)
Area of Above-Grade Settling Basins,
clay and sand/clay mix (acres)
Area of Above-Grade Clay Settling Basins,
capped or uncapped (acres)
Area of Above-Grade Clay Settling Basins,
without cap (acres)
Areas of Sand Tailings and Overburden Fill
(acres)
r\> v '
2 Areas of Below-Grade Settling Basins
*" (acres)
Phosphate Resources in Waste Disposal
Areas, with clay (ratio of phosphate
waste material)
Groundwater Consumption
(mgd)
Dike Failure Risk Rating
(4 = Highest Potential )
Energy Consumption for Pumping
(10* kWh)
Technology Risks (number of processes
or operations not proven)
Conventional
Clay
Settling Case
39
8,170
8,170
6,681
5,511
1,513
to
0.44
16.4
4
1,004
0
Sand/Clay
Cap
Case
37
8,170
8,170
0
5,511
1,513
0.35
16.4
1
1,252
1
Sand/Clay
Mix
Case
35
8,339
4,827
1,642
4,760
2,095
0.24
16.2
3
1,358
Overburden/
Clay Mix
Case
38
8,339
2,847
0
4,760
2,095
0.15
16.4+
2
2,444
SOURCE: STUDY DATA
-------
(while eliminating conventional disadvantages) over the entire site. Briefly,
the sand/clay cap case reduces dike heights, reduces the maximum acreage of
active clay settling areas, and thus reduces the probability of dike failure.
At the same time, it is relatively energy efficient, maintains the unrecovered
phosphate resource in a form amenable to later extraction by improved techno-
logy, and employs largely proven technology so that its chances for successful
application and anticipated results are high. In conclusion, the sand/clay
cap waste disposal case is the environmentally preferred alternative.
2.6 RECLAMATION ALTERNATIVES
Reclamation plans are closely related to the waste disposal method employed in
that the waste disposal plans determine the acreages for each reclaimed area
and the final land use options. Reclamation goals following any type of waste
disposal include returning the land to conditions as similar to premining as
possible and with the least restrictions on future land uses.
2.6.1 CONVENTIONAL CLAY SETTLING PLAN (MOBIL'S PROPOSED ACTION)
2.6.1.1 General Description
During the course of mining, Mobil would disturb and reclaim 15,194 acres of
the South Fort Meade Mine site. Of the 2,055 acres of wetlands on the site,
1,923 acres would be disturbed by mining. When reclamation is complete, the
total wetland acreage would be approximately 93 percent of that existing on
the site; the combined forested stream channel and wetland acreage would ex-
ceed the existing wetland acreage by approximately seven percent. The
reclaimed site is also scheduled to have approximately 1,940 acres planted as
upland hardwood and mixed forest. Reclaimed upland mixed forest would serve
to expand the forested zone along the Peace River and Bowlegs Creek and pro-
vide densely forested stands. The acreage distribution of the various land
use categories for both reclaimed and undisturbed land is shown in Table
2.1-1.
Figure 2.1-E shows the reclaimed areas on the site. Agriculture would be the
predominant use of the reclaimed site, with more than a 49 percent increase in
improved pasture acreage. Planted pine acreage, presently occupying 340
2-65
-------
acres, would be harvested before mining begins. Planted pine reforestation
(453 acres) would cover 34 percent more of the reclaimed site.
Reclamation of Landforms: The following summary shows the acreage totals for
the proposed reclaimed landforms.
Reclaimed Landform Reclaimed Acreage
Sand tailings fill areas with overburden cap 5,034*
Above-grade clay settling areas (uncapped) 6,681
Above-grade clay settling areas with sand cap 1,489
Below-grade clay settling areas 1,513
Overburden fill areas 308*
Miscellaneous backfill areas (clear water pool) 45
Disturbed natural ground
(plant site and entrance railroad) 124
Total 15,194
* Includes setbacks from public roads and property boundaries which would be
disturbed but not mined.
Sand Tailings Fill Areas: The 5,034 acres of sand tailings fill areas would
be capped with overburden to an average depth of two feet in order to provide
a reclaimed soil with favorable agronomic properties. The majority of the
sand tailings fill areas would be initially reclaimed to improved pasture.
Sand tailings fill areas TF-2 and TF-3 (Figure 2.5-B) are scheduled for pine
plantings and would be the first large upland reclamation areas on the site.
Above-Grade Clay Fill Areas: The 6,681 acres of uncapped above-grade clay
fill areas would have phosphatic clay both as the backfill material and the
reclaimed surface soil. Soils such as these are best suited to perennial
forage crops; therefore, improved pasture would.be established on most of the
above-grade clay fill areas. The development of improved pasture would
control erosion and stabilize the reclaimed soils.
Above-Grade Clay Fill Areas Capped with Sand: The 1,489 acres of clay settl-
ing areas capped with sand would have sand tailings as the surface soil and
2-66
-------
clay as the subsurface fill. The thickness of the proposed sand cap would
range from 8 to 10 feet. Some of the sand capped clay settling areas would be
used as improved pasture as has been done in the past. Other areas would be
reforested with a mixture of native tree species.
Below-Grade Clay Settling Areas: These areas are discussed under Reclamation
of Stream Channels and Wetlands.
Overburden Fill Areas: The eight overburden fill areas (308 acres) would have
overburden as both the backfill and surface soil material. These areas would
be reclaimed to approximately natural grade and would have good structural sta-
bility and drainage properties. Since overburden soils have good structural
stability, nutrient retention capacity and moisture holding capacity, the
reclaimed overburden areas would constitute multipurpose land suitable for a
variety of structural and agricultural uses similar to those of the present
site.
Disturbed Natural Ground and Miscellaneous Backfill Areas: The reclaimed
plant site area would include both natural ground and the clear water pool
backfilled with overburden. As such, the area would have sufficient load
bearing strength to permit unrestricted post-reclamation development. The
natural and overburden surface soils would be capable of supporting agri-
cultural uses such as improved pasture and silviculture. The initial plan is
to reclaim this area as improved pasture.
Relamation of Stream Channels and Wetlands: The proposed plan provides for
the reclamation of approximately 60,000 linear feet of stream channels and
1,780 acres of wetlands on the site. The reclaimed stream channels would
replace the minor tributaries of the Peace River and Bowlegs Creek which would
be disturbed by mining. Two types of wetlands included in the reclamation
plan are below-grade clay fill areas and shallow depressions near the conflu-
ence of restored stream channels with natural drainage courses.
Stream Channel Reclamation: Included in the stream reclamation plans are the
disturbed portions of Gilshey Branch, Gurr Run, Stephens Branch, Maron Run,
Propps Branch and several unnamed tributaries to Bowlegs Creek. In addition,
a stream channel would be reclaimed to drain the south central portion of the
site south to Parker Branch.
2-67
-------
All stream channel reclamation would be done in sand tailings fill or over-
burden fill areas. Stream channel reclamation plans provide for the creation
of a normal water level channel and an associated floodplain. A gradall or
small dragline would be used to excavate a channel in a meandering fashion
through the reclamation areas. The floodplain for the reclaimed stream would
be provided by grading the bank slopes to gentle gradients. In the sand tail-
ings fill areas, the excavation and rough grading would be done in the sand
fill prior to the deposition of the overburden cap. Final grading and sloping
of the floodplain would be done during placement of the overburden cap.
In all reclaimed stream channels, shallow pools would be excavated at inter-
vals of approximately 500 feet along the length of the channels. These pools
would be designed to have a bottom depth three feet below the reclaimed stream
bed and would be about 100 feet in diameter. The inclusion of these shallow,
permanent pools along the channels would serve as a water supply for wildlife
and cattle.
Tentative locations and approximate drainage basins for the reclaimed stream
channels planned for the site are shown in Figure 2.6-A. The exact location
of the reclaimed stream channels would depend primarily on the internal drain-
age pattern in each reclaimed area. Although not in exactly the same loca-
tion, the reclaimed channels would be in the same general vicinity as the
existing streams. Where possible, the reclaimed streams would be designed to
have approximately the same lengths and drainage basins as existing streams.
Reclaimed elevations have been planned to provide gradients towards the major
undisturbed drainage courses on the site. When reclamation is complete, the
western and southwestern portions of the site would drain to the Peace River,
the northern and northeastern portions to Bowlegs Creek, and the south central
and southeastern portions to Parker Branch.
Below-Grade Clay Filled Areas: Below-grade clay filled areas (1,513 acres)
would be designed specifically for wetland reclamation. All reclaimed wet-
lands would be positioned on the site to receive drainage from upland recla-
mation areas. Drainage outfalls and fill levels would be designed to provide
areas of open water adjoined by seasonally flooded zones gradually sloping up
to the graded spoil areas which would be inundated only at high water. When
2-68
-------
PROPOSED LOCATIONS AND APPROXIMATE DRAINAGE BASINS
FOR RECLAIMED STREAM CHANNELS
CONVENTIONAL PLAN
Reclaimed Stream
Channels
T)GHshey Branch
Gurr Run
(5) Stephens Branch
5) Maron Run
§) Propps Branch
S\ Tributary of
fi/ Parker Branch
/TFffi
n ťT
OF-8
OF-1
Out Parcels
(Not Owned By Mobil)
Undisturbed Areas
a Clay Settling With
Sand Tailing Cap
CS Clay Settling
OF Overburden Fill
TF Sand Tailing Fill
With Overburden Cap
- Drainage Boundary
SOURCE: MOBIL
-------
reclamation is complete, Area CS-14 would receive a portion of the drainage
from CS-13 (Figure 2.5-B). Area CS-15 would receive drainage from CS-1, CS-7,
CS-12, TF-8 and TF-21. The below-grade nature of these areas, the clay base,
and the drainage inputs from the other reclamation areas should be sufficient
to maintain a wetland environment.
Shallow Depressions: Thirteen shallow depressions would be constructed on 345
acres of marsh where drainage exits reclaimed waste disposal areas. These
depressions are desirable for use as reclaimed wetlands. The dikes would be
graded away from the areas to leave the depressions intact. The size of the
ponded area would be controlled by the design elevation of the overflow drain-
age swale. The elevation of the overflow swale would be designed so that at
high water, the ponded area would cover an area equivalent to three percent of
the acreage represented in the drainage basin for the reclaimed wetland. In
the immediate vicinity of the overflow swale, a gradall or small dragline
would be used to deepen the depression to a minimum depth of four feet below
the elevation of the swale. This excavation is intended to provide a perma-
nent standing water component in the reclaimed wetland. The reclaimed wetland
would consist of a small area of permanent water around the overflow drainage
swale surrounded by a larger, gently sloping area that is seasonally flooded
(Figure 2.6-B).
Revegetation: The conventional clay settling reclamation plan would provide
for revegetation of all land disturbed by mining. The six basic revegetation
programs in this plan are reforestation along reclaimed stream channels, wet-
land reforestation, nonforested wetland revegetation, upland mixed refore-
station, commercial pine plantings, and improved pasture planting. Each of
these programs is discussed in detail in the following subsections.
Reforestation Along Reclaimed Stream Channels: Reforestation of 277 acres
would be accomplished along the reclaimed stream channels. Because of the
limited experience with reforesting stream channels, Mobil initiated a refore-
station feasibility study on Sink Branch near Fort Meade in the fall of 1979.
A portion of Sink Branch had been disturbed by a phosphate mining operation in
the 1950's. In the feasibility study, Mobil excavated a meandering channel
(through an adjacent reclaimed area) for rerouting a section of the creek.
2-70
-------
FIGURE 2.6-B
FORMATION OF SHALLOW DEPRESSIONS
Ponded water
Fill W$$$&
During fill
;v;V Dam ;';-^:'.':';':-->A-':ij:i.:;
Low water
High water
During reclamation
SOURCE: ZELLAR8-WILLIAMS
2-71
^/-Overflow
X. swale
NOTE NOT TO SCALE
-------
The new channel was then divided into four segments for the following soil
treatment:
o 1-foot layer of organic soil over overburden substrate
o 0.5-foot layer of organic soil over overburden substrate
o Overburden substrate plus fertilization as dictated by soil test
o Overburden substrate alone, i.e., the control segment.
The three types of transplant stock used in the plantings were two-inch to
four-inch native trees obtained from nearby Mobil property, potted native seed-
lings obtained from a commercial nursery, and bare-root native seedlings
obtained from the Division of Forestry.
The reclamation area is being monitored by Mobil to assess the impact of diver-
sion on water quality and the effect of soil treatment and transplant type on
tree survival. Mobil plans to continue monitoring the Sink Branch reclamation
area as well as the ongoing Division of Forestry research program on the
reforestation of disturbed phosphate land. The results of these and other
projects are expected to point the way to improved reforestation techniques
for reclaimed phosphate land.
Mobil proposes to reforest the reclaimed stream channels in a manner similar
to that followed at Sink Branch. Figure 2.6-C depicts the proposed plantings
along the stream channels. Hydric species such as cypress and black gum would
be planted along the margins of the reclaimed channel. Transition species
such as sweetgum, red maple, and laurel oak would be planted in the reclaimed
floodplain of the streams. Mesic species such as slash pine and dogwood would
be planted along the margins of the forested areas.
Potted seedlings would be used as the primary transplant stock in the refore-
station effort. This stock has exhibited good survival rates and offers the
greatest flexibility in terms of planting dates and availability. Potted
transplant stock would be supplemented with tree-spade and bare-root trans-
plants when appropriate species are available in on-site areas that are to be
mined. Approximately 10 foot by 10 foot spacings are planned for the refore-
station areas. This results in a planting density of more than 400 trees per
acre. If the survival rate falls below 50 percent after one growing season,
2-72
-------
REFORESTATION OF RECLAIMED STREAM CHANNELS
V- **-.sK*
m^-
\' -'-
BB8RWŤf*V ''-
Stash Pine
Dogwood
Black Gum Black Gum
Swaatgum SwŤetgum
Red Maple Red Maple
Laura) Oak Cyprass LauralOak
Slash Pina
Dogwood
>ť.-':!^-'/iVŤ-v:. .ť*:**!
SOURCE: MOBIL
NOTE NOT TO SCALE
ro
-
o
-------
additional plantings would bring the density to a minimum of 200 trees per
acre.
Wetland Reforestation: The proposed wetland revegetation program for below-
grade clay fill Area CS-14 is graphically represented in Figure 2.6-D. The
478 acres of graded spoil areas would be reforested with a variety of native
tree species. Wetland species such as bald cypress, blackgum, and water ash
would be the dominant plantings. A planting density of approximately 400
trees per acre is planned with both bare-root and potted seedlings as trans-
plant stock. If necessary, the areas would be replanted to achieve a minimum
stand density of 200 trees per acre.
Nonforested Wetland Revegetation: Approximately 957 acres of marsh would be
reclaimed in the below-grade clay fill area CS-14. An additional 354 acres of
marsh would be provided by the shallow depressions created in above-grade clay
fill areas. All reclaimed marshes would be adequately revegetated to enable
them to perform their intended wetland functions.
As with wetland reforestation, the revegetation of reclaimed marshes is cur-
rently receiving heavy research emphasis by the phosphate industry. Ap-
proaches to marsh revegetation include the use of substrates from existing
marshes as a seed and vegetative propagule source, the transplanting of the
desired vegetation from existing marshes, and simply allowing wetland environ-
ments to revegetate naturally. Each approach has been successful in certain
areas. Research may suggest more effective alternative approaches. In view
of the rapid developments in this field, Mobil maintains that specifying de-
tailed marsh revegetation plans for reclamation efforts that would take place
more than ten years in the future is inappropriate. Mobil is required by
state law to provide a 50 percent herbaceous cover on all nonforested wet-
lands. Mobil proposes that they submit specific marsh revegetation methods
at the time that the reclamation plans for these areas are submitted to the
state for approval. These specific methods would be based upon the best state-
of-the-art technology then available.
Upland Mixed Reforestation: The reclamation plan would provide for refore-
station of approximately 1,271 acres of upland with a mixture of native tree
2-74
-------
REVEGETATION OF BELOW-GRADE CLAY RECLAMATION AREA
Sweetgum
Red MapU
\ff Laurel Oak
Sweet Gum
Red Maple
Laurel Oak
<:;V-:^'::GRAPED SPOIL
v^L^^r;;: u-.-V-;-'?>::?'--v. ,.--:;°-,;::.-,
i|J|iRft%;^^^
^P&^vSSv!^ ft^?S^=
SUBSIDED BACKFILL
?&$$%LEVEL ;:
t*,v.>r-.;;...-:;^;-,-;. .>:;.;-ť.-.o--.*..-.'-;. .'V.. ..'./': -^siip-
.'- .-.-; .. : ... ...-.;. ...Ť.<;.. .? .-. -.o ^SiS
' "' ° " '' *
SOURCE: MOBIL
NOTE NOT TO SCALE
-------
species. Two general types of plantings would be included in the upland
reforestation areas. One consists of reforestation plantings adjacent to un-
disturbed forested areas. The reclamation plan would provide for the refore-
station of approximately 500-foot wide strips on reclaimed land adjacent to
the undisturbed forested areas along the Peace River and Bowlegs Creek. The
plan also provides for a 41-acre reforestation block adjacent to the forested
area along the undisturbed lower portions of Maron Run.
The second type of upland mixed reforestation would be the planting of elon-
gated strands approximately 200 feet wide in reclamation areas. These strands
would provide reclaimed areas with densely forested strips to serve as cover
and feeding grounds for wildlife, corridors for wildlife movement, aesthetic
breaks in the landscape, and eventual shade areas for cattle. Whenever re-
claimed soil conditions permit, the strands would be planted in a configura-
tion that dissects reclamation areas. Because of the questionable structural
ability of clay soils to support mature tree growth, reforestation strands in
reclaimed clay fill areas would be planted along the graded remnants of the
waste disposal dikes. Figure 2.1-E depicts the conceptual scheme for the
upland mixed reforestation plantings.
A variety of native hardwood and coniferous trees would be included in the
reforestation plantings. Species such as longleaf pine, live oak, and dog-
wood would be planted on the well-drained sites, while species such as water
oak, laurel oak, sweetgum, and slash pine would be planted on the wetter
sites. All these species are available either as potted seedlings from
commercial nurseries or bare-root seedlings from the Division of Forestry.
Mobil currently plans to use potted seedlings as the primary transplant stock
for the hardwood species and bare-root seedlings as the transplant stock for
pine species. When appropriate species are available nearby, tree-spade trans-
plants would supplement the seedling transplant stock.
An average planting density of approximately 400 trees per acre is planned for
the upland reforestation areas. This corresponds to an average spacing of
about 10 feet by 10 feet, but not all reforestation plantings would be made at
this regular spacing. At various intervals throughout the upland reforesta-
tion plantings, dense thickets would be planted to provide escape cover for
2-76
-------
wildlife and general diversity to the planting scheme. These thickets would
average about an acre in size and would be planted generally in a single
species at a density of about 1,000 trees per acre. All reforestation areas
would be replanted as necessary to achieve an average density of 200 trees per
acre after one growing season. The reforestation areas would be protected
from grazing for a period of five years. During this period, additional
natural reforestation of these areas would probably occur. Black cherry and
sugarberry, whose seeds are dispersed by birds, are likely volunteer species
in the strands and blocks that do not adjoin undisturbed forests. In the
reforestation zones adjacent to the undisturbed forested areas, a more diverse
volunteer tree growth is expected because of the proximity of the natural seed
source.
Pine Plantings: Approximately 453 acres of planted pine reforestation would
replace the 339 acres of existing pine plantations that would be mined. Pine
plantings would be included in Areas TF-2 and TF-3. These areas are among the
first large upland reclamation areas available on site. The pine plantations
would be established using standard commercial reforestation techniques.
During the winter dormant season, bare-root slash pine seedlings would be
transplanted at a spacing of 8 feet by 8 feet for an initial planting density
of approximately 680 trees per acre. If the pine plantings are successful in
Areas TF-2 and TF-3, Mobil may amend its proposed revegetation plan to include
more pine plantings in the latter stages of mine life.
Improved Pasture Planting: The reclamation plan would provide for improved
pasture as the initial vegetative cover for approximately 11,413 acres of
reclaimed land. Improved pasture would be established on portions of all
upland reclaimed landforms (clay settling areas and sand tailings fill areas
with overburden cap) and would be the dominant vegetative cover on the
reclaimed site.
All improved pasture plantings would include both a grass and a legume compo-
nent. Legumes, in combination with their bacterial symbiont, have the capa-
city to fix atmospheric nitrogen for utilization by higher plants. Therefore,
the legume component would serve both as a forage complement to the grass and
as a source of nitrogen to the sod. An effort would be made to select the
'2-77
-------
best forage species for the particular landform and reclaimed surface soil
type. Mobil proposes to select the particular grass and legume species to be
used in revegetation at the time Mobil's reclamation programs for the parti-
cular areas are filed with the state. However, unless more promising species
become available, Pensacola bahiagrass would be the principal grass used in
the revegetation program. Legumes would be either interseeded with the grass
or overseeded on established grass sods. All legume seed would be inoculated
with the proper bacterial inoculant to ensure the capacity to fix atmospheric
nitrogen. Prior to all forage plantings, fertilizer and lime would be applied
according to soil test results. The need for lime is unlikely on most
reclaimed soils in view of the high pH and calcium and magnesium levels
reported for the reclaimed soil materials. All improved pasture areas would
be protected from grazing until the forage plantings are firmly established.
Annual Reclamation Schedule: Table 2.6-1 summarizes the proposed annual recla-
mation schedule for the South Fort Meade Mine. In preparing this schedule, a
total of three years after final fill is allotted to complete reclamation of
sand tailings and overburden fills. Of this total, two years would be
utilized in grading the areas to approved slopes, establishing drainage and
planting vegetative cover. The third year is allotted for the vegetative
cover to become established.
After final fill, seven years have been allotted to complete reclamation of
uncapped clay settling areas. Of this total, three years are projected to be
required for the areas to consolidate to 20 percent solids; three years to
grade, establish drainage and plant a vegetative cove"; and one additional
year to allow the vegetative cover to become established.
Two years have been allotted after placement of the sand cap to complete recla-
mation of capped clay settling areas. One year is required to grade the fill
and retaining dikes to approved slopes and to plant the vegetative cover; the
remaining year is required for the vegetative cover to become established.
Because the mined areas would be used for waste disposal, reclamation lags sev-
eral years behind the mining schedule. Reclamation activities initially pro-
ceed at a slower rate than mining activities; however, reclamation proceeds
rapidly for the last one-third of mine life and out-paces the rate of distur-
bance.
2-78
-------
TABLE 2.6-1
ANNUAL RECLAMATION SCHEDULE
(Conventional Plan)
Year
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Areas Reclaimed
OF-1
OF -2
TF-1
TF-2. CS-1, TF-3
OF -3
TF-4, CS-2
TF-5
OF-4, TF-6
TF-8
TF-7, CS-3
TF-9
OF-5, TF-10
TF-11
TF-12, OF-6, TF-13, TF-14
TF-15
OF-7, TF-16, TF-17
OF -8, TF-18, TF-19, TF-20
TF-21, CS-4, CS-5, CS-8, CS-9
TF-22
CS-6, CS-10
CS-7
CS-11
CS-12
TF-23, Plant Site, RR, and CWP
CS-1 3
CS-14
CS-15
Acreage Reclaimed
During Year
25
32
20
1,064
32
671
135
293
40
1,155
286
390
135
389
365
1,007
704
1,825
230
1,770
735
690
520
578
590
520
993
Reclaimed
Acreage
Cumulative
Total
25
57
77
1,141
1,173
1,844
1,979
2,272
2,312
3,467
3,753
4,143
4,278
4,667
5,032
6,039
6,743
8,568
8,798
10,568
11,303
11,993
12,513
13,091
13,681
14,201
15,194
SOURCE: MOBIL
2-79
-------
2.6.1.2 Environmental Considerations
Environmental Advantages: The conventional method of reclamation has been
thoroughly utilized and tested by the industry over the years so that this
plan is operationally the most proven.
Environmental Disadvantages: With the conventional plan, post-reclamation
elevations and topography would be most altered from those existing since
reclaimed landforms would extend the highest (45 feet) of the four relevant
cases above the existing grade. The conventional reclamation case would in-
volve the greatest alteration to existing surface water drainage patterns
since the Parker Branch basin would be increased by 691 acres. The amount of
reclaimed wetland acreage would be the least of the four cases, as would the
amount of reclaimed upland mixed forest acreage. The conventional plan would
have the largest area (6,681 acres) of above-grade clay settling without any
cap and thus with waste clays as the surface soil. The exposed clay settling
areas would have the highest post reclamation levels of soil radioactivity (22
pCi/g of radium-226) of all reclaimed landforms. Clay settling areas require
a five to seven year period of crusting and the crust that forms is hard and
difficult to till and tends to become water-logged. These areas would also
have poor structural stability in both the short term and the long term. The
clay disposal areas would block and divert groundwater in the regional
Surficial Aquifer which would result in an altered flow of water through the
Surflcial Aquifer compared to premlnlng conditions. Recharge to the artesian
aquifer from the mine site would be reduced the greatest of all the plans.
2.6.2 SAND/CLAY CAP PLAN
2.6.2.1 General Description
The sand/clay cap plan, like the conventional plan would also involve the dis-
turbance and reclamation of 15,194 acres of the South Fort Meade Mine site.
Of the 2,055 acres of wetlands on the site, 1,923 acres would be disturbed by
mining. When reclamation is complete the total wetland acreage (1,925 acres)
would be approximately 93 percent of the existing acreage. The combined
forested stream channel and wetland acreage would exceed the existing acreage
in those categories by 14 percent.
2-80
-------
The reclaimed site is scheduled to have approximately 1,451 acres of upland
mixed forest, which would serve to expand the forested zone along the Peace
River and Bowlegs Creek and provide densely forested strands. The acreage
distribution of the various land use categories for both reclaimed and un-
disturbed land is shown in Table 2.6-2. Figure 2.6-E shows the post-
reclamation land uses for the sand/clay cap plan.
Agriculture would be the predominant post-reclamation land use, with a 43
percent increase in improved pasture acreage. There would be a 57 percent
increase in planted pine acreage (from 340 acres to 536 acres).
Reclamation of Landforms: The following summary shows the acreage totals for
the proposed reclaimed land forms.
Reclaimed Land form Reclaimed Acreage
Sand tailings fill areas with overburden cap 5,079*
Above-grade clay settling areas with
sand/clay mix (4:1) cap 7,580
Above-grade clay settling area with over-
burden cap 590
Below-grade clay settling area with partial
overburden cap 1,513
Overburden fill areas 308
Disturbed natural ground
(plant site and entrance railroad) 124
Total 15,194
* Total acreage includes setbacks from public roads and property boundaries
which will be disturbed but not mined.
Sand Tailings Fill Areas: These areas (5,079 acres) would be filled with sand
tailings and then capped with overburden to an average depth of two feet to
bring the reclaimed surface to approximately natural grade. Although most
would be reclaimed to pasture, area TF-2, one of the first large upland re-
clamation areas on the site, would be used for pine plantings.
2-81
-------
TABLE 2.6-2
LAND USE CATEGORIES
(Sand/Clay Cap Plan)
Improved Pasture
Cutover Flatwoods
Upland Hardwood Forest
Upland Mixed Forest
Planted Pine
Water Areas
Forested Stream Channels
Freshwater Swamp
Freshwater Marsh
TOTAL
Reclaimed
Acreage
11,003
0
0
1,451
536
0
279
504
1,421
15,194
Undisturbed
Acreage
108
182
664
5
0
3
0
111
21
1,094
Total
11,111
182
664
1,456
536
3
279
615
1.442
16,288
SOURCE: ZELLARS-WILLIAMS
2-82
-------
POST RECLAMATION LAND USE - SAND/CLAY CAP
PLANTED MIXED
FOREST ALONG
STREAM CHANNELS
PLANTED UPLAND
MIXED FOREST
PLANTED PINE
WETLANDS
UNDISTURBED AREAS
PASTURE
OUT PARCELS
(NOT OWNED BY MOM]
SOURCE: ZELLARS-WILLIAMS
-------
Above-Grade Clay Settling Areas Capped with Sand/Clay Mix: Above-grade clay
settling areas capped with sand/clay mix as the surface soil represent the
largest area (7,580 acres) of any reclaimed landform proposed for the site.
The cap would range from four to six feet thick and would be composed of a 4:1
ratio of sand to clay. These areas would be reclaimed as improved pasture.
Above-Grade Clay Settling Area Capped with Overburden: Area CS-13 (590 acres)
would have phosphatic clay as the subsurface fill and overburden as the re-
claimed surface soil. The land use potential of this area would be similar,
but not identical, to clay settling areas capped with sand/clay mix. The area
would be reclaimed as improved pasture. These areas would be reclaimed as
improved pasture.
Below-Grade Clay Settling Areas with Partial Overburden Cap: See discussion
under Reclamation of Stream Channels and Wetlands.
Overburden Fill Areas: The eight overburden fill areas (308 acres) would have
overburden as both the backfill and surface soil material. The areas would be
reclaimed to approximately natural grade and would have good structural
stability and drainage properties. Reclaimed overburden areas would consti-
tute multipurpose land suitable for a variety of structural and agricultural
uses.
Disturbed Natural Ground: The reclaimed plant site area would include both
natural ground and the clear water pool backfilled with overburden. As such,
the area would have sufficient load bearing strength to permit unrestricted
post-reclamation development. The natural soils would be capable of sup-
porting agricultural uses such as improved pasture and silviculture. The
initial plan is to reclaim this area as improved pasture.
Reclamation of Stream Channels and Wetlands: The two major drainage courses
on site, the Peace River and Bowlegs Creek, would not be disturbed by the min-
ing operation, and as with the proposed action, the drainage pattern to these
streams would be restored by reclaiming forested stream channels to serve as
tributaries. The plan also provides for wetland reclamation in shallow depres-
sions in above-grade reclamation areas and below-grade clay fill areas.
2-84
-------
Stream Channels: The 60,000 linear feet of reclaimed stream channels would
replace disturbed portions of Gilshey Branch, Gurr Run, Stephens Branch, Maron
Run, Propps Branch and several unnamed tributaries to Bowlegs Creek (Figure
2.6-F). In addition, a stream channel would be reclaimed to drain the south
central portion of the site south to Parker Branch. The exact location of the
stream channels would depend primarily on the internal drainage pattern in
each reclaimed area. Although not in exactly the same location, the reclaimed
streams would be in the same general vicinity as the existing streams and
would tie in with undisturbed downstream portions. Where possible, the
reclaimed streams would be designed to have approximately the same lengths and
drainage basins as the existing streams.
With the exception of the reclaimed channel for Propps Branch, stream channel
reclamation would be done in sand tailings fill or overburden fill areas. In
the sand tailings fill areas, the excavation and rough grading would be done
in the sand fill prior to the deposition of the overburden cap. Final grading
and sloping of the floodplain in these areas would be done during the place-
ment of the overburden cap. In the reclamation of Propps Branch (Area CS-10)
the excavation and grading would be done during the final reclamation of the
area when the surface sand/clay mix has consolidated to 30 percent clay
solids.
Shallow Depressions in Above-Grade Areas: The above-grade shallow depressions
(in CS-1 through CS 13) would be created at drainage outlets to serve pri-
marily as wetlands collecting water draining from the areas. In CS-1 through
CS-12, the depressions would be created during placement of the sand/clay mix
cap. The thickness of the sand/clay mix cap would determine the depth of the
depressions. Consequently, depression depths would range from four to six
feet in the 12 areas that are to be capped with sand/clay mix. The water
level in the depressions would be established by the outfall elevation of the
overflow drainage swale as shown in Figure 2.6-B.
In CS-13, the above-grade settling area that is to be capped with overburden
rather than sand/clay mix, the wetland depression would be created by con-
trolled grading of the dike during reclamation. The site of the depression
2-85
-------
PROPOSED LOCATIONS AND APPROXIMATE DRAINAGE BASINS
FOR RECLAIMED STREAM CHANNELS
(SAND/CLAY CAP PLAN)
Reclaimed Stream
Channels
ŠGllthey Branch
(2)Gurr Run
(3)StŤphŤnŤ Branch
@Maron Run
@Proppa Branch
ŠTributary of
Parker Branch
LEGEND
t Parcel*
L...J(Mot OwnadBy Mobil
turbed Areas
DVB Overburden
SC Sand-Clay
C8 Clay Settling
OF Overburden Fill
TF Sand Tailing Fill
With Overburden Cap
* Drainage Divide
OF-Ť
OF-1
SOURCE: ZELLARS-WILUAMS
-------
would be selected to coincide with an outlet spillway location, where an accu-
mulation of fine particles generally results in greater subsidence and the
formation of shallow, gently sloping depressions. During reclamations of
CS-13, the dikes would be graded away from the selected wetland area to leave
the depression intact. The size of the ponded water area would be determined
by the design elevation of the overflow drainage swale. As with the other
wetland depressions, the ponded area should cover approximately five percent
of the total area of CS-13 at high water level.
Below-Grade Clay Fill Area with Partial Overburden Cap: The filling level of
Area CS-14 has been planned to permit reclamation of the entire area (1,513
acres) as a wetland. The original clay fill level in the area would average
approximately three feet below existing grade. Following clay deposition, sur-
face water should be drawn off to promote subsidence and consolidation of the
clay fill in the interspoil depressions. The protruding spoil piles would
then be graded into the depressions so that the entire area would be below
grade at reclamation. The grading would also result in the partial capping of
the consolidated clay fill.
In addition to its below-grade elevation, the area would be located down gra-
dient from other reclamation areas which would serve as a drainage basin for
the wetland. When reclamation is complete, Area CS-14 would receive all the
surface drainage from Areas CS-1, CS-12 and TF-8, as well as a portion of the
drainage from Areas CS-13, TF-23 and the outparcels adjacent to the northwest
oortion of the area.
In order to maintain a wetland environment over the entire area, it would be
necessary to establish a series of water levels within the area and to step
down these levels by a series of overflow drainage swales. According to this
plan, the area would be divided into four segments, with water levels held at
135 foot, 130 foot, 125 foot and 120 foot mean sea level (MSL) elevations by
controlled grading of overburden spoils. The water levels would be set along
the approximate original contour lines for the particular elevation so that
the reclaimed water levels would be at or below the premining grade elevations
for the area. The subdivisions would be connected by means of overflow
drainage swales.
2-87
-------
Revegetation: The revegetation strategy for the sand/clay cap reclamation
plan would comprise the same six revegetation programs as the conventional
plan: reforestation along reclaimed stream channels, wetland reforestation,
nonforested wetland revegetation, upland mixed reforestation, commercial pine
planting and improved pasture plantings. The post-reclamation land uses with
the sand/clay cap plan are shown in Figure 2.6-E. The differences between the
sand/clay cap revegetation program and that proposed in the conventional plan
are the areal extent of each of the six types of revegetation programs, and
differences in some of the plant species used in these programs due to the
differences in soil characteristics.
Reforestation Along Reclaimed Stream Channels: Approximately 279 acres of
reforestation would be developed along the reclaimed stream channels. These
stream channels would be reforested in a manner similar to that followed at
Sink Branch (see Section 2.6.1.1). Revegetation would be completed prior to
opening the channels to avoid erosion and turbidity problems. As discussed in
the conventional plan, hydric species such as cypress and black gum would be
planted along the margins of the reclaimed channels. Transition species such
as sweetgum, red maple, and laurel oak would be planted in the reclaimed flood-
plain of the streams. Mesic species such as slash pine and dogwood would be
planted along the margins of the forested areas.
Wetland Reforestation: The reforestation of wetlands would be performed on
504 acres of graded spoils which occur in the below-grade fill areas of CS-14.
These areas would be reforested with a variety of native tree species composed
primarily of bald cypress, blackgum and water ash. The planting would be con-
ducted in the same manner discussed in the proposed action.
Nonforested Wetlands Revegetation: Approximately 1,009 acres of freshwater
marsh would be reclaimed in the below-grade clay fill areas (CS-14). An
additional 412 acres of marsh would be provided by the shallow depressions
created in above-grade clay fill areas. All reclaimed marshes would be ade-
quately revegetated to enable them to perform their intended wetland func-
tions. The revegetation program for these wetlands would be conducted in the
same manner as the proposed action discussed in Section 2.6.1.1.
2-88
-------
Upland Mixed Reforestation: The reclamation plan would provide for refore-
station of approximately 1,451 acres of upland with a mixture of native
species. The upland reforestation plan would consist of two types of plant-
ings. The first consists of reforestation plantings adjacent to undisturbed
forested areas. The reclamation plan provides for the reforestation of approx-
imately 500-foot wide strips on reclaimed land adjacent to the undisturbed
forested areas along the Peace River and Bowlegs Creek. The plan also pro-
vides for a 41-acre reforestation block adjacent to the forested area along
the undisturbed lower portions of Maron Run. The second type of upland mixed
reforestation is the planting of elongated strands approximately 200 feet wide
in the reclamation areas. These areas would serve the same functions
described in the proposed action and the planting would be conducted in the
same manner discussed under the proposed action. In addition, at the junction
of various strands, the planting zone would be expanded to form reforestation
blocks. Figure 2.6-E depicts the conceptual scheme for the upland mixed
reforestation under the sand/clay cap plan.
Pine Plantings: Approximately 536 acres of pine plantings would replace the
339 acres of existing pine plantations to be mined. Pine plantings are sche-
duled for areas TF-2 and CS-4, the first large upland reclamation areas avail-
able on site. Pine plantings on overburden soils such as that of area TF-2
have produced good results; however, there is no previous experience with pine
plantings on sand/clay soils. The silvicultural potential of these soils
would be evaluated by comparing area CS-4 with the planting in area TF-2. The
establishment of the pine plantings would be the same as described in the pro-
posed action (see Section 2.6.1.1). If the pine plantings prove to be success-
ful on the sand/clay soils, the revegetation plan may later be amended by
Mobil to include more pine plantings in the latter stages of mine life.
Improved Pasture Plantings: The reclamation plan would provide for improved
pasture as the initial vegetative cover for approximately 11,003 acres of re-
claimed land. Improved pasture would be established on portions of all upland
reclaimed landforms and would be the dominant vegetative cover on the
reclaimed site.
2-89
-------
Improved pasture would be established in the same manner described in the
proposed action except that the selection of particular grass and legume
species would include additional alternatives which are found to grow favor-
ably in some of the sand/clay soils. In addition to the Pensacola bahiagrass,
discussed in the proposed action, Coastal and Callie bermudagrass varieties
which do well on well-drained reclaimed soils may also be used. These grasses
produce high yields of excellent quality forage under optimum conditions, but
are more selective in their soil requirements and require a higher level of
management. The bermudagrass varieties may be utilized as the grass component
on sand/clay and overburden soil which have good surface drainage.
Annual Reclamation Schedule: Table 2.6-3 displays the proposed annual re-
clamation schedule for the sand/clay cap waste disposal method. In preparing
this schedule, a total of three years after final fill has been allotted to
complete reclamation of sand tailings and overburden landfills. Of this to-
tal, two years would be utilized in grading the areas to approved slopes,
establishing drainage, and planting a vegetative cover. The third year is
allotted for the vegetative cover to become established.
A total of five years after final fill has been allotted to complete the re-
clamation of clay settling areas capped with sand/clay mix. Two years would
be allowed for the material to consolidate to approximately 30 percent clay
solids. The next two years would be used to grade the areas to approved
slopes, establish drainage, and plant the vegetative cover. The final year is
required to allow the vegetative cover to become established.
After final fill, seven years have been allotted to complete reclamation of
the clay settling areas that are to be capped with overburden. Of this total,
three years are projected to be required for the areas to consolidate to 22
percent clay solids; three years to grade, establish the drainage pattern, and
plant the vegetative cover; and one additional year to allow the vegetative
cover to become established. Because the mined areas would be used for waste
disposal and the planned stage fill of the clay settling areas with a sand/
clay mix cap, reclamation lags several years behind the mining schedule. By
the time the early waste disposal areas are deactivated, reclamation proceeds
2-90
-------
TABLE 2.6-3
ANNUAL RECLAMATION SCHEDULE
(Sand/Clay Cap Plan)
Year
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Areas Reclaimed
OF-1
OF-2
TF-1
TF-2, TF-3
OF-3, TF-4
TF-5
OF-4, TF-6, CS-1, TF-8
TF-7, CS-2
TF-9
TF-10
OF-5, TF-11, CS-4
TF-12, TF-13, TF-14
OF-6, TF-15, CS-5
TF-16
OF-7, TF-17, TF-18, TF-19
OF-8, TF-20, TF-21, CS-6
TF-22, CS-7
CS-8
CS-9
TF-23, TF-24, CS-10
Plant Site, RR
CS-11
CS-12
CS-3
CS-13.CS-14
Acreage Reclaimed
During Year
25
32
20
284
163
135
1,113
855
286
300
610
332
722
760
474
1,347
965
620
400
1,598
690
520
840
2,103
Red! aimed
Acreage
Cumulative
Total
25
57
77
361
524
659
1,772
2,627
2,913
3,213
3,823
4,155
4,877
5,637
6,111
7,458
8,423
9,043
9,443
11,041
11,731
12,251
13,091
15,194
SOURCE: ZELLARS-WILLIAMS
2-91
-------
rapidly and out-paces the rate of disturbance for the last part of the mine
life.
2.6.2.2 Environmental Considerations
Environmental Advantages: Placement of a sand/clay or overburden cap over all
uncovered clay settling areas would provide the greatest agronomic potential
of all the alternatives. The stuctural stability (short and long-term) would
be the best of all the alternatives. The average soil radium levels would be
the least of all the alternatives (equal to overburden/clay mix). The radon-
226 concentration of the surface soil would be half the level associated with
the uncapped clay settling areas. The sand/clay cap reclamation plan would
alter drainage areas slightly less than the conventional clay settling plan
since 571 additional acres would drain to Parker Branch as compared to 691
acres.
Environmental Disadvantages: Sand/clay cap reclamation techniques at the pre-
sent time have not been fully tried and proven. The potential reduction in
recharge is essentially the same as the conventional clay settling plan.
2.6.3 SAND/CLAY MIX PLAN
2.6.3.1 General Description
The sand/clay mix plan would involve the disturbance and reclamation of 15,194
acres of the South Fort Meade Mine site. The sand/clay mix reclamation plan
would provide 2,255 acres of wetlands, an increase of 9.7 percent over the
existing site. The combined forested stream and wetland acreage would exceed
the existing wetland acreage in those categories by 34 percent. The reclaimed
site is scheduled to have approximately 1,831 acres of upland mixed forest.
The acreage distribution of the various land use categories for both reclaimed
and undisturbed land is shown in Table 2.6-4. The drainage pattern to the
Peace River and Bowlegs Creek would be restored by reclaiming approximately
60,000 linear feet of stream channel to serve as tributaries. Agriculture
would be the predominant post-reclamation land use, with a 52 percent increase
in improved pasture acreage. There would be a 27 percent increase in planted
pine acreage (from 339 acres to 431 acres).
2-92
-------
TABLE 2.6-4
LAND USE CATEGORIES
(Sand/Clay Mix Plan)
Improved Pasture
Cutover Flatwoods
Upland Hardwood Forest
Upland Mixed Forest
Planted Pine
Water Areas
Forested Stream Channel s
Freshwater Swamp
Freshwater Marsh
TOTAL
Reclaimed
Acreage
10,313
0
0
1,826
431
0
263
746
1,615
15,194
Undisturbed
Acreage
108
182
664
5
0
3
0
111
21
1,094
Total
10,421
182
664
1,831
431
3
263
857
1,636
16,288
SOURCE: ZELLARS-WILLIAMS
2-93
-------
Reclamation of Landforms
The following summary shows the acreage totals for the proposed reclaimed land-
forms. Figure 2.6-G shows the post-reclamation land uses for the sand/clay
mix plan.
Reclaimed Landform Reclaimed Acrage
Sand tailings fill areas 3,020*
Above-grade sand/clay mix areas 3,352
Below-grade sand/clay mix areas 160
Above-grade clay filled areas
capped with sand/clay mix 3,185
Above-grade clay filled areas 1,642
Below-grade clay filled areas 2,095
Overburden fill areas 733*
Graded spoil areas 838
Miscellaneous backfill
(clear water pond) 45
Disturbed natural ground
(plant site and entrance railroad) 124
Total 15,194
*Total acreage includes setbacks from public roads and property
boundaries which will be disturbed but not mined.
Sand Tailings Fill Areas: These areas (3,020 acres) would be filled to near
natural grade with sand tailings and then capped with overburden to an average
depth of two feet, bringing the reclaimed surface to approximately natural
grade. Area TF-9 would have a low level tailings fill followed by an over-
burden cap. The majority of the tailings fill areas would be reclaimed as
pasture.
Above-Grade Sand/Clay Mix Areas and Above-Grade Clay Fill Areas Capped with
Sand/Clay Mix: Above-grade areas with sand/clay mix in the surface soil repre-
sent the largest acreage (6,537 acres) of any reclaimed landform proposed for
the site. Of the 18 areas in this category, six would have clay alone as the
2-94
-------
POST RECLAMATION LAND USE - SAND/CLAY MIX
ro
10
en
LEGEND
FORESTED WETLANDS
LJ WETLANDS
PLANTED MIXED
FOREST
OUT PARCELS
(NOT OWNED BY MOBt.)
FORESTED STREAM
CHANNEL
SOURCE: ZELLARS-WILLIAMS
-------
subsurface fill material with the cap ranging from four to six feet thick. The
remaining 12 areas would have sand/clay mix as both the backfill material and
the surface soil. Sand/clay soils should be suited for agricultural uses such
as improved pasture. Forage crops would cover the majority of these sand/clay
soils. In sand/clay mix areas, both the sand/clay substrate and dike remnants
would be utilized in reforestation.
Below-Grade Sand/Clay Mix Areas and Below-Grade Clay Filled Areas: See dis-
cussion under Reclamation of Stream Channels and Wetlands.
Above-Grade Clay Filled Areas: The three above-grade clay filled areas (1,642
acres) remaining after reclamation would have phosphatic clay both as the back-
fill material and the reclaimed surface soil. This dominance of clay would
result in a reclaimed soil with poor structural stability. Phosphatic clay
soils are best suited to perennial forage crops which require no cultivation
after establishment. Improved pasture would be the initial vegetative cover
for the above-grade clay fill areas. Reforestation strands in reclaimed clay
fill areas would be confined to plantings along the graded remnants of the
waste disposal dike.
Overburden Fill Areas: The 12 overburden fill areas (733 acres) would have
overburden as both the backfill and surface soil material. The areas would be
reclaimed to approximately natural grade and would have good structural sta-
bility and drainage properties. Reclaimed overburden areas could constitute
multi-purpose land suitable for a variety of structural and agricultural uses.
Graded Spoil Areas: Graded spoil areas (838 acres) would have overburden as
the surface soil with no backfill material. Although below natural grade, the
reclaimed areas would be graded to eliminate water pockets and provide drain-
age gradients towards Bowlegs Creek. The areas would have good structural sta-
bility; however, the reclaimed gradients required and the location of the
areas would make them less suitable for structural development than the sand
tailings and overburden fill areas. The favorable agronomic properties of the
overburden would make the areas suitable for improved pasture or silvicultural
uses.
2-96
-------
Disturbed Natural Ground and Miscellaneous Backfill Areas: The reclaimed
plant site area would include both natural ground and the clear water pool
backfilled with overburden. As such, the area would have sufficient load bear-
ing strength to permit unrestricted post-reclamation development. The natural
and overburden surface soils would be capable of supporting agricultural uses
such as improved pasture and silviculture. The initial plan is to reclaim
this area as improved pasture.
Reclamation of Stream Channels and Wetlands: Stream channels and the follow-
ing two types of wetland environment are included in the reclamation plans:
o Shallow depressions near the confluence of restored stream
channels with natural drainage courses
o Below-grade sand/clay and clay landfill areas
Stream Channels: Stream channel reclamation plans provide for the creation of
a normal water level and an associated floodplain. The reclaimed upstream por-
tions of Gilshey Branch, Gurr Run, Stephens Branch and Propps Branch would
pass through reclaimed sand/clay mix areas or clay disposal areas capped with
sand/clay mix. With the exception of Propps Branch, the downstream portions
of all reclaimed stream channels would pass through sand tailings fill areas
capped with overburden (Figure 2.6-H).
The exact location of the reclaimed stream channels would depend primarily on
the internal drainage pattern in each reclaimed area. Since the wastes would
be deposited hydraulically, all sand/clay mix areas and clay settling areas
capped with sand/clay mix would be relatively flat. However, all settling
areas would have gentle gradients from the inlet towards the outlet spillways
which would typically persist after deactivation, although differential sub-
sidence frequently creates shallow depressions. When the volunteer vegetation
is cleared from the waste disposal areas during reclamation, the areas would
be topographically mapped. Using these maps as a guide, the stream channels
would be excavated to follow the prevailing drainage patterns within the
areas. All reclaimed channels would tie in with their undisturbed downstream
portions.
2-97
-------
PROPOSED LOCATIONS AND APPROXIMATE DRAINAGE BASINS
FOR RECLAIMED STREAM CHANNELS
(SAND/CLAY MIX)
Reclaimed Stream
Channels
Š Gllshey Branch
(f) Gurr Run
(3) Stephens Branch
(4) Maron Run
(§) Propps Branch
LEGEND
Out Parcels
(Not Owned By Mobil)
'AJAjl Undisturbed Areas
CS Clay Settling
M Sand-Clay Mix
TF Tailings Fill
OF Overburden Fill
GS Graded Spoils
DP Dredge Pond
SC Sand -Clay
(CS) Final Reclaimed
Land Form
Drainage Basin
Boundary
SOURCE: ZELLAR8-WHLLIAM8
-------
Shallow Depressions: In order to provide additional wetland areas to receive
surface drainage from the reclaimed site, nine shallow depressions are in-
cluded in the reclamation plan; these depressions would be located at the out-
let ends of reclamation areas. The reclaimed wetlands would consist of a
small area of permanently standing water around the overflow drainage swale
surrounded by a larger, gently sloping area that would be seasonally flooded.
Below-Grade Sand/Clay Mix and Below-Grade Clay Filled Areas: Following intro-
duction of backfill, these areas would be drained to promote subsidence of the
fill and formation of a surface crust. The protruding spoil piles would then
be graded into the partially filled mine cuts until the spoils are slightly
below natural grade and slighty above the subsided elevation of the backfill
material. The graded spoil areas are intended for wetland reforestation while
the backfilled interspoil areas with a longer hydroperiod are intended for
marsh reclamation.
Revegetation: The six types of revegetation programs established in the sand/
clay mix reclamation plan are as follows: reforestation along reclaimed
stream channels, wetland reforestation, nonforested wetland revegetation, up-
land mixed reforestation, commercial pine plantings and improved pasture.
Soil differences would influence the location and extent of the various types
of revegetation.
Reforestation Along Stream Channels: The reclaimed stream channels would be
reforested with native tree species in the same manner as discussed in the pro-
posed action. Approximately 263 acres of wetlands would be reforested along
the reclaimed stream channels. The areas include portions of Gilshey Branch,
Gurr Run, Stephens Branch, Propps Branch, Maron Run and several unnamed tri-
butaries to Bowlegs Creek.
Wetland Reforestation: Graded spoil areas within below-grade fill areas of
CS-9 and CS-10 would be reforested as freshwater swamps with native wetland
species. Hydric species would be planted along the margins of the interspoil
marshes, and the species which could not tolerate prolonged flooding would be
planted on the graded spoil. These plantings would be conducted in the same
2-99
-------
manner as the forested stream channels. A total of 746 acres would be refor-
ested in this manner.
Nonforested Wetland Revegetation: Approximately 1,615 acres would be
reclaimed as freshwater marsh areas. These areas would be located in the
interspoil regions within the below-grade settling areas (CS-9 and CS-10) and
shallow depressions found in above-grade settling areas. These areas would be
planted in the same manner discussed under the proposed action.
Upland Mixed Reforestation: Upland mixed reforestation would occur on 1,826
acres. As in the proposed action, these areas would be located adjacent to un-
disturbed forested areas and as elongated strands in the reclamation areas.
In the sand/clay mix plan the potential exists for utilizing both sand/clay
substrate and dike remnants for reforestation. Therefore, at the junction of
various strands, the planting zone would be expanded to form reforestation
blocks. A variety of native hardwood and coniferous trees would be included
in the reforestation plantings. Species such as longleaf pine, live oak and
dogwood would be planted on the well drained sites, while species such as
water oak, laurel oak, sweetgum and slash pine would be planted on the wetter
sites.
Commercial Pine Plantings: Approximately 431 acres would be planted with pine
in the same manner discussed under the proposed action. The locations for
this reforestation include Areas TF-2 and M-4, a slightly smaller total area
than was planned under the conventional reclamation plan. These plantings are
intended primarily to replace the value of existing pine plantations.
Improved Pasture: Improved pasture would be planted throughout the reclaimed
site comprising 10,421 acres. These areas would be revegetated in the same
manner as discussed under the proposed action. As with the sand/clay cap
plan, Coastal and Gallic bermudagrass varieties may be planted in addition to
the Pensacola bahiagrass in some of the better drained sand/clay and overbur-
den soils.
Annual Reclamation Schedule: Table 2.6-5 summarizes the reclamation schedule
for the sand/clay mix case. A total of three years after final fill has been
2-100
-------
TABLE 2.6-5
ANNUAL RECLAMATION SCHEDULE
(Sand/Clay Mix Plan)
Year
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
SOURCE:
Areas Reclaimed
OF-1
OF -2
TF-1
TF-2
OF-3
TF-3, M-3
M-l, M-2, M-4
TF-4, OF-4
TF-5, M-5
OF-5
OF-6
TF-6
OF-7, OF-8, CS-1, CS-2
CS-3, CS-4, GS-1
TF-07, OF-9, CS-5, GS-2
M-6, M-7, GS-3
TF-8, CS-6
OF-10
OF-11, M-8, TF-9
M-9
CS-7, TF-10
M-10
OF- 12
Plant site and ancillary
facilities
M-ll, CS-8
DP-2, CS-9
CS-10, DP-1
ZELLARS-WILLIAMS
Acreage Reclaimed
During Year
33
11
20
218
28
284
405
313
731
66
20
286
2,598
1,221
542
660
55
1,605
410
810
330
120
169
1,520
972
1,767
Reclaimed
Acreage
Cumulative
Total
33
44
64
282
310
594
999
1,312
2,043
2,109
2,129
2,415
5,013
6,234
6,776
7,436
7,491
9,096
9,506
10,316
10,646
10,766
10,935
12,455
13,427
15,194
2-101
-------
allotted to complete reclamation of sand tailings and overburden landfills.
Of this total, two years would be utilized in grading the areas to approved
slopes, establishing drainage and planting a vegetative cover. The third year
would be allotted for the vegetative cover to become established.
A total of five years after final fill is required to complete the reclamation
of sand/clay reclamation areas and clay settling areas capped with sand/clay
mix. Two years would be allowed for the material to conslidate to approxi-
mately 30 percent clay solids. The next two years would be used to grade the
areas to approved slopes, establish drainage and plant a vegetative cover. The
final year would be required to allow the vegetative cover to become estab-
1ished.
After final fill, seven years have been allotted to complete reclamation of
clay settling areas. Of this total, three years would be required for the
areas to consolidate to 22 percent solids; three years would be needed to
grade, establish drainage and plant a vegetative cover; and one additional
year would be required to allow the vegetative cover to become established.
2.6.3.2 Environmental Considerations
Environmental Advantages: The sand/clay mix reclamation plan has the greatest
acreage in both reclaimed wetland areas and reforested stream channels and
reclaimed upland mixed forested areas (equivalent in acreage to the overburden/
clay plan mix). The greater surface area with 2:1 sand/clay mix or overburden
mix would increase the surface permeability and slightly reduce runoff flows
from the site (as compared to the conventional plan).
Environmental Disadvantages: This reclamation alternative would have by a
slight margin the poorest land use potential of all the alternatives (short
and long-term stability). The agronomic value would be second poorest (to the
conventional plan) of the four alternatives. The sand/clay mix plan also has
the second highest potential dike failure risk rating and soil radium concen-
trations of all the alternatives.
2-102
-------
2.6.4 OVERBURDEN/CLAY MIX PLAN
2.6.4.1 General Description
The reclamation plan following overburden/clay mix waste disposal is similar
to the plan developed for the sand/clay mix case. The primary difference from
a reclamation perspective is the increased amount of sand/clay mix acreage and
the associated reduction of uncapped clay filled areas. Both plans provide
for the restoration of 60,000 linear feet of stream channels and approximately
2,493 acres of wetland cover types. The reclaimed site would also have approx-
imately 2,495 acres of upland hardwood and mixed forest. Acreage for the land
use categories are the same as those developed for the sand/clay mix plan
(Table 2.6-6). Stream channel and wetland reclamation would be accomplished
for this reclamation plan in much the same way as the sand/clay cap and mix
plans. Revegetation of the reclaimed areas would be accomplished in the same
manner described in the sand/clay mix plan. All six types of vegetation would
have approximately the same total acreages and the same general site locations
as the sand/clay mix plan. Listed below are the six types of revegetation pro-
grams along with their total acreages and site locations.
Reforestation Along Reclaimed Stream Channels:
Acres - 263
Location - Portions of Gilshey Branch, Gurr Run, Stephens Branch,
Propps Branch, Maron Run and several unnamed tributaries
to Bowlegs Creek, at the approximate locations of the
existing streams.
Wetland Reforestation:
Acres - 746
Location - Graded spoil areas within below-grade fill areas of CS-9
and CS-10.
Nonforested Wetlands:
Acres - 1,615
Location - Interspoil regions within the below-grade settling areas
(CS-9 and CS-10) and shallow depressions found in above-
grade settling areas.
2-103
-------
TABLE 2.6-6
LAND USE CATEGORIES
(Overburden/Clay Mix Plan)
Land Use/Cover
Agricultural Land
Cutover Flatwoods
Upland Hardwoood Forest
Upland Mixed Forest
Planted Pine
Water Areas
Forested Stream Channel
Freshwater Swamp
Freshwater Marsh
Developed Land
Cropland
Total
Acreage
10,421
182
664
1,831
431
3
263
857
1,636
0
0_
16,288
SOURCE: ZELLARS-WILLIAMS
2-104
-------
Upland Mixed Reforestation:
Acres - 1,826
Location - Adjacent to undisturbed forested areas and throughout
the reclaimed areas in elongated strands and junction
blocks at the intersections of the elongated strands
(same as areas found on Figure 2.6-G).
Commercial Pine Planting:
Acres - 431
Location - TF-2 and M-4 (same as areas found on Figure 2.6-G)
Improved Pasture:
Acres - 10,421
Location - Throughout reclaimed site (same as areas found on Figure
2.6-G).
