United States Region 4 EPA 904/9-79-044
Environmental Protection 345 Courtland Street, NE October 1979
Agency Atlanta,GA 30308
v>EPA Environmental
Impact Statement DRAFT
Estech General Chemicals Corporation
Duette Mine
Manatee County, Florida
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EPA 904/9-79-044
NPDES Application Number:
FL0036609
DRAFT
ENVIRONMENTAL IMPACT STATEMENT
for
Proposed Issuance of a New Source National
Pollutant Discharge Elimination System Permit
to
Estech General Chemicals Corporation
Duette Mine
Manatee County, Florida
prepared for
U.S. Environmental Protection Agency
Region IV, Atlanta, Georgia 30308
Andrea E. Zimmer, Project Manager
by
Conservation Consultants, Inc.
Palmetto, Florida 33561
William W. Hamilton, III, Project Manager
Estech General Chemicals Corporation has proposed an open pit phosphate mine,
beneficiation plant and rock dryer on a 10,394 acre site in northeastern
Manatee County, Florida.
Mining will involve 6600 acres most of which will be reclaimed, and will pro-
duce 3 million tons per year for 21 years. The EIS examines alternatives,
impacts and mitigative measures related to surface water, groundwater, air,
wetlands, and other natural and cultural systems.
Comments will be received until November 30, 1979
Comments or inquiries should be directed to
John E. Hagan III
Chief, EIS Branch
U.S. Environmental Protection Agency
Region IV
345 Courtland Street, NE
Atlanta, Georgia 30308
(404) 881-7458
approved by:
r ./JV^A' ^ i ^4 - oct^m-.
-re
'r\f -»"•* C. White Date
Regional Administrator
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Summary Sheet For Environmental
Impact Statement
Duette Phosphate Mine
Estech General Chemicals Company
(X) Draft
( ) Final
U. S. Environmental Protection Agency, Region IV
345 Courtland Street NE
Atlanta, Georgia 30308
1. Type of Action : Administrative (X) Legislative ( )
2. Description of Action
Estech General Chemicals Corporation is proposing to construct
and operate a phosphate mine beneficiation plant, and rock drying
facility in northeastern Manatee 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 to the proposed
mining and beneficiation facility would constitute a major
Federal action significantly affecting the quality of the human
environment. Therefore, this Environmental Imapct Statement
was prepared in accordance with the requirements of NEPA and
EPA regulations at 40 CFR, Part 6.
The proposed facility, the Duette Mine, encompasses 10,394 acres
of which approximately 6,600 acres are deemed mineable
according to present economic, environmental and technological
limitations. The mining operation is planned to nominally
produce 3 million tons of phosphate ore annually for a period
of 21 years. Estech presently operates the Watson and Silver
City Mines in southwestern Polk County, Florida. The Duette
Mine will serve as a replacement for these facilities as their
production expires.
Components of the proposed facilities include two draglines with
50 cubic yard buckets; hydraulic ore transportation via pipelines
to a central washer for ore disaggregation and pebble recovery;
a feed preparation and flotation plant for extraction of finer
phosphates; a drying facility to reduce moisture in the phosphate
rock from 13% to 2%; and shipment via rail.
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Operation of the proposed facilities requires a mining plan,
a water management system, and an integrated waste disposal
reclamation plan.
The mining plan as proposed by Estech calls for the preservation
of the majority of the sensitive or unique natural vegetation.
The preservation areas include the sole cypress stand on the
site (18 acres), a 50 acre stand of sand pine scrub, and the
wooded floodplains of the major streams, with the exception of
a three-quarter mile segment of the East Fork Manatee River.
To protect wetlands along streams, the mine plan incorporates
active mining along only one side of a wetland at a time.
The proposed disposal plan will utilize a sand-clay mix in the
approximate ratio of 2.5 to 1 (by weight). A single 480 acre
conventional clay settling area is proposed to receive any clay
wastes in excess of the sand-clay mix requirements and to serve
as a supplemental water clarification and storage area. Sand
tailings in excess of the amounts required in the sand-clay mix
process will be deposited in mining cuts.
The proposed water management plan divides the needed supply
between surface and ground-water resources, minimizes mining
process consumption, and provides for recharge of the Floridan
Aquifer. The Consumptive Use Permit issued by the Southwest
Florida Water Management District allows ground-water withdrawal
at a rate of 13 mgd for the first 3 years. During this time,
a 200 acre surface water reservoir will be constructed to provide
storage for 3 mgd, thereby decreasing ground-water use to 10
mgd. Prior to withdrawal, a recharge system will be constructed
to transmit water from the surficial aquifer into the deep
s y s t em.
The proposed reclamation plan will be accomplished by the
physical restructuring and refilling of disturbed sites followed
by revegetation. The proposed methodology is designed to return
the site to land forms compatible with its rural, agricultural
setting. The reclaimed site will consist of improved pasture,
marsh and wetland environments, five lakes, and a 100 acre
"wilderness" area allowed to revegetate naturally. The proposed
plan aims to provide long range water quality and biological
diversity as well as aesthetic values in land form diversity,
wildlife protection, recreational uses, and water resources.
3. Alternatives Considered
A. Beneficiation plant sites were evaluated to minimize loss
of phosphate resource, water pumping, ore and waste
transportation, road and utility construction, and destruction
of environmentally sensitive areas. Six sites were considered.
B. Production rate alternatives were evaluated considering both
environmental and economic parameters. Environmental aspects
considered included rate of habitat alteration/destruction, rate
of ground-water withdrawal, and level of air emissions. Economic
considerations included production costs, overall rock demand
and growth, and Estech's present production and marketing.
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Alternatives were selected to evaluate the effects of various
production rates rather than to designate an optimum production
rate.
C. Resource recovery alternatives were evaluated with
consideration given to impacts on environmental resources and
recovery of mineral resources. The primary consideration was
phosphate ore underlying forested swamps or marsh areas.
D. Mining methods were evaluated to assess ore recovery rates,
energy use, water use and conservation, environmental resources,
and safety. Alternatives examined were electric draglines,
dredges, bucket wheel excavators, and technique combinations.
E. Ore transportation alternatives were evaluated considering
the factors of technical and operational feasibility, cost,
energy use, water conservation, and impact to the environment.
Conventional slurry pumping, conveyors, and trucks were
transportation methods considered.
F. Beneficiation process alternatives were evaluated for energy
and water use efficiencies within proven state-of-the-art
technology. Alternative processes considered were conventional
beneficiat ion, total acidulation, and blast furnace.
G. Process water sources were evaluated to conserve the regional
resource while providing a sufficient quality and quantity of
water. Supply alternatives considered were use of surface and
ground water, total requirement from the Floridan Aquifer, use
of surface water in rainfall catchment, and use of water from
the surficial aquifer.
H. Waste disposal and reclamation plans were evaluated for
methods to dispose of sand and clay wastes in a manner that
economically restores disturbed land to a productive state.
Physical restoration and revegetation were considered in light
of existing and planned environmental systems.
I. Surface water discharge alternatives were evaluated from
two respects: volume of water discharges and point of discharge.
Volume alternatives considered containment of long term
accumulation, containment of short term accumulation, containment
to offset evaporation losses only, and no containment. Eight
points of discharge were evaluated. Each alternative was
discussed in terms of environmental impacts, water use and
economi cs.
J. Rock drying alternatives were evaluated to select an
alternative which provided dry rock for shipping and met air
quality standards. Alternatives assessed were construction of
a dryer at the mine site, use of an existing dryer, construction
of a dryer at a remote location, and shipment of wet rock.
K. Transportation and energy source alternatives were evaluated.
Transportation alternatives included railroad with truck as
emergency mode, trucks only, pipeline to port, and conveyor.
Energy source alternatives assessed were conrmer ci al 1 y available
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electric power and various methods of on-site generation.
L. A no-action alternative was evaluated considering
environmental and socioeconomic impacts of not constructing the
mine, beneficiation plant, or rock drying facility.
4. Sum-nary of Major Environmental Effects
Each of the selected alternatives was integrated into the
appropriate land or water management strategy: the mining plan,
waste disposal/reclamation plan, and water management plan,
collectively the proposed activity. Environmental impacts of
the proposed activity were then assessed. The major emphasis
of the impact assessment was to identify means of minimizing
the degree and extent of negative impacts caused by the mining
operation at any one time and to minimize the permanent
alteration and/or destruction of natural systems and
environmental resources.
The direct effect of mining will be the physical destruction
of much of the present natural vegetation and the alteration
of the site's soils and topography. The proposed reclamation
plan is intended to mitigate the long-term negative impacts of
the minig operation. Major impacts to three major systems are
as foilows:
Land - Overall, 85% of the native upland vegetation will be lost.
Reclamation is designed to replace most natural land
communities with improved pasture, thereby largely
precluding the re-establishment of original vegetation.
A 50 acre stand of sand pine scrub is marked for
preser vat i on.
Land-Water Interface - Mining will destroy at least 476 acres
of fresh water swamps and 364 acres of fresh water
marshes. Proposed reclamation will restore these acreages
and contribute additional acres for a net gain of 15% in
land-water interface. The sole cypress stand (18 acres)
on the site will be preserved.
Water - The direct impact of mining will be the destruction of
417 acres of ephimeral feeder streams and their
floodplains. The remaining aquatic areas will suffer
stress resulting from changes in temperature, sunlight,
erosion, water table drawdown, and addition of various
chemicals. The wooded floodplains of the major streams
are excluded from mining, with the exception of a three
quarter mile segment of the East Fork Manatee River which
is proposed for mining and subsequent reclamation as a
swamp.
Mining will create several lakes on the site, which is
a significant expansion of the aquatic environment.
The proposed activity will significantly alter the site's
original topography through strip mining and waste clay disposal
activities. The long-term, net effects on topography are
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directly reflected in the proposed reclamation, which largely
returns the site to pre-mining elevation and relief. On-going
reclamation will limit the number of acres disturbed at any given
time to about 700-800 acres.
Proposed mining will disturb the existing soils on approximately
75% of the site. Existing soil profiles will be destroyed and
in general the surface horizon will be buried. Waste disposal
and physical reclamation will result in three new types of
surface soils: clay, sand-clay, and overburden. Each of the
new reclaimed soil types has distinct agricultural and
engineering properties that relate to post-reelamation land use
potent i al.
The average annual ground-water withdrawals will be limited to
13 mgd less recharge of 3 mgd for a total net consumption use
of 10 mgd. During the fourth year of mining, approximately 2.88
mgd of water will be diverted from the East Fork of the Manatee
River to a surface water storage reservoir.
The primary effect of withdrawals from the deep ground-water
system is the lowering of the potentiometric surface within the
area of influence of the wells. This effect will be extremely
small in comparison to the large seasonal fluctuation. Potential
impacts to water quality in the deep aquifer system may be caused
by the dewatering/recharge projects which directly transmit water
from the shallow system to the deep aquifer system. Monitoring
of the quality of water being discharged is required by the
Southwest Florida Water Management District.
The primary effect of the mining on the shallow ground-water
system will be the lowering of the water level within the system
by the dewatering and/or recharge wells.
The proposed reclamation project may cause changes in water
quality in the surficial aquifer as well as changes in on-site
flow patterns within the surficial aquifer.
During active mining, stream flow into Lake Manatee will decrease
by approximately 9%. After reclamation the average flows of
the East and North Forks of the Manatee River will be reduced
approximately 0.7 mgd and 0.6 mgd respectively. This decrease
will be the result of increased impoundments in lakes and marshes
and the sand/clay mix land fills. The major drainage courses
on the mine site will be left undisturbed, except for a small
segment of the East Fork Manatee River.
Discharges to streams leaving the proposed mine site from the
plant water system may be necessary due to temporal variation
in rainfall. It is anticipated that approximately 1.9 mgd will
be discharged into the East Fork of the Manatee River during
August and September of an average rainfall year; effluent will
be discharged at a rate of 1.8 mgd into the North Fork during
August, September, and October.
The proposed mining may be expected to contribute both primary
and secondary air quality effects. Primary effects will be
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contributed by the operation of two phosphate rock dryers,
storage, materials handling, and shipping facilities, as well
as fugitive dust from land clearing and reclamation activities.
Secondary effects will be contributed by population, corrmerci al ,
and industrial development induced by the proposed project.
Primary emissions from the rock dryers and associated facilities
are very fine clay and phosphate rock particulates and
by-products of the combustion of fuel oil, e.g., sulfur dioxide
and ash. The proposed sources will not violate air quality
standards nor significantly degrade air quality. SO7 and
particulate matter emissions will satisfy New Source Performance
Standards and BACT.
There are no significant noises associated with mine-related
activities that could be considered intrusive or detrimental
to sensitive receptors because of spectral content or
i ntermi ttency.
A potential direct impact of mining and beneficiation is that
of occupational radiation exposure. The primary exposure areas
are the rock pile transfer tunnels. The Duette operation, having
both a plant design including properly ventilated tunnels and
a lower product radioactivity level than the general mining
region, should not exhibit adverse occupational exposure. The
proposed fugitive dust control on dryer emissions should also
limit off-site transport of airborne radioactivity to the point
where annual dose cannot be measured within the statistical
variation of natural background.
Upon completion of mining, reclaimed lands will have different
radiological characteristics than the land before mining.
Considering future agricultural uses of the site, the most
important pathway is the direct uptake of radium-226 by row crops
grown on the reclaimed clay settling area. Although the radium
content is highest here, the land will be agriculturally suited
for row crops. Study results suggest that the excess
availability of the major cations produce a discrimination
against uptake of Ra++ in the clay soils containing higher than
normal radium-226. Regarding future residential development
of the site, predicted indoor radon progeny levels indicate only
the reclaimed settling area may produce levels requiring remedial
action. The predicted clay land form indoor radon progeny level
is 0.023 WL (working level). If the clay settling areas are
excluded for structural reasons or topsoil replacement occurs,
no reclaimed lands are predicted to produce homes with radon
progeny levels near the 0.02 WL remedial action level.
Surface water radium-226 concentrations in off-site environs may
be elevated from natural levels of 0.8 pCi/1 to 2 pCi/1. The
drinking water standard for radium-226 is 5 pCi/1. The ground
water radium-226 concentrations at the site are between 0.8
and 6 pCi/1 and are less than those observed in non-mining*
regions. Radium-226 levels in ground water appears to be
associated with local subsurface conditions which are below the
zone of surface mining influence.
The socioeconomic impact of proposed mining will exhibit a
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generally beneficial effect. Operation of the mine will directly
require 324 workers, many of which will be relocated employees
of the applicant. Some workers will be obtained from the Manatee
County labor force. The direct economic effects of the mine
are favorable, producing approximate annual yields of $382,400
in sales tax, $1.92 million in severance tax and $1.982 mi 11ion
in Ad Valorem tax. Regional economy effects derived through
standard multipliers indicate an annual indirect impact of $35.4
million and an annual induced impact of $118.4 mi 11ion.
Estimated employment associated with the activity is similarly
projected to be 235 through indirect impact and 1425 through
induced impact. The mine will exert no directly discernable
effects on community services and facilities as the operation
will be self-sufficient in terms of minor medical treatment,
water supply, fire and police protection, solid waste disposal
and internal transportation facilities. The mine will not
measureably increase demand on regional facilities for education,
major medical treatment, recreation and transportation.
Long-term land use patterns will not be adversely impacted by
the mining activity. The site is proposed for agricultural uses
in the Manatee County Comprehensive Plan. The planned mine
reclamation program is designed to return the site to land forms
amenable to a variety of agricultural uses. On the short-term,
the proposed mine site is located between two approved phosphate
mines and therefore should not disrupt near-future land use
trends in the area.
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TABLE OF CONTENTS
Page
1. 0 INTRODUCTION 1
1.1 Identification of the Applicant 1
1. 2 Obj ec t i ves i
1.3 Project History 2
2. 0 ALTERNATI VES EVALUATION 3
2.1 Plant Site Alternatives 3
2.2 Production Rate Alternatives 5
2.3 Resource Recovery Alternatives 6
2.4 Mining MethodAlternati ves 8
2.5 Ore Transportation Alternatives 9
2.6 Beneficiation Process Alternatives 10
2.7 Process Water Source Alternatives 11
2.8 Waste Disposal/Reelamation Alternatives 12
2.9 Surface Water Discharge Volume Alternatives .. 15
2.10 Discharge Point Alternatives 16
2.11 Rock Drying Alternatives 17
2.12 Product Transportation Alternatives 21
2.13 Energy Source Alternatives 21
2.14 No-Action Alternative 22
3.0 DESCRIPTION OF PROPOSED ACTIVITY 24
3.1 Mi ni ng Operat ion 24
3.2 Process Description 26
3.3 Product Disposition 26
3.4 Waste Disposal 26
3.5 Water Management System 27
3.6 Reclamation Methodology 28
4.0 DESCRIPTION OF BASELINE, IMPACTS, AND MITIGATING
MEASURES OF THE NATURAL ENVIRONMENT 31
4.1 Meteorological Conditions 31
4.2 AirQuality 32
Baseli ne
Impacts
Mitigating Measures
33
4.3 Noise
Basel i ne
Impact s~ ............................... 46
Mitigating Measures ....................... .*.'." 49
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TABLE OF CONTENTS
(Cont i nued )
Page
4.4 Topography
Basel i ne
Impacts ...................................... 49
Mitigating Measures .......................... 51
4.5 Soils ........................................ 51
Basel ine ..................................... 51
Impacts ...................................... 52
Mitigating Measures .......................... 54
4. 6 Geology ...................................... 55
Basel i ne ..................................... 55
Impact s ...................................... 56
Mitigating Measures .......................... 56
4.7 Groundwater Hydrology ........................ 56
Basel ine ..................................... 56
Impact s ...................................... 60
Mitigating Measures .......................... 64
4.8 Groundwater Quality .......................... 67
Basel i ne ......................... . ........... 67
Impacts ...................................... 71
Mitigating Measures .......................... 74
4.9 Surface Water Hydrology ...................... 75
Basel i ne ..................................... 75
Impacts ...................................... 79
Mitigating Measures .......................... 81
4.10 Surface Water Quality ........................ 81
Basel i ne ..................................... 81
Impact s ...................................... 89
Mitigating Measures .......................... 102
4.11 Radiological Environment ..................... 103
Basel i ne ..................................... 103
Impact s ...................................... [i [
Mitigating Measures .......................... 118
4.12 Biology and Ecology .......................... 120
Baseline
120
Impacts 127
Mitigating Measures 133
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TABLE OF CONTENTS
(Conti nued)
Page
Rare & Endangered Species ................... 136
Environmentally Sensitive Areas ............. 138
5.0 DESCRIPTION OF BASELINE, IMPACTS, AND MITIGATING
MEASURES OF THE MANMADE ENVIRONMENT
5.1 Demography
Basel ine .................................... 143
Impacts ..................................... 144
Mitigating Measures ......................... 145
5. 2 Economics ................................... 145
Basel ine .................................... 145
Impacts ..................................... 148
Mitigating Measures ......................... 151
5.3 Land Use .................................... 151
Basel i ne .................................... 151
Impacts ..................................... 153
Mitigating Measures ......................... 153
5.4 Community Service & Facilities .............. 154
Basel i ne .................................... 154
Impacts ..................................... 154
Mitigating Measures ......................... 155
5.5 Sensitive Manmade Areas ..................... 155
Basel i ne .................................... 155
Impacts ..................................... 156
Mitigating Measures .................. . ...... 157
5.6 Transportation .............................. 157
Basel i ne .................................... 157
Impacts ..................................... 161
Mitigating Measures ......................... 162
5.7 Archaeological and Historical Properties .... 163
Basel i ne .................................... 163
Impact s ..................................... 164
Mitigating Measures ......................... 166
5.8 Re source Use ................................ 166
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TABLE OF CONTENTS
(Conti nued)
Page
6.0 COMPARISON OF PROPOSED ACTIVITY WITH AREAWIDE
EIS RECOMMENDATIONS 169
7.0 PROPOSED AGENCY ACTIONS !8Q
Draft Permit 181
COORDINATION LIST i
LI ST OF PREPARERS i i i
SELECTED BIBLIOGRAPHY v
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LIST OF TABLES
Page
2.1-A Economic Comparison of Site Alterna-
2. 2-A
2. 3-A
2.4-A
2.5-A
2.7-A
2.8-A
2.9-A
2.10-A
4. 2-A
4.2-B
4.2-C
4.7-A
4.8-A
4.8-B
4.9-A
4. 10-A
4. 10-B
4. 10-C
Production Rate Alternatives
Resource Recovery Alternatives and
Regulatory Constraints
Comparison of Mining Alternatives
Comparison of Ore Transportation Alter-
nat i ves
Comparison of Alternatives for Water
Cost Comparison Between Alternative
Comparison of Discharge Volume Alterna-
tives
Comparison of Discharge Point Alterna-
Project Emissions (pounds per day)
Log TSP Concentration - Frequency Esti-
mates 1977-78
Log SO? Concentration - Frequency Esti-
mates T977-78
Aquifer Characteristics of the Producing
(Confining) Zones
Ground-water Analysis Results - Installed
We 1 1 s
Ground-water Analysis Results - Existing
We 1 1 s
NPDES Permit Application Effluent
Limi tat i ons
East Fork Manatee River, Mass Loadings
and Concentrations after Mixing
6
7
8
9
12
14
16
17
34
35
38
60
68
69
76
83
91
94
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LIST OF FIGURES
Page
1.1-1 Location ....................................... 1
2.1-1 Alternative Plant Site Locations ............... 3
2.11-1 C & F Port of Entry Cost Differential
Dry vs Wet Rock ................................ lg
2.11-2 Energy Consumpt ion ............................. 19
3.0-1 Mining Operat i on ............................... 24
3.1-1 Master Development Plan with
Dragline Sequence .............................. 25
3.5-1 Process Water Balance .......................... 28
4.2-1 Annual 1977 Total Suspended Particulate
Baseline ....................................... 36
4.2-2 Short-Term (24 Hour) 1977 TSP Baseline at
Locations of Maximum Proposed Source Influence . 37
4.2-3 Long-Term (Annual) Effects of Increment
Consuming Source Particulate Emissions ......... 40
4.2-4 Projected Long-Term (Annual) Effects of All
Stationary Source Particulate Emissions ........ 41
4.2-5 Short-Term (24 Hour) Effects of Proposed
Source Particulate Emissions ................... 43
4.2-6 Projected Short-Term (24 Hour) Effects of All
Stationary Source Particulate Emissions ........ 44
4.3-1 Estimated Day-Night Sound Average Sound Level
(Ldn) Contours at Duette Mine During Operation . 48
4.4-1 Existing Topography ............................ 50
4.7-1 Subsurface Geology and Ground-Water Systems .... 59
4.7-2 Long-term Water Levels of Individual
Producing Zones ................................ 61
4.7-3(a) Generalized Change in the Potent i omet r i c Surface
&(b) as a Result of a 10 rngd Net Withdrawal ......... 65
4.8-1 Well Locations ................................. 70
4.9-1 Average Monthly Fl ows .......................... 78
4.9-2 Peak Flood Discharge ........................... 79
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1.0 INTRODUCTION
1.1 IDENTIFICATION OF THE APPLICANT
Effective August 1, 1979, Swift Agricultural Chemicals
Corporation changed its name to Estech General Chemicals
Corporation. The preparation of the Draft Environmental Impact
Statement was substantially completed at the time of the name
change. Therefore, the name of Swift Agricultural Chemicals
Corporation (Swift) is used throughout this Surrmary Document and
all attendant Resource Documents.
Swift is a wholly owned subsidiary of Estech Incorporated and
has been a leading producer of agricultural chemicals since
1908. Swift presently operates the Watson and Silver City Mines
in Southwestern Polk County, Florida. The Duette Mine phosphate
reserve will serve as a replacement for these facilities as their
production expires.
1.2 OBJECTIVES
Swift proposed a phosphate mining and beneficiation facility,
at the Duette Mine in Northeastern Manatee County, Florida
(Figure 1.1-1). The operation encompasses 10,394 acres, of which
6,600 acres are deemed minable. The operation is planned to
produce three million tons of ore annually for 21 years.
Construction of the facility is scheduled for 1980 with mining
beginning two years later.
Figure 1.1-1 Location of Duette Mine
The water management plan divides the needed supply between
surface and ground-water resources, minimizes process
consumption, and provides for recharge of the Floridan Aquifer.
Discharges of water will be minimized and monitored for
compliance with regulatory requirements. Monitoring will also
include air quality, earthen dam surveillance, and ground-water
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The reclamation plan is primarily intended to return the site
to agricultural uses. The plan proposes preservation of certain
important wetland and upland plant communities and reclamation
to wetlands. Wetland preservation and reclamation areas were
incorporated to provide long-range water quality and biologic
diversity as well as land form diversity, wildlife protection,
recreational uses and water resources.
1.3 PROJECT HISTORY
Swift conducted prospecting in 1964 and 1965 to identify areas
of recoverable phosphate rock. As a result, the 10,394 acre
tract was purchased in 1965 - 1966. During 1975 and 1977, a
study program of surface water and ground-water quantity and
quality was conducted. Concurrently, baseline studies necessary
for the preparation of an Application for Development Approval
(ADA) were initiated. The ADA is part of the overall DRI process
in Florida and is required by any project defined as a
Development of Regional Impact (DRI) in Sec. 380.06, Ch. 22F-2,
FAC.
Dragline purchase commitments were made in 1975 followed by
additional prospecting in 1975 and 1977 to confirm mining areas
for planning purposes and to establish extractable tonnage.
In April 1978, the ADA was filed with Tampa Bay Regional Planning
Council (the State designated Regional planning agency) and
Manatee County Planning and Development Department (the
designated local agency having jurisdiction) to secure proper
zoning. In addition, a Master Mining Plan, as required by
Section III Manatee County Mining Ordinance, was submitted to the
1ocal agency.
In May 1978, the Duette Mine was designated by EPA a new source
as defined in Sec. 306 of the Federal Water Pollution Control
Act Amendments of 1972. Pursuant to this determination, the
procedures specified in the National Environmental Policy Act
were initiated which includes the preparation of an environmental
impact statement as an integral part of th National Pollutant
Discharge Elimination System (NPDES) permit application.
In September 1978, a Consumptive Use Permit (CUP) was issued by
the Southwest Florida Water Management District (SWFWMD) pursuant
to the requirements of Ch. 373, FS. and Ch. 16J-2, FAC. This
state permit explicitly regulates the consumptive use of surface
and ground water.
Other Local, State, and Federal permit applications are in
various phases of development and are expected to be completed
by October 1979.
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2.0 ALTERNATIVES EVALUATION
The alternative assessments include: plant site location,
production rate, resource recovery, processes for mining and
beneficiation, water supply, waste disposal and reclamation
techniques, discharge into surface water, rock drying, product
transportation to port, power sources, and no-action. Objectives
to be met in selection of the optimum alternatives are
i dent i f i ed.
2.1 PLANT SITE ALTERNATIVES
It is the objective of a beneficiation site to be placed at a
location that minimizes: 1) loss of phosphate resource; 2) water
pumping cost; 3) ore and waste transportation cost; 4) road and
utility construction cost; and 5) destruction of environmentally
sensitive areas. Alternative sites are shown on Figure 2.1-1.
Figure 2.1-1 Alternative Plant Site Locations
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Resource losses associated with alternative sites are: Site
1 - 511,500 tons; Site 2-0 tons; Site 3 - 2.325 million tons;
Site it - 1.6 million tons; Site 5 - 1.6 million tons; Site 6
- 0 tons. The lowest net energy costs result from locating the
plant site at the center of the ore body (Site 4) as shown in
Table 2.1-A. The cost of material transportation is the most
significant cost consideration. Energy consumption represents
about 60% of this cost. In comparison, water pumping costs are
small. Offsetting the savings in sites 4 and 5 is the resource
loss. Locating the plant site nearer to existing access roads
reduces development costs, but results in higher material
transportation costs. Site 6 is considered as nil cost effect.
Table 2.1-A Economic Comparison of Site Alternatives
Site 1 Site 2 Site 3 Site 4 Site 5 SiteT
Reserve Loss
(Short Ton
Product $000's) 511.5 0 2,325 1,600 1,600 0
Cost Water Pump
($/ton Product) +.006 +.007 0 +.0015 -.006 0
A. Energy Cost +.005 +.006 0 +.0012 -.005 0
Matr ix and Waste
Pumpage ($/ton
Product) +.50 -.14 +1.99 -.47 -.19 0
A. Energy Cost +.45 -.12 +1.80 -.39 -.17 0
Total Energy
Cost ($/ton
Product) +.461 -.107 +1.80 -.383 -.181
Access Road,
Railroad, Utility
Cost ($000's) +250 -80 +900 0 -22 0
Sites 4 and 5 have essentially the same environmental
ramifications as the proposed location (site 6). Site 3 exhibits
the greatest potential for disturbance of wooded floodplains
preserved as a wildlife corridor and for damaging aquatic habitat
due to minor spills and surface water withdrawal. This site
also necessitates destruction of the environmentally sensitive,
18 acre cypress dome. It may also result in unacceptable noise
levels at sensitive receptor sites. Site 2 exhibits some
potential for wooded floodplain disturbance but does not
otherwise differ significantly from the Swift proposal. The
primary constraint on Site 1 is the potential for unacceptable
air pollutant levels at the property boundary.
From the energy and cost point of view, the two most feasible
alternatives are the Swift proposal (site 6), which would
minimize ore transportation costs, and the western boundary
location (site 2), which would have smaller material
-------
transportation and development costs than site 6. Site 2 does,
however, exhibit a somewhat greater potential for damage to
environmentally sensitive areas (f1oodplains) than site 6.
2.2 PRODUCTION RATE ALTERNATIVES
It is the objective of a production rate to produce rock that
will make the corresponding cost of production competitive in
the world market; to insure a reasonable profit; to maintain
a production rate that will respond to overall rock demand
growth; to replace present production as existing Swift
facilities mine out; and to meet environmental permitting
requi rernent s .
The alternatives selected to illustrate various production rate
effects rather than to definitely designate the optimum are
production rates of 1.5 million tons per year, 3.0 million tons
per year and 4.5 million tons per year.
Table 2.2-A surrmarizes the typical dragline requirements, capital
costs, and production costs for the three production rate
al ternat i ves.
To meet Swift's overall objective, mining at a rate that will
make the production costs competitive and will maintain their
share of the market, it appears their proposed production rate
has been reasonably selected.
Alternative one, at 1.5 million TPY, shows no growth increase
and is a 10.7% reduction from present production. Alternative
two, at 3.0 million TPY, replaces mined out production and
provides for demand growth of the phosphate industry.
Alternative three, at 4.5 million TPY, is excessive in that it
is decidedly more than necessary to replace existing capacity
and is in excess of historical growth rates.
Consideration of environmental aspects indicate all alternatives
would have essentially the same long-term effects on vegetation
and wildlife. Positive aspects of alternative one is that lower
ground-water withdrawal rates would cause the least stress on
regional water resources and annual particulate emissions would
be lowest. Annual SO2emissions would be largely the same for
alternative one and two but the long-term contributions of one
would be twice that of alternative two. Alternative three has
a considerable potential to exceed ground-water withdrawal
limitations and exhibits the highest air pollutant
cont r i but i ons.
-------
Table 2.2-A Production Rate Alternatives
^Capital Cost^Production
Mine and Mill Cost Mine and
M $ Mill M $
Production Draglines
TPY No. Yards M $
1,500,000
3,000,000
4, 500,000
1
2
3
50
50
50
13.0
26.0
39.0
53.55
90.00
119.54
20.875
18.284
18.000
*"Evaluation of the Phosphate Deposits of Florida Using the
Minerals Availability System." Bureau of Mines. Open File
Report No. 112-78. Zel1ars-Wi 11iams , Inc. June, 1978.
2.3 RESOURCE RECOVERY ALTERNATIVES
It is the objective to maximize recovery of the non-renewable
mineral resources at an acceptable cost with consideration given
to impact on renewable natural resources, principally wetlands.
Three cases of resource recovery are considered. Case 1, the
proposed action, represents the mining and reclamation plan of
Swift. Resource recovery of this plan would be about 61.5
million product tons of phosphate rock recovered over a 20-21
year mining period. In achievement of the proposed recovery,
Swift has excluded the lower quality "unmineable" ore and ore
of varying quality underlying much of the forested swamp
corrmunity found along major water courses and the cypress dome.
Case 1 includes mining approximately 360 of the 600 acres of
freshwater marsh, 55 acres of the East Fork Manatee River, and
most of the small feeder streams.
Case 2 excludes the mining of all freshwater swamp but includes
mining of marshes as in Case 1. Resource recovery would be about
57.65 million product tons of phosphate recovered over a 19-20
year mining period. A presumption in this case is that, with
the exception of a higher depreciation rate to account for the
resource loss, higher extraction costs would not result.
Case 3 includes recovery of all phosphate rock resources
regardless of vegetative cover or current land use. Resource
recovery would be about 65.9 million product tons of phosphate
recovered over a 21 1/2 - 22 1/2 year mining period. The case
includes mining of approximately 950 acres of forested swamps
(including most of swamp along major drainage courses and the
cypress dome) and mining of marshes as in the previous cases.
Table 2.3-A shows
recovery cost and
the tradeoff relationship between resource
regulatory constraints.
-------
Table 2.3-A
Resource Recovery Alternatives and
Regulatory Constraints
Changein Resource
Recovery
Change in Cost
Meets Regulatory
Const raints
Case 1 - Proposed
Ac t i on
Case 2 - Loss of
of 3,850,000 tons
Case 3 - Add
4,400,000 tons
rock
-0-
Would create slightly
higher depreciation
rate to account for
the resource loss.
Any mitigative action
would add to costs.
Permit required for
East Fork Manatee
River System
Would meet maximum
const raints
regarding wetland
protect i on
Would require
approval of DER
and Corps of
Engineers
Case 1, as proposed by Swift, is presented as nil cost. Case
2 has a nil cost effect but would lead to loss of 3.85 million
tons of phosphate resources. Case 3 increases resource recovery,
but has the unknown but assumably significant cost effect of
adding extensive mitigative action (wetlands restoration).
With regard to the tradeoff relationship between resource
recovery and potential adverse impacts on marsh-type systems,
it appears negative effects would, at worst, be of low magnitude
and significance considering both biologic and hydrologic
functions. For all cases, freshwater marsh re-establishment
through reclamation is expected to be a relatively rapid process
even when un-assisted. Although the potential exists for
development of pure stands of cattails in constructed depressions
and lake littoral zones, this occurance would not be expected
to significantly affect the hydrologic function of the re-
established marshes. The cattail marshes would also be expected
to support many of the animals inhabiting pre-mining marshes
of the site.
Concerning the balance between resource recovery tradeoffs and
potential impacts related to mining of freshwater swamps, each
alternative offers distinctly different implications. Case 2
represents the "least risk" alternative as all wooded wetlands,
regardless of importance, would be maintained intact. This would
incur the irretrievable loss of several million tons of phosphate
rock product over the other alternatives. Case 3, on the other
extreme, offers maximum resource recovery but with the potential
of incurring highly significant, high magnitude adverse effects
on all important biologic and hydrologic systems if freshwater
swamp regrowth is unsuccessful. Case 1, not necessarily
intermediate to the extremes, also offers the possibility of
moderately significant, high magnitude adverse effects if
freshwater swamp regrowth is unsuccessful in the mined, one-mile
segment of the East Fork Manatee River.
Based on the operation cost/resource recovery and potential
-------
impact/resource recovery comparisons made, the current optimal
alternative would appear to be somewhere between Case 1 -Proposed
Action and Case 2 - Swamp Exclusion as large scale wooded wetland
restoration efforts are unproven. Case 2 includes preservation
of some wooded wetlands that are isolated and/or normally
intermittent in nature and exhibit insignificant or minor
hydrologic and biologic functions. Conversely, Case 1 proposes
mining of largely undisturbed, heavily wooded floodplains that
contribute significantly to the overall hydrologic and biologic
functioning of site and general area.
2.4 MINING METHOD ALTERNATIVES
Mining method objectives are maximum recovery of the mineral
resource at optimum cost with reasonable use of energy, water,
and environmental resources. Mining is to be conducted to allow
for efficient and useful land reclamation.
Only open pit (strip mining) ore extraction methods are
considered feasible since underground mining is not suited for
sandy soils prevalent in Manatee County. Mining method
alternatives, therefore, include large electric walking draglines
(proposed case), dredges, bucket wheel excavators (BWE) and
technique combinations.
Table 2.4-A surrmarizes the factors evaluated in the mining
methodology assessments.
Table 2.4-A Comparison of Mining Alternatives
I tern/Case
Ore Recovery
Cost, $/Ton, Prod.
Energy Use, KWH/Ton
Water
Env i r onmenta 1
Safety
Dragl i ne
85-87%
1.30
12.6
B
E
S
Dredges
80-82%
1.38
25.0
S
E
S
Wheels
88%+
1.99
21.7
B
E
P
Combi nat i on
88%+
1.38
22.9
S
E
P
Ratings: B-Best, S-Satisfactory, P-Poor, E-Equal
With regard to ratings shown in the table, the conventional
dragline mining operation does not consume water directly.
Dredge mining may result in a minor loss of water by formation
of colloidal clays when dredging and pumping overburden. From
a water conservation standpoint, draglines and bucket wheels
are preferred. Open pits (draglines and BWE's) temporarily
affect the adjacent water table by pit dewatering. Dredges would
have less impact if pools are maintained at a high level.
With regard to safety, "in the pit" operations can be hazardous
due to highwall failures. Thus, the bucket wheel technique is
considered to be less safe than other methods. Dredge operation
requires people to work over water, which can be hazardous.
Failure of highwalls is also possible in dragline operations.
-------
All open pit extraction alternatives would exhibit largely the
same long-term impacts on vegetation and wildlife assuming like
areas are mined and are similarly reclaimed. The dredge method
would not, however, necessitate dewatering of the mine pit and
the attendant lowering of the water table on either side of an
act i ve pit.
Based on the tabular comparison, the dragline would be preferred
although dredging would be acceptable.
2.5 ORE TRANSPORTATION ALTERNATIVES
Transporting the matrix from the mine to the beneficiat ion plant
should be achieved at a minimum cost with optimum use of
resources and with minimal effect on the environment. The
alternatives which merit consideration include conventional
slurry pumping (proposed action), conveyors, and trucks.
The factors considered in the assessment of ore transportation
alternatives include technical and operational feasibility, cost,
energy use, water use/conservation, and environment. Table 2.5-A
compares the factors considered in the ore transportation
a 1ternat i ves.
Table 2.5-A Comparison of Ore Transportation Alternatives
I tern/Case
Cost $/ton,
Energy Use,
Water
Envi ronment
Operati onal
Product
KWH/Ton
Pumpi ng
$ 0.92
17. 3
E
S
S
Conveying
$ 0.88
11.2
E
B
U/P
Tr ucki ng
$ 1.33
N/A
E
P
P
Rates: B-Best. S-Satisfactory, P-Poor
U/P-Unproven
is i ncluded
in phosphate. Energy
in the Cost $/ton.
E-Equal
use (KWH)
for trucking
The slurry method is currently used
the Central Florida field and has
operational feasibility.
by companies operating in
proven technical and
In the conveyor method, uniform feeding of matrix to the belt
would be a significant problem. Draglines could not place 50
tons of matrix directly in a belt feed hopper. It would be
necessary to provide an intermediate receiving and belt feeding
system. I(t is also necessary to disaggregate the belt-conveyed
matrix with high pressure water and harrmer mills once it arrives
at the washer.
Truck transportation of ore is practical in many mining
operations and very large trucks have been developed for this
purpose. Operational problems associated with truck transport,
however, would include secondary handling of the matrix (small
bucket wheel or payloader) as they cannot be loaded directly
with a 50 cubic yard dragline, disaggregation of ore at the
-------
washer and labor intensity of truck driving and maintenance.
Road construction would also cause problems for trucks (e.g.
river crossings, highway crossings, poor soil conditions, heavy
seasonal rainfall).
The use of water as a medium of transport in pumping does not
consume water. The alternative ore transportation systems are
similar in effect on water use since, in each case, the ore is
d i sagg regated.
Concerning the environmental ratings, pumping and conveying
alternatives would each eliminate about 15-20 acres of wetland
vegetation due to construction of stream crossings. It is
assumed the construction of truck crossings would eliminate some
greater amount due to the need for heavy duty bridges on pilings
or culverts with approach fill.
The pumping and conveyor alternatives each offer a potential
for spillage of transported materials at stream crossings.
Extensive spills of truck transported materials into streams
is considered remote. The greatest potential for adverse effects
related downstream sedimentation by spill materials would appear
to be associated with pipe-wall rupture in the pumping
alternative if secondary protective measures fail.
The only alternative with significant implications for addition
to air pollutant burdens is the truck transportation
alternat i ve.
Due to lower energy costs, transport of ore by conveyor is the
most economical alternative; however, the operational viability
of this method is unproven. The problem associated with
transferring the ore from the dragline to the conveyor and the
need to relocate the conveyor continuously as mining advances
are significant disadvantages of the conveyor transport method.
The continuing increase in power cost makes further study of
this alternative prudent. However, in view of the proven
reliability of pumping and its compatabi1ity with the dragline
and dredge mining alternatives, the ore pumping alternative is
currently the most satisfactory ore transport method.
2.6 BENEFICIATION PROCESS ALTERNATIVES
The purpose of beneficiation is to reject the maximum amount
of contaminants while recovering the maximum amount of phosphate
from the ore. These objectives are to be achieved at optimum
cost considering the end use of the rock product. The processes
employed are to be energy and water use efficient.
The alternatives to conventional beneficiation do not offer any
effective solutions. The total acidulation process (direct acid
conversion of matrix) is only experimental and not available
for use at this time. Furnace alternatives (high temperature
decomposition) are cost and energy intensive and unsatisfactory
lor this ore body. Thus, conventional beneficiation is
considered optimum.
10
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2.7 PROCESS WATER SOURCE ALTERNATIVES
The process water supply objective is to provide water to the
mining operation of sufficient quality and quantity to optimize
operational and mineral recovery efficiency while conserving
the regional water resource.
Supply alternatives considered are: use of surface and ground
water (proposed action), total requirement from the deep Floridan
Aquifer, use of surface water in rainfall catchment and use of
water from the surficiai (water table) aquifer.
Table 2.7-A compares the quality, dependability, energy cost,
and resource impact of the water supply alternatives. The
ground-water resource, whether from the shallow or deep aquifer,
is presumed to be of highest quality. The availability of water
from the deep aquifer is assumed the most dependable.
Swift's base case (Alternative 1) uses both ground-water and
surface water. This alternative provides for a dependable source
of sufficient high quality water for the beneficiation process
and reduces the impact on the deep aquifer compared to the
exclusive use of ground-water (Alternative 2). Pumping costs
are also less for this alternative relative to ground-water
pumping alone.
Alternative 2 (Floridan Aquifer) impacts only the ground-water
resource in the deep aquifer. This alternative provides for
a dependable source of high quality water. Pumping costs are
slightly higher than for Alternative 1. The impacts of
ground-water pumping are acceptable for the first three years,
but for the long term, Alternative 1 is preferred because of
its reduced impact on the deep aquifer.
Alternative 3 (rainfall catchment) has the lowest pumping costs
but is not acceptable in terms of water quality or
dependability. In addition, this alternative has the potential
of reducing the downstream surface water supply, would destroy
hardwood floodplains by reservoir construction, and has not been
proven technically feasible.
Alternative 4 (surficiai aquifer) has the highest pumping costs
and would not provide a dependable source of water. In addition,
this alternative would have an adverse impact on the maintained
vegetation on site because of drought conditions imposed on the
surface soils for the 20-year mining period.
In view of these considerations, the base case as proposed by
Swift (Alternative 1) is the optimum blend of various resource
uses and power cost considerations. The mitigative action of
implementing recharge wells makes this alternative even more
at t ract i ve.
11
-------
Table 2.7-A Comparison of Alternatives for Water Supply
Alt,
Al t .
Alt.
Quality*
//I
#2
Exce
Poor
Exce
llent G/W
S/W
llent
Dependabi 1 i ty
Dependabl e
Dependabi e
Resource
Impact
G/W
G/W
and S/W
only
Pumpi
Cos
$72,
$80,
ng
t
000
000
Alt. //3 Poor Not dependable S/W vegetative $47,000
sys tem
-------
reclamation of the approximately 255 acres required for the plant
site and support facilities would be the same for both cases.
All reclaimed areas initially would be planted in forage
species. As is frequently practiced, scattered tree plantings
would be made in reclaimed pasture areas at a density of two
trees per acre, of which half would be 2"-4" transplants and
half would be potted seedlings. Since wetland restoration is
not currently part of conventional reclamation technology, it
was assumed that no areas would be restored as wetlands. Also,
no areas would be allowed with minimal reclamation to revegetate
naturally since this is at variance with current local and state
reclamation standards.