2.6.4.2 Environmental Considerations
Environmental Advantages: This method of reclamation would have essentially
the same advantages as the sand/clay mix plan. One additional advantage would
be the elimination of all above-grade clay settling areas by replacement with
overburden sand/clay mix areas. The greater surface area with 2:1 sand/clay
mix or overburden mix should increase the surface permeability and slightly
reduce runoff flows from the site.
Environmental Disadvantages: The overburden mix plan's disadvantages are
essentially the same as those of the sand/clay mix plan.
2.6.5 SUMMARY COMPARISON
Potential land use is the primary area of concern regarding reclamation.
Based on the different land types resulting after reclamation, a rating system
was developed to compare the soil bearing capacity and agronomic value on a
relative weighted bases for the total site for the proposed action and the
alternative reclamation plans. Each landform was rated on a scale of 1 to 10,
with 10 equivalent to existing conditions based on analysis presented in
Section 3.2 (Geology and Soils). A weighted overall site rating was then
2-105
-------
calculated for short-term and long-term soil bearing capacity value, as well
as for agronomic value. Tables 2.6-7, 2.6-8, and 2.6-9 show these ratings,
respectively.
The conventional reclamation plan, while it is the most proven technique,
carries with it some significant disadvantages. These disadvantages include
the least amount of wetland acreage, the largest acreages of above-grade clay
settling areas and the highest post-reclamation levels of soil radioactivity.
Clay settling areas are also the must difficult to dewater. While the sand/
clay mix plan would have soils with increased fertility and would provide
slightly greater artesian aquifer recharge, the disadvantages associated with
this plan would outweigh the advantages. There would be greater short and long-
term structural stability problems and the reclamation of Propps Branch would
be more difficult in the sand/clay mix due to the instability of the mixture.
The overburden/clay mix plan's advantages and disadvantages are essentially
the same as the sand/clay mix plan. The advantages of the sand/clay cap
reclamation plan significantly outweigh the disadvantages in that the agro-
nomic value of the land is the best of all the alternatives, the radon-226
concentration is half that of the conventional plan and the drainage patterns
would be altered slightly less than the conventional plan. The only apparent
potential disadvantage of any consequence is that the sand/clay cap reclama-
tion techniques have not been fully proven in the industry. In conclusion,
the sand/clay cap reclamation plan is the environmentally preferred
alternative.
2.7 WATER SOURCE ALTERNATIVES
Water management techniques at the South Fort Meade Mine would permit water to
be recovered from ore transportation, washing, feed preparation, flotation
process and waste disposal, thus minimizing effluent discharges and consump-
tive uses. The proposed mine water system is presented in Figure 2.7-A and a
summary of the water balance is presented in Table 2.1-3. Approximately 90
percent (157.2 mgd) of the water uses in Mobil's mining operation would be
supplied from the recirculation system. The South Fort Meade Mine would also
require a water source of 16.413 mgd. Mobil proposes to utilize groundwater
as the source of process water, makeup water, pump seal water and potable
2-106
-------
ro
i
TABLE 2.6-7
LAND USE POTENTIAL EVALUATION SHORT-TERM STRUCTURAL RATING*
Land Type Relative
Rating
Sand Tailings Capped
with Overburden 10
Clay Capped with
Sand Tailings 5
Clay 2
Clay Capped with
Overburden 3
Sand/Clay Mix or Over-
burden Sand/Clay Mix (2:1) 3
Overburden 10
Clay Capped with Sand/Clay
Mix (2:1) ' 3
Clay Capped with
Sand/Clay Mix (4:1) 3
Water 1
Total
lleighted Relative Rating
Conventional Plan
Acres Wt. Value
5,034
1,489
6,681
0
0
477
0
0
1,513
15,194
50,340
7,445
13,362
0
0
4,770
0
0
1,513
7,7,430
5.1
Sand/Clay Cap Plan
Acres Wt. Value
5,079
0
0
590
0
432
0
7,580
1,513
15,194
50,790
0
0
1,770
0
4,320
0
22,740
1,513
81,133
5.3
Sand/Clay Mix Plan
Acres Wt. Value
3,020
0
1,642
0
3,512
1,740
3,185
0
2,095
15,194
30,200
0
3,284
0
10,536
17,400
9,545
0
2,095
73,060
4.8
Overburden Mix Plan
Acres Wt. Values
3,020 30,200
0 0
0 0
0 0
5,492 16,476
1,740 17,400
2,847 8,541
0 0
2,095 2,095
15,194 74,712
4.9
*Short-term soil bearing capacity is defined as the expected soil bearing capacity at the conclusion of reclamation activities.
SOURCE : STUDY DATA
-------
TABLE 2.6-8
LAND USE POTENTIAL EVALUATION LONG-TERM STRUCTURAL RATING*
Land Type Relative Conventional Plan Sand/Clay Cap Plan Sand/Clay Mix Plan Overburden Mix Plan
Acres Ht. Value Acres Ht. Value Acres Wt. Value Acres Kt. Values
Sdnd Tailings Capped
with Overburden
Clay Capped with
Sand Tailings
Clay
Clay Capped with
Uverburden
Sand/Clay Mix or Over-
burden Sand/Clay Mix (2:1)
Overburden
Clay Capped with Sand/Clay
Mix 12:1)
Clay Capped with
Sand/Clay Mix (4:1)
Water
Total
Weighted Relative Rating
10
6
3
5
5
10
4
5
1
5,034
1,489
6,681
0
0
477
0
0
1,513
15,194
50,340
8.934
20,043
a
0
4,7/0
0
0
1,513
B5.600
5.6
5079
0
0
590
0
432
0
7,580
1.513
15,194
50,790
0
0
2,950
0
4,320
0
37,900
1,513
97,473
6.4
3,020
0
1,642
0
3,512
1,740
3,185
0
2,095
15,194
30,200
0
4,926
0
17,560
17.400
12,740
0
1,513
84,921
5.6
3,020
0
0
0
5,492
1,740
2,047
0
2,095
15,194
30,200
0
0
0
27,460
17.400
11,388
0
2,095
88,543
5.8
*Long-term soil bearing capacity is defined as the expected soil bearing capacity ten years after reclamation has been completed.
SOURCE: STUDY DATA
-------
TABLE 2.6-9
LAND USE POTENTIAL EVALUATION AGRONOMIC RATING
Convention^ Plan
Sanrf,C,ay Cap Plan
San./Clay HI, Pl.^
Sand Tailings Capped
with Overburden
Clay Capped with
Sand Tailings
Clay
Clay Capped with
Overburden
Sand/Clay Mix or Over-
T5 burden Sand/Clay Mix (2:1)
2 Overburden
Clay Capped with Sand/Clay
Mix (2:1)
Clay Capped with
Sand/Clay Mix (4:1)
Water
Total
Weighted Relative Rating
naL i ny
9
2
5
9
7
10
7
8
1
MLF e:ť
5,034
1,489
6,681
0
0
477
0
0
1,513
15,194
45,306
2,978
33,405
0
0
4,770
0
0
1,513
87,972
5.8
5,079
0
0
590
0
432
0
7,580
1,513
15,194
45,711
0
0
5,310
0
4,320
0
60,640
1,513
117,494
7.7
3,020 27,180
0 0
1,642 8,210
0 0
3,512 24,584
1,740 17,400
3,185 22,295
0 0
2,095 2,095
15,194 101,764
6.7
3,020
0
0
0
5,492
1,740
2,847
0
2,095
15,194
27,180
0
0
0
38,444
17,400
19,929
0
2,095
105,048
6.9
SOURCE: STUDY DATA
-------
FIGURE 2.7-A
SEEPAGE
LOSSES
MINE WATER SYSTEM
RAINFALL
1
SAND TAILINGS
BACK FILL
AREA
DRAGLINE
MINING AREA
>-
cc
tr
3
0
z
i
CO
PHOSPHATE
WET ROCK
STORAGE
EVAPORATION
1
CLAY DISPOSAL
RECYCLED WATER
HYDRAULIC WATER
PLANT
CLAY WASTE
SEEPAGE
LOSSES
RECYCLED WATER
SEEPAGE
~~"~ LOSSES
FROM POOLS
& DITCHES
-^-NPDES
DISCHARGE
RECYCLED WATER
SOURCE: MOWL
2-110
-------
water. An alternative to the groundwater supply would be the utilization of
surface water sources. Due to the high quality water required for process
water in the flotation system, treatment of the surface water would be neces-
sary. The uses and sources of process and other aqueous streams are provided
in Figure 2.7-A and Table 2.1-2.
2.7.1 GROUNDWATER WITHDRAWAL (MOBIL'S PROPOSED ACTION)
2.7.1.1 General Description
Mobil proposes to withdraw 15.7 mgd of groundwater for flotation process and
makeup water from the Lower Floridan Aquifer utilizing three wells to a depth
of approximately 1,000 feet. Groundwater would also be withdrawn for pump seal
water and potable water from the Upper Floridan Aquifer at a rate of 0.713 mgd
using wells approximately 240 feet deep. The withdrawal points for the Upper
Floridan Aquifer water would change during the life of the mine. The proposed
withdrawal of 16.413 mgd of groundwater was approved by the Southwest Florida
Water Management District (SWFWMD), and Consumptive Use Permit (CUP) No.
205403 was issued to Mobil on October 7, 1980.
2.7.1.2 Environmental Considerations
Environmental Advantages: The use of groundwater to supply the water demands
of the mine would not require the energy and other resources for treatment
facilities. Using groundwater as a supply source (rather than surface water)
would not alter surface water flows of Bowlegs Creek or the Peace River, nor
would the downstream biological communities be affected.
Environmental Disadvantages^ A disadvantage of withdrawing 15.7 mgd from the
Lower Floridan Aquifer would be the dropping of the piezometric surface of the
aquifer (approximately 3.3 feet over the site). The withdrawal of pump seal
water (0.691 mgd) and potable water (0.022 mgd) from the Upper Floridan Aqui-
fer would lower the water level of this aquifer. More energy would be
required to pump groundwater from deep wells than from nearby surface water
sources.
2-111
-------
2.7.2 SURFACE WATER IMPOUNDMENT
2.7.2.1 General Description
Two surface water bodies considered as alternative water sources were Bowlegs
Creek and the Peace River. The 7-day, 10-year low flows in Bowlegs Creek
(zero mgd) and the Peace River (7.1 mgd) are not sufficient to meet the daily
water requirements (16.413 mgd) of the mine. Therefore, an impoundment would
have to be constructed on Bowlegs Creek. This source of water would probably
require augumentation by groundwater withdrawal. The amount of water supplied
by rainfall catchment is considered to be offset by the amount lost to evapora-
tion. Surface water would require treatment to remove organic material and
suspended solids since these pollutants would adversely affect the flotation
process performance and reagent utilization.
2.7.2.2 Environmental Considerations
Environmental Advantages: If surface water were used for water supply, the im-
pacts to the piezometric surface of the Lower Floridan Aquifer would be re-
duced. Reduction in groundwater consumption by use of surface water supply
would reduce the energy requirements for pumping water. The impoundments
created for surface water storage could provide aquatic habitat for wildlife.
Environmental Disadvantages: Construction of surface water impoundments would
encroach on the buffer areas preserved from mining. Withdrawal of surface
water would reduce downstream flows resulting in disturbances of the natural
floodplains, wetland areas, and aquatic systems. Treatment of the surface
water require additional chemicals and energy for treatment and would generate
waste sludge for disposal. In the event of a dam failure, the impounded water
would represent a flood hazard to downstream areas.
2.7.3 SUMMARY COMPARISON
The primary environmental impact associated with utilizing groundwater with-
drawal is the lowering of the piezometric surface of the Lower Floridan
Aquifer. This effect and the demands of other users have been evaluated by
the SWFWMD which is responsible for determining the permissible amounts of
water to be withdrawn by all major users in the SWFWMD region. The fact that
Mobil was granted a CUP by SWFWMD is judged to represent their determination
2-112
-------
that the anticipated effect on the Floridan Aquifer is acceptable. Given all
other environmental considerations relative to the two methods, groundwater
withdrawal is the environmentally preferred alternative.
2.8 PLANT SITING ALTERNATIVES
The desired location for the beneficiation plant should be one that minimizes
matrix pumping distances, minimizes the loss of phosphate resources by occupy-
ing the surface with structures that prevent mining the area, and does not
disturb environmentally sensitive areas.
2.8.1 GILSHEY BRANCH (MOBIL'S PROPOSED ACTION)
2.8.1.1 General Description
The processing plant would be located on the west side of Manley Road approxi-
mately two miles north of County Line Road (Figure 2.1-F). The plant would be
located in an area that is now primarily pasture. The objectives in siting
the plant were to minimize the energy requirements associated with matrix
transfer (by locating at the centroid of the phosphate reserves). The pro-
posed location is the matrix centroid of pumping distances on the site. The
plant site would be adjacent to an existing road providing easy access for
employees and deliveries. This location would be suitable for utilization of
rail transporation (discussed in Section 2.10, Product Transport Alternatives).
2.8.1.2 Environmental Considerations
Environmental Advantages: The Gilshey Branch plant location would be the most
energy efficient since it would utilize the minimum pumping distances. No
environmentally sensitive areas would be destroyed at this location since it
is currently used for pasture. The plant would be an appreciable distance
from any off-site residents; therefore, noise and fugitive dust would not
affect adjacent property owners.
Environmental Disadvantages: The location of the plant would preclude mining
of approximately 1.1 million tons of phosphate reserves under the site.
2-113
-------
2.8.2 OTHER ON-SITE LOCATIONS
2.8.2.1 General Description
The proposed mine site was examined on a conceptual basis for other potential
locations for the beneficiation plant. Placement of the plant site in another
location on the proposed mine site would increase the matrix pumping distur-
bances. Other alternative locations could entail disturbance of environmen-
tally sensitive areas.
2.8.2.2 Environmental Considerations
Environmental Advantages: Location of the plant in an area with lesser phos-
phate reserves would reduce the amount of phosphate resource withheld from
mining.
Environmental Disadvantages: Placement of the plant site in another location
on the proposed mine site would increase the energy requirements of the pump-
ing systems. Some alternative locations would entail disturbance of environ-
mentally sensitive areas. A location nearer the property boundaries could
also cause noise and dust disturbances affecting adjacent property owners.
2.8.3 SUMMARY COMPARISON
The environmentally preferred alternative is the plant siting at the Gilshey
Branch site since it is the most energy efficient location, no environmentally
sensitive areas would be destroyed and noise and dust emissions would not
affect adjacent property owners.
2.9 WATER DISCHARGE ALTERNATIVES
The primary discharge from the mining area would occur from the 45-acre clear
water pool adjacent to the processing facility. Mobil proposes to discharge
water to the Peace River by way of a vegetated outfall ditch constructed paral
lei to the railroad route. An alternative discharge stream is Bowlegs Creek.
The proposed mine would have an intermittent discharge from the clear water
pool primarily between the months of May and October. The discharged volume
is directly dependent on local rainfall trends and is expected to be the
2-114
-------
greatest between June and September, a period when tropical storms are fre-
quent in Florida. During the wet season the normal and maximum discharge
volumes will be 9 mgd and 20 mgd, respectively. These values were derived
from normal and maximum precipitation and evaporation rates for the area,
the maximum areas undergoing mining at any time, and the maximum quantity of
water which would be utilized for processing.
2.9.1 THE PEACE RIVER (MOBIL'S PROPOSED ACTION)
2.9.1.1 General Description
Under the proposed plant siting, the clear water pool discharge would flow
into the Peace River by way of a vegetated drainage swale along the railroad
route. An evaluation of the present surface water characteristics and the
projected characteristics during mining operations (Section 3.5, 2.2.7}
indicates that if the mine effluent were mixed with the Peace River's average
flow between June and September, the concentrations of TSS, total phosphorus
and fluoride would be 30 mg/1, 2 mg/1 and 1.2 mg/1 respectively. These values
are essentially the same as those naturally occurring from the mass loadings
of the existing tributaries.
2.9.1.2 Environmental Considerations
Environmental Advantages: Discharge to the Peace River would not signifi-
cantly alter the concentrations of total suspended solids, total phosphorus,
and fluoride in the river. The average wet season discharge would increase
the average flow of the Peace River by five percent. Discharge to the Peace
River could be done by gravity flow without the additional energy requirements
associated with pumping.
Environmental Disadvantages: Mass loadings from the mine discharge would in-
crease the suspended solids and phosphorous mass loadings in the Peace River
by two percent and the fluoride mass loadings in the Peace River by eight
percent.
2.9.2 BOWLEGS CREEK
2.9.2.1 General Description
Construction of a pump station and a transfer line from the clear water pool
to Bowlegs Creek would be necessary in order to implement this alternative.
2-115
-------
The discharge characteristics would be the same if the discharge were directed
to Bowlegs Creek instead of to the Peace River. The average mine discharge of
9 mgd would increase Bowlegs Creek's flow (between June and September) by 37
percent. An evaluation of the present characteristics of Bowlegs Creek and
the projected characteristics of the creek during mining operations indicates
that concentrations of the several water quality parameters would increase
with the introduction of the mine effluent. When the mine effluent is mixed
with Bowlegs Creek's average flow between June and September the TSS concen-
trations would increase from 10 mg/1 to 14 mg/1, the total phosphorus concen-
tration would increase from 0.24 mg/1 to 0.98 mg/1, and the fluoride concen-
tration would increase from 0.14 mg/1 to 0.64 mg/1.
2.9.2.2 Environmental Considerations
Environmental Advantages: There are no apparent environmental advantages asso-
ciated with discharging to Bowlegs Creek.
Er^v^ronmental Pi sad vantages: The increased flow could cause erosion of stream
channels which would increase turbidity and alter the existing biological
communities. The mass discharges of pollutant constituents could also adverse-
ly affect the water quality and the biota of the creek. This alternative
would also be more energy intensive since it requires pumping the effluent
from the clearwater pool to Bowlegs Creek.
2.9.3 SUMMARY COMPARISON
While there are no advantages to discharging to Bowlegs Creek, there are
several disadvantages including water quality degradation, increased impacts
on the biota, and increased energy consumption. The Peace River would provide
additional dilution to buffer any impacts of the discharge. Therefore, dis-
charge to the Peace River is the environmentally preferred alternative.
2.10 PRODUCT TRANSPORT ALTERNATIVES
The phosphate product would be transported from the South Fort Meade Mine to
Mobil's existing drying facilities in Nichols. Mobil's proposed action is to
2-116
-------
construct a new six-mile railroad spur to the mine site and transport the pro-
duct by rail. An alternative method of shipment is to truck the product as
described below.
2.10.1 RAILROAD (MOBIL'S PROPOSED ACTION)
2.10.1.1 General Description
The wet phosphate rock produced at South Fort Meade would be transferred into
open top, bottom discharge hopper rail cars for transport to an existing facil-
ity at Nichols. During Phase I operations, one train with 33 cars would make
two daily trips between the beneficiation plant and Nichols. During Phase II
operations, the same number of train trips would be required but the train
would have 65 cars. Mobil would construct a 6-mile rail spur from the plant
site to the existing Seaboard Coast Line track (Figure 2.1.F). A bridge
would be built to cross the Peace River and a grade crossing would be required
on Mt. Pisgah Road. The rail cars would be pushed twice each day from the
beneficiation plant to the main track and returned.
2.10.1.2 Environmental Considerations
Environmental Advantages: The train would be an efficient energy user and
could haul 6,500 tons of product for each trip.
Environmental Disadvantages: A train would disrupt traffic at the Mt. Pisgah
Road crossing for approximately six minutes, four times each day and would
generate some minor noise (below 55 dBA at the closest receptor). Tracks, a
bridge, and a grade crossing would have to be constructed. Their construction
would temporarily disrupt terrestrial biota and adjacent land and the aquatic
biota of the Peace River:
2.10.2 TRUCK PRODUCT TRANSPORT
2.10.2.1 General Description
Product transport by diesel engine truck could be accomplished during Phase I
with 25-ton capacity trucks making 260 round trips per day from the South Fort
Meade Mine site to Nichols. During Phase II, 520 truckloads per day will be
necessary. Operation and maintenance of the trucks would require 100 people
for Phase I and 200 for Phase II.
2-117
-------
2.10.2.2 Environmental Considerations
Environmental Advantages: The only apparent advantage is that there would
probably be less volume associated with a truck spill than with a railcar
spill.
Environmental Pi sadvantages: Trucks would require six times the fuel consump-
tion of one train for equal cargos. Air pollution, noise, and safety hazards
generated by 520 truck trips per day would exceed that generated from the
train. Roads and bridges would have to be improved to handle the additional
traffic and would also require increased road maintenance.
2.10.3 SUMMARY COMPARISON
Increased air pollution, noise and energy consumption are overriding disadvan-
tages to truck transport. Therefore, railroad transport of the product is the
environmentally preferred alternative.
2.11 MITIGATION MEASURES
This section presents possible mitigation measures not already included in the
proposed action or alternatives. These measures were developed from input
received from preparers of the various sections of the EIS.
2.11.1 GEOLOGY AND SOILS
Mobil shall employ high profile overburden stacking in the mining of the area
covered by Clay Settling Area 10 (CS-10) to the maximum extent compatible with
toe spoiling of the leach zone. If any increase in waste storage volume is
realized by the use of this technique, it shall be reflected in a lower re-
claimed elevation for the area rather than an increase in clay storage within
CS-10.
2.11.2 BIOLOGICAL RESOURCES
Before beginning any land-disturbing activities, Mobil shall develop a pro-
gram whereby indigo snakes encountered in the work area are captured and
turned over to the Florida Game and Fresh Water Fish Commission (FGFWFC)
Endangered Species Coordinator for relocation to other suitable habitats in
the region. (The technique for handling and keeping this species until the
2-118
-------
FGFWFC arrives is to place the snake in a cloth sack, out of the sun, prefer-
ably in an air conditioned building.) The program shall include informing
Mobil workers of the importance of the indigo snake, familiarizing them with
its appearance and instructing them as to its preservation. In addition, the
gopher tortoise population in the site area shall be protected to the extent
possible. Mobil shall maintain and submit a record of the program to the U.S.
Fish and Wildlife Service office in Jacksonville, Florida.
Mobil shall not conduct any mining, or any activity associated with its mining
operation, within 1,500 feet in any direction of the bald eagle nest located
in T32S, R26E, Section 9. Beginning four years prior to site preparation acti-
vities preceding mining of the areas closest to the eagle nest (to the east,
south and west), Mobil shall provide for a field study to be performed by a
qualified biologist to determine the area(s) being utilized for feeding by the
eagles. Observations shall be conducted from January 1 through April 15 of
the specified year. Since young may or may not be produced in any given year,
Mobil shall attempt to provide data for at least one successful nestling per-
iod during the referenced four years. Specifics of the study shall be coordi-
nated with and reviewed by the USF&WS office in Jacksonville, Florida. If it
appears at the onset of the study year that the subject eagle nest is no
longer in existence, that fact must be confirmed by a letter from the USF&WS.
If the results of the study reveal that the eagles are utilizing an area on
the Mobil property for feeding, Mobil shall preserve that area from distur-
bance.
Mobil shall conduct a monitoring program to assess the wetlands restoration
and re-creation effort at the South Fort Meade Mine. Three wetland re-
creation areas, a depression wetland in sand/clay capped area CS-1, the refor-
ested stream channel of Maron Run, and the forested wetland in area CS-14
shall be monitored for one year according to the following program: (1)
Beginning 12 weeks after completion of the reclamation of each respective
area, the water level shall be monitored biweekly; and (2) Follow-ing the
first full growing season, a biological assessment shall be performed by a
degreed biologist for each of the three areas; the assessment shall include
a listing of wetland plant species present, mapping of their location, a
visual estimate of the amount of cover provided by the wetland species, and
2-119
-------
sampling of the benthic macroinvertebrates to yield a list of the species col-
lected and their density. After the above-described monitoring program is per-
formed for both the sand/clay depression area and the forested stream channel,
one area shall be selected by EPA for long-term monitoring by Mobil. This
long-term monitoring program shall consist of a yearly biological assessment
by a degreed biologist to include the items in (2) above. In addition, in
order to determine the degree of subsidence occurring, if any, the maximum
depth of the marsh depression area relative to a fixed elevation point shall
be monitored quarterly for the life of this permit. Mobil shall submit annual
reports of the described monitoring program to the EPA Region IV Ecology
Branch.
2.11.3 GROUNDWATER
During the mining activities conducted near the Bowlegs Creek preserved area,
Mobil shall monitor the Shallow Aquifer to assess the effectiveness of the
perimeter ditch in preventing dewatering of the preserved area. This moni-
toring program shall consist of using the existing well SA-3 to perform weekly
manual water level measurements during the first sixteen weeks of mining near
Bowlegs Creek and monthly thereafter until the mining pit immediately adjacent
to the preserved area is closed. Mobil shall not allow the Surficial Aquifer
in this preserved area to be lowered more than three feet due to the mining
activities.
2.12 THE NO ACTION ALTERNATIVE
The no action alternative by EPA would be the denial of an NPDES permit for
the proposed project. The effect of permit denial would be to precipitate one
of three possible reactions on the part of Mobil: (1) termination of their
proposed project; (2) indefinite postponement of the proposed project; or (3)
restructuring of the project to achieve zero discharge, for which no NPDES
permit would be required.
2.12.1 Termination Of The Project
Termination of the planned project would allow the existing environment to
remain as described in Section 3.0. However, there would be adverse socio-
2-120
-------
economic effects due to the loss of 175 jobs when the Fort Meade mine is
phased out. Specifically, the meteorologic and noise characteristics are
expected to remain as described in Section 3.1.1. However, air quality
changes may occur due to emissions from new sources permitted in the region in
the coming years or because of changes in fuels used at existing sources. The
geologic features of the site would remain as described in Section 3.2.1, and
the existing soils would continue to support established vegetation, grazing
lands, and limited agricultural crop production.
If the project were terminated, the Mobil site would remain in its present
radiological state, leaving outdoor gamma radiation and radon flux at lower
levels than would be the case after reclamation. Accordingly, any potential
adverse effects that might result from the redistribution of subsurface radio-
activity would not occur.
Termination of the project would also mean no appreciable changes in the
existing withdrawal quantities of groundwater. The hydrologic characteristics
of the Surficial Aquifer, natural groundwater recharge quantities, and base-
flow to local surface waters would be expected to remain as at present.
Groundwater quality under this no action alternative will depend on future
land uses. If land use patterns in the vicinity of the site continue much as
they are, then groundwater quality should also remain essentially as it is
today.
Under the no action alternative of project termination, no appreciable changes
in the existing surface water quantity are anticipated. Surface water quality
will depend on future land use. If land use patterns in the immediate area
remain fairly constant over the next few decades, surface water quality should
remain much as it is today. If other phosphate mining and processing projects
are permitted, surface water streams may show increases in TDS, sulfate,
phosphate, nitrogen, and fluorides.
If the proposed project were terminated, the aquatic environment with its
alternating hydroperiod and tolerant organisms would remain as it now exists
(Section 3.6.1); however, natural succession of marshes into bayheads would in
2-121
-------
time modify some aquatic habitats. The terrestrial ecology of the Mobil site
should remain as now, with most of the site continuing to be used for agricul-
tural purposes including livestock grazing and citrus groves.
If Mobil does not develop the South Fort Meade site as a replacement mine when
the Fort Meade Mine is exhausted, the contribution to the economy of the area
through employment, tax payments and other economic factors will decline and
eventually cease with the completion of mining at the Fort Meade facility.
The $2.5 million annual revenue, generated by the proposed project through ad
valorem taxation and redistribution of sales tax collected in Polk County,
would not materialize. Present land uses would likely continue, but it is
probable that the property value of the site would drop (relative to the value
for phosphate mineable land).
Termination of the project would also preclude the generation of about $5.6
million a year in severance tax, of which 50 to 75 percent would go to the
State General Revenue Fund and the remainder to the Land Reclamation Trust
Fund and the Florida Institute of Phosphate Research. The primary economic
effect of the no-action alternative would be felt by the 175 Mobil employees
dependent for their jobs and income from the Fort Meade mine, scheduled to be
closed in the near future.
Termination of the project would mean that no known or unknown archaeological
or historic sites would be destroyed by the proposed mining. The 15 historic
sites recorded for the mine site would likely remain undisturbed. However,
none of the historic sites identified is considered a prehistoric or historic
resource of National Register quality.
Lastly, the no action alternative of no mining project on the Mobil site would
mean the approximately 77 million tons of phosphate matrix would not be re-
covered in the short term (the next 25 years). This non-renewable resource
would accordingly be unavailable for fertilizer manufacture. Project termina-
tion would also result in a loss of considerable project investment by the com-
pany. While the 77 million tons of phosphate resource would not be recovered
in the short term, they would remain as unmined phosphate reserves. With
depletion of reserves and other restrictions reducing available supplies of
2-122
-------
phosphate rock, fertilizer supplies may become strategically important to the
U.S. in the next century. Therefore, denial of the permit could mean that the
site's phosphate would be conserved and retained as a national resource, while
simultaneously appreciating in value to Mobil.
2.12.2 Postponement Of The Project
If EPA were to deny Mobil's NPDES permit application for the South Fort Meade
Mine, the project might be postponed for an indefinite period of time and then
successfully pursued by either Mobil or another mining company. This might be
expected to occur when, as described above, high grade phosphate reserves are
depleted and the resource retained on the South Fort Meade site becomes ex-
tremely valuable strategically as well as economically. An adverse effect
resulting from postponement of the project would be the delay of socioeconomic
benefits to the county and state in the form of jobs, payroll and taxes.
Mobil would be adversely affected in that its capital investment could not be
realized for an indefinite time.
On the other hand, important benefits could result from project postponement.
Experimentation and research are ongoing in the areas of phosphate recovery
efficiency, waste sand and clay disposal, reclamation, and wetlands restora-
tion and creation. Technological advances could occur in these areas during
the period of postponement which would allow an improved overall project.
2.12.3 Achieving A Zero Discharge
If EPA denies the NPDES permit, Mobil could still execute a mining project
provided the project could be performed with zero discharge to surface waters.
Under zero discharge conditions, neither an NPDES permit nor an Environmental
Impact Statement would be required.
Achieving zero discharge would be extremely difficult, if not impossible, and
would most likely require significantly increased surface impoundment for
storage of water. The problems occurring with increased surface impoundment
would include increased dike heights, probable infringement on presently
designated preserved areas, a less desirable reclamation plan, and more
limited post-reclamation land use potential.
2-123
-------
It should be noted that although the EIS process would no longer be involved
in scrutinizing these changes (should zero discharge be achieved), the appli-
cant would still be subject to the state of Florida Development of Regional
Impact (DRI) process as well as all applicable state and Federal permit
requirements.
2.13 ERA'S PREFERRED ALTERNATIVES, MITIGATING MEASURES AND
RECOMMENDED ACTION
The environmentally preferred alternative, EPA's preferred alternative, and
Mobil's proposed action (including mitigating measures presented as part of
the proposed action), all coincide with respect to the following project
subsystems:
Mining Method (Dragline)
Matrix Transfer (Pipeline)
Processing (Conventional Beneficiation)
Water Sources (Groundwater Withdrawal)
Plant Siting (Gilshey Branch Site)
Water Discharge (Peace River)
Product Transport (Railroad)
Such is not the case for Mobil's proposed action for waste disposal and recla-
mation. The environmentally preferred alternatives and therefore the EPA
preferred alternatives for waste disposal and reclamation are the sand/clay
cap waste disposal case and tie corresponding reclamation plan.
In addition to identifying the environmentally preferred alternatives, EPA's
assessment has focused on developing mitigating measures, not already a part
of the proposed action, which could minimize adverse impacts of the project.
These are discussed in Section 2.11 of the DEIS. EPA has determined that the
identified mitigation measures should be incorporated into the proposed
project. Specifically, EPA recommends the following:
o Practice high-profile overburden stacking to the maximum extent
compatible with toe spoiling of the leach zone.
o A program to reduce impacts on the indigo snake by capturing and
relocating them to other suitable habitats in the region.
2-124
-------
o A program to evaluate and reduce any potential impacts to the bald
eagle nesting approximately 3/8 mile outside the mine site.
o A monitoring program to assess the wetlands restoration and re-
creation effort at the mine site.
o A program to monitor the Shallow Aquifer to assess the effec-
tiveness of the perimeter ditch in preventing dewatering of the
preserved area.
In order to make its determination regarding the NPDES permit application for
the Mobil project, EPA has developed a comparison between (1) Mobil's Proposed
Action, (2) EPA's preferred alternatives and mitigating measures, and (3) the
no action alternative of permit denial by EPA, which could lead to termination
of the project or postponement of the project or modification of the project
such that an NPDES permit would not be required (i.e. achieve zero discharge).
This analysis is presented in Table 2.13-1.
After careful consideration of these alternatives, EPA proposes to issue an
NPDES permit to Mobil for their proposed South Fort Meade Phosphate mine. The
project authorized by the permit shall be the sum of EPA's preferred alterna-
tives (which is Mobil's proposed action except in the case of waste disposal
and reclamation). Further, the permit shall impose as permit conditions all
the mitigation measures identified as part of Mobil's proposed action (Section
2.1 of the DEIS and Chapter 2 of the SID) as well as all the mitigating
measures recommended by EPA.
2-125
-------
TABLE 2.13-1
COMPARISON OF THE ENVIRONMENTAL IMPACTS OF THE ALTERNATIVES
Air Quality,
Meteorology,
and Noise
Geology and
Soils
Radiation
iroundwater
Mobil's Proposed Action
Minor increases in fu-
gitive dust emissions
and emissions from
internal combustion
engines; minor emis-
sions of volatile
reagents; increased
noise levels in the
vicinity of operating
equipment.
Disruption of the
surface soils and over-
burden strata; removal
of 77 million tons
of phosphate rock;
increased loading
to tie Hawthorn of
17 psi ; altering of sue
topography; creation
of appro*imately 7000
* of structurally
sno agronomicaUy In-
ferior lana.
Disruption of the na-
tural distribution of
radioactive material
within the overburden
and Matrix; Increased
gam*a radiation
levels from reclaimed
surfaces and increased
soil radioactivity.
Lowering of the
piezcmetric surface
of the Lower Floridan
Aquifer; lowering of the
Surficiťl Aquifer near
active uln* pus; 47
percent reduction in
natural recharge.
EPA's Preferred Alternatives
The No Action Alternatives
Including Mitigation Measures
Same as Mooil 's proposed
action.
Termination
No change in
meteorology &
noise levels;
possible air
qua] ity changes
from other
sources.
Postponement
Same as Mobil 's
proposed action.
Achieve Zero Discharge
Same as Mobil 's pro-
posed action.
Sane as Mobil's proposed
action except: increased
loading to Hawthorn Forma-
tion of 16 psi; alteration
to topography not as great
(2 ft. less); possible fur-
ther decrease In level of
CS-IO; slightly increase
future effort to recover
phosphate from waste clay;
improved structural and
agronomic characteristics
over tne approximately
7000 A of land.
Sane as Mobi 1 ' s pro-
posed action, except that
reclaimed surfaces
would nave lower overall
soil radioactivity
and gamma radiation levels.
Saw as Mobil's proposed
action, except that a
percned water table would
be established about 5 feet
below tne surface in the
reclamed sand/clay cap
areas.
No change in
geology; no
change in site
soils; preser-
vation of 77
mil 11on tons
of phosphate
rock reserves.
No change In
radiation char-
acteristics
of the site.
No change in
existing
groundwater
quantity or
quality.
Possible in-
creased phos-
phate recovery
and more effec-
tive waste dis-
posal , reclama-
tion, and wet-
lands restoration.
Same as Mobil 's
proposed action.
Possible reduction
in groundwater
withdrawals be-
cause of more
effective dewatering
of waste materials
resulting from future
process development.
Increased dike heights
and water storage capa-
city; infringement on
Bowlegs Cree* preserved
area; less desirable
reclamation plan.
Probable increase in
area covered with waste
clays - the reclaimed
material having the
highest radioactivity
levels.
Possible reduction in
groundwater withdrawals
because of increased
water storage.
Surface Wter
Biology
Human Resources
Disruption of surface
water flows from tne
mine site; minor alter-
ation in flows fol-
lowing reclamation;
degradation of water
charges from tne
me water system.
Destruction of aqua-
tic and terrestrial
nabitats on the nine
site; aquatic habitat
modification due to
reduced surface
water flows and addi-
tion of contaminants;
loss of sone
endangered species
individuals; creation
of modified habitats
fo! looms reclamation.
Setention of existing
;ot>s and develop-
ment of new joss with
comparatively nigh in-
cone-, ad valorem and
sales tax revenue for
Polk County; severence
lax revenue for the state
Land :*t
-------
3.0 THE AFFECTED ENVIRONMENT AND ENVIRONMENTAL
CONSEQUENCES OF THE ALTERNATIVES
The proposed mining and processing of phosphate rock and subsequent recla-
mation of disturbed land would affect the existing conditions at the South
Fort Meade site. This section presents the existing conditions of that
environment as well as the environmental consequences of no action and of the
alternative methods of accomplishing the project goals. The discussion is
arranged by environmental discipline and mining subsystem (mining method,
matrix transfer, etc.) so that the alternative methods for any given subsystem
can be examined to an equal degree, thus providing a basis for comparison.
Only those subsystems having impacts on a given discipline are discussed under
the discipline heading.
The first alternative discussed under each discipline is the no action alterna-
tive, followed by Mobil's proposed action and other relevant alternatives.
For the no action alternative, the assumption is that Mobil would not proceed
with the construction and operation of the proposed mine, and the site would
likely remain as it is in the foreseeable future. The site's phosphate re-
serves are a valuable resource, however, and may be sought through another
proposed action by Mobil or some other phosphate company in the future.
The mining subsystems necessary for the South Fort Meade Mine are shown below.
Alternatives for each subsystem are arranged with Mobil's proposed action
first.
Mining Subsystem Alternatives
Mining Method Dragline
Bucket Wheel
Dredge
Matrix Transfer Pipeline
Conveyor Belt
Truck
3-1
-------
Mining Subsystem
Processing
Waste Disposal
Reclamation
Water Sources
Plant Siting
Water Discharge
Product Transport
Alternatives
Conventional Beneficiation
Dry Separation
Conventional Clay Settling Case
Sand/Clay Cap Case
Sand/Clay Mix Case
Overburden/Clay Mix Case
Conventional Plan
Sand/Clay Cap Plan
Sand/Clay Mix Plan
Overburden/Clay Mix Plan
Groundwater
Surface Water
Gilshey Branch Site
Other On-Site Locations
Peace River
Bowl egs Creek
Railroad
Truck
3.1
METEOROLOGY, AIR QUALITY. AND NOISE
3.1.1 THE AFFECTED ENVIRONMENT
3.1.1.1 Meteorology and Climatology
The proposed South Fort Meade Mine site is located in the subtropical climate
of the South Central District (as defined by the National Weather Service),
which is characterized by hot, humid summers and mild winters. A summary of
the climatological data for the area is shown in Table 3.1-1. Freezing seldom
occurs more than once or twice each year with winter temperatures averaging
about 62°F. During the summer months, the average temperature is typically
81°F. The normal annual rainfall is 53 to 54 inches, and is heaviest during
the months of June through September. The area experiences about 100 thunder-
storms each year with most occurring in the summer. Central Florida's humi- .
dity is moderate to high year-round, as would be expected in an area with high
precipitation and subtropical temperatures. The humidity is usually highest
at dawn (about 90 percent) and lowest in the early afternoon (about 55
percent).
3-2
-------
TABLE 3.1-1
CLIMATOLOGICAL SUMMARY FOR LAKELAND, FLORIDA
CO
CO
Jan.
(Winter)
Temperature ( F)
Absolute maximum
Mean maximum
Mean
Mean Minimum
Absolute minimum
Degree Days (6Ł°F)
Heating
Cooling
Normal Precipitation (In.)
Relative Humidity (X) For Orlando
(Lakeland Data Unavailable)
Morning
Afternoon
Average Hind Speed (MPH)
Miscellaneous (Mean Number of Days)
Clear
Partly Cloudy
Cloudy
Temperature 32°F
Precipitation 0.01 in.
Maximum 24-hour Rainfall
Intensity (inches)
85.0
70.5
60.8
51.0
25.0
188.0
58.0
2.32
87.0
56.0
7.3
10
12
9
1
7
1 yr
4.0
April
(Spring)
95.0
81.8
72.0
62.1
40.0
9.0
219.0
2.57
87.0
45.0
7.7
11
12
7
0
6
5yr
6.5
July
(Simmer)
101.0
90.4
81.6
72.7
66.0
0.0
515.0
8.09
90.0
59.0
5.7
2
18
11
0
18
Recurrence
10 yr
7.5
Oct.
(Fall)
89.0
82.4
74.3
66.1
43.0
0.0
288.0
2.84
87.0
56.0
7.2
12
11
8
0
8
Interval
25 yr
9.0
Annual
86.0
81.3
72.1
62.9
20.0
678.0
3298.0
49.43
88.0
55.0
6.9
100
159
106
2
120
50 yr
10.0
Period of
Record
1941-78
1941-70
1941-70
1941-70
1941-78
1941-70
1941-70
1941-70
1964-78
1964-78
1967-78
1941-78
1941-78
1941-78
1941-78
1941-78
100 yr
11.0
SOURCE: NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION
-------
Air movement over the South Central District is generally constant, with winds
prevailing from the northeast and averaging six miles per hour during most of
the year. Winter cold fronts may generate winds of 20 to 30 miles per hour,
but the highest winds observed in the area are associated with tropical
storms, hurricanes, or tornadoes. Florida typically experiences one or two
tropical storms each year which usually approach the state from the east or
southeast in August and September, shifting to the south or southwest in late
September and October. Tornadoes may be spawned in association with tropical
storms; however, they most frequently occur in the spring. Florida averages
10 to 15 tornadoes each year.
3.1.1.1.1 Dispersion Characteristics of the Local Atmosphere
The joint frequency distributions (calculated from STAR programs) for Orlando
and Tampa, the stations nearest the site, were used to determine dispersion
characteristics of the local atmosphere. Both stations' distributions show a
prevailing wind direction from the north through the east. The Tampa data
show that prevailing wind directions are primarily from the east-northeast
through the east, one-fourth of the observations being from those directions.
Mean wind speeds from both stations are similar, but Orlando reports a greater
percentage of neutral stability conditions, reflecting its more inland weather
regime. The high percentage of stable conditions reported by both stations is
typical for regions in the southeastern United States. Stable conditions,
when vertical disperson of pollutants is inhibited, will tend to increase the
ground level pollutant concentrations originating from ground level sources
while decreasing those from elevated sources.
The mixed layer, defined in terms of the mixing height, is the air space be-
tween ground level and a level aloft through which the atmospheric pollutants
are distributed. The upper limit of the mixed layer is defined by a layer of
relatively stable air which prevents or retards further vertical dispersion of
pollutants. A low mixing height results in a decreased volume within which
3-4
-------
pollutants may be dispersed, causing potentially higher pollutant concen-
trations. Mixing heights for the Mobil site, determined by the Holzworth
method (1972), were found to be moderate (500-700 meters morning and 1100-1600
meters afternoon). Thus, moderate mixing heights and almost constant wind
give the central Florida area, where the South Fort Meade site is located,
ventilation characteristics favorable to the rapid dilution of pollutants.
3.1.1.2 Air Quality
3.1.1.2.1 Air Pollution Control Regulations
There are both Federal and state regulations which may apply to air pollution
control at the proposed South Fort Meade Mine site. Federal regulations
include the following:
Ambient Air Quality Standards (40 CFR, Part 50). All sources of pollution
must comply with Federal ambient air quality standards for sulfur dioxide,
suspended particulate matter, nitrogen dioxide, ozone, hydrocarbons, and
carbon monoxide. The Federal standards for pollutants of concern to the
proposed mine are given in Table 3.1-2.
Prevention of Significant Deterioration (PSD) (Clean Air Act, Part C, 42 FR
5749, 42 FR 5741, 42 FR 57479). This regulation requires that state imple-
mentation plans (SIP's) be revised to include requirements which will prevent
significant deterioration of air quality in areas which meet the ambient air
quality standards (attainment areas). EPA issues the PSD permit if the state
has not been granted this authority (Florida has not been granted authority).
If the proposed new source has the potential to emit 250 tons per year of any
pollutant regulated by the Clean Air Act, excluding fugitive emissions, then a
PSD permit may be required before construction can commence. EPA has deter-
mined that a PSD permit is not required for the South Fort Meade Mine.
Applicable Florida regulations include the following:
Ambient Air Quality Standards (Florida Administrative Code (FAC), Chapter
17-2.06). All sources of air pollution must comply with Florida's ambient air
3-5
-------
TABLE 3.1-2
AIR QUALITY STANDARDS FOR TSP AND S02
AND VEGETATIVE FLUORIDES STANDARD
CO
Parameter
National
(1)
TSP
Annual geometric mean, ug/m
24-hour maximum concentration
(3)
SO.
Florida
(2)
Primary Secondary
75 60
, ug/m3 260 150
80
, ug/m3 385
uq/m3 - 1300
-
60
150
60
260
1300
45
Annual arithmetic mean, ug/m
24-hour maximum concentration* '
3-hour maximum concentration* ',
Vegetative Fluorides, ug/g
(1) 40 CFR 50. Primary standards define the level of quality necessary to protect the public health. Secondary
standards define the level which the EPA administrator judges necessary to protect public welfare, Including the
protection of sensitive vegetaion and other biota.
(2) FAC 17-2.
(3) Not to be exceeded more than once per year.
-------
quality standards for sulfur dioxide, suspended participate matter, nitrogen
dioxide, ozone, hydrocarbons, and carbon monoxide. The Florida standards for
pollutants of concern to the proposed mine are given in Table 3.1-2.
Best Available Control Technology (FAC, Chapter 17-2.03). All new sources
must apply the best available control technology (BACT) to minimize emissions.
Fugitive Particulates (FAC, Chapter 17-2.05(3)). Reasonable precautions must
be taken to prevent and minimize the emissions of fugitive particulate matter
to the atmosphere.
Prevention of Significant Deterioration (FAC, Chapter 17-2.04). PSD is
defined for major new emission sources. If the proposed mine were determined
to be a major new emission source (250 tons per year of any pollutant regula-
ted by the Clean Air Act), a PSD permit would be required. The Mobil South
Fort Meade Mine will not require a PSD permit.
Permitting (FAC, Chapter 17-4.03), Any new stationary source must obtain a
valid construction or operating permit before commencing such activities.
This requires the completion of air pollutant source construction permit
applications for each source.
3.1.1.2.2 Areawide Pollutants of Concern
A summary of both point and area sources of air pollution emissions for the
seven counties in the region was presented in the Central Florida Phosphate
Industry Areawide Impact Assessment Program (EPA, 1978). Hillsborough County
point sources are dominated by the power industry, with the phosphate industry
dominating point sources in Polk County. Emission sources in Manatee,
Charlotte, DeSoto, Hardee and Sarasota Counties are relatively moderate to
insignificant. The primary pollutants associated with the phosphate industry
are total suspended particulates (TSP), sulfur dioxide (SO,,), insoluble
3-7
-------
fluorides and radon-222. These pollutants result from the following
activities:
(1) Sulfur dioxide originates primarily from the burning of sulfur-containing
fossil fuels and the manufacture of sulfuric acid from elemental sulfur
(Pedco, 1976a and EPA, 1977).
(2) Dust is generated by fuel-burning, drying, grinding, and material
transport, as well as by some stages of mining (Pedco, 1975, 1976a,
1976b).
(3) Fluorides arise from various chemical processes, drying and calcining,
fluoride removal for feed preparation, and gypsum and cooling water ponds
at chemical plants (ESE, 1977 and Tessitore, 1975, 1976).
(4) Radon-222 is the radioactive decay product of uranium-238 which is found
in phosphate deposits. The disturbance of the ground formations by
mining activities leads to a redistribution of the uranium and its decay
products (Guimond and Windhame, 1975).
Site-specific data for TSP, SO^ and fluorides are discussed below. Informa-
tion on radon-222 is presented in Section 3.3.1 (Radiation, The Affected
Environment).
Total Suspended Particulates: Five high volume air samplers were operated
at the South Fort Meade site from February 14, 1979, to February 27, 1980, in
order to establish the baseline levels of total suspended particulates (TSP).
During this one-year period, 558 observations were made and all measured con-
centrations of TSP were well below the Florida and Federal ambient air quality
standards (Table 3.1-2). The maximum 24-hour concentration of 72 ug/m3 was
measured between June 26 and July 2, 1979. This value is below Florida's 24-
3
hour maximum standard (150 ug/m ) as well as the national primary 24-hour
3 3
maximum standard (260 ug/m ). The annual geometric mean was 29 ug/m , approx-
3
imately 50 percent of Florida's TSP annual standard of 60 ug/m and about 40
percent of the national primary standard of 75 ug/m .
The TSP data collected at the South Fort Meade Mine site compare favorably
with the data discussed in the Central Florida Phosphate Industry Areawide
EIS (EPA, 1978), closely approximating the values measured in undeveloped
areas. Thus, the baseline TSP concentration measured at the proposed mine
3-8
-------
site can be considered representative of typical undeveloped areas in central
Florida and demonstrates that the location is attaining the state and Federal
air quality standards for this pollutant.
Sulfur Diox1de_: A Thermo Electron Model 43 continuous S02 analyzer was op-
erated at the proposed mine site from June 13, 1979, to February 29, 1980, to
provide background data on S02 concentrations. Out of the 11,336 observa-
tions, none of the measured concentrations of SOp exceeded at any time the
Florida or national standards (Table 3.1-2). The annual mean S09 concen-
3
tration of 6.56 ug/m at the site is approximately 10 percent of the Florida
o
annual standard (60 ug/m ) and 8 percent of the national annual standard (80
ug/m^). The South Fort Meade Mine S02 data are also similar to the data
reported for undeveloped areas (EPA, 1978).
Fluorides: Four sets of vegetation samples from the area surrounding the pro-
posed mine site were analyzed for vegetative fluorides. A total of 24 samples
were collected of pasture grass and citrus leaves and six soil samples were
collected from pasture and citrus areas. None of the vegetative samples or
soil samples exceeded the Florida fluoride standard (Table 3.1-2). The maxi-
mum fluoride level measured at the site was 39.6 ug/g (pasture grass), or 88
percent of the Florida standard of 45 ug/g. The average level for the vegeta-
tive samples was 11.5 ug/g, about 25 percent of the standard and far below
those levels reported for Polk County by EPA (1978). The high fluoride levels
reported by EPA are concentrated about 10 miles north of the proposed mine
site. EPA also reported a tendency toward a decrease in size of those areas
exceeding the 45 ug/g limit, due to better control of fluoride emissions. If
the trend toward lower vegetative fluoride levels continues, lower con-
centrations at the South Fort Meade Mine site would be expected in the future.
3.1.1.3 Noise
Day, evening and nighttime noise measurements were taken at six monitoring
stations on the site between April 13 and 14, 1980 (Table 3.1-3). The
equivalent A-weighted sound levels (l_eq) on the site ranged from 37 to 51 dBA,
while the equivalent day/night A-weighted sound levels (l_dn) ranged from 48 to
55 dBA. These values are at the upper expected range for a rural area.
During the nighttime sampling events, there were no significant differences
3-9
-------
TABLE 3.1-3
NOISE SURVEY RESULTS AT SOUTH FORT MEADE SITE
April 13, 1980 (Sunday)
Leq Ldn
Monitoring Station
(see below)
1
2
3
4
5
6
Station No.
Night
(Sat/Sun)
49
47
16
42
39
45
Day
(Sun)
47
45
45
51
49
49
Evening
41
45
49
39
41
48
Description
(dBA)
55
53
52
48
49
52
April 14, 1980 (Monday)
eq dn
Night
(Sun/Mon)
49
47
47
43
47
47
Day
(Hon)
37
37
39
44
37
36
Evening
41
41
43
49
34
36
55
53
53
50
53
53
Approximately 600 feet south of the end of the southernmost curve in Mt. Pisgah Road. Microphone was even
with first row of orange trees approximately 75 feet from the edge of the pavement. Station was
surrounded by orange groves.
Even with the first row of orange trees on the south side of Mt. Pisgah Baptist Church; approximately 150
feet from the roadway, surrounded by orange groves.
Northeast corner of the intersection of Mt. Pisgah Road and County Line Road. Approximately 50 feet and
102 feet from the respective roadways. Station was one-fourth encompassed by orange groves and
three-fourths by fields, pasture and woods.
Approximately 200 feet north of County Line Road on Manley Road, surrounded by field and pasture.
Three-fourths mile south of Keller Road on gravel road. Area surrounded by orange groves, fields, pasture
and woods.
2,000 feet north of Keller Road on paved road between Sections 14 jnd 15. Microphone was approximately 10
feet from the oavement, adjacent to barbed wire fence, surrounded by field and pasture.
Notes:
(L ) The A-weighted average sound level, in decibels, during a designated time period.
(1. ) The A-weignted average sound level, in decibels, during a 24-hour period with a 10-decibel weight applied to
dn
the nighttime sound levels from 10 p.m. to 7 a.m.
SOURCE: STUDY DATA
3-10
-------
between sound levels recorded on a weekend night versus a weekday night except
at Station 5, the remotest sampling location, where the weekday night sample
L was 8 dBA higher. Variations in the observed nighttime noise levels at
such a remote location are probably due to natural phenomena (wind, insect
activity, etc.). The weekend and weekday L values for the daytime and
evening sampling periods demonstrated no discernible patterns of variation.
3.1.2 ENVIRONMENTAL CONSEQUENCES OF THE ALTERNATIVES
3.1.2.1 The No Action Alternative
The no action alternative would not increase air emissions or noise levels,
and the site's air quality and noise characteristics would likely remain as
they currently are. However, emissions from any new sources in the area
permitted in the future and/or changes in fuels used at existing sources may
change the air quality of the South Fort Meade site.
3.1.2.2 The Action Alternatives Including the Proposed Action
3.1.2.2.1 Mining Method Alternatives
Dragline (Mobil's Proposed Action): The electrically powered draglines would
not generate point source combustion emissions of air pollutants. Small quanti.
ties of fugitive dust may be generated during overburden removal and matrix
extraction, but because these mined materials would be generally wet, dust
emissions would occur only in isolated cases when surface areas become dry.
Vehicular traffic from operations and maintenance personnel on roadways in the
mining area would constitute line sources of air pollutant emissions consist-
ing of carbon monoxide (CO), nitrogen oxides (NOX) and hydrocarbons. Ground
level emissions of fugitive dust would also be generated by this traffic flow.
These impacts would be insignificant since the emissions would be intermittent
and would be confined primarily to the proposed mine site.
The mining method requires that 50-acre parcels be cleared ahead of each drag-
line, which would result in fugitive dust and emissions of particulates, CO,
and hydrocarbons from open burning of vegetative debris. Approximately 30
percent of the total land area at the site (4,500 acres) has vegetation
requiring clearing and disposal. The impact of this clearing would be minimal
3-11
-------
because the emissions would be intermittent and the rural setting would allow
for the rapid dispersion of pollutants. All burning activity connected with
land clearing would be regulated by permits from the state.
According to the results of the noise monitoring program conducted as part of
Estech's environmental assessment (EPA, 1979a), noise levels between 55 and 62
dBA are expected at a distance of 200 feet from an operating electric drag-
line. Under a "worst case" situation (highest recorded sound level on site
and the highest noise level for an operating dragline) an l_dn value of 68 dBA
could occur at the South Fort Meade Mine property line. This maximum noise
level is greater than the U.S. Department of Housing and Urban Development's
(HUD) normally unacceptable threshold of 65 dBA, but less than HUD's unaccep-
table level of 75 dBA. The maximum value is expected to occur off site only
if the dragline is operating 200 feet or less from the property line. Traffic
associated with the construction and operation of the mine would not signifi-
cantly affect the existing noise environment.
Bucket Wheel: The bucket wheel, like the dragline, would be electrically
powered and would not generate point source combustion emissions. However,
the potential for fugitive dust emissions associated with this method would be
greater than with dragline operations since the drier pit conditions required
favor increased wind erosion of the soil. Bucket wheel mining would also
require a larger cleared area than the dragline method, further increasing
fugitive dust emissions. Open burning of vegetation would generate emissions
in approximately the same quantities as the dragline operation. Mining with a
bucket wheel would require additional handling of the overburden through
conveyors which could potentially increase fugitive dust and would generate
greater noise levels than the dragline mining method.
Dredge: The electrically powered dredge would not generate point source com-
bustion emissions of air pollutants. Fugitive dust emissions would be negli-
gible since excavation is done underwater and overburden and matrix are moved
as slurry. Potential dust emissions would be further reduced by the flooding
of the cleared acreage. Open burning of vegetation would generate emissions
in approximately the same quantities as the dragline operation. Mining
by dredge would affect noise levels in the same way as the dragline method.
3-12
-------
3.1.2.2.2 Matrix Transfer Alternatives
Pipeline (Mobil's Proposed Action): No fugitive dust emissions would be as-
sociated with the pipeline transfer of wet slurry. Because the slurry pumps
would be driven by electric motors, pumping would not result in any point
source emissions at the site. The electric booster pumps would be the only
source of noise associated with this matrix transfer system. The noise gener-
ated by the pumps would not contribute to the off-site noise environment for
three reasons: (1) the pumps would be widely spaced along the pipeline route,
(2) the pipeline route itself would be away from the property boundaries, and
(3) the pump stations would be low noise generation sources. A peak sound
pressure level of 68 dBA for the combination of a dragline and slurry pit pipe-
line has been measured (EPA, 1979a).
Conveyor Transport: The potential exists for minor fugitive dust emissions
from the conveyor operation since the surface material could dry at times dur-
ing transfer. Unless the conveyor is contained or covered, fugitive dust emis-
sions would occur along the transport corridor. A conveyor system would gen-
erally be noisier than a pipeline system. Based on a recent study, L. levels
on the order of 70 dBA could occur at a distance of 175 feet from an operating
conveyor (Farmlands, 1981). The principal source of noise from a conveyor
system is the movement of the belts and rollers, generating noise along the
entire length of the conveyor route. Since the route of the conveyor system
would be away from the property boundaries, the off-site exposure to conveyor
system noise should be minimal. Levels on the order of 60 dBA would occur at
1,250 feet.
Truck: Several potential sources of air pollution are associated with this
transfer method. The trucks' engines would exhaust NO , CO, hydrocarbons and
J\
particulate matter during transit as well as during idling periods while wait-
ing to be loaded. Emissions of fugitive particulate matter would be generated
throughout the entire transfer process (truck loading by the dragline, vehi-
cular traffic on the haul roads, erosion losses during open-bed truck trans-
port and truck dumping at the ultimate destination). The continuous construc-
3-13
-------
tion of haul roads to accommodate this transfer method would further increase
the generation of fugitive dust.