Case 11 - Case II is the Swift plan. Under this plan, the
sand/clay mix technique is the primary waste disposal method,
requiring a total of 5,426 acres, of which all but 200 acres
are in mined-out areas. An initial 480-acre conventional clay
settling area with a dam height of 30 feet is required on unmined
land. Approximately 848 acres of conventional sand tailings
disposal areas in mined-out pits are also elected. The remaining
574 acres of mined-out land is not utilized for waste disposal.
All sand/clay landfills are reclaimed without the use of capping
material. The single clay settling area is reclaimed by the
crust development technique and sand tailings disposal areas
are capped with approximately two feet of overburden. The
acreage not required for waste disposal is reclaimed as land
and lake areas. Of this 574 acres, shallow zones amenable to
marsh establishment would be created on approximately 90 acres
along the margins of four reclaimed lakes and a 100-acre area
would be physically altered only by the partial leveling of
spoils to provide an area amendable to natural revegetation.
The 255 acres required by the plant site and support facilities
will be physically reclaimed by conventional means of dismantling
facilities, grading to approved slopes, etc.
Revegetation plans for Case II include the planting of 5,928
acres of improved pasture with a mixture of grass and legume
species. Mixed forest strips totalling approximately 58 acres
would be planted in upland reclaimed pasture areas.
Approximately 485 acres of forested wetlands would be planted,
primarily along major drainage swales and also along a restored
segment of the East Fork Manatee River. Approximately 538 acres
of shallow aquatic environments created in sand/clay landfills
would be allowed to revegetate naturally. Along with the 90
acres of shallow zones created in the margins of reclaimed lakes,
this constitutes a total planned marsh restoration of 628 acres.
The 100-acre land and lake area subjected to only partial spoil
grading would be allowed to revegetate naturally. All the land
areas associated with the remaining 384 acres of land and lake
areas would be grassed.
The two cases must be judged on the basis of their relative costs
and on their ability to achieve the applicant's economic and
environmental objectives for the reclaimed site. Ideally, the
lowest cost method will produce the most favorable results.
13
-------
In lieu of such ideal conditions, the economic and environmental
productivity of the reclaimed site should justify the added cost
i ncur red.
Developing precise figures for waste disposal/reelamation costs
requires input data derived from detailed engineering studies.
This is, of course, not possible when comparing two conceptual
alternatives. A further complicating factor in this analysis
is that there is very little actual field experience with the
sand/clay mix technique upon which to base cost estimates.
Nevertheless, it is possible to make approximate cost comparisons
based on published methods of estimating mining and reclamation
costs (Zellars-Wil1iams, Inc., 1977b; Zel1ars-Wi11iams, Inc.,
1978). Table 2.8-A summarizes the cost comparison between the
two described cases based on these methods of cost estimation.
Table 2.8-A Cost Comparison Between Alternative Cases
~Cost/TonCost/Ton
Total Product Total Product
-Case I Case II
Waste Disposal/Physical
Restorat ion
o Conventional Clay
Settling Areas $42,365,000 $0.689 $ 3,026,000 $0.049
o Sand Ta i1i ngs
Disposal Areas $21,414,000 $0.348 $ 4,704,000 $0.077
o Sand-Clay Mix
Areas - - $68,504,000 $1.114
o Land and Lake
Areas - $ 760,000 $0.012
o Plant Site and
Support Facilities $ 128,000 $0.002 $ 128,000 $0.002
Revegetation $ 2,797,000 $0.046 $ 2,663,000 $0.043
Grand Total $66,704,000 $1.085 $79,785,000 $1.297
According to this cost comparison, Swift's selected waste
disposal/reelamation plan will cost $0.21 more per ton of product
produced or approximately 20 percent more than conventional waste
disposal/reelamation techniques.
In rating the two cases for achievement of long-term economic
goals, Case II must be given the preference. The approximately
5,400 acres of sand/clay soils planned in this alternative are
projected to be more productive than the soils which result from
conventional waste disposal/reelamation techniques. Moreover,
under Case II, disturbed land will be returned to a productive
use at an earlier date than for the conventional waste disposal
case.
The risk of a dam failure and its resulting environmental (and
economic) damage is greater in Case I. Case II has the most
obvious advantage over Case I in the area of revegetation efforts
to mitigate the loss of natural conrmunities to mining. In Case
14
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I, all reclaimed areas would be improved pasture resulting in
a permanent loss of 364 acres of marsh and 476 acres of swamp.
As river swamps and marshes were found to be the most productive
wildlife habitats of the site, the reduction would significantly
reduce the long-term carrying capacity of the mine site. In
Case II, a variety of revegetation efforts are proposed to
attempt re-establishment of destroyed wetland habitat. The Case
II planned restoration of over 1,100 acres of wetlands represents
a significant contribution towards mitigating adverse impacts
of mining on local wildlife populations. Additionally,
reforestation strips (hedgerows) in upland areas and abandonment
of a minimally reclaimed 100 acre area will provide areas of
wildlife habitat not available in Case I.
The advantages Case II offers, in terms of both the economic
and environmental productivity of the reclaimed site, appear
to justify the added costs this alternative imposes over the
more conventional Case I alternative. Case II, therefore, may
be designated as the optimum alternative. Due to the conceptual
basis of the plan, it is expected that modifications will be
made (in practice) in response to more detailed engineering and
to variables in actual operations.
2.9 SURFACE WATER DISCHARGE VOLUME ALTERNATIVES
The objective is to keep the amount of discharged water to a
practical minimum, dictated by feasible economic limitations,
while maintaining the quality of all discharged water at the
applicable standards for the receiving water. Alternatives
considered regarding discharges from the mining operations
include: 1) Containment of long term accumulation (55 in.
rainfal1/yr.); 2) Containment of short term accumulation (50
in. rainfal1/yr.); 3) Containment to offset evaporation losses
only (Proposed Action) and 4) No containment.
Table 2.9-A summarizes the alternatives. The optimum
alternative, based on the comparison, is number three.
Alternative one is costly and it possesses the potential for
dike failure. Alternative two is also substantial1y more costly
than alternative three and possesses the potential for dike
failure, as in alternative one. A financial or resource loss
would also be incurred due to the construction of impoundments
over areas containing mineable phosphate ore. The reduced
potential for surface water degradation or water conservation
is not deemed sufficient to offset the previously mentioned
negative attributes. The selection of the third alternative,
however, does not completely define it as the optimum possible
system. Improvements or modifications possibly can be
implemented by Swift, during design or operation, to further
feasibly reduce discharge. Alternative four would require
additional water to be obtained from either the rivers or
deepwells.
15
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Table 2.9-A Comparison of Discharge Volume Alternatives
Estimated Initial Potential Effect on Surface
Impoundment Costs Liability Water Quality Remarks
Al t. 1
Alt. 2
.3 mi 11 ion
$2.1 mi 1 1 ion
Al t. 3
None
Maximum
Simi 1 ar
to
Alt. 1
Mi nimum
Al t.
None
Mi nimum
None
Potential for
increase in
TDS and TSS
in receiving
s t ream.
Increased
potential for
increase in
TDS and TSS
in receiving
s t r earn.
Loss of resource:
due to extra
impoundment
cons t ruct i on.
Loss of resources
due to extra
impoundment
cons t ruct i on.
Discharge must
be acceptable
quali ty
Increased Discharge must
potential for be acceptable
poss i ble
increase in
TDS and TSS
in receiving
s t ream.
quali t y.
2.10 DISCHARGE POINT ALTERNATIVES
The objectives of discharge point selection are to maximize water
conservation and management at the lowest cost while meeting
water quality standards for the receiving waters. The
alternatives assessed regarding their ability to achieve the
stated objective include : 1) discharge directly into East and
North Fork Manatee River; 2) discharge directly into North Fork
and into pool connected to East Fork Manatee River; 3) discharge
directly into North Fork, into river overflow pool when not full,
and directly into East Fork when river overflow pool is full
(Proposed Action); 4) discharge directly into East Fork Manatee
River; 5) discharge into river overflow pool connected to the
East Fork; 6) discharge directly into East Fork Manatee River
when overflow pool is full; 7) discharge directly into North
Fork Manatee River; and 8) deepwell injection of all discharge
water.
Assuming they meet water quality standards, all alternatives
appear acceptable with the exception of alternative eight. The
optimum alternatives based on comparisons presented in Table
2.10-A would be alternative two or Swift's plan (alternative
three). Both alternatives maximize water efficiency and minimize
discharge although alternative two is more cost effective. The
cost difference is, however, off-set by operational effectiveness
16
-------
of discharge flexibility inherent in alternative three.
Alternative eight is rejected because of increased risk of
contaminating ground water and the high capital cost associated
with deepwell injection.
Table 2.10-A Comparison of Discharge Point Alternatives
Al ternat i ves
1
2
3
4
5
6
7
8
Estimated
Capital Cost
$ 18,000
12,000
19,000
15,000
9,000
16,000
3,200
600,000
Water Management
Ef f ic i ency
Fai r
Good
Good
Poor
Fai r
Fai r
Poor
Fai r
2.11 ROCK DRYING ALTERNATIVES
The objective is to prepare the phosphate rock for shipment in
a condition acceptable to customers while meeting regulatory
requirements regarding air pollution. The alternatives selected
for assessment are: 1) Install rock dryer at the Duette Mine
(Proposed Action); 2) Ship wet rock; 3) Use existing dryer at
remote location; and 4) Install rock dryer at a remote location.
The proposed action of drying the rock at the mine is the least
costly while meeting the objective of providing an acceptable
product to the customer. The cost of transhipment, primarily
the handling of the rock at a separate dryer site, adds more
than $1.00 per ton to the cost of the product; therefore,
contract drying at an existing site or construction of a new
dryer at an alternate site are expensive alternatives. Drying
at a port facility could be a viable alternative since the
product would of necessity require some handling and possibly
storage which would normally be a part of the mine's dryer
facilities. These costs would then be transferred from mine
to port site. Cost savings in fuel for drying are also a
possibility at a port location. There are no existing public
port facilities, however, that offer these advantages to Swift.
In terms of operating costs at the mine plant site, shipping
wet rock is less expensive than drying the rock. These costs,
however, are only transferred and increased if the customer is
not capable of processing the wet rock since water must be
shipped and then removed by drying. As shown in Figure 2.11-1,
the heavier wet rock results in higher delivered costs at all
17
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points of delivery except the lower Mississippi. Beyond the
1,000 mile radius, shipping costs exceed drying costs; therefore,
the competitive marketing cost becomes a major factor. Product
grade, quality, and condition become more important in the world
market and customer specifications will remain an important
consideration.
?.oo -
1.50
1.00
0.50
-1.00
$4.50/T
500 mi.
S13.00/T
2500 mi.
$13.00/7
5000 mi,
$14.00/T
6000 mi.
$20.00/T
10,000 mi
$13.00/T
5000 mi
LOWER CANADA
MISSISSIPPI
SOUTH EUROPE
AMERICA
FAR
EAST
AVERAGE
DISTANCE
SHIPMENT DESTINATION
Basis: $1.75/Ton to dry rock at the plant site.
Note: Ocean freight rates and mileages are for typical phosphate
shipments from the port Of Tampa.
Figure 2.11-1
C&F Port of Entry Cost Differential
Dry vs Wet Rock.
Total acceptance of wet rock, as the basic form of the phosphate
rock commodity on the world market, is not expected for some
time. Many users have small phosphoric acid plants and the
designs vary widely making conversion to wet rock not only
expensive, but technically difficult. Conversion to wet rock
also requires installation of wet rock grinding in addition to
major wet phosphoric acid process design changes. Significantly,
capital for the modifications is not readily available in many
developing countries.
Some dry rock is used to produce triple superphosphate for which
no wet rock process exists. If drying at the acid plant is
desired, small dryers located at small plants are inefficient
and very expensive compared to the large units employed by rock
18
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producer s.
More energy in the form of fuel oil is consumed to dry the rock
than is consumed to ship the additional water in the wet rock,
assuming that the rock will not be dried at the final
destination. Figure 2.11-2 shows how energy consumption to ship
the moisture in the rock increases with shipping distance and
how it compares with the energy consumption to dry the rock.
In the case of rock dried at the final destination, energy
consumption would be the greatest since the energy consumed
shipping the water would be added to the energy consumed in
drying the rock.
450 -
i n
400
350
300
250
200
150
100
50
IS
J *
o
tx O
LLJ in
g-
o o
<_> o
— o
ENERGY CONSUMPTION TO
SHIP MOISTURE IN ROCK
ENERGY CONSUMPTION
TO DRY ROCK
Figure 2.11-2 Energy Consumption
From an environmental viewpoint, a ranking of alternatives from
best to worst may be characterized and surrrnarized as follows:
o Ship Wet Rock - This is the best environmental choice only
if the rock is not dried in less efficient and less effectively
controlled equipment at the destination. From a standpoint of
phosphate rock customer requirements, it is, in effect, also
a no project alternative. Within the range of available and
viable environmental alternatives, the present preemptive nature
of this alternative suggests that it even be excluded.
19
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With a gradual shift to wet rock grinding and processing
facilities, wet rock shipping may eventually be demonstrated
as reasonably practical and a preferred environmental alternate.
o New Dryer at Remote Site - It is assumed that the site would
be within a developed port facility of the region. Also it is
assumed that the air and water quality conditions at the remote
site are sufficiently marginal with respect to standards that
present source emission regulations could not produce the
necessary conformance to ambient air quality standards and that
the required additional level of emission control would reduce
pollutant contribution to the regional pollutant burden and
produce a better environmental choice. For example, the best
site would be within an area designated for non attainment,
because the new source would have to negotiate at least a
corresponding reduction from another source so that there would
be a projected reduction in area emissions. This extreme example
should indicate potential economic unattractiveness added to
economic disadvantages discussed above.
o Dryer at Duette Mine (Proposed Action) - It is required that
this new facility be designed, constructed and operated in
accordance with the existing body of environmental legislation
and regulations designed to protect the public health and
welfare. It must be recognized that the environmental analyses
suggest these requirements can be satisfied, and in some cases,
with considerable margin. Thus, the alternative is considered
an environmentally acceptable action.
o Use Existing Dryer at Remote Location - Continued or expanded
use of older, less effectively controlled equipment located in
areas marginal with respect to air quality standards would
increase regional pollutant burdens.
Both wet and dry phosphate rock are minor garrma radiation
sources, and there is no measurable difference in radiation
levels between the two products. Lung dosages of radiation are
higher near rock dryers, but conventional dust control systems
maintain radiation levels within the guidelines for occupational
exposures. The application of best available control technology
for new source dryers would reduce pollutant concentration levels
even further. Workers near adequately ventilated wet and dry
rock handling facilities, generally are not exposed to radiation
levels exceeding the guidelines for the general population.
Pollutant Control System Selection: Prevention of Significant
Deterioration (PSD) regulations include a requirement for
application of Best Available Control Technology (BACT) to major
source developments. BACT is a formalized analysis of
potentially applicable control systems and a final selection
based on performance (i.e., pollutant removal efficiency),
economics (i.e., capital and operating costs) and irretrievable
energy requirements. The process is completed following
regulatory approval of the control concept and issuance of a
BACT Determination.
20
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A preliminary evaluation of pollution control systems narrowed
the evaluation to two practical alternatives for both the dryer
facilities and fugitive dust control systems fabric filtration
(baghouses) and wet scrubbing technologies. A review of the
advantages and disadvantages of these systems lead to the
selection of the proposed venturi-absorbers and wet centripetal
vortex contact scrubbers.
2.12 PRODUCT TRANSPORTATION ALTERNATIVES
The transportation objective is to ship the phosphate rock to
local or port destination as efficiently and safely as possible
with minimum disruption. The alternatives selected for
assessment are: 1) Railroad with truck as emergency mode
(Proposed Action); 2) Trucks only; 3) Pipeline to port: and 4)
Conveyor belt.
The presently feasible alternatives for transportation of the
phosphate rock to the port facilities in the Tampa Bay area
appear to be that of railroads and/or trucks. Both the pipeline
and conveyor belt alternatives present the significant problems
of obtaining a continuous zone of right-of-way and/or land
purchase for a route to a port and prohibitive capital costs
for construction. Railroads are established in Central Florida
and they are reliable. The initial capital cost of installing
the railroad to the mine from existing facilities would be
weighed versus operational cost. Presently, rail is the most
economical transportation available because it uses less energy
and is generally environmentally acceptable. Long trains can
disrupt traffic at various intersections with major arteries.
The truck alternative will use more energy, but it is a lower
capital investment and, in some cases, has a higher reliability.
However, it has environmental (air pollution) considerations,
it would contribute to traffic congestion, and it is not known
if the present road systems have the ability or capacity to
handle the traffic.
2.13 ENERGY SOURCE ALTERNATIVES
The objective is to maintain maximum efficiency in energy
conservation while minimizing energy costs and environmental
dis rupt i on.
Energy source alternatives assessed are: 1) Corrmer ci al 1 y
available electric power (Proposed Action); 2) On-site coal,
oil, gas powered generator; 3) On-site nuclear power generator-
*) On-site solar power generator; and 5) On-site hydroelectric
generators.
The only feasible alternative is to purchase the required power
irom a corrmercial producer. This source is practically cost-free
to the miner to build and maintain and is environmental1v
acceptable. }
On-site generation by coal, oil, or gas would have four costly
21
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drawbacks or constraints; the capital cost; the cost of operating
the plant (personnel and fuel cost); valuable mi neral resources
could be covered by the on-site energy plant; i.e., building
and cooling pond area could not be mined for phosphate; and
special measures would have to be taken to insure a nonpolluting
energy system. Regarding nuclear generation, with the exception
of a reduction in air pollution, this alternative has the same
drawbacks as generation by coal, oil, or gas. In addition,
strict control of the fuel and security for fuel waste disposal
would have to be resolved at considerable expense to Swift.
Current solar power technology has not advanced to the point
where sufficient electrical energy could be obtained from the
sun to satisfy mine requirements on a practical, non-
inter ruptab'l e economic basis. None of the streams on the property
are capable of supplying the needed steady water flow to provide
the mine's electrical requirements through hydroelectric
generators.
2.14 NO-ACTION ALTERNATIVE
The no-action alternative would be to not construct the proposed
New Source on the Duette tract and to allow the area to continue
its present day socioeconomic and environmental trends.
Sunmnarized below are general local and regional effects related
to continuance of the present day trends with reference made
to the potential influence of the proposed Swift activity on
these trends.
Soc i oeconomi c - The general socioeconomic effects of the no-
action alternative on the region and local area can be derived
from baseline descriptions and projections of demography,
economics, and community services. These baseline elements
indicate that failure to construct and operate the proposed new
source would exert little effect, positively or negatively, on
general regional or local projections for population growth,
economic growth, or demands for community services and
fac i1i t i es .
The region, and Manatee County specifically, has a considerable
immigration of new residents and an expanding and diversifying
employment base. These trends could be expected to largely mask
any effects exhibited by the no-action alternative on regional
or local demography or employment. The region and Manatee County
would be expected to continue its general trend of population
growth and employment diversification as a result of its favored
"Sunbelt" location. With regard to community services and
facilities, demands would be expected to increase, unaffected
by the status of the Swift proposal. These demands would be
created through general population growth pressures. In any
case, phosphate mines are generally isolated and, by necessity,
are largely self-sufficient in fire and police protection, water
s upply, etc.
The general result of the no-action alternative on socioeconomic
conditions of the region and specifically Manatee County would,
in effect, be one of unrealized potential economic benefits.
22
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Economic benefits of the proposed mine, as represented in Section
5.2 Economics would be about $4.5 million in local property and
state severance taxes with no appreciable effects exerted on
public services, facilities, etc. Additionally, the projected
$25 million annual expenditures by Swift for products and
services would not be realized.
The no-action alternative would, of course, represent the loss
of 61.5 million tons of phosphate rock resource. The annual
production rate of 3 million tons of rock is about 8% of current
Florida phosphate production.
On a greater than local or regional scale, a potential for
positive impact on the United States balance of payments would
be lost due to unrealized sale of the rock product, upgraded
rock products and food products grown domestically.
Envi ronment - The present day general trend for eastern, rural
Manatee County to be largely devoted to agricultural activities
is not expected to change in the foreseeable future. The only
noticeable change to this trend, which is viewed as temporary
in nature, is the approval of two phosphate mines in eastern
Manatee County as Existing Sources. The two approved mines,
neither of which are presently in operation, are located
inrrnediately north and south of the Swift Duette tract.
In the absence of mining on the Duette tract, it is expected
that little physical modification of the tract will occur over
the next two decades. Because of the relatively poor soil
conditions at the Duette tract, it is unlikely that the native
rangeland (cut-over flatwoods), which comprise the majority of
the site, would be rapidly converted to improved agricultural
uses. The practice of clearing native rangeland for production
of watermelon and/or tomato crops for a few seasons may result
in several hundred acres eventually converted to improved
pasture. This conversion of a few hundred acres of the tract
to pasture should not exert significant adverse impacts on the
biology and ecology of the site. As current land clearing
practices for improved agricultural use typically avoid wet soils
due to the impractica1ity of its use as pasture or for row
crops, significant destruction of wetlands on the tract is not
expected.
If additional acreage is cleared for row crops and/or improved
pasture as assumed, irrigation requirements would probably result
in average annual withdrawals of ground-water approaching that
proposed for mining. These withdrawals would be confined
to the dry season only, however, and probably would result in
worst case aquifer drawdowns exceeding those associated with
mining on the tract.
In the no-action alternative, therefore, most if not all
unavoidable adverse environmental impacts, associated with mining
would not occur. The existing natural setting would continue
more or less unchanged. A projected benefit associated with
mining and reclamation, the improvement of soil quality and
productivity potential, would also not accrue.
23
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Swi ft proposes
and practiced
major cornponen
hydrauli c ore
a feed prepara
drying; and sh
(initially) di
as backfill in
3.0 DESCRIPTION OF PROPOSED ACTIVITY
to use equipment and design generally available
by presently operating mines (Figure 3.0-1). The
ts of operation are large walking draglines
transportation via pipeline to a central washer;
tion and flotation plant; wet rock storage and
ipment via rail. Clay and sand wastes are
sposed of in separate areas, with subsequent mixing
reclamation.
Figure 3.0-1 Mining Operation
3.1 MINING OPERATION
Figure 3.1-1 illustrates the proposed mining sequence using two
draglines. The draglines strip overburden for deposit inmined-
out cuts. Exposed matrix is excavated and dumped into a slurry
pit or "well" -- an excavated sump within reach of the dragline.
break! n t t" dl\ects high PreSSure water g^s at the matrix
breaking it into a slurry.
Pumping systems deliver the s1urried matrix to the plant A
pumping system has a "pit pump", the suction of which draws the
matrix slurry in the "well" into a pipeline. The pipeline
transports the matrix slurry at the velocity necessary to
maintain solids suspension.
24
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OU WILL LOCATION
FIGURE : 3.1-1
MASTER DEVELOPMENT PLAN
WITH DRAGLINE SEQUENCE
SOURCE : ZELLARS - WILLIAMS , INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
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3.2 PROCESS DESCRIPTION
Slurried matrix is passed through a wet screening process to
recover the +1 rrm or pebble sized material. Unacceptable pebble
is discarded as waste. Product is stored in pebble bins for
dewatering and quality control analysis prior to shipment or
placement on storage piles.
Underflow fine material from washer screens moves to the feed
preparation area where hydrocylones separate the waste clays
(minus 150 mesh material) from the sand-sized particles, termed
feed. The feed is transported to the flotation circuit.
Flotation is a two-stage process; "rougher" flotation separates
phosphate particles from silica sand by use of a fatty acid
reagent suite, followed by deoiling and "cleaner" flotation by
an ami ne flotation of the sand particles. The sand-sized
product, termed concentrate, is dewatered with water recycled
to the flotation plant.
3.3 PRODUCT DISPOSITION
Wet phosphate rock is received from the concentrate and pebble
dewatering bins at about 16% moisture and stored in open piles.
Concentrate and pebble "rock" products are stored separately by
grade and/or contaminant content to facilitate blending of rock
to meet shipment specificiations, and to maintain inventory.
Rock dewaters to about 13% moisture while in storage with
drainage directed to the plant water system. The storage system
delivers wet rock to either the dryer feed bins or the wet rock
1oadout bi ns.
The last step in processing is drying. Wet rock from the storage
pile is reclaimed according to the blend of pebble and
concentrate required to yield the desired chemical and physical
analysis of the shipment, and delivered to the dryer feed bin
by belt conveyor. The average 13% moisture is reduced to 2%
in the dryer. Moisture is driven off by contacting the product
with a large volume of hot air.
Dry product is transferred to concrete silos for storage.
Conveyors transfer dry rock from the silos to rail loadout
facilities. Approximately 2.5 million tons per year of dry
phosphate rock will move by rail car to Gulf coast ports for
water borne shipment to other U.S. ports or foreign ports in
Mexico, Europe, and Japan. Rail shipment within Florida will
account for the remaining .5 million tons per year.
3.* WASTE DISPOSAL
The beneficiation of phosphate ore generates two solid waste
products: 1) clay or "slimes" consisting of -150 mesh material
and 2) sand tailings consisting of -14+150 mesh material.
Traditionally the two waste materials have been transported to
separate disposal areas, however, recent experimental work has
26
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been conducted on using a mixture of the two wastes to backfill
mine cuts. Swift has committed in their mine plan to use a sand-
clay mix in land reclamation and thereby reduce the need for
traditional separate disposal areas.
At the time the mine becomes operational, Swift will select a
sand-clay mix method based on the economic and technological
feasibility of the choices available.
Based on current experimentation, sand and clay will be mixed
in the approximate ratio of 2.5 to 1 (by weight). The mixture
will be enclosed by levees averaging 14 ft. in height. The
enclosed areas will be filled to 9 feet above natural grade
leaving a freeboard of 5 ft. Filling above ground is necessary
to allow for subsidence of the material as it dewaters and
consolidates, and to facilitate gravity flow within the water
return system. Approximately 5,426 acres are planned for use
as sand-clay-type disposal all but 200 acres of which will be
in mined-out areas.
A 480-acre conventional clay settling area is planned for the
mine. This area will receive all clay wastes generated before
the sand-clay mix procedure becomes operational. The settling
area will remain active throughout the mine life to receive clay
wastes in excess of the sand-clay mix requirements and to serve
as a secondary water clarification and storage area. By the end
of the mine life, the area will be filled to about 25 ft. above
natural grade.
The Duette ore has sand slightly in excess of that required for
the sand-clay mix. Excess sand will be deposited in mining cuts.
The level of filling will be determined by drainage requirements
and overburden available in protruding spoil piles to cover the
sand tailings fill. In the first year of mining, sand tailings
will be used to construct retaining dikes. Thereafter, about
42 acres per year will be backfilled with tailings for a total
of 848 acres.
3.5 WATER MANAGEMENT SYSTEM
Water is used in ore transportation, washing, preparation of
feed, flotation, and waste disposal operations. The majority
of these water requirements will be supplied from the
recirculation system. This initial system consists of the clear
water pond, the clay settling pond, active waste disposal areas,
the beneficiation plant, areas under reclamation, and ditches
interconnecting these components. Water released from clay and
sand wastes is recycled over and over again through this system
until lost due to entrainment in wastes or products or lost to
seepage into impounding embankments. The recirculat ion system
capacity is relatively small during the early years of operation,
requiring makeup water at more variable rates until the surface
water reservoir and clay impoundment reservoir are developed
When the recirculation system is fully operational, approximately
89% of the total water requirements will be recycled water.
27
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The water balance for the proposed reelrculating system is shown
in Figure 3.5-1. Makeup water required to offset system losses
averages 11,207 gpm (16,138,000 gpd). Water within the ore
accounts for 2,207 gpm of this makeup requirement. The remainder
is supplied by ground water pumpage until the fourth year, when
surface water diversion from the East Fork Manatee River supplies
an average of 2,000 gpm to the makeup requirements, leaving 7,000
gpm of ground water.
MOD
4187 6.03
RAINFALL
MATRIX
ENTRAINED WATER.
2307 3.18 \_
7000 10.06
GROUND WATER
2000 2.88 | SURFACE WATER
PROCESS
SYSTEM
EVAPORATION
OTHER
=u>
SAND a CLAY \
ENTRAINED WATER /
SEEPAGE
6PM M6D
2690 3.73
332 0.48
9290 13.38
1380 2.28
DISCHARGE
=t>
1597 2.30
-RECYCLE 604 0.87
NET DISCHARGE 993 1.43-,
I RECYCLE WATER '
l— 9«,800 GPM '
GPM- gal lent p«r minutt
MGD- million gallon* per day
Figure 3.5-1 Process Water Balance
The water balance, mine water system, and
are based on average ore characteristics,
climatology, all of which are likely to vary annually.
reelrculation system
production rates, and
3.6 RECLAMATION METHODOLOGY
Physical Restoration
With the exception of a 100-acre area, all land disturbed by the
operation will be restructured and/or backfilled with waste
materials in conformance with county and state slope
requirements. In sand-clay mix landfills, the exterior levees
and any protruding spoil piles will be graded down. Beyond
conforming to slope requirements, no attempt is planned to cap
sand-clay landfills.
In the clay settling area, the formation of a dry surface crust
will be encouraged by the installation of perimeter and interior
ditches to induce drainage. When the crust has formed, the
retaining dike will be pushed down and any volunteer vegetation
cleared from the area.
In sand tailings landfill areas, the overburden material in the
28
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protruding spoils will be distributed over the landfill to an
average depth of two feet.
In land and lake areas, the spoils will be graded to conform with
terrestrial slope requirements and to form littoral zones
consisting of 12 to 1 subaqueous slopes out to a depth of 6
feet.
In disturbed natural ground areas, all facilities will be
dismantled when mining is complete and the areas graded as
necessary to conform to slope requirements.
In addition to these primary physical restoration techniques,
several special techniques are planned to serve particular
reclamation goals. A three-quarter mile segment of the East Fork
Manatee River is proposed to be restored by creation of an
adjacent floodplain and channel with the same elevation and
gradient as the existing stream.
Shallow basins allowed to form around the drainage outlets in
sand-clay landfills will be retained as rnarsh environments.
Drainage swales will be constructed through adjacent sand-clay
landfills to interconnect these marshes.
A 100-acre land and lake area has been designated as a natural
restoration area. The only reclamation efforts in this area are
to be the topping of spoils to eliminate peaks and the
interconnection of water bodies to provide a flow-through system
at high water stages.
Revegetat ion
About 6,000 acres of reclaimed land will be planted to forage
grasses and legumes. Forage species will be selected to match
the potential productivity of each reclaimed soil type.
Reforestation in upland areas will include mixed plantings of
native species such as water oak, live oak, longleaf pine, slash
pine, etc. in strands approximately 150 feet x 1,000 feet. In
the reforestation of the 55-acre segment of the East Fork Manatee
River, the soil will be stabilized by forage plantings followed
by transplanting of native trees from the existing floodplain.
The transplanted trees will have 2-3 years to establish
themselves before the stream is diverted into the new channel.
Reforestation of four major drainage swales totaling 430 acres
is planned by transplanting potted and bare-root seedlings at
a density of 100 trees per acre. Only native hydric trees will
be used in the plantings.
Two types of reclaimed land will be allowed to revegetate
naturally. The shallow basins created in sand-clay landfills
are expected to be favorable environments to develop marsh-type
vegetation naturally. The minimally reclaimed 100-acre land and
lake area in the northeast portion of the tract will also be
allowed to revegetate naturally as it is bordered on the
southwest by an undisturbed segment of the South Fork Little
Manatee River. The adjacent native vegetation is presumed a seed
29
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source for the natural revegetation.
Reclamation Chronology
Contouring and revegetation of land and lake areas is estimated
to require two years to complete. Backfilling with sand
tailings, capping with overburden, and revegetating will require
about three years. In sand-clay landfills, two years has been
allotted to filling, two years to subsidence and consolidation,
and an additional year to revegetation, for a total of five years
to complete reclamation. Because of the lengthy period required
to form a surface crust, ten years has been allotted to complete
reclamation of the single clay settling area.
30
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DESCRIPTION OF BASELINE, IMPACTS, AND MITIGATING
MEASURES OF THE NATURAL ENVIRONMENT
4.1 METEOROLOGICAL CONDITIONS
Temperature - The average monthly temperature for Tampa, Florida
varies from 61 degrees in January to 82 degrees F in August.
The winter of 1976-1977 was the coldest on record with January,
1977 being the coldest January on record. The minimum average
yearly temperature on record since 1938 was 70.5 degrees F in
1969. The maximum average yearly temperature was 74.3 degrees
F in 1948. The average yearly temperature based on records from
1890 to 1977 was 72.2 degrees F.
Precipi tat ion - Data collected at two locations on the proposed
mine site from 1975 through 1977 indicate an average annual
precipitation of 48.03 inches. The long-term record (1890-1977)
for the National Weather Service station in Tampa recorded an
average annual precipitation of 48.71 inches. The maximum annual
precipitation recorded by the Tampa observation station since
1938 was 70.43 inches in 1957. The minimum for the same period
was 28.89 inches in 1956. Over 50% of the total annual
precipitation occurs during the well-defined rainy season from
June through September which is characterized by isolated
thundershowers during the late afternoon and early evening
hours. The maximum monthly precipitation is in August and the
minimum is in November. Precipitation throughout the remainder
of the year is associated with the passage of frontal systems
through the area.
Evaporation - The Southwest Florida Water Management District
(SWFWMD) cites an evapotranspiration (ET) rate of 39 inches per
year (Water Crop, 1977) based on a study by Cherry, Stewart, and
Mann (1970). A more recent study by Dohrenwend (1977) gives a
rate of 34.84 inches per year. Using the SWFWMD ET rate, the
ET/precipitation ratio for Tampa is 0.80. Using the more recent
ET rate of 34.84 inches the ET/precipi tation ratio is 0.72.
These calculations are based on Tampa's annual precipitation of
48.71 inches.
Open pan evaporation rates from Lake Alfred, Florida average
69.24 inches per year for the period 1971 through 1975. This
is slightly higher than the 60 to 65 inches reported by the U.S.
Weather Bureau (1959) for the areas from 1946-1955. The same
U.S. Weather Bureau document reports the average annual lake
evaporation rate to be between 50 and 52 inches with 60-62%
of this evaporation occurring from May through October.
Dispersion Phenomena - The Tampa wind pattern demonstrates a
strong influence from the land-sea interaction. The winds are
predominantly from the east through the year. The westerly
component is more pronounced during the spring and summer than
in the fall and winter when there is a stronger northerly
component. The average annual wind speed for the period 1964-
1969 was 7.3 knots (3.75 meters per second; 6.3 miles per hour).
Wind speeds of 10 knots were exceeded 17.6% of the time.
31
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Stability data are available only for Tampa. Atmospheric
stability for Tampa is slightly unstable to extremely unstable
22.1% of the time, neutral 37.4% of the time, and slightly stable
to extremely stable 40.5% of the time (NOAA, 1972).
Mixing depth of less than 120 meters occurred about 10% of the
time from 1960 through 1964, and occurred most often from October
through May. The average morning mixing depth for
nonprecipitation cases (1960-1964) was
wind speed through the mixing depth of
The average afternoon mixing depth for
meters with an average wind speed of 7,
(Holzworth, 1972).
493 meters with an average
5.3 meters per second.
this period was 1359
8 meters per second
Episode or stagnation conditions exceeding two day durations
occurred about twice a year from 1960 through 1964. Episodes
exceeding three day durations occurred about once every two years
for the same period (NOAA, Tabulation II, 1968).
Severe Weather - The chances of a hurricane (tropical cyclone
with winds in excess of 74 mph ) entering the Tampa area in a
given year are 1 in 20 (Dunn, 1967). The probability is less
for the proposed mine site. However, the intense rains (normally
5-10 inches) associated with these storms would be likely to
effect the mine site if a hurricane struck the Tampa Bay region.
The proposed mine site lies within a one degree square which had
a total of 43 tornados between 1955 and 1967. During this same
period, statewide, the greatest number typically occurred in June
(Pautz, 1969).
The proposed mine site lies within a one degree square which had
9 hailstorms with hail 3/4 of an inch in diameter or greater from
1955-1967 (Pautz, 1969).
The proposed mine site lies within a one degree square which had
19 wind storms with wind speeds of 50 knots or greater for the
period 1955-1967 (Pautz, 1969).
Tampa has about 90 days per year with thunder shower activity
(NOAA, 1977) and Lakeland has about 100 (NOAA, 1977). The more
severe storms are attended by hail or strong winds which can
inflict serious crop damage (Bradley, 1972).
4.2 AIR QUALITY
In t r oduct i on
The analysis of proposed air quality impact was performed in a
manner consistent with objectives of Prevention of Significant
Deterioration (PSD) and includes results of precons t r uct i on
monitoring activities, control equipment selection to achieve
BACT, emissions estimates and mathematical modeling to insure
conforrnance with PSD increments and National Ambient Air Quality
Standards (NAAQS).
-------
Methodology - The underlying methodology involved computer
simulation of source emissions to determine consumption of PSD
increments, and the estimation of background air quality
concentrations to which source emissions could be added to
determine future conformance with NAAQS. The computer simulation
examined existing and future source contributions, annual and
24-hour averaging times, and the proposed as well as significant
interacting external sources. Background air quality was
developed from statistical analysis of measured data where
necessary. Screening level analysis was used where minimal
impacts were anticipated and confirmed.
For the most part, the impacts are measured on a scale of
conformance with air quality standards that fully encompass
public health, welfare, and aesthetic values.
Emissions Estimates - Emissions from the proposed facility were
estimated fromAP-42 Compilation of Emission Factors (EPA, 1973),
manufacturer performance proposals and data, and projected
operating factors for the proposed activity. The results of
these estimates are provided in Table 4.2-A. The estimates in
Table 4.2-A include both construction and operating emissions.
The construction estimates comprise several elements, each a
major activity period within a span of two years. As the
duration of any individual element may be only six months to one
year, all values taken together display a worst day
representation with all activities overlapping at one time.
Except where noted, the stationary source emissions are most
accurate estimates in the table. The data from which these
estimates were computed formed the basis for modeling source
eff ect.
Baseline
Preconstruction Air Quality - Preconstruction air quality at the
proposed project location was determined primarily from
measurements, and for the case of suspended particulate, by both
measurement and modeling (estimation) methods in accordance with
PSD requirements. Where modeling was used, baseline values were
generally determined for points at maximum pollutant effect that
were identified in the analysis of impacts.
A one year program of preconstruction air quality measurement
commenced in the spring of 1977 and concluded in the summer of
1978 with the purpose of measuring total suspended particulate
matter (TSP), sulfur dioxide, atmospheric fluorides, and
vegetative fluorides. For particulate matter and sulfur dioxide,
the measurements were subjected to statistical analysis (EPA,
1971) to project values comparable to air quality standards.
Results of these analyses are displayed in Tables 4.2-B and
4.2-C. Spatial averages and individual station data indicated
that the existing total suspended particulate matter and sulfur
dioxide levels were below air quality standards by considerable
mar gi ns.
33
-------
Table 4.2-A Project Emissions (Pounds Per Day)
Phase/Pollutant
lemporary/Construction
Site Preparation
Construction
TOTAL
TSP
80
60
140
Fugitive
Dust
--
550a
550a
HC
no
90
200
NOX
20
1.000
1,020
S02
nil
60
60
CO
660
460
1,120
Gaseous
Fluoride
--
--
Operation/Mining and
Processing
Mining 10 850a 11 156 77 50
Wet Rock Storage — l,350a>b
Dryers 551 nil 37C l,819d 206 I85C
Dry Rock Storage
and Transport 279 nil
Transportation
(auto/truck/R.R.) 3 «• 20 46 6 108
TOTAL 843 2,200a'b 68C 2,021 289 343
c
a Refer to text. Fugitive dust emissions include a substantial weight percent of
coarse particulate matter (unlike dryer emissions) that will redeposit relatively
close to the point of emission.
b Analysis of product particle size suggests methodology produces substantial
overestimation (99.98% > 40 urn).
c Pollutant loadings generated by fuel combustion process for equivalent industrial
boiler capacity. Reduced generation and/or removal may be expected in fluidized
bed dryers and wet scrubbing devices.
d Based on field measurements conducted on a similar fluosolids dryer.
34
-------
Table 4.2-B Log TSP Concentration - Frequency Estimates, 1977-78
Station
S-l
S-2
S-3
Average
NAAQS
Pr imar y
Secondar y
Cor r e 1 at i on
Coef f i ci en t
it p n
.98
.97
.98
(.99)a
Second
Maximum
24-Hour
Average
82. 1
68.6
113.5 a
(100. 5)a
83.7
260
150
Annua 1
Geomet r i c
Mean
25.2
20. 1
28.6 a
(27.7)a
24. 3
75
60
Annual
Ar i t hmet i c
Mean
27.9
22. 5
32.9
(31.3)a
(None)
(None)
Florida Standard
150
60
(None)
a - Excluding measurement of 121.5 micrograms per cubic meter
corresponding to gusty winds predominantly from the direction
of a nearby dirt road.
Note: Values in micrograms per cubic meter.
Preconstruction TSP Background - The statistical analysis was
relied upon to develop annual and 24-hour background TSP levels
to support modeling of particulate matter impacts. An estimate
of the statistical geometric mean, 25 micrograms per cubic meter,
was selected as a conservative approximation of the annual TSP
background level. Following the example of a previous EIS (EPA,
1978), an average of the three station 95 percentile values, 55
micrograms per cubic meter, was estimated as the short-term or
24-hour background level.
1977 TSP Baseline - PSD Review requires determination of 1977
Baseline concentration which is defined as the ambient
concentration level reflecting actual air quality as of August
7, 1977, less any contributions from major stationary sources
which corrmenced construction after January 6, 1975. The latter
are charged against available PSD increments. A consequence of
the definition is that the 1977 Baseline is an unmeasureable
abstract quantity which must be determined by modeling. This
quantity was determined for both annual and 24-hour average
conditions using the AQDM and a combination of CRSTER and PTMTP-W
computer codes, respectively, for several locations of worst
effect identified in the source impact analysis.
The annual 1977 TSP Baseline displayed in Figure 4.2-1 reflects
relatively minor influence from the 239 major sources in the 1977
Baseline inventory since there is a 25 micrograms per
background level included in the value. These values
with federal primary and state standards of 75 and 60
per cubic meter, respectively.
cubic meter
compare
micrograms
The 24-hour 1977 TSP baseline displayed in Figure 4.2-2 includes
35
-------
25.6 yg/m
'KEENTOWN
PPTY. BOUNDARY
25.6 yg/m
-f +
25.5 yg/m
ALL VALUES
GREATER THAN
25.5 yg/m3 AND
LESS THAN
BOUNDARY
1-
26.5 yg/m
1982 MAX.PT,
+ l + + fl
ALL VALUES
LESS THAN
25.5 yg/m3
AND GREATER
THAN 25.0 yg/m
25.5 yg/m
PPTY. BOUNDARY
1
FIGURE : 4.2-1
ANNUAL 1977 TOTAL SUSPENDED
PARTICULATE BASELINE
SOURCE : CONSERVATION CONSULTANTS , INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
^•56.8 yg/m
PPTY. BOUNDARY
FIGURE : 4.2-2
SHORT TERM (24 HOUR) 1977 TSP
BASELINE AT LOCATIONS OF MAXIMUM
PROPOSED SOURCE INFLUENCE
SOURCE • CONSERVATION CONSULTANTS , INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
37
-------
two significant points of interest -- the locations of worst case
(highest, second highest) concentration at a maximum point
irrespective of the property boundaries and the comparable worst
case location on a property boundary. The worst case locations
were determined by intensive modeling of many combinations of
sources, worst case meteorologies, and a fairly complex process
of elimination of meteorological conditions not productive of
maximum effect. As with the annual Baseline result, external
sources had relatively minor short-term effect at the proposed
project site inasmuch as the background level represents 55
micrograms per cubic meter of the values shown at maximum impact
locations. These values compare with federal primary and state
standards of 260 and 150 micrograms per cubic meter.
Sulfur Dioxide Baselines
The comparatively low sulfur dioxide emissions produced by the
source suggested a less rigorous screening analysis would
adequately insure conformance with air quality standards. A
substitute baseline value was developed from 1977-78 sulfur
dioxide measurements which included the effect of existing
sources at the proposed site during the period of measurement.
This baseline was developed from the analysis of sulfur dioxide
data (Table 4.2-C) and applied to the impact analysis in a
simplified fashion. The statistical projection for annual sulfur
dioxide baseline was 15 micrograms per cubic meter. This value
compares with federal primary and state standards of 80 and 60
micrograms per cubic meter, respectively. The projected 24-hour
or short-term baseline was estimated .to be 75 micrograms per
cubic meter. This value compares with federal primary and state
standards of 365 and 260 micrograms per cubic meter.