The trucks required to move the ore from the mining area to the beneficiation
plant would generate greater noise levels than the other transfer methods.
The magnitude of such noise would depend on the location of the mining area
and the truck transport route. The impact would be greatest during nighttime
hours. Currently there is little truck-generated noise on local roads during
nighttime hours.
3.1.2.2.3 Matrix Processing Alternatives
Conventional Beneficiation (Mobil's Proposed Action): None of the component
operations of conventional beneficiation are considered to be major air pol-
lution sources. There are no combustion sources and no drying processes that
involve the blowing of air through product or waste material. Wind erosion
losses from product dumping into rail cars or pebble storage piles may result
in minor amounts of fugitive dust emissions; however, the use of water as a
transfer medium and the moist nature of the product would prevent fugitive
dust from becoming a problem. The impact of the dust generated would be
negligible by the time it reaches Mobil's property boundary.
Transfer and storage of some of the flotation reagents could result in emis-
sions of volatile organic compounds (VOC). For example, when a kerosene tank
is filled, vapor in the tank headspace would be vented to the atmosphere. Simi-
lar emissions are also possible from storage and transfer of fatty acids,
amines and No. 5 fuel oil. These potential emissions would be quite small, how-
ever, due to the lew vapor pressures of the materials stored on site.
Based on the Estech study, the conventional beneficiation plant is expected to
generate noise levels between 70 and 75 dBA at a distance of approximately 200
feet. The property boundary nearest the beneficiation plant is approximately
3,300 feet away. Noise generated by the operation of the plant would be
attenuated to between 46 and 51 dBA over that distance, not considering the
additional attenuating characteristics of groundcover, foliage, and man-made
3-14
-------
or natural barriers. Therefore, the contribution of the conventional benefi-
ciation plant to the off-site noise environment will not affect even the
nearest potential receptor.
Dry Separation: The dry separation process would create a significant source
of air pollutant emissions as a result of drying large quantities of matrix
which would require combustion of substantial volumes of fuel oil. Combustion
of the fuel oil would generate emissions of S02 dependent on the sulfur con-
tent of the fuel. Some fuel oils are characterized by relatively high concen-
trations of vanadium (approximately 200 ppm) which act to catalyze the forma-
tion of sulfuric acid from S0Ł. The dry separation process thus poses the
added potential for emissions of acid mist, with the attendant plumes of high
opacity. Particulate matter entrained in the dryer exhaust gases would have
to be removed before discharge to the atmosphere. Oxides of nitrogen (NO )
emissions are a major concern from any combustion-related drying process.
The dry separation process requires the use of dry mining matrix transfer
methods which increases the fugitive dust impacts. The crushing and sizing
operations required prior to drying would generate large amounts of fugitive
dust. Blowers used to separate the matrix would add to the levels of TSP near
the plant site.
This beneficiation process has three components that would have high noise
generation potential: a pulverizer, a rotary kiln with a firebox, and an air
fluidized-bed separator. The dry separation process would be noisier than the
conventional beneficiation process; however, it is improbable that off-site
noise levels would reach unacceptable levels.
3.1.2.2.4 Waste Disposal and Reclamation Alternatives
Conventional Clay Settling (Mobil's Proposed Action): Earthmoving operations
would generate fugitive dust and combustion emissions as impoundments are
built, land is leveled and topography is restored. Nine pieces of earthmoving
equipment are projected to be used at the South Fort Meade Mine. Their emis-
sions and associated fugitive dust would rapidly disperse over the open mine
site, resulting in a negligible impact. During the period between mining and
reclamation of any given area, the barren landscape may give rise to fugitive
3-15
-------
dust emissions. The maximum size of this area is estimated to be 745 acres
during Phase II with two working draglines. After one year, revegetation of
the barren areas will occur through natural seeding, providing temporary cover
until reclamation and revegetation.
Mobil proposes to use six scrapers, two bulldozers and one grader, each with a
peak noise level at 50 feet of 87 dBA, 86 dBA, and 84 dBA, respectively.
Using a noise prediction methodology developed by the Federal Highway Adminis-
tration for heavy equipment operation, day-night equivalent noise levels adja-
cent to dam construction areas will increase while such activities are in pro-
gress. Earthmoving equipment for dam construction would normally be operated
during the daytime for 8 to 10 hours each weekday. Dam construction is not
expected to occur any closer than 200 feet from any receptor. During a dam
construction period, therefore, equivalent noise levels 200 feet from a dam
construction site will be approximately 75 dBA, assuming no attenuation due to
groundcover, foliage and man-made or natural barriers. At various locations
adjacent to the site, Ldn values will exceed 65 dBA, a level considered by the
U.S. Department of Housing and Urban Development (HUD) to be "normally unaccep-
table". However, dam construction activities will not cause Ldn values to
exceed 75 dBA, HUD's "unacceptable" level. After completion of a dam wall,
noise levels on adjacent properties will return to preconstruction levels be-
cause the dam walls will, in effect, serve as a sound barrier to subsequent
mine-related noises. The short-term noise impact of waste disposal and re-
clamation activities could be significant for several weeks to nearby resi-
dents. The impacts would be intermittent, however, occurring only during day-
light hours. The long-term noise impact will be negligible.
Sand/Clay Cap: This alternative would have approximately the same air and
noise impacts as the conventional clay settling case.
Sand/Clay Mix: This alternative would have the same impacts on the air re-
sources and noise environment as the conventional clay settling case.
Overburden/Clay Mix: Impacts on the air resources and noise levels would be
greater with this method than the conventional case because of the additional
earthmoving equipment and mixers required.
3-16
-------
3 1 2.2.5 Plant Siting Alternatives
Gilshev Branch (Mobil's Proposed Action): The proposed Gilshey Branch plant
is located at the centroid of pumping distances for the proposed mine site and
adjacent to an existing road which would provide easy access to the processing
plant (Figure 1.0-B). The minor emissions from conventional processing would
not carry beyond the site's boundaries. The location of the plant would have
little or no impact on the noise environment of adjacent off-site property.
nther On-Site Locations: Other on-site plant locations are not expected to
substantially change the emissions from the plant itself, although increased
vehicle traffic miles created by additional travel distances would result in
greater quantities of roadway dust and vehicular emissions. Moving the plant
site closer to the property boundaries would increase the impacts on adjacent
properties.
3.1.2.2.6 Product Transport Alternatives
Railroad (Mobil's Proposed Action): Mobil proposes to transport product on a
new six-mile railroad spur constructed from the beneficiation plant to the
main railroad line west of the mine site (Figure 2.1-1). The train would make
two daily round trips. The nearest residence to the track alignment is 405
feet north of the track with the next closest residence 820 feet south of the
track Based on the "Noise Assessment Guidelines" prepared by HUD, neither
residence location will have an Ldn greater than 55 dBA due to the operation
of the railroad. This value is well below HUD's "normally unacceptable" level
of 65 dBA. The train would emit air pollutants associated with fuel combus-
tion (particulates, NOX> CO and hydrocarbons), but these emissions wou!d have
a minor effect on local air quality.
Truck- Approximately 260 truck trips would be needed to transport the 6,500
^Tof product carried by one train. The trucks would use about six times
the energy required for rail transport and would result in a significant in-
crease in emissions of air pollutants. If all the trucks use State Route 664
to enter and exit the mine site, the traffic-generated noise levels along the
road segment between Mt. Pisgah Road and U.S. 17 would increase above the
3-17
-------
maximum recorded l_dn value of 55 dBA (Table 3.1-3). During the first phase of
operation, L. values would be 65 to 66 dBA 100 feet from the roadway. During
the second phase of mine operation, after mine production has doubled, the Ldn
value at the same distance from the roadway would rise to 70 dBA.
3.2 GEOLOGY AND SOILS
3.2.1 THE AFFECTED ENVIRONMENT
3.2.1.1 Geology
Geomorphology: The proposed South Fort Meade Mine site lies in the Central
Highlands division of the Mid-Peninsular Physiographic Zone. The Polk Upland,
where the proposed mine is located, is a subdivision within the Central High-
lands. The ground-surface elevation of the upland generally ranges between
100 and 130 feet above mean sea level. The predominant structural feature
affecting the area of interest is the Ocala Arch, a regional anticline
(geologic fold) that follows a northwest-southeast line beginning in Dixie
County and extending southward into northeastern Polk County.
Stratigraphy: During the well-drilling program conducted at the proposed mine
site, geologic formations ranging in age from Eocene to Recent were pene-
trated. Beginning with the oldest, the formations are as follows: the Lake
City Limestone, Avon Park Limestone, and the Ocala Group of Eocene age; the
Suwannee Limestone of Oligocene age; the Tampa Formation and Hawthorn Forma-
tion of Miocene age; and undifferentiated elastics ranging in age from middle
Miocene to Recent. A stratigraphic section of the proposed mine site is pre-
sented in Figure 3.2-A.
Solution Features: Karst topography has developed in large portions of north-
ern and central Florida, and an elongate zone of sinkholes penetrates the up-
per geologic units and extends from north-central Florida to the south central
portion of the state, corresponding to the numerous Central Highlands ridges.
The proposed mine site is located approximately 12 miles west of the closest
occurrence of the sinkhole zone in Polk County. The site's topography (as
well as most of the Polk Upland) is due primarily to the erosional effects of
surface water rather than sinkhole development.
3-18
-------
FIGURE 3.2-A
SOURCE
STRATIGRAPHIC SECTION
OF THE PROPOSED MINE SITE
SYSTEM
OUARTERNARY
and
TERTIARY
Ť }
1 ( TERTIARY
1 (
SERIES
RECENT. PLEISTO-
CENE. PLIOCENE
ltd MIOCENE
MIOCENE
OUGOCENE
EOCENE
' *
STRATIGRAPHIC
UNIT
UNDIFFERENTIATED
CLASTtCS
HAWTHORN FORMATION
TAMPA
FORMATION
LIMESTONE UNIT
SAND & CLAY UNIT
SUWANNEE LIMESTONE
OCALA GROUP
AVON PARK LIMESTONE
CRYSTAL RIVER
FORMATION
WILLISTON
FORMATION
INGLIS
FORMATION
LIMESTONE
UNIT
DOLOMITE UNIT
LIMESTONE
UNIT
LAKE CITY LIMESTONE
~^*~- ""
APPROXIMATE
THICKNESS
(F6ET)
45
80 :
105 .
70 >.
90 -
340
. 275
160 ;
240
" -^ ~j
Vt v\ - \X V\ VI VI \i
-* -M W W ^ A
| S S o S <"
AVERAGE DEPTH IN FEET BELOW LAND SURFACE
3-19
-------
The potential for subsidence as a result of mining-induced solution activity
in the area is considered unlikely due to the thickness of clastic units over-
lying solution-susceptible units and the relatively stable and uniformly high
water level elevations. Solution or collapse features are not known to exist
near the proposed mine.
Proposed Mine Site Geology: The ore bearing zones, contained in the lower
section of the undifferentiated elastics, consist of a sandy clay matrix in-
terlayered with phosphate pebbles. This lower section averages 25 feet thick
and is generally overlain by some 20 feet of sandy overburden. The typical
mine excavation would extend approximately 45 feet below present ground sur-
face, terminating at the clay bed overlying the Hawthorn Formation. (See also
Section 3.3 for discussion of the association of radioactive elements with the
phosphate deposits.)
3.2.1.2 Soils
The Soil Conservation Service (SCS) has been compiling extensive information
on the soils in Central Florida and was commissioned to conduct the soils sur-
vey for the proposed South Fort Meade Mine site. The SCS determined that the
soils on the site are typical of those throughout the region. In addition,
core samples were collected at six locations on the site in order to charac-
terize the near-surface soils and project the engineering and agronomic prop-
erties of the reclaimed surface materials. The analyses of the core samples
are presented in Table 3.2-1. The surface soils (0 to 1 foot) were found to
be generally very sandy (94.7 to 98.7 percent), acidic (pH 4.2 to 6.4) and low
in plant available nutrients.
Soil Series: A total of 34 soil series were found on the site (Figure 3.2-B).
Total acreage and relative percentages of each specific soil series are tabu-
lated in Table 3.2-2. Dominant soils include Pomona Fine Sand (3,327 acres),
Myakka Fine Sand (3,144 acres), Ona Fine Sand (1,503 acres) and Zolfo Fine
Sand (1,732 acres). Collectively, these four soil series account for 56 per-
cent of the 17,355 acres mapped.
3-20
-------
TABLE 3.2-1
PARTICLE SIZE DISTRIBUTION AND PLANT AVAILABLE
NUTRIENT ANALYSES OF OVERBURDEN, SAND TAILINGS AND
PHOSPHATIC CLAY SAMPLES
Core Sample
R-3
CO
i
ro
R-6
R-7
Particle Size Distribution
Plant. Available Nutrients
lb/acre)'
Sample
0-1' Overburden
1-15' Overburden
15-16' Overburden
*3!> Mesh Sand Tailings
-3!> Mesh Sand Tailings
Phosphatlc Clay
0-1' Overburden
1-15' Overburden
15-23' Overburden
35 Mesh Sand Tailings
-K Mesh Sand Tailings
Phcsphatic Clay
0-2' Overburden
2-3.5' Overburden
3.5-8' Overburden
B-12' Overburden
12-12.5' Overburden
12.5-21' Overburden
21-25.5' Overburden
+35 Mesh Sand Tailings
-35 Mesh Sand Tailings
I'liosphatic Clay
% Sand
98.75
96.75
92.25
97.50
98.75
**
96.50
94.00
74.50
98.25
97.00
40.00
96.75
94.50
95.50
94.00
96.75
82.50
84.50
98.25
98.50
33.75
X Silt
0.50
1.00
2.50
0.00
0.00
**
1.50
1.50
2.00
0.00
0.00
7.50
1.50
3.00
2.00
4.50
2.75
1.75
2.25
0.00
0.00
2.00
X Clay
0.75
2.25
5.25
2.50
1.25
**
2.00
4.50
23.50
1.75
3.00
52.50
1.75
2.50
2.50
1.50
0.50
15.75
13.25
1.75
1.50
64.25
ŁH
4.2
6.7
6.2
8.5
7.4
**
5.4
5.4
6.3
6.7
6.7
7.1
5.6
5.1
5.2
5.3
5.1
5.0
6.0
6.8
6.5
7.0
Ca
56
872
2,128
7,320
6,560
**
312
104
1,456
6,520
7,800
7,080
168
32
16
40
8
32
792
6,720
6,840
6,h80
Mg
10
103
205
1.572
712
**
25
55
784
120
112
1,728
48
9
12
23
4
166
305
116
68
1,468
P
120
1,600
3,720
1,890
2,370
**
47
400
2,650
2,300
3,670
1,330
155
128
100
234
296
128
930
3,110
2,800
1,330
K
27
14
57
8
7
**
25
20
133
7
8
492
67
53
30
16
5
19
55
8
7
308
-------
TABLE 3.2-1 (Continued)
CO
I
ro
ro
Plant Available Nutrients
Core Sanj>[c Sample
R-9 0-?' Overburden
2-4.5' Overburden
4.6-/.S' Overburden
7.5-12.5' Overburden
ť35 Mesh Sand Tad Ings
-35 Mesh Sand lad Ings
Phosphattc Clay
R-10 0-0.5' Overburden
0. 5-2 ' Overburden
2- 1'j' Overburden
15-20' Overburden
ť35 Mesh Sand ladings
-35 Mosh Sand lad Ings
Phosphatlc Clay
R-ll 0-1 ' Overburden
1-7.5' Overburden
7.5-17 ' Overburden
17-22' Overburden
*35 Mesh Sand Tailings
-35 Mesh Sand TaUlngs
Phospnatlc Clay
Ca - Calcium
P - Phosphorus
K - I'oUssium
Particle
X Sand
96.50
96. K
97.75
93.75
97.50
97.75
23.75
94.75
94.75
92.50
79.75
97.25
97.25
35.00
95.50
93.25
79.00
82.00
98.50
97.76
35.00
Size Distribution
t_s_m
?.50
3.00
1.75
2./5
0.00
0.00
11.00
4.25
2.25
1.25
0.25
0.00
0.00
9.00
2.50
1.75
1.25
3.00
0.00
0.00
7.00
\JiU
1.00
0.75
0.50
3.50
2.50
2.25
65.25
1.00
3.00
6.25
20.00
2.75
2.75
56.00
2.00
5.00
19.75
15.00
1.50
2.25
58.00
EŤ
5.3
5,0
5,4
5.2
6.5
6.8
7.3
6.4
6.0
5.3
5.5
6.3
6.4
7.0
6.2
5.3
5.0
5.0
6.9
6.3
6.6
Ca
WO
24
72
56
6,390
7,760
5,000
1 , 568
184
568
2,072
6,320
7.480
6,520
408
32
88
96
5,480
6,800
6,560
(lb/acre)*
Mj
31
19
12
23
148
108
1,448
412
80
86
229
88
72
1,260
66
26
122
121
76
80
1,532
P
100
44
87
64
2,300
3,020
280
474
220
930
3,720
2,950
3,110
1,100
100
32
24
43
1,830
2,190
1,720
K
24
7
15
21
4
7
148
113
50
25
104
6
4
164
48
17
18
56
6
8
300
* 0.05 N 11C I in O.d?5 N HZ0^ used as the extracting solution
** '..iinpli' lost
SOURCE: ZELLARS-WILLIAMS
-------
SOIL SERIES MAP
APOPKA SAND
CANDLER FINE SAND
POMONA FINE SAND
PITS-DUMPS COMPLEX
12 OUARTZIPSAMMENTS
13 SAMSULA MUCK
SPARR FINE SAND
MYAKKA FINE SAND
19 FLOHIDANA MUCKY FINK SAND
20 FORT MEADE LOAMY FINE SAND
IMMOKALEE FINE SAND
POMELLO FINE SAND
ONA FINE SAND
CHOBEE CLAY LOAM
PLACID FINE SAND
LOCHLOOSA FINE SAND
30 POMPANO FINE SAND
31 ADAMSVH-LE FINE SAND
TOMOKA MUCK
33 HOLOPAW FINE SAND
35 HONTOON MUCK
M BASINGER FINE SAND
38 ELECTRA FINE SAND
WAUCHULA FINE SAND
FELDA FINE SAND
PAISLEY VARIANT FINE SAND
47 ZOLFO FINE SAND
48 MANATEE LOAMY SAND
57 SLICKENS
BRAOENTON FINE SAND
ARENTS
FELDA VARIANT FINE SAND
72 BflADENTON-BLUFF-FELDA
ASSOCIATION
SOIL CONSERVATION
SERVICE
cr>
po
m
CO
ro
-------
TABLE 3.2-2
SOIL DISTRIBUTION
Map Symbol
2
3
7
11
12
13
14
15
17
19
20
21
22
23
24
25
26
30
31
32
33
35
36
38
40
42
44
47
48
57
67
68
71
72
TfTTil
Mapping Unit Name
Apopka Series
Candler Fine Sand
Pomona Fine Sand
Pits-Dumps Complex
Quartz! psanraents
Sansula Muck
Span- Fine Sand
Tavares Sand
Myakka Fine Sand
Floridana Mucky Fine Sand
Fort Heade Lotay Fine Sand
Inookalee Fine Sand
Pomllo Fine Sand
Ona Fine Sand
Chobee Clay Loam
Placid Fine Sand
lochloosa Fine Sand
Ponpano Fine Sand
AdansvUle Fine Sand
Tonoka Muck
Holopaw Fine Sand
Hontoon Muck
Baslnger Fine Sand
Electra Fine Sand
Wauchula Fine Sand
Felda Fine Sand
Paisley Variant Fine Sand
Zolfo Fine Sand
Manatee Loaiy Fine Sand
Slickens
Bradenton Fine Sand
Ar*nts
Felda Variant Fine Sand
Brťd*nton-81 uf f-Fel da
Association
Number of
Acres
92
603
3327
76
68
41
470
596
3144
363
201
680
36
1503
34
555
43
188
350
286
248
152
500
3
23
544
3
1732
19
194
277
35
248
721
17,355*
1 Of Total
Mapped
0.5
3.5
19.2
0.4
0.4
0.2
2.7
3.4
18.1
2.1
1.2
3.9
0.2
8.7
0.2
3.2
0.2
1.1
2.0
1.6
1.4
0.9
2.9
<0.05
0.1
3.1
<0.05
10.0
0.1
1.1
1.6
0.2
1.4
4.1
99.7
Topographical
Features
Hell drained upland
Well drained upland
Nearly level flatwoods
Phosphate mine related
Phosphate mine related
Depressional organic soils
Poorly drained upland
Hell drained upland
Nearly level flatwoods
Depress ional soils
Well drained upland
Nearly level flatwoods
Upland flatwoods
Nearlj level flatwoods
Floodplain
Nearly level flatwoods
Poorly drained upland
Flatwoods and floodplain
Upland flatwoods
Depressional organic soils
Floodplains and flatwoods
Depressional organic soils
Nearly level flatwoods
Upland flatwoods
Nearly level flatwoods
Floodplains and flatwoods
Floodplains
Somewhat poorly drained upland
Depressional soils
Phosphate mine related
Floodplains and flatwoods
Phosphate mine related
Floodplains and flatwoods
Floodplains
* Includes outparcels located within the site
SOURCE: POLK COUNTY SCS
3-24
-------
Soil Associations: A general county-wide study by the SCS grouped the soils
covering the proposed mine site into the following five general soil associ-
ations: Arrendondo-Fort Meade-Astatula (covering 13 percent of the site),
Tavares-Myakka-Pomello (covering less than one percent of the site), Myakka-
Pomello-Basinger (covering 67 percent of the site), Freshwater Swamp (covering
nine percent of the site), and Astatula-Tavares-Basinger (covering 11 percent
of the site). The extent of these associations is shown in Figure 3.2-C.
A description of the properties of each soil association is listed in Table
3.2-3. Approximately 76 percent of the project site is covered by the Myakka-
Pomello-Basinger and Freshwater Swamp soil associations which have severe
foundation limitations for construction of buildings or light industry. The
remaining areas have slight to moderate foundation limitations. The Arrendon-
do-Fort Meade-Astatula and the Myakka-Pomello-Basinger soil associations com-
prise 80 percent of the site. Land within these associations has a high
potential for improved pasture. The land within the Arrendondo-Fort Meade-
Astatula and the Astatula-Tavares-Basinger soil associations has a high po-
tential for citrus production. With the exception of the Freshwater Swamp
soil association, most of the land on the site is a sandy material which has a
high percolation rate and is a poor topsoil. The Arrendondo-Fort Meade-
Astatula, Tavares-Myakka-Pomello, and Astatula-Tavares-Basinger soil associ-
ations are droughty areas while the Myakka-Pomello-Basinger and Freshwater
Swamp soil associations are chacterized by damp to wet soil conditions.
Unique Agricultural Land: Unique farmland has the special combination of soil
quality, location, growing season and moisture supply needed to economically
produce sustained high quality and/or high yields of a specific crop when
treated and managed according to acceptable farming methods (7CFR Part 657).
There are no designated prime agricultural soils on the proposed mine site due
to the lack of fertility, organic composition and other soil properties
required for this category. There are 566 acres of orange groves on the
proposed mine site, of which 446 acres are classified as unique citrus lands.
3-25
-------
SOIL ASSOCIATION MAP
I
CTI
I mile
T32S
T33S
SOURCE: SOIL CONSERVATION SERVICE
(T)Arredondo-Ft. Meade-Astatula
2)TavareŤ-Myakka-Pomello
3) Myakka-Pomello-Baslnger
-x
4jFreťh Water Swamp
S^Aatatula-Tavares-Baslnger
OUTPARCEL8
cr>
-------
CO
I
ro
TABLE 3.2-3
SOIL RATINGS, LIMITATIONS AND FEATURES AFFECTING SELECTED USES BY SOIL ASSOCIATION
Map
Symbol Percent
Soil Association(a>b) figure 3.Z-C) Of Site
Arrendondo-Ft. Meade - 1 13
Astatula
Taveres-Mycikka-
Panello 'i <1
Myakka-Pomello-
Basiftger 3 67
Freshwater Swamp 4 y
Astatula-Tavares-
Basinger 1> H
Community
Development
Potential
Slight
Moderate
Severe
V. Severe
Slight
(a) The overall rating for the association is based on the rating
for oominant soil (soil that makes up the greatest percentage
of the association) or soils, if more than one soil has the
same rating.
(b) Degrte and Kind of Limitations Affecting Selected Uses:
Soil Potential
For Agriculture
Improved
Pasture
High
V. Low
High
V. Low
Low
Citrus
High
V. Low
Low
V. Low
High
Soil Features Affecting
Water Management *
Drainage
NN
NN
CC.WT
WT, FL
NN
Irrigation
UTY, PR
DTY, PR
HT, PK
WT, FL
DTY, PR
(c) High-level management is assumed, which
includes water management.
(d) Abbreviations:
UTY - Uroughty, Ct - Cutbanks Cave, NN - Not
Needed, PR - Percolates Rapidly, WT - Wet, FL -
Slight - soil properties are generally favorable for stated use
and Ťny limitations are minor and easily overcome.
Moderate - some soil properties are unfavorable but can be
overi.otne or modified by special planning and design.
Severe - soil properties are so unfavorable and so difficult
to correct or overcome that major soil reclamation, special
designs, or intensive maintenance is required.
SOURCE: EPA, 1978
-------
3.2.2 ENVIRONMENTAL CONSEQUENCES OF THE ALTERNATIVES
3.2.2.1 The No Action Alternative
The geology and soils resources on the proposed mine site would remain basi-
cally in their present state if the no action alternative is taken. The geo-
logic formations would not be disturbed and the soils would continue to sup-
port pasture grasses, vegetative cover and limited agricultural crops.
3.2.2.2 The Action Alternatives Including the Proposed Action
3.2.2.2.1 Mining Method Alternatives
Dragline (Mobil's Proposed Action): The proposed mining operation would dis-
turb 15,194 acres (93 percent) of the South Fort Meade site. Included in this
area are 566 acres of orange groves of which 446 acres are classified as
unique citrus lands. This represents approximately 0.3 percent of the citrus
producing land in Polk County, Florida.
Mining the site would involve removing the overburden in order to expose the
ore bearing deposit consisting of the lower section of the undifferentiated
elastics zone. The phosphate matrix, averaging 25 feet thick, would be re-
moved to the clay bed overlying the Hawthorn Formation, and the bottom of the
mine excavation would average 45 feet below present ground surface. The void
created by matrix removal would be filled with overburden, sand tailings and
clay wastes. Soils in the disturbed area would undergo major disruption and
loss of identification.
The practice of leach zone management would allow the leach zone material to
be placed in a pocket at the bottom of the mined area (pocket toe spoiling),
to be subsequently covered with overburden spoil. This would minimize the
impact of redistribution of naturally occurring radionuclides during the min-
ing operation and reduce surface radiation levels on reclaimed landforms. (See
also Section 3.3, Radiation.)
Bucket Wheel: Mining with bucket wheel excavators would have similar impacts
on the geology and soils resources as those for the dragline.
3-28
-------
Dredge: Leach zone management could not be achieved with the dredge method of
mining; therefore, radiation levels would be higher in the reclaimed landforms
with this method than with the proposed action. Other impacts would be simi-
lar to the dragline method.
3.2.2.2.2 Matrix Processing Alternatives
Conventional Beneficiation (Mobil's Proposed Action): The beneficiation pro-
cess would remove phosphate product from waste clays and sand contained in the
phosphate matrix. The waste clays would then be piped to storage impoundments
for dewatering. Mobil reports that the mine site contains a total of 150
million tons of phosphate resource. With present technology, phosphate with a
particle size smaller than 200 mesh cannot be recovered. Thus, the mine site
contains 119 million tons of recoverable phosphate (particle size greater than
200 mesh) and 31 million tons of unrecoverable phosphate. Conventional proces-
sing proposed at the South Fort Meade site would extract about 77 million tons
of the recoverable phosphate from the ore, with approximately 42 mill ion tons
of recoverable phosphate lost with the waste clays and sand tailings. This
constitutes an efficiency of 65 percent in recovering the "recoverable" phos-
phate. Mobil is actively pursuing development of advanced process technology
that would allow for recovery of phosphate smaller than 200 mesh. The phos-
phate contained in the waste clays could be reprocessed when such technology
is developed.
Dry Separation: Dry separation involves processing the pulverized matrix
through a fluidized air bed favoring separation of pebble phosphate and clay.
Since the phosphatic ore at the proposed mine is primarily fine material, less
than 48 percent of the recoverable phosphate (57 million tons) could be sepa-
rated through this processing method. The dry waste clays with fines would be
placed in mined areas eliminating the need for above-grade storage. If
advanced phosphate recovery technology becomes feasible, remining and pro-
cessing of the waste clays could be done in the future.
3.2.2.2.3 Waste Disposal Alternatives
Conventional Clay Settling Case (Mobil's Proposed Action): Approximately 50
percent (8,170 acres) of the mine site would be above-grade clay settling
3-29
-------
ponds with an average dam height of 38.7 feet. The increased loading on the
Hawthorn Formation from the above-grade waste storage would average about 17
pounds per square inch (psi). The clay settling areas would contain 58 mil-
lion tons of phosphate resource that could be remined should advanced recovery
technology be developed. The 58 million tons of phosphate would be contained
in a mixture with 74 million tons of clay. This 132 million tons of clay
residue has a ratio of 0.44 tons of phosphate to one ton of clay. This is
termed a concentration ratio and describes the phosphate to total residue
relationship as a decimal fraction. Therefore, the smaller the decimal frac-
tion, the greater the amount of material that would have to be processed in
order to obtain one ton of phosphate.
Sand/Clay Cap Case: The dam heights for the 7,580 acres of clay settling
basins required for this alternative would average 36.7 feet above natural
grade. This is two feet less than the average dike height for the conven-
tional waste disposal case, resulting in an average loading to the Hawthorn
Formation of about 16 psi. The addition of a sand/clay cap to the clay set-
tling basins would slightly increase the future effort required to recover
phosphate from the clay wastes. Mobil could either use earthmoving equipment
to strip off the sand/clay cap, or could remine and process the cap together
with the clay settling basins. In the latter case, the phosphate resource
would be about 60 million tons and the concentration ratio would be 0.35.
Sand/Clay Mix Case: The sand/clay mix case would result in 3,352 acres of
sand/clay mix impoundments and 4,827 acres of clay settling ponds above
natural grade. The average dike height for the 8,179 acres of above-grade
basins would be 35 feet. The increased loading to the Hawthorn Formation
would average about 16 psi. Should advanced phosphate recovery technology
become available, the sand/clay mix areas would be more difficult to reprocess
because of the presence of the additional sand. Considering both the clay
settling and sand/clay mix basins together, the concentration ratio would be
approximately 0.26. Phosphate resources in the clay settling basins and sand/
clay mix basins would be about 65 million tons.
3-30
-------
Overburden Mix Case: Overburden sand would be used to supplement the sand
tailings mixed with clay, resulting in a waste disposal method similar to
sand/clay mix. The average dam height for 8,339 acres of above-grade settling
basins would be 38 feet above natural grade. The increased loading to the
Hawthorn Formation would average about 17 psi. Potential recovery of phos-
phate from waste clays would be more difficult with this case because of the
large volume of sand/clay mix areas. The concentration ratio would be 0.16
for this case. Phosphate resources which would be contained in the sand/clay
mix basins would be about 65 million tons.
3.2.2.2.4 Reclamation Alternatives
The proposed action and alternative reclamation plans consist of different
combinations of nine different types of landforms. A brief description of
these landforms and plant available nutrient analyses are presented in Table
3.2-4. More detailed discussions of the landforms are presented under the
proposed action and each alternative.
Conventional Clay Settling Plan (Mobil's Proposed Action): The conventional
plan provides for the reclamation of all the land disturbed by mining. Acre-
ages of the land areas to be reclaimed are presented below, and characteris-
tics of the reclaimed landforms are discussed in the following subsections.
Reclaimed Landform Reclaimed Acreage
Sand Tailings Fill Areas with Overburden Cap 5,034
Above-Grade Clay Settling Areas (Uncapped) 6,681
Above-Grade Clay Settling Areas with Sand Cap 1,489
Below-Grade Clay Settling Areas 1,513
Miscellaneous Areas (including overburden
fill areas) 477
Total 15,194
Sand Tailings Fill Areas with Overburden Cap: Sand tailings are composed
almost entirely of sand-sized particles, resulting in a reclaimed landform
with good structural stability and internal drainage properties. Sand tail-
ings are low in plant available nutrients with the exception of calcium and
3-31
-------
TABLE 3.2-4
DESCRIPTION OF POTENTIAL RECLAIMED LANDFORMS
Land form
pH Range Plant Available Nutrients
(units) (Ibs/acre)
Descriptive Comments
Sand tailings fill area 4.2 -6.7
with overburden cap
Above-grade clay 5.6 - 7.3
settling area,
uncapped
Above-grade clay 6.3 - 8.5
settling area with
sand cap
8Ťlow-grade clay $.6 - 7.3
settling area
Above-grade clay 6.3 - 8.5
settling area with
sand/clay mix
(4:1) cap
Łi Jfi. L L
451 119 654 41
6,368 1,487 1,152 282
6,833 273 2,628 7
6,368 1,487 1,152 282
6,740 516 2,333 62
Good structural stability
Good internal drainage, very low moisture retention
capacity
Favorable agronomic properties*
Poor structural stability
Excellent moisture and nutrient retention capacity
Subject to waterlogging in wet season
High nutrient availability
Difficult to cultivate
Sand cap enhances structural stability of above-grade
settling areas
Low moisture and nutrient retention capacity
Agronomic properties limited to seasonal forage
production
Designed specifically for wetland reclamation
Consists of areas of open water adjoined by seasonally
flooded zones
Sandy loam soil (standard soil textural classification)
Load bearing capacity greater than clay soils
Not suited for Immediate structural development
but sufficient to support growth of mature trees
Good moisture and nutrient retention capacity
Good internal drainage
Favorable agronomic properties
Above-grade clay
settling area with
overburden cap
Above-grade
sand/clay mix (2:1)
area
Above-grade clay
settling area with
sand/clay mix (2:1)
cap
Overburden fill area
4.2-6.7
6.3 - 8.5
6.3 - 3.5
6.2 - 6.7
451 119 654 44
6,678 676 2,136 99
6,678 676 2,136 99
451 119 654 41
Good moisture and nutrient retention capacity
Poor structural stability
Good nutrient availability
Favorable agronomic properties
Sandy clay loam soil (standard soil textural
classification)
Load bearing capacity greater than clay soils
Not suited for immediate structural development
but sufficient to support growth of mature trees
Good moisture and nutrient capacity
Poor internal drainage
Favorable agronomic properties
Sandy clay loan soil (standard soil textural
classification)
Not suited for immediate structural development
but sufficient to support growth of mature trees
Good moisture and nutrient capacity
Poor Internal drainage
Favorable agronomic properties
Good structural stability
Good internal drainage
Favorable agronomic properties
Abbreviations;
Ca - Caldua
ng - Magnesium
P - Phosphorus
K - Potassium
SOURCE: STUDY DATA
3-32
-------
phosphorus which are provided by the residual phosphate particles. In addi-
tion, sand tailings soils have low retention capacities for moisture and
applied nutrients due to the virtual absence of clay. If left as the surface
soil, these soils would have a low potential for agricultural productivity.
Therefore, all sand tailings fill areas would be capped with overburden to an
average depth of two feet in order to provide a reclaimed soil with favorable
agronomic properties and to bring the reclaimed surface to approximately pre-
mining grade. The overburden soils used for cap material should equal the
existing surface soils in terms of potential agricultural productivity. The
5,034 acres of sand tailings overburden cap area more closely approximates the
premining soil conditions than any other reclaimed landform except for
overburden fill.
Above-Grade Clay Settling Areas (Uncapped): The 6,681 acres of uncapped above-
grade clay fill areas would have phosphatic clay both as the backfill material
and the reclaimed surface soil. These areas would undergo a period of subsi-
dence and the reclaimed soil would have poor structural stability. Without
expensive adaptation such as the use of pilings, these areas would not be
suited for structural development.
Phosphatic clays have some favorable agronomic properties according to Uni-
versity of Florida soil test recommendations. Site-sampled levels of calcium,
magnesium and phosphorus are over ten times the levels considered to indicate
high availability for these essential elements. Levels of available potassium
are at or above the levels considered to indicate a high availability for this
nutrient. Of the major fertilizer nutrients, only nitrogen is deficient in
phosphatic clay soils. The dominance of clay gives excellent moisture and
nutrient retention capabilities. However, this soil is difficult to cultivate
and is subject to waterlogging during the wet season. Because of this, phos-
phatic clay soils are best suited to perennial forage crops which will toler-
ate periodic flooding and which require no cultivation after establishment.
Above-Grade Clay Settling Areas with Sand Cap: The 1,489 acres of capped clay
settling areas would have a sand tailings cap averaging nine feet thick as the
surface soil and clay as the subsurface fill. The sand cap would promote
3-33
-------
consolidation of the subsurface clay fill, enhancing the structural stability
of this reclaimed landform. Sand tailings are agronomically inferior to
phosphatic clay. Plant nutrient application requirements would be high and
forage production would probably be limited primarily to the wet season. The
reclaimed sand capped settling areas on the site would be best suited for use
as improved pasture.
Below-Grade Clay Settling Areas: The 1,513 acres of below-grade clay filled
areas are designed specifically for wetland reclamation. The clay backfill
material would occupy the interspoil depressions and would be partially capped
with overburden graded from adjacent spoils. Drainage outfalls and fill lev-
els would be designed to provide areas of open water adjoined by seasonally
flooded zones sloping up to graded spoil areas which would be inundated only
at high water.
Miscellaneous Areas: These areas would include the overburden fill areas (308
acres), the former plant site (124 acres) and the water pool filled in with
overburden (45 acres). These areas would have soils with structural pro-
perties the same as those presently existing. The areas could support tree
plantings or buildings.
Sand/Clay Cap Plan: This reclamation plan would modify the acreages asso-
ciated with the various reclaimed landforms of the conventional case; however,
the basic layout of basins and fill areas would be essentially the same.
Acreages of the various types of reclaimed disposal areas for the sand/clay
cap plan are presented below and further descriptions of the reclaimed land-
forms are discussed in the following subsections.
Reclaimed Landform Reclaimed Acreage
Sand Tailings Fill Areas With
Overburden Cap 5,079
Above-Grade Clay Settling Areas with
Sand-Clay Mix (4:1) Cap 7,580
Above-Grade Clay Settling Areas with
Overburden Cap 59°
Below-Grade Clay Settling Area 1,513
Miscellaneous Areas
Total 15,194
3-34
-------
Sand Tailings Fill Areas with Overburden Cap: Reclamation of the sand tail-
ings fill areas with overburden cap would be similar to the proposed action
except that an additional 45 acres of this type landform would be included
with the sand/clay cap reclamation plan.
Above-Grade Clay Settling Areas with Sand/Clay Mix Cap: Above-grade clay
settling areas with sand/clay cap would be used for 7,580 acres of the site,
approximately 50 percent of the reclaimed area. The cap would be sand and
clay mixed in a 4:1 ratio, resulting in a sandy loam soil (standard soil
textural classification). Sand/clay mix soils are projected to consolidate
more rapidly and have better load bearing capacity than clay soils. However,
clay settling areas capped with sand/clay mix would still undergo a period of
gradual subsidence. Consequently, clay settling areas capped with sand/clay
mix would probably not be suited for structural development in the immediate
future.
Sand/clay mix soils are expected to be good agricultural soils. In a 4:1
sand/clay mix, the clay component would contribute fertility, moisture holding
capacity and nutrient retention properties to the mixture. The sand component
would serve to alleviate the problems of tillage and poor permeability that
are associated with clay alone. The best agricultural use of sand/clay soils
would have to be determined by experimentation under field conditions, but
improved pasture is a likely choice and the production of row crops such as
vegetables should be feasible. The load characteristics of the 4:1 sand/clay
mix should be sufficient to support the growth of mature trees.
Above-Grade Clay Settling Areas Capped with Overburden: Approximately 590
acres would be reclaimed as above-grade clay settling areas capped with over-
burden. The reclaimed landform characteristics of these areas would be good
moisture and nutrient retention capabilities, poor structural stability, good
nutrient availability and favorable agronomic properties such as tillage.
3-35
-------
Below-Grade Clay Filled Areas: The 1,513 acres of below-grade clay settling
areas would be designed specifically for wetland re-creation. As in the con-
ventional clay settling case, the same acreage of reclaimed wetlands would
replace the existing wetlands.
Miscellaneous Areas: These areas would include overburden fill areas (308
acres) and the former plant site (124 acres). These areas would have soils
with structural properties the same as the existing soils and could support
tree plantings or buildings.
Sand/Clay Mix Plan: This reclamation plan would modify the layout of the
waste disposal areas as well as the acreages of the reclaimed landforms. The
types of reclaimed landforms for the sand/clay mix plan are as follows:
Reclaimed Landform Reclaimed Acreage
Sand Tailings Fill Areas with
Overburden Cap 3,020
Above-Grade Sand/Clay Mix Areas 3,352
Below-Grade Sand/Clay Mix Areas 160
Above-Grade Clay Settling Areas
with Sand/Clay Mix Cap
Above-Grade Clay Settling Areas
Below-Grade Clay Settling Areas
Miscellaneous Areas (Overburden)
Total
Sand Tailings Fill Areas with Overburden Cap: The characteristics of the sand
tailings fill areas with overburden cap would be similar to the proposed ac-
tion. However, there would be approximately 2,000 acres less of this landform
for the sand/clay mix plan.
Above-Grade Sand/Clay Mix Areas: Because of the limited volume of sand tail-
ings available, there would be only 3,352 acres of 2:1 above-grade sand/clay
mix areas for this reclamation plan. According to standard soil textural
classification, sand and clay mixed in a 2:1 ratio is classified as a sandy
3-36
-------
clay loam soil. Loams are defined as soils in which none of the particle size
classes dominate the soil properties. Therefore, the sandy clay loam soil
produced by the sand/clay mix is expected to exhibit a blend of the properties
of sand and clay. Sand/clay mix soils are projected to consolidate more
rapidly and have better load bearing capacity than clay soils. However, the
sand/clay mix fill areas are still projected to undergo a period of gradual
subsidence as the clay component dewaters. Consequently, these areas would
probably not be suited for structural development in the immediate future.
Sand/clay mix soils are projected to be good soils from an agronomic stand-
point. The clay component would provide fertility, moisture holding capacity,
and nutrient retention properties to the mixture, while the sand would serve
to alleviate the problems of tillage and waterlogging that are associated with
clay alone. These soils should be suited for a variety of agricultural uses.
Improved pasture is a likely choice since forage crops can be selected that
would thrive on the reclaimed soils, and the load bearing capacity of the mix
should be sufficient to support the growth of mature trees. As the tillage
properties of the soil improve with the development of soil organic matter,
the production of row crops such as vegetables may become feasible.
Below-Grade Sand/Clay Mix Areas: The 160 acres of sand/clay mix areas would
be designed for runoff retention during the wet season. These areas would be
slightly above the water table and, therefore, subject to desiccation.
Above-Grade Clay Settling Areas Capped with Sand/Clay Mix: Approximately
3,185 acres of land would be reclaimed as above-grade clay fill areas with a
five foot cap of 2:1 sand/clay mix. The surface soil characteristics of the
sand/clay mixture would be similar to the other sand/clay mix areas described
in this reclamation plan. These areas would not be as structually sound as
the sand/clay mix areas.
Above-Grade Clay Settling Areas: Because insufficient sand tailings are avail
able to reclaim all the waste clay areas with a 2:1 sand/clay mix, approxi-
mately 1,642 acres would be reclaimed as above-grade clay settling areas.
3-37
-------
The characteristics of this reclaimed landform would be similar to the descrip-
tion in the proposed action.
Below-Grade Clay Settling Areas: Approximately 2,095 acres of below-grade
clay settling areas would be re-created as wetlands, 582 acres more than the
proposed action.
Miscellaneous Areas: These areas would include overburden fill areas (733
acres), graded spoil areas (838 acres), the backfilled clear water pond (45
acres) and the reclaimed plant site (124 acres). Soils in these areas would
have the same capability as the existing soils have to support tree plantings
or building foundations.
Overburden/Clay Mix PI an: The overburden/clay mix reclamation plan would
utilize overburden sand as a supplement to the sand tailings in order to
produce more sand/clay mix reclaimed landforms. The types of reclaimed
land forms for this method are described in the following subsections and the
acreages are listed as follows:
Reclaimed Landform Reclaimed Acreage
Sand Tailings Fill Areas with
Overburden Cap 3,020
Above-Grade Sand/Clay Mix (2:1) Areas 5,492
Above-Grade Clay Settling Areas with
Sand/Clay Mix (2:1) Cap 2,847
Below-Grade Clay Settling Areas 2,095
Miscellaneous Areas (Overburden) 1.740
Total 15,194
Sand Tailings Fill Areas with Overburden Cap: The sand tailings fill areas
with overburden cap (3,020 acres) would have the same size and characteristics
as those described in the sand/clay mix plan.
Sand/Clay Mix Area: Approximately 5,492 acres, or 36 percent of the reclaimed
land area, would be 2:1 sand/clay mix. The characteristics for the sand/clay
3-38
-------
mix areas would be the same as those described under the sand/clay mix alter-
native case.
Above-Grade Clay Settling Capped with Sand/Clay Mix: Approximately 2,847
acres of land would be reclaimed as above-grade clay fill areas with a five
foot cap of 2:1 sand/clay mix. The surface soil characteristics of the sand/
clay mix cap areas would be the same as described in the sand/clay mix plan.
Below-Grade Clay Settling Areas: The 2,095 acres of below-grade clay settling
areas would be designed for wetland re-creation. This is similar in size and
characteristics to the proposed action.
Miscellaneous Areas: These areas would include overburden fill areas (733
acres), graded spoil areas (838 acres), the backfilled clear water pond (45
acres) and the reclaimed plant site (124 acres). Soils in these areas would
have the same capability as the existing soils to support tree plantings or
building foundations.
3.2.2.2.5 Water Source Alternatives
Groundwater (Mobil's Proposed Action): Groundwater withdrawal for the pro-
posed mining operation would be primarily from the Floridan Aquifer. De-
watering would be conducted in the Surficial Aquifer in the vicinity of the
mining cuts. In no case would the water table be lowered below the limestone
unit; this would protect against any associated collapse of the geologic
formation.
Surface Water: No significant adverse effects on the area's geology and soils
would be expected as a result of using surface water as a source of water
supply for the proposed mining operation.
3.3 RADIATION
3.3.1 THE AFFECTED ENVIRONMENT
Central Florida phosphate deposits originated in the Middle Miocene period
(approximately 20 to 25 million years ago) as a result of undersea pre-
cipitation and deposition of phosphatic minerals. As these minerals generally
3-39
-------
exhibit uranium concentrations several orders of magnitude greater than most
other natural materials, radiation levels elevated with respect to ambient
background levels can result from the mining and processing of phosphate de-
posits. Mining, transporting and processing the phosphate matrix and over-
burden can increase exposure by allowing gaseous and particulate radioactive
materials to become airborne, by increasing the potential for groundwater and
surface water radioactive contamination through leaching and suspension by
runoff, and by introducing radioactive material into the food chain through
the application of fertilizers or the inadvertent contamination of plants by
irrigation water or airborne dust.
The Central Florida Phosphate Industry Areawide EIS and its supplements give
an in-depth description of the nature of radioactivity, its potential environ-
mental effects, its presence in central Florida phosphate deposits, and the
means used for measuring its presence and assessing its effects (EPA, 1978).
The conclusion in the Areawide EIS is that the radioactive isotopes of environ-
mental importance to the central Florida phosphate mining industry are those
in the Uranium-238 decay series. This is because of their abundance in the
soils and phosphate ore, and the tendency of certain daughter isotopes to
accumulate in human tissue and/or be readily transported as a gas.
3.3.1.1 Uranium, Radioactivity and Exposure
The association of uranium with phosphatic mineral deposits is the source of
almost all naturally occurring radiation in these deposits. Uranium-238, com-
prising 99.28 weight percent of mineral uranium, has a half-life of 4.5x10
years, and a specific activity of 0.33xl06 picocuries per liter (pCi/1). Since
uranium-238 1s the parent radionuclide for the entire family of decay pro-
ducts, its specific activity establishes the concentration of its progeny
under conditions of radioactive equilibrium. The nature of radioactive decay
implies that if the parent and its daughter radionuclides are maintained in a
sealed environment, a steady state decay series is reached. It appears that
such equilibrium exists in undisturbed phosphate deposits, at least for the
radionuclides through radium-226.
3-40
-------
The radionuclides in the uranium series of greatest interest to human exposure
are radium-226, its decay product radon-222, and radon's sequential decay pro-
ducts, polonium-218, lead-214, bismuth-214 and polonium-214 (known collec-
tively as the "radon daughters"). Radium-226 is of the same elemental group
as calcium and exhibits a strong tendency to replace calcium in bone and other
environments. It has a relatively long half-life (1,620 years) and may enter
the body through ingestion of food or water containing radium, or by breathing
airborne dust contaminated with radium. While immobilized in the soil, radium-
226 causes radiation exposure by generation of radon-222. This inert gas can
diffuse upwards through the soil and become airborne. In the atmosphere,
radon-222 may be inhaled, increasing radiation exposure to the lungs. The
radon daughters, although they are not gaseous, enter the body primarily
through the lungs as respirable particles generated by the radioactive decay
of airborne radon. These five elemental radionifclides are responsible for the
majority of human exposure to radioactivity associated with phosphate mining.
3.3.1.2 Uranium and Phosphate Deposits
Uranium present in the marine environment in the Middle Miocene period was
deposited along with the primary phosphatic mineral apatite which has a
chemical formula of Ca5(P04)3(F,Cl,OH). Apatite typically exhibits uranium
concentrations of 50 to 200 parts per million, while most other minerals have
maximum concentrations in the phosphatic matrix of a few parts per million
with normal concentrations of a few parts per billion. In contrast, com-
mercial mining of uranium generally exploits ores with uranium concentrations
of 0.1 to 0.4 percent (1,000 to 4,000 parts per million).
The soils above the phosphate deposit (the matrix) are generally mixed strata
of sands and clays exhibiting low concentrations of radionuclides (20 to 30
parts per million). Immediately above the matrix a zone of leached material
is usually, but not always, present. This zone may or may not contain leached
phosphate ore which results from groundwater movement through the phosphate
matrix, converting the matrix to aluminum phosphate. Aluminum oxide is an
undesirable impurity in a phosphate rock product. Where a leach zone has been
created, the uranium concentrations of that zone are higher (100 to 300 parts
3-41
-------
per million) than those in the overburden above it, and the leach zone is
typically not mined. Leach zone material can be segregated from matrix and
overburden and replaced in the bottom of the mine pit where the matrix has
been removed. This process, referred to as leach zone management, serves to
redeposit the more radioactive material at a greater depth.
The phosphate matrix is composed of the phosphatic minerals', quartz sands, and
nonphosphatic clays in roughly equal proportions. Uranium concentrations are
typically 100 to 200 parts per million. Uranium concentrations in the phos-
phate fractions differ greatly. Roessler et al. (1978) found an approximate
20 percent increase in uranium concentration in pebble product over the matrix
and a 20 percent decrease for rock concentrate. Tailings exhibited uranium
concentrations of 12 percent of those in the matrix, while waste clays exhi-
bited uranium concentrations of 10 percent of those in the matrix.
Reclaimed land has the potential to exhibit greater radioactivity than un-
altered land. This potential is affected by such factors as the presence or
absence of leach zones, leach zone management techniques employed, the amount
of overburden present, and the waste disposal/reclamation techniques employed.
Values of various radiological parameters for several types of land are given
in Table 3.3-1. Debris lands show the highest activities, followed by land
reclaimed with waste clays. Debris lands were reclaimed before the develop-
ment of flotation technology to separate the rock concentrates from sand, and
so contain large amounts of phosphate and uranium.
3.3.1.3 Radiation Existing at the Site
Surface and Near-surface Soils: Direct gamma radiation exposure over the pro-
posed mining area was determined by measuring incident gamma radiation with a
portable scintillation meter at intervals of approximately 50 yards along
transects one meter above the ground. The gamma survey showed levels of 3.5
to 5.5 microroentgen per hour (uR/h) over most of the tract with an overall
average of 4.4 uR/h. Increased radiation levels were noted where local geo-
graphy brought deeper strata with greater radioactivity closer to the surface
along creek beds. This increase in radioactivity was around 40 percent along
Bowlegs Creek in the northeastern corner of the site and as much as 400 to 600
3-42
-------
TABLE 3.3-1
SUMMARY OF RADIOLOGICAL CHARACTERISTICS
OF VARIOUS LAND TYPES - POLK COUNTY
co
i
CO
Surface Soil (0-0. 3") Ra
IpCi/g)
Land Type N Mean (range
Unaltered 20 0.6(0.1-3.6)
Umtlned 2 3.2(2.5-4.1)
Radioactive
Fill
Tailings 20 3.2(0.4-9.2)
All 23 5.0(0.8-35.3)
Overburden
Capped and 6 6.8(3.3-14.6)
Mixed Claysbl
Debris 18 9.5(3.4-23.3)
H - Number of sites in summary
Means are geometric means of average values
a) Overburden category includes reclaimed
overburden
Soil Core (0-1. 8m) Ra Gamma Level Radon Flux
(pCi/g) U'R/h) (pCi/Ť2.s)
N Mean (range) N Mean (range) N Mean (range)
18 0.4(0.2-3.1) 9 5(4-7) 17 0.2Ť0. 1-1.7)
2 2.2(1.1-4.4) 19 2 1.3(0.6-2.8)
16 3.1(0.5-8.7) 11 11(6-16) 19 0 . 7( <0 . 1-2 .7 )
24 5.3(1.0-23.1) 16 13(7-33) 27 1 .5( <0. 1-12.8)
6 7.4(2.8-18.3) 6 17(11-24) 6 1.6(0.3-7.2)
18 7.3(3.1-24.7) 8 22(11-54) 15 4.2(1.7-13.7)
for N sites of indicated land type
overburden piles and sand-fill reclamations capped with
b) Clay category includes settled clays areas capped with overburden and/or tailings and clay-sand mixtures capped with
overburden
SOURCE: ROESSLER, 1978
-------
percent along the western edge. These radiation levels are low, representing
only a small increase over the cosmic radiation level of 3.6 uR/h. Comparison
of these data with the typical gamma levels for undisturbed lands in central
Florida (5 uR/h) shows that the South Fort Meade site is generally lower in
surface gamma radiation than similar land types in this region.
Surface soil samples were collected at 16 sites and radium-226 concentrations
were measured. Concentrations ranged from 0.2 to 1.1 pCi/g, with an average
of 0.4 pCi/g. Values generally correlated well with the observed gamma radia-
tion levels. The average is almost identical to the area-wide average for
undisturbed lands (0.6 pCi/g), and the maximum radium-226 content at the South
Fort Meade site is about one third of the maximum observed in central Florida
(3.8 pCi/g).
To determine near-surface soil radioactivity six-foot core samples were col-
lected at nine representative locations on the South Fort Meade site. If the
water table allowed, the cores were sectioned into one-foot segments before
analysis. Again, radium-226 concentrations were low, ranging from 0.2 to 0.4
pCi/g with an average of 0.3 pCi/g for the upper one foot of soil, and ranging
from 0.2 to 1.0 pCi/g with an average of 0.6 pCi/g for the five-foot to six-
foot samples. Typical radium-226 concentrations observed in the area ranged
from 0.2 to 3.1 pCi/g, with an average of 0.4 pCi/g.
The radiological profiles fell into two groupings. One group maintained a
uniformly low activity throughout the six-foot depth, while the other group
exhibited activity that increased slightly with depth. This behavior cor-
related with the two general soil types of the area, one in which the sandy
soil is underlain by clay within the top six feet and one in which it is not.
The deeper sands, with no clay within the top six feet, showed a uniformly low
activity throughout their depth, while those with clay showed a slight in-
crease in radioactivity with depth. In general, external gamma radiation
levels and surface and near-surface soil radium concentrations were low over
the entire site. Some localized areas of significantly higher radioactivity
were present where erosion had brought more active formations closer to the
surface. This is particularly true along some stream beds.
3-44
-------
Mined Section Profile: Cores were drilled through the matrix at six sites in
the study area to evaluate the potential radiological effects of overburden
disruption. Phosphate matrix portions were separated from the overburden and
sampled. The overburden was sectioned and composite samples were also pre-
pared. Although each site exhibited significant differences, a general pat-
tern was shown of low activity (less than or equal to 1.0 pCi/g) at the sur-
face, increasing gradually through the overburden to 1.0 to 8.0 pCi/g above
the leach zone. If present, the leach zone exhibited widely varying radio-
activity (3.0 to 60 pCi/g). In the matrix, however, composite matrix averages
at the six sites ranged from 12 to 22 pCi/g.
Matrix and Fractions; The matrix samples obtained at the six coring sites
were subjected to pilot plant beneficiation, and the various fractions were
analyzed to determine the radium-226 concentrations. These fractions included
a composite matrix sample, phosphate pebble, clays +35 mesh (flotation feed,
concentrate, and tailings), and clays -35 mesh (flotation feed, concentrate,
and tailings). The analytical results for the six locations are presented and
summarized in Table 3.3-2.
The radioactivity of the matrix and its fractions is fairly consistent from
site to site. In general, the matrix averages 16.4 pCi/g and initially sepa-
rates into 37.1 pCi/g pebble, 22.4 pCi/g (dry basis) waste clay suspension and
two flotation feeds. The coarser 28 pCi/g feed yields a 36.5 pCi/g concen-
trate and 11.9 pCi/g tailings; the finer 8.0 pCi/g fraction yields a 28.1
pCi/g concentrate and 2.8 pCi/g tailings.
Deep Section: Baseline radioactivity levels in the strata underlying the phos-
phate matrix were determined by studying the production and monitoring wells
on the tract. The deep section studied extended to a depth of about 1,200
feet. Concentrations of radium-226 in the deep well cuttings ranged from 0.4
pCi/g to 3.7 pCi/g, similar to those observed in the overburden (minus the
leach zone) at the South Fort Meade site.
3-45
-------
CO
I
*>
TABLE 3.3-2
RADIUM-226 CONTENT OF MATRIX AND FRACTIONS
+35 Flotation
Floated
Site
5
6
7
9
10
11
Avg.
Range
Matrix*
13.8
13.7
21.9
20.0
13.1
15.9
16.4
13.1 -
Pebble
39.4
37.0
38.0
35.6
35.1
37.2
37.1
21.9 35.1 - 39.4
Cl^s
15.9
12.1
24.4
45.5
14.8
21.5
22.4
12.1 - 45.4
Feed
29.9
30.7
27.2
24.1
29.2
28.1
2B.2
24.1 - 30.7
Concentrate
36.8
34.1
43.3
36.7
32.7
35.6
36.5
32.7 - 43.3
Tailings
8.7
11.5
15.7
9.5
19.4
6.5
11.9
6.5 - 19.4
Feed
8.3
7.4
10.3
7.1
9.4
7.7
8.4
7.1 - 10.3
_r35 Flotation
Floated
Concentrate
29.9
24.5
33.9
27.4
22.7
30.2
28.1
22.7 - 33.9
Tai
3.5
3.8
3.6
2.1
1.7
2.1
2.8
1.7
lings
- 3.8
* Matrix results are the average of two samples per site, one submitted by Mobil and one submitted by Zellars-Wflliams along
with the benefication fractions
SOURCE: STUDY DATA
-------
Surface Water: Water samples were taken monthly from May to December, 1979,
and were analyzed for gross alpha activity. All samples which exhibited alpha
activity greater than 5.0 pCi/1, plus sufficient additional samples to com-
prise 25 percent of the total samples collected, were analyzed for radium-226
concentration. In general, the surface water radioactivity was low. Approx-
imately 30 percent of the samples exhibited activities below the minimum detec-
table level (about 1.0 pCi/1), and the overall average was less than 1.7
pCi/1. Significant variability between sampling sites and a slight tendency
for higher radioactivity in the winter months of the year were noted. Sedi-
ment radium-226 concentrations also were quite low, averaging 2.6 pCi/g,
although the range was from 0.3 to 12.9 pCi/g. The highest average alpha
activity was noted at the station with the highest sediment radium concen-
tration, indicating a relationship between water radioactivity and suspendable
particulate content that was substantiated by the low levels in both water and
sediment at many of the other stations.
Groundwater: Groundwater samples were collected during the early part of 1980
and again during the fall of 1980 to determine background radioactivity con-
centrations at the South Fort Meade site. Radium-226 concentrations were
determined only for those samples where gross alpha radioactivity approached 5
pCi/1. (These data are reported in Table 3.4-1 of Section 3.4.3, Groundwater
Quality.)
Groundwater radioactivity levels in the Surficial Aquifer at the South Fort
Meade site were extremely variable; gross alpha radioactivity levels ranged
from less than 0.4 pCi/1 to 97.4 pCi/1. For those samples where radium-226
was detected, concentrations ranged from 1.1 to 14.6 pCi/1. The highest
radioactivity levels occurred in samples with high total solids concentra-
tions. It is likely that the high radioactivity levels in the Surficial
Aquifer groundwater are due to high suspended solids concentrations. Surface
water radioactivity discussed in the previous section also indicated higher
radioactivity when higher concentrations of suspended particles were present.
Three groundwater samples exceeded EPA's gross alpha radioactivity standard
3-47
-------
for drinking water (15 pCi/1), and two exceeded the EPA standard for radium-
226 (5 pCi/1).
Groundwater samples from the Upper Floridan and Lower Floridan aquifers exhib-
ited gross alpha radioactivity levels of 48.4 and 34.3 pCi/1, respectively.
Although these values exceed the EPA drinking water standard of 15 pCi/1, the
radium-226 concentrations of 4.4 and 2.3 pCi/1 for the same samples are typi-
cal of Upper and Lower Floridan groundwater in the unmined, mineralized
regions of central Florida (EPA, 1978).
Radionuclide Uptake in Biological Systems: A limited study was undertaken to
determine the biological uptake of radium-226 by biological sampling at the
unmined South Fort Meade site and a reclaimed site known as the Homeland
tract. Radium-226 concentrations were determined for beef, soil, grass, vege-
table and citrus samples by the method of direct gamma spectrometry. However,
radioactivity levels in the tissue and vegetation samples were at the lower
limit of detection for the analytical method employed, and the data have such
a large standard deviation and low confidence level that no conclusions could
be reached regarding differences between premining and postmining radionuclide
uptake.
3.3.2 ENVIRONMENTAL CONSEQUENCES OF THE ALTERNATIVES
3.3.2.1 The No Action Alternative
Under the no action alternative the South Fort Meade site would remain in its
current state. Subsurface radioactivity would remain concentrated in the ma-
trix and the leach zone instead of being redistributed to soils nearer the
surface. Thus, the expected outdoor gamma radiation levels and the Rn-222
flux would be lower than would be expected to occur after mining and reclama-
tion. Structures, including residences, would have lower indoor concentra-
tions of radon progeny on undisturbed land than on reclaimed land. Occupa-
tional radiation exposures resulting from phosphate mining and beneficiation
would not occur, and additional exposure to residents near the mining and
processing operations (due to inhalation of particulates) would be avoided.
3-48
-------
3.3.2.2 The Action Alternatives Including the Proposed Action
3.3.2.2.1 Mining Method Alternatives
Dragline (Mobil's Proposed Action): The use of a dragline to remove over-
burden and matrix ore would have several potential radiological impacts. Each
dragline would dig a series of parallel cuts up to one mile long and approxi-
mately 330 feet wide, and the overburden, typically containing low levels of
radionuclides (1 to 8 pCi/g), would be placed in a previously mined area.
Mobil would practice leach zone management by placing the radioactive leach
zone material (3 to 60 pCi/g) in a pocket at the bottom of the mined-out area
(pocket toe spoiling), subsequently covering the leach zone material with over-
burden. This would minimize the impact of redistributing naturally occurring
radionuclides during the mining operation and would reduce surface radiation
levels on reclaimed landforms.
A moderate amount of dewatering of the mining cut is required for dragline
safety and the optimum recovery of matrix. This dewatering is not considered
to have a major radiological impact (EPA, 1978). The potential occupational
radiation exposure to phosphate miners is low. Prince (1977) measured radia-
tion levels in the vicinity of draglines to be about 5 uR/h (as compared to
the average 4.4 uR/h baseline measured at the South Fort Meade site).
Radiation standards for exposure to Rn-222 and its snort-lived daughters are
expressed in terms of working level (WL) concentrations. One WL is the amount
of any combination of short-lived radioactive daughters of Rn-222 in 1 liter
of air that will release 1.3 x 105 MeV of alpha energy during their decay to
Pb-210. Radon progeny concentrations were found to be low (0.0004 WL) in the
actively mined areas. In comparison, these exposure levels are far lower than
measured values for slab-on-grade structures on unmined land in Polk County
(0.001 to 0.032 WL).
Bucket Wheel: Radiological impacts from the use of bucket wheel excavators
would be similar to those experienced with the use of draglines. Bucket wheel
excavators can be very selective and would be capable of performing leach zone
management.
3-49
-------
Dredge: The use of dredges to remove the overburden and mine the phosphate
ore would have several radiological effects not present with the dragline
method. Selective leach zone removal and placement would be impossible to
practice using the dredge due to indiscriminate placement of leach zone
material in the spoils area. Radiation levels in the reclaimed landforms
would thus be greater with this method than with the dragline method. The
water used to transport the overburden and leach zone material could increase
in radioactivity due to the presence of suspended radioactive particles.
These suspended particles would enter the recirculation system and perhaps
elevate radiation levels in the waste disposal areas and water discharge.
3.3.2.2.2 Matrix Processing Alternatives
Conventional Beneficiation (Mobil's Proposed Action): Conventional processing
of slurried matrix would redistribute naturally occurring radionuclides
between products and wastes. Pilot scale beneflciation of South Fort Meade
matrix was performed to examine this redistribution. As shown in Figure
3.3-A, slurried matrix contained an average of 16.4 pCi/g of radium-226. The
slurry was processed in a washer plant where a pebble product was separated
from the flotation feed and waste clays. Projected radium-226 in the pebble
product was 37.1 pCi/g; waste clays contained an average of 22.4 pCi/g.
The coarse feed was processed further in a flotation plant where it was
separated into a concentrate product averaging 36.5 pCi/g and sand tailings
averaging 11.9 pCi/g. The fine feed fraction was separated into a concentrate
product (28.1 pC/g) and sand tailings stream (2.8 pCi/g). The composite sand
tailings stream contained an average radium-226 concentration of 3.9 pCi/g.
The radioactivity levels of the fractions determined in the pilot-scale benefi-
ciation test were variable, as shown below, with the exception of the level of
the pebble product. Radium-226 concentrations in the proposed mine's phos-
phate matrix, products, sand tailings and waste clays appear to be somewhat
3-50
-------
FIGURE 3.3-A
SCHEMATIC DIAGRAM OF
BENEFICIATION AND ASSOCIATED RADON-226
LEVELS FROM PILOT PLANT TESTS
MATRIX
16.4 pCI/g
WASHER PLANT
PEBBLE PRODUCT
37.1 pCI/g
FLOTATION FEED
CLAYS
22.4 pCi/g
FLOTATION PLANT
CONCENTRATE
COARSE - 36.6 pCI/g
FINE - 28.1 pCI/g
SAND TAILINGS
3.9 pCI/g avg.
COARSE - 11.9 pCi/g
FINE - 2.8 pCI/g
SOURCE: MOSUL
3-51
-------
lower than the average for the area. The following chart compares the South
Fort Meade values to those reported for central Florida (Roessler, 1979):
South Fort Meade Central Florida
(pCi/g) (pCi/g)
Avg. Range Avg. Range
Matrix 16.4 10.7-22.1 37.6 18.1-184.2
Pebble 37.1 35.1-39.4 57.4 44.5-96.6
Rock Concentrate 32.3 22.7-43.3 37.1 26.0-50.7
Clay 22.4 12.1-45.4 52.0 -
Sand tailings 3.9 1.7-10.3 5.2 1.7-12.2
Wet processing of the slurried matrix during conventional beneficiation has
little potential for the generation of airborne radioactivity associated with
particulates. Radiological exposure due to the release of particulate
material during processing is considered negligible.
The external gamma radiation levels in beneficiation plants have been reported
to be about twice the background levels (Prince, 1977). However, results of a
work-station survey found occupancy factors low enough to reduce annual expo-
sures to insignificant levels. Radon progeny concentrations were below the
levels reported for slab-on-grade structures on unmined land (0.0007 WL).
Therefore, the radiological impacts to operating personnel at the plant should
be minimal.
Wet rock storage piles have been reported to yield gamma radiation at an
average rate of 67 uR/h (Prince, 1977). However, occupancy factors around
such piles are extremely small, making the annual exposure to an Individual
insignificant. Wet rock storage and transfer tunnels (located under wet rock
piles) were found to be the most serious radiological hazard areas. WL
measurements at 11 sites in the Central Florida Phosphate District were be-
tween 0.0007 WL and 0.096 WL (Prince, 1977).
3-52
-------
Dry Separation: The dry separation process would have the potential for
generating large amounts of clay- and dust-size particulates which could lead
to exposure to radiation through inhalation. Greater exposure to radiation
would be expected from the use of the dry-separation process than from the
conventional beneficiation process.
3.3.2.2.3 Waste Disposal and Reclamation Alternatives
Conventional Clay Settling Plan (Mobil's Proposed Action): The two major
types of wastes requiring disposal would be clay and sand tailings. As was
discussed in the section on processing, waste clays at the South Fort Meade
site have a much higher average radium-226 level (22.4 pCi/g) than the sand
tailings (3.9 pCi/g). The method of disposal and land reclamation would
determine future surface radium-226 concentrations. Table 3.3-3 presents the
acreages associated with each reclaimed land type and the estimated radiolo-
gical characteristics for the conventional clay settling case. The soil
radium-226 levels shown are for the top two feet of reclaimed land. Gamma
radiation levels were estimated by the method in Report No. 45 of the National
Council on Radiation Protection and Measurements (NCRPM, 1975). No average
gamma radiation level was determined for the below-grade clay settling areas
since the level is dependent on the amount of water present. Submerged clay
settling areas are expected to exhibit little or no gamma radiation due to the
attenuation of water. Pocket toe spoiling would prevent the leach zone
material from affecting the surface radiation levels.
A major problem discussed in the Areawide EIS is the potential hazard of expo-
sure to indoor radon progeny measured as WL within slab-on-grade residential
and public structures. Should buildings be located on the reclaimed site,
indoor radon and radon progeny concentrations would be higher in these struc-
tures than outdoors. Two WL standards have been proposed for existing homes:
(1) a 0.029 WL total exposure including background (Florida Department of
Health and Rehabilitation Services, 1975) and, (2) a 0.020 WL total exposure
including background (EPA, 1979b). The reclamation processes and undeveloped
lands were not addressed in detail in EPA's 1979 recommendations to the
Governor of Florida (EPA, 1979b). However, the following specific guidance
3-53
-------
TABLE 3.3-3
ESTIMATED RADIOLOGICAL CHARACTERISTICS FOR RECLAIMED LANDS
(Conventional Plan)
W
I
land for* Acreage
Sand lailings Capped with b,OJ4
Overburden
Overburden Fill 4//
Abuve-brade CUy b,bŤl
Settl ing Areas
Above-Grade Clay Capped 1,4B1J
with Sand lai) ings
Below-Grade Clay l.bU
Settling Areas (Wetland)
(idllllld
Radiation i°'l Kad'wi-226 Kddon/lux
(uR/hr) (pCi/g) (pCl/iii /sec)
b (4-/) 3 (i!-4) O.b/3
b (4-/) 1 () 4.38
y (7-11) 3 (2-4) 2.Ub
(4-Bb)* 22 (12-4b) 4.J8
Working Level
(ML)
0.0082
0.0068
0.0172
o.om
0.0172
is shown in ( ).
Calculation source fur radon Itux dml working level: "Ndtiondl Kddiation txposure Assessment: Radio-
dctivity of Lands diid Associated Structures," rinal Report Volu:ie 2, February iy/8, C.E. Roessler. J.A.
Methinijton, Jr., and W.E. Uolch.
Calculdtion source for gauiiid rddiation: "National Council on Radiation Protection and Measurements"
Naturdl Background in the United Stales, Report No. 4b, November I97b.
Values tor Kddiuin-i'ilt) represent the top two luet of material . Calculated from soil characterization.
* The below-grade clay settling areas would be reclaimed as wetlands. The fjamma radiation level would
vary depending on the depth of water over the soil surface.
-------
was provided for new homes on any reclaimed, debris and unmined lands which
contain phosphate resources:
"IV. Development sites for new residences should
be selected and prepared, and the residences so
designed and sited, that the annual average indoor...
Working Levels...do not exceed...background
levels..." (EPA, 1979b).
If the final guidance for reclaimed lands is similar to the recommendation
quoted above, then the upper limit of predicted WL's in slab-on-grade homes
will be approximately 0.009 WL (normal background of 0.004 WL plus the uncer-
tainty of 0.005 WL). This proposed limit provides a basis for assessing the
effectiveness of reclamation in minimizing indoor exposures to radon progeny.
For any homes that are constructed on reclaimed lands at the South Fort Meade
site, the predicted indoor radon progeny concentrations could range from a low
of 0.0068 WL over overburden fill areas (477 acres) to 0.0172 WL over the
8,194 acres of reclaimed clay settling areas. The predicted radon progeny
concentrations for homes over the 1,489 acres of clay settling areas with sand
cap would be 0.0121 WL, and homes over the sand tailings fill areas with over-
burden cap (5,034 acres) would be 0.0082 WL. By way of comparison, slab-on-
grade structures in Polk County over undisturbed lands have WL's ranging from
0.001 to 0.010, with a geometric mean of 0.003. Residences on the reclaimed
overburden fill areas (477 acres) or sand tailings capped with overburden
areas (5,034 acres) would have predicted indoor radon progeny marginally below
the EPA recommended 0.009 WL limit described above. If residences were
planned in other reclaimed areas, they would have to be designed so as to
prevent the accumulation of radon progeny to levels above the recommended .009
WL limit.
There is also an interim EPA recommendation (41CFR123, June 24, 1976) to limit
gamma exposure levels at new structure sites on Florida phosphate lands to 10
uR/h. Given the current degree of uncertainty as to what constitutes a "no-
effects" level of radiation on reclaimed phosphate lands, it is informative to
compare the various reclamation alternatives considering these proposed cri-
teria. As shown in Table 3.3-3, the predicted gamma radiation levels for all
3-55
-------
land types except above-grade clay settling areas (44 uR/h) and below-grade
clay settling areas covered with water (4 to 85 uR/h depending upon the amount
of attenuation by water) meet the interim EPA recommendation for a gamma ex-
posure level limit of 10 uR/h. The above-grade clay settling areas, consti-
tuting 6,681 acres or about 44 percent of the reclaimed lands, are consider-
ably above the interim recommended gamma level and thus, no structures could
be constructed thereon without use of some type of mitigating measures to
lower the exposure levels. For the 1,513 acres of below-grade clay settling
areas, the water could be expected to attenuate much of the gamma radiation,
although if the area were to completely dry out, the gamma radiation could
approach the level of the above-grade clay settling area. The 1,489 acres of
above-grade clay capped with sand tailings would have an estimated gamma
radiation level of 9 uR/hr, marginally below the interim EPA recommendation of
10 uR/hr. Overburden fill areas, comprising 477 acres, and 5,034 acres of
sand tailings capped with overburden would be well below the 10 uR/hr limit.
Radionuclide uptake by crops and subsequent passage through the food chain is
another area of concern on reclaimed lands. Radionuclide uptake in crops ap-
parently is a function of soil characteristics, crop type, calcium concen-
tration and soil radium-226 concentration. Mobil's reclamation plan calls for
the return of much of the site to agricultural usage. There is no evidence
that agricultural development of the reclaimed mine site would pose a signifi-
cant radiological hazard through soil-to-crop-to-man food chain uptake. How-
ever, little is known about the behavior of Ra-226 uptake from this type of
soil. It should be noted that current fertilizer products may contain Ra-226
up to 32 pCi/g. Thus, direct application of fertilizer products to crops may
be of more concern than the direct radionuclide uptake from reclaimed soils.
Surface soil radium-226 concentrations at 16 locations on the South Fort Meade
site ranged from 0.2 to 1.1 pCi/g with an average of 0.4 pCi/g. The waste
disposal and reclamation process will redistribute radioactive materials in
the soil profile, resulting in increased surface soil radium-226 concen-
trations. As shown in Table 3.3-3, surface soil radium-226 levels for re-
claimed lands are expected to range from 1 pCi/g for the 477 acres of over-
burden fill areas to 22 pCi/g for the 6,681 acres of above-grade clay settling
3-56
-------
areas and 1,513 acres of below-grade clay settling areas. Estimated
radium-226 concentrations for the 5,034 acres of sand tailings capped with
overburden and 1,489 acres of above-grade clay capped with sand tailings are 3
pCi/g.
Radon flux from waste disposal materials is another concern for reclaimed land-
forms. The radon flux indicates the potential hazard associated with construc-
tion of slab-on-grade residential and public structures on reclaimed lands,
and correlates to the indoor radon progeny measured as WL. Radon flux measure-
ments on unaltered lands in Polk County range from <0.1 to 1.1 pCi/m2/sec with
an average of 0.2 pCi/m2/sec (Roessler, 1978). The radon fluxes shown in
Table 3.3-3 for each reclaimed landform were calculated from a bi-layer dif-
fusion model, using parameters taken from the data of Roessler et al. (1978)
for similar media. It is estimated that the process of land reclamation would
increase the radon flux of the unaltered land to a range of 0.59 pCi/m2/sec
(for the 477 acres of overburden fill) to 4.38 pCi/m2/sec (for the 6,681 acres
of above-grade clay settling area and 1,513 acres of below-grade clay settling
areas). Radon flux from the 5,034 acres of sand tailings capped with over-
burden is projected to be 0.87 pCi/m /sec, and 2.05 pCi/m2/sec from the 1,489
acres of above-grade clay capped with sand tailings.
Decant water from the clay settling ponds would be recycled through the water
recirculation system. The typical concentration of radium-226 in water re-
leased from clay settling areas is 1 to 2 pCi/1, which is less than the allow-
able concentration of 5 pCi/1 in drinking water. Release of this water should
have a minimal effect on the radiological characteristics of surface water
supplies (EPA, 1978).
Groundwater radiation levels are not expected to increase as a result of rec-
lamation. Groundwater in the Surficial Aquifer would be in contact with
basically the same material present before mining. Moreover, some of the
radioactivity initially present would remain with the product, reducing the
total amount of radionuclides left in the soil.
3-57
-------
Surface water quality is not expected to be degraded by land reclamation.
Radium-226 is not very soluble (2xlO~6 g/100 ml as radium sulfate) and is
found in low concentrations (0.67 pCi/1) even in clay pond effluents, which
are in contact with clays containing relatively high levels of radium-226
(22.4 pCi/g). Since waste clay settling areas would have the highest radium-
226 levels of all reclaimed lands, radiological effects of reclamation on sur-
face water are expected to be minimal.
Sand/Clay Cap Plan: The sand/clay cap reclamation plan would result in five
basic landforms: above-grade clay settling areas with sand/clay mix (4:1) cap
(7,580 acres), sand tailings fill areas with overburden cap (5,079 acres),
below-grade clay settling areas with partial overburden cap (1,513 acres),
above-grade clay settling areas with overburden cap (590 acres) and overburden
fill areas (432 acres). Under the sand/clay cap alternative, the predicted ex-
posure levels for radon progeny would range from a low of 0.0068 WL for the
432 acres of overburden fill area to 0.0172 WL for the 1,513 acres of below-
grade clay settling areas (Table 3.3-4). However, it is extremely unlikely
that residential structures would be built in the below-grade clay settling
areas because they would be reclaimed as wetlands. The 7,580 acres of clay
settling areas capped with a 4:1 sand/clay mix would produce an estimated
radon progeny level of 0.0126 WL, and structures built on such lands would
require measures to reduce the indoor radon progeny to below the recommended
0.009 WL limit. A total of 5,511 acres, comprised of 5,079 acres of sand
tailings capped with overburden and 432 acres of overburden fill, would meet
the recommended 0.009 WL limit with 0.0082 WL and 0.0068 WL, respectively
(although marginally in the case of the sand tailings areas capped with
overburden). Approximately the same amount of acreage is also below the
recommended 0.009 WL limit for the conventional plan.
The sand/clay cap plan would result in a total of 9,683 acres of reclaimed
land potentially exceeding the interim gamma radiation exposure level of 10
uR/hr, or a total of 1,479 more acres than occurs with the conventional plan.
The area of sand tailings capped with overburden, with an estimated gamma
radiation of 5 uR/hr, would increase slightly from 5,034 acres under the
3-58
-------
TABLE 3.3-4
ESTIMATED RADIOLOGICAL CHARACTERISTICS FOR RECLAIMED LANDS
(Sand/Clay Cap Plan)
CO
I
01
Land form
Sand Tdi 1 inys Capped
with Overburden
Clay Capped with Over-
burden (Above-Urade)
Overburden Fill
ttelow-Grade Clay Settling
Areas (Wetland)
Clay Capped with Sand/Clay
Mix. (4:1)
Acreaye
5,0/y
byo
432
I,bl3
7,bŤ0
Gaimid Radiation
(uK/hr)
b (4-7)
38 (22-72)
b (4-7)
(4-85)*
10 (M~Z6)
Soil Kadium-226
(pCi/y)
3 (2-4)
iy (10-38)
1 (
-------
conventional plan to 5,079 acres. The overburden fill area (5 uR/hr) would
decrease slightly from 477 to 432 acres. The significant difference between
the two cases is that the 7,580 acres of clay settling areas capped with a 4:1
sand/clay mix would have an estimated gamma radiation level of 18 uR/hr
(ranging from 14 to 25 uR/hr) as compared to the 6,681 acres of uncapped clay
fill in the conventional case having an estimated gamma radiation level of 44
uR/hr (ranging from 25 to 85 uR/hr). The 1,513 acres of below-grade clay
settling areas would have a projected gamma radiation level ranging from 4 to
85 uR/hr depending on the amount of attenuation by water. Higher water levels
in the wetland area would tend to reduce the gamma radiation levels. Only the
590 acres of clay areas capped with overburden with a projected gamma exposure
rate of 38 uR/hr approach the 44 uR/hr exposure rate for above-grade clay
settling areas for the conventional plan. Thus, the sand/clay cap alternative
would reduce gamma exposure as compared to the conventional case.
Soil radium-226 concentrations (Table 3.3-4) are expected to range from 1
pCi/g for the 432 acres of overburden fill to 22 pCi/g for the 1,513 acres of
below-grade clay settling areas. A total of 5,079 acres of sand tailings
capped with overburden would have an estimated soil radium-226 concentration
of 3 pCi/g. The major difference between this alternative and the conven-
tional plan is that the large area of clay capped with a 4:1 sand/clay mix
(7,580 acres) would have an estimated soil radium-226 concentration of 10
pCi/g, whereas the conventional plan would have 6,681 acres of above-grade
clay settling areas at 22 pCi/g. Since surface radium-226 concentrations are
generally reduced, radionuclide uptake by crops would probably be less for the
clay settling areas covered with sand/clay mix (10 pCi/g) than the clay set-
tling areas under the conventional plan (22 pCi/g).
The predicted radon fluxes are less for the sand/clay cap plan than for the
conventional plan, with a range of 0.59 PCi/m2/sec for the 432 acres of over-
burden fill to 4.38 pCi/m2/sec for the 1,513 acres of below-grade clay set-
tling, as shown in Table 3.3-4. The 5,079 acres of sand tailings capped with
overburden and the 590 acres of above-grade clay settling areas would have
projected radon fluxes of 0.87 and 3.67 pC1/m2/sec, respectively. The largest
reclaimed landform, the clay settling areas capped with a 4:1 sand clay mix,
3-60
-------
2
would have an estimated radon flux of 2.25 pCi/m /sec, significantly less than
2
the 4.38 pCi/m /sec projected for the 6,681 acres of above-grade clay settling
areas under the conventional plan.
The radiological effects of the sand/clay cap plan on surface water and ground-
water would be, for all practical purposes, identical to the conventional clay
settling plan, and are expected to be minimal.
Sand/Clay Mix Plan: The sand/clay mix plan would result in six basic re-
claimed landforms: sand/clay mix (3,512 acres), clay settling areas with
sand/clay mix cap (3,185 acres), sand tailings fill areas with overburden cap
(3,020 acres), below-grade clay settling areas (2,095 acres), overburden fill
areas (1,740 acres) and uncapped above-grade clay settling areas (1,642
acres). If the sand/clay mix plan were adopted, the exposure levels for radon
progeny as measured by WL would generally be lower than the conventional clay
settling plan but above the sand/clay cap plan. As shown in Table 3.3-5, a
total of 3,737 acres would have the highest estimated indoor radon progeny
level of 0.0172 WL, including 1,642 acres of above-grade clay settling areas
and 2,095 acres of below-grade clay settling areas. The below-grade settling
areas would be wetlands and since these lands will be subject to frequent
inundations, it is unlikely that they will be utilized for the construction of
residential or public buildings. Other significant reclaimed landforms which
will be above the 0.009 WL limit include 3,512 acres of 2:1 sand/clay mix at
0.00112 WL and 3,185 acres of clay capped with the sand/clay mix at 0.0125 WL.
A total of 4,760 acres would be below the interim recommended limit of 0.009
WL: 3,020 acres of sand tailings capped with overburden at 0.0082 WL and 1,740
acres of overburden fill at 0.0068 WL. This acreage is less than with either
the conventional clay settling or sand/clay cap alternatives.
The sand/clay mix plan results in a total of 10,434 acres of reclaimed lands
which would exceed the interim gamma exposure limit of 10 uR/h. Thus, sub-
stantially more acreage exceeds this limit under the sand/clay mix plan than
occurs with the proposed action (6,681 acres). It must be recognized, how-
ever, that the area of land with the highest gamma radiation levels (44 uR/h)
is 6,681 acres in the conventional plan and only 1,642 acres (above-grade clay
3-61
-------
TABLE 3.3-5
ESTIMATED RADIOLOGICAL CHARACTERISTICS FOR RECLAIMED LANDS
(Sand/Clay Mix Plan)
en
ro
Land form Acreage
Sand Tailings Capped 3,020
with Overburden
Above-Grade Clay l,i>42
Settling Areas
Sand/Clay Nix (2:1) 3,bl2
Overburden Fill 1,740
Clay Capped with 3.18b
Sand/Clay Mix (2:1)
Below-Grade Clay Settling 2,09b
Areas (Wetland)
Gamiia Kadi at ion
(uK/hr)
b (4-7)
44 (25-85)
22 (16-34)
b (4-7)
22 (16-34)
(4-85)*
Soil Radium- 226
3 (2-4)
22 (12-45)
10 (7-17)
1 (
-------
settling areas) for the sand/clay mix reclamation approach. Potential radia-
tion exposure to the general public is thus lower for the sand/clay mix plan
than for the conventional reclamation plan. The projected gamma radiation on
3,512 acres of 2:1 sand/clay mix (22 uR/hr) and 3,185 acres of clay capped
with the sand/clay mix (25 uR/hr) is substantially greater than the interim
exposure limit of 10 uR/hr. However, 1,740 acres of overburden fill (5 uR/hr)
and 3,020 acres of sand tailings capped with overburden (5 uR/hr) are well
within the recommended limit. The 2,095 acres of below-grade clay settling
areas have an estimated gamma radiation level with a range of 4 to 85 uR/hr,
depending on the depth of water present to attenuate gamma radiation.
With the sand/clay mix plan, a mixture of two-parts sand to one-part clay
would be used to reduce the amount of conventional clay settling areas. As
shown in Table 3.3-5, the 3,512 acres of sand/clay mix (10 pCi/g) and 3,185
acres of clay capped with sand/clay mix (12 pCi/g) would have predicted
radium-226 concentrations significantly less than the 22 pC1/g for conven-
tional clay settling areas. With the sand/clay mix alternative, the area used
for conventional clay settling would be reduced to 1,642 acres from 6,681
acres under the proposed action. The below-grade clay settling areas would
have an estimated soil radium-226 concentration of 22 pCi/g, and would be in-
creased from 1,513 acres under the conventional plan to 2,095 acres. The
lowest soil radium-226 concentrations under the sand/clay mix alternative
would be an estimated 1 pCi/g for the 1,740 acres of overburden fill and 3
pCi/g for the 3,020 acres of sand tailings capped with overburden.
Agricultural use of reclaimed lands under the sand/clay mix plan would result
in a lower potential for radium-226 uptake by crops since the uncapped clay
settling areas with the highest level of radium-226 (44 pCi/g) total far fewer
acres than in the conventional plan (1,642 acres versus 6,681 acres).
Overall, the estimated radon fluxes would be less for the sand/clay mix case
than for the conventional case. The highest estimated radon flux, 4.38
pCi/m2/sec, would occur on 1,642 acres of above-grade clay settling areas and
2,095 acres of below-grade clay settling areas. Much of the 6,681 acres of
above-grade clay settling areas (4.38 pCi/m2/sec) in the conventional plan
3-63
-------
o
would be replaced with 3,512 acres of sand/clay mix (1.71 pCi/tn /sec) or the
3,185 acres of clay capped with sand/clay mix (2.20 pCi/m2/sec). Although the
area of overburden fill (0.59 pCi/m2/sec) would be increased from 477 acres to
1,740 acres from the conventional plan, the amount of sand tailings areas
y '
capped with overburden (0.87 pCi/nr/sec) would be decreased substantially,
from 5,079 to 3,020 acres.
Overburden Mix Plan: Five land types would result from waste disposal and
reclamation with this alternative: sand tailings capped with overburden
(3,020 acres), overburden fill areas (1,740 acres), below-grade clay settling
areas (2,095 acres), above-grade clay settling areas with sand/clay mix (2:1)
cap (2,847 acres), and sand/clay mix (2:1) lands (5,492 acres).
Based on a maximum indoor radon progeny of 0.009 WL, a total of 4,760 acres of
reclaimed land under this plan would be suitable for the construction of resi-
dences and public buildings (Table 3.3-6). This acreage includes 3,020 acres
of sand tailings capped with overburden (0.0082 WL) and 1,740 acres of over-
burden fill (0.0068 WL). On the 5,492 acres of overburden sand/clay mix areas
and on the 2847 acres of capped clay settling areas, the projected indoor
radon progeny are 0.0126 WL, and 0.0125 WL, respectively, which means that
mitigation measures would be required to allow construction. From this stand-
point, the overburden mix case offers no advantage over the proposed action.
The below-grade clay settling area of 2,095 acres has an estimated radon
progeny of 0.0172 WL, which is high. It is unlikely that construction will be
desirable in an area frequently inundated with water.
Under the overburden mix alternative, a total of 4,760 acres are expected to
exhibit gamma radiation levels well below the 10 uR/hr interim limit. This
area, comprised of 3,020 acres of sand tailings capped with overburden and
1,740 acres of overburden fill (both with an estimated gamma radiation level
of 5 uR/hr), is smaller than the conventional case, where 7,000 acres are
below the interim limit. The 2,095 acres of below-grade clay settling areas
(4 to 85 uR/hr) could be expected to meet the interim limit when water levels
sufficient to attenuate the gamma radiation are present. At times when water
levels are low, this limit could be exceeded. The 5,492 acres of overburden
3-64
-------
TABLE 3.3-6_
ESTIMATED RADIOLOGICAL CHARACTERISTICS FOR RECLAIMED LANDS
(Overburden Mix Plan)
oo
i
o>
01
Land form Acreage
Sand Tailings Capped 3,020
with Overburden
Overburden Fill 1,740
Below-Grade Clay Settling 2,09b
Areas (Wetlands)
Overburden Sand/Clay 5,192
Mix (2:1)
Clay Settling Areas 2,847
with Sand/Clay
Mix (2:1) Cap
tiamna Radiation
(uR/hr)
5 (4-7)
5 ( 4-7)
(4-85)*
18 (13-32)
22 (16-34)
Soil Kadi urn- 226
(pCi/g)
3 (2-4)
1 Ťl-2)
22 (12-45)
8 (5-16)
12 (8-22)
Radon Flux
(pCi/m^/sec)
0.873
0.59
4.38
2.00
2.20
Working
Level
(ML)
0.0082
0.0068
0.0172
0.0126
0.0125
Range is shown in ( ).
Calculation source for radon flux and working level: "National Radiation Exposure Assessment: Radio-
activity of Lands and Associated Structures," Final Report Volume 2, February 1978, C.E. Roessler, J.A.
Wethington, Jr., and W.E. Bolch.
Calculation source for gamma radiation: "National Council on Radiation Protection and Measurements"
Natural Background in the United States, Report No. 45, November 1975.
Values for Radium-226 represent the top two feet of material. Calculated from soil characterization.
* The below-grade clay settling areas would be reclaimed as wetlands. The gamma radiation level would vary
depending on the depth of water over the soil surface.
-------
sand/clay mix would have an estimated level of 18 uR/hr, well above the in-
terim limit. The 2,847 acres of clay settling areas with sand/clay mix cap
would have an estimated level of 22 uR/hr, also well above the interim limit.
The major difference between this alternative and the conventional clay
settling case is the absence of above-grade conventional clay settling areas
with their associated higher radiation levels. Thus, no areas under this plan
would have gamma radiation levels as high as the 44 uR/hr of conventional clay
settling areas, with the possible exception of the below-grade clay settling
areas if they were to dry out.
With respect to agricultural use, the overburden mix case results in signif-
icantly lower soil radium-226 levels than conventional reclamation, reducing
the potential for crop uptake of radium-226. As discussed earlier, however,
studies by Mobil showed no significant radium-226 uptake on reclaimed lands
with relatively high soil concentrations of this radionuclide. Soil radium-
226 concentrations would range from an estimated 1 pCi/g for the 1,740 acres
of overburden fill to 22 pCi/g for the 2,095 acres of below-grade clay set-
tling areas. The 3,020 acres of sand tailings capped with overburden would
have an estimated radium-226 value of 3 pCi/g. The overall radium-226 levels
in the reclaimed lands for this case would generally be lower than for the
proposed action.
On the average, radon fluxes would be lower for the overburden mix plan than
the conventional plan. The 3,020 acres of sand tailings capped with over-
burden (0.87 pCi/m2/sec), the 1,740 acres of overburden fill (0.59 pCi/m /
sec), and the 2,095 acres of below-grade clay settling areas (4.38 pCi/m /sec)
are comparable to the conventional plan. However, the 6,681 acres of above-
grade clay settling areas (4.38 pCi/m2/sec) and the 1,489 acres of above-grade
clay capped with sand tailings (2.05 pCi/m2/sec) have been replaced by the
5,492 acres of overburden sand/clay mix (2.00 pCi/m2/sec) and 2,847 acres of
clay settling areas with sand/clay mix cap (2.2 pCi/m2/sec), an improvement
over the conventional plan.
The radiological effects of the overburden mix case on groundwater and surface
water are, for all practical purposes, identical to the proposed action.
3-66
-------
3.3.2.2.4 Product Transport Alternatives
Railroad (Mobil's Proposed Action): Radiological impacts due to product trans-
port should be minor. For transport by railroad, dust generation and spillage
would be transient effects. Accidental spillage could occur but would be
cleaned up and would not pose a significant radiological impact.
Truck: The use of trucks for transport would not have radiological effects
significantly different from the use of railroad cars.
3.4 GROUNDWATER
3.4.1 THE AFFECTED ENVIRONMENT
3.4.1.1 Groundwater System
The groundwater system in southern Polk County consists of a water table aqui-
fer and an artesian (confined) aquifer system. The water table aquifer is
commonly referred to as the Shallow or Surficial Aquifer. The artesian aqui-
fer system, or the Floridan Aquifer, is divided into two distinctive units
commonly referred to as the Upper Floridan and Lower Floridan Aquifers. The
Floridan Aquifer is one of the most productive aquifers in the United States,
and is the principal source of potable water in the region. In the area of
the proposed South Fort Meade Mine site, groundwater is used for irrigation,
municipal, industrial and domestic supplies. Throughout the region, the arte-
sian-surface elevation varies approximately five to fifteen feet during the
year. These fluctuations are due to seasonal groundwater demands for irri-
gation, variations in aquifer recharge as a result of rainfall patterns and
changes in barometric pressure.
Studies of the groundwater system were undertaken at the South Fort Meade site
to identify the geologic sections and yield characteristics of the formations
(Figure 3.4-A). At the site, the Surficial Aquifer was found to extend from
near the surface to an average depth of 25 feet. Clayey units of the Hawthorn
Formation and the silty and clayey portions of the undifferentiated elastics
at the base of the surficial deposits separate the Surficial Aquifer from the
Upper Floridan Aquifer. The Upper Floridan Aquifer was determined to consist
3-67
-------
FIGURE 3.4-A
9
HYDROGEOLOGIC CROSS SECTION
OF THE PROPOSED MINE SITE
STRATIQRAPHIC
UNIT
UNOIFFEHENTIATEO
CLA3T1C3
HAWTHORN FORMATION
TAMPA
FORMATION
LIMESTONE UNIT
SAND * CLAY
UNIT
SUWANEE LIMESTONE
OCALA QROUP
AVON PARK LIMESTONE
CRYSTAL RIVER
FORMATION
WILU8TON
FORMATION
INQU8
FORMATION
LIMESTONE
UNIT
DOLOMITE UNIT
LIMESTONE UNIT
LAKE CITY LIMESTONE
-X~^-\_^ V>
OUMCE: STUDY DATA
APPROXIMATE
THICKNESS
IN FEET
45
80
105
70
90
340
275
160
240
^^-^-
AVERAGE DEPTH
TO TOP OF UNIT
IN FEET
-^~^^-^~^^^_
AQUIFER &
CONFINING
UNITS
SHALLOW AQUIFER
CONFINING UNIT
UPPER FLORIDA*
CONFINING UNIT
LOWER FLORIOAN
CONFWMO UNIT
/ s>~_
WATER-
PRODUCING
PROPERTIES
POOR TO MODERATE
POOR
POOR TO MODERATE
POOR
GOOD TO EXCELLENT
POOR
-------
of about 145 feet of dolomitic limestone inter!ayered with phosphatic sands
and sandy clay. A sand and clay section of the Tampa Formation establishes a
confining unit between the Upper and Lower Floridan Aquifers, although there
is evidence of hydraulic communication between the two aquifers. The Lower
Floridan Aquifer consists of permeable limestone and extends from 300 to 1,405
feet below the surface. The base of the Lower Floridan Aquifer is confined by
the upper units of the Lake City Limestone, in which the pore spaces are fill-
ed or partially filled with evaporites. (Also see Section 3,2, Geology and
Soils.)
3.4.1.2 Groundwater Quantity
3.4.1.2.1 Surficial Aquifer
The Surficial Aquifer is a source of small quantities of groundwater used for
irrigation and domestic supply in the vicinity of the proposed mine site. The
water level in the Surficial Aquifer remains approximately 50 feet or more
above the piezometric surface of the Upper Floridan Aquifer (Figure 3.4-B).
Under natural conditions, water from the Surficial Aquifer slowly recharges
the underlying Upper Floridan Aquifer, and this water in turn is transmitted
to the Lower Floridan Aquifer.
The Surficial Aquifer at the site was further defined during the study period
(January to August, 1980) by data from 10 wells summarized as follows:
Level of water table
Average depth below surface - 10.5 ft
Range of depth below surface - 2 ft to 37 ft
Average fluctuation per well - 4.3 ft
-4 3
Leakance - 1 x 10 gpd/ft
Transmissivity - 11 to 43 gpd/ft
Permeability - 0.96 gpd/ft2 or
Yield - small, less than 1 gpm
Permeability - 0.96 gpd/ft2 or 4.5 x 10~5cm/sec
3.4.1.2.2 Upper Floridan Aquifer
The Upper Floridan Aquifer is artesian, with a piezometric surface about 10
feet higher than that of the Lower Floridan Aquifer (Figure 3.4-B). It is
utilized for local domestic and small irrigation supplies and commonly yields
3-69
-------
GRAPH OF WATER LEVEL FLUCTUATIONS
IN WELLS SA-5, UF-5 AND LF-5, JANUARY TO AUGUST 1980
131-
129- -
i 127
co
UJ
177
(_- 76-
UJ
UJ
U. 73
2
to 71
O
/.
Shallow Aquifer
60- -
UJ
j
UJ
UJ
83
61. .
59 -
'jt
-.>
M
5
\
\
>N
5 15 26
JANUARY
\
J L
5 16 26
FEBRUARY
5 15 26
MARCH
I I
J L
6 16 26
APR*.
Upper Floridan Aquifer
WELL 3A-6
WELL UF-5
. WELL LF-6
Lower Floridan Aquifer
,.~,,-"y
JI 1L
5 15 25
MAY
i i i
15 26
JUNE
J L.
5 16 25
JULY
6 15 25
AUGUST
MONTH (198O)
LEGEND
Recording
Inslrument*
Malfunctioned
SOURCE: Study Data
'
I
-------
from a few tens of gallons per minute to several hundreds of gallons per min-
ute. The low transmissivity of the aquifer makes it extremely difficult to
develop large quantities of water.
A summary of the Upper Floridan Aquifer characteristics on the Mobil site
defined during the study period are presented below:
Water level (piezometric surface)
Average depth below surface - 64.5 ft
Range of depth below surface - 33.7 ft to 97.6 ft
Average fluctuation - 12 ft
Average aquifer thickness - 145 ft
Average Aquifer Depth - 85 ft to 230 ft below surface
Transmissivity - 10,000 gpd/ft
Leakance - 2 x 10"3 gpd/ft3 (Upper Floridan to Lower Floridan)
Permeability - 69 gpd/ft2 or 3.25 x 10" cm/sec
Yield - 20 to 200 gpm
3.4.1.2.3 Lower Floridan Aquifer
The Lower Floridan Aquifer, also artesian, is the source of most large,
potable groundwater withdrawals in Polk County, Florida. Wells penetrating
this aquifer are commonly capable of producing several million gallons per
day. At the site, water levels in the Lower Floridan Aquifer fluctuate about
12 feet from the dry season to the wet season (Figure 3.4-B). These fluc-
tuations are the result of natural phenomena such as baseflow support to
streams, leakage into the Upper Floridan Aquifer, barometric pressures, evapo-
transpiration and seasonal rainfall, as well as pumpage from the groundwater
system. Industrial pumping remains relatively stable throughout the course of
a year, whereas withdrawals for irrigation may vary from season to season and
even from year to year (EPA, 1978).
Pumping tests conducted at the proposed mine site indicated that large quanti-
ties of water can be withdrawn from the Lower Floridan Aquifer. The aquifer's
hydrologic properties of transmissivity, storativity and leakance, as deter-
mined by the study, compare favorably with those determined in regional
studies conducted by the U.S. Geological Survey (Wilson, 1980).
3-71
-------
Characteristics of the Lower Fieri dan Aquifer defined during the study period
are summarized below:
Water level (piezometric surface)
Average depth below surface - 71 ft
Range of depth below surface - 52 ft to 84 ft
Average fluctuation - 12 ft
Average Aquifer Thickness - 1,105 ft
Average Aquifer Depth - 300 ft to 1,405 ft below surface
Transmissivity - 1,300,000 gpd/ft2
Leakance - very low permeability (base of Lower Floridan)
Permeability - 1,176 gpd/ft2 or 5.55 x 10"2 cm/sec
Yield - up to several mgd per well
3.4.1.3 Groundwater Quality
On a regional basis, water from the Floridan Aquifer is of suitable quality to
be utilized for potable water supplies, for industrial processing requirements
and for agricultural irrigation. Regional groundwater quality is relatively
consistent in the Floridan Aquifer except for certain areas along the Gulf of
Mexico where saltwater intrusion has been experienced, and beneath the potable
zones of the Floridan Aquifer where incomplete flushing of the natural system
or the presence of certain minerals has left highly mineralized water.
3.4.1.3.1 Surficial Aquifer
The quality of groundwater in the Surficial Aquifer varies considerably in the
region due to local lithologic conditions. Water in the Surficial Aquifer at
the South Fort Meade site is generally high in iron concentration (0.1 to 6.3
mg/1) and has a pH value less than seven. Data from nine test wells sampled
on the site are presented in Table 3.4-1 along with EPA drinking water stan-
dards and Florida Class B standards.
3.4.1.3.2 Upper Floridan Aquifer
The chemical composition of the water from the Upper Floridan Aquifer at the
proposed mine site (Table 3.4-1) is similar to that from wells penetrating the
3-72
-------
TABLE 3.4-1
CHEMICAL ANALYSIS OF WATER FROM THE SHALLOW AQUIFER1
to
I
CO
Florida
CroundMter'
Clan 1-8
Constltvtnt Standards
Conductivity
(taťlť)/oť)3
PH3
Temperature
<°c)3
Acidity (CŤC03)
Total Alkalinity
(CaCOj)
Total Solids (CaCOj)
Total Dissolved Solids
Color (PCU)
fluoride (F) 1.4
Total Phosphorus
Ortho- Phosphate (PQ4)
Organic Nitrogen
Aamnla (HN])
Nitrate (N03) 10.0
Nitrite (N02)
Silica (S102)
Sulfate
Totil Organic Carbon
(-9C/1)
Alumlnun (AL)
Arsenic (As) 0.05
8ar1un (Ba) 1.0
Cadmium (Cd) 0.01
Calcium (C.4)
Chromium (Cr) 0.05
Copper (Cu)
Iron (Fe)
Lead (P6) 0.05
Hagneslu* (Mg).
Hercury (Hg) 0.002
Nickel (It)
PotŤS5tuť (K)
Selenium (Se) 0.01
Silver (Ag) 0.05
Sodium (Na)
Strontium (Sr)
Chloride (Cl)
Pesticide Scan
Oil and Grease
Total Hardness
(C.C03)
Gross Alpha PICo
Curries/I 15.01
Radium 226
All constituents are In mg/1 ex
1 Well XA1 MS not SMinled due
1 Drinking
Kat.r -
Standard'
6.5-8.5
-
-
-
-
500 R
15 R
1.4-2.8 M
-
-
10.0 H
-
250 R
0.05 K
1.0 N
0.01 H
200 R
0.05 H
1.0 R
0.3 R
0.05 H
125 R
0.002 H
-
-
0.01 H
0.05 H
200 R
250 R
-
-
-
15.0
-
cept pH and those n<
to dent.h nf water.
SA-Z
9-26-80
56
5. SO
27
8
12
1470
-
1000
0.12
13.4
0.38
0.56
0.28
<0.02
0.01
10.7
(1.0
12.0
16.7
<0.05
0.2
0.01
4.41
<0.04
(0.03
J.45
0.2
8.83
(0.001
<0.06
0.878
<0.01
(0.03
63.1
0.578
-
HD5
-
-
26.3 *_ 7.3
9.8 * 0.4
Ited.
SA-3
9-26-80
225
5.95
29
7
22
191
150
0.46
0.36
0.20
0.15
0.20
0.13
0.02
15.0
35.4
6.5
3.90
<0.05
CO.]
<0.01
9.85
<0.04
<0.03
1.58
(0.01
5.04
(0.001
<0.06
0.890
<0.01
<0.03
38.0
0.58
13.0
ND
-
<5.4
1.1 ť 0.1
SA-4
Ť-2*-Ť0
IN
t.ra
29
3
75
118
-
5
0.28
0.33
0.27
0.04
0.26
(0.02
<0.01
19.7
2.5
1.0
<0.40
(0.05
<0.l
<0.01
10.9
<0.04
(0.03
0.11
0.1
9.93
<0.001
<0.06
0.728
(0.01
(0.03
23.6
(0.01
m
-
(0.2
68
<ť.4
-(0.4
SA-t.
9-25-80
135
5. SO
27
14
31
104
-
30
0.50
1.10
1.02
0.77
0.14
(0.02
(0.01
16.1
1,9
1.3
0.88
(0.05
<0.01
(0.01
9.60
(0.04
(0.03
Z.04
(0.01
3.47
<0.006
(0.06
0.372
(0.01
(0.03
18.4
(0.10
NO
-
-
SA-7
9-26-80
60
5.t5
26
7
10
148
200
0.30
1.04
0.34
0.49
(0.10
0.4
(0.01
8.2
1.0
2.3
7.69
(0.05
(0.01
(0.01
4.73
(0.04
(0.03
1.61
0.1
1.66
(0.001
(0.06
0.388
(0.01
(0.03
24.5
0.33
-
HD
(4.1
-
SA-9
9-zs-ao
90
6.45
26
6
25
716
-
500
0.43
1.33
0.91
0.69
(0.10
0.25
<0.01
9.6
6.6
6.5
2.5
(0.05
0.3
0.01
10.1
0.06
(0.03
4.59
<0.1
2.76
(0.001
(0.06
3.54
<0.01
(0.03
21.5
1.67
-
NO
-
97 + 16.7
14.6 + 0.5
SA-10
t-n-n
170
i.Ť
28
7
39
120
-
15
0.53
0.86
0.59
0.12
0.21
2.1
(0.01
9.1
VI. 5
2.7
1.2U
(0.05
(0.01
0.01
15.7
<0.04
(0.03
0.04
<0.01
4.81
(0.001
(0.06
0.995
<0.01
(0.03
14.8
0.31
ND
<0.9
SA-5
9-?5-Ť0
225
6.15
29
11
67
176
-
200
0.28
0.15
0.03
0.16
0.48
(0.02
(0.01
7.8
9.8
7.6
1.20
(0.05
(0.01
U.01
13.1
<0.04
<0.03
6.28
<0.01
5.35
(0.001
(O.U6
1.61
(0.01
(0.03
36.7
0.54
ND
4.8 + 4.6
1.1 i 0.1
Environmental Protection Agency Primary and Secondary standards (Partial List); M (Ibndatory) II (KecoxwuM).
iťupt 2-28-80 saml>.
4 lorn detected.
Includes all groundMter with fotŤl dissolved solids IMS tn*n lO.flBO iHj/l,i
FŤC Ckiftcr 17.3.
SOURCE: STUDY DATA
-------
same aquifer at the Estech Duette Mine and the CF Industries Hardee County
Mine. The water in the Upper Floridan Aquifer is more mineralized than that
found in the Shallow Aquifer, particularly with respect to constituents de-
rived from the carbonate rock making up the Upper Floridan Aquifer. The
parameters showing higher values are sulfate, calcium, alkalinity, total
hardness and total dissolved solids.
3.4.1.3.3 Lower Floridan Aquifer
Water found in the Lower Floridan Aquifer at the site is also of similar
quality to that found at the Estech Duette Mine, at CF Industries Hardee
County Mine, and at other locations in the region. The upper and middle
sections of the aquifer contain potable water, but below 1,200 feet increased
mineralization is evident. The mineral content increases with depth through
the lower section due to the dissolution of naturally occurring sulfate
minerals known to exist in that section of the aquifer. Table 3.4-1 shows the
results of chemical analysis of the water collected at the end of the 10-day
pumping test of the Lower Floridan Aquifer.
3.4.2 ENVIRONMENTAL CONSEQUENCES OF THE ALTERNATIVES
3.4.2.1 The No Action Alternative
Under the no action alternative groundwater would continue to be used for irri-
gation, municipal, industrial and domestic supplies in the area of the pro-
posed mine. Seasonal changes in water levels of the Surficial, Lower Floridan
and Upper Floridan Aquifers would not be affected. The hydrologic character-
istics of the Surficial Aquifer would not be altered, nor would recharge to
the Floridan Aquifer change. The quality of groundwater in the region is
presently suitable for potable water supplies, industrial processing and
irrigation and would not be changed as a result of the no action alternative.
3.4.2.2 The Action Alternatives Including the Proposed Action
3.4.2.2.1 Mining Method Alternatives
Dragline (Mobil's Proposed Action): The dragline method would require a rela-
tively dry pit for effective mining. To attain this condition, dewatering of
the Surficial Aquifer would be necessary, temporarily lowering water table
levels adjacent to the pit. Based on aquifer properties determined in the
3-74
-------
baseline study, an average Surficial Aquifer thickness of 25 feet, and an
average pit bottom 45 feet below land surface, a drawdown of one foot (using
the Dupuit method described in Todd, 1959) is expected 115 feet from the peri-
meter of the open pit. Perimeter rim ditches identified in Mobil's proposed
action would negate off-site drawdowns in the water table aquifer.
The dewatering for dragline mining would affect the recharge to the Floridan
Aquifer system as a result of lowering the Surficial Aquifer water table in
the vicinity of the mine pit an average of 38 feet. Utilizing the aquifer
properties determined in the baseline study, it is calculated that the natural
recharge over the project site of three inches per year would be reduced by
about 0.1 inch per year as a result of dewatering activities.
Bucket Wheel: The bucket wheel method of mining would require a totally dry
pit, a condition difficult to attain during the rainy summer months. Addi-
tional dewatering beyond that needed for the dragline would be required.
Impacts from the bucket wheel method, other than those associated with de-
watering, would be similar to the dragline mining method.
Dredge: The dredge mining method would require flooding of the mining area.
Groundwater from the Lower Floridan Aquifer would be used to maintain the
necessary water levels in the dredge pit. This increased pumping would serve
to further lower the piezometric level in the Lower Floridan Aquifer. During
overburden removal, the water level in the pit would be maintained and would,
therefore, have no dewatering effect on the Surficial Aquifer. During matrix
removal the water level would be lowered and maintained above the top of the
matrix, temporarily dewatering the upper zones of the Surficial Aquifer in the
immediate vicinity of the dredge basin.
During overburden removal there would be no effect on natural recharge. Dur-
ing ore extraction, however, the reduction in natural recharge for the total
site would be about 0.03 inches per year or one-third of that calculated for
the dragline mining method.
3-75
-------
Mining by dredge would increase turbidity and suspended solids content in the
recirculation system. Because leach zone management could not be practiced
with this mining method, radioactive particles attached to the suspended
solids could result in increased radiation levels in the water recirculation
system.
3.4.2.2.2 Matrix Transfer Alternatives
Pipeline (Mobil's Proposed Action): The matrix would be slurried at the min-
ing area and transferred to the beneficiation plant by pipeline, requiring
approximately 18,750 gpm of slurry transport water and 480 gpm of pump seal
water. The slurry transport water would be recycled water obtained from the
recirculation system. The pump seal water source would be from wells drilled
into the Upper Floridan Aquifer, and withdrawal points for this water would
change as mining progresses. The changes to the piezometric levels would be
temporary, ceasing with the completion of mining.
Conveyor Belt: Transporting the matrix to the beneficiation plant by conveyor
belt would involve placement of the matrix onto the conveyor without the addi-
tion of water. However, recycled water would still be needed for the conveyor
method as washing water once the matrix reaches the beneficiation plant. The
quantity of recycled water required for the conveyor belt method of transport
would be approximately equivalent to the pipeline transfer method. The pump
seal water requirement (480 gpm) would be eliminated because the booster pumps
would not be needed.
Truck: Truck transport of the matrix would eliminate the need for pump seal
water (480 gpm), but as with conveyor belt transport, overall water require-
ments would not be reduced due to the need for matrix processing water.
3.4.2.2.3 Processing Alternatives
Conventional Beneficiation (Mobil's Proposed Action): The conventional bene-
ficiation process would utilize up to 130 mgd of water from the recirculation
system, and 15.7 mgd of flotation process water and makeup water obtained from
the Lower Floridan Aquifer. This groundwater withdrawal would lower the
3-76
-------
piezometric level of the Lower Floridan Aquifer during the 25 years the bene-
ficiation plant is in operation. The values for transmissivity and leakance
determined for the site during the baseline study were 1,300,000 gpd/ft and
0.002 gpd/ft , respectively. Using the more conservative data included in the
application for a Consumptive Use Permit (CUP) to SWFWMD, and the pumping rate
of 15.7 mgd from three production wells, contours of projected drawdown levels
were developed (Figure 3.4-C). The calculated drawdown in the piezometric
surface at the property boundaries would range from a maximum of 4.3 feet to
less than one foot. The change in the piezometric surface of the Lower
Floridan Aquifer would be temporary. At the end of mining activity, the
pumping would cease and the piezometric level should return to premining con-
ditions.
Withdrawals from the artesian groundwater system could potentially cause up-
ward movement of the higher sulfate water located near the bottom of the Lower
Floridan Aquifer. The higher sulfate water occurs naturally in and slightly
above the evaporite zone. During the 10-day pumping test at the site, an
increase in the sulfate concentration of the discharged water was observed.
After seven days, the concentration of sul fates stabilized at about 530mg/l.
Throughout the test the chloride concentration remained essentially constant
at 12.5 mg/1. Any movement of the high sulfate water, as a result of the
continuous groundwater withdrawals, would be noted first in the production
wells at the project site. The monitoring required as part of Mobil's CUP
from SWFWMD would demonstrate if movement of the high sulfate water were
occurring.