Table 4.2-C Log SO2 Concentration - Frequency Estimates, 1977-78
Second Maximum Annual
Stat ion 24-Hour Average Ar i thmet ic Mean
S-l
5-2
5-3
Average
75.8
79.8
64.5
73.4
12.3
12.5
18.3
14.4
NAAQS
Primary 365 80
Secondary 260 60
Florida Standard 260 60
Note: Values in micrograms per cubic meter
Nitrogen Dioxide Baseline
Measurements conducted by others (ESE, 1975-78) at a similar
rural site approximately six miles from the proposed mine
suggested that area nitrogen dioxide concentrations were of the
order of 10% of the 100 micrograms per cubic meter federal/state
38
-------
standard. Examination of concentrations in nearby
urban/industrial areas indicated that the standard was not
exceeded and concentrations dropped to similar low levels in the
transitions from urban to rural land use. It was also determined
that statistics for other pollutants measured at the mine site,
e.g., sulfur dioxide, satisfied annual EPA guideline criteria
(EPA, 1978A) for a remote source with a reasonable margin. All
facts considered, the annual guideline value for nitrogen dioxide
background (20 micrograms per cubic meter) was determined as a
conservative baseline assumption for this pollutant.
Impact
Total Suspended Particulate - Long-Term Effects - Annual effects
of just the proposed source were determined using the AQDM
computer code. The maximum effect, 1.2 micrograms per cubic
meter, occurs well within the confines of the mine. The highest
property boundary effect, 0.5 micrograms per cubic meter, occurs
on the west boundary. Annual effect at Keentown and the Duette
area are indiseernable for practical purposes.
Annual effect of increment consuming sources are displayed in
Figure 4.2-3. Annual concentration at the point of maximum
effect was estimated to be 1.4 micrograms per cubic meter or
about 8% of the allowable PSD increment. Estimated property
boundary effects ranges from 0.4 to 0.7 micrograms per cubic
meter.
Projected annual 1982 effect of all stationary sources were added
to the annual TSP background of 25 micrograms per cubic meter
to test conformance of the completed facility with air quality
standards. The results are displayed in Figure 4.2-4. The
estimated annual mean at all points of maximum effect were
estimated to be less than 50% of the federal primary and state
standards of 75 and 60 micrograms per cubic meter, respectively.
Total Suspended Particulates - Short-Term Effects - Short-term
effects are the result of an exhaustive analysis of various
proposed source/interactive source group combinations for
meteorological conditions producing highest, second highest
pollutant concentrations. Meteorological conditions were the
result of 5 years of CRSTER analysis for source receptor
distances maximizing upwind source effect and proposed source
effect both at downwind locations on the property boundary and
at locations of maximum effect irrespective of property
boundaries. Computer simulation was performed with the PTMTP-W
computer codes.
Effect of the proposed source alone were determined as follows.
The 24-hour average at the point of maximum effect was projected
to be 12.8 micrograms per cubic meter and the worst case property
boundary concentration was 8.1 micrograms per cubic meter. The
maximum point is well within the property boundaries and very
close to the source cluster. Short-term effect of the proposed
source at Keentown was estimated to be 4.7 micrograms per cubic
meter.
39
-------
- 3056
-3054
-3052
-3050
4
- 3048 • -f- 3
0.6 yg/m kt
PPTY. BOUNDARY^
.. 4
3046
4
- 3044
0.4 yg/m
* KEENTOWN
PPTY. BOUNDARY
0.6 yg/m3
0.4 yg/m"
PPTY. BOUNDARY
-l-
4
4
4 4
r 3
0.7 yg/m
PPTY^ BOUNDARY
TO MYAKKA HEAD
4
4
4-
FIGURE 4-2-3
LONG TERM (ANNUAL) EFFECTS OF
INCREMENT CONSUMING SOURCE
PARTI CULATE EMISSIONS
SOURCE CONSERVATION CONSULTANTS INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
- 3056
-3054
-3052
-3050
-3048
3046
- 3044
26.3 yg/m
DUETTE
4 4-
PPTY. BOUNDARY
26.3 yg/m
26:4 yg/m
PPTY. BOUNDARY
4-
4-
4-
4-
4-
PPTY. BOUNDARY
FIGURE 4-2-4
PROJECTED LONG TERM (ANNUAL)
EFFECTS OF ALL STATIONARY SOURCE
(ARTICULATE EMISSIONS
SOURCE CONSERVATION CONSULTANTS INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
Effect of increment consuming sources is displayed in Figure
4.2-5. Maximum increment consumption was estimated to be 12.8
micrograms per cubic meter or about 35% of the allowable PSD*
increment of 37 micrograms per cubic meter. Increment
consumption at the worst case property boundary was projected
to be 8.1 micrograms per cubic meter.
Projected 24-hour effect of all sources was added to the short-
term background of 55 micrograms per cubic meter as a means of
determining conformance with ambient standards. The results are
displayed in Figure 4.2-6. The estimated concentration at the
point of maximum effect was 69.3 micrograms per cubic meter.
It is recognized that the utility of this estimation is highly
dependent on the estimate of background concentration. However,
consideration of available facts would suggest that maximum 24-'
hour concentrations should generally be less than two-thirds of
the lower of the federal primary and state standards of 260 and
150 micrograms per cubic meter, respectively.
Sulfur Dioxide Effects - Estimates of sulfur dioxide impact from
the proposed source were determined from AQDM and CRSTER analysis
for other pollutants, where possible, since the emission rates
indicated that a screening level of analysis would insure
conformance with standards. Annual average concentration at both
the point of maximum effect and at the worst property boundary
location were projected to be less than 1 microgram per cubic
meter. The 24-hour concentration at the worst property line
location was estimated to be 2.3 micrograms per cubic meter.
Property boundary values are below the PSD levels of significance
of 1 and 5 micrograms per cubic meter, annual and 24-hour
respectively. Results of this analysis combined with the low
baseline level suggest that exceedance of the PSD and NAAQS would
not be possible without other major source development in the
inrmediate area of the proposed mine.
Nitrogen Dioxide - Estimates of nitrogen dioxide impact from the
Proposed Source were determined using the AQDM computer code to
test conformance with both the annual PSD level of significance
and the annual NAAQS standards. Where applicable, non-stationary
source emissions were approximated by an area source situated
along the property boundary where stationary sources would
produce the worst property boundary effect. The worst property
boundary effect of the combined stationary and non-stationary
sources was computed to be less than 1 microgram per cubic
meter. The worst property boundary effect is less than the PSD
level of significance of 1 microgram per cubic meter. Results
of this analysis combined with the baseline value suggest that
exceedance of the NAAQS would not be possible without other major
source development in the irrmediate area of the proposed mine.
Efleet on Soils and Vegetation - While some of the substances
emitted are known to interact with soils and vegetation, ambient
concentrations suggested that gaseous fluoride might be the only
pollutant with potential for serious toxic effect. Trace
quantities of gaseous fluoride are expected from the proposed
facility, but it has been reported in another study that
42
-------
T P
- 3056
,
30S4
3052
•3050
3048
- 3046
-t
.7 yg/m
Jf KEENTOWN
8.1 y g/m
j£ I PPTY. BOUNDARY
,
L . 1 I I
FIGURE 4-2-5
SHORT TERM (24HOUR) EFFECTS OF
PROPOSED SOURCE PARTICULATE
EMISSIONS
SOURCE CONSERVATION CONSULTANTS INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
43
-------
jjjd MAL-fL.J
. » V . _ JJ^/ ,.l
2ND MAX. PT ,
_ L_
61.3 yg/m
PPTY. BOUNDARY
FIGURE 4-2-6
PROJECTED SHORT TERM (24 HOUR)
bFFECTS OF ALL STATIONARY SOURCE
PARTICULATE EMISSIONS
SOURCE CONSERVATION CONSULTANTS INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
JdANATEE COUNTY , FLORIDA
-------
emissions several hundred times greater than anticipated have
had virtually undetecable effect on sensitive vegetation types
near to the source (EPA, 1978).
Effect on Visibility - Visibility effects which are regional
in nature, e.g., produced by photochemical smog, condensation
nuclei, etc., will be affected by the proposed source in
proportion to the magnitude of all other sources, natural and
anthropogenic, which contribute the same substances and/or
physical pollutant forms.
The dryer stack will have a water vapor plume that will be
most visible and persistent during periods of high humidity and
cool temperatures, however, the landscape is not viewed as
characteristically scenic and the presence of a vapor plume
should not particularly affect aesthetic values. Stack heights
have been adjusted to lowest reasonable levels to reduce this
effect to the greatest possible degree.
The mining operations will occasionally function near roadways
and high winds may occasionally entrain and carry dust from
working areas across roadways. While the occurrance should be
infrequent, the effects would be characteristically similar to
those presently produced by agricultural interests, e.g., plowing
and cultivating, in this area. 5
Secondary Growth Effects - Historical patterns and projected land
use suggest that significant population growth and corrmercial
activities will not accompany development of the proposed
activity. Increased energy utilization is an industrial growth
component for which impact has been already examined in
considerable detail by regulatory interests.
Mitigating Measures
The major pollutant sources associated with the proposed activity
are two phosphate rock dryers and the storage, material handling,
and shipping facilities. Left uncontrolled, these operations
would produce a noticeable adverse effect in a large area
surrounding the proposed mining activity. An investigation of
alternate high efficiency control systems indicated wet scrubber
technology offered equivalent or better environmental benefit
along with greatest economy and reliability, and lowest energy
consumption. 57
The phosphate rock dryer control systems are designed to achieve
as great as 99.8% removal of particulate matter (dusts), and
^n'^c/T^1 °f the SUlfUr dioxide and an estimated minimum of
10-20% of the nitrogen dioxides generated in the combustion of
fuel oil (which is necessary to dry the rock). Use of fuel oil
containing no greater than 1.0% sulfur and 0.3% nitrogen will
further reduce greater potential emissions which might otherwise
be released by the proposed source. The storage and shippfn£
facilities and associated materials handling systems will be
equipped with fugitive dust collection systems and control
devices capable of 99.7-99 . 8% particulate matter removal
efficiency. The proposed systems will function to remove a major
45
-------
quantity of particulate matter sizes that have the property to
remain airborne for extended periods and could otherwise travel
considerable distance from the point of release.
4.3 NOISE
Baseline
A baseline noise survey was performed to determine existing sound
levels at the site of the proposed Swift Duette Mine. Noise
measurements were performed at seven existing receptors,
including six peripheral sites and one site in an outparcel
totally enclosed within the proposed mine site boundaries. The
seven sites were zoned special exception land uses and included
residences, a church, and school.
A minimum of two measurements was performed at each site to
determine exceedance levels (Lx) and equivalent sound levels
(Leq) and to estimate the day-night sound level (Ldn), L33.3,
L4.16, and L2.08. Measured and estimated noise levels were then
compared with applicable federal standards.
The U.S. Environmental Protection Agency (EPA) has established
an Ldn of 55 dBA as a minimum requisite to protect public health
and welfare with an adequate margin of safety (EPA, 1974). All
computed Ldn estimates for the monitored sites were at least 3
dBA below the established guideline and the average Ldn was 48
dBA, 7dBA below the guideline.
The U.S. Department of Housing and Urban Development (HUD) has
developed minimum noise standards for new construction sites
(HUD, 1971). The standards are divided into three general
groupings of noise exposure: acceptable, discretionary and
unacceptable. Discretionary exposures may be subdivided into
the categories of normally acceptable and normally unacceptable.
All measurements were within the "acceptable" or "normally
acceptable" categories.
The Federal Highway Administration (FHWA) has specified in FHPM
7-7-3 (FHWA, 1974) standard design noise levels for five activity
Categories (labeled A through E). The residences, school, and
church selected as noise monitoring sites are all included in
activity Category B. The design noise levels for activity
Category B are 67 dBA and 70 dBA for Leq and Ldn respectively.
Measured Leq values were all at least 17 dBA within the FHWA
Category B standard with an average measured Leq of 43 dBA 24
dBA within the standard. The highest estimated Ldn was 52 dBA
18 dBA within the Category B standard and the average Ldn was
22 dBA within the standard.
Impact
Source Measurement
The initial phase of the noise quality impact projection entailed
tield measurement of equivalent sound levels (Leq) and sound
46
-------
exceedance levels (L10, L50, etc.) at existing facilities
representative of the proposed facility. Noise sources
investigated included the dragline and sluice pit, washer and
flotation facility, dryer and bulk loading facility, switch yard,
and land reclamation activities. Source directivity, pure tones,
and background sound levels were evaluated in the monitoring
p r o g r am.
Sound pressure levels as a function of distance were derived for
each source from typical existing source measurements assuming
unobstructed sound transmission (i.e., free field conditions).
The noise level contribution of roadway traffic, both mine and
non-mine related was estimated for the first year of mine
operation (1982) in accordance with the Federal Highway
Administration methods (Gordon, et al., 1971) and Transportation
Noise (Nelson and Wolsko, 1973). Railroad noise levels were
based on EPA's locomotive and rail car noise emission standards
in 40 CFR 201.13.
Impact Analysis
The current EPA guidelines (EPA, 1974) establish annual average
sound level values - an annual exterior Ldn = 55 dBA and an
annual interior Ldn = 45 dBA. Twenty-four hour average sound
levels were estimated and the results evaluated in consideration
of annual variation and mitigative effects of attenuation
contributed by ground cover (Beranek, 1971).
Cumulative noise levels in the vicinity of the property boundary
were conservatively estimated by a series of peak 24-hour Ldn
contours based on free field conditions to serve as a screening
criterion to identify potential problem receptors. The screening
indicates that outdoor noise levels at six receptors near the
site would fall within the annual Ldn = 55 contour (Figure 4.3.-
1 / •
Noise levels adjusted for ground and terrain attenuation exceed
the annual Ldn = 55 criterion at only one sensitive receptor -
the Dry Prairie Baptist Church, Site 1 - where a maximum 24-hour
Ldn of 59 dBA is predicted. Because of the continued movement
of the mining activity, the yearly average Ldn would expectedly
be lower than the maximum 24-hour value.
Among the sources impacting the church, the non-mine related
traffic alone on S.R. 62 in 1982 is expected to generate a 24-
hour Ldn of 57 dBA at the church site. Hence, the non-mine
traffic is the largest single contributor to the total Ldn at
the church, and by itself exceeds EPA's outdoor criterion of 55
dBA.
EPA specifies a yearly average 24-hour equivalent sound level
(Leq) of 45 dBA as requisite to avoid interference with indoor
activities in educational installations (EPA, 1974). The same
criterion may reasonably be applied to churches as well.
Computations indicate a maximum Leq of 44 dB could be expected
inside the affected church and thereby satisfy the EPA's 45 dB
cr i ter i on.
47
-------
H] Dragline A
Dragline B
|:||ij Unmined-Disturb
| |Unmined-Undisturb
led at Property Lint
>55
55
FIGURE: 4.3-1
ESTIMATED DAY-NIGHT AVERAGE
SOUND LEVEL (Ldn) CONTOURS
AT DUETTE MINE DURING OPERATION
SOURCE : CONSERVATION CONSULTANTS , INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT A6RICULTUR&-I '
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
estimated peak houriy Leq values at the church were found to
be within Federal Highway Administration criteria for exterior
and interior noise levels.
Further comparison of peak hourly Leq values with the U.S.
Department of Housing and Urban Development L4.25 and L33.3
maximum criteria indicates that both of these criteria would also
be sat i sf i ed.
Based on the noise monitoring program, there are no significant
noises associated with mine-related activities that could be
considered intrusive because of spectral content or
i ntermi ttency.
Mitigating Measures
The noise impact assessment demonstrated that none of the
sensitive receptors near the proposed mine will be exposed to
noise levels which will interfere with activity or result in
hearing impairment. Therefore, no mitigative measures will be
necessary to protect health and welfare.
Health and safety measures taken by Swift to protect on-site
personnel will comply with the requirements of 29 CFR 1910
(Occupational Health and Safety Act of 1970 and 30 CFR 70 and
71 (Federal Mine Safety Act).
4. it- TOPOGRAPHY
Baseline
Manatee County is located in the southwestern section of the
Florida Peninsula with elevations ranging from sea level along
the Gulf of Mexico and adjacent embayments to about HO ft.
(MSL) in the northeast corner of the county. The land surface
rises monotonously inland from the coast and is moderately flat
with some relief provided by shallow stream and river valleys
and low sandy formations corresponding to ancient sea level
ter races .
The proposed mine site is very flat with ground elevations
ranging from about 125 ft. (MSL) in the north to 90 ft. (MSL)
in the south. The topography is largely a result of stream
dissection on a roughly level marine terrace and scattered small
surface depressions which represent dolines. Figure 4.4-1
presents a topographical mapping of the site. Streams and
drainage basins are described in Section 4.9, Surface Water
Hydrology.
Impact
Mining will significantly alter the site's topography on the
short-terrn through surface strip mining and waste clay disposal
activities. Short term effects are primarily the strip mine land
form of parallel spoil piles protruding from mined pits and dikes
and dams used for waste containment/1 and reclamation.
49
-------
:a >/ Xf^
r-i-r.-V^Ai; r
R.2IE. N.22E.
FIGURE I 4.4-1
EXISTING TOPOGRAPHY
SOURCE : ARDAMAM 8 ASSOCIATES , INC.
U.S. EPA - REGION IV
DRAFT .ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
The long-term, net effects on topography are directly reflected
in the land forms resultant from reclamation activities which
largely return the site to near pre-mining characteristics of
elevation and relief. Sand-clay landfill (5,426 acres) areas
are expected to be near original elevation and have a very
slightly rolling topography with a very low gradient largely
toward the retained, natural watercourses or created lakes.
Tailings landfill will occur on approximately 848 acres and will
result in an essentially flat terrain at an elevation slightly
higher than sand-clay fill areas. Tailing landfill is largely
planned for mined areas that correspond to the major, natural
drainage divides to re-establish pre-mining watershed acreages.
Reclamation of the clay settling area (480 acres), the creation
of lakes during reclamation (474 acres) and the planned
abandonment of approximately 100 acres without substantial
reclamation will create relief and elevation not currently found
on-site. The final land form of the clay settling area will
essentially be a plateau approximately 15 feet above the
surrounding essentially flat terrain. The five lakes created
during reclamation leave a land form not currently found on-
site. A significant after mining deviation from any natural land
forms found in the area will be an approximtely 100 acre area
that will remain essentially un-reel aimed. This area, termed
"wilderness" by the applicant, will result in permanent, parallel
rows of steeply sloped island chains in the northernmost created
lake.
Approximately 2,811 acres will not be mined or the existing
topography disturbed in any fashion.
Mitigating Measures
Mitigating measures for topographical impacts are limited to the
reclamation program which must be considered as part of the
mining plan. On-going land reclamation will limit the number
of acres that will be totally disrupted at any given time to
about 700-800 acres.
4.5 SOILS
Baseline
The surface soils that occur on the proposed Duette mine tract
are predominantly sandy in texture. Approximately 80% of the
on-site soils are classified as poorly drainged. Included in
this classification are the alluvial soils associated with
watercourses, the freshwater swamp soils, and the soils
associated with the shallow ponds on site. The majority of the
poorly drained soils, however, belong to the Leon and Immokalee
series in which drainage is somewhat restricted by the occurrence
of an organic hardpan at a depth of 12" to 42". The remaining
20% of the surface soils are well-drained due to their occurrence
in slightly more upland areas and the absence of an organic
hardpan (Ardaman and Associates, 1975).
51
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The sandy texture gives the surface soils relatively high
permeability (except for the hardpan layers) and low shrink-swel1
potentials. The high permeability, relative scarcity of silt
and clay particles, and very gradual slopes combine to give the
soils low erosion potential.
In their natural state, the poorly drained soils on site have
moderately high to high runoff potentials. When adequate
drainage is provided, these soils are characterized by high
infiltration rates and low runoff potentials. The well-drained
soils on site have low runoff potentials in their natural state.
Except for the soils associated with the wetland areas,
limitations for construction of low buildings are minor and
relatively easily overcome. Limitations on use of the surface
soils for construction of homogeneous pond embankments are
considered severe. The soils can, however, be used in certain
sections of embankment construction provided a core of less
permeable material is provided (Ardaman and Associates, 1975).
From the edapho1ogical standpoint, the on-site soils may be
broadly categorized as acid sands with low natural fertility
(Zellars-Wi11i ams, Inc., 1977). The soils associated with
wetland areas have somewhat higher natural fertility; however,
they have generally not been developed for agriculture due to
the difficulty of draining them. The excessively drained Pomello
and St. Lucie soils are generally considered too droughty for
intensive agricultural use. The Leon, Irrmokalee, Rutlege, and
Ona soils are the soils of greatest agricultural importance on
the site. Though low in fertility and poorly drained in their
natural state, agricultural improvements can and in some cases
have been made on these soils through proper drainage,
irrigation, liming, and fertilization practices. The sandy
texture and relatively low organic matter contents of the surface
horizons give these soils low moisture and nutrient retention
capacities. Consequently, relatively high levels of irrigation
and fertilization inputs are required to maintain their
productivity. On the other hand, the sandy texture gives the
soils good tillage and aeration properties provideing drainage
is adequate.
Impact
The proposed mining operation will disturb the existing soils
on 7,583 acres or approximately three-fourths of the site (Swift
Agricultural Chemicals Corporation, 1978). Strip mining will
totally alter the nature of the existing soils on approximately
6,624 acres. The existing soil profiles in mining areas will
be destroyed and in general the surface horizons will be buried
under layers of either subsurface overburden or waste materials.
Disposal of either clay wastes or a mixture of sand and clay will
effectively bury the existing surface soils on an additional 680
acres of land. Alterations in 279 acres of the existing soils
as a result of construction of the beneficiation plant and
support facilities such as the entrance railroad, mine access
roads, powerline corridors, and pipeline corridors will be less
severe since the soil profiles will not be destroyed.
52
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Waste disposal and physical reclamation techniques will result
in the following three new types of surface soils on the site
(Swift Agricultural Chemicals Corporation, 1978):
Soil Type Acreage
Clay 480
Sand-clay 5,426
Overburden (over sand tailings fill) 848
Total 6,754*
*The remaining 829 acres consist of disturbed native soils
and land and lake areas, the land portions of which will
be composed of overburden material.
Each of the new reclaimed soil types has distinct agricultural
and engineering properties that relate to post-reclamation land
use potenti al.
Due to its fine texture and content of apatite, dolomite, and
feldspar, the clay soil of the reclaimed settling area can be
expected to have excellent natural fertility, high moisture
holding capactiy, and good nutrient retention properties.
However, due to the predominance of clay and the initial absence
of soils organic matter, this soil will have poor structure, and,
therefore, poor tillage and aeration characteristics. Because
of the prolonged subsidence that occurs as the clay dewaters,
building limitations on this soil must be considered severe.
The clay soil should have moderately high to high runoff
potent i al.
Assuming that a homogeneous mixture of sand and clay is achieved
in the ratio 2.5 to 1, the sand-clay soil planned for 5,426 acres
of rclaimed land will fall into a sandy loam classification.
Analytical results (Zellars-Williams, 1977) indicate that the
soil should have good inherent fertility as would be expected
from its high content of phosphatic clay. The clay content
should also impart good moisture and nutrient retention
properties to the soil. Initially, the soil will probably have
poor structure due to the absence of soil organic mater. Tillage
and aeration characteristics should, however, be significantly
better than the clay alone due to the relatively high content
of sand in the so i1.
Sand-clay soils are expected to undergo a period of prolonged
subsidence as the clay dewaters; therefore building limitations
on these soils must be considered severe. The runoff potential
of these soils should range from moderately high to high.
Overburden typically varies in composition depending both on
natural variability and on which strata end up at the surface.
Overburden soils on the reclaimed tract can be expected to
reflect this variability. However, in general, overburden soils
tend to be fairly high in clay and phosphorus content. As a
consequence, they can be expected to have fair natural fertility,
moisture holding capacity, and nutrient retention properties,
53
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though not so good as the clay and sand-clay soils. Soil
structure will be poor initially, but due to the relatively high
content of sand, tillage and aeration properties should be fairly
good. These properties can be expected to improve as soil
organic matter builds up. Overburden soils should generally have
acceptable structural stability for building purposes. The
runoff potential of these soils will vary from moderat ely low
to moderately high depending on the silt and clay content of the
overburden soil in question.
Mitigating Measures
The efforts to provide for productive reclaimed soils are the
primary mitigative measures available to compensate for the loss
of the existing soils. Even with these efforts, the short-term
loss of soils from agricultural use, the initial absence of
oranic matter, i.e. humus in all reclaimed soils, and the
decreased bearing capacity of clay and sand/clay soils relative
to the natural soils must be regarded as unavoidable adverse
impacts of the proposed operation.
The primary mitigative measure to compensate for the short-term
soil loss from agricultural use is to proceed with reclamation
as rapidly as possible. The reclamation plan for the proposed
development calls for sand/clay mix to be the primary physical
restoration technique. Since this type of landfill can be
expected to consolidate much more rapidly than clay alone,
reclamation can proceed more rapidly than with conventional clay
settling areas.
Measures available to encourage the development of soil organic
matter in reclaimed soils include the rapid establishment of a
vigorous vegetative cover. Except for a 100-acre area designated
for natural revegetation, the reclamation plan provides for
revegetation of all reclaimed soils as soon as physical stability
permits and grading to approved slopes is complete. Forage
plantings will account for the majority of the revegetation
effort. Pasture sods, especially those including legumes, are
widely acknowledged to be one of the best known ways of
encouraging soil organic matter accumulation (Buckman and Brady,
1969).
The decreased bearing capacity of clay and sand/clay soils
relative to the natural soils will not hinder agriculural use
of these areas, but may limit other future land use options for
the site. Since long-range plans call for this part of Manatee
County to remain rural in nature, this limitation may not be a
serious adverse impact. However, should land use plans for the
area change, future developers may find it necessary to stabilize
foundations with pilings or utilize other measures that increase
the cost of development.
54
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*.6 GEOLOGY
Baseli ne
The Swift Duette site is located within the southwestern portion
of the Polk Upland physiographic province which lies between the
Ocala Arch to the north and the DeSoto Plain province to the
south (Cathcart, 1963). The site locality is characterized by
a low topographic relief; therefore, the drainage within the site
is relative poor, except near entrenched portions of the East
Fork and North Fork Manatee River. The topographic surface is
marked by circular depressions of various sizes and depths which
represent dolines at different stages of formation (Ardaman and
Associates, 1975). Limestone does not occur near the surface
and sinkholes are not know to occur in the area.
The site does not contain significant surficial structural
features. It is characterized by formations of Tertiary and
Quaternary ages gently dipping to the south or southwest at a few
feet per mile. Surficial deposits vary in thickness from 20 to
60 feet and are predominately composed of fine to medium grained
sands with interbedded and dispersed clays. At a depth varying
betwen 2 and 7 feet below land surface, a fine grained iron-
cemented sand is corrmonly found which hydraulical1y acts as a
semi-confining unit separating two layers of relatively uniform
sands. In general, this semi-confining unit (locally termed
hardpan) is found throughout the property but has been noted to
be absent or thin at several locations. Its thickness varies
from about 2 to 22 feet. Below the hardpan, sands and
interbedded clays are found in thicknesses between 10 and 25
feet. Below the surficial materials is the phosphate matrix,
a clayey phosphatic sand. Below the sand unit is an interbedded
sequence of calcitic dolomite, dolomite limestone and sand/silty
clay 250 to 300 feet thick. These materials represent the
Hawthorn and Tampa formations. The lower portion of the Hawthorn
Formation acts as a permeability barrier between the shallow
aquifer and the deeper Floridan Aquifer. Below the Hawthorn are
more competent rocks of the Tampa, Suwannee, Ocala, Avon Park,
and Lake City 1ithostratigraph!c units cited in order of
increasing depth and age.
The mining section generally occurs within 50 to 100 feet of the
surface and for description purposes can be subdivided into
overburden, ore zones, and bedrock phases.
The overburden is of Pleistocene or Pliocene age and includes
all the material from the surface to the top of the ore zone and
ranges from 20 to 50 feet thick. Surface soils grade quickly
into brown and gray loose clean fine sands 5 to 15 feet thick
and cover the entire mine site. Where the hardpan is near the
surface, it can offer a resistance to digging, hamper root
penetration and downward movement of the water.
The ore zone ranges from 30 to 60 feet thick and averages M
feet. It is composed of friable sands, clayey sands, sandy clay
and clays of Miocene age containing sufficient phosphate
concentrations to constitute its classification as an ore
55
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(Zellars-Wil1iams, Inc., 1977). This unit is assigned to the
upper part of the Hawthorn Formation. With increasing depth
there is a gradational increase in clay and carbonate content.
The ore is sandier in texture than that typical for the Bone
Valley ore of the Central District. The phosphate concentration
and quality is variable both horizontally and vertically and this
creates a geometrically irregular ore zone.
The bedrock represents the base of the mineable zone within the
Hawthorn Formation and is generally recognized by dense and
massive dolomitic limestones, often clayey, phosphatic and
fossi1 iferous. The contact with the ore zone is often
gradational. These lower formations are not amenable to ore
processing as practiced on the more friable overlying materials,
and generally contain smaller concentrations of lower grade
phosphate. The sequence with depth contains dense clayey units
that form an effective aquiclude.
Impact
In mineable areas, the upper formation will be excavated to an
average depth of 50 feet and a maximum depth of 100 feet. During
strip mining the overburden section of sands, clays, and hardpan
will be displaced to spoil windrows within the mining pit, and
the underlying phosphatic ore will be completely removed down
to the "bedrock" layer. These excavated areas will subsequently
be either backfilled with sand and clay process wastes or left
as water-filled areas as described in the reclamation plan. Thus
strip mining results in complete restructuring of the lithologic
character and sequences within the mined area. Formations below
the mining section will remain undisturbed.
Mitigating Measures
Surface mining will cause a change in surficial soils and the
upper bed sequences that comprise the mining section on site.
There is no definable impact on the overall geologic system.
Geological impact, other than those addressed under more specific
titles, i.e., topography, soils, hydrology, etc., would then be
limited, and only unusual distinctive geologic features presently
existing would require investigation. No features of such
ranking are known to occur.
4.7 GROUND-WATER HYDROLOGY
Baseli ne
The primary source of ground water in Manatee County and at the
proposed project site is rainfall which infiltrates into the
ground-water system. The movement of water through the ground-
water system is controlled by the hydrologic and geologic
properties of the two primary aquifers occurring in the area.
The shallow or surficial aquifer consists of a series of sands
and clays. The deep ground-water system consists of a sequence
of confining materials and an underlying thick sequence of
carbonate rocks.
56
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Shallow Ground Water - Shallow ground water at the proposed mine
s i te Ts contai ned Trf the upper, or surficial materials and is
found under both water table and artesian conditions.
The hydrologic properties of the surficial aquifer have been
determined by pump testing and slug, or sensitivity, testing.
Values of transmissivity vary over the property and average
13,000 gpd£ft. Permeability values in general are about 225 to
300 gpd/ft . The similarity of water levels in wells screened
above or below the hardpan layer, indicates the hardpan does not
act as a significant confining layer. Permeability of the matrix
has been shown to be low in comparison to the overlying sands.
The average annual precipitation in Manatee County is
approximately 55 inches per year (NOAA, 1977). Based upon
estimates of evapotranspiration, approximately 15 to 20 inches
per year are available for ground water recharge and streamflow.
Calculations indicate between 1/2 and 5 inches per year are
naturally recharged to the ground-water system with stream flow
from the property being estimated to be about 13 inches per
year .
Water levels in twenty shallow wells, screened either in the
sands above the hardpan layer or those below, vary depending both
upon location on the property and the seasonal effects. During
the wet season, water levels are generally at or near land
surface whereas during the dry season, water levels decline to
about seven feet below land surface. Changes in water levels
in the surficial aquifer are produced by rainfall,
evapotranspiration, leakage into underlying geologic formations
and base flow drainage to streams. No water-level response in
the surficial aquifer has been observed as a result of the 30
to 40 feet of change seasonally occurring in the deep ground-
wa t e r s y s t em.
Precipitation infiltrating the surficial aquifer will move both
vertically into the underlying deep ground-water system and
laterally. Vertical flow is restricted by the confining units
underlying the matrix and lateral flow is restricted due to the
low hydraulic gradients over the proposed project site.
Calculations show the lateral flow through the surficial aquifer
provides a base flow to streams of about 2 million gallons per
day (2.2 inches per year).
On the mine property itself, no shallow wells were found which
use the surficial-aquifer system as a source of drinking-water
supply. One property owner located east of the mine uses the
surficial aquifer for irrigation water and is believed to utilize
this source for drinking water also, as no deep well exists on
this property. Studies indicate that, with the exception noted
above, no wells utilizing the shallow system for drinking-water
supplies were known to exist in the project area at the time of
the inventory.
Deep Ground Water - The deep ground-water system at the proposed
project site consists of the limestones and dolomites underlying
the surficial or water-table aquifer and the phosphate matrix.
57
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This system includes the productive portions of the Hawthorn
Formation and the Tampa, Suwannee, Ocala, Avon Park, and Lake
City Formations and is commonly referred to as the Floridan
Aquifer. Consistent beds of limestone and dolomite (carbonate
rocks) occur from a depth of approximately 400 feet to several
thousands of feet. Of these geological units, the producing
zones for potable supply are found, in order of increasing supply
potential, in the Hawthorn/Tampa, Suwannee, and Avon Park
Formations. The Lake City, Ocala, and portions of the
Hawthorn/Tampa Formations act as semi-confining units retarding
the vertical movements of water in the deep ground-water system.
The Lake City Formation contains interstitial as well as layered
evaporites. The inclusion of the evaporites in the carbonate
rock sequence results in an extremely low permeability of the
Formation. This unit contains highly mineralized water due
principally to the occurrence of the evaporites and also to the
residual presence of salt water associated with the deposition
of the formation. A high degree of hydraulic separation of this
unit from the overlying producing horizons has been determined
by testing at the project site.
Recharge to the deep ground-water system occurs primarily by
infiltration of rainfall into the surficial aquifer and the
subsequent leakage downward through the confining beds overlying
the Floridan Aquifer. The relationship of water levels in the
surficial aquifer and the Floridan Aquifer throughout the project
area is such that downward leakage occurs continuously.
Recharge to the deep ground-water system is not restricted to
the proposed project site but occurs over a large portion of the
regi on.
An inventory of deep wells within approximately two miles of the
proposed project site was made to obtain baseline information
on existing supplies and use in the area. Some existing wells
on the property will continue to be utilized for agricultural
purposes until the proposed mining operations are initiated.
Seven wells were constructed on the property to specific depth
intervals and numerous pumping tests were run in order to
determine both the geologic and hydrologic character of the deep
ground-water system.
Aquifer testing on the proposed project site has provided values
for the transmissivities and/or confining characteristics of the
main hydrologic units. Of significance is the high value of
transmissivity of the Avon Park Formation, the low permeability
of the underlying Lake City Formation, the hydraulic connection
of the Avon Park and Suwannee Formations across the semi-
confining beds of the Ocala Formation and the low leakance value
across the Hawthorn/Tampa Formations. Figure 4.7-1 indicates
the geologic units underlying the property as identified through
test-well drilling at the site and the relationship of the
hydrologic characterisics of the units as determined from both
geologic and pumping-test data. Specific aquifer characteristics
for the various geologic units are also shown in Table 4.7-A.
58
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GEOLOGIC LOG
Li'hokigic Log
: QUARTZ SANO
3 CLAT/SILT
t LIMESTONE
I OOLOMITIC LIME
t DOLOMITE
I CALCITIC OOLOfc
SHALLOW, WATER TABLE AQUIFER
VERY SMALL PRODUCING ZONES
LAYERED WITH CONFINING BEDS
MODERATE
PRODUCING ZONE
LOW PERMEABILITY,
SEMI CONFINING BEDS
VERY LARGE
PRODUCING ZONE
LOW PERMEABILITY
VERY LOW PERMEABILITY,
FIRST SIGN OF EVAPORITES
FIGURE: 4.7-1
SUBSURFACE GEOLOGY
AND
GROUND - WATER SYSTEMS
SOURCE ! WILLIAM F. GUYTON & ASSOC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY . FLORIDA
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Table 4.7-A Aquifer Characteristics of the Producing (Confining) Zones
~~ Aqu i f er (Conf i ni ng-Bed ) Transmi ss i vi ty Leakage-,
Formations ___Thickness (Feet) (GPP/Ft.) Storage (GPP/Ft^)
Hawthorn/Tampa
Suwannee
Avon Park
300
200
500
0001 to
00001*
25,000*
175,000
1,000,000*
770,000^
2,000,000
.003
.003
2
Determined from test data. Refined by use o.f digital modeling.
^Estimated by use of digital model results. Estimated upper and
Water-level elevations in the Floridan Aquifer at the proposed
project site range from 30 to 40 feet above mean sea level at
some times of the year to near mean sea level at other times.
Generally, the direction of ground-water flow at the project area
is westerly, towards the coastline.
As seen in Figure 4.7-2, the seasonal effects of irrigation in
the area of the project site are reflected by variations in the
potentiometric level of the Floridan Aquifer on the order of 30
feet. During the 1ow water-1evel periods of the normally dry
spring months, potentiometric levels in the Floridan Aquifer
decline below sea level in a large area coastward of the proposed
proj ect site.
Impact
Effects of the proposed development of Swift's Duette Mine will
be evidenced in both the shallow and deep ground-water systems.
The effects will result from the mining operations including;
pit dewatering, water-supply withdrawals and the proposed
recharge and reclamation projects. Dewatering of the surficial
materials to facilitate mining will, to some extent, impact the
shallow ground-water system throughout most of the property at
some time during the life of the mine. As the active mining
moves from a mined-out area, dewatering operations, other than
those associated with the recharge project, will cease and water
levels in the surficial aquifer will begin to re-establish
themselves to the previous conditions.
The recharge and reclamation projects will effect both the
surficial and deep ground-water systems. Although the withdrawal
of water for process requirements will effect the deep ground-
water system, very little effect will be noted in the shallow
ground-water system. Ground water from the deep system will be
withdrawn in the south-central portion of the mine property.
Withdrawals will be limited to those rates and locations included
in the consumptive-use permit (No. 27703739) granted by the
Southwest Florida Water Management District (SWFWMD) in
60
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1, 1,
1
—
1 1
.1.1
j
.,1
1
Ink!
hi.
.11 1
i . 1
, I
I
JAN FEB.
AUG SEPT. OCT
1 i l.i I itIJLi it I,, I
MAR APR
FIGURE : 4.7-2
LONG TERM WATER LEVELS
OF
INDIVIDUAL PRODUCING ZONES
SOURCE : WILLIAM F. GUYTON 8 ASSOCIATES
61
US. EPA - REBION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWJEJ ASBI-CJJLTUflAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
September, 1978.
Shallow Ground Water - The surficial, or shallow ground-water
system, as previously described , is a fine to medium sand
aquifer with interbedded and dispersed clays. The average
permeability has been calculated to be about 260 gpd/ft . The
primary effect of the proposed action will be to lower the water
level in the surficial system within the radius of influence
created by both dewatering and recharge wells. Within the active
mining area, the water table will be lowered to the top of the
ore matrix, a maximum of about 50 feet. If significant
permeability exists in the matrix, dewatering operations may
require lowering of water levels into the ore body. The lowering
of water levels in the shallow system will decrease rapidly with
distance from the dewatering wells.
Mining will begin in the southern portion of the property, near
the East Fork of the Manatee River. As this pit is abandoned,
active mining with this dragline will move northward. The
initial mining pit will then be modified for use as a surface
water supply reservoir. Dewatering will precede the mining by
a sufficient time period to preclude delaying dragline
operations, the time being dependent on conditions at the
individual site. The effect of a single dewatering well will
extend a distance of 1,700 to 2,400 feet based upon operation
of 6 months and 1 year respectively.
Tentative recharge-well locations have been presented in a report
entitled "Manatee Mine Recharge Program" prepared by Swift. The
recharge project will effect water levels in the shallow ground-
water system within the radius of influence of each recharge
well. The dewatering and recharge wells will cause a similar
response in the lowering of water levels in the surficial
aquifer. The results of hydrologic testing of the deep aquifer
system beneath the project site indicates sufficient aquifer
permeability to accept the recharged water likely exists in the
Suwannee Formation and certainly within the underlying Avon Park
Format ion.
The proposed reclamation program will return waste clays (slimes)
and tailings sands to the mined-out areas. The majority of these
areas will be filled with a mixture of waste clays and tailings
sands. This method of reclamation may reduce the effectiveness
of recharge wells by decreasing the permeability of the
propert y.
The projected effect of the mine operation on the regional flow
pattern in the shallow ground-water system will be small in
comparison to the effect on-site. On-site flow patterns within
the surficial aquifer will be altered depending on the specific
locations of the recharge and dewatering wells and the location
of the clay, clay/sand, and sand filled areas. Of the three
primary factors involved in changes in the flow within the
shallow ground-water system (precipitation, evapotranspiration,
and leakage), the precipitation and evapotranspiration will be
insignificantly effected.
62
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Vertical recharge (natural leakage plus induced recharge through
recharge wells) will increase during the operation of the mine-
recharge project but is expected to return to baseline conditions
at some time after reclamation is complete if the recharge
program is terminated. The reason for the return to the baseline
conditions is that the vertical permeability of the underlying
Hawthorn/Tampa Formations is the controlling factor of natural
1eakage.
The base-flow component of stream discharge will be effected by
dewatering operations and recharge wells and may also be effected
by the proposed reclamation project. In the proximity of
dewatering or recharge wells, the infiltration capacity will
increase due to the dewatering effect of the wells. The
dewatering will provide additional space within the surficial
materials to capture more of the precipitation than would have
occurred otherwise, resulting in less base flow to streams.
Whereas dewatering and the recharge projects are temporal in
nature, the extent of any effect due to the reclamation project
on the base flow to streams will extend for prolonged periods
of time, and will be dependent upon the permeability of the
replaced materials and the proximiy to the streams. Although
the permeability of the reclaimed areas will be altered to some
extent, the combined surface and subsurface flow from the
property will return to near the baseline amounts. There will,
however, be a change in the distribution of the percentages of
each.
Deep Ground Water - The baseline information regarding the deep
ground-water system describes the aquifer characteristics
determined during the extensive drilling and testing conducted
on the property. Utilizing these characteristics, effects of
the proposed withdrawals can be determined. The primary effect
of withdrawals from the deep ground-water system is the lowering
of the potentiometric surface within the area of influence of
the wel1s.
The schedule of withdrawals is included in the consumptive-use
permit granted by the SWFWMD. This allows for withdrawals from
the deep ground-water system at a rate of 13 million gallons
per day (mgd) for the first 3 years of the mine's operation.
During these 3 years, Swift is required to construct a surface-
water retention area that will provide 3 mgd. Commencing in
the fourth year, the use of surface water will result in a
decrease in the ground-water requirement to 10 mgd. Prior to
the initiation of withdrawals, the SWFWMD permit requires the
construction of sufficient recharge wells to transmit 3 mgd of
water from the surficial aquifer into the deep system. The
effect of the recharge project will be to off-set the withdrawals
from the deep ground-water system by 3 mgd thereby decreasing
the net impact on the Floridan Aquifer.
The withdrawal points (well locations) are shown on Figure 4.8-
1 of the following section. The locations were selected to
reduce the projected effect of the withdrawals outside of the
mine property. The recharge points proposed by Swift are also
-------
shown in Figure 4.8-1. When actually constructed, the recharge
wells may be located at points other than those shown. In
general, however, the locations shown are sufficient for the
projection of effects. Proposed average recharge rates have
been obtained from information included in the Swift DRI Addendum
and the total recharge requirement as specified by SWFWMD.
As proposed in the recharge project portion of the Swift DRI
Addendum, the water in the surficial aquifer will be diverted
to the deep ground-water system by use of recharge or connector
wells. The preliminary design of these wells indicates that
they will be cased to a depth of 150 feet with open hole
extending to 700 or 800 feet. This design should allow the water
to be accepted by the Suwannee Formations, depending somewhat
on the head relationships and formation permeabilities. Both
the Suwannee Formation and the underlying Avon Park Formation
are capable of receiving the expected quantities of recharged
wa t e r.
The effect of the scheduled net withdrawals is at a maximum at
the end of the first three years of operation of the proposed
mine. At this time, the maximum decline of the potentiometric
surface on the mine property is expected to be about 12 feet
and at the closest property boundary about 3.7 feet. These
figures decrease to about 9 and 2.6 feet respectively when
surface water becomes available beginning in the fourth year
and net withdrawals decrease by 3 mgd.
The effect of the proposed withdrawals on the potentiometric
surface is extremely small in comparison to the large seasonal
fluctuation illustrated in Figure 4.7-2. Figure 4.7-3(a) is
the calculated potentiometric surface at the end of the first
3 years of operation (the maximum drawdowns) as added to the May
1978 potentiometric map prepared by the U.S. Geological Survey.
The May map is representative of the dry season and, therefore,
usually representative of the lowest annual potentiometric
surface. A similar map of the wet, or high potentiometric
surface season (September 1977), is shown as Figure 4.7-3(b).
The effect of the scheduled withdrawals from the deep ground-
water system on the regional potentiometric surface is small.
Mitigating Measures
Mitigating measures on the effects resulting from the proposed
mining operations are primarily included in the terms and
conditions of the SWFWMD consumptive-use permit (No. 27703739).
This permit was granted on September 6, 1978, and expires
September 5, 1984. The permit includes details of well locations
and pumpage rates in the deep ground-water system and places
restrictions upon effects in both the shallow and deep ground-
water systems. The permit also requires the construction of a
recharge-well system for the purpose of recharging 3,024,000
gallons per day (average annual) from the unconfined surficial
aquifer and/or secondary artesian aquifer to the Florida
Aqu i f er.
Shallow Ground Water - The primary effect of the proposed action
64
-------
POTENTIOMETRIC SURFACE OF THE FLORIDAN AQUIFER
(a) MAY 1978-LOW HATER LEVEL PERIOD
(b) SEPTEMBER 1977-HIGH WATER LEVEL PERIOD
Original Potentiometric Surface
Generalized Change
Mine Location
FIGURE : 4.7-3 (a) (b)
GENERALIZED CHANGE IN THE
POTENTIOMETRIC SURFACE AS A
RESULT OF A 10 MGD NET
WITHDRAWAL
SOURCE . LEGGETTE , BRASHEARS 8 GRAHAM
__^_^______--
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
on the shallow ground-water system is the lowering of the water
level within the system by the dewatering and/or recharge wells.
The consumptive-use permit and the rules and regulations of the
SwFVMVD limit effects within the shallow ground-water system to
less than 3 feet of lowering outside of property which is not
owned, leased or otherwise controlled by the applicant.
No provisions are included within the permit to monitor water
levels in permanent wells screened in the shallow ground-water
system. Such a monitoring plan would appear to be necessary to
determine the lateral effect of the recharge/dewatering systems
and to determine any change in the effectiveness of the recharge
program as reclamation of the mined-out pits increases.
Likewise, no provision is included which identifies the expected
life of the recharge program. The regional ground-water manager,
the SWFWVD, may wish to extend the program indefinitely as a
mitigative measure for the large withdrawals which are taking
place within the region. The continuance of the recharge program
considerably past the life of the mine will result in a
continuation of the lessening in base flow available.
Deep Ground Water - The primary effect of the proposed action
on the deep ground-water system is the lowering of the
potentiometric surface resulting from the withdrawals of water
for process needs. Paragraph 6 of the consumptive-use permit
limits the total withdrawal from the property to a "maximum
combined average annual withdrawal of 12,960,000 gallons of water
per day, with a maximum combined withdrawal rate not to exceed
20,480,000 during a single day." Mitigating the effect of this
withdrawal is accomplished within the framework of the
consumptive-use permit by requiring the direct recharge of the
deep system with water from the overlying shallow system. The
result of the recharge is to reduce the net withdrawal from the
deep system.
To monitor the effectiveness of the recharge wells and to
ascertain compliance,the permit, provides for flow measurements,
to "be performed on each of the connector wells irrmedi atel y upon
completion of construction and then once a month thereafter
unless otherwise approved in writing by the District Staff".
An additional lessening of the amount of water withdrawn from
the deep system will come as a result of the use of a surface-
water reservoir located on the East Fork of the Manatee River
in the southeast portion of the mine property. The consumptive
use permit requires that "commencing with the fourth (4th) year
of mining operations, the permittee shall decrease its ground-
water withdrawals by withdrawing water from the Storage Basin,
when available".
The permit requirements are sufficient to limit withdrawals from
the ground-water system to amounts and locations which should
not pose any threat to the aquifer.
66
-------
4.8 GROUND-WATER QUALITY
Basel 1ne
Distinct differences occur in the chemical characteristics of
the water in the shallow and deep ground-water systems both on
the property and in the region in general. Chemical analyses
of water samples collected from wells in both aquifer systems
are shown on Tables 4.8-A and 4.8-B. The sampling locations for
the shallow and deep ground-water systems are identified on
Figure 4.8-1. The potable production horizons of the deep ground
water system are underlain by evaporite deposits containing
highly mineralized water and high chloride water is known to
exist in areas along the coast, to the west of the project site.
Shallow Ground-Water Quality - The ground-water quality in the
shallow or surficial aquifer over the project site has been
sampled and analyzed at four locations. Two of these wells were
constructed as part of the testing program carried out by Swift
and two are existing wells; one used for livestock watering and
one for garden irrigation. Figure 4.8-1 shows the location of
these wells.
The chemical analyses of water samples from the surficial aquifer
throughout the region generally show the water to be soft, low
in chloride content except in areas of brackish or saline waters,
and often with relatively high iron concentrations. As seen in
Table 4.8-A, water-quality from Wells North and South Shallow
meets the reconrmended or mandatory drinking water standards
except for hydrogen sulfide, iron, pH and odor. Well North
Shallow also exceeds the reconrmended turbidity standard. Water
samples from Well W-C and W-H also meet the recommended drinking
water standards except for pH and total coliform as seen in Table
4.8-B.
Evidence in the analyses of water samples from the four wells
shows that two, North Shallow and Well W-H, are located at sites
that have been or are presently being fertilized.
Total Coliform reported in water samples from Wells North and
South Shallow are low whereas the count for Well W-C and W-H were
reported as "too numerous to count", indicating the coliform was
many times the mandatory drinking water standards.
Deep Ground-Water Quality - Several zones or hydrogeologic units
comprise the deep ground-water system at the project site and
the region in general. In order of increasing depth are the
Hawthorn/Tampa, Suwannee, Ocala, Avon Park, and Lake City
Formations. With the exception of the Lake City, these
formations, which make up the Floridan Aquifer, and are the
primary sources of potable supply for the majority of
municipalities in the region as well as the source for most
irrigational and industrial requirements. Typically these waters
are relatively hard, clear, occasionally odorous, with low
chloride concentrations except in areas of saline ground waters
near the coast. At the proposed project site, comprehensive
chemical analyses were obtained of water samples withdrawn from
67
-------
Table 4.8-A Ground-Water Analysis Results - Installed Wells
Drinking
Inorganic (mg/1)
C .1 1 c i um
Magncs ium
Sodium
Potass ium
Carbonat e
B i carbonate
Siilfatf
Chlol-1-le
Silica
Hydrr.xf Jt.
Carbon D i oxide
Hvdrt'gcn Sulfldr (H^^) as
Ortho Phosphate
Iron
Copper
Manga m-si1
Zinc
Ar s i'u i c
Ha r i um
Cadmium
Chromium
Lead
Mercury
Nitrate (NO}) as
S liver
Fluoride
Other Properties (mg/1 exc
nH
pn
Total Dissolved Solids
(TDS) at 180° C
Specific Conductance
(micromhos/cm)
Total Alkalinity as CaCO}
Total Hardness as CaCO}
Turbidity (NTU)
Color (PCU)
Foaming Agents
Odor (units)
Organic (mg/1)
K nd i' i n
I. i ndane
Methoxychlor
Toxaphene
Total Pesticide
2-4D
2,4,5-TP
Total Organic Carbon (TOC)
Oil and Crease
Ca
Mg
Na
HCO}
S04
Cl
S 10 •?
OH
CO 2
S
FO/,
Fe
Cu
Mn
7.n
As
Ba
Cd
Cr
Pb
Hg
N
Se
Ag
F
ept as
Watt
Stand
200
125
200
250
250
0.05
0.3
1.0
0.05
5
0.05
1.0
0.01
0.05
0.05
0.002
10.0
0.01
0.05
1.8
•r i
ardi/
W
P
C
E2
E2
E2
E2
E2
F.2
E2
El
El
El
El
El
El
El
El
El
El
Hawthorn
53
19
12
1.48
0
268
2
4
25
0
23.47^7
7.6 U
0:22
0.05
'0.1
<0.05
'0.01
-'0.5
'0.01
<0.01
'0.01
<0.001
0.05
'0.01
<0.01
1.5
Suwannee
57
17
14
1.98
0
195
62
11
25
0
0.07
0.18
<0.1
'0.05
'0.01
'0.05
'0.01
'0.01
'0.01
'O.ooi
0.27
'0.01
'0.01
1.3
Avon
Park
58
17
8.3
1.37
0
168
73
10
14
0
0.09
0.07
'0.1
<0.05
'0.01
'0.5
'0.01
'0.01
<0.01
'0.001
'0.01
'0.01
'0.01
0.7
South
Shallow
3.2
1.0
6.1
0.19
0
12
2
9
4.3
0
0.10 11
0.90
0.31
'0.1
<0.05
'0.1
'0.01
'0.5
'0.01
'0.01
'0.01
'0.001
0.02
'0.01
'0.01
0.2
North
Shal low
19
5.3
4.1
0.62
0
76
3
5
6.2
0
54.93-27
0.3417
7.66
0.74
'0.1
'0.05
'0.1
'0.01
'0.5
<0.01
<0.01
'0.01
'0.001
0.01
'0.01
'0.01
0.7
otherwise noted)
6.5-8.
500
1
15
0.5
3
0.0002
0.004
0.1
0.005
0.1
0.01
5 E2
E2
E2
E2
E2
E2
El
El
El
El
El
El
7.6 ll
252
430
220
209
0.24
2
0.22
10
'0.0001
<0.001
'0.05
'0.001
None
Detected
'0.05
'0.005
1.80
<0.1
7.7 H
284
430
160
212
2.7
5
'0.01
2
'0.0001
<0.001
<0.05
'0.001
None
Detected
'0.05
'0.005
1.75
'0.1
7.9 U
300
500
138
216
1.5
5
'0.01
3
<0.0001
'0.001
'0.05
'0.001
None
Detected
'0.05
'0.005
1.13
'0.1
4.15^/
24
75
10
12
0.3
5
'0.01
10
'O.oooi
'0.001
'0.05
'0.001
None
Detec ted
<0.05
'0.005
5.35
'0.1
6.4 H
72
134
62
70
4.8
5
'0.01
5
'0.0001
'0.001
<0.05
'0.001
None
Detected
<0.05
'0.005
1.68
<0.1
Biological (colonies/100 ml)
Total Coli form
Kecal Coli form
Fecal Streptococci
4
El
10
8
48
<1
'1
r)
Cross Alpha
Radium 226 plus Radium 228
Cross Beta
Tr i t ium
S front ium 90
15
5
50
20,000
8
El
F.1
El
El
El
27.6*0.8
0.0*2.0
357.7*5.4
<0.1
0.0*0.3
3.9*1.8
301.7*5.4
'0.1
4.6*0.4
0.0*1.8
84.6*5.3
<0.2
9.9*1.2
12.1*3.5
338.5*5.4
'0.2
4.3*0.6
7.8*2.4
450.1*5.4
'0.1
U W - World Health Organization, International (1963)
P - U. S. Public Health Service (1962)
C - California State Water Quality Control Board
El - Environmental Protection Agency Primary Standards (Mandatory)
E2 - Environmental Protection Agency Secondary Standards (Recommended)
lj Field measurement
68
-------
Table 4.8-B Ground-Hater Analysis Results - Existing Wells
APRIL 1974
ANALYSIS
Total Nitrogen, mg/liter
Nitrogen as Ammonia, mg N/l
Organic Nitrogen
Nitrate Nitrogen, mg N/l
Nitrite Nitrogen, mg N/l
Total Phosphates as PO^mg/l
Diss. Ortho Phos., PO4 mg/l
Total Residue, mg/l
Non- Filterable Res., mg/l
Potassium, as K mg/l
Iron as Fe mg/l
Zinc as Zn mg/l
Copper as Cu mg/l
Lead as Pb mg/l
Sulfides as h^S, mg/l
Dissolved Oxygen, mg/l
BOD, mg/l
COD, mg/l
pH Laboratory
Total Coliform Colonies
/100ml
Fecal Coliform
Colonies/100 ml
Fecal Streptococci!,
Colonies/ 100 ml (1)
Chlorides, Cl mg/l
Fluorides, Fl mg/l
Silica, Si02 mg/l
Sulfates, SO4 mg/l
Arsenic As, mg/l
Oil and Grease, mg/l
Surfactants (Methylene Blue
Active Substances)
Specific Conductance,
mhosx 10'5at25°C
Pesticides
Herbicides
Turbidity, JCU
Color, Taylor Units
Temperature, Water °C
C
2449
0.29
0.10
0.15
0.03
0.005
0.03
0.02
25
4
0.2
0.20
0.075
0.03
0.041
<0.1
5.2
1.7
11
4.85
TNTC
<1.0
<1.0
9.5
<0.2
2.5
<0.1
<0.02
<0.5
<0.01
15
ND
ND
# *
# #
22.5
H
2454
6.60
0.15
1.45
5.00
0.0023
0.05
0.005
330
4
15.0t
0.09
0.045
<0.01
<0.002
<0.1
7.4
<0.1
15
4.80
TNTC
<1.0
<1.0
40.0+
<0.2
2.4
12.8
<0.02
<0.5
<0.01
170
ND
ND
* *
* *
20.0
1
2455
0.36
0.25
<0.05
0.05
< 0.001
0.01
<0.005
380
3
0.80
0.48
1.520
0.05
<0.002
<0.1
6.9
0.7
15
7.90
TNTC
<1.0
<1.0
9.0
<0.2
9.9
0.2
<0.02
<0.5
<0.01
160
ND
ND
* #
* *
25.5
J
2456
0.48
0.35
<0.05
0.07
C0.001
< 0.005
< 0.005
228
7
1.0
0.36
0.025
0.10
0.139
<0.1
4.9
1.2
22
8.20
TNTC
<1.0
<1.0
14.5
3.0
2.7
0.2
<0.02
<0.5
<0.01
180
ND
ND
**
# *
27.0
K
2457
0.29
0.20
<0.05
0.03
0.003
<0.005
0.01
258
5
0.6
0.19
0.205
0.05
0.005
<0.1
5.8
1.3
15
8.20
TNTC
<1.0
<1.0
8.5
1.0
3.0
<0.1
<0.02
<0.5
<0.01
143
ND
ND
* *
* *
26.0
69
-------
j» N6.RTH-TEST WELL-/r~"f
.* NORTH SHALLOW
i-
.... r--.—.- \^ -JM; x-
'r^^Kfa^
W-K " \
Y-r
/'- /?>.<
A - Proposed Recharge Well
I: / i v/' r /
;' 1\Y >•")-
c < L^^,..^' -"
; r j \f •'
y-^ (.I A, .;
1
x? I
' A
r-—l--.'>
*
V \ A '
PARK *• V-.-''
IAV>M P ? • U *
1 ^.r ) imAvrrHOR
—i-p-^-b-^ £-\ \ -/-- <^—* -
FIGURE . 4.8-1
WELL LOCATIONS
SOURCE : LEGGETTE , BRASHEARS a GRAHAM , INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
the producing horizons of the Hawthorn, Suwannee, and Avon Park
Formations and less comprehensive chemical analyses for the Lake
City Formation. Table 4.8-A contains the results of the
analyses for samples collected above the Lake City formation.
The formations above the Lake City contain potable waters and
ia?e?°Tf«ni«0!l theK6 t0-th£ mandatory or recorrmended drinking
water standards are shown in Table 4.8-A. As evidenced by this
m^lf'tJ ?at!;r withdrawn from the deep ground-water system
meets the standards except for the hydrogen sulfide, odor, total
coliform colonies and gross alpha determinations in the Hawthorn
Formation. Additionally, the hydrogen sulfide and turbidity
plrk Formations0* ^ *" W3ter * rOm either the Suwa™ee or Avon
The Lake City Formation does not contain any appreciable
producing zone due to the existence of interstitial and layered
evaporites. Water from this formation (1740-2000 feet betow land
surface) is highly mineralized and does not meet most drinking-
water standards. Sampling locations used for determining the
6 rU"Watr
nnt6!^ frHU??"Watur *uainY in the deeP ground-water system were
not located throughout the property but rather in the south and
north portions. Figure 4.8-1 shows the well locations.
Impact
In general, the available data indicate that the shallow system
aSar WriCVS S°ft' high in ' r°n and bacteria contenT
The deep system contains water which, except for
, p
wateT standards' meGtS the mandatorv or recorrmended drinking
Effects will be noticed in the shallow ground-water system in
response to the recharge and reclamation projects. Effects due
to mining operations and dewatering are expected to be small in
c ornp a r i son.
The deep ground-water system will be effected primarily by the
anS ahf P^oject' Any effects on this system due to withdrawals
negligible q water-level changes are anticipated to be
Shallow Ground-Water Quality - The dewatering of the surficial
adv.rT °h the ?UrP?Se °f mininS is not expected to cause any
adverse change in the quality of the water remaining in the
rant!!?; f0"16 ™ n°r chan§es wi ] J occur due to the additional
capture of precipitation within the dewatered sands. Likewise
other than changes associated with additional capture ^keW1S6'
rainfall, the recharge project will not cause any change in the
water qua ity. Although the dewatering and recharge pK j ects
will result in an increase in the amount of precipitation that
is captured by the shallow ground-water system, {he grad?ent in
the system will convey this water to either the dewa?e?ing sy tern
or the recharge wells and thence out of the water-table Jystm.
The use of the mined-out pits as storage areas for the waste
clays and tailing sands will have an effect on the wa^^al i ty
71
-------
in the shallow system. The nature of the water quality changes
will depend on the nature of the material placed in the pits.
The amount and kinds of reliable data needed to characterize the
water quality of the waste clays are not available at the Duette
Mine site due to the fact that the mine is not in operation.
However, the clay-storage area (less than 5% of the
property) is not expected to contribute a significant volume of
water to the surficial aquifer system due to its size and the
low-permeability range of the waste clays (.09 to .0007
zpd/ft ). Therefore, changes in the water-quality within the
surficial aquifer as a result of the clay-storage area should
be restricted to its immediate vicinity.
If following mining operations, a pit is filled with tailing
sands, the water quality of the shallow ground-water system is
expected to remain relatively unchanged. This is due to the
nature of the tailings sands. Being predominately silica sands,
the silica content may increase slightly, however, due to the
low dissolution capability of silica, the increase should be very
small. The tailings sands are more permeable than either the
waste'clays or the existing surface soils and, therefore,
precipitation infiltration will increase. This should decrease
the already-low hardness of the water in this system near the
tailings impoundments.
In the majority of the reclaimed lands, the fill material is to
be a mixture of tailings sand and waste clays in an approximate
2 5:1 ratio. This ratio is designed to reduce the permeability
of the tailings sands and add nutrients to the mined-out areas
that tailings alone cannot do. Reliable site-specific data
regarding the chemical character of the water within the
sand/clay mix have not been developed at the Duette Mine site.
One sample collected from the pilot-plant study at the Duette
Mine and data from water decanted from a pond which received sand
tailings and waste clays at Swift's Silver City Mine, however,
may provide some insight as to the quality of the water within
the sand/clay mix at the Duette site. Comparison of water-
quality data from the North and South shal1ow wel1s, with those
from the previous1y mentioned studies indicate that differences
between the quality of the water within the sand/clay mix and
that within the surficial deposits may be seen as increases in
chloride, ortho phosphate, nitrate, fluoride, pH, total dissolved
solids, specific conductance and total alkalinity.
Once the mine begins operation and reliable site-specific data
are available, the actual differences between the water quality
of the various waste products and the surficial deposits can be
refined and quantitative predictions may be made as to the effect
of the placement of these waste products at the Duette Mine.
Although it is not anticipated to be a problem, the potential
for leakage from slurry pipelines, return-water systems and other
transport systems could have an impact on the water quality in
the shallow ground-water system.
Deep Ground-Water Quality - With the exception of water in the
Hawthorn Formation, water in the deep system meets the mandatory
72
-------
drinking water standards and most recommended standards down to
the evaporite zones of the Lake City Formation. The effect of
the proposed action on the water quality of this system will be
due to both the withdrawal of water from the system and the
recharge of water from the upper water-table system.
The potential effects due to the withdrawal of water from the
deep ground-water system include the upconing of highly-
mineralized water found below the producing zones and the lateral
movement of salt water inland from the coast. It is extremely
unlikely that either of these potential impacts will occur at
the Swi ft site.
Upconing of the mineralized water located in the Lake City
Formation requires a driving head and sufficient formational
permeability to force these higher density waters into overlying
formations. At the Swift site there is a substantial upward head
drive from the Lake City to the Avon Park and Suwannee
Formations, however, testing of the deeper formations has proved
the permeability of the Lake City Formation is extremely low in
comparison to the permeabilities of the overlying formations.
Estimates of the quantity of highly mineralized water being
withdrawn during testing on the property of a well open into the
evaporite zones indicated little movement of the deeper waters.
Data illustrating the integrity of the Lake City Formation was
presented in Figure 4.7-2. This figure shows that the head in
the Lake City Formation did not change during the period of
record. Over this same period of time, heads in the overlying
Avon Park and Suwannee Formations exhibit seasonal fluctuations
of about 30 feet.
Calculations of the effect of withdrawals from the deep ground
water system on the inland movement of the salt-water/fresh-water
interface located near the coast are too complex to be done with
much accuracy. In an attempt to determine the maximum effect
on the potential for lateral movement, the use of a volume
displacement model was employed. In essence, this model
discounts recharge to the ground-water system as well as under
flow in the system. The total volume withdrawn from the system
is assumed to be supplied from the perimeter of a circular area
with its center at the point of withdrawal and its initial radius
at the existing interface. Calculations done with this model
place the maximum inland movement of the perimeter at 169 feet
for the 31 years of the mine operation. This movement is
essentially inrmeasurabl e with present knowledge as to the exact
location of the interface and existing technology. Applying this
same model to the annual average volume of water presently
permitted within the area coastward of the mine yields a maximum
movement of the perimeter of about 102 feet per year.
As previously discussed, the SWF^XMD consumptive-use permit
requires the artificial recharge of an additional 3 mgd over the
naturally-occurring leakage at the project site. The source of
the additional recharge is the water-table, or surficial
aquifer. Section 4.7 discusses the quantitative aspects of this
73
-------
requirement and indicates the calculated average recharge rate
per well is about 70 gpm. At this calculated rate, 31 wells
would be required and if possible, the induced recharge may
include water from the matrix. The water-quality aspects of the
recharge program are very complex and variable.
A complicating factor in the prediction of effects resulting from
the recharge project is the reclamation project. Proposed
reclamation measures include the placement of a mixture of waste
clays and tailing sands in some of the mined-out pits. The
reclamation project also proposes the placement of un-mixed
tailings sands and waste clays in other areas. Reclamation of
these mined-out areas by this method will have some effect on
both the quantity and the quality of the recharged water.
Although reliable site-specific data regarding the quality of
the water derived from areas of sand/clay mix are not available
for the Duette site, information is available from Swift's Silver
City Mine. This information indicates that the water from a
sand/clay mix at the Duette site may be expected to meet drinking-
water standards except for fluoride, total dissolved solids and
turbidity.
Mitigating Measures
In general, the major effect in the shallow ground-water system
results from the reclamation project; with secondary effects
being caused by waste-clay storage and the active mining
operations. The deep ground-water system is effected primarily
by the recharge/dewatering projects which directly transmit water
from the shallow system to the deep system by means of wells.
Mitigative measures for the deep ground-water system are included
in the consumptive-use permit granted by the SWFMMD.
Shallow Ground-Water Quality - The primary effects anticipated
within the shallow ground-water system are the water-quality
changes associated with the reclamation project. Secondary
effects include the temporal changes in quality resulting from
the active mining operations and some changes due to the capture
of additional rainfall within the dewatered sands surrounding
dewatering/recharge wells.
Mitigative measures for the temporal effects may include
monitoring the quality of the water being removed from the system
by the dewatering/recharge wells and field inspection of the
return ditches and slurrying pits. The monitoring of water
levels in the system will give some indication of the existence
of mounding near the ditches and pits which may be indicative
of leakage. Mi tigative measures for the potential changes due
to the reclamation project are difficult to devise since the
changes may be of such a nature that their effect on the
environment may not be evidenced for a long period of time.
Deep Ground-Water Quality - The primary actions resulting in
water-quality effects in the deep ground-water system include
the dewatering/recharge projects from the system and the
withdrawal of supply water from the system. The proposed actions
may result in a lowering of the water quality in the deep
74
-------
s y s t em.
The dewatering/recharge projects will connect the shallow and
deep systems allowing water in the upper aquifer to flow into
the underlying Floridan Aquifer. Monitoring of the quality of
the water being discharged from the shallow aquifer is required
by the SWFWMD consumptive-use permit in paragraph 10 j for
various parameters and at a specified schedule. This paragraph
further provides for the cessation of the introduction of the
water from the upper system for cause.
The permit also addresses the potential for upconing and requires
analyses for various parameters or specific schedules for water
from the production wells in the Floridan Aquifer.
As previously mentioned, the permit does not indicate the
expected life of the recharge project. While the mine is
actively operating, the recharged water will enter the area
effected by withdrawals from the supply wells (cone of
depression). About 60-70% will be captured in the flow pattern
to the supply wells. The remaining water will enter the regional
flow system of the Floridan Aquifer.
Due to the location of the proposed recharge wells and the slow
movement of water within the regional system (about 60
feet/year), recharged water from only 2 of the 31 proposed
recharge wells is expected to exit the property during the mine
operation. At the end of the 21-year life of the project, about
98% of the total recharged water will remain beneath the mine
property. When mining ceases, the cone of depression will cease
to exist and all of the recharged water will begin to follow the
regional flow pattern. Due to dispersion and dilution, the
recharged water may become indistinguishable from the natural
waters at the distance of a few miles or less from the property.
The extremely low flow rate in the regional system and the large
dilution factor within the Floridan Aquifer will strengthen the
resource protection already afforded by the District permit.
A determination of the life of the recharge project and the
possibility of the need for off-site monitoring of the deep
system are closely tied. If recharge continues, the change in
water quality down-gradient from the site should be monitored.
If recharge ceases after the reclamation project, off-site
monitoring may not be needed.
4.9 SURFACE WATER HYDROLOGY
Baseli ne
The distribution and circulation of water in the atmosphere, on
the land surface, and in the soil and underlying rocks of the
Duette Mine Site are typical of the Middle Gulf Hydrologic System
as described by Cherry et.al. (1970). This well established
hydrologic pattern is a result of the semi-tropical
climatological regime, the very flat relief, the unconsolidated
quartz sand surficial deposits, and the limestone and dolomite
75
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ppoloeic formations of the region. It is characterized by an
Iverale annual rainfall of about 55 inches (SWFWMD), an average
annual evapotranspiration of 39 inches, an average annual total
surface runoff of 15 inches and an annual aquifer recharge of
between 1/2 and 5 inches.
The 10 394 acre Swift site lies within portions of the watersheds
of the'Manatee River, the Little Manatee River, and the Myakka
River Less than 2.5% of the property, the southeast corner,
drains southward to Wingate Creek, which is a tributary of the
Myakka River. An area on the northwest corner, approximately
13% of the total site, drains to the west into the South Fork
of the Little Manatee River which originates on the site. The
major portion of the property, the remaining 85%, drains either
into the North Fork of the Manatee River or the East Fork of the
Manatee River. The North Fork of the Manatee River enters the
site in the north, exits, re-enters north of the Keentown and
re-exits in the southwest, draining about 39% of the site. The
East Fork of the Manatee River enters in the southeast and exits
across th southwest boundary, draining approximately 46% of the
site. The north and east forks of the Manatee River come
together approximately Smiles southwest of the site, and drain
into Lake Manatee about 10 miles downstream of the mine
property. The Manatee River and Little Manatee River ultimately
drain into Tampa Bay while the Myakka discharges into Charlotte
Harbor. A comparison of the three watersheds which lie within
the site boundaries is presented in Table 4.9-A.
Table 4.9-A Drainage Basin Areas
Watershed
Name
Little
Manatee
River
Total Area
of Watershed
(sq. mi )
211
Area of
Watershed
Within Mining
Site (sq. mi )
2.2
% of Water-
shed Within
; Mining Si te
(percent )
1.0
Area of
Watershed
Upstream of
Mi ne Site
(sq. mi )
3.7
Lk. Manatee
Myakka R.
123
550
13.6
0
11.1
0. 1
20.2
0
Stream flow characteristics in the Central Florida region are
a result of the relatively flat topography, with an average
southwestward sloping gradient of 5 feet/mile and the subtropical
rainfall. Stream bed channel slopes range from 0.5% to about
0.2% resulting in velocities of less than 2.5 feet per second.
Approximately 60% of the total annual average precipitation
results from thunderstorms during the 4 months of June, July,
August, and September. These intense storms of relatively short
duration saturate the surface soils, raise the water table to
the land surface at many places, rapidly increase stream
discharges, and occasionally cause some local flooding. The
rains during the remainder of the year are generally widely
76
-------
spaced with respect to time of occurrence and are of the gentle
f?o"al type. During this period stream flows decrease, the
- " ' y
i, of water per day to streamflow. About 13% of this
gallons of wa^gd drains to the Little Manatee River and about
S or a'pproximfteTy 10 mgd, drains to the North and East Forks
of the Manatee River.
United States Geological Survey (USGS) stream flow records on the
Manatee River, two miles downstream from the confluence of the
Nor?h and East Forks, were analyzed to obtain average maximum
average mean, and average minimum monthly flows for the period
of record from April 1966, through September 197*. Average
monthly extreme flows at the downstream end of the Swift property
we?e determined by assuming that the flow is proportional to the
drainage area raised to the power 0.75, a regional relationship
^veloled from historical records from nine USGS gauging stations
?n connect on with flood plain studies. The results are shown
on Fisure%.9-l. The East Fork of the Manatee River during this
S yea? period, had an average maximum flow of 2*2 mgd, an average
mean flow of
-------
00
fD fD ft) ^P Q <"i <— \
3 fl> 3 O fD 3"
"D O 3 OQ 3 "> fD
— 3- C P) 3 0
i ft) c — -i r*
i— CO .— 00 r+ !-. O
O <-»• >— rf CTOQ
ft) ft) T3 3 fD fD
•— i-t fD OQ fD Q. '"O
t— Q) •* /n
"t o 7? to or ft)
fD 3 r+ ^ V< -,
i— • Q. ft) ft) to
ft) •-• rt- CO r+ O
rt- CO -. 3-3
— ^ O O T3 fD Tfl
O i— 3" 3 fD H i-"
3s O XDO to 3- -j . H, . TJ c
^-J , 1 f > ^- f— — » -. *^
II II II II X) 3" H 3 «-H
CX — j fD t-hr+ O CTtofDi — Q. ft) >— i •
3 CX"I "IfD r)Q. O fD
ft1 1ft) fD Tr-fCCTCO T
"! O fDr-f T ft)i — TTfJ^Hh p,
fD O 3fD fD >— O "i fD O O OQ
^ fD O 33fDOfD"«fD
*"• ^ M> OQft)O"tQ.o2
03X3 O.<00.3
tn •-• r+ fD ft) >-• >-• o C r+
C 3 "IX" fD to r+ fD *— D "i ^~
"• ft> Q. "t fD i— ^a
fD % >— i— ft>O Q-3"O -iv-. fl> l-h Hh ft) O
f < OQ «*> Or+^-ft)
ft) fD Oi-hi-hTO3
T to 3- Q _ (D OS ft)
fD ^-- "i »— O ^- O "~<
M 3 OQOCl-O3"to
(D ^ to ,-«. i~
< n •• »-• to o to
*-• Hti 3 h-h t-h ^
«•+ to OQ O O
3" •• 1 Hh r+ ft)
3- to
fD
AVERAGE MAXIMUM. MEAN AND MINIMUM MONTHLY FLOWS AT DOWNSTREAM END OF SWIFT 1>RO1>6RTY
AVERAGE MINIMUM
MONTHLY FLOW AVERAGE MEAN MONTHLY FLOW AVERAGE MAXIMUM MONTHLY FLOW
(1966- 1974). cf, 11966- 1974). cti (1966 - 1974). cfi
o33o3g§S0 8 i § §
IP ^
> U >
u. "*
It i
y i ?
* M ?
p I j p
— p [— 1-* JL
H * -1
1 i 1
rt i o
111, I s •=
IT > -1 i
T J ^3 1
Is S
! /5 !
VV/ I
111 1
rV^ f
f ?o f
i j Z 3> P
\ ™ Tl
2 C g m o
"™* 3
|I
m
[VJ
* ' • 1
1
1
T" ' J
i
m
L 1 . — ,
1 i
H nJ"J
\ir
-------
data for generalized plots of log Q versus log A for various
desired recurrence intervals were developed. These relationships
were used in conjunction with measured cross sections
and estimated channel
s1 opes,
25 and
roughness to obtain mean annual,
100 year flood elevations for the streams on the Swift property.
The total inundated area for all 'streams within the site is 545
acres for the mean annual flood, 870 acres for the 25 year flood,
and 1,120 acres for the 100 year flood. These are approximate
5, 8, and 11 percent respectively of the total Duette site area.
The peak discharge for floods of varying recurrence intervals
of entry and exit points from Swift's property are presented in
Figure 4.9-2.
PEAK DISCHARGE FOR FLOODS OF VARYING
RECURRENCE INTERVALS AT ENTRY AND
EXIT POINTS FROM SWIFT PROPERTY
5000 40OO 3COO
2000
1000 800 goo 600
900 700
40U 300 PEAK DISCHARGE, cfi 100
Figure 4.9-2 Peak Discharge for Floods of Varying Recurrence
Intervals at Entry and Exit Points
Impact
In order to explain the effects of the Duette mine and plant on
the regional water regime, it is necessary to review the water
management plan. This plan was designed to minimize the use of
well water. Water for the mining areas used to slurry and
79
-------
transport the matrix will be provided from a 200 acre surface
water reservoir and a recirculating system. The reservoir will
be filled during times of high flow from the East Fork Manatee
River. In addition, runoff from active mining areas, roadways,
and the beneficiation plant area will be collected in drainage
ditches and added to the recirculation system. Water from wells
will be used to provide make-up water in the flotation process
only. The recirculation system water supply capacity will be
relatively small during start-up and the early years of
operation, requiring make-up water at a higher rate until the
surface water reservoir and clay impoundment reservoirs are
developed. It is anticipated that a minimum of three years of
operation will be needed before a reasonable storage exists
sufficient to satisfy normal rainfall, evaporation/transpiration
variances and to nullify other losses in the system.
During peak stream flow periods a variable portion of the
discharge of the East Fork Manatee River will be diverted through
an off-channel weir to the surface water reservoir. This water
which will be used to make-up 2.88 mgd of the process demands,
amounts to 25% of the average annual runoff of 11.8 mgd which
comes from the total Duette mine property. The diversion will
not effect low or average flows since it will only occur during
periods of high flow. The historical average maximum monthly
flow of the East Fork Manatee River is 184 mgd for the three wet
months of July, August, and September, while the average mean
monthly flow for the same three month period is 26.5 mgd.
A general 1.6 mgd reduction in runoff from the Swift property
will occur during the mining phase due to the increased area of
water retention bodies on the property, i.e., mined-out pits and
the initial settling area; a 2.6 mgd reduction wi 11 occur due
to deep aquifer recharge resulting from the installation of
connector wells; and a 0.1 mgd reduction in base flows due to
dewatering of mine pits. These quantities, plus the 2.9 mgd
diversion to the surface water reservoir, amount to a total
reduction of stream flow of 7.2 mgd during the active mining
phase. Approximately 1.8 mgd of the reduction will occur in the
North Fork Manatee River, and 5.4 mgd in the East Fork Manatee
River. Thus, the combined average flow of these two tributaries
will be reduced from 22.1 mgd prior to mining, to 14.9 mgd during
mining. This reduction in flow will decrease the discharge into
the Manatee reservoir by approximately 9%.
Flow reductions for the Little Manatee River and the Myakka River
will be significantly less and for a shorter duration (18 months)
due to their smaller areas within the Duette property and due
to the absence of water retention facilities or a process plant
within those areas.
The majority of the water which enters the streams on the Swift
property as base flow comes from ground water stored in the
surficial aquifer within an approximately 2000 foot wide zone
adjacent to the streams. Since mining is not planned within this
zone, except for a three quarter mile segment of the East Fork
Manatee River which will be rechanneled prior to its being mined,
mining will have a minimal effect on base flow. It is estimated
80
-------
that the reduction in base flow resulting from mining will
decrease the average flow of the East and North Forks Manatee
River where they exit the property by 1.0% and 1.5%
respect i ve1y.
The major drainage courses on the mine site will be left
undisturbed by the mining operation, except for a small segment
of the East Fork Manatee River. Reclamation will therefore deal
primarily with the restoration of minor drainage conveyances
which channel water into the major watercourses. Drainage
divides will be created by the placement and contouring of
tailings areas so as to re-establish the area of existing
watersheds.
Analysis of daily rainfall records in conjunction with the
U.S. Soil Conservation Service runoff curve numbers for the
hydrologic soil-cover complexes on the Swift property prior to
development and after reclamation indicates that runoff from the
reclaimed property will be decreased by two to three inches per
year. This decrease is the result of increased impoundments in
lakes and marshes and the sand/clay mix land fills. After
reclamation, the average flows of the East and North Forks
Manatee River where they exit the Swift property will be reduced
approximately 0.7 mgd and 0.6 mgd respectively to values of 12.2
mgd and 8.6 mgd. Although the amount of water detained on site
during rainfall events will increase, peak flows will remain
essentially unchanged.
Mitigating Measures
The reduction of surface runoff by construction and operation
of mined out pits and other water retention structures will be
mitigated by the reclamation of the mined lands to the
topographical land forms which existed prior to mining. This
reduction of runoff offers the benefit of reducing flood peak
d i s char ges.
With the exception of a small segment of the East Fork of the
Manatee River, the major drainage courses of the mine site will
be left undisturbed.
During peak stream flow periods a variable portion of the
discharge of the East Fork Manatee River will be diverted through
an off-channel weir to a surface water reservoir. The use of
this surface water retention basin will result in a reduction
of the ground-water requirement by 3 mgd.
*.10 SURFACE WATER QUALITY
Baseli ne
Introduction - The proposed Swift Duette Mine contains portions
of three major river basins and four watersheds including the
North and East Forks of the Manatee River, the South Fork of
the Little Manatee River, and the Myakka River. Fairly extensive
wetlands border the streams traversing the proposed site;
81
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however, land uses at the mine site are primarily agricultural.
Pollutant loadings of streams in the area arise almost
exclusively from non-point, agricultural sources. There are
presently no industrial or municipal point sources of water
pollutants upstream or in the inrmediate vicinity of the proposed
mi ne site.
Surface water quality is generally subject to daily as well as
seasonal variation. It is closely related to stream discharge
rates which are highly variable in streams on the site.
Significant negative correlations of water quality parameters
with flow occurs for alkalinity, sodium, sulfate, chloride, and
fluoride; hence, as flow increases, the dissolved solids
concentration decreases.
Because the great majority of proposed mine site lies within
the Manatee River drainage basin, this water quality
investigation (and others preceeding it) focused major attention
on the North and East Forks of the Manatee River which converge
and flow into Lake Manatee. Water quality of the South Fork
Little Manatee River is examined in less detail since it drains
a relatively smaller areas, and there will be no intentional
interference with the stream by the proposed activity.
Lake Manatee is the primary potable water supply serving the
majority of the population in Manatee County and a significant
portion of Sarasota County (Tampa Bay Regional Planning Council
(TBRPC), 1978. A study of water quality conditions in major
reservoirs (including Lake Manatee) in the Tampa Bay region was
conducted as part of the Areawide Water Quality Management (AWQM)
Plan (TBRPC, 1978). That study concluded that water quality
in Lake Manatee as of 1975 was good. Acceleration of the natural
eutrophication by excessive nutrient loading was identified as
the major problem threatening the reservoir's watershed. Runoff
from pastures and fertilized cropland is recognized as the major
source of these nutrients.
Data were collected from seven different private and governmental
sources to assess the water quality baseline conditions and to
provide a basis for assessing long-term trends in water quality.
The map of surface water sampling stations (Figure 4.10-1)
indicates locations where pertinent data were available and are
included in the water quality data base.
A sumnary of the pertinent physical, chemical, and
bacteriological parameters is given in Table 4.10-A. All values
that do not conform to either State or Federal standards are
i tali c i zed.
82
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Table 4.10-A Data Summary
oo
GO
PARAMETER
Dissolved Oxygen*
Turbidity (NTU)
Total Suspended
Solids
Color (PCU)
PH
Fluoride
Alkalinity, as CaC03
STATION NUMBER
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
1
5.2
S.4
7.8
1.8
1.0
4.0
7
2
18
122
20
250
6.6
6.0
6.8
0.41
0.27
0.66
38
16
62
2
4.7
2.3
7.5
1.3
0.6
2.5
12
1
150
220
100
Z60
6.3
5.5
7.1
0.43
0.26
0.82
21
7
55
3
5.2
3.5
8.2
1.9
1.0
3.1
7
2
46
153
30
225
6.5
6.0
7.1
0.31
0.18
0.44
36
10
124
4
5.1
4.2
8.5
1.5
1.0
1.9
7
3
33
126
20
230
6.6
6.4
6.9
0.37
0.21
0.58
45
17
110
5
9.6
8.9
10.2
15.5
15.5
15.5
64
60
69
70
70
6.8
6.3
7.3
0.35
0.20
0.50
—
6
3.5
0.4
6.6
7.5
7.5
7.5
19
2
36
70
70
6.7
6.3
7.0
0.35
0.20
0.50
—
7
5.2
2.9
11.5
2.3
0.8
11.0
5
0
21
—
6.2
5.7
6.9
0.34
0.17
0.54
—
8 9
7.
7.3 4.
7.3 11.
4.
—
—
15
0
27
143
80
280
6.
6.6 6.
6.6 7.
0.
0.
0.
14
11
17
7
6
5
4
-
_
6
2
5
21
15
84
10
3.7
0.7
8.3
2.2
0.9
5.9
15
8
29
131
75
200
6.5
6.0
7.5
0.45
0.13
1.05
* All units in miligrams per liter unless otherwise noted.
Italicized numbers indicate variations with State and/or Federal water quality standards.
-------
Table 4.10-A (Continued)
oo
— — - STATION Nl
PARAMETER
Copper, as Cu
Iron, as Fe
Zinc, as Zn
Lead, as Pb
Nitrogen, as N
Total
Phosphorus, as P
Total
Total Nitrogen/Total
Phosphorus Ratio
BOD (5-day)
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
1
<0.13
<0.01
0.3
1.2
0.0
4 2
<0.384
<0.01
1.05
<0.007
0.004
<0.01
0.96
0.23
4.21
0.43
0.24
0.76
2.70
0.60
14.0
1.4
0.3
4.0
2
<0.23
<0.1
1.2
1.7
0.2
3.6
0.08
0.01
0.14
0.016
0.013
0.020
0.72
0.38
0.94
0.50
0.28
0.86
1.72
0.44
2.49
1.2
0.3
2.9
3
0.22
<0.01
0.8
1.7
0.1
7.6
<0.018
<0.005
0.03
0.008
0.007
0.009
0.66
0.48
0.82
0.50
0.24
1.07
1.63
0.68
3.15
1.2
0.3
4.0
4
0.18
<0.01
0.7
1.6
0.0
8.4
1.08
0.07
2.10
0.222
0.006
0.438
1.24
0.34
4.77
0.43
0.24
0.77
3.30
0.56
14.9
1.0
0.4
2.2
5
<0.04
<0.02
0.07
0.27
0.20
0.34
0.018
0.005
0.030
0.018
0.008
0.028
3.95
1.69
6.21
0.20
0.13
0.27
18.0
13.0
23.0
8.0
2.0
16
JMBER
6
<0.03
<0.02
0.04
0.22
0.21
0.23
0.052
0.013
0.090
0.018
0.017
0.018
1.51
0.84
2.18
0.22
0.12
0.31
7.0
7.0
7.0
5.6
1.7
10
7
1.05
0.26
6.15
0.68
0.31
1.60
1.54
0.33
6.41
1.7
0.6
3.7
8
0
0
0.19
0.19
0.03
0.03
<0.01
<0.01
0.85
0.85
0.16
0.16
5.31
5.31
1.5
1.5
9 1
0
<0.013
0 <0.02
0.032 <0.02
0.25 0.14
0.10 0.08
0.45 0.20
0.03
0.01 0.10
0.10
0.0156
0.005
0.039
1.58
0.77
2.40
0.46
0.26
0.68
1.79
0.35
3.59
1.1
0.5
2.0
0.10
.007
.004
.010
1.02
0.42
1.63
0.48
0.43
0.53
2.29
0.79
3.79
2.2
1.0
6.0
Italicized numbers indicate variations with State and/or Federal water quality standards.