Reagents would be added in the flotation process and would be discharged with
the sand tailings and waste clays. The excess water from the waste sand and
clay disposal areas would drain into the recirculation system from which some
seepage into the Surficial Aquifer would occur via the ditches and canals.
The impact on Surficial Aquifer water quality is discussed in Waste Disposal
(Section 3.4.2.2.4).
3-77
-------
LOWER FLORIDAN AQUIFER DRAWDOWN PROJECTION
>
M
Oo
T32S
N
I MILE
T33S
SOURCE: MOBIL
LEGEND
4' WATER -LEVEL DR/WDOWN,
IN FEET, BELOW STATIC
PRODUCTION WELL
PROPOSED PRODUCTION
WELL
OUT PARCELS
Drawdown contours based on a
total pumping rat* of 15.7 MOD
from three walla.
o
I
-------
Dry Separation^ The dry separation method of processing would not utilize the
large quantities of water required by the conventional beneficiation method.
Due to the small amounts of water required for this method of processing, im-
pacts on the artesian system would be negligible. No chemicals would be used
in the beneficiation process; therefore, groundwater quality would not be af-
fected by this alternative.
3.4.2.2.4 Waste Disposal Alternatives
Conventional Clay Settling Case (Mobil's Proposed Action): Mobil proposes to
dispose of the waste sand and clay in conventional clay settling and sand
tailing disposal areas. As the mined areas are filled with waste materials or
as the wastes are stored above natural grade, a new shallow aquifer would be
established. In the clay settling areas (9,683 acres), the elevation of the
water table would be at or above the top of the clays. As the clays compact,
water would be decanted and returned to the recirculation system, lowering the
water table. As the elevation of the fill in the clay settling areas rises
above the level of the surrounding Shallow Aquifer, the water level would
rise in the adjacent water table system.
In the tailings disposal areas (5,034 acres), the sand would permit rapid drain-
age, allowing the water table to re-establish at a level dependent on the hyd-
rologic characteristics of the surrounding materials. Groundwater in the Sur-
ficial Aquifer would have preferential flow in areas of high permeability such
as the sand tailings fill areas. Sand tailings disposal areas, which do not
retain water like waste clay, would have little impact on water levels in the
Surficial Aquifer, tending to maintain levels similar to those found in
natural conditions.
The greatest consumption of water in the mining operation is water that be-
comes entrained with the waste clays and sand. Approximately 11.6 mgd of
water would be entrained in the waste clay disposal areas and 1.7 mgd of water
would be entrained in the sand tailings disposal areas.
3-79
-------
As waste disposal progresses, recharge to the artesian aquifer would decrease
as the number of waste clay areas increases. Using the final average above-
grade clay fill height of 32.8 feet and 9,683 acres of clay settling area, the
calculated recharge to the artesian aquifer from the clay settling areas would
be 0.1 inches/year. This would reduce the weighted average recharge for the
total site from three inches to about 1.6 inches per year.
Water 1n the recirculation system may contain contaminants from contact with
the ore matrix and from the reagents used in the flotation process. Many of
these contaminants would become entrained with the clays or would be biolog-
ically degraded. Seepage from the clay settling areas and the sand tailings
disposal areas would average 2.7 mgd and would result in minor changes of
water quality in the Surficial Aquifer. A comparison of the quality of
Surficial Aquifer water to that of the water quality of projected clay set-
tling area supernatant is presented in Table 3.4-2. The clays in the clay
settling areas should form a natural seal, reducing seepage from these areas.
Sand/Clay Cap Case: The sand/clay cap waste disposal case is similar to the
conventional clay settling disposal case except that a five foot mixture of
sand/clay (4:1) material would be placed on 7,580 acres of clay settling
areas. This method of waste disposal would have impacts on the groundwater
system similar to that of the proposed action.
Sand/Clay Mix Case: The sand/clay mix case would have 3,512 acres of sand/
clay mix areas, 3,185 acres of clay capped with sand/clay mix and 1,642 acres
of clay settling areas. The two to one mixture of sand and clay does not
significantly increase the permeability of the mixture from that of clay.
Seepage from the sand/clay mix waste disposal areas into the Surficial Aquifer
would be increased slightly. The amount of water retained in the waste dis-
posal areas would be reduced when the clays are mixed with sand. For the
sand/clay mix case, this reduction would be approximately half a million
gallons per day relative to the conventional case (from 11.6 mgd to 11.1 mgd).
3-80
-------
TABLE 3.4-2
COMPARISON OF THE WATER QUALITY OF SHALLOW AQUIFER
JiATER TO TYPICAL VALUES IN CLAY SETTLING AREA SUPERNATANT
Constituents
pH, pH units
Specific Conductance,
mhos/cm
Total Dissolved Sol ids
Calcium
Magnesium
Sod i urn
Potassium
Bicarbonate
Sulfate
Chloride
Iron
Silica
Fluoride
Nitrate (NOj
Phosphorus J
Radium-226, pCi/1
b
Surficial
Aquifer
5.5-8.5
181
134
<0.04
4.94
32.6
1.06
_
9.4
13
2.18
11.6
0.72
0.28
1.98
<1-14.6
c
Clay Settling Area
Supernatant
7.8
523
348
57
22
18
1.3
112
144
17
0.119
2.5
2.0
4.7
0.09
0.67
Units are mg/1 unless otherwise noted.
Average of analyses from Shallow Aquifer wells on the South Fort
Meade site, 2/28/80 and 9/25/80.
Lament, et al. 1975. Characterization Studies of Florida Phosphate
Slimes.
3-81
-------
Overburden/Clay Mix Case: The overburden/clay mix disposal case would contain
5,492 acres of sand/clay mix (2:1) areas and 2,847 acres of clay settling
areas capped with sand/clay mix. This waste disposal alternative would have
potential impacts on the groundwater system similar to the sand/clay mix waste
disposal alternative.
3.4.2.2.5 Reclamation Alternatives
Conventional Clay Settling Plan (Mobil's Proposed Action): During mining
operations, the waste products of the beneficiation process (clays and sand
tailings) would be disposed of in mine cuts and above-ground storage areas.
With the completion of mining operations and waste disposal activities, a
shallow groundwater level would be established in these waste materials depen-
dent on the nature of the waste products in conjunction with topography. The
clay materials in clay disposal areas (9,683 acres) would retain water at or
near the top of the clays. In the sand tailings disposal areas (5,034 acres),
the sand would allow water to drain to a level dependent on the hydrologic
characteristics of the sand and adjacent materials. In the proposed reclama-
tion plan, the sand tailings disposal areas would primarily be along existing
streams. This would provide transitional zones between high water levels of
the waste clay settling areas and the streams.
The premining flow of water through the Surficial Aquifer would change as a
result of the formation of clay disposal areas. After reclamation, ground-
water in the Surficial Aquifer that would have moved through the site would be
blocked and diverted by the 9,683 acres of waste clay. This water would be-
come additional base flow to streams near the mine, thereby increasing evapo-
transpiration and raising the head in the water table upgradient of the site
and recharge at that point to the artesian system.
The conventional reclamation plan would reduce recharge to the artesian
aquifer from the South Fort Meade site as a result of the disposal of waste
clays which have a lower permeability than the premining materials. A reduc-
tion in recharge to 0.1 inches/year at the clay storage areas was calculated
using the hydrologic properties from the baseline study and an estimated waste
3-82
-------
clay permeability of 0.0002 gpd/ft2 (Bromwell, 1976). Although the water
level in the Shallow Aquifer would be increased an average of 32.8 feet, a 1.4
inch/year average reduction of the recharge to the artesian aquifer would
still occur over the property (i.e., from 3 to 1.6 inches/year).
Water from the waste disposal areas could potentially enter the Surficial
Aquifer system. The sand tailings and waste clays would contain naturally
occurring contaminants from the phosphate matrix and residual reagents used in
the flotation process. Groundwater withdrawn from the Surficial Aquifer in
reclaimed areas may contain some of these contaminants.
Sand/Clay Cap Plan: The sand/clay cap reclamation plan would have 7,580 acres
of above-grade clay settling areas capped with five feet of sand/clay mix
(4:1) material, 590 acres of above-grade clay settling basins capped with
overburden, 1,513 acres of below-grade clay settling basins, and 5,079 acres
of sand tailings fill areas capped with overburden. The basin sizes and
configurations would be approximately the same as the proposed conventional
plan.
The sand/clay mix material at a 4:1 ratio would have a permeability greater
than the clay alone; therefore, vertical and horizontal water movement in the
five-foot sand/clay cap would be greater than the water movement in the clay.
This would allow a perched water table to be established about five feet below
the surface of the sand/clay cap areas (7,580 acres).
The below-grade clay settling areas (1,513 acres) would be developed as wet-
lands. The water table level in these areas would be near the surface. The
590 acres of above-grade clay settling basins capped with overburden would
have a perched water table in the overburden cap.
The sand tailings fill areas (5,070 acres) would have a high permeability,
allowing rapid drainage and establishment of the Surficial Aquifer water table
at a level dependent upon the adjacent materials. As with the proposed
conventional plan, the sand tailings fill areas would be primarily located
along existing stream channels and would provide transitional zones between
3-83
-------
the high water table levels of the above-grade clay settling areas and the
streams.
The sand/clay cap reclamation plan would have impacts on the regional Surfi-
cial Aquifer system, natural recharge rates and Surficial Aquifer water
quality similar to that of the proposed conventional plan.
Sand/Clay Mix Plan: The sand/clay mix plan would have 3,512 acres of sand/
clay mix (2:1), 3,185 acres of conventional clay settling areas with sand/
clay mix (2:1) cap, 2,095 acres of below-grade clay settling areas, 1,642
acres of above-grade clay settling areas, 1,740 acres of overburden fill and
3,020 acres of sand tailings fill with overburden cap. The dike configura-
tions would be similar to those of the proposed action.
The permeability of the 2:1 sand/clay mix material would be slightly greater
than that of clay alone, resulting in a small increase in recharge to the arte-
sian aquifer for the sand/clay mix plan compared to the proposed conventional
plan. The water retention capabilities of the reclaimed sand/clay mix mater-
ials would be essentially the same as clay. The re-establishment of the water
table in the 3,512 acres of sand/clay mix areas would be dependent on the
hydrologic gradient of the sand/clay mix and the adjacent materials.
The 3,185 acres of clay settling areas with sand/clay mix (2:1) cap would
develop a perched water table about five feet below the surface at the inter-
face of the clay and sand/clay mix material.
The above-grade and below-grade clay settling areas would retain water at or
near the surface. The areas would reduce natural recharge as described for
the proposed action.
The overburden fill areas and sand tailings fill areas would have high permea-
bilities that would allow rapid drainage. The effects of these areas on the
groundwater system would be the same as those described for the sand tailings
fill areas under the conventional clay settling plan.
3-84
-------
The sand/clay mix reclamation plan would have impacts on the regional Surfi-
cial Aquifer and local Surficial Aquifer water quality similar to that of the
proposed conventional plan.
Overburden Mix Plan: The overburden mix plan would have 5,492 acres of sand/
clay mix (2:1) areas, 2,847 acres of clay settling areas with sand/clay mix
(2:1) cap, 2,095 acres of below-grade clay settling areas, 1,740 acres of over-
burden fill areas, and 3,020 acres of sand tailings fill areas capped with
overburden. The dike configuration would be the same as the sand/clay mix
plan.
The 5,492 acres of sand/clay mix areas would have the same impacts on the
groundwater system as the sand/clay mix areas described under the sand/clay
mix plan. The sand/clay mix (2:1) areas would have a permeability slightly
greater than clay; therefore, the effects on the groundwater system would be
slightly greater natural recharge than for clay settling areas. The amounts
of below-grade clay settling areas, sand tailings fill areas and overburden
fill areas are equivalent to the sand/clay mix plan acreages. Therefore, the
overburden mix plan would have approximately the same impacts on groundwater
as the sand/clay mix plan, except there would be slightly greater natural
recharge.
3.4.2.2.6 Water Source Alternatives
Groundwater (Mobil's Proposed Action): During the 25 years of mining activ-
ity, water would be withdrawn for water supplies from the Lower Floridan
Aquifer (15.7 mgd) and from the Upper Floridan Aquifer (0.731 mgd), and for
dewatering purposes from the Surficial Aquifer. The withdrawals would lower
the water level in both the artesian and shallow aquifers, and would alter the
recharge from the shallow to the artesian aquifer. The effect of these
groundwater withdrawals has been discussed under previous sections (Mining
Methods, Matrix Transfer and Processing). The effects of the withdrawal rates
have been evaluated by SWFWMD through CUP No. 205403 and the proposed
withdrawal rates were approved.
3-85
-------
Recharge to the artesian aquifer from the Surficial Aquifer would be affected
both by lowering the water level in the artesian aquifer by pumpage and by de-
watering the Surficial Aquifer. The 15.7 mgd of groundwater withdrawn from
the Lower Floridan Aquifer would lower the piezometric surface beneath the
site an average of 3.3 feet. This drawdown would cause an increase in re-
charge to the artesian system underlying the total area of the proposed mine
site of about 0.2 inches/year. A local reduction in recharge due to dewater-
ing for mining operations would occur in the areas being mined. Calculations
using the aquifer characteristics determined in the baseline study indicate
that lowering the water table 38 feet by dewatering would decrease the re-
charge to the artesian aquifer 0.7 inches/year in the area of the mining pit.
The changes in recharge due to groundwater withdrawals and pit dewatering are
about equal per unit area and opposite in effect; therefore, little overall
change in recharge to the artesian aquifer due to these activites would occur.
Surface Water: If surface water were used for water supply, the piezometric
surface and water quality of the artesian aquifer would not be affected by
withdrawals of groundwater. Dewatering operations would be required to keep
the mine pit dry; therefore, the impacts to the water level and water quality
of the Surficial Aquifer would be the same as described for the proposed
action. When active mining ceases, the net impact on recharge would be the
same as for the proposed action.
3.5 SURFACE WATER
3.5.1 THE AFFECTED ENVIRONMENT
3.5.1.1 Regional Description
The Peace River originates from several lakes in the Green Swamp area of cen-
tral Polk County and flows in a general southwesterly direction through Polk,
Hardee, DeSoto, and Charlotte Counties for approximately 105 miles, entering
the Gulf of Mexico at Charlotte Harbor (Figure 3.5-A). Under average flow con-
ditions the river width varies from 60 feet to 200 feet and the depth varies
from 1.5 feet to 10 feet. River flows fluctuate widely with high flows typi-
cally occurring from late summer to early fall and low flows occurring in the
3-86
-------
FIGURE 3.5-A
MHN SWAMP AMA
ir- PROPOSElPsOUTH FORT
MEADE MINE FACILITY
I _POIIŁŁ0. ^
PEACE RIVER
and
TRIBUTARIES
SCALE!
! MILES
STUDY
POTENTIAL RESERVOIR SITES
CO PŤace River -
Whidden Creek
@ Peace River - Charlie
& Limestone Creeks
(3) Charlie Creek
(?) Horse Creek
S OUUCt: AMAWIM lit < IP A. 197S )
3-87
-------
spring during March and April; these flows reflect the influence of precipita-
tion cycles. The Peace River drainage basin encompasses approximately 2,300
square miles. Mobil's proposed South Fort Meade Mine is located within this
drainage basin. Point source discharges and runoff from agricultural, silvi-
cultural and recreational land uses affect the quantity and quality of water
in the Peace River (EPA, 1978).
3.5.1.2 Site Description
The project site extends along 4.5 miles of the east bank of the Peace River,
directly north of the Polk-Hardee County line. Bowlegs Creek, a major tribu-
tary of the Peace River, flows through the northeast section of the proposed
mine site and enters the Peace River north of the site. Seven small on-site
tributaries contribute to Bowlegs Creek's flow while three small tributaries,
Stephens Branch, Gurr Run, and Gilshey Branch, flow directly into the Peace
River from the project site. These tributaries and their associated drainage
basins are illustrated in Figure 3.5-B. The Bowlegs Creek drainage basin,
totalling 59 square miles, includes 7,061 acres or 43 percent of the project
site. Land in this basin is primarily pasture and woodlands; the less domi-
nant land uses are citrus production and phosphate mining. There are no
significant population centers or point source discharges in the Bowlegs Creek
drainage basin. The three tributaries that flow into the Peace River comprise
a combined drainage area of 5,089 acres or 31 percent of the project site.
Two other sub-basins, which include 4,138 acres or 26 percent of the project
site, drain to the south. These are part of larger drainage systems which lie
outside the project boundaries and eventually drain to the Peace River from
Little Charlie Creek.
3.5.1.3 Surface Water Characteristics
Water quantity and quality data were collected to determine baseline character-
istics of surface water in the vicinity of the proposed mine site. Baseline
water quantity data were established from water level and flow measurements
collected between June, 1979 and March, 1980 and from additional information
obtained from state and Federal agencies. Water quality data were collected
from April, 1979 to December, 1979; supplemental data from state and Federal
sources were also used.
3-88
-------
00
to
DRAINAGE BASINS
1134 ACRES
(7.0%)
KELLER RO
n
490 ACRES
(3.0%
OUTPARCELS (PRIVATELY OWNED!
1MILE
136 ACRES
(0.8%)
100 ACRES
(0.6%)
SOURCE: STUDY DATA
LEGEND
DRAINAGE BASIN BOUNDARY
TOTAL PROJECT SITE IS 16.288 ACRES.
OUTPARCELS ARE EXCLUDED FROM
ACREAGE FIGURES.
-------
3.5.1.3.1 Peace River
Average monthly flows, annual mean flows, flood flows, and-seven-day, ten-year
low flows for the Peace River at the northwest corner of the site upstream of
Bowlegs Creek are presented in Table 3.5-1. The mean annual average flow for
the Peace River is 134 cfs upstream of the site (above Bowlegs Creek) and 185
cfs downstream of the site (County Line Road).
In general, water quality in the Peace River appears to be poor near the
headwaters of the river but improves substantially downstream (FDER, 1980).
Data collected during the field survey (Table 3.5-2) reveal concentrations of
total phosphorus, fluoride, iron, lead, mercury, and oil and grease exceeding
either Federal or state criteria (Table 3.5-3) at some time. Dissolved oxygen
concentrations dropped below criteria levels on several occasions. The high
nutrient levels, potentially high fecal conform levels, and low concentra-
tions of dissolved oxygen are attributed to the existing point source dis-
charges upstream and nonpoint source loadings from mined areas, pastures and
citrus groves.
3.5.1.3.2 Bowlegs Creek
The flow rates for Bowlegs Creek correlate directly with the rainfall patterns
of the area; high flows occur in late summer and early autumn and low flows
occur in the spring. The calculated average monthly long-term flows, annual
mean flow, flood flows, and seven-day, ten-year low flow are presented in
Table 3.5-1. The annual average flow for Bowlegs Creek downstream of the site
is 46 cfs. The contribution of Bowlegs Creek to the Peace River's flow was 26
percent on an annual basis with the mean monthly contribution never exceeding
40.5 percent.
Water quality data collected for Bowlegs Creek are summarized in Table 3.5-4.
The stream's dissolved oxygen levels have, on occasion, dropped below the
state and Federal criteria. This can be attributed to nonpoint runoff from
pastures, citrus groves, and areas remaining barren after previous mining
operations. High total phosphorus, mercury, lead, cadmium, nickel, and zinc
levels also occurred during the sampling program. The high phosphorus levels
3-90
-------
TABLE 3.5-1
AVERAGE MONTHLY FLOWS FOR THE PEACE RIVER AND BOWLEGS CREEK
(Cfs)
Bowlegs Creek
Month
January
February
March
April
May
June
July
August
October
November
December
Annual Mean Flow
7-Day, 10- Year, Low Flow
25- Year Flood Flow
100- Year Flood Flow
Peace River'3'
74
82
108
28
86
132
219
224
139
76
85
134
11
5,871
8,554
Upstream
16
15
26
8
10
43
69
70
111
68
14
38
0
Downstream
19
19
32
9
12
52
83
85
134
82
16
46
0
2,880^
4,600(b)
(a) Flows were calculated by increasing Fort Meade flows by 1 percent.
Values represent Peace River flow immediately upstream of Bowlegs Creek,
(b) Flood flows were calculated for the creek section between upstream and
downstream monitoring station.
SOURCE: STUDY DATA AND USGS
3-91
-------
JTABLE 3.5-2
WATER QUALITY DATA SUMMARIES FOR PEACE RIVER
STATIONS WQ-7 AND FDER DATA COLLECTED AT COUNTY LINE ROAD
HQ-7
FDER DATA
(Station 125020008)
Parameter
Hater Level (ft)
Flow (cfs)
pft (units)
Carbon Alkalinity
(9/1 CaCO,)
Bicarbonate Alkal inlty
(8/1 CaCo,)
Temperature VC)
Dissolved Oxygen (mg/1)
Total Suspended
Solids
-------
TABLE 3.5-3
STATE OF FLORIDA AND FEDERAL WATER QUALITY CRITERIA
Alkalinity. Totil Ť
CaCQj (Bin.)
Alkalinity, Phenol-
oat halŤ1n
Aliorinin
Anaonia (non-ionized)
Anting ny
Arsenic
Bacteriological (Conform,
Totil and Fecal)
Beryllium
BOD (5-day)
Boron
Cadmium, uj/l
Chlorine
Chroeriun (Total)
Color (PCy)
Copper
Cyanide (Total), UJ/1
Detergents NBAS
Dissolved Ox/9*n (unn. )
Fluoride
Hydrogen Sulflde
Iron
LUC
Manganese
Mercury, ug/1
Nickel
Nitrogen, Nitrite - H
011s and Grease
Pesticides/Herbicides Scan
Alarin - Bielorin, u9/l
Chlordane, ug/1
2, * - 0
Z, Ť, 5 TP U9/1
DOT, uŤ/l
Demeton, uj/l
Enooiulfin. u9/1
Enarln, uj/l
CutMon, vj/l
Heptachlor, ug/l
Lindine, uo/l
Matitnlon, ug/l
Hetnoxycnlor, ug/l
M1nx. ua/l
ParatMon, ug/l
Toiiphene. ug/l
Phtmls
Pftthalate Esters
Phoiphata, Total as P
Polychlorlnated biphcnyls yj/1
0.05
Note 1
O.OS
0.5
0.5
10.0
0.05
s.o
Gross - activity
Radius - 226 pC1/l
Radlua - Z28 pC1/l
Selenium
Stiver ug/l
Specific Conductance uŤhd/ca
Total Suspended Solids
TurSidlty. JTU
line
6.0-8.5
0.001
15
5
5
IQCl tncreise
500 nax.
SO
1.0
F.A.C.
17-3
Class HI
20
20
1.5
0.02
0.2
1000/1OOnl.Tot.
200/100ml. Fee.
0.011
10
0.010
0.030
5
Marine Only
1.0
0.03
0.2
0.1
0.003
0.01
0.001
0.1
0.003
0.004
0.01
0.001
0.1
0.1
0.03
0.001
0.04
0.005
6.0-5.5
0.003
0.001
0.025
0.07
ZOO/100ml.
fecal
1.0
0.011 (Softwater)
1.100 (Hirdwater)
0.750
10 (Health)
12 (Aquatic life
softuitir)
0.010
O.OSO
75 (Health)
1.0
5
5.0
0.002
0.30
0.05
0.05
2 (Health)
0.5 (Freshwater life)
0.1
10
0 (Domestic water,
supply)
O.OC3
0.01
0.10
10
0.001
0.1
0.003
0.2 (Health)
0.004 (Aquatic life)
0.01
1.0
4.0 (Health)
0.01 (Freshwater life)
0.1
0.03
0.001
0.04
0.005
6.5-9.0
0.003
0.050
0.001
0.01
SO
Note 2
Note: All Concentrations are in milligram/Iiter unless otherwise noted.
1 Sufficiently loť to keep dissolved oxygen within lierits*
2 Ten percent maxinuff reduction in conensation depth fro" seasonal nom.
3-93
-------
TABLE 3.5-4_
WATER QUALITY DATA SUMMARIES FOR
BOWLEGS CREEK - STATIONS WQ-1 AND WQ-2
WQ-1
uq-2
(upstream)
Parameter
Water Level (ft)
Flow (cfs)
pH (units)
Carbon Alkalinity
(mg/l) CaCO,
Bicarbonate Alkalinity
(og/1) CaCO,
Temperature (eC)
Dissolved Oxygen (rag/I)
Total Suspended
Solids (mg/1)
Turbidity (NTU)
Total Dissolved
Solids 1 mg/1)
Conductivity [umho/cm)
Total Hardness
(mg/1) CaC03
BOO, (rag/1) 3
Ortnopnospnate (mg/l)
Total Phosphorus (mg/1)
Ammonia (mg/l)
Organ1c-N (mg/1)
Nitrate-N (mg/1)
Nitrlte-N (mg/1)
Total Nitrogen (mg/1)
Chloride (rag/1)
Fluoride (mg/1)
Sulfate (mg/1)
Sulfide (mg/1)
Barium (mg/1)
Cadmium (mg/1)
Chromium (mg/1 )
Copper
Iron (mg/1)
Lead (mg/1)
Mercury (mg/1)
Nickel (mg/1)
Selenium (rag/1)
Silver (mg/1)
Silica (rag/1)
Zinc (mg/1)
Pesticide Scan (mg/1)
Herbicide Scan (mg/lj
Detergent NBAS (mg/1)
011 a Grease (mg/1)
Total Gross Alpha
Activity (pC1)
Radium Alpha
Activity (pCi)
TOC (mg/1)
Max - Maximum value occurring
M1n - Minimum value occurring
Max Min
4.42 0.70
171.8 2.7
6.75 4.6
0 0
8 1
27.0 16.0
9.35 3.9
14 1
4.3 1.4
152 38
145 60
52 20
2.3 0.2
0.26 0.09
0.38 0.12
0.60 0.07
1.5 0.6
3.7 0.2 ,
0.03 <0.01
4.93 1.49
19.4 11.0
0.20 0.10
20.6 2.4
1.2 0.1
<0.01 <0.01
0.12 0.01
0.07 <0.05
C0.03 <0.03
0.74 0.12
0.04 <0.03
0.0207 0.0008
20.9 <0.06
0.037 <0.005
<0.03
-------
may be naturally occurring or may be attributed to nonpoint source runoff.
Reasons for the high trace metal concentrations are not apparent.
3.5.1.3.3 On-site Tributaries
The proposed mine site contains several small drainage systems resulting from
groundwater seepage and/or surface runoff. These small tributaries flow into
the Peace River and Bowlegs Creek and typically have their headwaters in wet-
land depressions. They have highly variable flows, corresponding to runoff
during seasonal rainfall and groundwater inflow. The estimated average
monthly flows (adjusted for long-term trends and flood flows) and seven-day,
ten-year low flows for each of the key tributaries are presented in Table
3.5-5. Annual flow contributions from the tributaries to their receiving
systems are small. The Peace River flow is increased by less than 2.3 percent
due to the on-site tributaries, and Bowlegs Creek's flow is increased by
approximately 13 percent.
Water quality data (Table 3.5-6) appear to be highly variable for several key
parameters including BOD5, dissolved oxygen, total organic carbon, total
nitrogen, and total suspended solids. Variability in these parameters is
common for streams such as these having extreme flow fluctuations. The upper
reaches of the tributaries exhibit high levels of nitrogen which can be attri-
buted to surface runoff from pasture areas. The high fluoride concentrations
in the lower stream sections may be due to increased groundwater seepage.
Conductivity and color patterns in the lower sections indicate a shift in in-
fluence from surface water or Surficial Aquifer to a deeper groundwater system,
3.5.1.4 Surface Water Utilization
EPA (1978) reported an absence of existing surface water withdrawal sites in
the Polk County portion of the Peace River basin. There are no significant
domestic or industrial water withdrawals, although some unpermitted with-
drawals for agricultural and other uses may exist.
3-95
-------
co
i
VO
TABLE 3.5-5
AVERAGE MONTHLY FLOWS
CALCULATED FOR SELECTED ON-SITE TRIBUTARIES
(cfs)
Maron Stephens
Run Branch
ML- 3 WL- 4
January
February
March
April
May
June
July
August
September
October
Nov enter
December
Annual Mean Flow
7-Day 10-Year Low Flow
25-Year Flood Flow
100-Year Flood Flow
0.5
0.5
0.9
0.3
0.3
1.4
2.3
2.3
3.7
2.2
0.5
0.3
1.3
0
310
400
0.4
0.4
0.7
0.2
0.3
1.2
1.9
1.9
3.0
2.2
0.4
0.3
1.1
0
922
1216
Gilshey
Branch
ML- 5
1.0
0.9
1.6
0.5
0.6
2.6
4.1
4.2
6.7
4.1
0.8
0.6
2.3
0
1626
2135
Mest Trtb
to Parker
ML- 6
1.1
1.1
1.8
0.5
0.7
2.9
4.7
4.8
7.6
4.6
0.9
0.6
2.6
0
-
-
East Trlb
to Parker
ML- 9
1.0
1.0
1.6
0.5
0.6
2.7
4.3
4.4
6.9
4.2
0.8
0.6
2.4
0
-
-
Gurr
Run
ML- 10
0.4
0.4
0.6
0.2
0.2
1.0
1.6
1.6
2.6
1.6
0.3
0.2
0.9
0
870
1140
Cypress
Area
ML- 11
0.3
0.3
0.6
0.2
0.2
0.9
1.5
1.5
2.3
1.4
0.3
0.2
0.2
0
-
-
- No Data Available
SOURCE: STUDY DATA
-------
TABLE 3.5-6
MEAN WATER QUALITY OF ON-SITE TRIBUTARIES
PARAMETER
Water Level (ft)
Flow (cfs)
pH (units)
Carbonate Alkalinity (mg/1 CaCO )
Bicarbonate Alkalinity (mg/1 CaCO )
Temperature (°C)
Dissolved Oxygen (mq/1)
Total Suspended Solids (mq/1)
Turbidity (NTU)
Total Dissolved Solids (mg/1)
Conductivity (n mho/cm)
Total Hardness (mg/1 CaCO )
BOD (mg/1)
Ortfiophosphate (mg/1)
Total Phosphorus (mg/1)
Ammonia (mg/1)
Organic-N (mg/1)
Nitrate-N (mg/1)
Nitrite-N (mg/1)
Total Nitrogen (mg/1)
Chloride (mg/1)
Fluoride (mg/1 )
Sulfate (mg/1)
Sulfide (mg/1)
Barium (rog/1)
Cadmium (mg/1)
Chromium (mg/1)
Copper (rog/1)
Iron (mg/1)
Lead (mg/1)
Mercury (mg/1)
Nickt-1 (mq/1)
Selenium (mg/1)
Silver (mg/1)
Silica (mg/1)
Zinc (mg/1)
Pesticide Scan (mg/1)
Herbicide Scan (mg/1)
Detergent MBAS (mg/1)
Oil S Grease (mg/1)
Total Gross Alpha Activity (pCi/1)
Radium Alpha Activity (pCi/1)
TOC (mg/1)
G1LSHEY
BRANCH
1.06
0.68
-
0
23.3
23.3
6.33
8.8
2.6
163.4
155
53
1.1
1.17
1.28
0.27
0.69
0.45
<0.01
1.36
22.3
0.46
21.9
0.6
<0.1
<0.03
<0.07
-------
The Central Florida Areawide Water Quality Management Plan (208 Study) identi-
fies two categories of wastewater dischargers to the Peace River Basin, i.e.,
domestic and industrial. Twenty-eight domestic dischargers with a total
design capacity of 31.39 mgd and 38 industrial dischargers with a total design
capacity of 927.61 mgd were identified upstream of the proposed mine site
(CFRPC, 1978).
3.5.2 ENVIRONMENTAL CONSEQUENCES OF THE ALTERNATIVES
3.5.2.1 The No Action Alternative
With the no action alternative no changes in the quantity of surface water are
expected in the area of the proposed mine. Seasonal changes in water level
and flow would continue without disruption, and the hydrologic characteristics
of the streams and rate of baseflow to them would remain the same.
Surface water quality with the no action alternative would be determined by
future land uses both on site and in the surrounding area. If land use
patterns remain as today, surface water quality might remain much as it is.
If other phosphate mines are constructed in the area, then surface water
quality of select streams may show increases in parameters such as specific
conductance, total dissolved solids, sulfate, and fluoride.
3.5.2.2 The Action Alternatives Including the Proposed Action
3.5.2.2.1 Mining Method Alternatives
Dragline (Mobil's Proposed Action): Dragline operations would require vege-
tation clearing on 50-acre tracts in front of each dragline. This would re-
sult in a small increase in surface water runoff flow and an increase in the
sediment contained in the runoff as a result of erosion. The amount of
cleared land should not exceed 100 acres at any one time, resulting in a
minimal effect on surface water.
During the mining process, land would be mined and then later converted to
waste disposal areas. This surface distruption would destroy the existing on-
site tributaries of the Peace River and Bowlegs Creek. (Reclamation of drain-
age basins and streams is discussed under Section 3.5.2.2.5, Reclamation
3-98
-------
Alternatives). Precipitation occurring on these disturbed areas would be
collected in the mine pits and disposal areas and directed to the recircula-
tion system until reclamation is completed, reducing the amount of runoff from
the site and thereby decreasing stream flows. The amount of disturbed land
would vary during the mine life with the maximum area disturbed occurring in
year 20 when approximately half the site would be in use for mining and waste
disposal (Figure 3.5-C). During this time, the reduction in flow to the Peace
River would be 8.5 cfs or 4.6 percent of the flow in the Peace River directly
below the site (discounting any discharge flow from the plant water system).
The maximum average flow reduction to Bowlegs Creek would be approximately 8
cfs or 17.4 percent of the flow in Bowlegs Creek as it leaves the property.
These flow reductions would be temporary with flows returning to normal at the
completion of mining and reclamation activities.
The reduction in surface runoff and flow in on-site tributaries would result
in a minor decrease in organic and nutrient mass loadings (BOD, TOC, total
phosphorus and total nitrogen) to Bowlegs Creek and the Peace River. The flow
reduction would reduce the organic load to the Peace River by 2 percent or
less and total phosphorus and total nitrogen by 1 percent or less. These
changes in surface water quality would be temporary, and the stream quality
is expected to eventually return to normal after mining and reclamation
activity ceases.
Bucket Wheel: The bucket wheel method of mining would have impacts on the
site and the adjacent waterways essentially identical to those of the proposed
action.
Dredge: The dredge mining method would also disrupt large areas of land
during the mine life. The effects of this disruption on surface water quan-
tity in the area would be similar to those described for the proposed action.
The dredge mining method would require large diked and flooded areas. During
the mining operation, the water level in the dredge pool would maintain the
water table level in the surrounding Surficial Aquifer and, therefore, main-
tain groundwater baseflow contribution to any stream in the immediate area of
3-99
-------
SOURCE: MOBIL
TOTAL DISTURBED ACREAGE
CONVENTIONAL WASTE DISPOSAL
r
a
r
a
10
14 16
MINE YEARS
I
24
26
28 30 32 34
I
- i
'. i
-------
mining. The dredging operation would increase the concentration of total
suspended solids, organic material, and inorganic material in the dredge pool
water. Adverse water quality impacts could occur if turbid water from the
dredge pond were released to surface waters.
3.5.2.2.2 Matrix Transfer Alternatives
Pipeline (Mobil's Proposed Action): Mining on the north side of Bowlegs Creek
would require a matrix slurry pipeline stream crossing of Bowlegs Creek during
a four year period of the mine life. If a break or leak occurred in the trans-
fer line at the stream crossing, suspended solids, nutrients and sediment
would be dramatically increased and smaller increases in Ra-226, specific
conductance, and total dissolved solids would occur in Bowlegs Creek. The
effects on water quality would be for a short time until corrective clean-up
action were taken. The use of valves and double-walled pipe as described in
Mobil's proposed action would minimize the potential for a spill occurrence at
the stream crossing.
Conveyor Belt: The potential for spillage of matrix material at a stream
crossing is also a possibility with the conveyor belt system. However, since
the material would be in a solid rather than slurried condition, the resulting
effects of a spill would be expected to be less than for the proposed action.
Truck: A spill resulting from matrix transfer by truck is possible but least
probable of the three alternatives. Should a spill occur it would amount to a
small volume of material in solid form. The resulting effects of a spill
should be minimal.
3.5.2.2.3 Matrix Processing Alternatives
Conventional Beneficiation (Mobil's Proposed Action): Several reagents would
be utilized during the feed preparation and flotation processes: sodium hydrox-
ide, fatty acid, fuel oil, sulfuric acid, amines and kerosene. The majority
of the reagents would react during the beneficiation process to form sul fate
compounds and would be discharged from the process in the waste sand tailings
and clays. The reagents used and the dilution ratio in the wastewater if the
3-101
-------
reagents passed through the flotation process without chemically reacting
would be as follows:
Reagent Dosage, gal/day Pi 1ut ion
No. 5 Fuel Oil 4,230 13,200:1
Fatty Acid 2,680 20,900:1
Sulfuric Acid 3,040 18,400:1
Amine 530 105,700:1
Kerosene 450 124,400:1
Caustic 190 294,700:1
Water from the sand tailings disposal areas would be introduced into the recir-
culation system where the reagent compounds would again be mixed with the
waste clays. The natural affinity of the reagents for phosphatic clay would
result in their adherence to the clay particles, leaving only trace amounts of
reagents in solution. The discharge from the clear water pool would contain
low concentrations of the reagents and reagent-sulfate compounds.
Waste sand and clay would be pumped in slurry form from the beneficiation
plant to waste settling areas. Should a leak develop in a transfer line,
flooding and potential surface water contamination could result. The only
stream crossing would be a sand tailings line crossing Bowlegs Creek occurring
in years 21 and 22 of the mine life. The crossing would be located in the
same area as the dragline crossing. Should a break occur at the crossing,
flow and sedimentation would increase in Bowlegs Creek for a short time until
corrective clean-up action were taken. There are no clay slurry lines cross-
ing surface water streams on the site, and the shortest distance between a
clay slurry line and any surface water stream (Bowlegs Creek or the Peace
River) would be approximately 3,000 feet.
Dry Separation: Processing the matrix by dry separation would not require
reagents, large quantities of water, or diked basins for water clarification.
Dry separation would have minimal potential for affecting surface water quan-
tity or quality.
3-102
-------
3.5.2.2.4 Waste Disposal Alternatives
Conventional Clay Settling Case (Mobil's Proposed Action): A primary concern
with above-grade settling basins is the potential for dike failure. In the
event of a failure, large volumes of clay could be discharged into Bowl egs
Creek and/or the Peace River increasing turbidity, destroying natural bio-
logical conmunities, depositing sediments, and raising the concentrations of
sulfates, fluorides, and total dissolved solids.
During the life of the mine, approximately 8,170 acres of above-grade clay
settling basins would be constructed with dike heights ranging from 25 to 45
feet and averaging 38.7 feet (Table 2.5-2). The worst case situation for a
dike failure would be when the greatest amount of active above-grade settling
acreage were in service. For the conventional clay settling case this occurs
in mine years 12 through 14 when five basins (CS-4, CS-5, CS-6, CS-7 and CS-8)
covering 2,790 acres are all active, operating in a flow through settling mode
(Figure 2.5-B and Table 2.5-3). Should a dam failure happen at this time, it
is estimated that 15,400 to 22,500 acre-feet of impounded clays could be
released. Because of the natural topography of the site, most of the clays
released would probably flow into Bowlegs Creek or the Peace River. It is
doubtful that any off-site property would be affected except for the roadways
that pass through the site. The primary effect would be to the on-site and
downstream sections of the Peace River and Bowlegs Creek. Spills could also
occur from other isolated clay settling areas. The primary effect would still
be degradation of water quality in the Peace River or Bowlegs Creek.
The technology used to construct the settling basin dikes has improved substan-
tially during the past decade, reducing the likelihood of a dike failure.
Thorough investigations of foundation and soil conditions at the location of
the proposed dikes would be conducted on the South Fort Meade site prior to
design and construction. The dikes would be continuously inspected and moni-
tored during the active life of the settling basins. Mobil would comply with
the regulations for design, construction and maintenance of earthen dams estab-
lished by the Florida Department of Environmental Regulation (FAC Chapter
17-9).
3-103
-------
Sand/Clay Cap Case: The sand/clay cap waste disposal case has dike configura-
tions similar to that of the conventional clay settling case; however, the
average dike height is decreased two feet (Figure 2.5-C, Table 2.5-5). Flow
through settling would not be practiced with this waste disposal case, there-
fore, the amount of above-grade settling acreage active at any one time is
reduced. Basin CS-3 would be used during the life of the mine as a dredge
basin and would be filled and emptied several times during the mining acti-
vities. The greatest amount of active above-grade settling occurs in mine
years 17 through 19 when CS-3 and CS-10, with a maximum area of 1,860 acres,
are active (Table 2.5-6). Should a dam failure occur at this time it is esti-
mated that 25,500 to 33,600 acre-feet of impounded clays could be released.
The potential for a dike failure occurring is decreased for the sand/clay cap
waste disposal case compared to the proposed action because of the reduced
active settling acreage (less than 1,860 acres compared to 2,760 acres).
The effect of a dam failure would be the same as that described for the pro-
posed action except that total quantity of clay that could potentially spill
would be reduced by 21 percent for the sand/clay waste disposal case compared
to the conventional clay settling case. This reduction results from the lower
average clay fill height with the sand/clay cap case (27 feet versus 34 feet).
Sand/Clay Mix Case: The sand/clay mix waste disposal case has 4,827 acres of
above-grade clay settling basins with dike heights from 40 to 48 feet, and
3,352 acres of above-grade sand/clay mix basins with dike heights from 20 to
37 feet (Tables 2.5-8 and 2.5-10). The 4,827 acres of above-grade clay
settling basins would be operated in a manner comparable to the sand/clay cap
case and could not utilize flow through settling since these areas will be
dewatered quickly in order to cap them with sand/clay mix. Two dredge basins
would be constructed to provide clay for sand/clay cap material as well as
sand/clay mix for the 3,352 acres of mix basins. The maximun amount of active
settling acreage (2,450 acres) is between that of the conventional clay
settling case (2,760 acres) and the sand/clay cap case (1,860 acres).
Therefore, the potential for a dike failure occurring is greater than the
sand/clay cap case but less than the conventional clay settling case.
3-104
-------
The sand/clay mix case has two types of above-grade basins: sand/clay mix and
conventional clay settling. The sand/clay mix material would consolidate more
rapidly and would have a higher density than the clay wastes impounded sepa-
rately. This increase in density and consolidation would result in a decrease
in flow characteristics of the mix material should a dike failure occur from
one of the mix basins. Therefore, the quantity of a sand/clay mix spill would
be less than that expected from a clay settling basin spill. If a dike fail-
ure occurred from one of the clay settling basins the effect would depend on
the quantity of material released but would be similar to that described under
the conventional clay settling case.
Overburden Mix Case: The configuration, size and active settling acreage of
above-grade basins with the overburden mix waste disposal case are similar to
the sand/clay mix case; however, the extent of sand/clay mix impoundments
would be increased to 5,492 acres. The average dam height would be 38 feet.
The potential for a dike failure and resultant effect on surface water streams
would be comparable to those described for the sand/clay mix basins under the
sand/clay mix case.
3.5.2.2.5 Reclamation Alternatives
Conventional Clay Settling Plan (Mobil's Proposed Action): The Peace River
and Bowlegs Creek would not be directly disturbed by the mining operation but
would be influenced by alterations to the site's drainage patterns. The on-
site tributaries and drainage areas disturbed by mining would be reconstructed
as close to the premining conditions as the reclaimed topography would allow
(Figure 2.6-A). A comparison of existing and post reclamation drainage areas
within the major drainage systems found on the South Fort Meade site is
summarized in Table 3.5-7.
The Peace River would receive five percent less direct surface drainage from
the site. Bowlegs Creek's drainage area from the site would be reduced by six
percent after reclamation. The Parker Branch drainage basin in the southern
part of the site would be enlarged by approximately 17 percent. These varia-
tions are not substantial alterations to the overall drainage patterns of the
3-105
-------
TABLE 3.5-Z
COMPARISON OF EXISTING AND POST RECLAMATION DRAINAGE AREAS
(Conventional Plan)
Waterways Receiving
Flow from On-Site
Tributaries
Existing Tributary
Drainage Area Average Flow
(acres) (cfs)
SOURCE: STUDY DATA
Post Reclamation
Drainage Area Average Flow
lacres) (cfs)
w Peace River
i
Q Bowl eg s Creek
Drainage to South
Parker Branch
Total
5,089
7,061
4,138
16,288
4.3
1.5
0
5.8
4,817
6,642
4,829
16,288
4.1
1.4
0
5.5
-------
site and since all the surface water eventually flows into the Peace River,
the total Peace River drainage basin and river flow would not be changed.
Approximately 60,000 linear feet of stream channels disturbed by mining would
be restored during reclamation. Reclaimed stream channels would be developed
in tailings fill with overburden cap or in overburden fill areas. These soil
compositions are the most suitable for establishing stable channels because
they are less susceptible to erosion and subsidence and can be successfully
reforested with native wetland species. The proposed plans provide for the
creation of a water level and an associated floodplain, similar to premining
conditions, which would allow effective conveyance of flood flows. Shallow
pools would be constructed at intervals of approximately 500 feet along the
length of the new channels. Above-grade reclaimed waste disposal areas would
drain to small marsh areas between 5 and 40 acres in size. These small
marshes would be connected by overflow swales to a reconstructed stream
channel.
Some minor alterations of surface runoff quantities and peak flows would be
observed after reclamation. The increased clay content of the reclaimed soils
in the 8,170 acres of clay settling areas would increase and, therefore, in-
crease the total runoff quantities and peak flows expected following a rain-
fall. The marsh areas at the discharge location of the basins and shallow
pools in the stream channels would provide some storage capacity and water
rention which would minimize the increases 1n peak flows. The runoff quanti-
ties and peak flows from the sand tailings fill areas (5,034 acres) would be
similar to the premining conditions.
After reclamation, stream water quality would be influenced primarily by
pollutants carried in the runoff. The site would be reclaimed for agricul-
tural and silvicultural uses. Small marsh areas established in the above-
grade reclaimed areas and two large wetland areas (totaling 1,513 acres) would
accumulate surface runoff from surrounding upland areas, trap sediment and
filter excess nutrients. As the reclaimed streams mature, the channels will
form natural meanders, and benthic communities will become re-established.
3-107
-------
The water quality found within the established reclaimed streams would be
similar to that presently found in the streams.
Sand/Clay Cap Plan: The surface water impacts resulting from the sand/clay
cap reclamation plan would not vary greatly from the impacts discussed for the
proposed action. Slight differences in the major drainage areas (Figure
2.6-F), as identified in Table 3.5-8, are associated with this case.
The total acreage of the above-grade clay settling areas would be the same as
with the conventional plan; however, 93 percent of these areas would be capped
with five feet of a 4:1 mixture of sand and clay and the remaining above-grade
clay settling areas would be capped with one foot of overburden. Runoff quan-
tities from these areas should not differ greatly from the premining conditions
due to the similar permeability and infiltration and, therefore, similar run-
off characteristics.
The total reclaimed and undisturbed wetland areas would be 2,057 acres which
is seven percent greater than provided with the proposed action. Stream
channel reclamation would be similar to that described for the proposed action
except for the reclaimed channel of Propps Branch where excavation and rough
grading would be done during final restoration when the surface sand/clay mix
(4:1) had consolidated to 30 percent solids. Further subsidence of this basin
and stream channel could create additional wetland areas along reclaimed
Propps Branch. Water quality should not differ substantially from the conven-
tional case due to the similar post-reclamation land use anticipated. How-
ever, less fertilizer would be required for agricultural uses with the sand/
clay cap plan than with the conventional case.
Sand/Clay Mix Plan: The sand/clay mix reclamation plan has surface water im-
pacts different from that of the proposed action resulting from differences in
the reclaimed drainage basin areas, wetland areas and the restoration of
Propps Branch. The major drainage basin areas under this case (Figure 2.6-H)
are identified in Table 3.5-9.
3-108
-------
TABLE 3.5-8
COMPARISON OF EXISTING AND POST RECLAMATION DRAINAGE AREAS
(Sand/Clay Cap Plan)
o
VO
Waterways Receiving
Flow from on-site
Tributaries
Existing Tributary
Drainage Area Average Flow
(acres) (cfs)
Post Reclamation
Drainage Area Average Flow
(acres) (cfs)
Peace River
Bowlegs Creek
Drainage to South
Parker Branch
TOTAL
5,089
7,061
4,138
16,288
4.5
1.5
0
5.8
4,817
6,762
4,709
16,288
4.1
1.4
0
5.5
SOURCE: STUDY DATA
-------
TABLE 3.5-9
COMPARISON OF EXISTING AND POST RECLAMATION DRAINAGE AREAS
(Sand/Clay Mix Plan)
OJ
I
Waterways Receiving
Flow from On-Site
Tributaries
Existing Tributary
Drainage Area Average Flow
(acres) (cfs)
Post Reclamation
Drainage Area Average Flow
(acres) (cfs)
Peace River
Bowlegs Creek
Drainage to South
Parker Branch
Total
5,089
7,061
1,138
16,288
4.3
1.5
0
5.8
5,306
6,273
4,709
16.288
4.4
1.3
0
5.7
SOURCE: STUDY DATA
-------
The sand/clay mix reclamation plan would provide 2,255 acres of wetlands, 343
acres more than the conventional reclamation plan. This would provide greater
water storage, filtering of nutrients, and removal of sediment.
The reclaimed stream channels would have a slightly different configuration
than with the proposed conventional reclamation plan. Reclaimed portions of
Propps Branch would be developed in a sand/clay mix (2:1) settling area.
Stream restoration could be difficult within this area due to the suscepti-
bility of the sand/clay mix to soil erosion. Other stream restoration would
be performed in overburden material with a high content of sand which does not
erode as easily as clay or 2:1 sand/clay mix. The unstable conditions in this
drainage basin could slightly increase the suspended solids loading to Bowlegs
Creek.
The sand/clay mix plan calls for 3,737 acres of clay surface, 3,020 acres of
overburden cap surface, and 7,237 acres of 2:1 sand/clay mixture surface. The
primary land uses anticipated for these areas are agriculture and silvicul-
ture, both of which are currently practiced. Constituent runoff loadings,
flow and other water quality parameters are not expected to be substantially
different from those anticipated for the proposed action.
Overburden Mix Plan: This reclamation plan would have similar drainage areas
and employ similar restoration techniques to those discussed for the sand/clay
mix plan. The primary change for this plan would be a greater surface area
with 2:1 sand/clay mixture surface. The overburden mix plan has 8,339 acres
of sand/clay mix surface while the sand/clay mix plan has 6,697 acres. This
should increase the surface permeability and reduce runoff flow quantities
from these areas. Wetland areas and stream restoration would be similar to
that of the sand/clay mix plan.
3.5.2.2.6 Water Source Alternatives
Groundwater (Mobil's Proposed Action): The major quantity of process makeup
water would be obtained from the Lower Floridan Aquifer. The impacts to sur-
face water systems would therefore be minimal.
3-111
-------
Surface Watery The use of surface water as the primary source of process water
could be accomplished by impounding Bowlegs Creek. If Bowlegs Creek were
impounded, the effect would be a severe flow reduction downstream of the
impoundment as well as a disturbance of the natural floodplains and wetlands
directly above and below the impoundment. Downstream flow reductions would
reduce the Peace River's flow by approximately 26 percent and would deprive
the river of natural nutrient and organic loads it presently receives from
Bowlegs Creek. A problem associated with using surface water as the primary
supply for processing is the need for additional water treatment.
3.5.2.2.7 Water Discharge Alternatives
Peace River (Mobil's Proposed Action): The primary discharge from the mining
area would occur from the 45-acre clear water pool adjacent to the processing
facility. Under the proposed plant siting, the clear water discharge would
flow into the Peace River by way of a vegetated drainage swale (outfall ditch)
constructed along the railroad spur route. The mine would have an intermit-
tent discharge from the clear water pool primarily between the months of May
through October, the months with increased rainfall. The discharged volume
would be directly dependent on the local rainfall. The months when discharge
is expected to be the greatest are June through September, a period when
tropical storms are frequent in Florida.
The main areas of concern for water quality include pH, total suspended solids
(TSS), total phosphorus and fluoride. The NPDES discharge data for Mobil's
existing Fort Meade Mine indicate no significant fluctuations in pH (values
range between 6.8 and 8.1 for the year). The discharge at the proposed mine
would have a similar pH range and should not degrade the water quality of the
receiving stream. Characteristic mass loadings (Table 3.5-10) were developed
for the proposed South Fort Meade Mine discharge based on the constituent
concentrations for the existing Fort Meade Mine discharge as well as other
phosphate mines in the area. The mass loadings were developed for a wet
season discharge of 9 mgd and a maximum discharge of 20 mgd, representing the
25-year storm event.
3-112
-------
CO
I
Parameter
Suspended Sol ids
Total Phosphorus
Fluoride
Suspended Solids
Total Phosphorus
Fluoride
Suspended Sol ids
Total Phosphorus
Fluoride
TABLE 3.5-1Q
.IMPACT OF CLEAR WATER POOL DISCHARGE ON THE PEACE RIVER
BASELINE CONDITIONS
MINING CONDITIONS
Concentration
lmg/1)
Mass loading
(kg/day)
Concentration
(mg/1)
Mass Loading
(kg/day)
(Peace River at Station W()-7)
Upstream
30 19,747
(Peace River at Station WQ-7)
Upstream
30 19,747
1.9
1.1
1,251
724
1.9
1.1
1,251
724
(Existing Mass Loading From Project Site)
45.3
3.9
1.3
(Existing Conditions Downstream of Project Site)
30 19,792
1.9 1.255
1.1 725
(Estimate of Mine Effluent)
25 853
3 102
2 68
(Mine Effluent Mixed In Peace River)
30 20,600
2-0 1,353
1.2 792
Calculations are based on the following assumptions:
o Mean Peace River flow rate at the Fort Meade Station between June through September is considered to be 172 MGD.
o Mean constitutent concentrations found in the Peace River at Station HQ-7 (Peace River below Bowlegs Creek
confluence) for the months of June through September are: suspended solids 30 mg/1, total phosphorus 1.9 mg/1 and
fluoride 1.1 mg/1. These values were derived from baseline data collected in the months of June and August 1979.
o Constituent concentrations and flows for all three tributaries flowing directly to the Peace River are similar to
those derived for Gilshey Branch (constituent mass load for Gilshey Branch x 3), and that the five major on-site
tributaries flowing to Bowlegs Creek are similar enough to those derived for Maron Run to represent the total
contribution from the project site to the creek (constitutent Ťass load for Maron Run x 5).
o Mixing of the mine effluent with the river flow is complete, resulting in a homogeneous mixture .
o Average daily discharge from mine in year having normal rainfall is 9 MGD.
o Estimated mean flow from on-site tributaries between June and September 1979 is 0.77 MGD.
SOURCE: STUDY DATA
-------
An evaluation of the present surface water characteristics and the projected
characteristics during mining operations indicates that when the mine effluent
is mixed with the Peace River's average.flow between June and September, the
concentrations of TSS, total phosphorus and fluoride are 30 mg/1, 2 mg/1 and
1.2 mg/1, respectively (Table 3.5-10). These values are very similar to those
naturally occurring from the mass loadings of the existing tributaries. The
calculations are based on average river flow during a year with normal rain-
fall patterns. Average flow conditions are used instead of low flow condi-
tions because discharge from the water system results from high rainfall
events or periods when high river flows would be expected. The loading can be
much greater or much less, depending on the rainfall trends. Discharge flows
are based on normal flows derived during the mine year when the largest area
will be included within the recirculation system. Before and after this peak
year, less of the mine site will influence the waste discharge and more acre-
age within the site will contribute direct runoff to the streams.
There would be additional outfalls associated with the spillways of individual
settling basins, but these would only discharge to Bowlegs Creek and Stephens
Branch in extreme circumstances when excessive rainfall is anticipated to over-
top the basins. Over the active mining period, the location of the emergency
discharge outfalls would shift as basins are reclaimed. The quantities of con-
stituents that might be released from an emergency spillway, while lowering
the water levels in the basins to create capacity for a threatened excessive
rainfall (a hurricane, for example), would depend on the total area of basins
in use, and that area will change over the life of the mine operation. Table
3.5-11 presents the worst case existing concentration of water quality para-
meters of concern for the Peace River, Bowlegs Creek, Stephens Branch and the
expected concentration of these same parameters in clay settling pond superna-
tant waters. The only Florida water quality standard (Table 3.5-3) that might
be violated by discharge of clay settling pond supernatant was specific conduc-
tance. If this stream were discharged to Bowlegs Creek, the average discharge
rate would have to be less than about 53 cfs (105 acre-feet/day) to avoid ex-
ceeding the allowable 100 percent increase in specific conductance. (This
assumes a flow of 60 cfs in Bowlegs Creek, a typical flow during the summer
3-114
-------
I
I
>-"
in
TABLE 3.5-11
COMPARISON OF THE SURFACE WATER QUALITY NEAR THE SOUTH FORT MEADE MINE SITE
TO MEASURED VALUES IN CLAY SETTLING AREA DISCHARGES
Constituents' '
pH, (units)
Specific Conductance,
uhos/on
Total Dissolved Solids
Calcium
Magnesium
Sodium
Potassium
Bicarbonate
Sul fate
Chloride
Iron
Silica
Fluoride
Nitrate, as N
Total Phosphorus
Radium-226, pCi/1
(7\
Peace R1verv '
6.6-7.7
310
163
-
-
-
-
42
56
19.6
0.4
2.3
1.4
l.U
2.5
<0.8
Bowlegs Creek* '
4.7-7.2
168
117
-
-
-
-
4
12.5
14.4
0.5
3.7
0.2
l.b
0.3
<1.8
Stephens Branch
-
101
127
-
-
-
-
7.9
8.8
17.3
0.4
4.2
0.4
1.2
0.9
2.4
Clay Settling Area
Supernatant' '
7.8
523
348
57
22
18
1.3
112
144
17
0.119
2.5
2.0
1.06
0.09
0.67
Units are mg/1 unless otherwise noted.
2Peace River WQ-7 Station (June, 1979-March, 1980)
3Bowlegs Creek WQ-2 Station (June, 1979-March, 1980)
4
Lament, et al. 1975. Characterization Studies of Florida Phosphate Slimes.
SOURCE: U.S. EPA, 1979. Development Document for Effluent Limitations Guidelines and Standards, Mineral
Hining and Processing Industry, Point Source Category.
-------
when excessive rain would be expected.) Discharge into Bowlegs Creek would
increase the concentrations of specific conductance, total dissolved solids,
bicarbonate, sulfate, chloride, and fluoride. Discharge into Stephens Branch
would increase the concentration of specific conductance, total dissolved
solids, bicarbonate, sulfate, and fluoride.