-------
Figure 4.10-1 Surface Water Sampling Stations
Long-term and Seasonal Trends -
(Station 9) data were used to e
trends in the upper Manatee River
Manatee County Health Department
evaluate long-term water quality
bas i n.
Kendall '
and Wolf
occur red
sol ids,
biochemi
fluori de
increasi
certai nt
i ncreas i
agr i cult
s distribution-free test for independence (Hollander
e, 1973) was used to determine if significant time trends
in average annual concentrations of total dissolved
total suspended solids, turbidity, dissolved oxygen,
cal oxygen demand, nitrate, ortho-phosphate, and
Only in the case of nitrate could a time trend (either
ng or decreasing) be established with 90% or greater
y. The increasing trend of nitrate reflects the
ng influx of nitrogen to the Manatee River from
ural sources.
Existing Water Quality - A key aspect of the water quality
baseline was an evaluation of the conformance of existing water
quality conditions with State of Florida and Federal criteria.
The recently revised Chapter 17-3 of the Florida Administrative
Code (F.A.C.) -- Water Quality Standards (effeetive March 1,
1979) contains three sets of surface water quality standards
which are applicable to waters affected by the proposed project:
(1) Section 17-3.061, General Criteria, (2) Section 17-3.091,
Class I-A Waters - Potable Water Supplies, and (3) Section 17-
3.121, Class III Waters - Recreation-Propagation, Management
of Fish and Wildlife. Water quality data were also evaluated
with respect to drinking water standards in F.A.C. Chapter 17-
22, Water Supplies.
85
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In addition to comparisons with State standards, variations with
the following Federal water quality criteria and effluent
limitations were examined. The Federal criteria are: (1)
NaT onal Interim Primary Drinking Water Regulations (NIPDWR),
40 CFR Ul (2) U.S. EPA Quality Criteria for Water (1976),
"Redbook" Like F.A.C. Chapter 17-22, the NIPDWR standards apply
only to finished water -- not to raw water sources.
The frequencies with which measured parameters at each station
vary with State and Federal water quality standards and effluent
limitations were itemized. The more significant variations are
surrmarized in the following discussion.
Upper Manatee River Basin: Fifty-six percent of the individual
dissolved oxygen (D.O.) determinations at Stations 1 through
k fell below the State and Federal stream standard of 5.0 mg/1.
During a strearn metaboli sm study (Biology and Ecology Resource
Document), D.O. levels as low as 0.05 mg/1 were measured.
Average BOD. levels at the on-site stations ranged from 1.0 to
1 4 -- too low to explain the depressed levels of dissolved
oxveen The dependence of D.O. on water temperature and stream
velocity (hence, reaeration) are the primary factors contributing
to the seasonal variation in D.O. levels while the metabolism
of stream organisms accounts for most of the diurnal variation.
The on-site data are contrasted by an average D.O. concentration
of 7 7 mg/1 measured by the Manatee County Health Department
in Lake Manatee (Station 9), six miles downstream of the site.
Measured turbidity levels in the on-site were generally low.
On the other hand, the mean organic color values exceeded the
maximum recommended level (75 Platinum-Cobalt Units, PCU) for
potable water supplies at all four stations. Complex organic
compounds originating from decaying aquatic plants is the
probable source of the color.
Corresponding to the low turbidity levels, total suspended solids
(TSS) concentrations at stations on the North and East Forks
are normally low. However, frequency analysis performed with
the limited available data (Surface Water Quality Resource
Document) indicated that TSS concentrations in the North Fork
may be expected to exceed 60 mg/1 6% of the time. Further, 12.5%
of the measured TSS concentrations (3 of 24) exceeded 30 mg/1
while the frequency analysis predicted that 17% may be expected
exceed that level. The results of a similar analysis performed
with TSS data from Stations 1 and 4 on the East Fork indicated
that the 30 mg/1 levels will on the average be exceeded less
frequently in the East Fork - 1.4% of the time - than in the
North Fork.
The analyses support the observation that elevated TSS levels
comparable in magnitude to federal effluent limitations
applicable to phosphate mining operations occur with some
frequency in surface waters on the^proposed site.
Water in the North and East Forks is low in dissolved solids
and characteristically soft as evidenced by the average total
86
-------
hardness range of 41 to 65 mg/1 at on-site stations. Variations
with the State's standard for alkalinity (20mg/l minimum) were
measured frequenty in the North Fork (8 of 20 determinations
were below 20 mg/1) and occasionally in the East Fork (2 of 17
below 20 mg/1). Because of its importance in buffering pH
change, EPA (1976) recorrmends that alkalinity not be further
reduced in waters whose natural alkalinity is below 20 mg/1.
Values of pH below the State's minimum standard for Class III
waters (6.0) were measured only at Station 2 on the East Fork
where 17% of the pH determinations were below 6.0. In spite
of these variations, the observed pH values appear to reflect
natural conditions in the East Fork. Comparable values have
been measured in watersheds adjacent to the Manatee River basin
(EPA, 1978).
Mean fluoride concentrations at Station 1 through 4 (0.30 to
0.40 mg/1) are typical of levels found in undisturbed streams
in west central Florida (EPA, 1978), but are above the levels
found in uncontaminated streams in other areas of Florida
(Ardaman and Associations, 1978). Neither the State Class I-A
(Public Water Supplies) nor NIPDWR standard for fluoride (1.5
and 1.4 mg/1, respectively) was exceeded by any of the measured
concentrations. However, the fluoride standard of 0.8 mg/1 in
F.A.C., Chapter 17-22 (Water Supplies) was occasionally exceeded
in measurements on and downstream of the site. In spite of these
occasional variations in fluoride levels with the State's
finished drinking water standard, fluoride levels in treated
water delivered to Manatee County users have not been found to
exceed 0.8 mg/1.
Average measured concentrations of total phosphorus as P at
Stations 1 through 4 ranged from 0.43 to 0.50 mg/1, considerably
above the 0.070 mg/1 average of river waters worldwide
(Hutchinson, 1975). These elevated levels are consistent with
phosphorus concentrations generally found in central Florida
streams (EPA, 1978). Dissolution of natural phosphate-bearing
minerals and leachate and runoff from pastures and fertilized
croplands are the most likely sources of phosphorus (Ardaman
and Associates, 1978); however, the relative contribution from
each source is not easily determined from available data. EPA
(1976) recognizes a number of naturally occuring phenomenon which
reduce the threat of phosphorus to lake eutrophication including
situations where nutrients other than phosphorus limit plant
g rowt h.
Average total nitrogen concentration at the four on-site stations
ranged from 0.66 mg/1 to 1.24 mg/1. Measured concentrations
in the East Fork were on the average noticeably greater than
in the North Fork due primarily to occasionally elevated organic
nitrogen components at the East Fork stations.
While ordinarily prime determinants of aquatic plant growth,
nitrogen and phosphorus do not appear to limit primary
productivity over most stream courses on the site. Light is
evidently the factor limiting aquatic plant growth on the site
due to the dense canopy of swamp forest overhanging the streams.
87
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The few areas that lack the forest canopy support dense growths
of benthic macrophytes. Nitrogen may become operationally
significant as a limiting factor in these areas.
Average total nitrogen to total phosphorus ratios at stations
in the upper Manatee River basin ranged from 1.63:1 on the East
Fork to 3.30:1 on the North Fork. These N:P ratios are
substantially lower than the 23:1 ratio characteristic of natural
waters in general (Hutchinson, 1944), and more importantly, are
below the 13:1 ratio (of organic nitrogen to total phosphorus)
which EPA (1977) employs as the threshold for nitrogen limited
aquatic systems. Because nitrogen is in relatively short supply
compared to phosphorus, nitrogen is potentially the nutrient
which limits primary productivity in the area's water except
where productivity is limited by other factors (e.g., light).
The average N:P ratio at the head of Lake Manatee is comparable
to those in tributary streams on the Duette Mine site and
indicates that nitrogen functions as the limiting nutrient.
Therefore, changes in nitrogen loading of the Lake potentially
cause corresponding changes in primary productivity and, hence,
eutrophication rates.
South Fork Little Manatee River: Physical water quality
parameters in the South Fork Little Manatee River exhibit similar
patterns to those in the North and East Forks Manatee River.
Stream discharge rates are highly variable; however, the peak
discharge at its exit from the Swift property is only a small
fraction of discharge rates in North and East Forks. The water
is highly colored, and like the North and East Forks, measured
dissolved oxygen concentrations were below the 5.0 mg/1 standard
more often than not.
Four measurements of total suspended solids concentrations at
Stations 5 and 6 on the site were available for the data base.
However, the data suggest that elevated TSS levels are not
uncommon in the segment of the South Fork on the site.
With the exception of pH none of the major cations and anions,
including fluoride and alkalinity, varied with the state
standards for Class III waters. Average pH at the on-site
stations was slightly above the 6.0 minimum recorrmended by the
State and EPA.
The average total nitrogen concentration at Station 7 (1.05 mg/1 )
agrees well with the values observed in the Manatee River basin.
Also, the occasional spikes in nitrogen concentration (6.15 mg/1
maximum) corresponds to large increases in the organic nitrogen
fraction -- the same relationship exhibited in the Manatee River
data. The average measured total phosphorus concentration in
the South Prong watershed (0.68 mg/1) was somewhat above the
average measured in the upper Manatee River basin.
Sutrmary - Occasionally large and/or frequent variations with
State and Federal water quality standards were observed in
measured concentrations of numerous physical, chemical, and
bacteriological parameters in both the upper Manatee and South
-------
Fork Little Manatee River basins. For the most part, these
variations appear to reflect natural conditions in these waters.
Furthermore, the quality of the water has permitted the
development and maintenance of moderately dense and diverse
faunal communities in the streams (Biology and Ecology Resource
Document). While the two river basins are noticeably dissimilar
in terms of their periphyton and macroinvertebrate community
structures, both systems are characterized by "clean" water
conditions and are detrital based.
Impact
Composition of Discharges from Duette Mine - Discharges to
Streams leaving the proposed mine site from the plant water
system are necessary at certain times of the year due to
considerable temporal variation in the region's rainfall
distribution (Swift Agricultural Chemicals Corporation, 1978,
1979). For 59 days during August and September of an average
rainfall year, 1.959 million gallons per day (mgd)will be
discharged from the mining, reclamation, and plant site in the
southeast portion of the property. The discharge will be through
point 002 into the East Fork of the Manatee River (Figure 4.10-
2). Effluent will be discharged for 90 days during August,
September, and October of the average rainfall year to the North
Fork from the clay settling area through point 003 at a rate
of 1.773 mgd.
The composition of effluents from both dicharge points will be
similar to the effluent from Swift Agricultural Chemicals
Corporation's Silver City mine. Since caustic soda and slaked
1 irne will normally be used as neutralizing agents in the proposed
facility in lieu of the arrmon i a used at Silver City, the arrmonia
and total nitrogen concentrations will be less than those
observed in the Silver City effluent. For the purposes of this
impact evaluation the arrmonia concentration in the mine effluent
may be assumed less than the background arrmon i a levels in the
East Fork Manatee River (0.29 milligrams per liter) owing to
dilutional effects of well water additions. It follows that
related nitrogenous compounds would be similarly decreased.
Flotation reagents are used in dilute quantities (Swift
Agricultural Chemicals Corporation, 1978) to separate phosphate
rock from sand particles in the flotation circuits. These
reagents are selected because of their property to preferentially
adhere to phosphate or sand particles and achieve separation
of the two materials. All reagents have preferential affinities
for clay particles; hence, the flotation feed is careful1y washed
to remove all possible traces of clay. Flotation circuits in
new plant designs seek to minimize reagent use to levels not
appreciably exceeding the quantities that adhere to the product
leaving the flotation circuit. Inasmuch as waters discharged
from the flotation circuit join with waters containing clays
from other plant operations, e.g., washing, further opportunity
is provided for residual reagent to form physiochemical
attachment to clay particles. Thus the concentrations of these
substances are expected to be substantially less than reflected
by the dilution ratios referenced above.
89
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R 21 E R 22 E
LECEND
7^- SITES FOB WATER OU»UTr MONITORING
FIGURE : 4.10-2
DISCHARGE POINTS AND
WATER QUALITY MONITORING
STATIONS
SOURCE . ZELLARS - WILLIAMS , INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
The chemicals used in the flotation process are fatty acids,
fuel oil, sodium hydroxide, dilute sulfuric acid, straight-chain
amines and kerosines. These chemicals will form relatively
insoluble complexes, precipitates and/or exhibit non-refractory
characteristics in the environment, i.e., chemically degrades
to simple compounds or molecules.
Comparison of Discharges with Effluent Limitations and
Gu i de1i nes - Of the numerous water quality parameters
investigated in the impact analysis, the nine listed in Table
4. 10-B will be regulated under conditions of the NPDES permit
application for the proposed mine. Expected 30 day average
and daily maximum concentrations are given in Table 4.10-B as
they appear in the NPDES permit application (Surface Water
Quality Resource Document , Appendix B). Historical discharge
data from Swift's Silver City Mine, results of Silver City Mine
comprehensive effluent analysis, and EPA's effluent guidelines
applied to other mining operations in the area were taken into
account in developing the expected discharge levels from the
Duette Mine.
Table 4.10-B NPDES Permit Application Effluent Limitation
ExpectedExpected
Parameter 30-Day Average Dai ly Maximum
pH 0
Temperature (winter), F
Temperature (surrmer), F
Biochemical Oxygen Demand
(5-day), rng/ 1
Total Suspended Solids, mg/ 1
Specific Conductance,
mhos /crn (9 25 C
Copper, mg/ 1
Oil and Grease, mg/ i
Total Phosphorus as P, mg/ 1
55
90
2.9
30
0.01
5
3.0
6.0-9.0
60
500-1000
(m i n . - ma x . )
9.0
EPA has established limits for allowable 30-day average and daily
maximum levels of total suspended solids (TSS) and total
phosphorus, and recommended limits on total fluorides (5.0mg/l
30-day average and 10.0mg/l dai1y maximum) in the proposed mine
effluent. The limitations are typical of permitted mines in
the area, and represent concentrations which may be exceeded,
albeit infrequently in the Duette Mine effluent. Results of
long-term effluent monitoring at Swift's Silver City Mine, which
is representative of the effluent from the proposed mine with
regard to these parameters, suggest that EPA's guidelines for
fluoride and TSS would rarely be exceeded during the life of
the mi ne.
On the basis of Silver City Mine measurements, the expected 30-
day average phosphorus concentration in the Duette Mine effluent
may be expected to exceed the 3 mg/1 effluent limitation at a
frequency of about 14%. The daily maximum limitation of 9 mg/1
91
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may expectedly be exceeded at a frequency of approximately 5%.
The expected daily minimum pH of 6.0 is in accordance with EPA's
effluent limitation guideline applicable to phosphate rock froth
flotation operations in general (40 CFR 436.182). One of 61
measurements of pH in the Silver City Mine data exceeded 9.0
giving an expected frequency of exceedance of 1.6%.
The expected 30 day average and/or daily maximum levels of BOD,
specific conductance, oil and grease, and copper were developed
primarily from the August, 1978 comprehensive analysis of the
Silver City Mine effluent (Surface Water Quality Resource
Document) with tolerances added to allow for the expected
variability in effluent composition.
Swift will regularly monitor effluent water quality at the
permitted points of discharge to assure compliance with NPDES
permit conditions.
Florida Department of Environmental Regulation effluent
limitations for phosphate rock mining and processing (F.A.C.
17-6, effective October 1, 1977) are more stringent than the
federal guidelines with respect to TSS and total phosphorus;
however, the limitations of pH are identical. Whereas, the
state's 30-day average phosphorus limitation of 3 mg/1 is the
same as the federal guideline, the allowable daily maximum of
5 mg/1 is approximately one-half of the limit set by EPA for
the proposed mine. The state's daily maximum limitation was
exceeded in only two of sixty-one separate determinations of
total phosphorus in the Silver City Mine effluent.
On the basis of the Silver City results the state's 30 day
average TSS limitation of 12 mg/1 and daily maximum limitation
of 25 mg/1 may be expected to be exceeded more frequently than
the corresponding federal guidelines (Surface Water Quality
Resource Document).
Comparison of Discharge Water Quality with Ambient Water
Quali ty Standards - Constituents of the plant discharge which
might potentially degrade the quality of the streams leaving
the site were determined through a preliminary screening
process. The approach compares the expected concentrations of
constituents in the plant effluent with ambient state and federal
water quality standards. The discharge of any constituent whose
concentration in the effluent is expected to be below the ambient
water quality standards cannot cause the standards to be exceeded
in the receiving streams (regardless of the quantity of the
discharge) and will not noticeably alter the water quality.
All parameters investigated in the surface water quality baseline
including physical parameters, natural ions, bacteriological
characteristics, trace metals, nutrient composition, and organic
substances were screened in this manner. The parameters were
evaluated in relation to the following ambient water quality
standards and criteria: (1) F.A.C. Chapters 17-3 and 17-22
(Water Quality Standards and Public Water Supplies,
respectively); (2) U.S. EPA Quality Criteria for Water (EPA 440/9-
76-023); (3) National Interim Primary Drinking Water Regulations
92
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(40 CFR 141); and (4) The Central Florida Phosphate Industry
Areawide Impact Assessment Program.
Of the forty-seven parameters investigated for which standards
exist, fluoride and total dissolved solids (and the related
parameter, specific conductance) are the only parameters whose
concentration in the effluent may be expected to exceed ambient
water quality standards within the limits of detectabi1ity of
standard analytical techniques. These parameters, therefore,
merited further investigation.
Predicted Mass Loadings and Concentration - In addition to
fluoride and TDS the parameters, total phosphorus, total
nitrogen, Biochemical Oxygen Demand (BOD), and total suspended
solids (TSS) were selected for further evaluation because of
their potential effects on downstream water supplies. The
effects of each of the six parameters was evaluated by estimating
mass loadings (Ibs/day) and concentrations (mg/1) in both the
North Fork and East Fork after complete mixing with the effluents
from discharge points 003 and 002, respectively. Predictions
were made for the average daily minimum and average daily maximum
stream flow rates during the months of discharge. Average annual
concentrations of parameters were typically used in the stream
loading computations.
Mass loading of the above six parameters in the mine effluent
were based on average discharge rates during a normal rainfall
year. Loadings of total nitrogen, BOD, and TSS were computed
for both 30-day average and daily maximum contaminant levels as
given i n Table 4.10-B.
The predicted total mass loadings and resultant parameter
concentrations after mixing are summarized in Tables 4.10-C (East
Fork) and 4.10-D (North Fork) and compared with the present
cond i t i ons.
East Fork of Manatee River
Nutrients: The largest increase in total phosphorus loading
and resultant stream concentration (0.43 to 4.2 mg/1) is expected
to occur when the minimum stream flow mixes with effluent
containing the maximum expected phosphorus concentration (Table
4.10-C). The elevated phosphorus levels is expected to have
minimal effect on primary productivity rates in the upper Manatee
River basin since naturally occuring phosphorus in the surface
waters is relatively abundant in comparision with the other major
nutrient, nitrogen. Hence, phosphorus is not expected to be
operationally significant as a limiting factor as noted in the
baseline discussion.
Biochemical Oxygen Demand: A 0.8 mg/1 increase in BOD is
estimated at minimum stream flow. This is approximately one
standard deviation from the mean BOD5 value measured just
downstream of discharge point 002. Hence, under present stream
conditions it is not uncommon for BOD5 levels to exceed the level
predicted with the new mine.
-------
Table 4.10-C East Fork Manatee River, Mass Loadings and Concentrations after Mixing
Parameter
Total Nitrogen,
as N
Total Phosphorus,
as P:
Average
Maximum
Fluoride, as F:
Average
Maximum
Biochemical Oxygen
Demand, 5-day
Total Suspended
Solids:
Average
Maximum
Total Dissolved
Solids
Minimum Flow ~ '
Mass
1
Present
.51.7
17.9
17.5
41.7
292
6,170
Loadi ngs
bs/day
With
New Source
43.9
58
156
90.5
172
68.3
636
1,126
13,200
Concentration
mq/1 •
Present
1.2
0.43
0.42
1.0
7.0
'148
With
New Source
1.2
1.6
4.2
2.4
4.6
. 1.8
17
30
355
Maximum -F ow
Mass Loadings
Ibs/day
Present
2,070
717
367
1 ,670
11,700
128,600
With
New Source
2,035
748
846
490
521
1,670
11,870
12,360
135,500
Concentration
mg/1
Present
1.2
0.43
0.22
.1.0
7.0
77
Hi th
New Source
1.2
0.46
0.51
0.27
0.32
1.0
7.2
7.5.
82 .
10
-pa
-------
Table 4.10-D North Fork Manatee River, Mass Loadings and Concentrations after Mixing
Parameter
Total Nitrogen,
as N
lotai rnospnorus,
as P:
Average
. Maximum
Ruoridp a<; F-
Average
Maximum
Biochemical Oxygen
Demand, 5-day
lotai suspended
Solids:
Average
Maximum
Total Dissolved
Solids
Mass Loadings
bs/day
Present
17.6
13.3
•
8.3
32.0
187
3,360
witn
New Source
24.0
50.2
139
77.5
152
56.9
525
969
10,600
Concern
m
Present
0.66
0.50
0.31
1.2
7.0
126
tration
/I
With
New Source
0.91
1.9
5.3
2.9
5.7
2.1
20
37
402
Maximum
Mass Loadings
Ibs/dav
Present
732
555
344
1 ,330
7,760
139,800
With
New Source
737
590
679
413
487
1,350
8,092
8,535
147,000
MOW
Concentration
ma/1
Prpcpnf
0.66
0.50
0.31
1.2
7.0
126
With
new oUUrCc
0.66
0.53
n fii
0.37
n A.&
U . 44
1.2
7.3
7 7
132
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Fluoride: Under conditions of average maximum daily stream flow
the fluoride concentration in the East Fork was estimated to
increase from the 0.22mg/l background level to 0.27mg/l at
the average mine effluent loading and to 0.32 mg/1 at the maximum
effluent loading. Both resultant concentrations are well within
the State's General Criteria for fluoride (10mg/l) applicable
to Class III fresh waters and meet, as well, state and federal
criteria for drinking water supplies (1.5 and 1. 4 mg/1 ,
res pect i ve1y).
At the average minimum daily stream flow during August and
September, the fluoride concentration after mixing will remain
within the state General Criteria for fluoride applicable at
the poi nt of mi xing.
At the recommended maximum effluent fluoride level of 10 mg/1
and minimum stream flow, a resultant fluoride level of 4.6 mg/1
at the point of mixing could be expected - less than half of
the applicable ambient water quality standard.
Taking into account the substantial dilution of the elevated
fluoride concentration between the point of discharge and the
head of the reservoir, the fluoride concentration at Station 10
was estimated at 1.7 mg/1, approximately 13% above the State's
allowable of 1.5 mg/1 for Class I-A waters (Surface Water Quality
Resource Document). Some reduction in the estimated 1.7 mg/1
concentration could be expected by runoff and base flows to the
reservoir from the substantial area downstream of Station 10.
The effect of this additional dilution would be to reduce the
fluoride level at the Manatee County water plant intake to within
the state's standard for public water supplies.
Total Suspended Solids: The difference in total suspended solids
(TSS) concentrations with and without the new mine will be
minimal at high stream flow. The background TSS frequency
analysis (Surface Water Quality Resource Document) indicates
that TSS levels in excess of 17 mg/1 - the concentration
resulting from the expected 30-day average effluent discharge
- may be expected in the natural stream 8% of the time. The
same analysis indicated that the predicted stream TSS
concentration of 30 mg/1 resulting from the maximum effluent
TSS concentration of 60 mg/1 will on the average be exceeded
1.4% of the time under natural stream conditions. The stream's
present frequency of exposure to elevated TSS levels is not
expected to be appreciably altered by the infrequent occurrence
of the hypothesized worst case discharge conditions.
Total Dissolved Solids: At minimum stream flow, discharges from
the mine will result in a 140% increase in TDS concentration.
However, the maximum predicted concentration of 355 mg/1 is
within the 500 mg/1 monthly average standard for Florida's Class
I-A waters, i.e., potable water supply.
At the average maximum stream flow dissolved solids will increase
by 6% over background levels.
North Fork of Manatee River - The minimum average flow of the
96
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North Fork at point of discharge 003 is approximately 64% of
the minimum flow in the East Fork at discharge point 002. Since
the discharge composition and flow rates from the two points
are nearly the same, the effect of the discharge on the water
quality of the North Fork is expected to be somewhat greater
than the effect on the East Fork. In spite of this difference,
none of the State's water quality standards applicable to the
North Fork -- a Class III water -- will be exceeded over the
investigated range of stream flow conditions.
Nutrients: Under worst case conditions of minimum stream flow
and maximum effluent concentration the estimated increase in
the phosphorus level is 4.8 mg/1 at the point of mixing. While
the projected increase in phosphorus under this extreme condition
is substantial, the predominant role of nitrogen as the growth
limiting nutrient minimizes the impact of the phosphorus loading
on the stream water quality.
At the maximum stream flow the estimated elevation in phosphorus
concentration will be substantially less, increasing by 6% over
background at the average effluent phosphorus concentration and
20% at the maximum concentration.
Biochemical Oxygen Demand: A 0.9 mg/1 increase in the stream
BOD,- concentration is predicted for the minimum stream flow
condition. The resultant concentration of 2.1 mg/1 is well
within the range of observed BOD^ background level at Station
3 on the North Fork. Virtually no change in the BOD,-
concentration will occur at the maximum stream flow.
Fluoride: At minimum stream flow and average effluent fluoride
loading the fluoride concentration is estimated to increase from
0.31 to 2.9 mg/1. At the maximum effluent fluoride loading,
the concentration in the North Fork may be expected to increase
to 5.7 mg/1 at the point of mixing. Both resultant
concentrations remain within the allowable 10 mg/1 for Class
III wa t e r s.
Total Suspended Solids: At the average minimum stream flow,
TSS concentrations after mixing are estimated to range from 20
mg/1 at the average effluent TSS loading up to 37 mg/1 at the
maximum discharge concentration. While the latter value is
considerably greater than the average TSS concentration of 12
mg/1 observed in the North Fork at its exit from the Swift
property (Station 3, Figure 4.10-2), it is well within the range
of 1 to 150 mg/1 measured at Stations 2 and 3 on the North Fork.
TSS levels in excess of 20 mg/1 are expected to occur on the
average about 23% of the time in the North Fork under natural
conditions. Hence, the expected average TSS loadings from the
mine will not result in abnormally high TSS levels in the river.
Total Dissolved Solids: A substantial increase in the TDS level
is likely under minimum stream flow conditions. Nevertheless,
the predicted resultant concentration of 402 mg/1 is well below
the 1000 mg/1 maximum level allowed by the State's Class I-A
(Public Water Supply) standard and satisfies the 500 mg/1 monthly
average criteria as well.
97
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Hypothetical Failure of Clay Settling Area Embankment
Introduction: Evaluation of a hypothetical failure of the clay
settling area embankment on the water quantity, quality, and
biology of the receiving waters and adjacent wetlands is
sunrmarized below beginning with a description of the event and
a brief discussion of its probability of occurrence.
The impact analysis was predicated on a ground-level break in
the settling area embankment at the end of the third year of
mining. At that time, the 480 acre settling area will be filled
to capacity with approximately 23 feet of waste clays covered
with 2 feet of clarified water. Two points of failure were
considered separately - one in the west wall of the embankment
in the vicinity of the steepest slope between the settling area
and the streambed of the North Fork, and a second in the south
wall at the point nearest the East Fork.
An estimate of the probability of the embankment failure (Ardaman
and Associates, Inc., 1979) was based on the average value for
annual risk of a modern dam failure (approximately 1 in 10,000)
adjusted for hydrologic and structural conditions unique to the
proposed settling area. The most conrmon causes of dam failure
- overtopping during large floods, subsurface erosion,
earthslides, and earthquakes, in order of decreasing probability
- are all less likely to occur to the proposed embankment than
to an average modern dam for the following reasons: accurately
predictable peak water levels; favorable soil and seismic
conditions; uniform embankment and foundation section; and the
rigorous design and inspection requirements of Chapter 17-9 of
the Rules of the Florida Department of Environmental Regulation.
Cumulatively, the above factors reduce the annual risk of failure
to about one chance in 100,000 or one-tenth the probability of
a clear water dam failure.
Water Quantity Impact: The primary concern with respect to water
quantity impact is the potential reduction in safe reservoir
yields of Lake Manatee and the proposed Beker reservoir. The
safe yield of Lake Manatee before and after the hypothetical
waste clay spill was evaluated for the present minimum reservoir
operating level of 28 feet Mean Sea Level (MSL), and for the
proposed minimum operating of 21 feet MSL (Ardaman and
Associates, Inc., 1979). In its present condition, the safe
reservoir yields for Lake Manatee at the 28 feet MSL and 21 feet
MSL operating levels are 29.7 and 34.2 million gallons per day
(mgd), respectively.
The reduction in safe yield was predicted for two levels of
percent solids in the released clays - 18.2% and 23.6% - as
measured in samples of thickened clay from pilot plant runs on
matrix from the proposed site. Percentage reductions in safe
yield of Lake Manatee due to the spill were estimated to range
from 4-8% at the 21 feet operating level and 4-9% at the 28 feet
1 evel .
The impact of a hypothetical failure in the south wall of the
embankment of the proposed Beker Reservoir on the East Fork,
98
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Manatee River was similarly evaluated using an initial solids
content of 18.2%. The results indicated a probable reduction
in safe reservoir yield of about 1%.
Further conclusions of the impact evaluation with respect to
surface water hydrology are summarized below:
o Waste clay from the spill will be contained within the 100
year floodplain of the Manatee River.
o The increased water level in Lake Manatee after a hypothetical
spill would be less than two feet and would pose no danger to
the dam,intake structures, or spillway structure.
o Erosion of the clay waste by rainfall runoff during the two-
month period after a spill while vegetation is being re-
established, will result in increased suspended solids
loadings of approximately 700 ppm. This amount will not cause
any significant increase in sediment load within the
reservoi r.
Water Quality Impact: Evaluation of the impact of the
hypothetical settling pond failure on stream and reservoir water
quality was subdivided into six areas or phases of potential
impacts: (1) effects on stream water quality, (2) short-term
effects on the Lake Manatee Reservoir, (3) intermediate-term
effects on the reservoir, (4) long-term effect, (5) impact on
the Manatee County water plant, and (6) expected radium-226
levels in the raw and finished water supplies.
Effects on Stream Water Quality - The initial effect of a
hypothetical dam break on either the North Fork or East Fork
would be a temporary stoppage of flow upstream of the break point
(caused by waste clays effectively damning the stream) coupled
with a complete displacement of downstream water by the advancing
front of waste clays. Extremely turbid conditions immediately
following the spill may be expected to render the river
temporarily uninhabitable for all but the most tolerant of
organ i sms .
Review of available U.S.G.S. water quality data in the Peace
River following the Cities Service settling pond embankment
failure (December 3, 1971) indicated that turbidity levels were
generally higher upstream of the spill than downstream. While
the U.S.G.S. sampling events missed the actual peak in turbidity
which was sufficient to cause extensive fish kills in the river,
the data nevertheless indicate that average turbidities were
at background levels within three to four months after the
spi 11.
Based on the available data, the total phosphorus concentration
downstream of the spill appeared to have risen slightly over
background but remained well below the average phosphorus level
upstream of the spill.
Short-term Impact on Reservoir- The short-term impact (i.e.,
within days to weeks following the accident) on the Lake Manatee
99
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Reservoir was estimated by assuming complete and instantaneous
mixing of the 1,000 acre-feet of clear water discharge from the
clay settling area with the minimum 6,920 acre-feet of reservoir
storage.
Estimated concentrations of TSS, TDS, fluoride and total
phosphorus were slightly to moderately greater than background
levels in Lake Manatee; butr in no case did a predicted
concentration exceed the state standard for Class I-A waters.
Intermediate-term Effects of Suspended Solids Loading of Lake
Manatee- As in the case of the Cities Service Peace River spill,
it is anticipated that the elevated total suspended solids
loading in the river (as indicated by turbidity) would persist
for several months, gradually tapering off to the background
levels as the exposed surface clays desiccated and vegetation
re-establishes in the floodplain (Ardaman and Associates, Inc.,
1979). The TSS concentration in the Manatee River was estimated
to increase by 730 mg/1 during the interim period. The
additional sediment load over a two month period could deposit
up to 60 acre-feet in the reservoir, a small amount relative
to the remaining dead storage of 2,000 acre-feet (Ardaman and
Associates, Inc., 1979).
The concentration of suspended solids at the intake structure
to the water plant was estimated using Stoke1s Law (American
Water Works Assocation, 1971) and the known particle size weight
distribution determined from a sample of waste clay from pilot
plant runs with the proposed mine matrix (Ardaman and Associates,
Inc., 1979a). It was conservatively estimated that 93% of the
suspended solid would be removed; hence, a maximum of 52 mg/1
could be expected to enter the lowermost water intake structure.
The above analytical prediction was verified through an
independent, empirical method developed by Brune (1953).
Long-term Effects of Dissolved Constituents- Following the
hypothetical accident, water entrained in clays deposited on
the reservoir bottom and in the riverbed will slowly be expelled
into the water column as the clays consolidate. Potential
increases in concentrations of fluoride, TDS and phosphorus in
the lake were examined. The predicted increase in fluoride level
-0.004 mg/1 over the background level of 0.45 mg/1 - would have
virtually no effect on the quality of the water supply. The
effect of other constituents dissolved in the expelled water
would be equally insignificant due to their substantial dilution
by the relatively large volume of natural flow through the
reservoir and water storage therein.
Effects on Water Treatment Plant Capacity- The intermediate-term
increase in TSS levels in the reservoir will entail both
beneficial and adverse effects with respect to the water plant's
operation. Because of the affinity between suspended inorganic
materials (such as clays) and organic compounds (EPA, 1967)(such
as color) some reduction in the background color levels may be
expected. On the other hand, the higher suspended solids
concentration in the raw water would increase the quantity and
100
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possibly the density of sludge. An increase in alum dosage
necessary to maintain effective coagulation-flocculation could
also be expected. It is likely that the additional cost of
treating an intermediate level of suspended solids (EPA, 1974)
over a two to three month time span would be moderate compared
to the total annual cost of supplying treated water to the system
users.
The present sludge disposal facilities are susceptible to being
overloaded in the event of a sudden increase in sludge loading.
Hence, the increased rate of sludge production resulting from
a hypothetical embankment failure might briefly exceed the
present capacity of the drying beds and lagoon. Disposal of
the small volume of addition sludge produced over a two to three
month period would therefore require some expansion of existing
drying bed and lagooning system.
Effects on Radium-226 in Manatee River and Reservoir- The
evaluation of changes in radioactivity levels in waters affected
by the hypothetical accident focused on radium-226, the most
hazardous of the several radioactive species that are potentially
involved in water contamination (Radiological Environment
Resource Document). Because of the extreme insolubility of
radium-226 in water (Radiological Environment Resource Document),
the potential pathway by which radium-226 might enter the Lake
Manatee reservoir is in association with suspended clay
particles. Based on the maximum expected radium-226
concentration in the waste clay of 8 pCi/g (Radiological
Environment Resource Document) and predicted TSS concentrations
at the head of the reservoir and at the dam of 730 mg/1 and 52
mg/1, respectively, the corresponding suspended solids components
of radium-226 were estimated to be 5.8 and 0.4 pCi/1
respectively. Conservatively taking the background level as
0.8 pCi/1, the total radium-226 concentration at the head of
the reservoir and at the dam for a period of several months
following the hypothetical embankment failure were estimated
to be 6.6 and 1.2 pCi/1, respectively. Hence, the State's radium-
226 standard of 5.0 pCi/1 for Class I-A waters would be slightly
exceeded at the head of the reservoir, but satisfied at the
critical point of water intake to the treatment plant.
Importantly, the treatment process itself could be expected to
further reduce the radioactivity level. As pointed out in the
Radiological Environment Impact Resource Document "any treatment
of waste waters for other water quality parameters has an
inherent high efficiency for radioactive species in the same
wa t e r" .
Biological Effects: Biological effects caused by clay wastes
from the hypothetical spill will be felt in the floodplain of
the Manatee River, in the wetlands associated with the river
upstream from the spill site, and in the Lake Manatee Reservoir.
Based on the effects of spoil placed on hydric swamps along the
Apalachicola River in the Florida panhandle (Clewell and
McAninch, 1977), the effect of the solids on the Manatee River
floodplain would be to kill most trees and severly stress many
101
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of the surviving trees. The effects would be more severe if
the spill occurred in the growing season rather than in the
dormant season.
Following the spill the new substrate would be available for
revegetation. Theoretically, a swamp community resembling the
present natural swamp would develop gradually through plant
succession. Whether or not such development would occur is
speculative because there is no comparable site in the region
which has undergone such perturbation and which has been allowed
to undergo succession without further disturbance for several
decades.
Since much of the land upstream from the site is scheduled for
mining, the effect of ponding is mostly inrmater i al .
The spill would result in the destruction of the aquatic fauna
of the river. Benthic organisms will be buried; other organisms
will suffocate as their gills become clogged by the clays and
silt. Few, if any, organisms will survive. Once the clays have
settled, the river would begin to be recolonized by opportunistic
species able to adapt to the new conditions. Species diversity
would be low initially and increase as vegetation became
re-es tablis hed.
The spill would cause an increase of the water level in the
reservoir by less than two feet. This increase will cause a
minor readjustment of hydric vegetational zonation which will
constitute a negligible impact. The effect of the spill on the
limnetic zone would be a short-term reduction in productivity
while turbid conditions persist.
The greatest impact would be the destruction of the present
littoral zone in the upper end of the reservoir. The rather
extensive vegetation, consisting of submersed and emergent
aquatic plants would be destroyed. A new littoral zone would
be created on the clays which would form the new substrate.
From the angle of deposition, it is likely that the new littoral
zone would be roughly one-third as large in area as the present
littoral zone. The reduction in littoral zone area would reduce
the biologic productivity of the reservoir.
Mitigating Measures
The following water treatment facilities and design features
of the proposed mine will serve to mitigate the potential impact
of mine discharges on receiving waters:
o Wastewaters from ore transportation, washing, flotation,
and waste disposal operations will be recycled to the water
recirculation system for treatment in the clay settling
area, thereby, substantially reducing a potential source
of water polluti on.
o The 480-acre clay settling area will serve as an effective
clarification facility, removing approximately 99.9% of
the suspended clay solids.
102
-------
o Runoff from active mining and reclamation areas, roadways,
and the benefication plant area will be routed to the
recirculat ion system for treatment.
o Domestic sewage generated during the construction phase
of the mine will be treated with chemical toilets. Sewage
generated during the operating phase will be treated in
an on-site extended aeration treatment plant.
The following steps will be taken to prevent the possibility
of a settling area failure and release of waste clay to the
Manatee River:
o The settling area will be designed by an experienced
professional engineer and be based on a thorough
investigation of foundation and soil conditions existing
at the proposed construction site.
o The rules of the Department of Environmental Regulation
for the design, construction, inspection and maintenance
of earthen dams promulgated under chapter 17-9, Florida
Administrative Code will be strictly adhered to and
complied with. The proposed mining operation will also
comply with all other state and/or local ordinances
concerning retaining dikes.
o The construction of the initial settling area will be
inspected daily by a qualified representative of the design
engineer to ascertain that the embankments, spillways,
and control structures meet the design specifications.
Prior to the introduction of waste clay into the area,
the entire structure will be thoroughly inspected by the
design engineer.
o The settling area will be visually inspected each eight-
hour shift and will be thoroughly inspected on a weekly
basis by operations personnel, who have been instructed
by the design engineer, regarding items to be checked.
o A registered professional engineer, who is experienced
in the design, construction, and maintenance of earthen
dams will make annual inspections of the dam systems.
He will also review on a monthly basis the reports of the
operation personnel. A report of his findings will be
submitted to the Florida Department of Environmental
Regulat i on.
4.11 RADIOLOGICAL ENVIRONMENT
Baseli ne
The following will attempt to describe the background condition
of the natural radiation environment in the absence of the
proposed mining facilities. Specific items to be covered include
the uranium series (particulari1y radium-226 and radon-222),
radon progeny, terrestrial garrma radiation, airborne
103
-------
radioactivity, subsurface profiles of radioactivity, radium-226
in surface waters, and radium-226 in ground waters.
Primary apatite, the most common mineral of the phosphate
group, contains only trace amounts of uranium, generally
on the order of a few thousandths or hundredths of one
percent or about four orders of magnitude higher than most
other natural materials. Thus, apatite serves as a natural
concentrator of uranium. When submitted to extensive marine
reworking, the uranium content of sedimentary apatites may
be increased to as much as 0.1%.
The uranium content of the phosphate matrix of west central
Florida may average 120 ppm. Individual samples of selected
strata may exceed 400 ppm U. The radiological hazard of
the uranium ore is associated with individual isotopes and
the decay products. The specific activity of U-238 is
0.33x10 pCi/g.
The Primary Drinking Water Regulation - Radioactivity
published by EPA in July 1976 limits the total radium in
water to 5 pCi/1. Both radium-226 and radium-228 can
contribute to this 5 pCi/1 limit. Radium-228 is the first
daughter of the naturally occurring thorium-232 series.
In general, the world average concentration of thorium in
various igneous rocks, limestones, and sedimentary rocks
is about three times that of uranium (ppm basis). However,
since thorium-232 has a specific activity, about one-third
that of uranium-238, the radioactivity of the two
radionuclides in many soils and rocks is more nearly 1:1
(pCi/g basis). Specific data on thorium-232 in Florida
phosphate associated media indicate the U/Th ratio in terms
of pCi/g per pCi/g to be about 100. Thus, radium-228 in
west central Florida will be undetectable in most media.
In the uranium-238 series, decay proceeds serially through
13 intermediate radionuclides, called daughters, to a stable
endpoint of the element lead with a mass number of 206.
A condition of equilibrium is achieved if the entire series
is contained in a "sealed" location over a long period of
time. In other words, a geological sample containing 100
pCi of U-238 may also contain 100 pCi of Th-234, 100 pCi
of Pa-234, 100 pCi of U-234, and so on, through 100 pCi of
Po-210. Equilibrium is maintained only if the materials
are und i s t ur bed.
Radium-226 is of particular interest in regard to human
exposure. Radium is chemically similar to calcium and
replacement is clearly demonstrated by the high radium-226
concentrations found in the gypsum. Radium, like uranium, is
ubiquitous in nature and is found in almost every environmental
medi a.
The radium-226 decay scheme equilibrium is highly dependent
upon the mobility of the radon-222, an inert gas. The four
radionuclide daughters of radon-222 are known as radon
progeny (or daughters of radon). In the natural unmined
104
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state, most of the radon-222 produced in a phosphate matrix
would not escape the media. Mining and beneficiation alters
the probability that radon-222 will be able to diffuse from
the site at which it was created.
Subsurface Radioactivity - Since the origin of the uranium
in the deposits is similar to the phosphate, it should be
evident that the concentration of uranium and thus radium-226
should follow the concentrations of phosphate: a low
concentration in the overburden and a high concentration
in the matrix. The actual distribution is slightly
different.
In the west central Florida mining regions, the radioactivity
is low at the surface, increases gradually, and then more rapidly
with depth and is most concentrated in or just above the matrix.
The profiles indicate a wide variation with small distances
within the matrix. Figure 4.11-1 shows the distribution of
radium-226 samples versus depth for core samples at the Duette
site. All uranium concentrations (pCi/g) were approximately
equal to those of the radium-226. The radium-226 concentration
in Duette site top soil averages 0.5 pCi/g or about same as the
west central Florida top soil.
0.0
2.0 4.0
Radium-226, pCi/g
6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
20.0 •
40.0
60.0
80.0 •
• ' 1 1 1 — < 1 1 111)11
t \
t. xx
1 + -%
u+ + V_
1
• 1 + ~~--
'" * '
\ *
~- +
•^
-^ . +
-- t
/
/
/ _,
/
/
/ -*
/ *
\ "*" -V
1
1
I
v^
X
•N
^ 4-
X,
V
\
*x
^ +
-\
1 1 1 1 1 1 -T — T 1
-T- ^^
^~>N
*
T\
Approximate
Top Of x
Matrix \
-i- \
/
*
/
/
/
/
/
/
/ T
/ Approximate
' Bottom
/ Of Matrix
•'' 1
Figure 4.11-1 Profile of Radioactivity at the Duette Site
105
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The overburden radium-226 data for the Duette site when
compared to the west central Florida data of Roessler et.al.
(1978) indicates that the Duette site has about 40% less
radioactivity. Both the averages and upper ranges of individual
samples indicate a matrix concentration of radium-226 at the
Duette site that is much lower than the 26 pCi/g matrix of the
west central Florida mining district.
Since a major fraction of the gamma radiation level in
Florida is related to the uranium series, gamma logs of wells
should also reflect the radium-226 profile shown in Figure
4.11-1. The gamma well log from the Duette site is shown
in Figure 4.11-2. The garrma activity in Figure 4.11-2 (also
relative radium concentration) increases nearly linearly with
depth to approximately 35 feet where the rate sharply increases
as does the phosphate level and then falls gradually to around
the 100-foot mark. The mineable matrix at this core lies between
the 35-foot and the 90-foot levels. Since the origin of the
matrix is known to be linked to the Hawthorn Formation, the
entire Hawthorn strata, here approximately 300 feet thick, would
be expected to also contain uranium and its daughters because
of its geologic history. The garrma log dramatically illustrates
th i s fact.
By the method of graphical integration it is readily apparent
that the combination of both the overburden and the mineable
matrix represents only 8.1% of the total activity in the 1000-
foot column. The remaining Hawthorn Formation from which the
matrix was derived, represents about 50% of the total
radioactivity within the 1000-foot column. The relationship of
the deep aquifer radium and the high radioactivity in the total
Hawthorn is not understood, however, current levels of radium
in the aquifer may be more closely related to the lower Hawthorn
than the matrix some 300 feet above.
Terrestrial Garrma Radiation - Table 4.11-A summarizes the
estimated average background doses to United States citizens
from natural radiations and compares it to estimates from
other man-made sources. The total annual dose to an average
United States citizen is about 182 mrem/yr. The largest
fraction (58%) is contributed by environmental sources.
The fraction of the environmental radiation dose of interest
here is the external terrestrial radiation. This catagory
can be enhanced by the technological activities of man, such
as the mining and processing of ores.
106
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SURFACE
OVERBURDEN
2
LLJ
O
cc
01
Q.
3
O
01
>
oc
O
oc
01
O
z
01
OC
Ol
O
oc
FIGURE : 4.11-2
GAMMA - RAY LOG OF A
DEEP WELL ON THE
DUETTE SITE
SOURCE . DR. E. BOLCH
P.E.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
Table 4.11-A Average Doses from Radiation in the United
States in 1970
Source mrem/year* Source mrem/year*
Environmental Medical
Natural Diagnostic 72
Cosmic Rays 44 Radiopharma-
Terrestrial Radiation ceuticals 1
External 40
Internal 18 Miscellaneous 3
Global Fallout 4
Nuclear Power 0.003 Grand Total 182
*Field measurements are usually made in units of yR/hr.
For X- and gamma radiation 1 yR/hr - 1 mrem/hr - 8.8
mrem/yr.
In the continental United States, the external background
terrestrial radiation arises primarily from garrma ray
emissions of the thorium series, the uranium series and
potassium-40; however, in Florida the contribution by the
uranium series accounts for a high percentage. The overall
average level in Florida (41 to 55 mrem/yr) is lower than
the national average of 84 mrem/yr.
A radiological survey of the terrestrial garrma levels on
the site reveal that the average total external gamma level
for the entire property (over 200 measurements) is
approximately 5.1yR/hr, which can be converted to an annual
exposure of 45 mrem. Altered lands in west central Florida
have elevated garrma radiation levels: sand tailings - 11
yR/hr, overburden reclaimed land - 13yR/hr, clay reclaimed
lands - 17yR/hr and debris lands - 22yR/hr.
Airborne Radioactivity - Airborne radioactivity over
una1tered 1ands ar i ses from two major sources. Particulates
containing the naturally occurring radioactive materials
such as the uranium series become airborne as "dust". The
second source is the diffusion of the gas radon-222 out of
the soil surface.
In general, national ambient levels of gross beta activity
in particulates range between 0.1 and 1.0 pCi/m . Gross
alpha measurements average one to two orders of magnitude
less. Partridge et.al. (1977) reported a sunrmary of an
ambient air sampling network for nonphosphate areas of Polk
County. The data are compatible with the national ambient
levels given above.
Radon-222 is a natural constituent of all air, but its
concentration may vary over a wide range depending on the
radium content of the upper layers of the earth and the
prevailing meteorological conditions. Radon-222 content
of ambient air at several locations in Florida ranges from
0.02 pCi/1 in the afternoon to 0.3 pCi/1 in the morning hours
(Williams et.al. 1965).
108
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Because of the wide variation in hourly measurements of radon-
222 in air due to atmospheric conditions, radon-222 flux
measurements from the soil surface have been determined to
be a valuable indicator of potential environmental impact.
The radon flux baseline level (unaltered lands) in west
central Florida is about 0.2 pCi /m s and elevated levels
over various types of phosphate related lands are observed:
sand tailing - 0.7 pCi/m s, overburden reclaimed lands -
1.5 pCi/m s, clay2reclaimed lands 1.6 pCi/m s, and debris
lands - 4.2 pCi/m s.
Water Quali ty - Two water regimes will be considered with
respect to radiological quality; surface waters and ground
waters.
Radium-226 in surface waters of the USA is generally low
(between 0.03 and 1.0 pCi/1). This same range is reflected
in the measurments reported for Florida surface waters.
Table 4.11-B contains a surrmary of surface water radium-226
concentrations for the site and two downstream stations.
The dissolved radium values were less than 0.8 pCi/1 for
four out of the six of the on-site samples.
Table 4.11-B Sumnary of Surface Water Radium-226 Concentration
On Site and Off Site.
Description Und
East Fork, Manatee River Entrance
East Fork, Manatee River Exit
North Park, Manatee River
Creek Crossing Rt . 39 West Side 1.
Small Stream, Middle of Track
North Fork, Manatee River Exit 0.
Manatee River at Lake Manatee
Manatee River at Bridge, S.R. 64
Unreclaimed Lake-31 sample, 61 deep
Unreclaimed Lake, Surface Sample
Unreclaimed Lake-12' deep
Old Colony Mine Pit, Surface Sample
Old Col ony Mi ne Pi t , 12' Sample
Old Colony Mine Pit, 24' Sample 1.
Settling Area, Agrico
Radium-226,
i sso 1 ved
<0.8
<0.8
<0.8
1 + 1.1
<0.8
8 + 0.8
<0.8
<0.8
<0.8
<0.8
<0.8
<0.8
<0.8
6 + 1.2
<0.8
pCi/1
Di ssol ved
<0.8
1.8 + 1. 1
<0.8
<0.8
<0.8
2.4 + 1.0
<0.8
<0.8
<0.8
<0.8
3.0 + 1. 1
1.2 + 1.1
<0.8
1.2 + 1.2
<0.8
The water management program will determine radiological
contamination during the mining phase, whereas the
reclamation plan with its on-site drainage system and
preventative measures against turbid runoff will determine
the long term impact. It is important to recognize that
radium is highly insoluble in comparison to other water
quality parameters and measures to control other non-
radioactive contaminates is normally sufficient to limit
the impact of radium-226.
109
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A review of the literature and analysis of radium-226 in
groundwaters of west central Florida is presented by Kaufmann
and Bliss (1977). They statistically analyzed available
radium data from 1966 and from 1973-1976 in three strata:
upper water table, Upper Floridan aquifer, and Lower Floridan
aquifer. Each water resource was considered in three
geographic areas of west central Florida: mined mineralized
areas, unmined mineralized areas, and non-mineralized areas.
The basic data summary is shown in Table 4.11-C.
Table 4. 11-C
Summary Of Radium-226 Data In Central
Floridan Aquifers
Aqui f er
Area Water Table Upper Floridan Lower Floridan
Descr i pt i on
Unmi ned
Mi ner a 1 i zed
Mi ned
Mi nera 1 i zed
Non-mi neral ized
(Control )
No.
23
12
NO
pCi/1*
0. 17
0.55
DATA
No.
5
10
3
pCi/1
2.30
1.6
5. 1
No. pCi/1
2k 2.0
16 1.96
14 1.4
Source: After Kaufmann and Bliss, 1977
* All data are geometric means of author's preferred data.
The mined area appears to have a higher radium-226 in the
water table aquifer, but statistical tests indicate no
s i gn i f i cant
difference between the 0.17 and 0.55 pCi/1.
When the Upper and Lower Floridan aquifer data were
considered, mined areas and non-mined areas were all
approximately equal. The comparison of non-mineralized data
versus the mining areas showed that the Floridan had higher
concentrations of radium-226 in the non-mineralized areas.
The Floridan aquifer showed significantly higher levels than
the water table aquifer.
Kaufmann and Bliss did not consider garrma logs of deep
wells. Garrma logs to 1,000 feet show considerable
radioactivity in the Hawthorn Formation overlaying the
Floridan Aquifer. The garrma logs strongly suggest that the
lower Hawthorn may itself be a source of radium-226 in the
Floridan Aquifer. The literature values for radium
concentrations in ground waters appear to follow the same
pattern with depth as the deep garrma logs.
Because radium-226 is found in all subsurface strata at
various concentrations including some that are much higher
than the mined matrix, the identification of ground-water
contamination beyond natural causes and the determination
of its source is an exceedingly complex problem.
Surrmar y
foilows
- Baseline conditions at the proposed site are as
Subsurface Radioactivity - Uranium and radium-226
110
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measurements confirm high activities either just
above or in top of the matrix. Overburden has
concentrations of radioactivity typical of west
central Florida, however, the Duette matrix is deeper
than in most current mines. Uranium and radium-226
continues throughout the matrix and into the Hawthorn
and exceed the matrix concentrations.
Garrma logs show high levels at the top of the matrix,
some continued higher radioactivity through the
Hawthorn with a decrease within the Floridan
Aquifer .
The U/Th ratio in subsurface strata is much greater
than the national average. Thus, radium-228 is not
considered a potential contaminant.
Matrix Radioactivity - Radium-226 is approximately
5 to 8 pCi/g or less than one-third of that observed
at currently operated mines in west central Florida.
Ganma Radiation - The external ganrma radiation is
approximately 5.1 R/hr over unaltered 1ands on the
site. Typical Florida background radiation ranges
f rom 4.7 to 6.3 R/hr.
Airborne Radioactivity - The agricultural nature of
land indicates low airborne particulate activity:
less than 0.01 pCi/m3 gross beta, and less than 0.001
pCi/g for specific long lived radionuclides such
as Uranium-238, Thorium-230, Radium-226, etc.
Ambient levels of radon-222 are expected to be less
than 0.1 pCi/1.
The surface flux of radon-222 on |he unaltered site
is expected to not exceed 1 pCi/m s.
Surface Water Radioactivity - Radium-226 levels are
between less than 0.8 to 2.4 and normally less than
1 pCi/1. These values are higher than the national
average, but comparable to other surface water in
unmi ned areas of Florida; Uranium and Radium-228
concentrations in surface waters are below normal
detection limits.
Ground Water - Radium-226 levels are between less than
0.8 and 6 and normally less than 3 pCi/1 in important
aquifers. Concentration appears to be related to
depth and, therefore, to radium in the immediate
media. Poor water quality, especially Na+ (or C1-),
may enhance radium content.
Impact
The proposed Duette mine may alter these baseline conditions.
This section will: 1) describe the redistribution of the
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radioactivity and radiation, 2) propose potential contamination
and exposure pathways, 3) predict or estimate the effects on man
or the environment, 4) provide a comparative measure and
perspective, and 5) substantiate the basis for any mitigative
rneas ures .
In the mining process, overburden must first
to gain access to the matrix. Core analyses
radium-226 profile in
than 1 pCi/g near the
at the matrix interface.
be s t r i pped
have shown the
the site overburden to range from less
surface to a high of about 18 pCi/g
The matrix must be removed and slurried to a
washer/beneficiation plant. The complete process and
distribution of radioactivity for current practice (Roessler
et al., 1978) is compared to the Duette site in Figure 4.11-
3. The west central Florida clays average about 4.5 pCi/g
for radium-226. By pilot plant studies with the matrix,
the clays at the proposed site range from 3.2 to 5.6 pCi/g
radium-226. The radium-226 in pebble from the site is
approximately one-half of the average in the west central
Florida plants. The west central Florida tailings now
average about 5 pCi/g, while Duette pilot plant tailings
have a radium-226 concentration of 1 pCi/g.
waste material
Overburden Spoil Piles
Current Mines: 0.5 - 7
Current Mines
T5 (26 - 50)
24 (21 ^
Sand Tailings
Current Mines
5.2 (1.7 - 12)
Duette
1 (0.8 - 1.4)
Figure 4.11-3 Comparison of Radium in Current Central Florida
Products and Wastes to Expected Values at the
Duette Site
A potential direct impact of mining and beneficiation is
that of occupational radiation exposures at either the
dragline area or beneficiation plant. However, Prince (1977)
surveyed six west central Florida plants and found
radiological impacts to operating personnel at mining and
beneficiation processes were minimal.
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Potential occupational exposure hazards to be considered
at drying, storage, and shipping operations are garrma
radiation doses, exposure to radon progeny, and inhalation
of long-lived radionuclides. Exposure locations include
storage areas, loading tunnels, dryer buildings and rock
1oadi ng areas.
Prince (1977) has studied the occupational radiation
exposures in these phases of the industry. Wet rock storage
piles yielded the highest average gamma radiation level of
67pR/hr. However, extremely small occupancy times made
individual annual exposures insignificant.
Prince's results for airborne radon progeny hazards indicated
the rock pile transfer tunnels, especially when unventi1ated,
to be the most serious hazard. The Duette operation, having
both a lower radioactivity concentration in the stored
material and properly ventilated tunnels, should not
experience adverse occupational exposures.
The existing profiles of radioactivity with depth will be
altered by the mining and subsequent reclamation. The radium-
226 (and uranium-238) concentration in the post-mining
overburden can be estimated to be 1.5 pCi/g. Any stored
topsoil to be replaced should have a lower radioactivity
(xO.5 pCi/g). The two waste products, sand and clay, when
combined at a proposed 2.5:1 ratio will have a final radium-226
concentration of 1.9 pCi/g.
The reclamation plan calls for 80% of the reclamation to
be with this sand clay mixture. Another 13% will be by
covering sand tailings with two feet of overburden. The
remaining 7% of the reclaimed land will be the final clay
set t i ng area.
Alteration of Terrestrial Garrma Radiation - The redistributed
radioactivity in reclaimed lands will alter the terrestrial
garrma radiation. Table 4.11-D illustrates the elevation
of garrma radiation as a result of current mining. However,
the lower radioactivity at the Duette site will not
experience the degree of elevation of garrma radiation that
has occurred over various land types in Polk County.
The predicted impact has been estimated by consideration
of the expected uranium, thorium, and potassium contents
of various post reclamation land types and the equations
of Beck and de Planque (1968). No credit was taken for any
low activity topsoil or its shielding properties. The
predicted total external garrma radiation levels were 7.1
yR/hr for overburden reclaimed, 8.7yR/hr for the sand/clay
mixture, 5.9yR/hr for tailings reclaimed, 13.8pR/hr for clay
reclaimed and a weighted average for the site of 8.8yR/hr.
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Table 4.11-D Garrma Radiation Levels of Various Land Types
in Fl or i da
— NQ^ £-£Garrma Level, yR/hr~~
Coun_t_y_ & Land Type Sites Geom. Mean Range
Polk Co.
Unaltered 9 5 *-7
Unmined Radioactive
Fill 1 9 -
Sand Tailings 11 H 6~16
Al 1 Overburden
Reclaimed 16 13 7-33
Capped and Mixed
Clays 6 17 11-2*
Debris 8 22 11-5*
Alachua Co.
Unaltered 6 6 5-8
after Roessler, et. al. 1978
Airborne Radioactivity - Fugitive dust control has been
adequately addressed in other sections. The impact of the
dryer emissions, however, requires further consideration.
Offsite transport of the radioactivity and subsequent
potential radiation doses to the general public can be
estimated by the use of EPA computer code: AIREM (Martin,
et al. 197*). AIREM is a computer code for the calculation of
doses to the general population due to atmospheric emissions of
radionuclides. The input data and requirements for AIREM
calculations are presented in the Radiological Environment
Resource Document. Ten segments at radii of 100 meters to 10
miles were used.
Dryer Emissions: The two rock dryers proposed for the
facility will utilize cyclone particulate collectors and
wet scrubber collection devices. The scrubber exhausts will
discharge through stacks.
Dry deposition at the nearest offsite location to the north
of the plant would add approximately 30 pCi/m per year of
radium-226 to the soil. Since topsoil has about 0.5 pCi/g
and a density of about 1.* g/cc, the |irst centimeter of
soil will normally contain 7000 pCi/m .
Lung dose calculations indicated an offsite dose for
continuous exposure of 0.* mrem/yr one mile north and at
Keentown some 2 miles NNW of the plant the predicted lung
dose rate is 0.15 mrem/yr. Neither annual dose at these
offsite locations can be measured within the statistical
variation of natural background.
Radon Flux from Reel aimed Lands: Radon-222 flux from the
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soil surface will be increased due to the redistribution
of radiurn-226 in the reclaimed lands. Radon in the
atmosphere will experience some elevated concentration due
to this increased surface flux.
The predicted radon flux values for various land types of
the post-reclamation ghase is as follows: overburden 2
reclaimed -0.75 pCi/m s, sand/clay mixture - 0.84 pCi/m s, 2
tailing reclaimed - 0.46 pCi/m s, clay sediments -21.04 pCi/m s
and the weighted average for the site - 0.80 pCi/m s. Any
topsoil of lower activity added to any of these land types will
reduce these flux values. The elevation of outdoor airborne
radon-226 from these fluxes will not be significant.
Reclaimed Land Use - The reclaimed lands will have different
radiological characteristics than the land before mining.
Two radiation exposure pathways appear to be most directly
related to reclamation and land use: 1) working level (WL)
elevation in residential structures; and 2) uptake of
radionuclides into agricultural products.
The impact of residential development must be considered,
whether for small numbers of homes in the in-mediate future
or significant numbers in the future.
Certain land parameters have been shown to predict indoor radon
progeny in s1ab-on-grade constructed homes in west central
Florida (Roessler et al. 1978). The predicted indoor radon
progeny levels by land type for the Duette site after reclamation
are as follows: overburden reclaimed -0.008 WL, sand/clay
reclaimed - 0.009 WL, tailings reclaimed - 0.006 WL, clay
sediments - 0.015 WL and the weighted average for the site -
0.009 WL. No credit was given for topsoil replacement in the
calculat i ons.
If the final guidance (EPA, 1979) for reclaimed lands
suggests an upper limit of predicted radon progeny in
siab-on-grade homes of 0.009 WL (normal background of 0.004
WL plus the uncertainty of 0.005 WL) then the Duette site
may have to consider the return of topsoil to any residential
development site. If clay settling areas are excluded for
structural reasons, then no reclaimed Duette site lands are
predicted to produce homes with radon progeny levels near
the 0.02 WL remedial action level (EPA, 1979).
Some 68% of the land is expected to be improved pasture and
a very small percentage (less than 5%) may be used for citrus
and row crops. The scientific literature contains little
information on the potential for crop uptake of radiurn-226.
Most literature data suffers from the lack of companion
information on other nutrients in the soil and in the crops.
The return of any low activity topsoil to reclaimed areas
will substantially reduce any potential impact. The most
important pathway to consider is the direct uptake by row
crops grown on the reclaimed clay. Here the radium-226
content is the highest and land will be suited for this
115
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productive use. Little is known about the behavior of radium-
226 uptake from this type of soil. A very limited study
suggest that the excess availability of the major divalent
cations (Ca++ and Mg++ primarily) produce a discrimination
against uptake of Ra++ in the clay soils containing higher
than normal radiurn-226.
Since current fertilizer products such as TSP may contain
up to 32 pCi/g radiurn-226, the direct application of
fertilizer products to crops may be much more important than
direct uptake from the reclaimed soil being farmed.
Product Radioactivity - The offsite shipment will be 62 million
tons of phosphate rock at 21 and 31 pCi/g of radium-226 and
uranium. The secondary impacts of these materials will depend
upon the location of any additional processing, the final product
and i ts end use.
Water Quali ty - Radioactivity represents one of many water
quality parameters. Ground water and surface waters
represent the two major pathways of transport to man and
each will be discussed separately.
The important guideline for radioactivity in drinking water
is that the combined radium-226 and radium-228 shall not
exceed .5 pCi/1. The EPA has established an effluent
guideline for the phosphate industry of 9 pCi/1 of radium-
226.
Surface Water Quality: A review of the various studies
related to the current phosphate mining indicate that three
factors appear to mitigate the impact of radioactivity upon
surface waters of the phosphate district: a) The critical nature
of water resources encourages a high degree of recycle of water
within the process systems, b) The important radioactive species,
like radium-226, are extremely insoluble under many environmental
conditions, and c) Any treatment of waste-waters for other water
quality parameters has an inherent high efficiency for
radioactive species in the same water.
Mills et al., (1977) have reviewed the beneficiation process
with respect to radioactivity in water. Adjusting their
findings and conclusions to the radioactivity of the Duette
site, the concentration of radium-226 in the discharge from
the clay settling area is expected to be normally <1 pCi/1.
The beneficiation process itself is an extreme opportunity
for leaching and should lead to fractionation of the radium-
226 from the minerals if radium-226 were not so insoluble.
Surface water contamination in runoff from reclaimed areas
is predicted to yield an equilibrium concentration of radium-
226 in contacted water of no greater than 0.2 to 2 pCi/1.
These values would tend to be further diluted by runoff from
areas having less radium-226 in the soil and by waters from
ot her sources.
Ground-water Quality: An analysis of the areawide impact
statement and other site specific DRI's and EIS's indicate that
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radioactivity is not normally the critical water quality
criteria. Some of the same conclusions stated for radioactivity
in surface water (recycle uses, species insolubility, and high
removal efficiencies) are just as valid for reducing the
potential for ground-water contamination.
The areawide impact statement for the industry (EPA, 1978)
recommended that recharge water from the connector wells
should meet recommended drinking water criteria chemically,
bacteriologically, and radiological1y at all times. The
radioactivity levels in the shallow aquifer water at the
Duette site should be acceptable for recharge to the Floridan
aqu i f er.
It is important to re-emphasize that any existing radium-226
in ground waters, especially in the Floridan aquifer, may
have a variety of sources and the most likely source is the
naturally occurring radium-226 in the lower Hawthorn. This
fact also makes it exceedingly difficult to "trace" radium-
226 to its source, since nearly all materials and strata
contain measureable quantities.
Surrmary - The radiological impact of the proposed Duette
mine, its beneficiation process and other activities are
as foilows:
Matrix Radioactivity - Radium-226 (9 pCi/g) in the matrix,
some forty feet below the surface, will be mined and
partitioned into waste clays (4 pCi/g), sand tailings
(1 pCi/g), product pebble (29 pCi/g) and product
concentration (24 pCi/g).
Subsurface Radioactivity - Pre-mining radium-226 profiles
(<1 pCi/g at the surface to 18 pCi/g near the matrix)
will be altered to a reclaimed profile having from
between 1 and 4 pCi/g nearly uniformly distributed with
depth.
Occupational Exposures - The highest potential for
occupation exposure would be in loading tunnels unless
they are ventilated and occupancy times restricted.
Terrestrial Gamma Radiation - The mean outdoor gamma
radiation of the site is expected to increase from 5.1
vR/hr to 8.8 yR/hr.
Airborne Radioactivity - Dryer and other airborne
emissions are expected to deposit over half of the
radioactivity within a radios of 7.5 miles.
The yearly depositon (pCi/m per year) beyond one mile
would not increase the radioactivity of the soil to any
measurable degree.
Lung dose calculations indicate the highest dose rate
for continuous exposure to be 6 mrem/yr at 500 meters
west of the stack. All lung dose rates for continuous
exposure beyond 1.5 miles are less than 1 mrem/yr.
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Radon flux from the soil surfaces of the site are2
expected to increase from a baseline of 0.2 pCi/m s to
less than 0.8 pCi/m s.
Elevation of outdoor airborne radon-226 is not expected
to be measurable.
Land Use Criteria - Residential development for the site
is not expected within the in-mediate future. For any
homes that are constructed, the predicted indoor radon
progeny (WL) could range from .005 WL (tailings
reclaimed) to 0.023 WL (clay settling areas).
Agricultural development of the site is not predicted
to pose any radiological impact from the limited soil-to-
crop-to man food chain uptake.
Surface Water Radioactivity - Surface water radium-226
concentrations in off-site environs may be elevated from
natural levels of 0.8 pCi/1 to 2 pCi/1. By
comparison, the drinking water standard for radium-226
is 5 pCi/1 and the discharge guideline for the industry
is 9 pCi/1.
Ground-water Radioactivity - The ground-water radium-226
concentratons at the site are less than those observed
in non-mining regions. Radium-226 in ground waters
appears to be associated with local subsurface
envi ronment s.
The connector wells for recharge of the Floridan aquifer
represent a potential transport mechanism for
radioactivity. However, monitoring of the more basic
water quality parameters should prevent contamination
by radioactivity.
Mitigating Measures
Mining, Beneficiation, Storage, and Shipping - Specific
rnitigative measures are not indicated for these processes.
The lower radioactivity of the matrix and subsequent products
reduces the concern for any occupational exposure, although
ventilation of transfer tunnels and limited occupancy is
benef i ci a 1.
Drying and Airborne Emissions - Detailed computer analysis
of radioactivity emissions and dispersion from the dryer
facilities indicate no species controls because of
radiological hazards. Reviews of the literature and other
environmental assessments indicate that adequate control
of other air quality criteria, such as particulate standards,
mitigates the radiological emissions to acceptable levels.
Reclamation - The proposed reclamation plans combined with
the deeper, lower activity overburden and the smaller level
of radioactivity in the primary waste products (sand and
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clay) appear to satisfactorily mitigate most of the post-
reclamation radiological conditions to acceptable levels.
The sand-clay mix reclamation has acceptable radiological
characteristics with respect to 1) alteration of terrestrial
gamma radiation, 2) changes in radon-222 flux from the soil
surface, 3) airborne radon-222, 4) postulated radon progeny
in any residential homes, 5) agricultural uses or 6) return
to natural systems.
All post reclamation criteria for the radiological
environment were estimated without returned topsoil. The
mining plans, however, suggests that approximately 2 feet
of topsoil may be returned to some of the reclaimed areas.
This procedure is recormnended, since expected guidance for
construction of residential homes may require near background
levels. The final clay settling area when returned to any
land use will be most beneficially affected by returned
topsoil. The 3-4 feet of returned topsoil recommended in
the EPA Areawide EIS may have a high cost-benefit ratio in
this region of lower matrix radioactivity.
Surface Water Quality - No specific mitigative measures are
recommended for the radiological quality of waters released
during the operational phase other than meeting the 9 pCi/1
effluent guideline. Water quality data of other
investigations indicate that non-radiological parameters
are the critical discharge criteria. The extremely high
insolubility of radium results in its high efficiency of
removal when treatments are applied to maintain the chemical
aspects of discharge permits.
Calculations indicate that post-reelamation runoff would
not produce radium-226 levels in surface waters significantly
higher than background levels.
Ground Water Quality - The connector wells for drainage
appear to be the critical aspect of potential ground-water
contamination. However, all data indicate that the levels
of radium-226 in the drainage water are lower than the deeper
aquifers. Here again there is the high probability that
another chemical parameter will be the critical agent
necessary to monitor in order to insure that the drained
water meets drinking water criteria. Radium-226 is not
expected to exceed the 5 pCi/1.
Conclus ions - In general, no mitigative measures specific
to radiation appear to be necessary. This is, however,
pedicted upon the various mitigative measures designed into
the non-radiological aspects of the mine operation and
detailed in specific sections of this EIS.
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it. 12 BIOLOGY AND ECOLOGY
Baseli ne
The biological and ecological characteristics of the property
are presented under three major headings based on vegetation
as soci at i ons:
o Land - description of terrestrial plant and animal
conrmun i t i es
o Land/Water Interface - description of plant and animal
cormnunities inhabiting swamps and marshes
o Water - description of aquatic plant and animal
conrmun i t i es
Studies revealed four land connmuni t i es, three land-water
interface cormnunities, and three stream corrmun i t i es . All
communities showed some modifications from logging, cattle
grazing, and/or decreased frequency of fire.
The system of community classification used is adapted from the
classification of forest cover types by the Society of American
Foresters (1954), the classification of wetland vegetation by
the U.S. Fish <5c Wildlife Service (Shaw & Fredine, 1956), and
the classification of cover types in Florida by the Division
of State Planning (1976). Figure 4.12-1 maps existing vegetation
connmuni t i es .
Land - The existing land communities are sand pine scrub,
longleaf pine-xeric oak, xeric oak, and longleaf pine flatwoods.
Sand Pine Scrub: Two stands of sand pine scrub comprise 73
acres. Typical species include sand pine, rosemary, staggerbush,
chapman oak, sand-live oak, myrtle oak, and tallow wood.
Scattered plants typical of the longleaf pine-xeric oak conrnunity
are also present, including longleaf pine and wiregrass. The
earlier literature on the sand pine scrub community stated that
these two communities were distinct. Later authors noted that
the species of the sand pine scrub community have invaded
adjacent stands of longleaf pine-xeric oak after the exclusion
of fire for an extended period (Nash, 1895; Harper, 1915, 1921-
Mulvania, 1931; Kurz, 1942; Laessle, 1967). It is presumed that
the sand pine scrub community of the Swift property has expanded
somewhat into adjacent areas of longleaf pine-xeric oak.
The sand pine scrub community occurs on well drained, sterile
sands and is characterized by an overstory of sand pines and
a dense or at least thickety type undergrowth of shrubs with
coriaceous, evergreen leaves. Species richness is low,
particularly in relation to adjacent longleaf pinelands, and
grasses and forbs are sparse.
The sand pine scrub is less productive in terms of animal life
than other communities of the property. Faunal food resources
are limited largely to acorns, pine seeds, fruits of the tallow
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:34
ROW CROPS
XER1C OAK
STREAMS
CYPRESS
ORANGE GROVES
13 *•* PLATWOOOS
LONG LEAP PME - XERIC OAK
FRESHWATER MARSH
FIGURE ! 4.12-1
VEGETATION
SOURCE : CONSERVATION CONSULTANTS , INC.
U.S. EPA - REGION IV
DRAFT CNVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY , FLORIDA
-------
wood, insects, and twigs. The undergrowth provides some shelter
to non-avian animals (Poppleton et.al., 1972).
Animals seen in the scrub were gopher tortoise, six-line race
runner, armadillo, ground dove, blue jay, and cattle esret.
Several areas had been rooted by feral hogs. The burrows of
gopher tortoises are known to provide shelter for other animals
which would otherwise be unable to survive the arid habitat of
the scrub (Ernst and Barbour, 1972; Hartman, 1976). There is
probably little interaction of consequence between the animals
of the scrub and those of other habitats. The only animal
directly utilized by man in the scrub is the feral hog.
Longleaf Pine-Xeric Oak: This conrmunity is represented by one
small 35 acre stand. The overstory consists solely of longleaf
pine with a canopy closure of about 50-75%. The understorv
consists primarily of turkey oak and sand-live oak. The
undergrowth is primarily of wi regrass and other herbaceous
species including golden-asters, deer ' s- tongue, gopher apple,
polygonella, and wing-stem. The species seen were the same as
those in the xeric oak community.
This community was once widespread in peninsular Florida, but
because of clear cutting of the pine, much of it has been
converted into xeric oak community. Pines have not become
restocked mainly for lack of a seed source. Even with the
availability of seed trees, restocking is retarded because of
!II^ f,Sr g',uh5 recJuirement °f a fire irrmediately preceeding
seedfall for seedbed preparation, and the infrequency of
tavorable moisture conditions (Wahlenberg, 1946).
The fauna is treated under the Xeric Oak section as the
communities are essentially the same f auni st i cal 1 y.
Xeric Oak: This community occupies a total of 518 acres and
is dominated by sand-live oak and/or turkey oak. These small
shrubby oaks have a canopy closure of about 50%. Other woody
growth includes saw-palmetto, fetterbush, staggerbush, Chapman
oak, tallow wood, and scrub palmetto. Wiregrass and many other
herbs form the rather dense ground cover. Longleaf pine stumps
were common throughout, which is proof that th! xer i ? SaV P
community was derived secondarily by the removal of these pines
thltting't ™e t?*undancc °f saw-palmetto and fetterbush
Jine fPla?wo°odStMS —^^^ »™ been cutover
Animals seen were gopher tortoise, scrub jay, blue jay, ground
dove, mourning dove, rufous-sided towhee, and armadillo. The
corrrnunity does not have diverse fauna. Perhaps the uniformity
1SCk °f 5°Ver f°r birds and lar§er mammT s"
Pauci*y of the fauna. Animals that would be
exoec
n K §. c
s-d *- -
122
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habits and should occur in areas with larger sand-live oaks (Rand
and Host, 1942; Lowery, 1974).
Several species found in the xeric oak scrub, such as the old
field mouse, gopher tortoise, and doves breed both in the xeric
oak as well as their habitats. However, scrub jays nest in xeric
oak and sand pine scrub but nowhere else. (Harrison, 1975).
The amphibians breed in wet areas.
Flatwoods animals may enter the oak scrub on an intermittent
basis for food and shelter, and species characteristic of xeric
oak may spend part of their time in other habitats.
Animals occupying the xeric oak which are of potential use to
man, are the feral hog and mourning dove.
Longleaf Pine Flatwoods: The overstory consists of an open stand
of longleaf pine on the higher sites with intermixed slash pines
on the lower, wetter sites. Logging has reduced the canopy
closure to less than 10%. This community is present on 5,673
acres of the property. Important in the dense undergrowth are
gallberry, saw-palmetto, fetterbush, wax-myrtle, blueberry,
runner oak, wiregrass, and many other herbaceous species,
particularly grasses and composites. The flatwoods tend to be
more shrubby near the marshes, probably because of increased
moisture and less flammable conditions.
Animal species seen in the flatwoods include the feral hog,
mourning dove, bobwhite quail, cottontail, red fox, opossum,
and deer, all of which are useful to man. Other animals that
are common in pine flatwoods include the southern toad, tree
frogs, glass lizard, diamond back rattlsnake, wild turkey, grey
squirrel, fox squirrel, skunk, cotton rat, least shrew, and
harvest mouse (Rand and Host, 1942; Poppleton et al., 1972;
Layne, 1974). Loss of the pines on the property reduced the
habitat for aboreal species, such as perching birds, tree froes,
and squi rrels.
Ruderal Vegetation: Ruderal vegetation occupies 2,258 acres
where land communities have been disturbed by intensive land
use, mainly improved pastures, row croplands, and citrus groves,
also roadsides, ditches, and abandoned homesites.
The more disturbed areas contain a variety of weedy plants.
Intentionally introduced species include orange, bahia grass,
tomato, and watermelon. The pasture lands have been improved
to various degrees by land clearing and the seeding of bahia.
In many places the native vegetation has become partially re-
established.
No non-domestic animals live or breed exclusively in ruderal
areas. Several are seen commonly in such areas, though. Among
them are the black racer, armadillo, opossum, cotton rat, house
rat, and Norway rat. The red fox, which was introduced widely
in Florida, is often seen in fields (Naggair, 1976a). One was
recorded dead on State Road 62 at Duette during the time of the
survey. The least shrew primarily inhabits old broomsedge fields
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(Golley, 1962) . Birds seen commonly in ruderal areas of the
Swift property are the kestrel, cattle egret, sandhill crane,
corrmon crow, meadow lark, and killdeer. Less common species
are bobwhite quail and mourning dove. Burrowing owls were seen
on an adjacent ruderal site. Many animals breed in ruderal
habitats, especially small marrmals and ground-nesting birds.
The ruderal habitats contain wildlife food plants, including
cultivated crops like corn. The exploitation of these food
sources by animals of nearby natural habitats represents an
interaction betwen ruderal and native cormnun i t i es .
Land-Water Interface - These communities are fresh water swamp
(1,219 acresT^f resh water marsh (600 acres), and cypress (18
acres).
Fresh Water Swamp: Major stream floodplains contain a densely
forested swamp community. The vegetation is heterogeneous,
reflecting the diversity of habitat. Broad intergradations
between vegetational extremes, though, precludes the recognition
of more than one swamp community.
Canopy closure approaches 100% with Laurel oak the most dominant
species, followed by red maple and swamp tupelo. Carolina ash
is important for its high density. Stumps of slash pine attest
to its greater prevalence in the past. The natural restocking
of slash pine appears to be limited to areas where the canopy
is broken and sunlight reaches the ground.
Plants of non-arboreal species are rather sparse, owing to the
shade from the canopy. Understory species include blue dogwood,
American hornbeam, Walter's viburnum, buttonbush, wax myrtle,
storax, and persimmon. Shrubs are scattered or sometimes form
small thickets, especially in bayheads. Epiphytes are
conspicuous and include two orchids, Encyclia tampens i s and
Har r i sella por recta .
The swamps of feeder creeks are characterized by an increase
of trees having broad, evergreen leaves, particularly sweetbay,
swampbay, and loblolly bay. Other common plants are slash pine,
viburnum, blueberry, lizzard's tail, and sphagnum moss . In
Florida such sites are called bayheads, referring to the
predominance of bay trees in headwater sites.
Animals observed in the fresh water swamp are the indigo snake,
raccoon, feral hog, grey fox, and cotton mouse. Other animals
expected are: short-tailed shrew, marsh rabbit, river otter,
opossum, grey squirrel, bobcat, long-tailed weasel, American
alligator, wood duck, barred owl, redbellied woodpecker, blue-
grey gnatcatcher, eastern bluebird, and others, including many
species of migratory birds (Cowell et al., 1974). Animals of
use to man include the feral hog, raccoon, opossum, grey
squirrel, grey fox, otter, bobcat, marsh rabbit, wood duck,
indigo snake, and American alligator.
Fresh Water Marsh: Shallow temporary ponds with emergent marsh
vegetation are scattered throughout the property. These ponds
are catch basins receiving surface runoff during wet seasons
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with maximum depths of 2 to 2.5 feet. The water table drops
just below the soil surface during the dry season in years with
near-normal rainfall, except in the deepest portions where
floating-leaved aquatics grow. Even these deep areas dry out
in years of subnormal precipitation.
The marshes exhibit vegetational zonation with respect to water
depth. The deeper water contains St. John's wort; creeping rush;
mermaid weed; floating hearts; sphagnum moss; species
of Ludwigia and Sagittaria ; pickerelweed; and sawgrass. The
shallower edges support coinwort, spikerush, broomsedge, yellow-
eyed grass, pennywort, and many others. Small thickets of shrubs
are scattered about, mainly occupying slightly elevated spots
within the marsh. Between marshes there is considerable
variation in dominance, and to a much lesser extent, species
compos i t i on.
Birds comprise the largest group of vertebrates utilizing the
marshes. Observed were the great blue heron, little blue heron,
cattle egret, green heron, Louisiana heron, common egret, white
ibis, wood stork, sand-hill crane, belted kingfisher, red-winged
blackbird, brown-headed cowbird, and pied-billed grebe. Other
cornnon vertebrates include mosquitofish, least killifish, golden
topminnow, pygmy sunfish, leopard frog, little grass frog, chorus
frog, cricket frog, mud turtle, musk turtle, American alligator,
rice rate, Florida water rat, and marsh rabbit. Raccoons are
attracted to the abundant crayfish. Feral hogs root about along
the edges of the marshes.
The marshes serve as breeding and feeding areas for numerous
species. Most frogs and toads of the region breed in flatwoods
ponds and marshes (Conant, 1958; Cochran and Coin, 1970). The
larger wading birds nest in trees but require marshes for feeding
areas (Harrison, 1975; Reilly, 1968). The red-winged blackbird,
pied-billed grebe, sandhill crane, and other birds nest in and
near the marshes Burleigh, 1958; Harrison, 1975). Useful animals
include the raccoon, feral hog, and marsh rabbit. Animals that
are largely confined to other habitats may depend on marshes
for water in dry seasons.
Cypress Swamp: A single 18 acre cypress area is comprised of
an interior 5.4 acre shallow marsh surrounded by an overstory
of pond cypress. The sparse understory consist of shrubs and
small trees which grow predominantly on tops of rotting cypress
stumps just above the high water mark. Herbaceous growth is
abundant where openings in the canopy allow light to enter but
elsewhere scattered plants of marsh and serpent ferns and a dense
floating mat of liverworts persists. A St. John's wort,
Triadenum virginicum , heretofore unknown from Manatee County,
wasobserved.
Birds and animals which spend much of their time in other
habitats may use cypress swamps for nesting, protection from
predators, and as a source of water during droughts. Animals
recorded include pig frog, green anole, southern leopord frog,
mosquito fish, red bellied woodpecker, pileated woodpecker, long
sparrow, bobcat, cotton mouse, and fox squirrel
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! - The property contains three stream segments: East Fork
Manatee River, North Fork Manatee River, and the Little Manatee
River. The streams are generally devoid of aquatic plants due
to dense shade cast by the overhanging swamp forests. A few
areas that lack a dense canopy, though, support growths of
spatter dock, evening primrose, para grass, pondweed, alligator-
weed, and Ni tella sp. Interruptions in the canopy are often
the result of disturbance by man.
i s
Stream Metabol ism: Little submerged or emergent vegetation
present and the lack of vegetation is reflected in low gross
primary productivity. Corrmun i t y respiration was also low.
Respiration exceeded production indicating the stream system
relies on an outside source of energy. This conclusion is
corroborated by the oxygen saturation data. The dissolved oxygen
level was always less than saturation i ndi cat i ng more organic
matter is being consumed than produced (Odum and Hoskin, 1958).
Fifty-three periphyton taxa were identified with fourteen species
accounting for about 90% of the total periphyton abundance
Corrmunity characteristics such as density, biomass, and species
richness indicated natural spatial and temporal variation, while
species diversity was more uniform.
The two Manatee River segments exhibited a greater species
similarity to each other than to the Little Manatee River
segment. Lack of marked temporal change in the periphyton
corrmunity was ecologically significant in delineating the Little
Manatee River segment.
The aquatic environs at the Duette Mine site appears to be a
detrital based system ( heterotrophi c ) . Characteristics of the
periphyton community (e.g. dominance, density, species richness
etc.) appear to reflect the natural state of such a system. '
Benthos: As previously noted the aquatic environment is generally
devoid of benthic macrophytes. Benthic macroi nver tebrate
communi ties are characterized by dominance by few species,
abundance of detrital feeders (scavengers and omnivores)
abundance of "clean" water species, moderate density and'biomass,
and high species richness and diversity. Overall the benthic
corrniuni ties appear to be characteristic of "clean" (sensu Beck,
1954; 1955) water conditions of a detrital based system
Substrate and seasonal temperature differences do not appear
to alter substantially the benthic corrmunity structure at the
study area.
nQ°rUnt!S: ^ fiSu P°Pulati°ns are typical of Barnett's
(1972) Narrow Streamlet Habitat. The dominant species are
spotted sunfish and largemouth bass. Both fish are predators
the sunfish preying on small fish and invertebrates while the'
bass feeds on larger fish and invertebrates. The low density
of smaller fishes is probably due to the lack of cover which
makes them more available to the predators
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jmpact_
Table 4.12-A compares the acreages of the present natural
communities and those that will survive mining operations or
be restored by reclamation.
Land - The direct effect of mining will be the physical
destruction of much of the present natural vegetation by land
clearing/mining activity. The longleaf pine-xeric oak corrmunity
will be eliminated on-site while the sand pine scrub corrmunity,
longleaf pine-xeric oak corrmunity, and longleaf pine flatwoods
community will be partially eliminated (Table 4.12-A). An
overall 85% loss of native upland vegetation represents the
magnitude of mining effects.
Table 4. 12-A Acreages Before Mining and After Reelamation(1)
Sand Pine Scrub (2)
Longleaf Pine-Xeric Oak
Xeri c Oak (2)
Longleaf Pine Flatwoods (2)
Fresh Water Swamp (3)
Fresh Water Marsh (4)
Cypress Swamp (2)
Improved Pasture
Row Crops
Orange Groves
Mixed Forest
Lakes
Abandoned Mining Operations
Present
Acreages
73
35
518
5,673
1,219
600
18
1,677
468
113
0
0
0
Acreages After
Reclamation
50
-S \J
o
\J
89
829
1 , 228
864
18
6,642
107
JL \J f
25
£. -S
58
-^ O
100
10,394 10,394
(1) Data from Swift Agricultural Chemical Corp. (1978-
DRI/ADA No. 770861 and Addendum).
(2) Acreages after reclamation represent unmined lands that
still contain the vegetation present before the
corrmencement of mining operations.
(3) 476 acres of natural vegetation lost, mostly from along
ofri?h!aFy trS6kf ^a,nd bavheads> als° from along 4,000 flet
of the East Fork Manatee River which will be mined. Fifty-
five acres will be recreated by planting saplings of
native species at a density of 60 saplings per Icre along
the recreated East Fork Manatee River 8
+ 0f nftural ^getation will be lost from mining
Some additional acreages will be disturbed or lost
from construction of roads, railroads, pipelines
powerlines, and from the crossings of draglines.'