If the clay pond supernatant were discharged to the Peace River during the
summer when the river flow typically might be 150 cfs, a discharge of about
1,230 cfs (2,430 acre-feet/day) would not raise the specific conductance of
the river to the maximum of 500 umhos/cm (Table 3.5-3). Discharge into the
Peace River would increase the concentrations of specific conductance, total
dissolved solids, bicarbonate, sulfate, silica, and fluoride.
Bowlegs Creek; The discharge characteristics would be the same if the primary
water discharge is directed to Bowlegs Creek instead of the Peace River.
Because the flow in Bowlegs Creek is substantially less from that of the Peace
River, the impact of the waste load would be greater. The mine discharge
would increase the creek's average flow immediately downstream of the site
from 24.6 mgd (38 cfs) to 33.6 mgd (52 cfs). This increase in flow could
cause additional scouring of the stream channel which would alter the existing
biological communities found in the creek. The additional flow would also in-
crease the area affected by flooding during storms.
An evaluation of the effects of discharging to Bowlegs Creek indicates that
concentrations of the three water quality parameters of concern would increase
slightly with the introduction of the mine effluent. The TSS concentrations
after mixing would increase from 10 mg/1 to 14 mg/1, the total phosphorus con-
centration would increase from 0.24 mg/1 to 0.98 mg/1, and the fluoride
concentration would increase from 0.14 mg/1 to 0.64 mg/1.
The effluent discharged to Bowlegs Creek would eventually flow into the Peace
River. The impact on the river will be even less discernible than that pre-
viously discussed due to the additional dilution and mixing of the effluent
prior to its entry into the river.
3-116
-------
3.5.2.2.8 Product Transport Alternatives
Railroad (Mobil's Proposed Action): A concern associated with rail transport
is the potential of a spill occurring at the Peace River crossing. If such an
event should occur, phosphate rock would enter the stream, increasing suspen-
ded solids and sediment material and temporarily degrading the water quality
of the river.
Truck: Truck transport of the phosphate rock would affect surface water in the
same way as rail transport in the event of a spill. The size of a potential
spill with a truck would be less than with rail transport.
3.6 BIOLOGY
3.6.1 THE AFFECTED ENVIRONMENT
3.6.1.1 Regional Setting
The proposed South Fort Meade Mine site is a part of the Central Florida
Highlands biogeographic region, one of the seven major biogeographic regions
of Florida. Over half of the annual precipitation of this region is received
in the period June through September, which is the middle and latter part of
the growing season for most vegetation. Faunal movement and habitat use
patterns are also related to this cycling of wet and dry seasons. The region
is a transition zone supporting both temperate and subtropical species.
3.6.1.2 Site Description
Based on the Florida Land Use and Cover Classification System (Kolb et al.,
1976), thirty land use and cover classification types were identified on the
proposed South Fort Meade Mine site (Figure 3.6-A and Table 3.6-1). The cover
types may be grouped into the following four categories:
3-117
-------
LAND USE AND COVER
BASED ON THE FLORDA LAND
USE AND COVER CLASSFCATCN
LEGEND
110 RE8OENTML
1*4 ABANDONED MME
210 CROPLAND/PASTURELAND
23O CITRUS
410 CONFEROUS FOREST
420 HARDWOOD FOREST
430 MXEO FOREST
440 PI-ANTED FOREST
440 CLEARCUT
900 WATER
10 WETLAND - CONrEROUS FOREST
820 WETLAND - HARDWOOD FOREST
40 WETLAND - VEGETATED. NON-FORESTED
Further duiMulton* mŤy be found In Table 3.6-1
SOURCE: STUDY DATA
-------
TABLE 3.6-1
EXISTING ACREAGE BY LAND USE AND COVER TYPE
(Acres)
Symbol
111
194
211
212
213
231
4111
4121
4221
4222
4223
4224
431
4411
4412
4413
451
531
560
563
6111
6211
6212
6213
6214
6215
6221
6222
6411
6412
Land Use &
Cover Type
Urban, single unit, low density
Abandoned mine piles
Row crops
Field crops
Improved pasture
Orange groves
Cutover flatwoods, palmetto range
Cutover longleaf pine/sandhill oaks
Live oak, mixed understory
Live oak, bahia understory
Upland mesic
Transition mesic (bottomland
hardwoods)
Mixed forest
Planted pine - no ground vegetation
Planted pine - bahia ground cover
Planted pine - flatwoods understory
Clearcut bayhead
Unvegetated reservoirs
Other water areas
Cattle water ponds
Pond cypress, isolated
Gum-maple swamp
Bayhead
Bay strand
Myrtle thicket
Mixed hardwood swamp
Disturbed gum-maple swamp
Disturbed bayhead
Isolated upland depressions
Wetland depressions
TOTAL
Existing
Acreage
4
214
810
30
6,876
566
3,389
24
109
118
660
917
126
17
204
118
39
3
3
6
78
185
418
23
21
198
8
84
883
157
16,288
SOURCE: STUDY DATA AND FLORIDA LAND USE AND COVER CLASSIFICATION SYSTEM
3-119
-------
Category Acreage Percent
o Land Communities (15 land use types) 14,004 86.0
o Land-Water Interface Communities
(10 land use types) 2,054 12.6
o Water Communities (3 land use types) 12 0.1
o Developed Areas (2 land use types) 218 1.3
Total 16,288 100.0
The characteristics of native vegetation on the site have been altered by
human activities. Water communities on the proposed mine site include man-
made and naturally occurring ponds which are used for watering cattle and are
stagnant and eutrophic. The Peace River and Bowlegs Creek, both of which are
detrital-based heterotrophic systems (organisms consuming decaying matter),
are included in the water community discussions but acreages were not esti-
mated. Developed land (abandoned mines and residential areas), accounting for
1.3 percent (218 acres) of the total acreage, is excluded from this discussion.
3.6.1.2.1 Land Communities
Seven major types of land communities occupy 86 percent (14,004 acres) of the
total acreage (16,288 acres) of the site.
Percent of Total
Type Acreage Site Acreage
Coniferous Forest 3,413 20.9
Hardwood Forest 1,804 11.1
Mixed Forest 126 0.8
Planted Forest 340 2.1
Cropland/Pastures 7,716 47.4
Clearcut 39 0.2
Citrus 566 3.5
Total 14,004 86.0
3-120
-------
Coniferous, hardwood, and mixed forests are found primarily in narrow strips
along the property boundary, while agricultural areas occupy the interior
portion of the site. Agriculture (cropland, pastures, and citrus) is the
predominant land use on the site, accounting for 51 percent (8,282 acres) of
the total acreage.
Coniferous Forest: Coniferous forest communities on the site are represented
by two distinct types: cutover pine-palmetto flatwoods (3,389 acres) and cut-
over longleaf pine-sandhill oak (24 acres). In both communities, periodic
fires serve to control plant species composition and release mineral nutrients
to the soil. Controlled burning is a common practice for improving cattle
grazing and timber production. Both communities have been moderately to heav-
ily logged, and as a result their biomass has been reduced. Cattle foraging,
ditching, and road construction have modified local water regimes and altered
remaining understory associations, resulting in local invasion by hardwoods
and low floral and faunal diversity. Decreased plant diversity and biomass
have reduced the nutrient recycling function of this community by decreasing
the amount of plant material available for decay and release of nutrients.
Animal species most commonly occurring in these communities include the
nine-banded armadillo, hispid cotton rat, pine warbler, rufous-sided townee,
pine woods treefrog and black racer.
Hardwood Forest: Four subtypes of the hardwood forest association exist as
components of either xeric (dry) or mesic (moist) hammocks on the site. The
xeric hammock type is represented by live oak with mixed understory (109
acres) and live oak with bahia understory associations (118 acres). Plant and
animal diversity are typically low in these communities. The upland mesic
association (660 acres) is a transition between the xeric live oak associa-
tions and bottomland hardwoods (917 acres). Heavy cattle usage has reduced
the level of plant and animal diversity and productivity in these associa-
tions. Typical wildlife species occurring in these associations include the
eastern mole, gray squirrel, green snake, oak toad, pileated woodpecker and
red-bellied woodpecker.
Mixed Forests: The mixed forest communities (126 acres) occupy well-drained
sandy soils along the Peace River and Bowlegs Creek. Secondary growth of
3-121
-------
mixed forest has occured on previously logged hardwood forest areas. On the
interior of the site, mixed forests have developed as a result of fire sup-
pression or.ditching to improve drainage in natural pinelands. Plant and
animal diversity, biomass, productivity and nutrient availability in the mixed
forests range from low to moderate. The blue jay, rufous-sided towhee, spade-
foot toad, black racer, gray squirrel and southeastern pocket gopher are
common inhabitants of this community type.
Planted Forests: Plantation pines (340 acres) are established on the site as
row plantings in areas that have been burned, harrowed and cleared of vegeta-
tion. Plantations without ground cover or with bahia understory have low
plant and animal diversities. Planted pine plantations with flatwoods under-
story have moderate plant diversity and low to moderate animal diversity.
Cropland/Pasture: Crop!and/pasture is the predominant land use on the site,
accounting for 7,716 acres, or 47 percent of the site, consisting of 6,876
acres of pasture and 840 acres of cropland. Grasses, the dominant vegetation
cover, have replaced much of the native vegetation and are managed to increase
productivity. The soil-binding root systems of pasture provide erosion and
runoff control. Plant and animal diversity and biomass are generally low.
Clearcuts: The clearcut bayhead (39 acres) on the site occupies a shallow
depression which formerly was a seepage outcrop zone. The seepage outcrop
zone was the result of lateral, water table percolation from the adjacent
sandy ridge which is now covered by improved pasture and orange groves. The
absence of vegetative cover on this area results in a lack of plant diversity,
biomass and wildlife useage.
Citrus: Citrus groves occupy 566 acres or 3 percent of the site. Most groves
on the site are not at peak production due to advanced age, ground cover or
poor management practices. Because citrus is an intensively managed cover
type, plant diversity is low and the animal diversity varies seasonally with
fruiting.
3-122
-------
3.6.1.2.2 Land-Water Interface Communities
The land-water interface communities on site consist of three types. The
acreage of each type is as follows:
Percent of Total
Type Acreage Site Acreage
Wetland-coniferous forest 78 0.5
Wetland-hardwood forest 937 5.7
Non-forested, vegetated wetlands 1,040 6.4
Total 2,055 12.6
Forested wetland associations on site are scattered and occur primarily along
streams. Vegetated, nonforested wetlands occur as small, isolated units in
the site interior. Deep freshwater marshes function as the headwaters of
streams in the south central portion of the property.
Wetland-Coniferous Forest: These communities exhibit zoned internal structure
and develop in shallow plateau depressions where rainfall is the principal
source of water. The depressions contain acidic, poorly buffered waters and
are minimally influenced by groundwater. Complete drying of the depressions
is common during the dry season, and flooding results from wet season rain-
fall. The associations on the site are a small three-acre stand and a large
75-acre cypress dome near the eastern boundary (Figure 3.6-A). Animal species
found in these communities include least killifish, eastern mosquitofish,
green treefrog, squirrel treefrog, white-eyed vireo and opossum.
Wetland-Hardwood Forest: Bayheads (525 acres) and mixed hardwood swamps (411
acres) are the major wetland forest associations on the site. Bayhead communi-
ties exist along tributaries where erosion of highly permeable sandy soils has
cut below the top of the water table. These stands occur on sloping ground
which drains to streams only during heavy precipitation. Mixed hardwood swamp
associations on the site represent second growth stands in previously burned
or logged bayheads. Both associations provide limited flood protection, sedi-
ment filtering and water purification. The isolated and altered nature of the
3-123
-------
communities minimizes wildlife habitat value. Wildlife species which usually
occur in these communities include the cotton mouse, raccoon, blue-jay, barred
owl, little grass frog and striped swamp snake.
Met!and-Vegetated, Nonforested: Nonforested vegetated wetlands are repre-
sented on the site by shallow (883 acres) and deep water marshes (157 acres).
Shallow marshes, or wet prairies, are flooded seasonally. The shallow marsh
systems occur as numerous, small (approximately 10 acres or less) isolated
depressions on the site. During prolonged rainfall, these depressions over-
flow and eventually drain into streams. Deep water marshes are characterized
by floating-leaf aquatic species and generally develop on the margins of
ponds, lakes, open marshlands and sloughs. The deep marsh usually has perma-
nent standing water in some areas. Both marsh associations have been affected
by cattle grazing and trampling. Wildlife species usually occurring in these
communities include the rice rat, greater siren, chorus frog, and cottonmouth.
The eastern mosquitofish, least killifish and everglades pygmy sunfish were
collected from the deep marsh systems.
3.6.1.2.3 Water Communities
Both lentic (standing) and lotic (flowing) water communities occur on the
proposed mine site. Lentic communities occupy less than 6.4 acres (0.1 per-
cent) of the site and include man-made ponds and naturally occurring ponds.
These ponds are eutrophic, supporting numerous algal blooms and exhibiting low
plant and animal diversities. The primary function of the on-site ponds is
water storage for cattle. Lotic communities include the Peace River, Bowlegs
Creek and several small intermittent tributaries. Lotic systems on and ad-
jacent to the site are detrital-based, heterotrophic systems and are typical
of aquatic communities in the region.
Adjacent to the site the Peace River exhibits a steep gradient with increased
stream flow and unstable substrate, resulting in lowered floral and faunal
diversity. Water quality has been degraded as a result of agricultural, indus-
trial and urban waste input. Bowlegs Creek provides drainage of surface run-
off from much of the site. It has been altered by channelization and previous
impoundment. On-site tributaries are intermittent with average annual flows
of less than 5 cfs at the property boundary. They are limited in productivity
3-124
-------
and plant and animal diversity, and their primary benefit to the site is con-
veyance of excess water off of the property. Due to these factors, nutrient
input to downstream areas and the streams' capacities to function as biolo-
gical reservoirs for colonization of downstream areas are limited.
Peace River: The headwater region of the Peace River is characterized by a
wide, easily flooded valley dominated by water-tolerant vegetation. Beginning
in the vicinity of Fort Meade, the main channel is deeply incised with very
few flood channels. The wetland zone is extensive downstream from Fort Ogden
to the river's mouth. On the site, wetlands are either isolated from the
river or limited to a narrow strip bordering the river. Flood flows generally
are contained within the banks. These two factors limit the detrital input to
the Peace River from the proposed mine site.
The algal community of the Peace River is qualitatively diverse but quantita-
tively low due to the natural dark brown color and the turbidity of the water,
both of which limit light penetration. Aquatic macrophyte distribution and
abundance in the Peace River adjacent to the proposed mine site are highly
variable, depending on light and stream velocity. Forty-four benthic macro-
invertebrate taxa were collected from the three areas of the Peace River. The
major groups collected were oligochaetes (aquatic earthworms), dipterans
(flies, mosquitoes, and midges) and molluscs (clams and snails). Diversity
values (Shannon-Weaver) ranged from zero to 2.49 (values above three indicate
unpolluted waters and values below one indicate polluted water) and equita-
bility values (McArthur's Broken Stick Model) ranged from zero to 0.88 (values
of 0.5 or less indicate degradation). Marked differences between sampling
periods may be the result of sampling efficiency during high flow conditions
and not seasonal effects. Diversity and equitability values indicate that the
Peace River is a moderately stressed environment.
The Peace River basin contains at least 72 species of fish; about 35 species
are present in southern Polk County. One exotic fish species, blue tilapia,
is believed to be present in the Peace River near the project site. Waterfowl
and wading birds are the primary bird groups found in this basin. Amphibians
and reptiles include water snakes, turtles, frogs and alligators common to
central Florida.
3-125
-------
Bowlegs Creek: Bowlegs Creek is the largest sub-basin within the proposed
mine site, occupying 43 percent of the site. Lake Buffurn and Boggy Branch are
the principal contributors to the creek system. Seven intermittent tributa-
ries within the site also contribute to the creek's flow. A portion of the
creek on the site has been channelized and was at one time impounded. Other
influences on Bowlegs Creek include agricultural runoff, phosphate mining
and the detrital input from adjacent wetlands during extreme precipitation
events.
Bowlegs Creek, with its seasonal flow regimes, is similar to other detrital-
based systems in the region with low to moderate floral and fauna! diversity.
Algal and aquatic macrophyte communities are similar to those occurring in the
Peace River. These communities are limited by decreased light due to canopy
overhang and dark coloration of the water. The channelized area where canopy
overhang has been eliminated, however, supports a diverse algal and aquatic
macrophyte community.
A total of 49 benthic macroinvertebrate taxa were collected from Bowlegs Creek
during the two sampling periods. Oligochaetes, dipterans, molluscs, and
coleopterans (beetles) were the major groups collected. Diversity values
ranged from 1.13 to 3.6, and equitability values ranged from 0.29 to 1.07.
Diversity and equitability values indicate that benthic communities in Bowlegs
Creek are less stressed than those of the Peace River.
Eighteen fish species were collected from three sampling sites on Bowlegs
Creek. The most abundant fish collected were the eastern mosquitofish, golden
topminnow, southern brook silverside, and bluegill and other sunfish.
On-Site Tributaries: The headwaters of the ten tributaries found on the site
originate in plateau depressions. The channels tend to be deeply incised and
several have been channelized to enhance drainage. The annual average flows
are less than 5 cfs and the tributaries exhibit highly variable flows due to
seasonal rainfall and Surficial Aquifer seepage. These variable flows limit
biotic community stability. Canopy overhang limits light penetration, which
is important to algae communities, thereby decreasing primary production.
These tributaries serve primarily as conveyors of excess water that accunu -
lates in the plateau depressions during precipitation.
3-126
-------
Algae and aquatic macrophyte communities of the intermittent tributaries are
limited by poor light penetration due to dense canopy overhang. Fifty-eight
benthic macroinvertebrate taxa were collected during two sampling periods on a
representative tributary. Oligochaetes, molluscs, and dipterans were the domi-
nant groups collected. Species diversity values ranged from 3.26 to 3.45 and
equitability from 0.3 to 0.8. These diversity and equitability values indi-
cate a relatively unpolluted (low oxygen demand) system.
Eleven species of fish were collected from the on-site tributaries that were
sampled. The eastern mosquitofish and sail fin molly were the most commonly
encountered species. The species found in the tributary systems are generally
tolerant of low dissolved oxygen conditions.
Ponds: The proposed mine site contains both man-made and naturally occurring
ponds. Cattle ponds exhibit low vascular plant and animal abundance and diver-
sities due to cattle grazing and trampling. The ponds generally are eutrophic
because of the high nutrient input from cattle use. Algal community abundance
is high with many ponds supporting algal blooms. Naturally occurring ponds
are fed by surface runoff and Surficial Aquifer seepage, and they occasionally
go dry. The man-made ponds generally contain water year-round, and during
extreme rains, the ponds serve as a source of nutrients and excess water to on-
site tributaries. The water quality benefit provided by the ponds, however,
is negligible due to their eutrophied condition.
3.6.1.2.4 Forestry and Agricultural Resources
On the site, agricultural resources, including pasture, cropland, and citrus,
total 8,282 acres. Of the agricultural land, 6,876 acres are in improved pas-
ture supporting a variety of native and introduced grasses. Row crops and
field crops comprise 840 acres. Row crops are grown on several commercial
farms near the southeast corner of the site. None of the soils on the site
are designated as prime agricultural soils.
Citrus groves, primarily oranges, occupy 566 acres along Mt. Pisgah Road and
in the northeastern corner of the site. Most of these groves are not at peak
production due to advanced age and lack of adequate management. The Soil
Conservation Service (SCS) has designated 446 acres of orange groves on the
3-127
-------
site as unique citrus areas. This acreage constitutes less than 0.5 percent
of the unique citrus areas in Polk County.
Planted pine (slash pine) occupies approximately 340 acres (2.1 percent of the
site). A survey of the forestry resources indicates that the site contains
the equivalent of 4,153 cords of wood.
3.6.1.2.5 Migratory Wildlife and Game Species
Large game species potentially present on the site include the feral hog and
the white-tailed deer. The feral hog population appears abundant on the site;
however, no white-tailed deer were observed. Small game species consist
primarily of mourning doves, bobwhites, gray squirrels, eastern cottontails
and marsh rabbits. Fur-bearing species include the raccoon, bobcat, fox and
skunk. Although the site is on the migratory flyway, the poor quality of
marshes and the small size of water bodies preclude any appreciable use of the
site by migratory ducks, wading birds or other waterfowl.
3.6.1.2.6 Rare and Endangered Species
Federally Threatened or Endangered Species: EPA provided the U.S. Fish and
Wildlife Service, Jacksonville, Florida office with a description of Mobil's
South Fort Meade Mine project and requested a list of endangered and threat-
ened species which might occur in the project's area of influence (December
12, 1980). The U.S. Fish and Wildlife Service responded (December 18, 1980)
to the EPA request with the following listing of species believed to be
present in the area:
Bald Eagle - Endangered
Red-Cockaded Woodpecker - Endangered
Eastern Indigo Snake - Threatened
American Alligator - Threatened.
A summary discussion of each of the wildlife species' habitat requirements and
their occurrence in the region is presented in the following paragraphs. No
Federally threatened or endangered plant species were identified on site.
Southern Bald Eagle: The southern bald eagle is usually found in riparian
habitats. The species nests are usually located near large bodies of water,
3-128
-------
although 1n the Florida Interior they may nest on ponds and marshes. An eagle
nest is present near the northeastern site boundary, but is not within the
project boundaries (see Section 7, Figure 7.3-A). The proposed mine site does
not have nesting habitat characteristic of this species, but may have areas
being utilized for feeding.
Red-Cockaded Woodpecker: Red-cockaded woodpeckers are generally associated
with mature to overmature longleaf pine stands. No mature stands of other
pines which could provide habitat for this species exist on the site. There
were no observations or reported sightings of this species. It is concluded
that the possibility of a red-cockaded woodpecker occurring on the proposed
mine site is extremely low to nonexistent.
Eastern Indigo Snake: The indigo snake was observed on the proposed mine
site. This species prefers mesic forests and hardwood wetlands. They are
also found in xeric habitats associated with burrows of the gopher tortoise
and other species. The five sightings of indigo snakes were in mesic habitats
along Bowlegs Creek, the Peace River, and near the on-site tributaries.
American Alligator: Alligators occur in small populations on the proposed
mine site. This species is rather adaptive and was observed in a few cattle
ponds and drainage canals. Poaching was evident as one alligator was found
shot. There is adequate alligator habitat on the site but the habitat dis-
turbances associated with cattle production have restricted this species'
distribution on the property.
State Rare and Endangered Species: Twenty-four protected plants listed as
endangered, threatened, or of special concern under Florida Statute 581.185
(Preservation of Native Flora of Florida) occur on the proposed mine site.
The stated intent of Florida Statute 581.185 is "...to provide an orderly and
controlled procedure for harvesting native flora from the wilds, thus prevent-
ing wanton exploitation or destruction of Florida native plant populations."
The observed species fall into this category. Their distribution on site is
restricted primarily to the periphery and wooded strips along the Peace River,
Bowlegs Creek and tributaries. Much of this habitat has been severely de-
graded by cattle grazing and man-related activities such as drainage of
3-129
-------
wetlands, controlled burning, and clearing for agricultural and forestry inter-
ests, thus reducing the value of these areas for the listed species. None are
presently in danger of extinction from the state.
Animal species listed below have been classified as endangered, threatened, or
of special concern by the Florida Game and Fresh Water Fish Commission.
Wood Stork - Endangered
Florida Sandhill Crane - Threatened
Sherman's Fox Squirrel - Special Concern
Gopher Tortoise - Special Concern
Florida Burrowing Owl - Special Concern
Little Blue Heron - Special Concern
Snowy Egret - Special Concern
Louisiana Heron - Special Concern.
Wood Stork: One sighting of a wood stork occurred during the field studies.
xThe cypress swamp was checked for nests, and none were found. The site
habitat for this species is limited and of poor quality. It is likely that
this sighting was non-characteristic, and the wood stork sighted was a visitor
to the site.
Florida Sandhill Crane: This species was observed at four locations on the
mine site. They are thought to be residents since the site contains pasture
and freshwater marsh, their preferred habitat.
Sherman's Fox Squirrel: Two Sherman's fox squirrels were observed on site in
uncharacteristic habitat. The small size and poor quality of longleaf pine
habitats on site suggest that the fox squirrel population is small.
Gopher Tortoise: This species was observed on site. The gopher tortoise
occurs in habitats on xeric, sandy soils; however, much of this land is now in
pasture and there are only a very few active burrows left.
Florida Burrowing Owl: The Florida burrowing owl was observed on the proposed
mine site. Almost all pastures on site with dry, sandy soil have active owl
burrows. In one pasture 12 active owl burrows were found.
3-130
-------
Little Blue Heron, Snowy tgret, and Louisiana Heron: These species were ob-
served on the proposed mine site. All sightings included a low number of indi-
viduals and no rookery areas were found. Their wetland habitats on the site
are either small or of poor quality.
3.6.1.2.7 Wetlands Classifications
Federal jurisdiction over wetlands is based primarily on Section 404 of the
Clean Water Act of 1977 (33 USC, 1344), formerly known as the Federal Water
Pollution Control Act, in which wetlands are defined, their uses and values
described and a basis for regulation presented. Subsequently, vegetation
lists were developed to assist in defining wetlands (U.S. Army Corps of Engi-
neers, 1978), and a functional and physical approach to wetland classification
has been developed (Cowardan et al., 1977). Reppert et al. (1979) provide a
technical concept and procedure for evaluation of wetlands based on the re-
quirements of the Clean Water Act. The procedure emphasizes ecosystem func-
tional criteria and structural characteristics rather than the presence of
certain species as criteria. This provides a basin-wide assessment among
widely varying wetland types and allows an evaluation of a particular site as
a unit within a larger system.
Areawide EIS: In the Final Areawide Environmental Impact Statement for the
Central Florida Phosphate Industry (EPA, 1978) the U.S. Environmental Protec-
tion Agency established a wetlands categorization system to serve as a guide-
line for regulating the mining and reclamation of wetlands. This system en-
tailed the assignment of wetlands on new source mine sites into one of three
categories:
Category 1 Preserve and Protect: Wetlands that must be preserved and pro-
tected without disruption. Wetlands within and contiguous to rivers and
streams having an average annual flow exceeding 5 cubic feet per second as
well as other specific wetlands determined to serve essential environmental
functions, including water quality. (These are wetlands that provide an
essential synergistic support to the ecosystem and that would have an
unacceptable adverse impact if they were altered, modified, or destroyed.)
This generally includes cypress swamps, swamp forests, wet prairies, and
certain freshwater marshes.
3-131
-------
Category 2 ~ Mine and Restore Equivalent Acreage: Wetlands that should be
restored as wetlands to perform useful wetland functions. This also includes
certain isolated noncategory wetlands that serve a primary function or several
minor functions that may be maintained through proper restoration.
Category 3 Mine With No Restoration of Wetlands: Wetlands that would not
have to be restored as wetlands. These are isolated and normally intermittent
in nature, have less significant hydrological functions than Category 2, and
minimal life-support value.
Site Evaluation: The wetlands identified on the proposed South Fort Meade
Mine Site have been defined and evaluated according to the requirements of
Section 404 of the Clean Water Act and then categorized according to the
guidelines presented in the Areawide EIS (EPA, 1978).
The Reppert et al.{1979) procedure supplemented with a Delphi technique for
weighting criteria was utilized to conduct a site-specific determination of
wetlands and their functional significance on the proposed site. The Delphi
technique and criteria weighting were employed because it was considered
necessary to involve all key agency decision-makers in assigning weightings to
wetland values and because the basic methodology assumed all wetland values
criteria were equally important. Polling of the key decision-makers at an
early stage in the evaluation process not only provided a relative ranking of
wetland valuation criteria but also produced a consensus position for probable
values of wetland units on the site. Site-specific conditions were used to
assist in establishing the baseline from which the evaluation and categori-
zation were made. The results of the wetlands study are summarized in Figure
3.6-B and in the following subsections. The complete report of the study en-
titled "South Fort Meade Mine Tributary Functional Analysis to Support an
Assignment of EPA Wetland Categories" is available in limited supply from EPA,
Region IV, EIS Branch.
Category 1 Wetlands: For Bowlegs Creek and the Peace River, the 5 cfs flow
points occur upstream of the Mobil South Fort Meade Mine site. Therefore, wet-
lands within the areas contiguous to these systems were designated Category 1
to be protected from mining. These wetlands were limited in extent because of
3-132
-------
WETLAND DELINEATION MAP
PROPOSED SOUTH FORT MEADE MWE SITE
MOBL CHEMICAL COMPANY
w^vj ysf-'.V' ffi u\ - \'-*Ť.. \) ft _.
'"-
-------
local topography (steep banks) but are believed to meet or exceed both the EPA
(1978) and Army Corps pf Engineers (Reppert et al., 1979) criteria for
valuable and important wetlands within the context of Section 404.
Tributaries to these two flowing systems had less than 5 cfs as a mean annual
flow at their mouths. The species similarity of the tributaries and receiving
systems was low. Interchange of species between the systems was minimal, and
contribution of materials and species from the smaller tributaries to the much
larger river and creek systems was shown to be minimal. Zero and very low
flow conditions were usual occurrences for the tributaries. Therefore, the
break between Category 1 and Category 2 systems was placed at the flood
backwater point indicated by the elevation of the water line on trees along
the Peace River and Bowlegs Creek.
Category 1 depression wetlands in the plateau included a large cypress dome
near the eastern boundary of the site. This 75-acre dome is open in the
center with several strata of vegetation and provides some fish and wildlife
habitat.
Category 2 Wetlands: Category 2 wetlands include the small tributaries whose
primary function is to convey excess flow from the site interior to the Peace
River and Bowlegs Creek, and the smaller seasonally flooded plateau depression
wetland units.
The small tributaries contributing to the Peace River and Bowlegs Creek from
the property have less than 5 cfs annual average flow. They exhibit steep
channel gradients and are dependent on low volume seepage for minimal flow
maintenance. The biotic similarity, as based on benthic macroinvertebrates,
is low between the tributaries and the Peace River and Bowlegs Creek. Flood-
ing and ordinary backwater flow from the Peace River and Bowlegs Creek into
these tributaries are restricted to the immediate vicinity of the tributary
mouths. Lateral spreading or tributary flooding is severely restricted by the
narrow deep channel incisions above the Peace River and Bowlegs Creek flood-
plains. The incisions effectively isolate the floodway wetland vegetation
from the throughput of waters and further minimize the ability of the wetlands
3-134
-------
to provide water retention and storage, habitat and food chain production func-
tions as an internal capability or in support of downstream units.
Category 2 depression units do not support a wide range of aquatic animal
species because of their shallow seasonal flooding and isolation from stocks
needed to recolonize the area when flooding occurs. Organic or peaty mater-
ials accumulate slightly or not at all in the depressions, although the soil
may have a relatively high organic content. The wetland characteristics and
vegetation in many of these units are maintained by adequate soil moisture
conditions rather than by the sustained presence of surface water which would
result in great functional importance of the units. This combination of
factors results in lessened aquatic system value.
Category 3 Wetlands: These small depression wetlands are less than 5 acres
each in size, typically are flooded for a shorter period than larger units, do
not accumulate organic or peat layers because of limited water retention, and
develop aquatic characteristics and values to a lesser degree than do more
permanent units. Their connections to other units are minimal, and their
ability to provide materials and services to other systems is correspondingly
small. These units usually are isolated and scattered over the plateau, and
are viewed as small, very shallow depressions with patches of herbaceous wet-
land species. Cattle grazing and periodic burning serve to further limit
their development or alter their character and therefore minimize their value
as wetlands.
3.6.2 ENVIRONMENTAL CONSEQUENCES OF THE ALTERNATIVES
3.6.2.1 The No Action Alternative
Under the no action alternative, terrestrial biological resources should
remain basically the same as described in Section 3.6.1. Pasture would remain
the major land use, and the vegetation on site would continue to be slowly
altered by continued cattle foraging. Aquatic biological resources would be
expected to remain the same as described in Section 3.6.1. However, natural
succession would gradually modify habitats. Long-term changes in. precipi-
tation patterns could alter hydroperiods of wetlands and other aquatic
habitats, resulting in possible shifts in plant and animal communities.
3-135
-------
3.6.2.2 The Action Alternatives Including The Proposed Action
3.6.2.2.1 Mining Method Alternatives
Dragline (Mobil's Proposed Action); Biological resources on the South Fort
Meade site would be affected by activities associated with the proposed action
of dragline mining. These activities include clearing the land of vegetation,
excavation of overburden and matrix, and construction of roads and other facil-
ities to support the mining operations. Approximately 93 percent of the site
(15,194 acres) would be disturbed over the life of the proposed mine. The
disturbed and undisturbed acreages, by land use and cover type, are given in
Table 3.6-2.
Land Communities: The seven major types of land communities occupy 86 percent
(14,004 acres) of the total acreage of the site. Of this, 93.2 percent of the
land communities (13,045 acres) will be disturbed during the life of the mine.
The vegetation in these habitat types will be harvested and/or eliminated.
Disturbed Undisturbed Percent
Type Acreage Acreage Disturbed
Coniferous Forest 3,231 182
Hardwood Forest 1,140 664
Mixed Forest 121 5
Planted Forest 340 0
Cropland/Pastures 7,608 108
Clearcut 39 0
Citrus 566 0
Total 13,045 959 93.2
Sequential clearing of 50-acre parcels in front of each dragline would allow
migration of larger and more motile fauna (such as the racoon, river otter,
and birds) away from active mining areas to adjacent habitats. The adjacent
habitat is probably at carrying capacity for populations of larger fauna, and
the increases in population due to migration could result in more predation
and disease and a decrease in reproduction. Populations could eventually
stabilize with a resulting net loss in faunal resources. Some of the smaller
and less motile species (such as amphibians, mice, and shrews) would be lost;
however, many of these species are highly adaptable to habitats created during
the mining process and reclamation.
3-136
-------
TABLE 3.6-2..
DISTURBED AND UNDISTURBED ACREAGE BY LAND USE AND COVER TYPE
I
t
CO
Symbol
111
194
211
212
213
231
4111
4121
4221
4222
4223
4224
431
4411
4412
4413
451
531
560
563
6111
6211
6212
6213
6214
6215
6221
6222
6411
6412
Land Use 4
Cover Type
Urban, single unit, low density
Abandoned mine piles
Row crops
Field crops
Improved pasture
Oranqe groves
Cutover flatwoods, palmetto range
Cutover longleaf pine/sandhill oaks
Live oak, mixed understory
Live oak, bahia understory
Upland mcsic
Transition mesic (bottomland
hardwoods)
Mixed forest
Planted pine - no ground vegetation
Planted pine - bahia ground cover
Planted pine - flatwoods understory
Clearcut bayhead
Unvegetated reservoirs
Other water areas
Cattle water ponds
Pond cypress, isolated
Gum-maple swamp
Bayhead
Bay strand
Myrtle thicket
Mixed hardwood swamp
Disturbed gum-maple swamp
Disturbed bayhead
Isolated upland depressions
Uetland depressions
TOTAL
Disturbed
Acreage
4
214
sin
30
6.768
S66
e 3,207
aks 24
106
11
626
397
121
ion 17
r 204
ory 118
39
3
0
6
3
163
410
23
15
198
8
84
869
150
15,194
Undisturbed
Acreage
0
0
0
0
108
0
182
0
3
107
34
520
5
0
0
0
0
0
3
0
75
22
8
0
6
0
0
0
14
7
1,094
Percent
Disturbed
100
100
100
100
98
100
95
100
97
9
95
43
96
100
100
100
100
100
0
100
4
88
98
100
71
100
100
100
98
96
93
SOURCE: STUDY DATA
-------
Land-Water Interface Communities: Three major land-water interface communi-
ties occupy approximately 12.6 percent (2,054 acres) of the proposed mine
site. During the life of the mine 93.6 percent (1,923 acres) will be
disturbed.
Disturbed Undisturbed Percent
Type Acreage Acreages Disturbed
Wetland Coniferous Forest 3 75 3.8
Wetland Hardwood Forest 901 36 96.2
Non-Forested, Vegetated Wetlands 1.019 21 98.0
Total 1,923 132 93.6
The preserved wetlands (132 acres) are primarily the large (75 acre) cypress
dome on the eastern edge of the property and those wetlands within the buffer
strips along the Peace River (450 feet each side) and Bowlegs Creek (300 feet
each side) as shown in Figure 3.6-B.
Water Communities: Impacts on the aquatic ecosystems from dragline mining
include eliminating 9 of the 12 acres (75 percent) of the ponds on site.
Additionally, dragline mining will destroy aquatic habitat by eliminating
60,000 linear feet of stream channel originating on the site. The Peace River
and Bowlegs Creek would not be mined; however, alteration of stream flow would
result from mining adjacent areas. In sections of the on-site tributaries not
subject to mining, aquatic organisms may be affected by the mining of the rest
of the tributary. The effects should be minimal since the protected areas are
backwaters of the Peace River and Bowlegs Creek, the connection to which would
allow fish and invertebrates the opportunity to move from the tributaries.
To gain access to mining parcels north of Bowlegs Creek, a dragline cross-
ing would be located at an existing ford (Figure 2.1-A). Bowlegs Creek is
scheduled to be crossed in 1999 and again in 2002 at the same ford. Woody
vegetation in the corridor to the crossing would be cleared to about twice
3-138
-------
the width of the dragline (approximately 2 acres), and a culvert would be
placed in the creek with earth backfilled around it. After each crossing,
grass cover would be established to prevent erosion and runoff in the cleared
corridor. After the second crossing in 2002, the culvert would be removed and
the stream channel would be re-established. Tree species characteristic of
wetlands would supplement the grass cover in the corridor.
Construction of the dragline crossing at Bowlegs Creek would affect downstream
aquatic resources due to increased turbidity levels. High turbidity (sus-
pended solids) effects on aquatic organisms would result from sedimentation,
reduc-tion of light penetration and availability as a surface for growth of
micro-organisms. Increased turbidity would be temporary at the crossing area
and the short-term duration (several days) should not present a major impact.
Migratory Wildlife and Game Species: Because of habitat degradation and
absence of large open water bodies, few migratory or game species occur on the
site. The area is not managed for hunting; the land is privately owned and
hunting is restricted. There is no commercial fishing on site, although there
is sport fishing on Bowlegs Creek and the Peace River. Creation of large open
water areas for clay settling during waste disposal would provide short-term
habitat for migratory waterfowl. Creation of wetlands in larger units (over
100 acres) or acreage blocks as a result of reclamation would benefit aquatic
species. Terrestrial species would benefit from the creation of more mixed
forest. The primary land use of the reclamation plan is agriculturally
oriented with some benefits to terrestrial game species.
Agricultural and Forestry Resources: Existing agricultural resources, in-
cluding pasture, cropland and citrus, would be virtually eliminated during
mining of the South Fort Meade Mine site. Of the 8,282 acres of agricultural
land, 108 acres of improved pasture would be left undisturbed (Table 3.6-2).
The 810 acres of row crops and 30 acres of field crops would be removed during
mining. AIT of the 566 acres of citrus on site would be disturbed, including
446 acres of citrus designated by the Soil Conservation Service (SCS) as
unique citrus areas.
Forestry resources (planted pine) presently occupy approximately 340 acres,
representing the equivalent of 4,153 cords of wood. All planted pine acreage
3-139
-------
would be disturbed by mining. The wood would be harvested before the areas
are mined.
Federal Rare and Endangered Species: No Federally protected plants were found
on site. Regarding animal species, there is no designated critical habitat
within the boundaries of the South Fort Meade Mine site. The U.S. Fish and
Wildlife Service (December 18, 1980) supplied EPA with the following listing
of species believed to be present in the area:
Bald Eagle - Endangered
Red-Cockaded Woodpecker - Endangered
Eastern Indigo Snake - Threatened
American Alligator - Threatened.
The southern bald eagle was reported to have been observed on site but the
sighting could not be confirmed. However, an eagle nest was recently found
outside the northeastern property boundary as shown on Figure 7.3-A. The
proposed mine site may be used by the bald eagle for foraging, especially
during the feeding of the young. Although the lands preserved along the
streams may provide nesting habitat, the proposed mining may eliminate
potential feeding areas.
The red-cockaded woodpecker is not believed to exist on the site and
consequently should not be adversely affected by the project.
The eastern indigo snake was observed primarily in the wooded strips along the
Peace River and Bowlegs Creek. An effect of preserving a 450-foot buffer
strip along the Peace River and a 300-foot buffer from each bank along Bowlegs
Creek would be to minimize impacts on the indigo snake populations occurring
in these areas. The individuals seen along the tributaries on the mine site
would be disturbed by mining, but the slow pace of the land clearing and min-
ing would provide an opportunity for the snakes to evacuate. The mining of
the mesic environments and other habitats of potential occurrence of this
species would result in destruction of available habitat for this species
which could reduce populations.
3-140
-------
Alligators inhabit Bowlegs Creek, the Peace River and some wetlands on the
site. Bowlegs Creek, the Peace River and the lower lengths of their tribu-
taries would be preserved as previously discussed. Many of the other small
water areas would be mined. The total acreage of wetlands after mining would
be slightly more than the existing and habitat for this species would be
increased after reclamation. Ponds, ditches, pools and settling basins would
provide temporary habitat during mining for the alligators. The land clearing
operation would be gradual enough to allow the alligators to move out of the
areas to be disturbed. The development of the proposed mine would not
significantly affect the alligator population.
State Rare and Endangered Species: Twenty-four protected plants listed as
endangered, threatened, or of special concern under Florida Statute 581.185
(Preservation of Native Flora of Florida) were observed on the proposed mine
site. Their distribution on site is restricted primarily to the periphery and
wooded strips along the Peace River, Bowlegs Creek, and portions of the tribu-
taries which are within the designated preservation areas (Figure 3.6-B).
Populations of species on other portions of the tributaries scheduled for
mining and those occurring on scattered locations would be eliminated. The
impacts of the regional populations of these species would be minimal,
however, as none are presently in danger of elimination from the state.
Animal species classified as endangered, threatened, or of special concern by
the Florida Game and Fresh Water Fish Commission are listed below.
Wood Stork - Endangered
Florida Sandhill Crane - Threatened
Sherman's Fox Squirrel - Special Concern
Gopher Tortoise - Special Concern
Florida Burrowing Owl - Special Concern
Little Blue Heron - Special Concern
Snowy Egret - Special Concern
Louisiana Heron - Special Concern.
The wood stork habitat on site is small in extent and of poor quality. This
species is not characteristic to the site and, therefore, should not be
affected by the development of the proposed mine.
3-141
-------
The Florida sandhill crane was observed at four locations on the mine site.
They are thought to be residents since the site contains pasture and fresh-
water marsh, their preferred habitat. Mining would destroy their preferred
habitat; however, reclamation would restore both freshwater marsh and pasture.
Two Sherman's fox squirrels were observed on site in uncharacteristic habitat.
The small size and poor quality of longleaf pine habitats on site suggest that
the fox squirrel population is small. Mining would eliminate this species'
habitat on the project site.
The gopher tortoise was observed on site and occurs in habitats on xeric,
sandy soils; however, much of this land is now in pasture and there are only a
very few active burrows left. Mining would eliminate this species from the
site; however, it is not expected that mining would have a significant effect
on the gopher tortoise populations of the region.
The Florida burrowing owl was observed on the proposed mine site. Almost all
pastures on site with dry, sandy soil have active owl burrows. In one pasture
12 active owl burrows were found. Mining would eliminate almost all (98.6
percent) of the pasture/cropland on site. Reclamation would result in
restoration of pasture; however, soils may not be suitable for nesting of this
species.
The little blue heron, snowy egret, and Louisiana heron were observed on the
proposed mine site. All sightings included a low number of individuals and no
rookery areas were found. Their wetland habitats on the site are either small
or of poor quality, limiting viable population levels of these species on
site. Mining will eliminate 93.6 percent of the wetland communities on site.
Since there are no known nesting colonies on site, mining would have little
impact on regional populations of these species.
Wetlands: Site-specific conditions were used to assist in evaluating the
functional value of the wetlands present on the site. The study, "South Fort
Meade Mine Tributary Functional Analysis to Support an Assignment of EPA
Wetland Categories", indicated that the interior wetland units have minimal
aquatic system value and regional significance. Wetland areas on the property
3-142
-------
were classified as either Category 1 (preserve and protect), Category 2 (mine
and restore with equivalent acreage) or Category 3 (mine with no restoration
to wetlands).
Construction of the proposed mine would result in the loss and protection of
the following acreages of each of the wetland categories.
Category 1
Category 2
Category 3
Acres
Existing
84
1,601
370
Acres
Disturbed
0
1,553
370
Acres
Protected
84
48
0
Percent
Protected
100
3
0
Total 2,055 1,923 132 6
Approximately 1,923 acres designated as wetlands (94 percent of total wetland
acreage) wold be eliminated by mining (Table 3.6-2). The preserved wetlands
(132 acres) are primarily the large (75 acre) cypress dome on the eastern edge
of the property and wetland areas within buffer strips along the Peace River
(450 feet each side) and Bowlegs Creek (300 feet each side), shown in Figure
3.6-B.
Bucket Wheel : The bucket wheel mining method would disturb the land surface
in much the same way as the dragline method. Impacts on the biological re-
sources resulting from bucketwheel mining would be essentially the same as
those described for dragline mining.
Dredge: The dredge mining method requires clearing large tracts of land to
provide dredge basins, resulting in a larger habitat loss at one time than the
dragline mining method. Larger amounts of aquatic habitat are created, but
the dredge basin pools are limited in their usefulness for many aquatic spe-
cies, with the exception of migratory waterfowl due to small literal zones.
The impacts associated with dragline mining would also be expected with dredge
mining. Additional impacts associated with dredging could result from dredge
basin dike failure and subsequent release of turbid water into nearby surface
water. This could adversely affect aquatic organisms by increasing suspended
solids levels and other pollutants. Crossing Bowlegs Creek would be accom-
plished by transportation of the dredge along existing roads with minimal im-
pact on the site's biological resources.
3-143
-------
3.6.2.2.2 Matrix Transfer Alternatives
Pipeline (Mobil's Proposed Action): A pipeline method of transfer requires
clearing corridors (approximately 12 feet wide) from the mining area to the
plant facilities. Impacts resulting from clearing, construction and main-
tenance include habitat destruction, disruption or isolation of habitat units
cut by the corridor, and altered migration and dispersal patterns of fauna.
These impacts would probably be short-term because the pipeline corridor
locations are changed as mining proceeds, and are usually maintained on
disturbed lands which would require minimal clearing.
Mining on the north side of Bowlegs Creek would require a matrix slurry pipe-
line stream crossing of Bowlegs Creek during a four-year period of the mine
life. If a break or leak occurred in the transfer line at the stream cross-
ing, suspended solids, nutrients, sediment, and other contaminants would be
increased and would damage aquatic and wetland ecosystems for a short time
until corrective clean-up actions were taken. The use of valves and double-
walled pipe as described in Mobil's proposed action would minimize the
potential for a spill occurrence at the stream crossing.
Conveyor Belt: Impacts resulting from corridor routing of the conveyor belt
system would be similar to those described for the pipeline system. Spills
from the conveyor system would be more confined due to the solid nature of the
material and would have less effect on terrestrial and aquatic ecosystems.
Truck: Roads for truck transfer of the matrix would have impacts similar to
those discussed for the pipeline system, although the corridor (road) would be
larger and more permanent than that for the pipeline. Although the potential
for spills or leaks is less for this matrix transfer alternative, truck trans-
fer would result in increased noise, fugitive dust and truck emissions, all of
which could disrupt wildlife in the immediately adjacent area.
3.6.2.2.3 Waste Disposal Alternatives
Conventional Clay Settling Case (Mobil's Proposed Action): A primary concern
with above-grade settling basins is the potential for dike failure. In the
event of a failure, large volumes of clay could be discharged into Bowlegs
3-144
-------
Creek and/or the Peace River, increasing turbidity, destroying natural biolog-
ical communities, depositing sediments, and raising the concentrations of
sulfates, fluorides, and total dissolved solids. The physical action of a
spill would destroy vegetation and fauna at the spill site, while downstream
aquatic organisms could be lost due to water quality degradation and excessive
sedimentation. Studies of spills (Ware, 1969) indicate that approximately 90
percent of fish and most of the macroinvertebrates (except oligochaetes and
chironomid larvae) in the spill zone were killed by blanketing from sediments.
However, both investigators judged stream recovery as rapid. Terrestrial
ecosystems within a spill zone would be damaged by flooding and destruction of
ground cover and by the loss of less motile fauna (such as amphibians, mice
and shrews) which would be smothered by the clay wastes.
During the life of the mine, approximately 8,170 acres (Table 3.6-3) of above-
grade clay settling basins would be constructed with dike heights ranging from
25 to 45 feet and averaging 38.7 feet (Table 2.5-2). The worst case situation
for a dike failure would be when the greatest amount of active above-grade
settling acreage is in service. For the conventional clay settling case this
occurs in mine years 12 through 14 when five basins (CS-4, CS-5, CS-6, CS-7
and CS-8) covering 2,760 acres are all active, operating in a flow-through
settling mode (Figure 2.5-B and Table 2.5-3). Should a dam failure happen at
this time, most of the clays released would probably flow into Bowlegs Creek
or the Peace River because of the natural topography of the site. It is
doubtful that any off-site property would be affected except for the roadways
that pass through the site. The primary effect would be on the on-site and
downstream sections of the Peace River and Bowlegs Creek. Smaller spills
could occur from other isolated clay settling areas. The primary effect would
still be degradation of water quality in the Peace River or Bowlegs Creek.
The technology used to construct the settling basin dikes has improved substan-
tially during the past decade, reducing the likelihood of a dike failure.
Thorough investigations of foundation and soil conditions at the location of
the proposed dikes would be conducted on the South Fort Meade site prior to
design and construction. The dikes would be continuously inspected and moni-
tored during the active life of the settling basins. Mobil would comply with
3-145
-------
TABLE 3.6-3
WASTE DISPOSAL ACREAGE
LAW TYPE
CONVENTIONAL CASE
SAND/CLAY CAP CASE SAND/CLAY H1X CASE OVERBURDEN/CLAY MIX CASE
Clay Settling (no cap) 6.6B1
Clay capped with Sand Tailings 1,4Ť9
Clay capped with Overburden
Clay capped with Sand/Clay
Mix (4:1)
V Clay capped with Sand/Clay
Ł Mix (2:1)
Sand/Clay Mix or
Overburden/Clay Mix (2:1)
Overburden Fill Plant Site
and Graded Spoil 477
Sand Tailings Capped with
Overburden 5,034
Water (Below-grade Clay
Settling Areas) 1,513
Total 15,194
1,642
590
7,580
3,185 2,847
3.512 5,492
432 1,740 1,740
5,079 3,020 3,020
1,513 2,095 2,095
15,194 15,194 15,194
SOURCE: STUDY DATA
-------
the regulations for design, construction and maintenance of earthen dams estab-
lished by the Florida Department of Environmental Regulation (FAC Chapter
17-9).
The active settling areas would provide interim aquatic habitats. These areas
would support common marsh species as volunteer plants invade them and would
provide food sources for wildlife.
Sand/Clay Cap Case: The sand/clay cap waste disposal case has dike configura-
tions similar to those of the conventional clay settling case; however, the
average dike height is decreased two feet (Figure 2.5-C, Table 2.5-5). Flow
through settling cannot be practiced with this waste disposal case; therefore,
the amount of active above-grade settling acreage is reduced. Basin CS-3
would be used during the life of the mine as a dredge basin and would be
filled and emptied several times during the mining activities. The greatest
amount of active above-grade settling occurs in mine years 17 through 19 when
CS-3 and CS-10, with a maximum area of 1,860 acres, are active (Table 2.5-6).
The potential for a dike failure occurring is decreased for the sand/clay cap
waste disposal case compared to the proposed action because of the reduced
active settling acreage (less than 1,860 acres compared to 2,760 acres) (Table
3.6-3). Should a spill event occur, the effect on biological resources would
be similar to that described for the proposed action except that the volume of
clay that could potentially spill would be reduced by 21 percent for the sand/
clay cap waste disposal case compared to the conventional clay settling case.
This reduction results from the lower average clay fill height with the
sand/clay cap case (27 feet versus 34 feet).
Interim aquatic habitat provided by clay settling areas would be less for the
sand/clay cap case than for the proposed conventional case because of the re-
duced active settling acreage.
Sand/Clay Mix Case: The sand/clay mix waste disposal case has 4,827 acres
(Table 3.6-3) of above-grade clay settling basins with dike heights from 40 to
48 feet, and 3,352 acres of above-grade sand/clay mix basins with dike heights
from 20 to 37 feet (Tables 2.5-8 and 2.5-10). The 4,827 acres of above-grade
clay settling basins would be operated in a manner comparable to the sand/clay
3-147
-------
cap case and could not utilize flow through settling since these areas will be
dewatered quickly in order to cap them with sand/clay mix. Two dredge basins
would be constructed to provide clay for sand/clay cap material as well as
sand/clay mix for the 3,352 acres of mix basins. The maximum amount of active
settling acreage (2,450 acres) is between that of the conventional clay set-
tling case (2,760 acres) and the sand/clay cap case (1,860 acres). Therefore,
the potential for a dike failure occurring is greater than the sand/clay cap
case but less than the conventional clay settling case.
The sand/clay mix case has two types of above-grade basins: sand/clay mix and
conventional clay settling. The sand/clay mix material would consolidate more
rapidly and would have higher density than the clay wastes impounded sepa-
rately. This increase in density and consolidation would result in a decrease
in flow characteristics of the mix material should a dike failure occur from
one of the mix basins. Therefore, the volume of a sand/clay mix spill would
be less than that expected from a clay settling basin spill. If a dike fail-
ure occurred from one of the clay settling basins the effect would depend on
the quantity of material released but would be similar to that described under
the conventional clay settling case.
The sand/clay mix case would have less active settling acreage resulting in
less interim aquatic habitat than would be available with the proposed
conventional disposal case.
Overburden Mix Case: The configuration, size and active settling acreage of
above-grade basins with the overburden mix waste disposal case are similar to
the sand/clay mix case; however, the extent of sand/clay mix impoundments
would be increased to 7,670 acres. The average dam height would be 38 feet.
The potential for a dike failure and resultant effect on surface water streams
would be comparable to those described for the sand/clay mix basins under the
sand/clay mix case.
3.6.2.2.4 Reclamation Alternatives
Conventional Clay Settling Plan (Mobil's Proposed Action): Mobil's proposed
reclamation plan for the 15,194 acres disturbed by mining is illustrated in
Figure 2.1-1. Improved pasture (11,413 acres) would be developed on above-
grade settling areas and sand tailings fill areas with overburden cap. Upland
3-148
-------
mixed forest (1,271 acres), planted pine (453 acres) and forested stream
channel (277 acres) would be developed in sand tailings fill areas with over-
burden cap. Freshwater swamp (478 acres) would be developed in above-grade
clay settling areas, and freshwater marsh (1,302 acres) would be developed in
below-grade clay settling areas capped with overburden.
With completion of reclamation, the total wetland acreage would be approx-
imately 93 percent of that existing on the site; the combined forested stream
channel acreage and wetland acreage would exceed the existing wetland acreage
by approximately seven percent (Table 3.6-4). However, there would be a shift
in the proportion of wetland type from freshwater swamp toward freshwater
marshes. Specifically, reclamation would decrease freshwater swamp acreage by
426 acres (from 1,015 to 589) and increase freshwater marsh acreage by 283
acres (from 1,040 to 1,323). Reclaimed upland mixed forests would serve to
expand the forested zones along the Peace River and Bowlegs Creek and provide
dense forest stands. Final land use and cover for the conventional reclama-
tion case would be predominately agriculture (Table 3.6-4), which is consis-
tent with the present land use on the site. More specifically, land use is
proposed as improved pasture with no provision for row crops, field crops, or
citrus. Planted pine acreage would be increased from 339 to 453 acres.
The conventional settling case does not favor establishment of trees except in
sand tailings, overburden, and cap areas. Waste clay disposal areas (no cap
or mix) are best suited to perennial forage crops or pasture. The above-grade
clay waste areas capped with sand would be reclaimed as pasture, but would
also contain a mixture of hardwood and coniferous tree species. All refores-
tation would be done with a mixture of native tree species such as longleaf
pine, live oak, and dogwood on well-drained sites and water oak, sweet gum,
and slash pine on wetter sites. Planting density would be 400 trees/acre for
upland reforestation.
At various locations thickets would be planted to provide escape cover for
animals and generally increase diversity of plant cover. Stream channel
reclamation would be done in sand tailings or overburden fill areas, and a
normal water level channel and/or associated floodplain created. Shallow
pools would be maintained in the created stream channels to provide permanent
water supply for wildlife.
3-149
-------
TABLE 3.6-4
ACREAGES BY LAND USE AND COVER CLASSIFICATIONS FOR RECLAMATION PLANS
CO
1
en
O
Reclamation
Case
Existing
Conventional
(Proposed Action)
Keel a lined
Undisturbed
TOTAL
Reclaimed
Undisturbed
TOTAL
Sand/Clay Mix
Reclaimed
Undisturbed
TOTAL
Overburden Mix
Agricultural Cutover Upland Upland Planted
Flatwoods Hardwood Mixed Pine
and Bayhead Forest Forest
8282
11.413
108
11,521
11,003
108
11,111
10,313
108
10.421
Similar
3452 1804 126 339
0 0 1,271 453
182 664 5 0
182 664 1276 453
0 0 1,451 536
182 664 5 0
182 664 1.456 536
0 0 1,826 431
182 664 5 0
182 664 1.831 431
to sand/clay mix case
Water forested Freshwater Freshwater TOTAL
Areas Stream Swamp Marsh
Channel**
12 ** 1,015 1,040 16,288*
0 277 478 1.302 15,194
3 0 111 21 1,094
3 277 589 1,323 16,288
0 279 504 1.421 15,194
3 0 111 21 1,094
3 279 615 1,442 16.288
0 263 746 1.616 15,194
3 0 111 21 1,094
3 263 867 1,636 16,288
* Includes 4 acres of residential land and 214 acres of abandoned mine.
* This term is not used in describing the existing (premininy) case. For the reclamation cases, this term applies to the
200-ft wide reforested area, associated with the 60,000 lineal feet of recreated stream channels.
SOURCE: STUDY DATA
-------
Short-term adverse reclamation impacts would result from recontouring, vegeta-
tion planting and construction of stream channels. Capping of settling areas
would result in the loss of vegetation and wildlife established on clay set-
tling and tailings fill areas. Construction activities would produce in-
creased noise levels, fugitive dust and potential erosion problems, possibly
affecting adjacent protected areas on Bowlegs Creek and the Peace River.