It is expected that these effects are largely long-term and
irreversible. There are no known instancl of" theL upTan2
communities naturally re-establishing and fully recovering if
the soil is radically disturbed. Various authors have assumed
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that these communities represent serai stages, but development
of these corrmuni ties has not been reported. Some of the dominant
species readily invade disturbed sites but others (e e
wiregrass) have negligible reproductive potentials Reclamation
is designed to replace most natural land communities with
improved pasture, thereby largely precluding the r e-eTtabl i shment
"'8 vegetation, even if it wer/bi ologi cal !y possTb?e
to so
Not all sites containing native upland communities will be
Tn2e?;«,IJYr?antS °f Uf>Iand Yegetation wil1 Primar y be small
and isolated between swamps and/or improved pastures. Since
the natural upland vegetation is dependent on fire for its
maintenance, and since fires will likely be excluded from the
c™sm^eV7o7Stand Pastures? Prolonged fire supress^n wi 1 1
constitute a long-term or even irreversible impact!,
The significance of mining will be a substantial loss of natural
.
Animal use is relatively low, as was previously noed? Deer*
fera hogs, and other larger animals will move into suitable'
habitats nearby during mining operations. Most suitable habitats
*
f™' - ngWc s anta
lorm of recreation in the region. Mice and other small animals
will be less ikely to escape and will suffer major redu??ions
in their populations. Some of these smaller speci es Hkel i wi I I
adapt to the habitats created by reclamation. Y
Some acreages containing natural corrmuni t i es are not scheduled
for mining but may be affected by related activities These
activities include the "walking" of dragl i nes be ween mine s i tes
mitigative measures are proposed. «»*non or otner
During mining, the ground-water table will be lowered beneath
'"'- « -
-
thereafter. The magnitude of dewatering would be eau valent
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to plants. Many animals would adjust by moving a short distance
to adjacent areas where more mesic conditions prevailed.
Levels of dust and other emissions will increase during mining
operations. Other than radioactive nuclides which are treated
in another section, the only component of these emissions of
potential impact to plants and animals is fluoride. Fluoride
varies in degree with the species, the fluoride concentration,
and the chemical form of the fluoride. Gaseous fluoride
compounds may be generated during mining operations in minor
quantites from the dryers. The high rainfall in the region will
cleanse the vegetation of rock phosphate dust at frequent
intervals, thereby reducing the potential for fluoride toxicity.
Studies in Polk County (Environmental Protection Agency, 1978)
showed that vegetative fluoride content varied with the amount
of rainfall, demonstrating this cleansing effect. After entering
the soil, fluorides are scarcely if at all absorbed by roots.
Fluoride emissions apparently will constitute a short-term, low
magnitude impact that will cease upon the completion of mining
operations without residual effects.
Other emissions, including $©2 and radionuclides, will occur
at such low levels as to constitute no discernible impact on
the biota.
Land-Water Interface - Mining will destroy 476 acres of fresh
water swamps and 364 acres of fresh water marshes. The 18-acre
cypress swamp will be unaffected (Table 4.12-A). Reclamatin
is planned to restore these acreages and contribute others for
a net gain of 15%.
The regrowth of fresh water swamps will be slow. Several decades
of tree growth are necessary before a mature forest develops.
Tree establishment might be delayed in places because of
unanticipated problems in stabilizing the substrate of the
restored flood plain. Full stocking may be delayed because of
the intangibles associated with the natural dispersal of seeds
and other propagules from undisturbed flood plains nearby. The
initial forest cover likely will resemble that presently
occurring on the flood plains of the major streams, rather than
those of bayheads. Sweetbay, swamp bay, and other species that
are more common in bayheads will likely remain relatively
uncorrmon until peaty acid substrates gradually develop along
the minor tributaries.
Fresh water marsh restoration should be more rapid. Emergent
and shallowly submerged aquatics readily invade borrow pits,
clay settling ponds, and other newly created wet habitats in
the region. It is likely that cattails will become dominant,
perhaps to the exclusion of all other emergent species. This
effect would occur in the littoral zones of newly created lakes
but would be more pronounced in the swales and marshes that will
be formed by subsidence at the outlet ends of sand-clay land
fills. Once established, dense growths of pure cattails may
persist indefinitely. as long as water levels are seasonally
deep enough to exclude seedlings of willow, buttonbush, and other
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woody plants.
Animal populations closely associated with the shal low marshes
wi 11 be reduced initially as a result of mining, corresponding
with the on-going loss of habitat and the activity inherent with
TJn™gt°TatTS- ,As marsh restoration will alsOy be ongoing
as part of land reclamation, most or all of these populations
^JVin/T^V; Pre-min!"g levels upon the recreation of
wetlands habitats, assuming no interference from cattails.
In summary, the effect of mining on marshes will be short-term
^M,regar? *S thej;aPidity °f ™<-sh re-establishment on
mnJi aimed lands; Jhe probability of cattails predominating in
much of the reclaimed marshland may constitute a long-term
With re*ard to 'Pecifs diversity
mavhn.tSi?n,iineS' r°ads' and other structures that
may be bu t across 15-20 acres of wetlands not scheduled for
mining will create a disruptive influence on the vegetation?
These disturbances will be short-term in places and long-term
elsewhere. Unlike in the uplands, swamp and marsh vegetation
has the capacity to establish itself readily after stable
substrates and suitable hydroperiods are attained.
beneathan^ih? d"ring actual mining will lower the water table
beneath nearby natural swamps and marshes that are not scheduled
a'timT'th^h'T CaU-f°r mining °ne Side °f a "oodp?ain at
f™ H \ ^ f X, dePressinS wat«r tables minimally. Reclamation
immediately following mining will allow the restoration ™*ll°n
previous ground-water levels. During dewatering, the lowered
d?o^httablThmay haVe thC S3me GffeCt as a Prolonged nauTa
drought. The vegetation will be stressed, especially if rainfall
is subnormal during the growing season. Nonetheless, Jhese
conditions occur naturally about every two decades w thout lone
term harm to the native vegetation. witnout long-
.h-.-f.-a;^-"-- thsh
land or land-water interface vegetation except for ?he fresh
P
Trill SWcTr; Fjre-tender hardwoods could be ki 1 led over wide
areas. Cypress trees are f i re- tol erant and would be unaffected
unless a ground fire develops in the peat. The possibiHtv of
is unlikely in years of normal rainfall. l%nill°n 01 a swamp
Water - Various mining activities will result in the destruction,
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alteration, and/or restoration of aquatic habitats as well as
the creation of new habitats. Among the new habitats will be
several large lakes, a type of habitat not presently existing
in the vicinity of the mine site.
The direct impact of mining will be the complete destruction
of some aquatic habitats, primarily small, intermittent
tributaries. The magnitude of this effect is measured by the
loss of 417 acres of ephemeral feeder streams and their flood-
plains. In addition, plans call for mining of approximately
4,000 ft. of the East Fork of the Manatee River, one of the major
streams on-site.
Mining of the streams will result in the destruction of many
of the indigenous animals, although some, especially the fishes,
will be able to flee to adjacent undisturbed areas. Even so,
this does not assure their survival. Populations in the adjacent
areas are probably already at their carrying capacities and
increases in their populations would be countered by increases
in predation and disease and a decrease in reproduction. When
populations had again stabilized, the densities of animals would
approximate levels present prior to mining. Thus, there would
be a net decrease in numbers proportional to the decrease in
habi tat.
An indirect effect of mining operations will result from the
projected short-term loss of adjacent floodplain forest. This
will result in a decrease in the amount of detrital input to
the aquatic system. The streams on the site are highly
heterotrophic. Detritus from the fresh water swamps is an
important source of energy to the streams, the reduction of which
will result in a reduction in the carrying capacity downstream.
Swift proposed restoring the mined section of the East Fork and
430 acres of the tributaries. The effect of the restoration
is discussed later.
The streams will be crossed at several points by pipelines,
permanent and temporary roads, power lines, and a railroad!
The draglines will be "walked" across the streams several times.
These activities not only result in the destruction of small
areas (totaling approximately 15-20 acres) but can also alter
the character of the streams for considerable distances
downstream.
One effect of these activities near and across the streams is
to open the flood plain forest canopy, allowing more sunlight
to reach the water. At the present time, the shade from the
forest canopy severely limits the growth of aquatic plants.
Where breaks in the canopy now occur, there are dense growths
of emergent and submerged macrophytes, especially alligator weed,
Al ternanthera philoxeroides ; pondweed, Potamogeton
diversifoliua ; spatterdock, Nuphar luteum ; and stonewart,
Nltella SP- These species will expand their populations
wherever the canopy is broken. Periphyton will increase because
of the increased light and the increase in substrate provided
by the aquatic macrophytes.
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The change will have a positive net impact on small fishes and
invertebrates. The macrophytes will provide shelter from
predation for insect larvae, crayfish, grass shrimp, and small
fishes, allowing them to attain higher densities than in areas
devoid of plants. In addition, the periphyton will be an
additional source of food for many of these species. The changes
will be long-term but will be reversed when new tree growth
closes the openings in the canopy (15-20 years).
The increased sunlight reaching the water will also cause a rise
in water temperature (Burns, 1972). The change is not expected
to be of a magnitude which will significantly effect any of the
species now present.
An indirect effect of the stream crossings is an expected
increase of erosion. Erosion runoff can cause serious short-term
negative impacts largely due to the suspended solids carried
by the runoff water. Suspended solids damage aquatic corrmuni t ies
by reducing light penetration (thus reducing photosynthetic
activity), smothering benthic organisms, destroying spawning
areas, and abrading and clogging the gills of fishes (Bennett,
1970; Cairns, Lanza and Parker, 1972; Lackey, 1975). The effects
of erosion are quickly reversed following abatement. Barton
(1977) reported that erosion from highway construction increased
sediment deposition in a nearby stream ten-fold, while suspended
solids increased more than two hundred-fold. This resulted in
a reduction in the standing crop of fishes irmiediately below
the construction site by more than half. No effects were
detected further downstream, however, and population levels at
the construction site returned to normal within eight months.
Little disruption of the flow in the streams is expected due
to mine pit dewatering (Ardaman & Associates, Inc., 1975), hence
there will be little impact on the aquatic biota.
Discharges into the North and East Forks from the water
recirculating system may contain a number of substances which
may have subtle impacts on the aquatic biota. Potential
pollutants include clay wastes, phosphate, flotation reagents,
and sewage effluents. Water samples collected at Swift
Agricultural Chemical Corporation's Silver City Mine (CCI 1978)
showed elevated concentrations of phosphate, arrmonia, dissolved
solids fluorides, and zinc. With the exception of anmonia,
the Silver City Mine effluent may be considered representative
of the nature of discharge expected.
Arrmonia, fluorides, and zinc are toxic in varying degrees to
aquatic organisms (Cairns, Lanza, and Parker, 1972; McKim et
al., 1976; Herncks and Buikema, 1977). The toxicity of each
varies from species to species, but prolonged elevation of
concentrations of these chemicals in the streams would lead to
a long-term reduction in the diversity of the biota. The
infrequent planned discharges of these chemicals at
concentrations comparable to the Silver City Mine effluents
should result in minor short-term impacts.
Arrmonia and phosphate are plant nutrients. Phosphorus and
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nitrogen have been identified as the primary nutrients
contributing to eutrophication (Brezonik et ai., 1969). However,
rivers draining this area of Florida naturally have high
phosphorus levels (Dragovich and May, 1962; Dragovich, Kelly
and Goodell, 1968). Nitrogen levels in this area are normally
low (Dragovich and May, 1962) so that the lack of nitrogen may
be limiting to the rate of eutrophication. Eutrophication is
a long-term negative impact which is not readily reversed. It
usually results in shifts in species composition toward nuisance
species and a reduction of diversity.
Phosphate mining will create several lakes on the Swift site.
This is a significant expansion of the aquatic environment and
can be considered a positive impact of mining. Lakes created
by phosphate mines are known to support sizable fish populations
(Crittenden, 1965). Species which now occur on the site and
which may be expected to expand into this habitat include the
Florida gar, golden shiner, lake chubsucker, brown bullhead,
mosquitofish, bluegill, largemouth bass, crayfish, grass shrimp
and many of the insect larvae.
The segment of the East Fork of the Manatee River and 430 acres
of the intermittent streams which are to be mined will be
restored. The native fauna should rapidly recolonize this area
since aquatic invertebrates (Williams andHynes, 1977; Chisholm
and Down, 1978; Kaster and Jacobi, 1978) and fishes (Gunning
and Berra, 1969; Berra and Gunning, 1970) have been observed
to recover rapidly in other disrupted streams. Initially, the
flood plain forest will be poorly developed, resulting in small
detntal inputs and high light intensity. Until the forest
canopy becomes well established, aquatic macrophytes and
periphyton communities will be well developed. These communities
will decline as the shading from the forest canopy increases.
Eventually, the restored stream segment should be representative
of a natural stream. K
Mitigating Measures
The mining and reclamation plan incorporates several structural
and nonstructural measures intended as safeguards for the
environment and biota of the site. These safeguards are treated
below under three headings: planned preservation areas
safeguards during mining, and reclamation benefits.
Planned Preservation Areas - Significant mitigating measures
associated with the proposed activity are related to the mine
planning effort of the applicant. Natural vegetation considered
sensitive or unique was specifically identified, ranked, and
mapped prior to formulation of the mine plan. Associations
marked for prime consideration by the mine planners included
the sole cypress stand of the site (18 acres), two stands of
sand pine scrub (23 and 50 acres), and the entire floodplains
of major streams, as identified by the dominant vegetation.
As Proposed in the mine plan of the applicant, the cypress stand
is entirely excluded from the mining plan, as is the larger stand
of sand pine scrub. The wooded floodplains of the major streams
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are also excluded with the exception of a three-quarter mile
segment of the East Fork Manatee River which is proposed for
mining and subsequent reclamation as a swamp.
In addition to preservation of the above described areas the
environmental value of 829 acres of pine flatwoods not scheduled
for mining will be improved. These flatwoods remained
understocked with pines ever since the original timber harvest
several decades ago. Seedling pines will be planted at a density
of 100 per acre in an attempt to re-establish the original forest
cover.
Safeguards During Mining - The quantity of fugitive dust that
could settle on the vegetation in the vicinity of mining
operations will be reduced by spraying water regularly on the
well traveled roads. Air emissions will be kept within
applicable standards further protecting the biota that is not
disturbed or destroyed by mining.
Exposed soils of reclamation areas will be planted with cover
crops as soon as possible to prevent erosion and consequent
sedimentation in streams.
In-system water recycling and the attendent minimization of water
discharges from the plant and settling pond will reduce the
potential for water pollution both on-site and elsewhere. If
excessive water accumulates after exceptional rainfall events
this excess will be diverted into clarification ponds before
it is released into natural streams. Water quality will be
monitored daily at permanent stations to insure that discharges
into streams meet applicable standards.
In an effort to protect wetlands along streams, the mine plan
incorporates active mining along only one side of a wetland at
a time. The mine pit will be filled before the other side is
mined. As a result, the base flow of ground water into these
wetlands will never be severed entirely and the potential for
the wetland vegetation suffering from water-stress during mining
will be reduced. 6 5
Mining will not take place within 200 feet of any retained flood-
plain. As a result, base flow into streams will be maintained
at near normal levels even on the side of a stream being mined.
On the long-term, it is estimated that base flow that enters
streams will be reduced by no more than 1.5% after reclamation.
The possibility of leakage from pipelines crossing natural
streams will be reduced by the use of retention dikes at the
outer edges of flood plains and by the construction of double
walled, trestled pipelines over floodplains. If leakage should
occur, it will be detected quickly by an alarm system fha? is
activated with a change in pressure in the pipeline.
The mining of the East Fork Manatee River will be mitigated bv
the prior diversion of stream flow through a newly created
meandering stream bed and 55 acres of flood plain. This new
floodplain will have been planted initially to grasses for soil
134
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stabilization and then to native bottomland hardwood trees, with
hopes of speeding forest development. There will be no mining
upstream until the new channel has been properly established.
As a result, water quality downstreams will be not be degraded.
Reclamation Benefits - All reclaimed land will be revegetated
to minimize erosion. Physical land restoration will be completed
within three years after the inception of mining in a given area
(one year for mining and two years to fill the mine pits with
tailings or a sand-clay mi x). Water tables will be re-
established after reclamation. This effect will be irrmediate,
because the pits will be filled by an aqueous slurry of tailings
and sand-clay mix. As a result, the natural vegetation of
surrounding unmined areas will not suffer prolonged water-stress
i f any at al1. '
The sterile, excessively drained sand tailings fill areas will
be spread with overburden or sand-clay mix, which have better
soil characteristics allowing faster revegetation. Reclaimed
lands will be planted to a sod of Bermuda grass, bahia, and white
clover, which will promote the rapid incorporation of organic
matter and thus the development of a top soil. Hedgerows of
native trees will be planted on about 1% of this land, providing
escape cover for wildlife. Patches of Eucalyptus will also
be planted to serve as cattle shade.
The re-establishment of swamps and marshes is a major feature
of the reclamation plan of the applicant. Fifty-five acres will
be planted to native bottomland hardwoods at a density of 100
trees per acre in the reclaimed East Fork Manatee River after
mining. Minor tributary creeks leading to the larger streams
will largely be mined. They will be replaced by an additional
430 acres of reclaimed lands which will be planted to native
bottomland hardwoods. The native marshes occurring in flatwoods
depression that will be lost during mining wi 11 be replaced by
similar depressions on reclaimed lands. These depressions will
be allowed to revegetate naturally. There will be a net gain
of nine acres of fresh water swamps and 264 acres of fresh water
marshes after reclamation.
These marshes and swamps are to be located so that they may serve
as clarification and nutrient filtration areas for runoff before
entering the major streams. They also form a continuous network
of native vegetation which will serve as corridors for wildlife
Mine pit lakes resulting from reclamation are integrated with
these corri dors.
Reclaimed lakes will contain a substantial littoral zone
(approximately 10% of lake area) which will enhance their
biological productivity. A 100 acre area adjacent to the
northernmost reclamation lake will intentionally be left largely
unreclaimed. The series of steep windrows of spoil will be
topped and allowed to revegetate by natural means and in time
will serve as roosting areas for water birds. The rugged terrain
will discourage predators (and people) from disturbing these
roos t s . °
135
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Rare and Endangered Species
Several lists of endangerd species are in current use. Those
which apply to the Swift mine site are the Endangered Species
Act of 1973 (Code of Federal Regulations: Title 50, Chapter
I, Part 17), Florida Game and Fresh Water Fish Commission (1976),
and Florida Committee on Rare and Endangered Plants and Animals
(1976). In addition, the Smithsonian Institution has prepared
a list of plants which are proposed for inclusion in the
Endangered Species Act list (U.S. Fish & Wildlife Service,
1976). Each list uses the term "endangered" for those species
facing the greatest danger of extinction. "Threatened" is used
for species in less danger. The Florida Corrmittee on Rare and
Endangered Plants and Animals adds the categories "rare" and
"species of special concern".
All federally-listed and state-listed species that would be
reasonably expected on the Swift property are listed in the
Biology and Ecology Resource Document. A special effort was
made during the field investigations to look for these species
on the proposed mine site.
Sixteen endangered, threatened, rare, or special concern species
have been observed on or inrmedi ately adjacent to the Swift
property. Of the sixteen observed species listed, none were
considered as endangered on the federal lists, but three were
listed as threatened. They were: pinweed, eastern indigo snake,
and American alligator.
Federally Recognized Species - The habitats for pinweed (sand
pine scrub and xeric oak) will be reduced in area by mining
operations. Since these habitats will not be restored by
reclamation, pinweed populations will suffer a reduction through
mining operations. The eastern indigo snake will decline in
numbers with the destruction of swamps during mining but should
recoup their former numbers after reclamation is completed.
The alligator will decline somewhat during mining but will
increase substantially above present population levels with the
addition of 384 acres of lakes and a 15% increase in other
wetlands when reclamation is completed.
State Recognized Species - Thirteen species sighted were
recognized only on state lists. One was endangered (wood stork),
five were threatened (gopher tortoise, southeastern American
kestrel, Florida scrub jay, Florida sandhill crane, Sherman's
fox squirrel), and seven were of special concern (common egret,
Louisiana heron, black-crowned night heron, white ibis, little
blue heron, burrowing owl and carracara).
Wood storks are sometimes seen in clay settling ponds and may
increase their numbers on the property during mining operations
as the proposed settling pond becomes available for their use.
The swales, marshes, and wet pastures of the reclaimed land will
1ikely attract them, assuring that present population levels
are maintained or even increased.
The gopher tortoise will decline during mining operations but
136
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will regain or even exceed its former numbers following
reclamation. These land turtles are common on formerly strip
mined sites. The abundance of well drained slopes will favor
their return on reclaimed lands.
The southeastern American kestrel will decline during mining
operations. The probable lack of thickets in the vast expanses
of improved pasture may prevent this hawk from regaining its
present population size.
The Florida scrub jay may be driven off the property during
mining operations. The likelihood of the return of this species
is reduced because of the reduction in acreage of its scrub and
xeric oak habitats.
Florida sandhill cranes will tend to move off the property during
mining operations but will return in approximately their present
numbers following the restoration of marshes and swales.
Sherman's fox squirrel may survive mining operations in the
cypress swamp or other unmi ned habitats, although this
possibility is not assured. If pine flatwoods are successfully
restocked in the restoration effort, the fox squirrel may
eventually become conrmon on parts of the property.
The several wading birds listed by FCREPA (1976) as species of
special concern. All should continue to utilize the wetlands
of the property during mining operations. All may increase in
numbers after reclamation because of the addition of lakes and
the creation of marshes and swales.
Some other species that might utilize the site deserve further
comment. Panther and bear are wide ranging animals that could
pass through the Swift property in the fresh water swamp
community along streams. They would likely be transient, because
the surrounding uplands have been too great 1y modifled for their
use. The red cockaded woodpecker lives nearby (Hirth and Marion,
in press) but is not expected on the Swift property for lack
of sufficient old-growth pines. In time nesting colonies might
occur there, as long as the present pines are allowed to mature
and if former pinelands are restocked.
The Florida mouse may occur in the pinelands but would have been
overlooked, because traps for small mammals were not set. The
gopher frog, which is a commensal living in the burrows of gopher
tortoises, may also have been overlooked, because gopher burrows
were not disturbed during the field investigations. The
burrowing owl was seen a short distance away on adjacent property
and may well frequent the Swift property.
Bald eagles, ospreys, and caracaras might make occasional visits
to the Swift property, but the present complex of habitats would
not be particularly attractive to these species. Additional
details on the regional status of these animals are given by
Layne et al. (1977). & 3
137
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Environmentally Sensitive Areas
Basel ine - This section assigns environmental sensitivity values
to the various attributes of each corrmuni ty/habi tat . An area
is considered sensitive if it meets one or more of the following
criteria:
o Contains endangered or threatened species which cannot
survive elsewhere.
o Fulfills an important function, such as aquifer recharge
or high wildlife capacity.
o Represents a unique or rare corrmun i t y or habitat in west-
central Florida.
Twelve attributes were evaluated on a scale of 1 to 5 (Table
4.12-B). Other potential attributes were omitted because they
do not represent land uses (e.g., camping, hiking) or natural
processes currently associated with the Swift property.
The assignments of some values were necessarily
subjective for lack of sufficient observations or data.
Table 4. 12-B Environmental Values
'
Habitat
Row Crops
Citrus
Improved Patures
Sand Pine Scrub
Xeric Oak
Pine Flatwoods
Marsh
Swamp
Cypress
Lake*
Wilderness*
Mixed Forest*
Stream
CO
c
•r—
IO
i.
0
5
5
1
3
3
2
1
3
.3
4
5
2
3
.S
ta
n:
to
QJ
•r—
O
OJ
Q_
00
OJ
i.
OJ
CD
C
i.
3
5
3
3
3
2
1
1
1
1
2
2.5
2
CJ
-Q
•r—
h-
3
3
3
3
3
3
3
2
2
5
5
1
3
en
C"
-C
to
•r—
Lu
3
3
3
3
3
3
3
3
3
1
3
3
2
C7)
•f_
4->
3
2
3
3
3
3
2
2
1
2
2
3
2
1
o
•M
CJ
•M
to
O)
5
4
5
1
2
2
1.5
1
1
2
4
2.5
1
O)
CD
(O
J_
O
oo
co
i.
to
-C
o
OJ
ac.
i.
OJ
•r—
CT
3
3
3
3
3
3
3
3
3
3
3
3
3
•M
•r—
to
Cr
OJ
3
5
5
4
2
2
2
2
2
2
3
4
2
3
i—
o
i.
c
o
o
c
o
•r—
I/)
o
s_
LU
4
5
4
1
1
1
1
2
1
4
5
2
5
_^
(O
OJ
s_
co
OJ
J_
1
4
2
2
5
5
1
2
1
3.5
4
5
Habitat to be created by reclamation and not part of the present landscape
Values: 1 - H1gh posntive value 4 - Low negative value
I ~ Low positive value 5 - High negative value
3 - Neutral; without effect with
regard to the attribute
138
-------
Only those assigned values in Table 4.12-B that are not self-
evident are discussed below.
Water Storage: Wetlands are generally considered prime water
storage areas during dry seasons. Streams are exceptions,
because they export water when the water table is above the level
of the streambed. In the region of the proposed mine, the water
of marshes and hardwood swamps is probably the result of base
flow of the groundwater from adjacent areas. The water table
of wetlands is exposed and, therefore, subjected to loss through
evapotranspiration. Such a loss in water is not characteristic
of the adjacent uplands, because soil water does not rise through
the sands to the surface by capillarity (Woods, 1957) and because
the feeder roots (responsible for water absorption) are nearly
all s uper f i ci a 1 .
Cypress swamps may be exceptional because the shade from cypress
trees reduces evaporation from the pond surface (Odum, 1976),
and perhaps because water absorption and thus transpiration are
reduced by the high acidity of cypress ponds. The values in
Table 4.12-B reflect these considerations.
Aquifer Recharge: Table 4.12-B shows a neutral value of 3 for
all communities, because available evidence indicates that there
is minimal recharge occurring on the proposed mine site (Ardaman
<5c Associates, Inc., 1975). Recharge of the confined Floridan
aquifer sometimes occurs only at remote localities within a large
region (William F. Guyton & Associates, 1976). Most cypress
heads in peninsular Florida are underlain by confining beds of
clay which prevented recharge of the Floridan aquifer (Ewel,
1976).
Water Quality: Water quality values were assigned on the basis
of potability. The soils of natural communities do not degrade
water quality and may improve it by the absorption of ions to
their colloidal surfaces. The stream is considered neutral.
Heterotrophic metabolism likely results in the mi neralization
of nutrients which go into solution, degrading water quality.
This effect may be slight because of the low metabolic rates
in streams and may be offset by the oxygen added by agitation
of the f1owing water.
Erosion Control: Erosion is a continual process in flowing
streams. Streams are given high negative values for erosion
control, accordingly. Natural communities are characterized
either by standing water or by dense superficial root mats that
bind the soil. These are given high positive values for erosion
control. Freshwater swamps are exceptions over long time spans,
because colluvial transport occurs and gradually enlarges
valleys. Improved pastures are likely subject to some erosion
due to a less effective root mat than in natural corrmunities
and to soil exposure caused by trampling.
Vertebrate Production: The values for this attribute are
indicative of the relative biomass of all non-domestic vertebrate
animals.
139
-------
On the basis of the environmental values in Table 4.12-B the
environmental sensitivity of the existing corrmuni t i es/habi tats
can be judged. A corrmuni ty/habi tat is sensitive if it contains
rare and endangered species that are unable to survive and
reproduce in any other kind of habitat, if it fulfills an
important function or beneficial "service", or if it is uniaue
or rare in west-central Florida. unique
Rare and Endangered Species: None of the habitats at the
proposed mine site can be identified as being particularly
sensitive on the basis of the rare and endangered species seen
*• 11 L 11 "111 »
Fulfillment of an Important Function: Table 4.12-B shows that
each community performs some beneficial "services". No community
or communities stand out as being far superior to the others
and none are particularly inferior. A reason for this apparent
equity is that the properties that combine to make a corrmunity
superior for one function may make that corrmunity inferior for
another function.
The destruction of a swamp forest has a profound effect on water
quality downstream, on aquatic corrmunities in the streams, and
on populations of terrestrial animals that primarily inhabit
other corrmunities. These and other negative impacts caused by
the destruction of swamps are listed in the regulations
pertaining to Section 404 of the Federal Water Pollution Control
Act, published July 19, 1974 (Federal Register 42(138: 37136).
For these reasons, the fresh water swamp corrmunity is designated
as environmentally sensitive.
Unique or Rare Corrmunities: The sand pine scrub corrmunity is
the only corrmunity on the Swift property that is not particularly
abundant in west-central Florida. It occurs only in Florida
and in one adjacent county in Alabama. It is distributed
irregularly and often in small stands. Many or most of these
stands have been destroyed and the sites converted to citrus
groves or urban developments. Some of the component species
aggressively invade culturally disturbed sites, but active serai
development that leads to the establishment of the entire
corrmunity has not been observed. Present evidence suggests that
the community is relictual and that its destruction constitute?
an irretrievable loss of habitat. aniuies»
The sand pine scrub community may be considered to be marginally
sensitive and will become more so as future land use impinges
on its habitat. °
ImPacts - Jt was assumed that there would be no change in
environmental values after mining and reclamation for a given
community/habitat. The values in Table 4.12-B assune thft values
are similar for a re-established site as for the present
conditions. It is questionable, though, as to whether or not
the swamps and marshes that will be created on mined and
reclaimed lands will have the same environmental values that
were assigned to natural swamps and marshes. Natural habitat
140
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restoration as proposed for the Swift site has not been attempted
previously. Prototypical studies are being initiated on some
mined lands in central Florida, but the results are not yet
available. It would be improbable that the restored marshes
would have the exact species composition and dominance patterns
as in natural marshes, at least initially.
Cattails were absent on the natural marshes studied on the Swift
property (Biology and Ecology Resource Document), but they
dominate the marshes of abandoned clay settling ponds throughout
the Central Florida phosphate district. Since cattails
aggressively invade ditches, reservoirs, and other newly created
wet sites with mineral substrates, it is possible that they will
be important in the newly created marshes on the sandclay fills
proposed for the Swift property.
Since there is no method of determining with confidence the
environmental values of newly created swamps and marshes on
reclaimed lands, it was assumed that the environmental values
of natural habitats are coincidental with those of recreated
habi tats.
Lakes: The emergent and shallow submerged aquatic plants of
the littoral zone will be utilized by cattle, thus a grazing
value is appropriate, although lower than that of the improved
pastures that these lakes replaced. Lakes will attract wood
storks, the large wading birds of special concern, alligators,
perhaps eagles, and other rare and endangered species. The
biomass of fish and reptiles and their high turnover rates
contribute to high vertebrate productivity. The timber value
is rated low, rather than neutral, because presently wooded
habitat is being replaced by lakes. The water storage value is
better than that of swamps and marshes because of a better
surface-to-volume ratio, less emergent aquatic vegetation that
promotes transpirational losses, and probably a partial cover
of water hyacinths that will reduce evaporation. The banks will
be subject to wave action, causing some erosion.
Wilderness Area: The wilderness area will consist of spoil piles
which will be allowed to become revegetated by natural means.
The vegetation of similar sites throughout the central Florida
phosphate district consists of woodlands which do not closely
resemble any indigenous plant communities in structure or species
composition.
Gross production will be relatively low because of the sparse
growth of brushy vegetation that will occupy these slopes for
at least several decades. The steepness of the slopes will
retard the establishment of more luxuriant vegetation. This
vegetation will have a low aesthetic value. The angle of slope
will cause continual erosion in wet seasons. Vertebrate
production may be high, either from nesting birds attracted to
the lake and partially isolated from predators, or from rodents
that are also partially isolated from predators.
Mixed Forest: The values for this habitat are about the same
as those for other wooded habitats. The value for grazing is
141
-------
high and that of fire break capacity low, assuming incomplete
canopy closure and a grassy undergrowth.
Mi tigation - Not all areas of the property will be mined or
irrevocably disturbed. Approximately 761 acres of floodplain
swamps will be spared from mining and will be preserved without
modification. Fifty acres of sand pine scrub and the 18-acre
cypress pond will also be preserved. Normal water tables will
be resumed shortly after mining, thereby minimi zing the period
of stress and the resultant loss of plant life from desiccation.
The use of a sand-clay mix in reclaimed sites should create soils
that are more fertile and have a higher water retention than
the natural soils. As a result, improved pastures on the
reclaimed lands may have higher yields than at present.
There will be a net increase of swamp forests and marshes after
reclamation assuming proposed reclamation technologies are
successful. The swamps will be planted and the marshes will
be allowed to develop naturally on reclaimed land. As noted
above, it is unknown whether or not the swamps and marshes on
reclaimed land will have as high a value as they presently have.
The lakes created by mining will have positive environmental
attributes. Their wide littoral zones will enhance their
potential for high biological productivity.
142
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5.0 DESCRIPTION OF BASELINE, IMPACTS AND MITIGATING MEASURES
OF THE MANMADE ENVIRONMENT
5.1 DEMOGRAPHY
Base 1i ne
Number of Inhabitants - Regional - The U.S. Census Bureau
announced in 1976, that for the first time in United States
history, the majority of the population resided in the south
and west. This growth is primarily a result of migration out
of the north and into the "Sunbelt".
Florida has been a primary recipient of this irrmigration for
several decades. During 1970-77 the state's population grew
irom 6.7 million to an estimated 8.7 million, a gain of 28%
according to the Florida Statistical Abstract.
a
The migration of new residents into the state is primarily „
result of climatic and other natural features. In addition to
this historic trend of retiree orientation, Florida is also
witnessing an increase of the younger immigrant seeking work
or being given the opportunity to relocate because his employer
is establishing Florida facilities.
For numerical analysis of Florida's population in the area
centered around the phosphate industry, this survey will make
use of demographic statistics reported in the Areawide Central
Florida Phosphate Industry Environmental Impact Statement
(Areawide EIS) recently prepared by EPA for the Council on
Environmental Quality. The seven counties included in the
Areawide EIS are Charlotte, DeSoto, Hardee, Hi 11sborough,
Manatee, Polk, and Sarasota.
Nineteen Seventy-Seven estimates for Florida indicate that the
7-County total is 1,261,868, a seven year gain of 27 4% The
region accounts for 14.5% of the total 1977 Florida population
of 8,717,334. It also accounted for 14.1% of the state's
estimated population increase during the period 1970-77.
Future projections of regional population for the year 2000 range
from a low of 1.7 million to a high of 2.2 million.
This forecast increase in population can be easily assimulated
in the developed urban areas that presently exist within the
7-county region. Urban areas where future growth may be expected
to locate are further discussed in Section 5.3 Land Use.
Number of Inhabitants - Manatee County - The county had a 1970
population of 97,115, a 40% gain over I960. Manatee County had
count PT£ ?U?Vf 123'506' a 27% §ain over the 1970 Census
count. The 1977 figure was 129,313.
Migration has been the primary cause of county growth over the
past four decades and there is no reason for this to change in
the near future. The county will be connected to the interstate
-------
system within five years, several major industrial firms are
building large plants in the county resulting in some 2000 new
manufacturing jobs, and the historic factor of retirees locating
on the Florida Gulf coast is expected to continue.
Future population of Manatee County is projected to nearly double
during the period 1975 to 2000, going from 123,500 to 2*1,600
according to University of Florida estimates. U.S. Department
of Commerce projection for the year 2000 number 253,600 and the
Tampa Bay Regional Planning Council figure is 291,823.
Age : The age of inhabitants is a useful indicator of
socioeconomic patterns The older resident has long been a major
factor of Florida population trends. Few of the State's 67
counties are similar to the national pattern. This is a result
of retiree migration to the state. Only Hi 1 1 sborough in the
If~C9*nny r£gl°; aPProximates the 1970 median age for the nation
ol 28.0. Manatee County is representative of many of Florida's
retiree population centers. At the time of the 1970 census
nearly one third of its residents were over age 65. The county's
median age was 48. 7.
The aging trend of many Florida counties can be expected to
continue as the retiree migration continues. Factors that mav
lower average age characteristics in selected areas include:
increased industrialization or major tourism facilities which
will attract a younger labor force, and continued expansion of
service and retail employment opportunities for existing
residents allowing them to stay rather than relocate because
ol the lack of job opportunities.
Employment - The region with a population of 1.2 million has
a labor force estimated at 531,500 or equal to 45% of its
residents, thus counting some 493,000 persons working in mid-
1977. Unemployment rates range from 5-7% for each of the seven
counties in the region.
The region's employment base is quite diversified with
agriculture, food processing, light and heavy industry, retailing
and services located in the interior counties. The coastal areas
contain resort and leisure services, retailing as wen as al?
evels of industry and manufacturing, residential construction
nH™^1". fa!rt01: in unemPl°yment during periods of recession),
and substantial numbers of workers in communications, government
transportation and utilities. & '
Impact
Reg_ion - Population characteristics and projected growth for
the 7-county region should not be impacted by the planned Duette
mining operation. It is an extension of general mfntng
" * -placement fo? an
The location of the new mining operation is in a rural location
and wil not disrupt any urban activities or development w?th°n
the region. Support facilities are located in Hi ll Borough
144
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Polk counties to the north and can readily serve the Duette
site.
During construction phases, it is generally quite easy to attract
workers who are skilled in assembling industrial facilities from
within the greater Lakeland-Tampa industrial work force. The
actual number is under 500 and only for a short period.
Operation of the new Duette mine will require 324 workers
according to the DRI Application. Many of these will be
relocated Swift employees. A certain amount can be expected
from other mines and also from the local Manatee labor force.
Manatee County - The local situation is similar to the brief
Regional analysis. Needed mine workers should be easily obtained
from the local labor supply. Support workers serving the mine
operation may reside in Manatee but in small numbers.
The local labor force numbered 55,000 according to March, 1979,
state figures. As county population grows over the next 25 years
so will its employee base. Other new industries locating in
Manatee during 1979-81 may suffer a tight labor market for
production and manufacturing skills but these conditions are
believed different from the needs projected by the Swift
operat i on.
Mitigating Measures
The proposed mine will not yield adverse demographic impacts
that will require mitigation.
5. 2 ECONOMICS
An important feature of the regional economy is its diversity.
Within this 7-county region are: beach resorts, celery farming,
cattle ranching, citrus groves, deep water seaports, shipyards,
an international airport, wholesale warehousing, a steel mill,
breweries, and distilleries, small and large manufacturing
facilities, several universities, a medical school, towns of
under 3,000 population and a metro city of nearly half a
mi 11i on.
Baseline
Of the seven counties making up the central Florida phosphate
region in the Areawide study, three currently now have phosphate
mining activity with two more planning for such activity.
Charlotte and Sarasota counties were included in the Areawide
study because they adjoin phosphate operations and may become
impacted by changes in air quality, ground-water consumption
and accidental discharges of waste water into a major river and
estuary system.
In Central Florida, the phosphate industry employs some 8,000
workers with a payroll of over $110 million and pays nearly $10
million in property taxes.
145
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Income Levels and Distribution - Florida
community.
vi
oriented
of
highest
an
in the middle with a rate of 35%
figure is 37.9%.
). Manatee Bounty is
Overall for the state, the
Table 5.2-A Regional Employment by Industry, 1970 and
50-59
60-67
70-89
90-97
Agriculture,
Mi ni ng
Constructi on
Manufactur i ng
Transportation, Communications,
Electric, Gas & Sanitary Services
Wholesale and Retail Trade
Finance, Insurance & Real Estate
Services and Miscel1aneous
Government
Source: Planning/Marketing Services, Inc.
6.4
26.4
5.2
15.5
17.6
100.0%
6.4
27.7
6. 1
18.6
17.0
100.0%
near,y equal to
5'8%
Tab.e ,.2-B
Civiiian Labor Force, 1977 - 7-Cour,ty Region
Char 1otte
DeSoto
Hardee
Hi 11sborough
Manatee
Polk
Sarasota
Regi on
Source: Florida
Populati on
(July, 1977)
44,313
17,973
17,407
602,667
129,313
279,574
170,621
1, 261,868
L Stati stical
Labor
(March
127834
5,485
7,042
280,338
48,774
120,228
56,848
532,549
Abstract
Force
i 1977)
% pop.
29.0
30.5
40.5
46.5
37. 7
43.0
33.3
42. 1%
1977
Unemployment
(March, 1977)
7.2%
6.8
4.5
7.6
7.2
6.8
6.0
7. 1%
146
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Projection of the regional labor force over the next several
decades is derived from previous population estimates.
Table 5.2-C Civilian Labor Force Projections, 1980-2000
1980 1985 1990 2000~
7-County Population 1,461,600 1,654,900 1,827,200 2,152,200
Region Labor Force 613,900 695,000 749,100 860,900
% 42.0 42.0 41.0 40.0
Manatee Population 150,600 176,300 200,000 241,600
County Labor Force 57,900 67,000 75,000 89,400
% 38.5 38.0 37.5 37.0
Source: University of Florida
Planning/Marketing Services, Inc.
In Table 5.2-C, both the region and Manatee County are down-
trending in the percentage of the over age 16 population. In
actual numbers over the period 1980-2000, the regional labor
force will gain by 40.2% and Manatee by 54.4%.
Manatee County had total employment estimated at 52,300 in March
1979 from state figures. The unemployment rate was 4.9%, down
from 6.0% in March 1978.
In Manatee County the worker/population ratio was 27% in 1960
and down to 22% in 1970 for non-agricultural employment. The
county has long been a retiree corrmunity. This trend will
continue but there is expected to be an increasing demand for
major shopping facilities, new services, more utilities,
government services and industrial expansion.
Future employment opportunities in Manatee County are primarily
a continuing relationship with population gains. Only
manufacturing or industrial development can occur without normal
Florida growth. Manatee is unique, in that it has a deepwater
port, large industrial zoned acreage tracts available, an
interstate highway linkage to major markets and the Tampa Bav
labor force. J
Tax Structure - Property taxes are the primary source of revenue
to local government in Florida making up 85% of local income,
while the general sales tax is the richest income producer for
the state, amounting to 42% of Florida revenues in FY 1976-77.
Other sources of revenue available to local government include;
intergovernmental transfer of revenues, revenue sharing, fees
and licenses, utility revenues, sales tax, resort tax, fines
and interest.
The state obtains an additional 31% of its revenue from selective
sales taxes; motor fuels, alcoholic beverages, tobacco products,
iparamutual wagering, etc. Another 11% comes from licenses
The remaining sources include: corporate income taxes, property
taxes, document taxes, severance taxes and others.
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Of primary interest are those governmental revenues collected
from ad valorem and severance taxes.
Ad_yal_orem Taxes - Within the region, local property appraisers
assess rural lands at the lowest possible value under the law.
In most cases rangeland, or poor unimproved pasture, is valued
at less than $70/acre.
For the Swift property, assessment is based on agricultural uses
according to a 1971 agreement with the county. The 10,394 acre
S KvlI?Qr-,orai^°rtheaSt Manatee County was assessed at $1,802,000
tu,FV :• Thls aSSeSSGd value equaled $173/acre and was more
than four times the assessed value of comparable unimproved
rangeland surrounding the property. This agreement will probably
continue until the land is permitted for mining or a different
method of assessment is established.
Severance Taxes - Florida is one of 29 states that have this
type of tax. The current rate of tax is levied at 10% with 25%
of the proceeds available to the mining company for required
reclamation operations. In 1976, the tax produced $9.8 million
n^r^L^ ^ StatC at a 5% levy' The new tax^g formula
(1977) doubled the rate, but also increased the amount available
to be returned to the mining company for reclamation. There
is to be another change in 1980 to a levy of 8%. During the
period 1971-77 the state collected some $59 million in severance
taxes and refunded $24 million to mining companies for
reclamation.
Qther Taxes - In addition, the industry pays substantial sales
taxes on the retail sales of the phosphate rock as feed stock
to agricultural chemical products. Again sales taxes are paid
on the purchase of operating supplies and materials. Sales tax
revenues from the industry totaled $13.8 million in 1977
according to the Florida Phosphate Council.
Impact^
The proposed Swift mining operation is intended to replace
existing operations in Polk County with a new facility located
in Manatee County. As the older mine ceases production the
new Duette Mine is planned to come on stream to maintain a
continuous source of feedstock for Swift operations in Florida
into the 21st century.
The proposed mining activity approximates a 30-year time period.
This includes: site preparation, plant construction, mine
operation and reclamation. Total expenditures for the proposed
mining activity will approximate $647 million in capital and
operating costs (Swift Agricultural Chemicals Corporation^ 1978).