Removal of native volunteer vegetation prior to replanting according to the
desired vegetation schemes would result in the loss of large areas of interim
habitat. However, these impacts are minor in terms of long-term reclamation
goals.
Reconstruction of stream channels to approximate former drainage patterns on
site could potentially create turbidity and sedimentation in the Peace River
and Bowlegs Creek. The proposed action would minimize this impact by allowing
complete vegetation to be established in the channels for filtering and reduc-
ing sediment loads and turbidity before connection with the downstream chan-
nel. Additionally, establishment of shallow depressions, where drainage would
exist in the reclaimed waste disposal areas, would provide a filtering effect
once vegetation is established. Establishment of streams or tributaries would
provide drainage for surface water runoff from the reclaimed landforms, as
well as avenues of dispersal for animals and detrital materials.
Sand/Clay Cap Plan: The sand/clay cap reclamation plan would reclaim the
15,194-acre disturbed area as follows: improved pasture (11,003 acres) would
be developed in above-grade clay settling areas capped with 4:1 sand/clay mix
and sand tailings fill areas with an overburden cap; upland mixed forest
(1,451 acres), planted pine (536 acres), and forested stream channel (279
acres) would be developed in sand tailings fill areas with an overburden cap;
freshwater swamp (504 acres) would be developed in above-grade clay settling
areas; and freshwater marsh (1,421 acres) would be developed in below-grade
clay settling areas capped with overburden.
The predominant land use for the sand/clay cap reclamation would still be
agriculture (Table 3.6-4). However, the areas capped with a sand/clay mix
(4:1 ratio) are less limited in their agricultural potential than either the
uncapped conventional clay settling areas or the 2:1 sand/clay mix areas (see
3-151
-------
Section 3.2 Geology and Soils). That is to say, although the proposed land
use in each case is improved pasture, the surface soils composed of the 4:1
sand/clay mix should also allow the planting of field and row crops. More
wetland acreage (8 percent) is proposed for this reclamation plan than for the
conventional clay settling plan. Additionally, more upland forested areas are
proposed for reclamation due to the suitability for shrub and tree planting of
capped clays versus open or no cap on waste clay disposal sites. This would
aid wildlife by committing more acreage to suitable habitat. Reforestation
and revegetation would be the same as for the conventional plan. Stream
channel creation would also be the same as for the conventional plan except
that there would be less alteration of drainage areas from existing patterns.
Sand/Clay Mix Plan: The sand/clay mix reclamation plan would reclaim the
15,194 acre disturbed area as follows: improved pasture (10,313 acres) would
be developed in above-grade sand/clay mix (2:1) areas, clay settling areas,
and sand tailing fill areas capped with overburden; upland mixed forest (1,826
acres), planted pine (431 acres) and forested stream channel (263 acres) would
be developed in sand tailings fill areas with an overburden cap; freshwater
swamp (746 acres) would be developed in above-grade sand/clay mix (2:1) areas,
clay settling areas and below-grade sand/clay mix (2:1) areas; and freshwater
marsh (1,615 acres) would be developed in below-grade clay settling areas
capped with overburden.
The predominant land use of the sand/clay mix case would be agriculture (Table
3.6-4). Soils would be more suitable for planting tree species in this plan
than in the conventional plan. The sand/clay mix reclamation plan would
result in 2,495 acres of upland hardwood and mixed forest being reclaimed, or
28.6 percent more than the conventional settling plan. More wetland acreage
(2,361 acres or 33 percent more) would be reclaimed with the sand/clay mix
plan than with the conventional plan. This would result in more wildlife
habitat for invading and recolonizing animal species than would be available
as a result of the two previously discussed reclamation plans.
Overburden/Clay Mix Plan: The overburden/clay mix reclamation plan would
reclaim the 15,194-acre disturbed area essentially the same as the sand/clay
mix plan. The major difference in impacts on biological resources between the
overburden/clay mix and the sand/clay mix reclamation plans is the potential
3-152
-------
for additional tree planting. The conversion of the 1,642 acres of clay sur-
face soils to sand/clay mix soils creates the potential for additional forest
areas by planting or by natural colonization.
3.6.2.2.5 Water Source Alternatives
Groundwater (Mobil's Proposed Action): No impact on the biological resources
is anticipated from the use of groundwater pumped from the Floridan Aquifer
for the water source. Streams, wetlands, and other surface water resources
would not be affected by this action.
Surface Water: This alternative would require impoundment of portions of
Bowlegs Creek, reducing and possibly eliminating stream flow and materials
contribution from Bowlegs Creek to the Peace River. The floodplain charac-
teristics of Bowlegs Creek to the Peace River and downstream of the impound-
ment would be altered. Impoundment would require clearing of preserved wet-
lands and stream buffer zones for reservoir construction. The surface water
alternative would also result in adverse impacts on the ecological communities
of Bowlegs Creek by eliminating the lotic biological resources now associated
w'ith it. However, an area of open water habitat would be created resulting in
a more stable lentic biological community.
3.6.2.2.6 Plant Siting Alternatives
Gilshey Branch (Mobil's Proposed Action): The biological impacts of locating
the beneficiation plant on the flatlands between Gurr Run and Gilshey Branch
would be confined to removal of the vegetation in the area of construction.
The proposed plant location is in an area now utilized for pasture with mini-
mal plant and animal value; therefore, no significant effects on wildlife are
anticipated from this action.
Other On-Site Locations: Locating the plant near preserved areas on the pro-
perty would increase the potential for adverse impacts, such as dust, noise,
and spillage, on the biological systems. Other on-site locations could have
similar impacts to the proposed action if they were centrally located and had
a pasture cover.
3-153
-------
3.6.2.2.7 Water Discharge Alternatives
Peace River (Mobil's Proposed Action): Discharge from the clear water pool
would occur primarily during extreme rainfall events. Discharge to the Peace
River at average flow could adversely affect aquatic biological resources down-
stream of the discharge point since suspended solids loads at maximum dis-
charge may damage aquatic organisms. However, discharge should occur only
during extreme rainfall events when increased dilution would occur due to the
high flow condition in the receiving stream.
Bowlegs Creek: Flows at maximum discharge would be eight times the annual
mean flow of Bowlegs Creek, resulting in very little potential for dilution of
discharge constituents. The excessive flows could increase turbidity levels
and initiate scouring, both of which would adversely affect aquatic life in
downstream portions of the creek.
3.6.2.2.8 Product Transport Alternatives
Railroad (Mobil's Proposed Action): Land clearing, construction and continual
use of the railroad spur would disturb natural communities along the proposed
route and would disrupt local animal migration and dispersal patterns in habi-
tats adjacent to the route. Noise associated with this transport process
would also adversely affect wildlife in adjacent habitats. The proposed route
requires a crossing of the Peace River. Construction of a bridge would
temporarily affect aquatic biological communities of the Peace River as a
result of sedimentation and turbidity. Construction of bridge approaches
would affect the floodplain vegetation, but impacts should be minimal as there
are no extensive floodplain wetlands associated with the Peace River at the
railroad crossing site.
Truck: Existing road systems would be used to transport products by truck;
therefore, no further impacts from corridor routings are anticipated. Fugi-
tive dust and noise would increase due to increased vehicular use of the road
systems, resulting in adverse impacts to vegetation resources and disturbance
of wildlife in adjacent habitats.
3-154
-------
3.7 HUMAN RESOURCES
3.7.1 THE AFFECTED ENVIRONMENT
3.7.1.1 Demographics and Economics
Both Polk and Hardee Counties experienced growth between the 1970 Census and a
1978 University of Florida estimate. Polk County is estimated to have had a
25 percent increase in population between 1970 and 1978, with the population
growing from 227,222 to 284,388. The population in Polk County is made up of
approximately 80 percent permanent residents, 13 percent transients and 7
percent tourists. Hardee County experienced a slightly smaller increase with
the 1970 Census population of 14,889 growing to an estimated 17,827 in 1978,
representing a 20 percent growth over the eight-year period. Hardee County
has a permanent population of 97 percent, with 1 percent transients and 2
percent tourists.
Polk County experienced a 26 percent increase in housing units between 1960
and 1970, and an additional 20 percent increase between 1970 and 1973. In
1973, there were 97,713 housing units with 2.63 persons per unit. Hardee
County had 6,002 housing units in 1973 with 2.85 persons per unit.
Between 1968 and 1978 Polk County's labor force increased 39 percent from
89,600 to 124,654, with 8.4 percent unemployment in 1977. The labor force in
Hardee County rose from 4,300 in 1967 to 8,438 in 1970; unemployment was 6.1
percent in 1978. An examination of the 1977 average wage and salary income by
industrial division reveals that employees of the mining industry have the
highest average wages. Polk County mining workers received an average annual
wage of $14,613, approximately 46 percent more than the average state-wide
industrial wage of $10,032. Industrial wages averaged $10,023 in Polk County
and $7,980 in Hardee County.
Polk County levies an ad valorem tax on the value of phosphate producing land
and a property tax on the value of land, buildings, and equipment. The state
levies a 10 percent severance tax on the value of a product at the point of
severance. Other taxes which the state levies include a 4 percent sales tax
on materials and supplies, a 5 percent corporate income tax on net income, and
3-155
-------
a motor fuel tax. The Federal government levies an income tax on employee
income and corporate income.
3.7.1.2 Cultural Resources
An archaeological and historic investigation of the South Fort Meade site was
performed by personnel from the Department of Social Services, Florida State
Museum, University of Florida. The investigation consisted of a search of
articles, maps and monographs pertaining to the physical and social develop-
ment of Polk County in general, and Bowling Green, Fort Meade and Wauchula
specifically. In addition, archaeological survey and site reports, the Fort
Meade site file, recent EIS statements, information from private collectors
and local residents, and theoretical and substantive geological, ecological,
and anthropological material were considered.
During the archaeological study, two aboriginal ceramic period sites were
encountered, as were isolated chert flakes and one isolated unifacial scraper.
Two other sites were encountered from post-Archaic periods and were probably
task-specific. One site contained two non-utilized chert flakes and six sand-
tempered, plain sherds. The other site contained two very chalky sherds, nine
non-utilized flakes and one Pinellas point. These isolated sites are thought
to result from single cultural events representing hunting activities. The
survey area appears to have been one of minimal aboriginal activity.
The historic sites encountered during the study were 15 nineteenth and twen-
tieth century homesteads and outbuildings. Two were remnants of a twentieth
century turpentine still and one was a house for black workers employed at the
still. Parts of a tramway built for use by logging companies were also found.
Other remnants of human activity are a result of nineteenth and twentieth
century cash-crop truck farming and mining.
3.7.1.3 Community Services
During the 1978-79 school year, Polk County supported 104 educational facili-
ties consisting of 57 elementary, six middle, 16 junior high, 11 senior high
and two special education schools. The student to teacher ratio was 20.5 to
1. Three vocational-technical schools and nine adult centers were also oper-
ated in Polk County.
3-156
-------
Hardee County had four elementary schools, one junior high school and one high
school with a full time certified staff of 247 in the 1975-76 school year.
The student to teacher ratio for the 1975-76 school year was 19.8 to 1.
Southern Florida College, located in Lakeland, presents opportunities for
higher education.
Fort Meade and Bowling Green, the two closest communities to the site, provide
their residents with sewer services and water supply from groundwater with-
drawals. Recreational facilities in the area consist of 71,210 acres in Polk
County and 771 acres in Hardee County. The local communities support and main-
tain police and fire protection. Hospitals are located in Avon Park, Bartow,
Sebring, and Wauchula.
Electrical energy is supplied to the Polk/Hardee County area by a network of
high-voltage transmission lines interconnecting the load areas of more than 35
power plants owned by various companies. A 35 MW (megawatt) oil-fired power
plant located in Avon Park is owned by the Florida Power Corporation (FPC).
Interconnected power facilities are located in Wauchula, Bartow, and Sebring.
3.7.1.4 Land Use
Agriculture and phosphate mining are the major bases of the economy in the
area of the proposed mine site. Most of the land is rural with large tracts
of agricultural land for cattle grazing and citrus production. Mining occurs
on several tracts near the South Fort Meade site. The many freshwater lakes,
rivers and wildlife habitats contribute to the aesthetics and quality of life
in Polk and Hardee Counties.
Land use in Polk County is predominantly agricultural with citrus groves,
pastures and croplands occupying 42 percent of the land area. Approximately
18 percent of the county has been mined or is being developed for mining by
phosphate companies. Developed land (residential, commercial, industrial,
etc.) accounts for about 10 percent of the land use in Polk County. The other
30 percent is made up of miscellaneous vacant land and water bodies. Only one
percent of Hardee County is developed for urban use, with the majority of the
county, 56 percent, vacant land composed of forests, rangelands and wetlands.
Agricultural uses occupy approximately 43 percent of the land area. Minimal
mining has occurred in Hardee County.
3-157
-------
Approximately 51 percent of the 16,288-acre proposed mine site is used for
agricultural purposes. Of this, about 47 percent of the site is planted in
pasture and crops and 4 percent in citrus groves. A miscellaneous vacant
category includes forest, shrub!and, grassland, rangeland and wetlands, making
up 48 percent of the property. The remaining 1 percent of the property is
covered with water, developed for residential home sites or vacant for power-
line transmission.
The Polk County Comprehensive Plan, prepared in 1979, identifies the following
objective and policies concerning mining areas:
Objective - Mining Areas:
To promote continued mining and processing of minerals on lands now
in active production or being held for that purpose, as a support to
the sound economic base of Polk County.
Policies:
1. Protect, as much as possible, active phosphate mining and
processing areas and reserve lands being held for mining from the
establishment of incompatible land uses in nearby locations.
2. Encourage provision of essential support services and activities
necessary to continued mining productivity in Polk County.
3. Encourage and promote, through existing regulatory control, the
establishment and maintenance of mining and processing procedures
that will minimize the emission of pollutants into the air, soil
and water resources of Polk County.
4. Promote and encourage, through existing regulatory controls, the
preplanning of mining operations to facilitate reclamation of
lands for beneficial uses.
5. Encourage and promote the restoration of previously mined lands
for beneficial uses.
In summary, the future land use plan provides for the mining of lands held in
reserve and the protection of these lands from adjacent incompatible uses.
3.7.1.5 Transportation
Highway vehicles are the primary means of passenger and small freight movement
in both Polk and Hardee Counties (Figure 3.7-A). North of the proposed mine
3-158
-------
TRANSPORTATION FACILITIES AND AVERAGE DAILY TRAFFIC (ADT)
I
I'
tn
POLK_COUNTY_
HAROEE*COUNTY!
MGHLAND3 C
AVON PARK
SOURCES: HAROEE COUNTY
FLORIDA DEPARTMENT OF TRANSPORTATION. BUREAU OF PLANNING
-------
site U.S. Route 98 carries traffic east and west. West of the site U.S. Route
17 provides for north and south flow. On the southern border of the site,
also the Polk/Hardee County line, State Route 664 carries traffic east and
west. Various light and medium duty county roads interconnect these basic
thoroughfares.
The Seaboard Coast Line provides rail freight service in the area with tracks
adjacent to U.S. Route 17 running through Bowling Green and Fort Meade. Most
of the phosphate mined in the area is transported to the Port of Tampa by
railroad. The Port of Tampa provides major dry bulk loading facilities from
which cargo can be shipped to ports in the United States or overseas.
3.7.2 ENVIRONMENTAL CONSEQUENCES OF THE ALTERNATIVES
3.7.2.1 The No Action Alternative
Mobil's existing Fort Meade Mine will cease production during the latter half
of this decade. If Mobil does not develop the South Fort Meade site as a
replacement mine, the contribution to the economy of the area through employ-
ment, tax payments, and other economic factors will decline and eventually
cease with the completion of mining at the Fort Meade facility. The current
175 permanent employees and the $3.7 million payroll (1980 dollars) at the
Fort Meade Mine would be phased out. The $5.5 million in taxes (1980 dollars)
from the Fort Meade Mine would also be lost.
The primary economic effect of the no action alternative would be felt by the
Mobil employees dependent for their jobs and income on the phosphate mining
industry. The loss of secondary income from indirect employment and material
and service suppliers would amount to approximately $50 million (1980 dollars)
per year. Land use would likely remain in its present agricultural state,
although some wetland areas and other miscellaneous land categories on the
site might eventually be developed for pasture or other agricultural land
uses. Property values without the developed mine would decrease relative to
the value for phosphate mining. The no action alternative would reduce
traffic levels on local roads and the Seaboard Coast Line Railroad. Demands
for services such as housing, schools, fire protection, police and medical
services would decrease.
3-160
-------
3.7.2.2 The Action Alternatives Including the Proposed Action
Impacts on the human resources in the area of the proposed mine site have not
been evaluated in the same subsystem format as the other resources previously
presented. The human resources evaluation presents the no action alternative
versus Mobil's proposed action except in the discussion of land use where
alternative reclamation plans are discussed and product transport where alter-
native modes of transportation are discussed.
3.7.2.2.1 Demographics and Economics
During the two construction periods at the South Fort Meade site, construction
labor would average 400 employees with a peak labor force of 600 employees.
Approximately 95 percent of the construction labor would come from the exist-
ing central Florida labor pool, providing ongoing employment for construction
industry personnel in the area. Permanent operating employment is expected to
stabilize at 233 employees, most of whom would be transferred from the exist-
ing Fort Meade Mine while the rest would be hired from the local labor pool.
Total regional secondary employment generated by operation of the facility is
projected to be between 900 and 1,430. Total secondary income from indirect
employment is estimated at $350 million.
Construction labor expenditures for the two phases of development would total
$240 million (1980 dollars), with the total labor payroll at $70 million. The
annual operations payroll for the mine would be approximately $5.1 million
(1980 dollars) per year. Most of the construction labor expenditures, and
essentially all of the operations expenditures, would accrue to the region.
Mobil's proposed South Fort Meade Mine would generate revenue for Polk County
through ad valorem taxation and redistribution of sales tax collected in Polk
County. Once operations commence, the annual revenue generated (in 1980
dollars) by the proposed mine is estimated at $2.2 million in property tax and
$300,000 in sales tax. Approximately 35 percent of the ad valorem revenue
would go to the general county fund, 62 percent to the school district, and 3
percent to the SWFWMD and the Peace River Basin Water District. The mining
operation would also generate about $5.6 million in severance tax revenue
annually, of which 50 to 75 percent would go to the General Revenue Fund of
3-161
-------
the State of Florida. The remainder of the revenue would be credited to the
Land Reclamation Trust Fund and the Florida Institute of Phosphate Research.
3.7.2.2.2 Cultural Resources
Pursuant to Section 106 of the National Preservation Act, EPA consulted with
the State Historic Preservation Officer (SHPO) and the Florida Division of
Archives, History and Records Management, to obtain an evaluation of the cul-
tural resource impacts on the Mobil project. Based on the inventory conducted
by Florida State Museum authorities, archival and field evidence indicates the
absence of prehistoric or historic resources of National Register quality
within the proposed mine site's boundaries. The site is not close to any
known historic or archaeologic site. The SHPO provided EPA his opinion that
the proposed South Fort Meade mine is unlikely to affect any archaeological or
historic sites listed, or eligible for listing, on the National Register of
Historic Places, or otherwise of national, state or local significance (Percy,
1980).
3.7.2.2.3 Community Services
The proposed South Fort Meade facility will essentially be a replacement mine
for a currently active Mobil mine in Polk County. The labor force for the new
facility will generally be drawn from that of the phased-out existing facility
and would not result in an influx of people that would impose additional de-
mands on the present community service facilities. Therefore, the new facil-
ity is considered not to have an impact on community services.
3.7.2.2.4 Land Use
The principal socio-economic issue associated with waste disposal and recla-
mation is the ultimate use of the land after mining. Table 3.7-1 presents a
summary of the land use units that the reclaimed mine site would contain as a
result of each waste disposal/reclamation plan (the proposed action and three
alternatives). Due to the rural setting of the mine site, the ultimate util-
ity of the site for urban purposes is not as important to the economy of the
area as the use of the land for agriculture.
Conventional Clay Settling Plan (Mobil's Proposed Action): During the life of
the mine, 15,194 acres of the 16,288-acre site would be disturbed. The
undisturbed areas of the site are wetlands and flatwoods, considered to be
3-162
-------
TABLE 3.7-1
LAND USE CLASSIFICATION OF RECLAIMED LAND
(Acres)
co
GO
Land Use/
Cover Classification
Agricultural Lands
Cutover Flatwood
Upland Hardwood
Forest
Upland Mixed
Forest
Planted Pine
Water Areas
Forested Stream
Channel
Freshwater Swamp
Freshwater Marsh
Developed
TOTAL
Existing
Use
8,282
3,452
1,804
126
339
13
_
1,014
1,040
218
16,288
Conventional
Plan
11,521
182
664
1,276
453
3
277
589
1,323
0
16,288
Sand/Clay
Cap Plan
11,111
182
664
1,456
536
3
279
615
1,442
0
16,288
Sand/Clay
Mix Plan
10,421
182
664
1,831
431
3
263
857
1,636
0
16,288
Overburden/Clay
Mix Plan
10,421
182
664
1,831
431
3
263
857
1,636
0
16,288
SOURCE: STUDY DATA
-------
economically unproductive in their current use. All of the land area on the
site that is currently economically productive (cropland, improved pasture,
citrus groves and planted pines), about 54 percent of the total site, would be
disturbed as a result of mine implementation.
With the completion of the conventional reclamation plan, agricultural land
would increase 39 percent, from 8,282 acres to 11,521 acres. Most of the
flatwoods (3,452 acres) on the site are presently unmanaged pasture areas and
with the conversion of these areas to managed agricultural units, the economic
productivity of the whole mine site would increase over current levels. The
566 acres of citrus groves on the site (0.3 percent of the citrus producing
land in Polk County) would be lost. Planted pine areas would increase from
339 acres to 453 acres upon completion of reclamation, while other forested
areas would remain essentially unchanged. Freshwater swamps and marsh areas
would also remain with approximately the same acreage.
Sand/Clay Cap Plan: The sand/clay cap reclamation plan would designate 11,111
acres as agricultural land, representing a 34 percent increase over that exist-
ing. Because the 7,580 acres of 4:1 sand/clay cap material would be more till-
able than the 6,681 acres of clay in the conventional plan, the sand/clay cap
plan has a better potential for economic productivity through agricultural use
than the reclaimed land in the conventional plan. Planted pine acreage would
increase from the existing 339 acres to 536 acres with the other forested
areas increasing only slightly in size. Freshwater swamps and marsh areas
would remain essentially unchanged.
Sand/Clay Mix Plan: This reclamation plan would result in 10,421 acres de-
voted to agricultural use, representing a 26 percent increase over the exist-
ing amount. The 3,512 acres of 2:1 sand/clay mix material would be tillable
which would allow for greater agricultural productivity than with the conven-
tional reclamation plan. Planted pine acreage would increase to 431 acres
with the sand/clay mix plan. More acreage (2,120 acres) would be planted as
forest than with the conventional plan (1,930 acres). Freshwater swamp and
marsh acreage would remain essentially as it is.
Overburden/Clay Mix Plan: In this plan, 10,421 acres would be designated for
agricultural use. The 7,670 acres of 2:1 sand/clay mix would be tillable and
3-164
-------
more productive than the 6,168 acres of clay associated with the conventional
plan. Other land use acreages would be similar to those for the sand/clay mix
plan.
3.7.2.2.5 Transportation
Highway and road traffic would be increased as a result of construction and
operation of the South Fort Meade Mine. It is anticipated that most mine-
related traffic would use Mt. Pisgah Road from Fort Meade to County Line Road
to Manley Road to the plant site. County Line Road has an average daily
traffic count (ADT) of 750. The traffic load on County Line Road is con-
sidered typical of traffic on paved routes in the project area and is, there-
fore, used as the basis for comparing premine traffic to the traffic during
mining construction and operation. The following two assumptions have been
made in estimating traffic volumes related to mine construction and operation:
(1) 15 percent of the existing ADT occurs between 10:00 PM and 7:00 AM, the
remainder being distributed evenly throughout the daytime hours; and (2) a car-
pooling factor of 1.7 persons per vehicle is applied to the labor force.
Using these assumptions, the following peak traffic volumes and ADT's are
estimated for Mt. Pisgah Road and County Line Road during Phase I and II
construction and operation periods.
Peak Traffic Volume
Period (vehicles per hour) APT
Existing
(based on 1975) 38 750
Phase I Construction
(maximum period, 1983) 391 1.456
Phase I Operation
(1984) 74 923
Phase II Construction
(1985) 427 1,629
Phase II Operation 94 1.025
(1986-2006)
The flow of mine-related traffic would be opposite to the travel of those
residents who live near the mine and work in adjacent communities.
3-165
-------
The peak traffic volume of 427 vehicles per hour would occur in 1985 when
Phase I operation and Phase II construction activities overlap. The maximum
service volumes for a two lane paved road similar to Mt. Pisgah Road and
County Line Road is estimated as 900 vehicles per hour. Therefore, the peak
project induced traffic on the local roads is still less than half the maximum
service volume. The peak traffic volume would occur during 1985 and would
drop off for the remainder of the mine life. Construction related equipment
would also be transported on the local roadway system from 1982 through 1986,
possibly creating some local short-term traffic congestion problems.
Transportation of the product is the second major transportation demand that
could present a socioeconomic impact. The proposed action (railroad) and
alternative method (truck transport) are discussed below.
Railroad (Proposed Action): The proposed construction of a rail spur from the
existing Seaboard Coast Line tract west of the mine to the beneficiation plant
would be along a 100-foot wide approximately six-mile long corridor acquired
by Mobil. There would be one grade crossing on Mt. Pisgah Road which would be
crossed four times each day. During Phase I operations, the trains would
consist of one locomotive and 33 cars. During Phase II operations, the same
number of train trips would be required but each train would have 65 cars.
Each train crossing would block traffic on Mt. Pisgah Road for approximately
six minutes. The right-of-way for the spur would traverse woodland areas and
improved pasture.
Truck: During Phase I operations, 45 trucks would have to make 260 round
trips per day in order to move the product from the mine to Nichols. Twice as
many round trips would be required to implement Phase II operations. During
Phase I operations, more than 100 additional personnel would be required to
drive the trucks and service them. During Phase II operations, the personnel
requirement would double. The movement of these trucks would increase the
maintenance requirements for area roadways due to the increased vehicle weight
and traffic volumes.
3-166
-------
3.8 REFERENCES
Bromwell, L.G. 1976. Dewatering and Stabilization of Waste Clays, Slimes and
Sludges. Florida Phosphatic Clays Research Project.
Central Florida Regional Planning Council. 1978. Central Florida Areawide
Water Quality Management Plan, Bartow, Florida.
Cowardin, L.M., V. Carter, F.C. Golef, and E.T. LaRue. 1977. Classification
of Wetlands and Deepwater habitats of the United States. Operational
Draft. U.S. Fish and Wildlife Service.
Environmental Science and Engineering, Inc. 1977. Evaluation of Emissions
and Control Techniques for Reducing Fluoride Emissions from Gypsum Ponds
in the Phosphoric Acid Industry, U.S. EPA Contract.
Farmland Industries, Inc. 1981. Development of Regional Impact Application
for Development Approval, Phosphate Mining and Chemical Fertilizer
Complex, Hardee County, FL.
Florida Department of health and Rehabilitative Services. 1978.
Florida Department of Health and Rehabilitative Services. 1975. Radiological
Health Consequences of Mining Operations in Manatee County by Beker
Phosphate Corporation.
Florida Department of Health and Rehabilitative Services. 1981. "Interim
Radiation Exposure and Concentration Limits for Land Use Determination -
Naturally Occurring Radioactivity." Technical Guide 1.
Guidmond, R.J. and S.T. Windheme. 1975. Radioactivity Distribution in
Phosphate Products, By-Products, Effluents, and Wastes. U.S. EPA
Criteria and Standards Div. Tech. Note ORP/CSD-75-3:l-32.
Holzworth, G.C. 1979. Mixing Heights, Wind Speeds, and Potential for Air
Pollution Throughout the Contiguous United States, prepared for the U.S.
EPA, Research Triangle Park, North Carolina.
Kolb, W.O., H. Pardin, A. Spielberg, G. Manning, and K. Maw. 1976. The
Florida Land Use and Cover Classification System. A Technical Report.
Fl. Dept. Admin., Div. St. Plan., Bur. Compreh. Plan.
National Council on Radiation Protection and Measurements. 1975. Natural
Background in the United States, Report No. 45.
PEDCO Environmental Specialists, Inc. 1975. Particulate and Sulfur Dioxide
Area Source Emission Inventory for Duval, Hillsborough, Pinellas, and
Polk Counties, Florida. Vol. I. USEPA Region IV.
PEDCO Environmental Specialists, Inc. 1976a. Air Quality Modeling in
Hillsborough, Pinellas, and Polk Counties, Florida. Vol. I. USEPA
Region IV.
3-167
-------
PEDCO Environmental Specialists, Inc. 1976b. Air Quality Modeling in
Hillsborough, Pinellas, and Polk Counties, Florida. Vol. II. USEPA
Region IV.
Percy, 6. W., 1980. Letter from George Percy, Deputy State Historic Preser-
vation Officer, to A. Jean Tolman, US EPA Region IV, December 16, 1980.
Prince, Robert J. 1977. "Occupational Radiation Exposure in the Florida
Phosphate Industry," M.S. Thesis, University of Florida.
Roessler, C.E., R. Kautz. W.E. Bolch, and J.A. Wethington, Jr. 1978. The
Effect of Mining and Land Reclamation on the Radiological Character-
istics of the Terrestrial Environment of Florida's Phosphate Regions,
The Natural Radiation Environment III Symposium, Houston, Texas.
Roessler, C.E., Z.A. Smith, W.E. Bolch and R.J. Prince, 1979. Uranium and
Radium-226 in Florida Phosphate Materials Health Phys Vol. 37:269-277.
Reppert, R.T., W. Sigleo, E. Stakhiv, L. Messman, and D. Meyers. 1979.
Wetland Values: Concepts and Methods for Wetland Evaluation. IWR
Research Report 79-R1. U.S. Army Engr. Inst. for Water. Res. Kingman
Bid., Ft. Belvoir, Va.
Tessitore, J.L. 1975. Fluoride Data for Polk County, Florida. DER.
Tessitore, J.L. 1976. An Estimate of Total Fluorides Emitted in the Polk-
Hillsborough County Area. DER.
Texas Instruments Incorporated. 1978. Central Florida Phosphate Industry
Areawide Impact Assessment Program. Volume VI, Land.
Todd, D.K. 1959. Ground Water Hydrology. John Wiley and Sons., Inc., New
York, New York.
U.S. Army Corps of Engineers. 1978. Preliminary Guide to Wetlands of Penin-
sular Florida. Major Associations and Communities Identified. Technical
Report Y-28-2. Environmental Effects lab, Vicksburg, MS.
U.S. Environmental Protection Agency. 1978a. Central Florida Phosphate
Industry Areawide Impact Assessment Program, Volume IV: Atmosphere.
U.S. Environmental Protection Agency. 1978. Final Environmental Impact
Statement, Central Florida Phosphate Industry, Volume I Impact of
Proposed Action. EPA 904/9-78-026a.
U.S. Environmental Protection Agency. 1979a. Noise Resource Document, Estech
General Chemicals Corporation Draft Environmental Impact Statement. EPA
904/9-79-044D.
U.S. Environmental Protection Agency, Office of Air and Waste Management,
1977. Compilation of Air Pollutant Emission Factors, AF-2, Pt. A and B,
2nd Edition.
3-168
-------
U.S. Environmental Protection Agency, 1977b. Recommendations for Radiation
Protection of Persons Residing on Phosphate Land, Letter from Douglas M.
Costle EPA Administrator to the Governor of Florida, May 30, 1979.
Wilson, W.E. 1977. Groundwater Resources of DeSoto and Hardee Counties,
Florida, U.S. Geological Survey Report of Investigation, No. 83.
3-169
-------
4.0 SHORT-TERM USE VERSUS LONG-TERM PRODUCTIVITY
The proposed mining and processing of phosphate matrix from the South Fort
Meade Mine involves the progressive use of 15,200 acres of the site during an
expected 25-year mine life. Approximately seven percent of the 16,300-acre
site would be left in its present state. The site's productivity currently
includes range and pasture, wildlife and water. The following discussion of
short-term use versus long-term productivity is arranged by environmental
discipline groups.
4.1. METEOROLOGY. AIR QUALITY AND NOISE
4.1.1. SHORT-TERM
As a result of the plant construction, mining, beneficiation and transshipment
of phosphate rock, emissions of gases and particulates would be increased.
Emission sources would include the beneficiation plant (e.g., flotation rea-
gents), internal combustion engines (e.g., earthmovers), land clearing opera-
tions (e.g., wind-blown dust) and dust particles from increased vehicle
traffic, mining and processing operations. Noise levels would increase in the
immediate vicinity of active land clearing, mining and reclamation operations,
near the beneficiation plant, and near the railroad spur and roadway systems
into the plant. At times, these emissions and noise levels may disturb nearby
wildlife and disrupt existing wildlife usage patterns.
4.1.2 LONG-TERM
Since mining and processing will continue for 25 years and reclamation acti-
vities an additional 10 years thereafter, the short-term effects generated by
these activities may also be viewed as long term. At the conclusion of the
mining and reclamation operations, project generated emissions and noise would
cease.
4-1
-------
4.2 GEOLOGY AND SOILS
4.2.1 SHORT-TERM
Soils and surface geology will be totally disrupted over the 15,194 acres.
Agricultural productivity in the short term will be increasingly diminished
over the life of the mine until reclamation activities "catch up" and overtake
acreages under mining. The disturbed lands utilized as waste disposal areas
would not have structural properties compatible with the construction of
buildings.
4.2.2 LONG-TERM
The reclaimed clay settling areas would have certain improved agronomic prop-
erties compared to the existing soils characteristic to the site. The high
nutrient availability and enhanced moisture and nutrient retention capacity of
the reclaimed clay soils would improve the agricultural productivity of the
site. The poor structural stability of the reclaimed clay settling areas
would preclude building over the long term.
4.3 RADIATION
4.3.1 SHORT-TERM
Increased levels of radioactivity would result during mining. These short-
term exposure levels would not present significant problems to the workers or
the environment.
4.3.2 LONG-TERM
Radon gas emissions from the reclaimed waste settling areas would continue at
low concentrations for a significant time into the future. Restrictions would
be required on structures built on reclaimed clay settling areas to prevent
the build up of radon gas.
4.4 GROUNDWATER
4.4.1 SHORT-TERM
Groundwater withdrawal for matrix processing would create a cone of depression
in the Lower Floridan Aquifer. The calculated drawdown in the piezometric
4-2
-------
surface at the property boundaries would range from a maximum of 4.3 feet to
less than one foot. Withdrawals and pit seepage of water from the Surficial
Aquifer would slightly reduce the baseflow contributions to adjacent streams.
4.4.2 LONG-TERM
The placement of clay basins over 9,683 acres of the site would reduce ground-
water recharge to the Surficial Aquifer. The weighted average recharge for
the total site would be reduced by approximately 46 percent.
4.5 SURFACE WATEj
4.5.1 SHORT-TERM
Mining and waste disposal operations at the South Fort Meade site would result
in the disturbance of tributaries to Bowlegs Creek and the Peace River. Flood-
plains and low flow values of the Peace River downstream of the site would be
slightly altered (less than four percent). Organic loads from on-site tribu-
taries to Bowlegs Creek and the Peace River would be decreased by less than
two percent.
Discharges of excess water from the recirculatiop water system would con-
tribute mass loadings of TSS, total phosphorus, fluorides and other minor
constituents to the Peace River. Water quality is not expected to change
significantly as a result of these discharges.
4.5.2 LONG-TERM
Some minor alterations of surface runoff quantities and peak flows would be
observed after reclamation. The clay content of the reclaimed soils in clay
settling areas would cause increases in the total runoff quantities and peak
flows expected after precipitation. Additional areas with agricultural vege-
tation would also increase peak runoff flows. The marsh areas and shallow
pools would provide water storage.
After reclamation, water quality of the streams would be primarily influenced
by pollutants carried in the runoff. The site would be reclaimed to agricul-
tural and silvicultural uses, similar to present land use. Small marsh areas
established in the above-grade reclaimed areas and two large wetland areas
4-3
-------
(totaling 1,513 acres) would accumulate surface runoff from surrounding upland
areas, trap much of the sediment, and filter much of the excess nutrients. As
the reclaimed streams mature, the channels would form natural meanders. The
water quality found within the mature reclaimed streams should be similar to
that presently found in the streams.
4.6 BIOLOGY
4.6.1 SHORT-TERM
Development of the South Fort Meade Mine would result in the destruction of
15,194 acres of terrestrial and aquatic habitat. Some aquatic and terrestrial
species would be lost if they do not migrate to unaffected areas as mining
gradually progresses. Some individuals of sensitive species, such as the in-
digo snake and alligator, would be lost but the regional populations should
not be affected (see Section 7.3, Coordination). Preserved areas such as Bow-
legs Creek, the Peace River, and the cypress dome would aid in re-establishing
populations after mining and reclamation activities are complete.
4.6.2 LONG-TERM
Approximately 75 percent of the existing site is currently used for cattle
grazing, including pasture, flatwoods, and bayheads. Reclamation plans pro-
pose the use of a majority (71 percent) of the site as improved pasture, which
represents a 67 percent increase in improved pasture on the reclaimed site.
Such areas would not provide all of the habitat requirements for the species
which now inhabit the site; thus, a long-term loss in the wildlife produc-
tivity of these areas would occur. Additional changes in habitat, such as
replacing upland hardwood forest with upland mixed forest and freshwater swamp
with freshwater marsh and forested stream channels, would occur. The re-
claimed vegetative cover would take an extended time (over 30 years) to allow
invasion of other plant species which would eventually restore the diversity
of the habitat to the site.
4-4
-------
4.7 HUMAN RESOURCES
4.7.1 SHORT-TERM
The South Fort Meade Mine project would provide continued jobs for the 175
personnel now employed at Mobil's Fort Meade Mine plus an additional 58 new
jobs, increasing employment in Polk County and the central Florida area.
Construction and new operation labor requirements for the project would pri-
marily come from the local area. Tax revenues generated by the mine would
more than pay for community service requirements of the Mobil employees.
Mining would destroy any historical site which might be present on the South
Fort Meade site. However, no significant archaeological sites have been
identified on the property (see Section 7.4, Consultation with the State
Historic Preservation Officer).
4.7.2 LONG-TERM
Development of the proposed mine would sustain Mobil's economic contribution
to the long-term economic growth within Polk County. The proposed South Fort
Meade Mine would replace the existing Fort Meade Mine as a source of employ-
ment and tax revenue generation, upon which Polk County is dependent. The in-
creased agricultural land and improved productivity should allow for growth of
the agricultural sector of the area's economy.
4-5
-------
5.0 IRREVERSIBLE OR IRRETRIEVABLE
COMMITMENTS OF RESOURCES
This section presents a discussion of those resources which would be consumed,
depleted, permanently removed, destroyed or irreversibly altered by the pro-
posed mining operation on the Mobil site.
5.1 DEPLETION OF MINERAL RESOURCES
The extent of recoverable U.S. phosphate reserve has been estimated at 2.2
billion metric tons (U.S. General Accounting Office, 1979). World reserves of
phosphate rock are estimated by the U.S. Bureau of Mines to be about 27 bil-
lion metric tons, but may be much larger (e.g., in 1971 the British Sulphur
Corp. estimated world reserves of all grades to be 130 billion metric tons).
The estimated current world phosphate rock production is about 120 million
metric tons. The U.S., USSR, and Morocco are by far the largest producers of
rock, accounting for 41, 26, and 15 percent of world production, respectively.
Morocco, however, is the leader in identified reserves with 66.7 percent of
the world's supply, with the U.S. and USSR accounting for only 8.1 and 3.3
percent of the identified reserves, respectively.
The Bone Valley formation of central Florida is the source of most of the U.S.
production, accounting for about 75 percent of total production (which ap-
proached 50 million metric tons in 1978).
Two projections of U.S. phosphate rock production have been made-one by the
U.S. Bureau of Mines and one by Chase Econometric Associates (U.S. General
Accounting Office, 1979). The Chase forecast indicates that domestic produc-
tion will increase to 112 million short tons by 2025, but fails to identify
the source of these reserves. The U.S. Bureau of Mines, on the other hand,
predicts that U.S. production will peak in 1985, and then decline. Because
the U S Bureau of Mines has not identified any future potential reserves,
their*forecast predicts that high grade reserves will be virtually exhausted
by 2010.
5-1
-------
The U.S. General Accounting Office (1979) has recommended:
"...that the Secretary of the Interior make a thorough review of
the Nation's long-range phosphate position, and report to the Congress on
its future availability, and if appropriate, to suggest legislative
actions needed to ensure supply. Such a review should be submitted to
the Congress by December 1981 and include the following:
1. A comprehensive assessment of the phosphate reserves of the nation
and the world. To the extent that this is based on unverified data,
the Secretary should judge the reliability of such data and the need,
if any, for Government verification of proprietary (source) records.
2. A determination of the extent to which noneconomic trade-offs, such
as environmental needs and other land-use needs, are likely to limit
future phosphate development.
3. A review and evaluation of alternatives to import dependency and as-
sessment of their costs.
4. A submission from the Department of Agriculture contributing to the
comprehensive phosphate assessment by estimating future needs and
possible food production alternatives to being dependent on foreign
fertilizer sources."
In March of 1980, then Secretary of the Interior Cecil D. Andrus responded to
the above recomnendations. In his letter (Andrus, 1980) he stated that the
Department of Interior's most recent projections were consistent with the
statements in the U.S. General Accounting Office Report, stating "that the
United States will continue to be a net exporter of phosphate until at least
the year 2000". Since there is no projected shortage of domestic phosphate,
Andrus requested an extension (to December 1982) for the completion of the
report to the Congress.
From the U.S. Bureau of Mines projections, total cumulative U.S. phosphate
production over the next 20 years should be on the order of 1.2 billion tons.
Over the 25-year life of Mobil's proposed mining operation, a total of approxi
mately 77 million tons of phosphate rock would be removed. From 1984 to 1986
5-2
-------
the production rate would be 1.7 million tons per year. When Phase II begins
in 1987, the production would increase to 3.4 million tons per year, or about
5.6 percent of the annual U.S. production. While this represents an irrever-
sible and irretrievable loss of reserves, data are not available to evaluate
this loss with respect to future domestic needs and availability.
5.2 LANDFORM CHANGES
The mining/processing of phosphate on the Mobil site would result in an ir-
reversibly altered landform. Natural soil profiles will be destroyed and ex-
isting vegetation cleared. In addition, storage of waste clays will result in
the creation of 8,170 acres of diked disposal areas with an average height of
39 feet. The land use of the reclaimed site will primarily be for improved
pasture and mixed forests, rather than the pine flatwoods and hardwood forests
which now predominate.
5.3 CHEMICALS AND REAGENTS
The total expected quantities of reagents to be consumed at the proposed South
Fort Meade Mine are listed below. Chemical reagents used in the flotation
process would not be recoverable.
Total Usage Over
Usage Rate Mine Life
Reagent (gal/ton of phosphate) (millons of gallons)
No. 5 Fuel oil 0.45 34.1
Kerosene 0.05 3.6
Caustic 0.02 1.5
Fatty Acid 0.29 21.6
Amine 0.06 4.3
Sulfuric Acid 0.03 24.5
5-3
-------
5.4 WATER
A maximum of 16.4 mgd of water may be pumped from the groundwater under the
authorization of the SWFWMD CUP. Mobil plans to obtain 0.7 mgd from the
Upper Floridan Aquifer and the balance (15.7 mgd) from the Lower Floridan Aqui-
fer. The total volume of water withdrawn from the Floridan Aquifer over the
26-year life of the mine plus the initial (18-month) reservoir filling period
would be 165 billion gallons. The disposition of this water is expected to be
as follows:
Total over the
Mine Life
(gal x 109)
Water contained in
phosphate rock leaving
the site 0.33 2.9
Seepage from ponds
on the site 2.7 21.8
Water in waste clay and sand
tailings on the site 13.3 107.0
5.5 ENERGY
Energy usage for all purposes is expected to be 247,000 MWh per year in Phase
I and 372,300 MWh during Phase II. The total energy use over the life of the
project will be about 8,200,000 MWh or about 110 kWh per ton of phosphate rock
produced.
5.6 FISH AND WILDLIFE HABITAT
Existing fish and wildlife habitats on 15,194 acres of the 16,288 acres com-
prising the proposed South Fort Meade Mine would be disturbed during the oper-
ation of the mine. The disturbed habitats would be removed during mining and
replaced during reclamation. Some interim mine ponds and spoil areas would
naturally revegetate and provide interim habitat. The changes in wildlife
habitat acreage are identified in the following chart.
5-4
-------
and replaced during reclamation. Some interim mine ponds and spoil areas
would naturally revegetate and provide interim habitat. The changes in wild-
life habitat acreage are identified in the following chart.
Agricultural
Cutover Flatwoods and
Bayhead
Upland Hardwood Forest
Upland Mixed Forest
Planted Pine
Water Areas
Forested Stream Channel
Freshwater Swamp
Freshwater Marsh
Developed
TOTAL
Existing
(acres)
8,282
Undisturbed
(acresj_
108
Reclaimed
(acres)
11,413
Post
Mining Change
(acres) (feres)
16,288
1,094
15,194
16,288
11,521 +3239
3,452
1,804
126
339
13
0
1,014
1,040
218
182
664
5
0
3
0
111
21
0
0
0
1,271
453
0
277
478
1,302
0
182
664
1,276
453
3
277
589
1,323
0
-3270
-1140
+1150
+ 114
9
+ 277
- 426
+ 283
- 218
As indicated in the chart, 3,239 additional acres would be committed to agricul
tural use after reclamation is completed. This is roughly equivalent to the
3,270-acre loss of cutover flatwoods and bayhead habitat. Approximately 80 to
90 percent of the cutover flatwoods would also be used for grazing by cattle
and would have marginal value as wildlife habitat. The 1,140-acre loss of
upland hardwood forest would be offset with 1,150 acres of upland mixed forest
planted with nursery stock. The existing 339 acres of planted pine would be
harvested for pulpwood and reclamation would replace them with 453 acres of
planted pine. Wetland habitat would be reproportioned, with an additional 277
acres of forested stream channel and 283 acres of additional freshwater marsh.
Freshwater swamp habitat would be reduced by 426 acres after mining and
reclamation are complete.
5-5
-------
Some individuals of threatened species, such as the indigo snake and the
American alligator, would be lost (estimated loss in the range of 10 each).
5.7 HISTORICAL AND ARCHAEOLOGICAL RESOURCES
As discussed in Section 3.7 (Human Resources) there is no evidence of the
presence of significant archaeological artifacts or major historical sites on
the proposed mine site. Excavation of overburden and ore from the site could
destroy previously unfound artifacts unless their presence is noticed during
the mining process and excavation is undertaken.
5.8 REFERENCES
Andrus, C.D. 1980. Letter from Secretary of Interior Cecil D. Andrus to
Represent!ve Jack Brooks, Chairman of the Committee on Government
Operations, March 27, 1980.
U.S. General Accounting Office. 1979. Phosphates: A Case Study of a
Valuable, Depleting Mineral in America. Report by the Comptroller
General to the Congress, EMD-80-21.
5-6
-------
6.0 COMPARISON OF PROPOSED ACTIVITY WITH
AREAWIOE EIS RECOMMENDATIONS
The Final Areawide Environmental Impact Statement for the Central Florida
Phosphate Industry published by EPA in November, 1978, evaluated the impact of
various alternatives for phosphate mining in central Florida. The EPA recom-
mendations represent a scenario of phosphate development determined to be as
compatible as practicable with other desired and intended land uses. These
recommendations provide a decision-making tool for consideration for all new
phosphate mines in central Florida. The following discussion compares Mobil's
proposed action with the Areawide EIS recommendations for mining and benefi-
ciation. In addition, where EPA's proposed action and recommended alterna-
tives differ from Mobil's proposed action (as in the case of waste disposal),
EPA's proposal is also compared to the Areawide EIS recommendations.
6.1 MINING AND BENEFICIATION REQUIREMENTS
6.1.1 ELIMINATE THE ROCK-DRYING PROCESSING AT BENEFICIATION PLANTS AND
TRANSPORT WET ROCK TO CHEMICAL PLANTS
Mobil's proposed project does not include a rock dryer and calls for all wet
rock to be transported from the site in a wet condition.
6.1.2 MEET STATE OF FLORIDA AND LOCAL EFFLUENT LIMITATIONS FOR ANY
DISCHARGES
Pursuant to Section 401 of the Federal Water Pollution Control Act as amended
(33 USC 1251), the State of Florida issues certification to each applicant for
a National Pollutant Discharge Elimination System (NPDES) permit. All recent
NPDES permits issued by the state for phosphate mining facilities have been
certified subject to the following conditions:
6-1
-------
o The applicant must comply with all applicable requirements of Chapter
403, Florida Statutes, and Chapter 17 series, Florida Administrative Code
(FAC).
o Issuance of certification does not constitute state certification of any
future land alteration activities which require other Federal permits
pursuant to Section 404 of P.L. 92-500, as amended, nor does it consti-
tute approval or disapproval of any future land alteration activities
conducted in waters of the state which require separate department per-
mit(s) pursuant to Section 17-4.28, FAC.
o In accordance with Section 17-6.01(2)(a)2a.D., FAC, the following ef-
fluent limitations apply to all discharges designated as possibly con-
taining contaminated runoff, process generated wastewater, or mine
dewatering discharges from the mining and beneficiation of phosphate
rock.
Discharge Monitoring
Characteristics Limitations Requirements
1-Day Max. 30-Day Avg. (Once per week)
Total Suspended
Solids (mg/1) 25 12 l/wk/24-hour composite
Total Phosphorus (mg/1} 5 3 l/wk/24-hour composite
pH 6.0-9.0 6.0-9.0 grab sample
If the above requirements are met, the discharge from this facility will com-
ply with Sections 301, 302 and 303 of the Federal Water Pollution Control Act,
as amended.
This certification must indicate that the terms and conditions of the NPDES
permit will result in compliance with Sections 301, 302 and 303 of the Federal
Water Pollution Control Act, as amended. The state may impose, as additional
requirements, applicable state law or regulations related to water quality
standards.
6.1.3 ELIMINATE CONVENTIONAL ABOVE-GROUND SLIME-DISPOSAL AREAS
The elimination of conventional above-ground clay disposal areas is recom-
mended by the Areawide EIS. In order to meet this recommendation, the Area-
wide EIS encouraged the use of waste clays, or a mixture of sand tailings and
waste clays, in reclamation. At the same time, the need for an initial above-
ground storage area and for retaining dikes around sand/clay mix areas was
recognized. The Areawide EIS also noted that if the percentage of waste clay
at a mine exceeds the proportionate amount that can be utilized, the incre-
mental amounts beyond that which can be handled by new clay dewatering methods
6-2
-------
may be placed in a holding pond for reclamation after adequate settling (i.e.,
conventional settling).
The proportionate amount of clay at the Mobil mine site is high relative to
other mines in the region (Table Ł.5-1). The proportion of clay, commonly
expressed as a sand to clay ratio, is only 1.2:1 at the Mobil site. This sand
to clay ratio at the site is insufficient to allow for complete sand/clay mix
waste disposal. Therefore, Mobil proposes to use a modification of the con-
ventional above-ground waste disposal method. The modification consists of
stage-filling the clay disposal areas (9,683 acres) to obtain increased
settling, followed by capping 15 percent (1,489 acres) of the clay settling
areas with sand tailings. Following reclamation, 6,681 acres of above-grade,
uncapped clay settling areas would remain as the predominant landform. The
average dike height for this waste disposal plan is 38.7 feet above natural
grade. From 385 acres to a maximum 2,790 acres of clay settling areas would
be active at a given time during the life of the mine. EPA's preferred
action, however, is the use of the sand/clay cap waste disposal alternative.
Sand/clay cap clay settling areas are not considered "conventional". After
the settling basins are initially filled with clay, they are actively
dewatered to form a surface crust and then a second stage fill of sand/clay
mix (4:1) is added to cap the area. The sand/clay cap would average five feet
thick over the area. The sand/clay cap waste disposal plan would have 7,580
acres of above-grade sand/clay cap areas and no above-grade clay settling
areas. The settling areas, active at one time, would range from 590 acres to
1,860 acres during the life of the mine.
6.1.4 MEET SOUTHWEST FLORIDA CONSUMPTIVE USE PERMIT REQUIREMENTS
The Areawide EIS reconmends that any new source mine and beneficiation plant
meet Southwest Florida Water Management District's (SWFWMD) Consumptive Use
Permit (CUP) requirements. Mobil is obligated to the terms and conditions of
their SWFWMD CUP No. 205403 issued on October 7, 1980. Should Mobil fail to
comply with all of the conditions set forth in the permit, the permit will
automatically become void.
6-3
-------
6.1.5 PROVIDE STORAGE THAT ALLOWS RECIRCULATION OF WATER RECOVERED FROM
SLIMES
The Areawide EIS recommends that a new source mine provide storage that allows
recirculation of water recovered from clays. The water recirculation system
for Mobil's proposed mining and beneficiation facility would provide for con-
tainment and for approximately 90 percent water recirculation so that a dis-
charge should occur only occasionally during heavy rainfall periods.
6.1.6 USE CONNECTOR WELLS
The Areawide EIS recommends the use of connector wells. At the South Fort
Meade site the transmissivity of the Surficial Aquifer is rather low (11 to
439 gpd/ft), and the gross alpha radiation levels were found to be high (0.4
to 77 pCi/1). Therefore, Mobil does not propose to use connector wells to re-
charge the Floridan Aquifer with groundwater from the Surficial Aquifer, nor
is the use of connector wells a condition of Mobil's SWFWMD CUP.
6.1.7 ADDRESS PROPOSED REGULATIONS REGARDING RADIATION LEVELS TO BE PUBLISHED
BY EPA AND PROJECTED BY MINING AND RECLAMATION PLANS FOR NEW SOURCE
MINES BASED ON TEST BORINGS OF MATERIAL TO BE ENCOUNTERED, AND DEVELOP
A RECLAMATION PLAN THAT CONSIDERS RADIATION OF SPOIL MATERIAL AND RE-
DUCES AS MUCH AS POSSIBLE THE AMOUNT OF RADIONUCLIDE-BEARING MATERIAL
LEFT WITHIN 3-4 FEET OF THE SURFACE
Mobil proposes to practice leach zone management by pocket toe spoiling tech-
niques during mining. This would significantly minimize the impact of redis-
tributing naturally occuring radionuclides during the mining operation and
would reduce surface radiation levels on reclaimed landforms. Even with leach
zone management, redistribution of radioactive materials (sand and clay from
the matrix) will occur. Surface soil radium-226 levels for reclaimed lands
are expected to range from 1 pCi/g for the 477 acres of overburden fill areas
to 22 pCi/g for the 6,681 acres of above-grade clay settling areas and 1,513
acres of below-grade clay settling areas. Estimated radium-226 concentrations
for the 5,034 acres of sand tailings capped with overburden and 1,489 acres of
above-grade clay capped with sand tailings are 3 pCi/g. With the EPA
6-4
-------
preferred alternative (sand/clay cap waste disposal and reclamation plan),
soil radium-226 concentrations are expected to range from 1 pCi/g for the 432
acres of overburden fill to 22 pCi/g for the 1,513 acres of below-grade clay
settling areas. A total of 5,079 acres of sand tailings capped with over-
burden would have an estimated soil radium-226 concentration of 3 pCi/g. The
major difference between this alternative and the conventional plan is that
the large area of clay capped with a sand/clay mix (7,580 acres) would have an
estimated soil radium-226 concentration of 10 pCi/g, whereas the conventional
plan had 6,681 acres of above-grade clay settling areas at 22 pCi/g.
Should buildings (such as residences) be located on the reclaimed site, indoor
radon and radon progeny concentrations would be higher in these structures
than outdoors. For any homes that are constructed on reclaimed land with
Mobil's proposed conventional waste disposal and reclamation plan, the pre-
dicted indoor radon progeny could range from 0.0082 WL over reclaimed sand
tailings areas capped with overburden (5,034 acres) to 0.0172 WL over
reclaimed clay settling areas (6,681 acres). The value for homes over clay
settling areas capped with sand tailings (1,489 acres) would be 0.0121 WL.
With the EPA preferred alternative, the sand/clay cap waste disposal/recla-
mation plan, the predicted indoor radon progeny would be 0.0082 WL over
reclaimed sand tailings capped with overburden (5,079 acres), 0.0158 WL over
reclaimed clay settling areas capped with overburden (590 acres), and 0.0126
WL over reclaimed clay setting areas capped with sand/clay mix (7,580 acres).
The net effect of the sand/clay cap plan versus the conventional plan on
indoor radon progeny concentrations would be a reduction from 0.0172 WL to
0.0126 WL on approximately 6,000 acres of land.
Specific guidance was provided by EPA (1979) for new homes on any reclaimed
land, debris-covered areas, and unmined lands containing phosphate resources:
"IV. Development sites for new residences should be selected
and prepared, and the residences so designed and sited, that the
annual average indoor ...'Working Levels'... do not exceed...
background levels."
If the final guidance for reclaimed lands is similar to the recommendation
quoted above, then the upper limit of predicted WL's in slab-on-grade homes
6-5
-------
will be approximately 0.009 WL (normal background of 0.004 WL plus the uncer-
tainty of 0.005 WL). Under either reclamation plan (Mobil's proposal or EPA's
preferred plan) a large portion of the reclaimed Mobil site would exceed this
upper range. Residential development of the reclaimed site is not planned or
anticipated. If residences were planned they could not be slab-on-grade; they
would have to be designed to prevent the accumulation of radon progeny concen-
trations above the 0.009 WL limit.
6.1.8 MEET COUNTY AND STATE RECLAMATION REQUIREMENTS AND INCLUDE AN INVENTORY
OF TYPES OF WILDLIFE HABITAT IN THE AREA TO BE MINED AND THE AREA IM-
MEDIATELY SURROUNDING IT
Mobil's proposed South Fort Meade Mine is defined in Section 380.06, Florida
Statutes, as a Development of Regional Impact (DRI). In accordance with state
regulations for DRI's, on May 11, 1981, Mobil submitted an application for
Development Approval to Polk County and the State of Florida. Mobil's
proposed project as contained in the DRI document and Application meets all
the State of Florida Department of Natural Resources requirements for recla-
mation (Chapter 16C-16, Florida Administrative Code). Therefore, if and when
Mobil receives an approved Development Order from Polk County, its mining and
reclamation plan will meet all reclamation requirements of the State of
Florida as well as the county.
An inventory of the types of wildlife habitat in the area to be mined by Mobil
and in the immediate surrounding area was made and is included in the EIS.
6.1.9 THE MINING AND RECLAMATION PLAN WILL TAKE INTO ACCOUNT THE PROTECTION
AND RESTORATION OF HABITAT SO SELECTED SPECIES OF WILDLIFE WILL BE
ADEQUATELY PROTECTED DURING MINING AND RECLAMATION
Mobil's mining plan calls for 50-acre parcels to be cleared ahead of each
dragline. Approximately 15,194 acres would be altered and reclaimed during
the life of the proposed South Fort Meade Mine. Mobil's proposed reclamation
plan would restore the 15,194 acres to various land use and cover categories,
including 60,000 linear feet of stream channels. The net effect of Mobil's
proposed action and EPA's preferred alternative on the extent of the general
6-6
-------
vegetation associations which currently exist on the site would be as shown on
Tables 6.1-1 and 6.1-2.
Both Mobil's and EPA's preferred waste disposal/reclamation plans would
greatly increase the acreage on the mine site devoted to improved pasture.
However, the acreage occupied by upland mixed forest, planted pine and fresh-
water marsh would also increase. Transitional wetland species would be
planted in the floodplain of the reclaimed streams. Only native species would
be used in the reclamation plantings.
Among the species that would be adversely affected by the project is the
eastern indigo snake listed as a threatened species by the U.S. Fish and Wild-
life Service (USF&WS). In order to assess the impact which the project will
have on this species' population, consultation procedures were implemented
with the USF&WS (see Section 7.0 Coordination). Consultation also revealed
the presence of an eagle nest adjacent to the Mobil site and potentially sub-
ject to disturbance by the proposed mining activities. The USF&WS provided
EPA with a Biological Opinion regarding the effects of the project on endan-
gered and threatened species, stating that the proposed project is not likely
to jeopardize the continued existence of any listed species or adversely
modify habitat essential for their existence. Mitigating measures recommended
by USF&WS have been incorporated as conditions to the NPDES permit.
6.1.10 PROTECT OR RESTORE WETLANDS UNDER THE JURISDICTION OF THE CORPS OF
ENGINEERS, SECTION 404, FEDERAL WATER POLLUTION CONTROL ACT, PURSUANT
TO 404(b) GUIDELINES (40 CFR 230)
Federal jurisdiction over wetlands is based primarily on Section 404 of the
Clean Water Act of 1977 (33 USC, 1344), formerly known as the Federal Water
Pollution Control Act, in which wetlands are defined, their uses and values
described and a basis for regulation presented. Subsequently, vegetation
lists were developed to assist in defining wetlands (U.S. Army Corps of
Engineers, 1978), and a functional and physical approach to wetland classifi-
cation has been developed (Cowardan et al., 1977). Reppert et al. (1979) pro-
vide a technical concept and procedure for evaluation of wetlands based on the
6-7
-------
00
TABLE 6.1-1
EFFECT OF MOBIL'S PROPOSED RECLAMATION PLAN
Acreage
Vegetation Current
Association Acreage
Improved
Pasture
Cutover
Flatwoods
Upland Hardwood
Forest
Upland Mixed
Planted Pine
Water Areas
Forested Stream
Channel
Freshwater
Swamp
Freshwater
Marsh
Developed
Citrus
7716
3452
1804
126
339
13
1014
1040
218
566
Disturbed
Acreage
7608
3270
1140
121
339
10
-
903
1019
218
566
Preserved
Acreage
108
182
664
5
0
3
0
111
21
0
0
Reclaimed
Acreage
11,413
0
0
1271
453
0
277
478
1302
0
0
Post-Reclamation Current: KOST
Acreaqe Reclamation
11,521
182
664
1276
453
3
277
589
1323
0
0
+3805 (+49%)
-3270 (-95%)
-1140 (-63%)
+1150 (+913%)
+114 (+34%)
-10 (-77%)
+277
-425 (-42%)
+283 (+27%)
-218 (-100%)
-566 (-100%)
16,288
15,194
1094
15,194
16,288
-------
TABLE 6.1-2
EFFECT OF ERA'S PREFERRED ALTERNATIVE RECLAMATION PLAN
Acreage
Vegetation Current
Association Acreage
Improved
Pasture
Cutover
Fl atwoods
Upland Hardwood
Forest
Upland Mixed
Forest
Planted Pine
Water Areas
Forested Stream
Channel
Freshwater
Swamp
Freshwater
Marsh
Developed
Citrus
7716
3452
1804
126
339
13
-
1014
1040
218
566
117288
Disturbed
Acreage
7608
3270
1140
121
339
10
-
903
1019
218
566
157T9T
Preserved
Acreage
108
182
664
5
0
3
0
111
21
0
0
Reclaimed
Acreage
11,003
0
0
1451
536
0
279
504
1421
0
0
15,194
Post-Reclamation Current: Post
Acreage Reclamation
11,111
182
664
1456
536
3
279
615
1442
0
0
16,288
+3395 (+44%)
-3270 (-95%)
-1140 (-63%)
+1330 (+1056%)
+224 (+58%)
-10 (-77%)
+279
-399 (-39%)
+402 (+39%)
-218 (-100%)
-566 (-100%)
-------
requirements of the Clean Water Act. The procedure emphasizes ecosystem func-
tional criteria and structural characteristics rather than the presence of
certain species as criteria. This provides a basin-wide assessment among wide-
ly varying wetland types and allows an evaluation of a particular site as a
unit within a larger system.
In the Final Areawide Environmental Impact Statement for the Central Florida
Phosphate Industry (EPA, 1978), the U.S. Environmental Protection Agency
established a wetlands categorization system to serve as a guideline for regu-
lating the mining and reclamation of wetlands. This system entailed the as-
sigment of wetlands on new source mine sites into one of three categories:
Category 1: Preserve and Protect - Wetlands that must be preserved and pro-
tected without disruption. Wetlands within and contiguous to rivers and
streams having an average annual flow exceeding 5 cubic feet per second as
well as other specific wetlands determined to serve essential environmental
functions, including water quality. (These are wetlands that provide an es-
sential synergistic support to the ecosystem and that would have an unaccep-
table adverse impact if they were altered, modified, or destroyed.) This
generally includes cypress swamps, swamp forests, wet prairies, and certain
freshwater marshes.
Category 2: Mine and Restore Equivalent Acreage - Wetlands that should be
restored as wetlands to perform useful wetland functions. This also includes
certain isolated noncategory wetlands that serve a primary function or several
minor functions that may be maintained through proper restoration.
Category j: Mine With Mo Restoration of Wetlands - Wetlands that would not
have to be restored as wetlands. These are isolated and normally intermittent
in nature, have less significant hydrological functions than Category 2, and
minimal life-support value.
The wetlands identified on the proposed South Fort Meade Mine Site have been
defined and evaluated according to the requirements of Section 404 of the
Clean Water Act and then categorized according to the guidelines presented in
6-10
-------
the Areawide EIS (EPA, 1978). The Reppert et al. (1979) procedure supple-
mented with a Delphi technique for weighting criteria was utilized to conduct
a site-specific determination of wetlands and their functional significance on
the proposed site. Site-specific conditions were used to assist in estab-
lishing the baseline from which the evaluation and categorization were made.
Mobil's proposed action and EPA's preferred alternative would result in the
loss and protection of the following acreages of each of the wetland
categories:
Category 1
Category 2
Category 3
Acres
Existing
84
1,601
370
Acres
Disturbed
0
1,553
370
Acres
Protected
84
48
0
Percent
Protected
100
3
0
Total: 2,055 1,923 132 6
Approximately 1,923 acres designated as wetlands (94 percent of total wetland
acreage) would be eliminated by mining. The preserved wetlands (132 acres)
are primarily the large (75 acre) cypress dome on the eastern edge of the pro-
perty and wetland areas within buffer strips along the Peace River (450 feet
each side) and Bowlegs Creek (300 feet each side).
6.1.11 MAKE EFFORTS TO PRESERVE ARCHAEOLOGICAL OR HISTORICAL SITES THROUGH
AVOIDANCE OR MITIGATE BY SALVAGE EXCAVATION PERFORMED BY A PROFES-
SIONALLY COMPETENT AGENCY ANY SITES DEEMED SIGNIFICANT BY THE
FLORIDA DIVISION OF ARCHIVES, HISTORY, AND RECORDS MANAGEMENT. IF
MITIGATION IS CHOSEN, THE RESULTING REPORT SHOULD BE SUBMITTED TO
THAT STATE AGENCY FOR EXAMINATION AND COMMENT
An archaeological and historical survey of the Mobil site was conducted and
the results were submitted to the Florida Division of Archives, History and
Records Management. It was the opinion of this agency that the archaeological
and historical resources on the site did not merit any further mitigative or
preservation measures.
6-11
-------
6.2 REFERENCES
Cowardin, L.M., V. Carter, F.C. Golef, and E.T. LaRue. 1977. Classification
of Wetlands and Deepwater Habitats of the United States. Operational
Draft, U.S. Fish and Wildlife Service.
Reppert, R.T., W. Sigleo, E. Stakhiv, L. Messman, and D. Meyers. 1979.
Wetland Values: Concepts and Methods for Wetland Evaluation. IWR
Research Report 79-R1. U.S. Army Engr. Inst. for Water. Res. Kingman
Bid., Ft. Belvoir, Va.
U.S. Army Corps of Engineers. 1978. Preliminary Guide to Wetlands of
Peninsular Florida. Major Associations and Communities Identified.
Technical Report Y-28-2. Environmental Effects Lab., Vicksburg, Miss.
U.S. Environmental Protection Agency. 1978. Final Environmental Impact
Statement for the Central Florida Phosphate industry. EPA 904/9-78-026a.
U.S. Environmental Protection Agency. 1979. Indoor Radiation Exposure due to
Radium-226 in Florida Phosphate Lands. Office of Radiation Programs,
Washington, D.C. EPA 520/4-78-013.
6-12
-------
7.0 COORDINATION
7.1
DRAFT ENVIRONMENTAL IMPACT STATEMENT COORDINATION LIST
The following Federal, state and local agencies, public officials, organiza-
tions, and interest groups have been requested to comment on this impact
statement.
Federal Agencies
Bureau of Outdoor Recreation
Bureau of Mines
Coast Guard
Corps of Engineers
Council on Environmental Quality
Department of Agriculture
Department of Commerce
Department of Education
Department of Interior
Department of Transportation
Department of Health and Human
Services
Department of Housing and Urban
Development
Department of Energy
Federal Highway Administration
Fish and Wildlife Service
Food and Drug Administration
Forest Service
Geological Survey
National Park Service
Economic Development Administration
Soil Conservation Service
Public Health Service
Members of Congress
Honorable Lawton Chiles
United States Senate
Honorable Sam Gibbons
U.S. House of Representatives
Honorable L.A. Bafalis
U.S. House of Representatives
Honorable Paula Hawkins
United States Senate
Honorable Andy P. Ireland
U.S. House of Representatives
7-1
-------
State of Florida
Honorable D. Robert Graham
Governor
Coastal Coordinating Council
Department of Natural Resources
Department of Agriculture and
Consumer Services
Department of Community Affairs
Geological Survey
Game and Freshwater Fish
Commission
Department of Administration
Department of State
Environmental Regulation Committee
Department of Commerce
Department of Health and
Rehabilitative Services
Bureau of Intergovernmental
Relations
Department of Environmental
Regulation
Department of Transportation
Local and Regional
Polk County Commission
Manatee County Commission
DeSoto County Commission
Hardee County Commission
Polk County Building & Zoning
Department
Tampa Bay Regional Planning
Council
Central Florida Regional
Planning Council
Southwest Florida Water
Management District
Interest Groups
The Fertilizer Institute
Florida Phosphate Council
Florida Audubon Society
Florida Sierra Club
Manasota 88
Florida Defenders of the
Environment
Izaak Walton League of
America
Florida Wildlife Federation
7.2
PUBLIC PARTICIPATION AND SCOPING
On October 16, 1979, EPA published in the Federal Register a Notice of Intent
to prepare an EIS for the proposed project, and announced a public meeting for
the purpose of defining the scope of the EIS and identifying the primary
7-2
-------
and secondary issues to be addressed in the Plan of Study for the EIS. The
scoping meeting was held by EPA in Mulberry, Florida on November 28, 1979. The
attendence of sixteen was largely comprised of members of the phosphate indus-
try and representatives of consulting firms. Agencies represented were the
Southwest Florida Water Management District (SWFWMD), the Florida Department
of Transportation, the Florida Department of Agriculture, Division of Fores-
try, and the Polk County Building and Zoning Codes Department. Mr. John Heuer
of SWFWMD briefly reviewed the SWFWMD procedures and emphasized that although
groundwater withdrawals are under SWFWMD jurisdiction, groundwater consumption
is a major issue with the phosphate industry and should be addressed in the
EIS. Mr. D. Millard of the Forestry Service noted that projects were underway
to determine the best tree species for reforesting reclaimed land. He indi-
cated that the Forestry Service would prefer to see reclamation which en-
courages agricultural uses with an emphasis on forestry. These comments were
considered in the preparation of the EIS.
7.3 CONSULTATION WITH THE U.S. DEPARTMENT OF INTERIOR
EPA has performed all consultation procedures in accordance with the require-
ments of Section 7 of the Endangered Species Act of 1973, as amended. On
December 12, 1980, EPA provided the U.S. Department of Interior, Fish and Wild-
life Service (USF&WS) with a description of the proposed Mobil project and
requested that a list of endangered and/or threatened species which may occur
in the project's area of influence be provided to EPA (EPA, 1980a). On
December 18, 1980, the USF&WS commented that two endangered species, the bald
eagle and the red-cockaded woodpecker, and two threatened species, the
American alligator and the eastern indigo snake, may be present in the area
(USF&WS, 1980).
On May 19, 1981, EPA provided USF&WS with a Biological Assessment of the im-
pacts of the Mobil project on endangered or threatened species as required by
Section 7 (c) of the Endangered Species Act (EPA, 1981a).
7-3
-------
EPA indicated that after reviewing the Biological Assessment, it was EPA's
determination that the proposed Federal action (i.e., issuance of an NPDES
permit for the proposed project) might affect the threatened eastern indigo
snake. Therefore, EPA officially requested that Section 7 consultation pro-
cedures be initiated. EPA also suggested in the May 19 letter that a capture
and relocation program could be implemented to mitigate possible impacts on
the species.
On May 29, 1981, EPA received information from USF&Wb that a few individuals
of an additional listed species, the endangered bald eagle, might be affected
by the proposed project. An active eagle nest had been recently located on
property adjacent to Mobil's proposed mine, approximately one-quarter mile
from the mine boundary at the closest point (Figure 7.^-A). Both the USF&WS
and the Florida Endangered Species Coordinator were concerned that the eagles'
feeding area, believed to be on the adjacent Mobil property, be maintained.
By correspondence dated June 5, and July 16, 1981, EPA suggested further
mitigative measures for the protection of the eagles (EPA, 1981b and EPA,
1981c).
The USF&WS provided a Biological Opinion on the project to EPA on August 18,
1981 (USF&WS, 1981). The Biological Opinion stated that the proposed action
is not likely to jeopardize the continued existence of the bald eagle, eastern
indigo snake, red-cockaded woodpecker and American alligator. They did, how-
ever, make recommendations for preservation of the indigo snake and the bald
eagle. These recommendations have been incorporated as conditions of the pro-
posed NPDES permit.
7.4 CONSULTATION WITH THE STATE HISTORIC PRESERVATION OFFICER
EPA has carried out all consultation requirements established by Section 106
of the National Historic Preservation Act of 1966. On July 23, 1980, EPA pro-
vided the State Historic Preservation Officer (SHPO), Florida Department of
State, Division of Archives, History and Records Management, with a descrip-
tion of the proposed Mobil project and a Cultural Resources Assessment of
the South Fort Meade Mine site (EPA, 1980b) pursuant to the procedures for
consultation and comment promulgated by the Advisory Council on Historic
7-4
-------
LOCATION OF EAGLE'S NEST
1MILE
LEGEND
(l>) EAGLE'S NEST
n
SOURCE: FISH & WILDLIFE SERVICE
-------
Preservation in 36CFR Part 800. On December 16, 1980, the SHPO replied to the
EPA request by stating that it is unlikely that the Mobil project will affect
any archaeological or historic sites listed or eligible tor listing in the
National Register of Historic Places, or otherwise of national, state, or
local significance (Percy, 1980).
7.5 COORDINATION WITH THE U.S. ARMY CORPS OF ENGINEERS
Wetlands on Mobil's South Fort Meaae site fall under the jurisdiction of the
U.S. Army Corps of Engineers, and the execution of the proposed project in
those areas will require a Section 404 (Federal Water Pollution Control Act)
permit from the Corps. In view of the Corps' responsibility in this area,
EPA has coordinated closely with them in the preparation of this EIS. On
November 21, 1979, EPA, the Corps and Mobil executed a joint Memorandum of
Understanding which established EPA as the lead agency and the Corps as a co-
operating agency in preparing the EIS. The Corps was subsequently provided
the opportunity for review and comment on the Plan of Study and on all work per-
formed by the third party consultant including the Preliminary Draft EIS. In
commenting to EPA on the Preliminary DEIS (Sanders, 1981), the Corps stated
that although they continue to disagree with EPA's practice of categorization
of wetlands, their review of the document revealed that sufficient factual
information is presented to identify areas of importance comprising those wet-
lands subject to Department of Army Regulatory authority. The Corps advised
that they will make their permit determination on the basis of the information
provided in the DEIS, information obtained through their public review pro-
cess, and requisites of their current regulations.
7.6 COORDINATION WITH THE U.S. DEPARTMENT OF INTERIOR. BUREAU OF LAND
MANAGEMENT
The Bureau of Land Management (BLM) has retained, through patent reservations,
the phosphates under approximately 8,000 acres in the central Florida phos-
phate area. These Federally owned reserves are scattered over a large area in
moderately sized parcels which usually do not form contiguous blocks of land
greater than 400 acres. They may be leased from the BLM in accordance with 43
CFR, Group 3500 (Leasing of Minerals Other than Oil and Gas).
7-6
-------
With the exception of the outparcels indicated, Mobil is the surface-owner of
all the property within the mine boundary as depicted on Figure 1.0-B, Page
1-3. Mobil also owns the phosphate under those same lands with the important
exception of four parcels totalling approximately 880 acres as shown on Figure
7.6-A. The phosphate minerals under those 880 acres are BLM Mineral Reserves,
and in order to mine them Mobil must obtain a competitive phosphate lease from
BLM.
EPA was not informed by Mobil of their lack of phosphate mineral rights to any
lands included in the South Fort Meade Mine site, and the scoping process
carried out in October and November of 1979 failed to identify BLM's role in
the proposed mine. On March 7, 1980, Mobil submitted four applications to BLM
for competitive phosphate leases on a total of 1,445 acres of land in Polk and
Hardee Counties, including the 880 acres within the South Fort Meade Mine
site. This action was brought to EPA's attention by the BLM Eastern States
Office on July 20, 1981 (BLM, 1981a).
By definition (40 CFR Sec. 1508.25) the proposed phosphate lease for those 880
acres would have been a "connected action" within the scope of EPA's envi-
ronmental impact statement for the proposed mine. Therefore, on July 31, 1981,
in accordance with 40 CFR Sec 1501 (1) (c). EPA requested BLM to participate
as a cooperating agency with EPA as lead agency in preparing the EIS for
Mobil's proposed South Fort Meade phosphate mine (EPA, 1981d). Specifically,
EPA proposed that the EIS be used by BLM to meet their information needs for a
decision on those lease lands contained within the boundary of the proposed
mine addressed by the EIS. On August 28, 1980, the Eastern State Office of
BLM confirmed the lead agency/cooperating agency relationship proposed by EPA
for the Mobil EIS (BLM, 1981b).
7-7
-------
BUREAU OF LAND MANAGEMENT MINERAL RESERVES
OUfPARCElS IPHIVATtlY OWNED]
1 Ml. 1
DIM MINERAL
RESERVES
tT)
cr
70
n
i
i
-------
7.7 REFERENCES
Bureau of Land Management. 1981a. Letter from Roger L. Hildebeidel, Eastern
States Office Alexandria, Virginia, to Rebecca W. Hanmer, U.S. EPA Region
IV, July 20, 1981.
Bureau of Land Management. 1981b. Letter from Roger L. Hildebeidel,
Eastern States Office, Alexandria, Virginia to Charles R. Jeter,
U.S. EPA Region IV, August 28, 1981.
Percy, G.W. 1980. Letter from George W. Percy, Deputy State Historic Pre-
servation Officer, to A. Jean Tolman, U.S. EPA Region IV, December 16, 1980.
Saunders, L.H. 1981. Letter from Lloyd H. Saunders, Acting Chief, Planning
Division, Jacksonville District, Corps of Engineers, to A. Jean Tolman, U.S.
EPA Region IV, July 17, 1981.
U.S. Environmental Protection Agency. 1980a. Letter from A. Jean Tolman,
U.S. EPA Region IV, to Don Palmer, U.S. Fish and Wildlife Service,
Jacksonville, Florida, December 12, 1980.
U.S. Environmental Protection Agency. 1980b. Letter from A. Jean Tolman, U.S.
EPA Region IV, to G.W. Percy, Deputy State Historic Preservation Officer,
July 23, 1980.
U.S. Environmental Protection Agency. 1981a. Letter from A. Jean Tolman,
U.S. EPA Region IV, to Donald Hankla, U.S. Fish and Wildlife Service,
Jacksonville, Florida, May 19, 1980.
U.S. Environmental Protection Agency. 1981b. Letter from A. Jean Tolman,
U.S. EPA Region IV, to Don Palmer, U.S. Fish and Wildlife Service,
Jacksonville, Florida, June 5, 1981.
U.S. Environmental Protection Agency. 1981c. Letter from A. Jean Tolman,
U.S. EPA Region IV, to Don Palmer, U.S. Fish and Wildlife Service,
Jacksonville, Florida, July 16, 1981.
U.S. Environmental Protection Agency. 1981d. Letter from Charles R. Jeter,
"u.S. EPA Region IV, to Roger L. Hildebeidel, Bureau of Land Management,
Eastern States Office, Alexandria, Virginia, July 31, 1981.
U.S. Fish and Wildlife Service. 1980. Letter from Donald J. Hankla,
*U*S Fish and Wildlife Service Jacksonville, Florida, to A. Jean
Tolman, U.S. EPA Region IV, December 18, 1980.
U.S. Fish and Wildlife Service. 1981. Letter from Donald J. Hankla,
*u!s. Fish and Wildlife Service Jacksonville, Florida, to A. Jean
Tolman, U.S. EPA Region IV, August 18, 1981.
7-9
-------
8.0 LIST OF PREPARERS
The following EPA officials participated in developing this DEIS.
Name Responsibility
Robert B. Howard Chief, EIS Preparation Section
A. Jean Tolman EIS Project Officer
Lionel Alexander, III NPDES Permit Coordinator
D. Brian Mitchell Air Quality
Louis Nagler Air Quality
Doyle Brittain Air Quality
James E. Orban Noise
A. Eugene Coker Geology and Groundwater
H. Richard Payne Radiation
Curtis F. Fehn Groundwater
Thomas R. Cavinder Surface Water
John T, Marlar Surface Water
William L. Kruczynski Biology and Ecology
Delbert B. Hicks Biology and Ecology
For information on the material presented in this section, contact A. Jean
Tolman at (404) 881-7458 (FTS/257-7458).
The Draft EIS for the Mobil South Fort Meade project was prepared by EPA with
consultant assistance from Engineering-Science, Inc. (ES) of Atlanta, Georgia,
using the third party EIS preparation method. The names and qualifications of
the ES project team on this EIS are presented in Table 8.0-1. Data presented
in the Draft EIS were gathered as a joint effort by the U.S. Environmental
Protection Agency, Mobil Chemical Company, and the consultants listed in Table
8.0-2. ES was responsible for evaluating the plans and quality assurance
provisions of the data gathering consultants. The data was provided to ES in
an uninterpreted form.
8-1
-------
TABLE 8.0-1
NAMES, RESPONSIBILITIES, AND QUALIFICATIONS OF PERSONS
PRIMARILY RESPONSIBLE FOR PREPARING THE MOBIL DRAFT
ENVIRONMENTAL IMPACT STATEMENT
Name
Andrew W. Loven
Responsifaility
Principal-in-Charge
Thonas N. Sargent Project Director
Ernest J. Schroeder Project Manager
Briar D. Moreth
Deputy Project Manager
j. Kenneth Allison Air Quality, Meteorology
Fran* R. Cruro
Geology and Groundwater
Earnest F. Gloyna Radiation
Ben;iman W. Breedlove Biology
Lial F. Tischler
T.H. Gurr
Surface Mater
Radiation
Reclamation and Mine
Plan Evaluation
Stephen C. Heeley Human Resources
9>jth i. Mac!i
Editor
Qua1, ifications
Ph.D. Physical Chemistry; Principal and Senior
Vice President, Engineering-Science, Inc.. 21
years experience including the direction of inter-
discipline studies for environmental assessments
and industrial facility siting studies.
M.S. Environmental Engineering; Associate and
Manager of Engineering Development, Engineering-
Science, Inc., 14 years experience in the
direction of interdiscipline studies with emphasis
in environmental studies and permit preparation.
M.S. Civil Environmental Engineering; Associate,
Engineering-Science, Inc., 14 years experience in
environmental studies with emphasis in plant
siting and development of pollution abatement
programs for industrial facilities.
B.S. Forest Science and B.S. Zoology; Project
Scientist, Engineering-Science, Inc., 10 years
experience in the preparation of environmental
impact statements for a wide variety of projects
including phosphate mines.
M.S. Meteorology; Senior Meteorologist/Scientist,
Engineering-Science, Inc., 28 years experience in
environmental studies including meteorology, air
quality and air diffusion including impact
studies.
B.S. Geology; Vice President and Director.
Leggette, Brashears and Graham, Inc., 22 years
experience in geological investigations and
groundwater studies for projects including
phosphate mining operations investigations.
Dr. Eng. Sanitary Engineering and Mater Resources;
Special Consultant, Engineering-Science, Inc., 35
years experience in waste management including
radioactive waste disposal consulting with
National Academy of Sciences.
M.S.P.H. Public Health and Environmental Biology;
Principal, Breedlove Associates, Inc., 12 years
experience in biological research studies in-
cluding aquatic ecology, "imnology, terrestrial
ecology, water quality evaluations and ecosystem
analyses.
Ph.D. Civil (Environmental Health) Engineering;
Principal and Vice President, Engineering-Science,
Inc., 17 years experience in water quality
modeling and impact assessment, evaluation of
radiological health impacts.
M.A., Geology; Associate Scientist, Dames and
Moore, 15 years experience in geological and
mining studies in the Central Florida Phosphate
District including mine planning, explanation,
reclamation economic geology and environmental
permitting.
B.L.S. Environmental Management; Staff Scientist,
Engineering-Science, Inc., 1 years experience in
socio-economic (human resources) analyses prep-
aration as part of comprehensive environmental
studies.
B.A. English; Editor, Engineering-Science, Inc.,
3 years experience editing reports, manuals, and
selected publications.
8-2
-------
TABLE 8.0-2
ORGANIZATIONS RESPONSIBLE FOR GATHERING
THE BASIC DATA USED IN PREPARING
THE MOBIL DRAFT ENVIRONMENTAL IMPACT STATEMENT*
AREA(S) OF
ORGANIZATION RESPONSIBILITY
Dames & Moore Surface Water
Lakeland, FL Soils and Geology
Geraghty & Miller, Inc. Groundwater
Tampa, FL
Post, Buckley, Schuh & Oernigan Groundwater
Orlando, FL Radiation
NUS Corporation Human Resources
Rockville, MD Archaeology
Water and Air Research, Inc. Biology
Gainesville, FL
Zellars-Williams, Inc. Soils and Geology
Lakeland, FL
Environmental Science and Engineering, Inc. Air
Gainesville, FL
*The data gathering effort was overseen by Engineering-Science, Inc. of Atlanta,
Georgia, the third party consultant working under contract to the U.S.
Environmental Protection Agency.
8-3
-------
INDEX
-------
INDEX
Air Quality
Regulations: 3-5
Pollutants: 3-7, 11; 4-1
Alternatives (See Following Listings)
Environmentally Preferred
EPA's Preferred
Matrix Processing
Matrix Transfer
Mining
No Action
Plant Siting
Product Transport
Reclamation
Waste Disposal
Water Discharge
Water Sources
Agricultural Resources: 2-106; 3-31, 127, 139; 4-5
Aquifers
Lower Floridan: 3-71, 74, 75, 76; 4-2; 5-4
Surficial: 3-69, 72, 74; 4-3
Upper Floridan: 3-69, 72
Biology
Land Communities: 3-120, 136; 4-4; 5-4; 6-6
Land-Water Interface: 3-123, 138; 4-4; 5-4; 6-6
Water Communities: 3-124, 138; 4-4; 5-5; 6-6
Chemicals and Reagents: 2-31; 3-101; 5-3
Dikes: 2-7, 35, 44, 51, 62, 63; 3-103, 104, 105, 144
Energy: 2-18, 23, 31
Environmentally Preferred: 2-23, 26, 34, 65, 106, 113, 114, 116, 118,
124; 6-7
EPA's Preferred: 2-124; 6-7
Forest Resources: 3-127, 139
Geology
Geomorphology: 3-18
Mine Site Geology: 3-20, 28; 4-2; 5-1
Solution Features: 3-18
Stratigraphy: 3-18
Groundwater
Quality: 3-47, 72
1-1
-------
Quantity: 3-69; 4-2; 5-4; 6-3
System: 2-120; 3-67
Historical and Archaeo-
logical Resources: 3-156, 162; 4-5; 5-7; 6-11; 7-4
Human Resources
Community Services: 3-157
Demographics and Economics: 3-155, 161; 4-5
Land Use: 2-106; 3-157, 162
Transportation: 3-158, 165
Leach Zone Management: 2-16, 124; 3-28
Matrix Processing
Conventional: 2-27; 3-14, 29, 50, 76, 101
Dry Separation: 2-33; 3-15, 29, 51, 79, 102
Matrix Transfer
Conveyor: 2-24; 3-13, 76, 101, 144
Pipeline: 2-23; 3-13, 76, 101, 144
Truck: 2-26; 3-13, 76, 101, 144
Meteorology: 3-2
Migratory Wildlife
and Game Species: 3-128, 139
Mining Method
Bucketwheel: 2-20; 3-12, 28, 49, 75, 99, 143
Dragline: 2-18; 3-11, 28, 49, 74, 98, 136
Dredge: 2-21; 3-12, 29, 50, 75, 99, 143
Mitigation Measures: 2-15, 118
Mobil's Proposed Action
Matrix Processing: 2-6, 27
Matrix Transfer: 2-6, 23
Mining Method: 2-2, 18
Mitigation Measures: 2-15
Plant Siting: 2-9, 113
Product Transport: 2-15, 117
Reclamation: 2-7, 65
Waste Disposal: 2-7, 35
Water Discharge: 2-9, 115
Water Sources: 2-9, 111
No Action Alternative: 2-120; 3-11, 28, 48, 74, 98, 135, 160
Noise: 3-9, 11
Plant Siting
Gilshey Branch: 2-113; 3-17, 153
On-Site Locations: 2-114; 3-17, 153
1-2
-------
Preserved Areas: 2-2, 5; 3-138, 141, 143; 4-4
Product Transport
Railroad: 2-117; 3-17, 67, 117, 154, 166
Truck: 2-117; 3-17, 67, 117, 154, 166
Radiation
Exposure: 3-40, 53; 4-2; 6-4
Phosphate Deposits: 3-41
Uptake: 3-48
Rare and Endangered Species
Federal: 2-118; 3-128, 140; 7-3
State: 3-129, 141
Reclamation
Conventional Plan: 2-65; 3-15, 31, 53, 82, 105, 148, 162
Overburden/Clay Mix Plan: 2-103; 3-16, 38, 64, 85, 111, 152, 163
Sand/Clay Cap Plan: 2-80; 3-16, 34, 58, 83, 108, 151, 163
Sand/Clay Mix Plan: 2-92; 3-16, 36, 61, 84, 108, 152, 163
Soils
Associations: 3-25
Series: 3-20, 28
Unique Agricultural Lands: 3-25
Streams & Rivers
Bowlegs Creek: 2-2; 3-90, 116, 126; 4-3
On-Site Tributaries: 3-95, 126; 4-3
Peace River: 3-86, 90, 112, 125; 4-3
Surface Water
Quality: 3-47, 90; 4-3; 6-1
Quantity: 3-90; 4-3
Utilization: 3-95, 112
WdStConven?ional Case: 2-35; 3-15, 29, 53, 79 103,,144
Overburden/Clay Mix Case: 2-58; 3-16, 31. 64 81, 105 148
Sand/Clay Cap Case: 2-44, 80; 3-16, 30, 58, 80, 104, 147
Sand/Clay Mix Case: 2-50; 3-16, 30, 61, 80, 104, 147
Water Discharge
Peace River: 2-115; 3-112, 154
Bowlegs Creek: 2-115; 3-116, 154
Water Sources
Groundwater: 2-111; 3-39, 85, 111, 153
Surface Water: 2-112; 3-39, 86, 112, 153
Wetlands: 2-119; 3-131, 142;
1-3
-------
APPENDIX
DRAFT NPDES PERMIT
-------
Permit Ho.: FL0037958
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IV
349 COURTLAND STRCET
ATLANTA. GEORGIA J0345
AUTHORIZATION TO DISCHARGE UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMLNATION SYSTEM
In compliance with the provisions of the Clean Water Act, as amended
(33 C.S.C. 1251 et. seq; the "Act"),
Mobil Chemical Co. - South Fort Meade Mine
is authorized to discharge from a facility located at
Latitude - 27° 39* 26"
o ' "
Longitude - 81 46 08
DRAFT
to receiving waters named
The Peace River
in accordance with effluent limitations, monitoring requirements and
other conditions set forth in Parts I, II, and III hereof. The permit
consists of this cover sheet, Part I 3 pages(s), Part II 12 page(s)
and Part III 6 page(s).
This permit shall become effective on
This permit and the authorization to discharge shall expire at
midnight,
Date Signed Howard D. Zeller
Acting Director
Enforcement Division
A-l
-------
A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
During the period beginning on the effective date of this permit and lasting through the term of this permit,
the permittee is authorized to discharge from outfall(s) serial number(s) 001 - process generated waatewater.
Such discharge! shall be limited and monitored by the permittee as specified below:
Effluent Characteristic
Flow-m3/Day (MOD)
Total Suspended
Solids
Specific Conductance
Radium*
Discharge Limitations Monitoring Requirement*
kg/day (Ibs/day) QtRer Unite (Specify)
Measurement Sample
Daily Avg Daily Max Daily Avg Daily Max Frequency Type
(during discharge)
~ Continuous** Recorder
30 mg/1 60 tng/1 I/week Composite
550 ymhos/cm 1000 jimhos/cm I/week Composite
5 pci/1 10 pci/1 I/week Composite
*Corabined Radium 226 & 228
The pH shall not be less than 6.0 standard units nor greater than 8.5 standard units and shall be monitored once per
week with a grab sample.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Samples taken in compliance with the monitoring requirements specified above shall be taken at the following lor:iiion(s):
nearest accessible point after final treatment but prior to actual discharge or mixing with
the receiving waters.
Ł w >
3 TO a
K n _i
o
o
**The discharge flow shall not exceed 20 percent the flow in the Peace River.
Ul
00
-------
B. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
Any overflow from facilities designated, constructed and maintained to contain
or treat the volume of wastewater which would result from a "10-year, 24-hour
precipitation event shall not be subject to the suspended solids limitation
or the pH limitation listed on the proceeding pages. Monitoring and reporting
shall be required for all other parameters.
The effluent limits and any additional requirements specified in the state
certification supersede any less stringent effluent limits listed above. During
any time period in which more stringent state certification effluent limits are
stayed or inoperable, the effluent limits listed above shall be in effect and
fully enforceable.
3>
CO
a
H m T)
a PI >
H-OQ ?a
rt rt> H
a M i-1
o i
O
o
00
-------
PARTI
Page 1-3
Permit No. FL0037958
B. SCHEDULE OF COMPLIANCE
1. The permittee thall achieve compliance with the effluent limitations specified for
discharge* in accordance with the following schedule:
2. The permittee shall comply with the effluent limits by the
effective date of the permit.
2. No later than 14 calendar dayi following a date identified in the above schedule of
compliance, the permittee shall submit either a report of progress or, in the case of
specific action* being required by identified dates, a written notice of compliance or
noncompliance. In the latter case, the notice shall include the cause of noncompliance,
any remedial actions taken, and the probability of meeting the next scheduled
requirement.
A-4
-------
Part II
Page II-l
A. MANAGEMENT REQUIREMENTS
1. Discharge Violations
All discharges authorized herein shall be consistent with the terms
and conditions of this permit. The discharge of any pollutant more
frequently than, or at a level in excess of, that identified and
authorized by this permit constitutes a violation of the terms and
conditions of this permit. Such a violation may result in the
imposition of civil and/or criminal penalties as provided in Section
309 of the Act.
2. Change in Discharge
Any anticipated facility expansions, production increases, or process
modifications which will result in new, different, or increased
discharges of pollutants must be reported by submission of a new
NPDES application at least 180 days prior to commencement of such
discharge. Any other activity which would constitute cause for
modification or revocation and reissuance of this permit, as
described in Part II (B) (4) of this permit, shall be reported to the
Permit Issuing Authority.
3. Noncotnpliance Notification
a. Instances of noncompliance involving toxic or hazardous pollutants
should be reported as outlined in Condition 3c. All other instances
of noncompliance should be reported as described in Condition 3b.
b. If for any reason, the permittee does not comply with or will be
unable to comply with any discharge limitation specified in the
permit, the permittee shall provide the Permit Issuing Authority
with the following information at the time when the next Discharge
Monitoring Report is submitted.
(1) A description of the discharge and cause of noncompliance;
(2) The period of noncompliance, including exact dates and times
and/or anticipated time when the discharge will return to
compliance; and
(3) Steps taken tor reduce, eliminate, and prevent recurrence of
the noncomplying discharge.
A-5
-------
Part II
Page II-2
c. Toxic or hazardous discharges as defined below shall be reported
by telephone within 24 hours after permittee becomes aware of the
circumstances and followed up with information in writing as
set forth in Condition 3b. within 5 days, unless this requirement
is otherwise waived by the Permit Issuing Authority:
(1) Noncomplying discharges subject to any applicable toxic
pollutant effluent standard under Section 307(a) of the Act;
(2) Discharges which could constitute a threat to human health,
welfare or the environment. These include unusual or extra-
ordinary discharges such as those which could result from
bypasses, treatment failure or objectionable substances
passing through the treatment plant. These include Section
311 pollutants or pollutants which could cause a threat to
public drinking water supplies.
d. Nothing in this permit shall be construed to relieve the permittee
from civil or criminal penalties for noncompliance.
4. Facilities Operation
All waste collection and treatment facilities shall be operated in
a manner consistent with the following:
a. The facilities shall at all times be maintained in a good
working order and operated as efficiently as possible. This
includes but is not limited to effective performance based on
design facility removals, adequate funding, effective management,
adequate operator staffing and training, and adequate laboratory
and process controls (including appropriate quality assurance
procedures); and
b. Any maintenance of facilities, which might necessitate unavoidable
interruption of operation and degradation of effluent quality,
shall be scheduled during noncritical water quality periods and
carried out in a manner approved by the Permit Issuing Authority.
c. The permittee, in order to maintain compliance with this permit
shall control production and all discharges upon reduction, loss,
or failure of the treatment facility until the facility is
restored or an alternative method of treatment is provided.
5. Adverse Impact
The permittee shall take all reasonable steps to minimize any
adverse impact to waters of the United States resulting from
A-6
-------
Part II
Page II-3
noncompliance with any effluent limitations specified in this
'permit, including such accelerated or additional monitoring as
necessary to determine the nature of the noncomplying discharge.
6. Bypassing
"Bypassing" means the intentional diversion of untreated or partially
treated wastes to waters of the United States from any portion of a
treatment facility. Bypassing of wastewaters is prohibited unless
all of the following conditions are met:
a. The bypass is unavoidable-i.e. required to prevent loss of life,
personal injury or severe property damage;
b. There are no feasible alternatives such as use of auxiliary
treatment facilities, retention of untreated wastes, or
maintenance during normal periods of equipment down time;
c. The permittee reports (via telephone) to the Permit Issuing
Authority any unanticipated bypass within 24 hours after
becoming aware of it and follows up with written notification
in 5 days. Where the necessity of a bypass is known (or should
be known) in advance, prior notification shall be submitted to
the Permit Issuing Authority for approval at least 10 days
beforehand, if possible. All written notifications shall contain
information as required in Part II (A)(3)(b); and
d. The bypass is allowed under conditions determined to be necessary
by the Permit Issuing Authority to minimize any adverse effects.
The public shall be notified and given an opportunity to comment
on bypass incidents of significant duration to the extent
feasible.
This requirement is waived where infiltration/inflow analyses are
scheduled to be performed as part of an Environmental Protection
Agency facilities planning project.
7. Removed Substances
Solids, sludges, filter backwash, or other pollutants removed in
the course or treatment or control of wastewaters shall be disposed
of in a manner such as to prevent any pollutant from such materials
from entering waters of the United States.
A-7
-------
Part II
Page II-4
8. Power Failures
The permittee is responsible for maintaining adequate safeguards to
prevent the discharge of untreated or inadequately treated wastes
during electrical power failures either by means of alternate power
sources, standby generators or retention of inadequately treated
effluent. Should the treatment works not include the above
capabilities at time of permit issuance, the permittee must furnish
within six months to the Permit Issuing Authority, for approval, an
implementation schedule for their installation, or documentation
demonstrating that such measures are not necessary to prevent discharge
of untreated or inadequately treated wastes. Such documentation
shall include frequency and duration of power failures and an estimate
of retention capacity of untreated effluent.
9. Onshore or Offshore Construction
This permit does not authorize or approve the construction of any
onshore or offshore physical structures or facilities or the
undertaking of any work in any waters of the United States.
RESPONSIBILITIES
1. Right of Entry
The permittee shall allow the Permit Issuing Authority and/or
authorized representatives (upon presentation of credentials and
such other documents as may be required by law) to:
a. Enter upon the permittee's premises where an effluent source
is located or in which any records are required to be kept under
the terms and conditions of this permit;
b. Have access to and copy at reasonable times any records required
to be kept under the terms and conditions of this permit;
c. Inspect at reasonable times any monitoring equipment or
monitoring method required in this permit;
d. Inspect at reasonable times any collection, treatment, pollution
management or discharge facilities required under the permit; or
e. Sample at reasonable times any discharge of pollutants.
A-8
-------
Part II
Page II-5
2. Transfer of Ownership or Control
A permit may be transferred to another party under the following
conditions:
a. The permittee notifies the Permit Issuing Authority of the
proposed transfer;
b. A written agreement is submitted to the Permit Issuing Authority
containing the specific transfer date and acknowledgement that
the existing permittee is responsible for violations up to that
date and the new permittee liable thereafter.
Transfers are not effective if, within 30 days of receipt of proposal,
the Permit Issuing Authority disagrees and notifies the current
permitttee and the new permittee of the intent to modify, revoke and
reissue, or terminate the permit and to require that a new application
be filed.
3. Availability of Reports
Except for data determined to be confidential under Section 308
of the Act, (33 U.S.C. 1318) all reports prepared in accordance with
the terms of this permit shall be available for public inspection at
the offices of the State water pollution control agency and the Permit
Issuing Authority. As required by the Act, effluent data shall not
be considered confidential. Knowingly making any false statement on
any such report may result in the imposition of criminal penalties
as provided for in Section 309 of the Act (33 U.S.C. 1319).
4. Permit Modification
After notice and opportunity for a hearing, this permit may be modified,
terminated or revoked for cause (as described in 40 CFR 122.15 et seq)
including, but not limited to, the following:
a. Violation of any terms or conditions of this permit;
b. Obtaining this permit by misrepresentation or failure to
disclose fully all relevant facts;
c A change in any condition that requires either temporary
interruption or elimination of the permitted discharge; or
d Information newly acquired by the Agency indicating the
discharge poses a threat to human health or welfare.
A-9
-------
Part II
Page II-6
If the permittee believes that any past or planned activity would
be cause for modification or revocation and reissuance under
40 CFR 122.15 et seq, the permittee must report such information to
the Permit Issuing Authority. The submission of a new application
may be required of the permittee.
5. Toxic Pollutants
a. Notwithstanding Part II (B)(4) above, if a toxic effluent
standard or prohibition (including any schedule of compliance
specified in such effluent standard or prohibition) is established
under Section 307(a) of the Act for a toxic pollutant which is
present in the discharge authorized herein and such standard
or prohibition is more stringent than any limitation for such
pollutant in this permit, this permit shall be revoked and
reissued or modified in accordance with the toxic effluent
standard or prohibition and the permittee so notified.
b. An effluent standard established for a pollutant which is
injurious to human health is effective and enforceable by the
time set forth in the promulgated standard, even though this
permit has not as yet been modified as outlined in Condition 5a.
6. Civil and Criminal Liability
Except as provided in permit conditions on "Bypassing", Part II
(A) (6), nothing in this permit shall be construed to relieve the
permittee from civil or criminal penalties for noncorapliance.
7. Oil and Hazardous Substance Liability
Nothing in this permit shall be construed to preclude the
institution of any legal action or relieve the permittee from
any responsibilities, liabilities, or penalties to which the
permittee is or may be subject under Section 311 of the Act
(33 U.S.C. 1321).
8. State Laws
Nothing in this permit shall be construed to preclude the
institution of any legal action or relieve the permittee from
any responsibilities, liabilities, or penalties established
pursuant to any applicable State law or regulation under authority
preserved by Section 510 of the Act.
A-10
-------
Part II
Page II-7
Property Rights
The issuance of this permit does not convey any property rights in
either real or personal property, or any exclusive privileges, nor
does it authorize any injury to private property or any invasion of
personal rights, nor any infringement of Federal, State, or local
laws or regulations.
10. Severability
The provisions of this permit are severable, and if any provision
of this permit, or the application of any provision of this permit
to any circumstance, is held invalid, the application of such
provision to other circumstances, and the remainder of this permit
shall not be affected thereby.
11. Permit Continuation
A new application shall be submitted at least 180 days before the
expiration date of this permit. Where EPA is the Permit Issuing
Authority, the terms and conditions of this permit are automatically
continued in accordance with 40 CFR T22.5, provided that the permittee
has submitted a timely and sufficient application for a renewal permit
and the Permit Issuing Authority is unable through no fault of the
permittee to issue a new permit before the expiration date.
C. MONITORING AND REPORTING
1. Representative Sampling
Samples and measurements taken as required herein shall be
representative of the volume and nature of the monitored discharge.
2. Reporting
Monitoring results obtained during each calendar month shall be
summarized for each month and reported on a Discharge Monitoring
Report Form (EPA No. 3320-1). Forms shall be submitted at the end
of each calendar quarter and shall be postmarked no later than the
28th day of the month following the end of the quarter. The first
report is due by the 28th day of the month following the first full
quarter after the effective date of this permit.
A-ll
-------
Part II
Page II-8
Signed copies of these, and all other reports required herein, shall
be submitted to the Permit Issuing Authority at the following
address(es):
Permit Compliance Branch Florida Department of Environmenta
Environmental Protection Agency Regulation
Region IV Division of Environmental Programs
345 Courtland Street, N.E. Twin Towers Office Building
Atlanta, Georgia 30365 2600 Blair Stone Road
Tallahassee, Florida 32301
3. Test Procedures
Test procedures for the analysis of pollutants shall conform to all
regulations published pursuant to Section 304(h) of the Clean Water
Act, as amended (40 CFR 136, "Guidelines Establishing Test Procedures
for the Analysis of Pollutants").
4. Recording of Results
For each measurement or sample taken pursuant to the requirements
of this permit, the permittee shall record the following information:
a. The exact place, date, and time of sampling;
b. The person(s) who obtained the samples or measurements;
c. The dates the analyses were performed;
d. The person(s) who performed the analyses;
e. The analytical techniques or methods used; and
f. The results of all required analyses.
5. Additional Monitoring by Permittee
If the permittee monitors any pollutant at the location(s)
designated herein more frequently than required by this permit,
using approved analytical methods as specified above, the results
of such monitoring shall be included in the calculation and reporting
of the values required in the Discharge Monitoring Report Form
(EPA No. 3320-1). Such increased frequency shall also be indicated.
A-12
-------
Part II
Page 11-11
5. Other Measurements
a. The effluent flow expressed as M-Vday (MGD) is the 24 hour
average flow averaged monthly. It is the arithmetic mean of
the total daily flows recorded during the calendar month.
Where monitoring requirements for flow are specified in Part I
of the permit the flow rate values are reported in the "Average"
column under "Quantity" on the DMR.
b. Where monitoring requirements for pH, dissolved oxygen or fecal
coliform are specified in Part I of the permit the values are
generally reported in the "Quality or Concentration" column on
the DMR.
6. Types of Samples
a. Composite Sample - A "composite sample" is any of the following:
(1) Not less than four influent or effluent portions collected
at regular intervals over a period of 8 hours and composited
in proportion to flow.
(2) Not less than four equal volume influent or effluent
portions collected over a period of 8 hours at intervals
proportional to the flow.
(3) An influent or effluent portion collected continuously
over a period of 24 hours at a rate proportional to the flow.
b. Grab Sample: A "grab sample" is a single influent or effluent
portion which is not a composite sample. The sample(s) shall be
collected at the period(s) most representative of the total
discharge.
7. Calculation of Means
a Arithmetic Mean: The arithmetic mean of any set of values is
the summation of the individual values divided by the number
of individual values.
b Geometric Mean: The geometric mean of any set of values is the
Nth root of the product of the individual values where N is equal
t~the number of individual values. The geometric mean is
equivalent to the antilog of the arithmetic mean of the logarithms
of the individual values. For purposes of calculating the
geometric mean, values of zero (0) shall be considered to be one (1)
A-15
-------
Part II
Page 11-12
c. Weighted by Flow Value: Weighted by flow value means the
summation of each concentration times its respective flow
divided by the summation of the respective flows.
8. Calendar Day
a. A calendar day is defined as the period from midnight of one
day until midnight of the next day. However, for purposes of
this permit, any consecutive 24-hour period that reasonably
represents the calendar day may be used for sampling.
A-16
-------
Part III
Page III-l
Permit No. FL0037958
PART III
OTHER REQUIREMENTS
A. In accordance with Section 306(d) of the Federal Water Pollution
Control Act (PL 92-500) the standards of performance for conventional
Pollutions as contained in this permit shall not be made any more
stringent during a ten year period beginning on the date of completion
of construction or during the period of depreciation of amortization
of such facility for the purposes of Section 167 or 169 (or both) of
the Internal Revenue Code of 1954, whichever period ends first. The
provisions of Section 306(d) do not limit the authority of the
Environmental Protection Agency to modify the permit to require
compliance with a toxic effluent limitation. Promulgated under BAT
or Toxic Pollutant Standard established under Section 307(a) of the
FWPCA.
B. National Environmental Policy Act (NEPA) Requirements
The below listed requirements, conditions and limitations were
recommended in the site specific Environmental Impact Statement
for the Mobil Chemical Company South Fort Meade Mine, and are
hereby incorporated into National Pollutant Discharge
Elimination System Permit No. FL0037958 in accordance with 40
CFR 122.62(d)(9) .
1. Mobil shall employ the sand/clay cap waste disposal plan
and the sand/clay cap reclamation plan described in the EIS
and identified as EPA's preferred alternatives for waste
disposal and reclamation.
2. Mobil shall employ high profile overburden stacking in the
mining of the area covered by Clay Settling Area 10 (CS-10)
to the maximum extent compatible with toe spoiling of the
leach zone. If any increase in waste storage volume is
realized by the use of this technique, it shall be
reflected in a lower reclaimed elevation for the area
rather than an increase in clay storage within CS-10.
3. Mobil shall meet the requirements of its Southwest Florida
Water Management District (SWFWMD) Consumptive Use Permit.
4. Mobil shall provide storage that allows recirculation of
water recovered from slimes. The water circulation system
and storage capacity shall be as described in the EIS for
Mobil's proposed project.
A-17
-------
Part III
Page III-2
Permit No. FL00379
5. During the dragline mining activity, Mobil shall, in
accordance with its proposed action in the EIS, employ the
technique of leach zone management by toe spoiling, i.e.,
overburden from near the interface with the matrix shall be
placed at the toe of the spoil pile and covered with
overburden from upper strata.
6. Mobil shall meet county and state reclamation requirements.
7. Mobil shall preserve from mining, or any other disturbance
not essential to and unavoidable for the mining operation,
the areas designated for preservation in Mobil's proposed
action in the EIS. Specifically, the total of 1094 acres
thus preserved shall include a minimum of 182 acres of
cutover flatwoods, 664 acres of upland hardwood forest, 5
acres of upland mixed forest, 111 acres of freshwater
swamp, and 21 acres of freshwater marsh, all in the
locations depicted in the attached Figure 1.
8. Before beginning any land-disturbing activities, Mobil
shall develop a program whereby indigo snakes encountered
in the work area are captured and turned over to the FGFWFC
Endangered Species Coordinator for relocation to other
suitable habitats in the region. (The technique for
handling and keeping this species until the FGFWFC arrives
is to place the snake in a cloth sack, out of the sun,
preferably in an air conditioned building.) The program
shall include informing Mobil workers of the importance of
the indigo snake, familiarizing them with its appearance
and instructing them as to its preservation. In addition,
the gopher tortoise population in the site area shall be
protected to the extent possible. Mobil shall maintain a
record of the program to be submitted to the U.S. Fish and
Wildlife Service office in Jacksonville, Florida.
?. Mobil shall not conduct any mining, or any activity
associated with its mining operation, within 1500 feet in
any direction of the bald eagle nest located in T32S, R26E,
Section 9. Beginning four years prior to site preparation
activities preceding mining of the areas closest to the
eagle nest (to the east, south and west), Mobil shall
provide for a field study to be performed by a qualified
biologist to determine the area(s) being utilized for
feeding by the eagles. Observations shall be conducted
from January 1st through April 15 of the specified year.
Since young may or may not be produced in any given year,
Mobil shall attempt to provide data for at least one
successful nestling period during the referenced four
A-18
-------
Part III
Page III-3
Permit No. FL0037958
years. Specifics of the study shall be coordinated with
and reviewed by the USF&WS office in Jacksonville,
Florida. If it appears at the onset of the study year that
the subject eagle nest is no longer in existence, that fact
must be confirmed by a letter from the USF&rtS. If the
results of the study reveal that the eagles are utilizing
an area on the Mobil property for feeding, Mobil shall
preserve that area from disturbance.
10. Mobil shall comply with the categorization of wetlands
present on the mine property as set forth in the EIS and
illustrated in Figure 2, attached. In summary, within
Category 1 wetlands, Mobil shall not mine, shall limit
activities to those essential to and unavoidable for the
mining operation, and shall otherwise take all reasonable
measures to preserve all Category 1 wetlands. In addition,
Mobil shall restore the total acreage of Category 2
wetlands disturbed by mining.
11. Mobil shall conduct a monitoring program to assess the
wetlands restoration and re-creation effort at the South
Fort Meade Mine. Three wetland re-creation areas (a
depression wetland in area CS-1, the reforested stream
channel of Maron Run, and the forested wetland in area
CS-14) shall be monitored for one year according to the
following program: (1) Beginning 12 weeks after completion
of the reclamation of each respective area, the water level
shall be monitored biweekly; and (2) Following the first
full growing season, a biological assessment shall be
performed by a degreed biologist for each of the three
areas; the assessment shall include a listing of wetland
plant species present, mapping of their location, a visual
estimate of the amount of cover provided by the wetland
species, and sampling of the benthic macroinvertebrates to
yield a list of the species collected and their density.
After the above-described monitoring program is performed
for both the sand/clay depression area and the forested
stream channel, one area shall be selected by EPA for
long-term monitoring by Mobil. This long-term monitoring
program shall consist of a yearly biological assessment by
a degreed biologist to include the items in (2) above. In
addition, in order to determine the degree of subsidence
occurring, if any, the maximum depth of the marsh
depression area relative to a fixed elevation point shall
be monitored quarterly for the life of this permit. Mobil
shall submit annual reports of the described monitoring
program to the EPA Region IV Ecology Branch.
A-19
-------
Part III
Page IH-4
Permit No. FL0037958
12. During the raining activities conducted near the Bowlegs
Creek preserved area, Mobil shall monitor the Shallow
Aquifer to assess the effectiveness of the perimeter ditch
in preventing dewatering of the preserved area. This
monitoring program shall consist of using the existing well
#SA-3 to perform weekly manual water level measurements
during the first sixteen weeks of mining near Bowlegs Creek
and monthly thereafter until the mining pit immediately
adjacent to the preserved area is closed. Mobil shall not
allow the Shallow Aquifer in this preserved area to be
lowered more than three feet due to the mining activites.
13. Unless specified otherwise by a preceding condition in this
permit, Mobil shall perform its mining project in complete
accordance with the applicant's proposed action described
and evaluated in the Mobil South Fort Meade Mine EIS and
Supplemental Information Document (SID), including the
employment of all mitigating measures presented as part of
the proposed action. However, this shall not preclude the
imposition of any additional or more stringent conditions
which may be required by any local or state regulatory
agency or governmental entity.
A-20
-------
Figure 1
UNDISTURBED AREAS
T33S
SOURCE: ZELLARS-WILLIAMS
I mile
LEGEND
UNDISTURBED AREAS
WETLANDS TO REMAIN
UNDISTURBED
1 :
Pi
iq
a
I
-------
Figure 2
WETLAND DELINEATION MAP
PROPOSED SOUTH FORT MEADE MINE SfTE
MOBIL CHEMICAL COMPANY
EPA APPROVED - JUNE 2S.1MO
'*:
*
'4- ' h"
, ' .1 / . V
'
...
* ,
1 ' l"
, ^.p
L .,<.
.
,. /.
,. § -
1.ť.
' ' ..--- .
_ L" La' _ _l _ _ '_ _ _ -CV
! "
w
,.; vr'v--:..- :
b , - :; - ......
:.M. rf-
*
'Ť J*--
-^$8.% w> ^
* '' -
'.;
cu
TO
It
I
I
-------