The following sections will address the economic impacts of the
Swift mining operation on the Central Florida phosphate study
region and also upon Manatee County. Costs and values are in
constant 1978 dollars except where noted.
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Dil££l_§flects. - Direct economic effects are measured relatively
easily. They will be substantial outlays in capital and labor
during construction and operation. The new Duette mi nine
operation will have a stabilizing effect on the 7-county region
as employment and expenditures are maintained for an
additional ± 30 years. Without the facility, the region would
suffer an opportunity loss as the existing operat i on^eases and
Swift would be unable to replace the facility.
The proposed activity's impact on the regionl economy is small
of 605 Inn thrT°?+1S Pr°Jected to achieve a 1990 employment
?Ln ' ~, Duettemine 324 or equal to 3.2% of projected
1990 regional mining employment of 9,983. Annual production
is estimated to be 3 million short tons per year - 6.7% of the
projected regional figure of 44.8 million tons in 1990.
Local impacts are several. Polk County is going to lose its
Swift mining operation as the ore body runs out. Manatee County
can gain substantial tax advantages and possibly over 100 new
jobs. It is assumed that over 200 workers will corrmute from
the existing Swift labor force in Polk County. Non-use of the
mine site would tend to retain the poor rangeland land uses in
the eastern county with resultant lower tax payments to local
government.
Local and state tax collections are also a direct effect of new
economic activity. The new mining activity will create real
property investment in Manatee County that will pay substantial
local real estate taxes. Purchases of supplies and installation
of new equipment are also taxable. IMJ, tai lanon
The following figures are the projected primary direct tax
revenues to state and local government during mining operations-
Sales Tax (State) Annual Yield
operating supplies <3c materials
value - $9,561,000 x 4% - $ 382,400
Severance Tax (State)
Value to be set by Dept. of Revenue
est. value - $16.00/short ton,
tax rate (1980) 8%
25% of revenues - returned to
mine for reclamation
25% of revenues - to Fla. phosphate
Research Inst.
50% or revenues - to state general
revenues
production 3,000,000 T.P.Y. x $16.00 =
$48,000,000 x 8% = $3,840,000 - 50% = $1,920,000
Ad Valorem Tax (County)
value of real estate and plant
$120,947,400 x 16.388 mills = $1,982,000
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These are the primary revenue items to be analyzed. Additional
taxable sources are included in the multipliers presented as
indirect and induced effects on the region. Impacts on the
national economy are beyond the scope of this work and have been
presented in the recent Areawide study of the Central Florida
phosphate industry.
The following additional direct effects to Manatee County should
be meas ur eabl e :
Agriculture - A small grove would be cleared, rangeland improved
through reclamation for an annual gain in productivity of
>j c. -/ U j f U U •
Housing - No housing will be displaced on the site. A portion
of mining employment is expected to reside in Manatee County.
Some will be relocating from Polk County, probably the majority
will be current Manatee residents. New households could number
50, at an average home purchase of $40,000 each this could total
$2 million in investments in the early years of operations.
Employment - An estimated 100 of the mine's 324 employees will
reside in the county. Total payrolls and subcontractor labor
costs are projected to total over $39 million over the life of
the mine. The annual operating payroll for Manatee residents
is approximately $1.5 million.
Business - Local wholesalers, servicemen and repair facilities
should furnish a portion of the mines total maintenance and
supply needs. This is estimated to amount to $1.8 million
annual 1y.
Government Services - The proposed activity should have only
a light impact on typical local government services. It will
absorb up to 100 local employees but with little impact or demand
lor public facilities such as roads, parks or schools. The
mine operation itself is in a remote rural area and is self-
sufficient in public utilities, security, fire and safety.
Local Taxes - The County tax base would increse greatly with
the proposed activity. In 1976, the 10,394 acre site had an
assessed value of $1.7 million and yielded ad valorem taxes of
$28,137 at the rate of 16.388 mills to Manatee County according
to the DRI Application. With capital improvements completed,
the DRI estimates the following annual ad valorem tax yield
during mining operations:
Yield
6624 acres - mineable land
@ $800/acre x 16.388 mills $ 86,843
3769 acres - unmineable land
@ $172/acre x 16.388 mills 10,624
Value of plant
@ $115,000,000 x 16.388 mills 1,884,620
Total ad valorem tax yield per year $1,982,087
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Indirect/Induced Effects - The previous figures can be expanded
to include the indirect and induced effects of the proposed
activity through input/output analysis. The recent BOM study
°fthe
, Significance of the Florida Phnsnhat* Industry
de ineates i nter i ndustr y mul t i pi i er s that can be used to further
illustrate impacts on the regional economy. It should be
recognized that impact estimates are used to reveal magnitude
and are not necessarily an accurate or preci se measurement .
Based on pro j ec ted mi ne production figures of 3 million short
tons/year (2,720 million metric tons) and a $24. 00/met r i c ton
value at the mine, annual production could total some $65 3
million in sales (using constant 1978 dollars) or direct output.
The indirect output effect includes purchases of other goods
and services for the operation and in addition sales of various
levels of suppliers to the industry must be figured To this
should be added the induced impacts of wages arid salaries o
mine workers and suppliers. The following figure illustrates
an average production year:
Direct impact $ 65. 3 million
Indirect impact 35.4
Induced impact 1 18. 9
Total impact $219. 6 mi 1 1 i on
Estimated employment associated with the proposed activity are
projected in a similar manner using BOM mul t i pi i er s for an
average year of production:
Direct impact 324 employees
Indirect impact 235
Induced impact 1425
1994 employees
The analytical process of developing input/output mul t i pi i ers
at the local level is questionable. For that reason much of
of effect! imPaCt 3SSeSSment is oriented towards a direct measure
Mitigating Measures
beendentifdh r e^ui r * "g mi ^ g*t i ve measures have
been identified. The economic impacts generated by the proposed
project have a favorable effect upon the area. proposed
5.3 LAND USE
The study area delineated in this survey element embraces the
7-county region as described in Sections 5.1 and 5.2
Basel ine
Current Regional Land Use - Land use activities in the 7-county
5500 square mile region are primarily agrarian in nature with
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urban development occurring along Gulf and Bay coast lines in
Charlotte, Hi 11sborough, Manatee and Sarasota counties. The
interior of the region houses smaller communities astride long
established north-south railroad or highway routes. The lone
exception being the city of Lakeland, an important commercial
center located in Polk County.
recent USGS Land Use Survey only 9.3% of the 7-county
:asured as "Urban or built up" in 1975. This amounts
Based on a
area was measi _
to 520 square miles, housing an estimated population of [.2
million.
Nearly 63% was listed as crops, pasture, groves, and rangeland
while barren land including mining operations totaled only 6%
of the study area. The remaining 22% was forest, wetland and
water.
Manatee County - The county is presently dominated by open space
land uses. Rangeland and agricultural uses made up approximately
75% of the county in 1975. More intense land uses described
as urban build-up within the Areawide EIS, accounted for only
7.67% of the county in 1975 and were located predominately in
the area irrmediately around the communities of Bradenton and
Palmetto, and on Anna Maria Island and Longboat Key.
There are three predominant catalysts for land use change and
development in Manatee County which can be expected to continue
present trends. The most significant is the coastal geography
of the county which is attractive to urban uses such as
residential, commercial, and industrial development. The coastal
area can be expected to remain the dominant locus for future
growth. The second catalyst is existing and planned highways,
which act as a spine for the growth areas of the county. And
the third is the natural resources that exist in the form of
phosphate deposits and wi 1 1 attract the mining industry.
Residential and other urban uses can be expected to increase
proportionately to population growth. The county is projected
to nearly double in population by the year 2000: going from
123,500 to 2*1,600 in twenty-five years.
Future Regional Land Use - Typically, agricultural land uses
are reduced as urban encroachment occurs. Main losses of
economic importance in the 7-county region are some 22,000 acres
of orchards and groves, primarily in Hi 11sborough, Manatee and
Polk counties. Considerable amounts of pasture and rangeland
will also be removed from agricultural usage during the period
1975-2000 by mining operations. Much of this displacement will
be temporary as reclamation of mined lands will return much of
the former agricultural land to productive uses.
Urban development is projected to total approximately 500,000
acres by the year 2000. This is a 43% increase over 1975 but
amounts to 13% of the total regional land area.
It is generally forecast by business and government planners
that future urbanization of West Central Florida will expand
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around existing centers of population and t ranspor tat i on routes
This is true for the region as well as Manatee County.
Impact
acres that make UP the Swift Dining site represent
0.3% of the 7-county region. The majority of the site
approximately 78%, consists of unimproved agricultural land and
rangeland with poor soil conditions.
The site is proposed for agricultural use in the Manatee County
Comprehensive Plan, which is consistent with the planned mining
operation because of the proposed land reclamation program.
The geographic location of the Duette Mine, in the northeast
corner of Manatee County, gives it a central position within
the region, and tends to lessen its impact upon urban Manatee
County. In addition, the existing highways allow the mine to
be served equally by the built-up areas of Polk County, to the
north along SR 37, as well as Manatee County to the west along
SR 62. SR 62 also puts the built-up areas of Hardee County
within reach. 3
It is anticipated that many of the mine workers will have been
employed at other mines within the region. Experience with other
mine operations adjacent to the site indicates that the built-up
areas of Bartow, Mulberry, Ruskin, Parrish, Myakka City, Palmetto
and Bradenton are sufficiently close to serve the residential
needs of mine employees. Because of this, no new built-up areas
or significant expansion of existing built-up areas will be
attributable to the mine.
The proposed action will not significantly affect the future
growth patterns within the built-up coastal areas of Manatee
County. The anticipated growth in residential land use will
remain in and around existing built-up areas throughout the 20
year life of the mine operation. The comnercial and
institutional land uses generally associated with residential
development will also develop where they are presently
concentrated.
The mine site is principally made up of agriculture, forest,
wetland, rangeland and barren land. The mine would largely
Unimproved ran§eland, which made up 47.4% of the County
Agricultural land would be significantly increased by the mining
process. This is attributable to creation of improved pasture
land once the disturbed land is reclaimed. Approximately 5516
acres of agricultural land would be gained by the region.
The end result of the Swift mining operation on the county would
be a net improvement in agricultural land uses.
Mitigating Measures
All necessary mitigating measures for land use wi 1 1 be provided
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for through the reclamation process described in detail in the
Reclamation Methodology Resource Document. No significant
adverse impacts on land use requiring additional mitigating
measures have been identified.
5.* COMMUNITY SERVICES AND FACILITIES
Baseli ne
Regional Facilities - The 7-County Region contains a variety
of community facilities: Water supply, solid waste removal,
electricity supply, transportation systems, medical facilities,
schools, parks, recreation facilities, police and fire
protection. The majority of the built-up or urban area of the
region is served by facilities operated on a local or county
level. The regional scale facilities tend to serve more than
one locality and cross county lines. Such facilities include
the highway system, railroad lines, electricity supply and
certain law enforcement and recreation facilities. Section 5.6
addresses the local and regional highway system and railroad
1i nes.
Facilities Within Manatee County - Community facilities provided
on a local and county level include governmental administration,
law enforcement, fire protection, public water supply, waste
disposal, health care, recreation and education.
Without the proposed action, the majority of the facilities cited
would continue to serve the population within the built-up areas
of the county.
Impact
Region - The Duette Mine operation is to replace production by
a mine scheduled to be phased out of production. The impact
on regional community facilities will be absorbed by the
decreasing demands of the former mine.
Electricity is a major element of phosphate processing. The
proposed mine would be served by the Parrish Plant of Florida
Power & Light Company System, however, other companies serving
the region could augment the Parrish Plant when necessary. Upon
completion of mining operations in 20 years, generating capacity
will be available to serve the projected population growth that
will locate in the region.
The highways that serve the region will be sufficient to serve
the trips generated by the Duette Mine personnel. Very little
traffic other than personnel trips to and from work is
anticipated. Ore material will be moved by railroad.
Improvements and extensions to existing lines will be made to
serve the requirement of the Duette mine and other mines in the
region. Section 5.6 discusses transportation in more detail.
Other regional community facilities largely serve the residential
population base and can be expected to be expanded upon through
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general population growth pressures. The 300 personnel employed
by the mine will not affect the demand for services.
Manatee County - Manatee County and local jurisdictions provide
corrmunity facilities which are not of a regional scale. Such
facilities generally serve the built-up area of the County where
the population can be expected to be concentrated within future
years .
The Duette Mine is not expected to have a significant effect
upon potable water supplies within the County. Fire protection
and law enforcement facilities largely serve the built-up area
and there is no reason to anticipate any increased service as
a result of the proposed mine. Fire protection and emergency
medical services will be provided on the mine site. Domestic
waste generated by the mine will be treated on-site. Industrial
wastes will be recycled during the mine reclamation process.
The health, education and recreation facilities within the County
are not expected to receive a significant impact because they
are directly related to the growth in population. Manatee County
currently provides an acceptable level of public facilities and
services by public and private support. Most services are based
on population or market demand and increase annually with
growth. The small population generated by the proposed mine
will be dispersed over several residential areas, and only a
portion will be in Manatee County. Therefore, minimal impact
will be perceived in the county.
Mitigating Measures
No adverse impacts requiring mitigating measures have been
i dent ifi ed
5.5 SENSITIVE MANMADE AREAS
Baseli ne
The intent of this element is to identify those manmade areas
or features that are susceptible to being adversely impacted
by the proposed activity.
Typically for a mining operation this might include: residential
areas or even small cities or towns and other urban development-
transportation systems, roads, airports, railroads, ports: and
rural development of farms, nurseries, feedlots, ranches, and
other intense agricultural uses.
The Duette Area - Section 5.3 Land Use addressed general
characteristics of land development within the 7-county region
and more specifically Manatee County where the proposed mining
activity will occur. &
Presently, only a few manmade features are to be observed within
the rural Duette area. They include three state highways and
the county road connecting SR 62 with SR 64 to the south.
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Numerous private roads serve area individual homes and ranches.
Residential development includes some 30-40 dwellings within
two miles distance of the proposed mining operation. Several
are located in the old settlement of Keentown, an out-parcel
in the center of the mine site. A few more are on SR 62 near the
5R 37 intersection and the Duette School. Another scattered
cluster of housing is west of the mine site near the Bunker Hill
church.
Other urban features include the Duette elementary school, the
county's only one-room school house, a small country church,
two small cemeteries and a utility substation. Rural manmade
features include: fencing, drainageways, farm buildings and
structures, planted crops, groves and forests.
Section 5.7 will identify and discuss certain archaeological
and historic sites located within the mine site area. There
are no historic sites or structures of sufficient significance
to meet the National Register of Historic Places criteria. A
single prehistoric site does meet the significance criteria and
is recommended for preservation or archaeological excavation.
Impact
The primary impact of a surface mining operation on any on-site
manmade feature would be its total removal by site clearing.
Secondary impacts are those environmental conditions that might
change because of mining and processing that would effect human
habitation and public facilities. These might include: increased
noise levels, air pollutants, or increased vehicle traffic on
1 oca 1 roads.
Primary Impacts - No existing families will be displaced by mine
operations. Several old homesites and prehistoric sites will
be removed by mining operations. A prehistoric site which meets
National Register criteria is recommended for protection.
Secondary Impacts - The local highway and road system will
witness increasing vehical trips during mine operations. Section
5.6 addresses this issue and indicates that projected traffic
is light and would not have a negative impact on road
conditions.
Other secondary impacts on nearby residents, the school and
church will be increased noise levels when mining operations
are located close by. Wind blown soil may also be a nuisance
to nearby residents, but should be controllable through proper
clearing and revegetative techniques.
Another source of fugitive emissions will be the drying operation
and railroad car loading. Abatement measures are required and
the site is well inside the property and over a mile from any
residence. *
Existing agricultural activities adjacent to the proposed mining
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activity should not be impacted by Swift operations other than
a potential for ground and surface water changes in volume or
flow. This is addressed in the appropriate section of the EIS.
Agriculture land uses on-site undergo a significant positive
economic change as rangeland is mined, reclaimed and then turned
into improved pasture or seasonal crop lands.
Mitigating Measures
Adverse impacts and their associated mitigative measures for
cultural resources, transportation, and air quality have been
examined in their respective sections. No additional adverse
impacts requiring mitigating measures have been identified.
5.6 TRANSPORTATION
Baseli ne
Roads - The road network in the primary impact area of the
proposed Swift Duette Mine is shown on Figure 5.6-1.
All thoroughfares with the exception of Duette Road are state
roads. All state roads are twenty-four foot wide, paved,
undivided, rural sections.
The only planned improvements to the road network in the primary
impact area is the extension of State Road 39 to the south, to
connect to State Road 64.
Table 5.6-A gives the latest F.D.O.T. twenty-four hour average
daily traffic counts for the road network adjacent to the
proposed mine site.
Future traffic flows without the proposed mine are also shown
in Table 5.6-A. The 1977 F.D.O.T. counts were used as a base,
and traffic flows were projected to the year 2000. An 8% growth
factor was assumed.
Table 5.6-A Project Highway Traffic Without Proposed Mine
Locat ion
1977
1980
1990
2000
Stat
Stat
(wes
e
e
t
Road
Road
of SR
39
62
37)
1
1
119
694
1
2
410
071
3044
4471
6572
9653
State Road 62
(east of SR 37) 1372 1728 3731 8055
State Road 37 1129 1422 3070 6628
As per the "Highway Capacity Manual, 1965" published by the
Transportation Research Board, Washington, D.C., service level
"A" exists during the peak hour on all roadways within the
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UJ
(Jl
FIGURE • 5.6 - I
EXISTING TRANSPORTATION NETWORK
SOURCE • CIVIL ENGINEERING CONSULTANTS , INC.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION
PROPOSED DUETTE MINE
MANATEE COUNTY . FLORIDA
158
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primary impact area.
Rai1 roads - The existing rai
by the proposed Swift Duette ivillic, is snown on Figure s c. 9
Seaboard Coast Line Railroad supplies the fre? ^ 5-6-2.
the study area and throughout most of the state Service ln
"he" ™jSr Hy of ' r^U "ra^fi Ho ^T"3 ' * '^'^
The Lakeland terminal is somewhat smaller and handles
pnuspnate by-products according g^erai freight and some
plan; Products according to the previously cited rail
cars per day.
tonJw^et^en'ISSo1^1^^ ^ frcdicts a 5°% in<™ -
create the demand fnr zuuy- Resultant total tonnages will
* ^•*-*-''o^/|jioxi nrici tGlv 1500 f^si*Q ^n o ^-i-^'i L
moving phosphate into Port Tampa, in the yJar 2000. * '
- Port Tampa and Port Manatee by their geographical
will probably handle the majority of phosphate generated
Port Manatee is located as shown on Figure 56? ™ * -,-
began operations in 1970 and is capabl! of hanrffi facility
-- Ly H
'
r
Manatee and Tampa shoufd be comol ted J ?" between northern
the mid 1980's. completed sometime thereafter in
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> m 3
O 7n C
i *
m r~
z v>
m i^
1 O
(7)
m
pi
in
i
IV)
w
C/)
H
m
? S 5
P^S:
§iii
> H Z O
"" i Z
_sr.
-------
Impact
Roads - The road network shown in Figure 5.6-1 is the primary
impact area and this area will undergo an increase in vehicular
traffic due to the proposed mining operation. The initial
increase will be due to the construction of the plant site,
whereas later increases in traffic will be due to the daily
operation of the mine itself. Traffic generation from the Beker
and Grace proposed mines has been considered in this analysis.
Based upon an average employment of approximately 450
construction workers during the two-year construction phase,
1170 trips per day will be generated. Eighteen to twenty percent
of those trips will be truck traffic. The a.m. arrival and
p.m. departure of the workers will create the peak hour periods
of vehicular activity. The peak hour volume will be
approximately 500 trips per hour.
The effect of the construction phase traffic will not cause a
significant impact upon the road network shown in Figure 5.6-1.
The mining operation will generate approximately 1630 trips per
twenty-four hour period.
The major peak hour will occur when maintenance and dragline
crews change shifts between 6:30 and 7:30 a.m. It is anticipated
that 190 trips will be generated during that hour.
Traffic generated by the Swift Duette Mine will not have a
significant impact on the thoroughfares within the primary impact
area. Service Level "A" (Free Flow) will be maintained through
1985. However, the normal traffic growth expected after that
period will cause a decrease in service levels by 1990 (Table
5.6-A). Service Level "B" is expected on all extended sections
of state roads by 1990, and Level "C" will be developed by 2000.
These levels will occur during the peak hour of mine operation.
The state road intersections (i.e., S.R. 62 at S.R. 39, S.R.
62 at S.R. 37) will operate at lower levels of service than the
extended road sections. Should these intersections remain
geometrically unchanged, Service Level "C" will occur by 1980
during the major peak hour. By 1990, service levels will decline
to "D", and by 2000 these intersections will be at capacity.
After peak periods, these intersections will operate at Service
Level "C" or better through 2000. The lowering of service levels
is a significant negative impact.
Duette Road will be the only entrance to the plant site.
Consequently, it will undergo the most severe effect. However,
the road will still operate at Service Level "B" or higher
through 2000.
There is no existing railroad spur that could serve the proposed
site. The possibility that no railroad will be built is very
remote, especially when there are two mines already approved
by Manatee County in the irrrriediate area (i.e., Beker Phosphate
and W. R. Grace and Company). Should the estimated three million
tons per year of phosphate ore be transported by truck, it would
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create a significant negative impact on the road network in the
primary impact area, and on the road network adjacent to the
near by seaport s.
Rai1 roads - The proposed mining operation will generate one
hundred, 80-ton rail cars per day. Approximately 80% of that
traffic will go to a seaport. Should a rail system be
constructed to the Swift Mine, it will be able to transport the
ore using the "Unit Train Method" now being used by mining
operations in Polk and Hillsborough Counties. This method
theoretically gives a railway system an infinite capacity.
The constraints on such a system are not the capacity of the
rail line, but the capacity of the loading and unloading
facilities, and the storage capacity at the Port destination.
The availability of cars and locomotives is also a limiting
factor. The addition of 100 rail cars on this system will create
a negative impact on the rail system.
The rail system serving Port Manatee is in its early stages and
basically has no capacity problems. The increased traffic from
the proposed mine would not have a significant impact, assuming
a suitable bulk loading facility was constructed at the Port,
with adequate storage capability.
For ts - Three million tons of phosphate ore will be produced
per year by the proposed Swift Duette Mine.
Presently, the Port of Tampa has the only major bulk loading
facilities capable of handling the anticipated production from
the proposed mine. The existing loading facilities will have
the ability to handle the mine output without any significant
adverse impacts. However, due to the lack of storage facilities,
rail cars, and traffic congestion on U.S. 41 caused by the
shipment of phosphate ore, it is apparent that there will be
a significant negative impact on the Port of Tampa area as a
whole from the movement of the projected three million tons per
year .
Should Port Manatee construct a major bulk loading facility,
the Swift Duette Mine project would create a very significant
beneficial impact on those facilities and the Port area in
general.
Mitigating Measures
Roads - The recommended modifications at intersection of S.R.
62 and Duette Road would include widening to incorporate turning
lanes and possibly signalization.
Railroads and Ports - As a general overview, the construction
of a railroad line directly to Port Manatee, should the Port
develop a major loading facility, would be the most profound
mitigative measure. Increased rail traffic would not impact
the congested Port of Tampa railway network and would prevent
further burdening of the Port of Tampa storage facilities and
Port traffic circulation.
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5.7 ARCHAEOLOGICAL AND HISTORICAL PROPERTIES
Basel 1ne
Two field surveys of the Duette Mine tract were undertaken to
locate historic and prehistoric cultural resources on the
property, to evalu?.te the significance of the resources, to
determine impact on the resources and to recorrmend mitigative
measures. The first survey was carried out in December 1974
(Ecolmpact, 1974) as part of a Development of Regional Impact
report. The second survey was designed as a test of the prior
work and was conducted as part of the investigation in
preparation for the present Environmental Impact Statement
(Grange and Williams, 1978). Details and documentation of these
surveys may be found in their respective resource documents.
Although there are many ecological zones within the region, many
formulations view the area as having two major zones--a coastal
strip and an interior hinterland. These two major zones are
connected by streams and rivers flowing from headwaters in the
interior toward the coast. The interior or "hinterland" region
contrasts with the coastal zone in resources. It lacks the
abundant shellfish which support more dense prehistoric
populations on the coast. The poorly drained pine, flatwood
and swampy interior has often been interpreted as a hunting
area. Although hinterland uti1ization models developed by
earlier archaeological work are not fully supported by present
data, prehistoric population density was much heavier in the
coastal area than in the hinterland.
The Duette Mine is within the Manatee Archaeological Region,
but is close to the boundary of the Central Gulf Coast Region
and Glades Region and cultural influences from both of these
spatial units affect the area. Paleo Indian sites (circa 12,000-
8000 B.C.) are primarily found along the coast and in locations
drowned by rising sea levels. Early Archaic Period sites may
also be inundated. Late Archaic sites, dating after 5000 B.C.
have been found throughout the region around the Duette Mine.
Many sites attributed to this period are lithic scatters lacking
the diagnostic projectile points. By the close of the Archaic
Period, about 2000 B.C., sea level had approximated its modern
level and associated landform, flora, and fauna of today were
similar to those utilized in the past.
The Orange Period is defined by the introduction of ceramics
and about 1000 B.C. Deptford pottery appears in the Central Gulf
Coast Region. Sand tempered ceramics from the Glades area to
the south are also present in the sites in the Manatee Region.
Burial mounds appear in this period. A few mounds are found
in the interior hinterlands and such features may represent
significant cultural resources. Later sedentary peoples in the
area are represented by the Perico Island and Weeden Island/Santa
Rosa-Swift Creek Periods between 500 B.C. and A.D. 1300. These
periods may also be represented in the Duette Mine tract, since
Weeden Island mounds have been found on adjacent property. The
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focus of settlement remains on the coast during these periods
and in the succeeding Safety Harbor Period of A.D. 1300 to 1700.
Safety Harbor sites are also present in the interior areas and
form the basis for the now modified hinterland hypothesis.
Spanish exploration of the sixteenth century, as well as later
Euro-American activities, were largely focused on the coastal
area and the lower reaches of the Manatee River which has its
headwaters in the Duette Mine tract.
American settlement of the area came after initial land surveys
in 1843. The Duette Mine area was mostly patented to the State
of Florida in 1856 or later. Homesteading of sites adjacent
to, but not on, the mine tract occurred in 1878 although cattle
may have been run in this area during the Civil War Period.
Most of the Duette Mine tract was deeded to the Florida Southern
Railroad Company in 1883, although a small area was included
in the Disston Purchase in 1883. There were only limited
individual land holdings in the mine tract in the 1880's.
Most of the property was utilized for ranching purposes, with
associated pasture improvement operations. Field survey of
homestead locations on the property revealed no standing
structures and the remains of collapsed buildings were all wire-
nail constructed and thus probably post-date 1891.
jmpact
Historic Period Sites - The criteria for determining significance
of historic sites is stated in 36 CFR 800.10 "Procedures for
the Protection of Historic and Cultural Properties".
The Duette Mine tract area played a part in the agricultural
development of Manatee County. However, the historical review
of the general events and specific individuals and companies
involved in the settlement process revealed no historical
reference to individuals, events, sites, or structures of
sufficient significance to qualify an associated site for
National Register status. There are, then, no historic period
sites which meet National Register criteria on the property.
Thus, although some historical period homestead loci will be
destroyed by mining operations, these impacts will not adversely
affect regional historical resources.
A total of five prehistoric sites were located on the property
during the course of the two field surveys. The work in
preparation for the EIS drew upon settlement pattern and its
relationship to ecological data gathered in earlier surveys of
similar mining tracts around the Duette site. A predictive model
was developed which allowed the identification of areas where
there was a higher probability of the presence of archaeological
sites. These areas are within 2000 feet of permanent water
(e.g., the streams on the property), within 4000 feet of a
hardwood hammock and on the better drained soils within these
parameters. All three sites on the Duette Mine tract located
in the Ecolmpact survey were within the expected locations.
The Ecolmpact survey investigated the entire mine tract. As
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a further test, a sample of 30% of the high probability area
was resurveyed by the EIS team and two additional prehistoric
sites were located, both within the expected zone (Figure 5.7-
1). Both sites were iithic scatters marked by two chert flakes
at each site.
Figure 5.7-1
Archaeological and Historical Sites
Probability and Location Map
Thus, two surveys resulted in
Four were Iithic scatters and
additional mound, formerly on
ago during the development of
locating five prehistoric sites.
one was a small sand mound. An
the property, was destroyed years
an orange grove.
The Iithic scatter sites were ail very low density locations
producing only debitage from chert preparation and no diagnostic
artifacts for cultural classification. All were in-disturbed
locations where orange grove cultivation or farm roads resulted
in destruction or disturbances. Tests revealed no preserved
cultural stratigraphy or site integrity. None of these sites
meet the significance criteria of 36 CFR 800 and, although they
may be destroyed in mining operations, the impact will not result
in loss of significant archaeological data. The recorded site
location information contributes to the growing body of
information about the settlement pattern and ecological
relationships of sites in the riverine headwaters, however.
The Carruthers Mound is deemed to meet the significance criteria
on the ground that it may contain data of regional archaeological
importance. A test by Ecolmpact did not produce diagnostic
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artifacts and the site remains of unknown cultural
classification. However, mounds represent a more settled way
of life in an area which has been characterized as a "hinterland"
hunting zone and none of these mounds has been excavated by
archaeologists using modern techniques. Such sites, few in
number, are important cultural resources. The Carruthers Mound
is in an area which is not scheduled for mining and hence will
not be destroyed in that operation. It would, however, be
isolated from its former environment, which is identified as
an adverse impact since associated archaeological data may be
present in the surrounding area.
Mitigating Measures
Two mitigative alternatives exist for the Carruthers Mound,
One is to preserve the site and protect it from destruction or
damage. The DRI report for the Duette Mine proposed to
accomplish this goal by fencing the mound. It was the opinion
of Grange and Williams (1978), however, that fencing the mound
alone will not adequately protect it and its irrmediate
environment. The area surrounding the mound is considered
crucial to site interpretation. In fact, any full-scale
excavation of the mound would also require testing at least 100
meters around the mound to be considered adequate. Cultural
and natural data directly related to mound construction should
be within that distance although this is only an estimate due
to lack of data from excavated sites of this type in this area.
The second alternative, if preservation is impossible, is to
excavate the site. In this case, this should be understood to
include investigation of an area around the mound as well as
the mound itself.
5.8 RESOURCE USE
Energy - Electricity, gasoline and diesel fuel will be the energy
sources used during the construction phase of the project. Once
in operation, the mine and plant will operate on electric power
supplied by Florida Power & Light Company.
Fuel oil will be used to provide thermal energy for the product
dryers, and gasoline and diesel fuel will be used for motor
vehicles.
Average operational demand power will represent 4.4% of the
transmission line capacity, and 2.9% of the Parrish power plant
capac i ty.
Tables 5.8-A and 5.8-B show energy consumption by phase of
operation and by area during normal operations, based on
preliminary engineering estimates (Swift DRI, 1978).
Energy consumption will account for at least 20% of the total
operating costs, with increases probable in the near future due
to the ever increasing costs, utility companies must pay for
fossil or nuclear fuels. Therefore, considerable economic
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incentive is given the company to provide for maximum efficiency
and conservation of energy. The design has been reviewed for
possible mitigative efforts to reduce requirements for electric
power and fuels to minimum levels.
Table 5.8-A Energy Consumption by Phase
Phase
Cons tr uc t i on
Start-up
Oper at i on
Avg. KVA
3,000
51,800
51,800
Dryer
Fuel Oil
Gal /Day
0
12, 125
28,250
Gasol i ne
Gal /Day
500
350
350
Diesal Fuel
Gal /Day
500
350
350
Table 5.8-B Energy Consumption by Area
HorsepowerAverage Load
Area (Connected)
Mi ne
Washer
Feed Preparation
Flotat ion
Waste Distribution -
Waste Disposal
Reagent Storage -
Off si tes
Wet Rock Storage
Dryer , Load Out
TOTAL
26,501
4, 378
6,525
5,892
26, 352
648
854
2,239
73,389
17,859
3,086
4,951
4,534
18,458
562
615
1,613
51,768
Water - The existing ground and surface water systems, their
resource availability, effect of use, and conservation are
discussed in detail in separate sections of this report.
Mineral Resources - The prospecting base of 245 holes used for
reserve identification by Swift is statistically adequate to
define the property's reserve potential for planning purposes.
The stated reserves for 60 million short tons of product as
estimated by Swift are recoverable at best management practices,
considering both mine and process recovery. There is a
possibility of an expansion of the reserve by improved technology
and/or economics. The mine life could be extended by perhaps
10-25% by improvements in either of those areas. However,
assuming that this additional ore would be less concentrated,
the overall production rate, with no expansion of the processing
facilities, might decrease.
There is sufficient incentive due to reserve and development
investment for Swift to provide the practices necessary to insure
maximum recovery.
Certain portions of the property, as indicated in other sections
of this report, have been withheld from mining including portions
of the major stream courses on site and a wetlands area. Ore
underlying these areas, which may amount to several million tons
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of product, is not planned to be recovered due to regulatory
constraints governing mining in wetland areas.
The uranium content of the recovered product is estimated to
pnHI?? !i0m 5?-100 PP™' This is not as high as in some Polk
County deposits presently being exploited for both phosphate
and bi-product uranium. No current plans for downstream
extraction of the uranium from the phosphoric acid have been
identified because extraction would be performed by the consumer
01 the rock production rather than Swift.
s«-J*e P|anned 3-° million short tons of product per year rate,
Swift will deplete the deposit's presently identified recoverable
V?Lin the. Projected 21 year mine life. The 60.0 million
tons of the economic reserves represent 4. 3% of the
'tin"1 Jlorida resources having a cost of less than $20 per
o ?HP trtCCreHab e fPr°duct (Zellars-Wii liams, 1978), and
of the total identified resource.
Neither the Department of Energy at state or federal levels nor
any other agency hold regulatory authority over the use of energy
at t n i s t ime. °J
The agency charged with authorizing diversions from either ground
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6.0 COMPARISON OF PROPOSED ACTIVITY WITH
AREAWIDE EIS RECOMMENDATIONS
The Final Areawide Environmental Impact Statement for the Central
Florida Phosphate Industry published by the Environmental
Protection Agency in November 1978 evaluated the impact of
various alternative scenarios of phosphate mining in central
Florida. The EPA reconrmendat ions represent a scenario of
phosphate development which was determined to be as compatible
as practicable with other desired and intended land uses. This
scenario provides a decision making tool for all new source
phosphate mines in central Florida.
The following discussion compares the proposed activity to the
EPA reconrmendat i ons for mining and benef i ciat ion. The
reconrmendati ons and clarifying statements are underlined followed
by a description of the proposed activity.
o Eliminate the rock-drying processing at beneficiation plants
an~d transport wet (6-20% moi sture) rock to chemical plants.
Only rock to be utilized in triple superphosphate, elemental
phosphorus, def1uorinated rock feed, or other fertilizer
pTbcesses requiring dry rock would be dried - and this would
be at the chemical processing complex or at dryers permitted
by PER prior to publication of the DEIS. A possible exception
on a case-by-case basis could be made for rock to be shipped
outside of Florida for chemical processing; if the energy
for transporting the moisture were greater than the energy
saved by eliminating drying, drying at the beneficiation plant
would be considered if air quality (including radiation could
be adequately protected.
Since the Areawide EIS study was undertaken, important study
assumptions relative to air quality were mitigated by a
significant action of the U. S. Congress. The Clean Air Act
Amendments of 1977, required the application of Best Available
Control Technology (BACT) to all significant sources and source
modifications which had potential to deteriorate air quality.
The recommendation to eliminate rock drying in the Areawide EIS
was based upon greater allowable source emission rates than are
now permitted by U. S. EPA Prevention of Significant
Deterioration (PSD) Regulations promulgated under the 1977
Amendments. For example, study assumptions for particulate
matter were limited by allowable emission rates as provided for
in the Florida Administrative Code (F.A.C. 17-2.05,2, Process
Weight Table). This rule permitted particulate emissions at
least twice as great as allowed under the PSD Regulations. A
conclusion of the Areawide EIS proposed action was that the
phosphate industry pollutant contribution would remain relatively
constant after 1977. However, the PSD Regulations suggest that
the contribution should decrease as new processing facilities
are constructed and older less efficient control systems are
replaced with new technology.
By establishing maximum increments of allowable deterioration,
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the PSD Regulations effectively restrict availability of the
air resource. Once the available resource is consumed by
competing interests, no significant additional source effect
can be permitted without a corresponding reduction in effect
from another source.
Thus, the objective of the Areawide EIS to protect air quality
will be attained by an enforceable and pervasive system of air
quality controls that exert influence over all major industrial
source contributions.
Swift proposes to contruct a rock drying facility at the Duette
Mine site. Two fluidized bed dryers are planned for drying 262
tons per hour each (dry basis) of phosphate rock from 13 to 2%
mo i s t u r e.
The proposed drying facility is dictated by market conditions.
Total acceptance of wet rock, as the basic form of the phosphate
rock conmnodity on the world market, is not expected for some
time. Many users have small phosphoric acid plants and the
designs vary widely making conversion to wet rock not only
expensive, but technically difficult. Conversion to wet rock
also requires installation of wet rock grinding in addition to
major wet phosphoric acid process design changes. Significantly,
capital for the modifications is not readily available in many
developing countries.
Some dry rock is used to produce triple superphosphate for which
no wet rock process exists. If drying at the acid plant is
desired, small dryers located at small plants are inefficient
and very expensive compared to the large units employed by rock
producers.
In terms of operating costs at the mine plant site, shipping
wet rock is less expensive than drying the rock. These costs,
however, are only transferred and increased if the customer is
not capable of processing the wet rock since water must be
shipped and then removed by drying. Heavier wet rock results
in higher delivered costs at all points of delivery except the
lower Mississippi. Beyond the 1,000 mile radius, shipping costs
exceed drying costs; therefore, the competitive market ing cost
becomes a major factor. Product grade, quality, and condition
become more important in the world market and customer
specifications are an important consideration.
More energy in the form of fuel oil is consumed to dry the rock
than is consumed to ship the additional water in the wet rock,
assuming that the rock will not be dried at the final
destination. Analyses were performed to examine how energy
consumption to ship moisture in rock increases with shipping
distance and how it compares with the energy consumption to dry
the rock. In the case of rock dried at the final destination,
energy consumption would be the greatest since the energy
consumed in shipping the water would be added to the energy
consumed in drying the rock.
As stated above, the proposed Swift drying facility is subject
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to PSD Regulations. These regulations require preconstruction
monitoring of pollutant levels, application of Best Available
Control Technology (BACT), and control of emissions to insure
that PSD concentration increments are not exceeded. The rock
dryers proposed for the Swift facility will utilize venturi-
absorbers and wet centripetal vortex contact scrubbers. The
application of this technology will reduce emissions of
particulate matter and sulfur dioxide to levels well below state
and federal standards. The application of BACT wi11 also
minimize the pollutant concentration levels of airborn
rad iati on.
o Meet state of Florida and local effluent limitations for
any
di scharges.
Pursuant to Section 401 of the Federal Water Pollution Control
Act as amended (33 USC 1251, 1341), the State of Florida issues
certification to each applicant for a National Pollutant
Discharge Elimination System permit.
Al 1 recent
faci1i ti es
cond i t i ons:
NPDES permits issued by the State for phosphate mining
have been certified subject to the following
1. The applicant must comply with all applicable
of Chapter 403, Florida Statutes, and Chapter
Florida Administrative Code.
requi rements
17 series,
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 constitute
approval or disapproval of any future land alteration
activities conducted in waters of the State which require
separate Department permit(s) pursuant to Section 17-4.28,
FAC.
In accordance with Section 17-6.01(2)(a)2a.D., FAC, the
following effluent limitations apply to all discharges
designated as possibly containing contaminated runoff,
process generated wastewater, or mine dewatering
discharges from the mining and beneficiation of phosphate
rock:
Character!stic
TSS
Total P
PH
mg/1
mg/1
Di scharge
Limi tations
1-Day Max.
25
5
6. 0-9.0
30-Day Avg.
12
3
6.0-9.0
Moni tor i ng
Requi rements
l/week/24-hr. composite
1/week/24-hr. composite
I/week grab
If the above requirements are met, the discharge from this
facility will comply with Sections 301, 302, and 303 of the
Federal Water Pollution Control Act, as amended.
The Florida Department of Environmental Regulation reserves the
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right to modify the effluent limitations placed on each facility
pursuant to Federal and State law. Modifications may occur
should further water quality analysis of the proposed discharge,
its volume and character, together with the flow and
characteristics of the receiving body of water, indicate that
the discharge will not meet and comply with applicable water
quality standards contained in Chapter 17-3, Florida
Administrative Code.
Effluent limits, and any additional requirements specified in
the state certification, supersede any less stringent effluent
limits in the NPDES permit. During any time period in which
more stringent state certification effluent limits are stayed
or inoperable, the effluent limits listed in the NPDES permit
shall be in effect and fully enforceable.
0 Eliminate conventional aboveground slime-disposal areas.
The mining and reclamation plan for new-source mines should
establish a method whereby the slimes (or s 1 imes/tai 1 i"ngT
mixture) would be used for reclamation or some other purpose.
The need for an initial aboveground storage area is recognized
- as is the need for small retaining dikes around certain
areas reclaimed with a siimes/tai1 ings mixture. if the
percentage of waste clay at a mine exceeds the proportionate
amount that can be utilized, the incremental amounts beyond
that which can be handled by new siime-dewatering methods
may be placed in a holding pond for reclamation after adequate
sett 1 ing. ~~~
Swift has committed in their mine plan to use a sand-clay mix
in land reclamation and thereby reduce the need for traditional,
separate disposal areas.
A initial 480-acre conventional aboveground clay settling area
is, however, planned for the mining operation. This area will
receive all clay wastes generated before the sand-clay mix
procedure becomes operational. The settling area will remain
active throughout the mine life to receive clay wastes in excess
of the sand-clay mix requirements and to serve as a secondary
water clarification and storage area.
Based on current experimentation, sand and clay will be mixed
in the approximate ratio of 2.5 to 1 (by weight). The mixture
will be enclosed by levees averaging 1* feet in height. The
enclosed areas will be filled to 9 feet above natural grade
leaving a freeboard of 5 feet. Filling above ground is necessary
to allow for subsidence of the material as it dewaters and
consolidates, and to facilitate gravity flow within the water
return system. Approximately 5,426 acres are planned for use
as sand-clay-type disposal.
Upon completion of mining, drainage and drying will be induced
to provide for subsidence and crust development of the clay
settling area. Once the clay has subsided to the desired level,
the exterior retaining dike will be pushed towards and away from
the settling area to establish a lower grade slope and provide
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some coarser textured material for the interior soils.
o Meet Southwest Florida Water Management District
consumptive-use permit requirements.
Withdrawals of ground water from the FJoridan Aquifer will be
limited to those rates and locations included in the Consumptive
Use Permit (No. 27703739) granted by the Southwest Florida Water
Management District (SWFWMD) in September, 1978.
The permit includes details of well location and pumping rates
in the deep ground-water system and places restrictions upon
effects in both the shallow and deep ground-water systems. The
permit also requires the construction of a recharge-well system
for the purpose of recharging 3.024 million gallons per day
(average annual) from the unconfined surficial aquifer and/or
secondary artesian aquifer to the Floridan Aquifer.
Swift is obligated to the terms and conditions of the
Consumptive Use Permit. Should Swift fail to comply with all
of the conditions, set forth in the permit, then the permit shall
automatically become null and void.
o Provide storage that allows reelrculation of water recovered
from slimes.
Storage capacity is to be determined during the pending DRI
and/or the site-specific EIS based on local hydrologic
characteristics. The designed storage capacity should' allow
for capture of 100 percent of water recovered from slimes
for reuse.
The water recirculation system of the proposed mining and
beneficiation facility provides 156.03 MGD to the clay settling
area. Of this 156.03 MGD, 3.73 MGD are lost to evaporation,
11.487 MGD by clay absorption, 2.28 MGD are lost to seepage
within the recycle system, and 142.27 MGD are returned to the
process system. Ninety-nine percent of the water recoverage
from slimes by the recycle system is either returned to the plant
process or lost to non-discharge phenomena. The remaining 1%,
or 1.43 mgd, is discharged.
o Use connector wells.
Such wells offer an economical means of dewatering the shallow
ground water from the water-table aquifer before mining, while
replenishing a portion of the water pumped from the Floridan
Aquifer for the purposes of transportation and beneficiation.
Mining plans for new-source mines can continue to utilize this
method of-dewatering - but only with the following
precautionary measures; maximum utilization of water obtained
from dewatering; monitoring by both industry and regulatory
agencies to assure that the drained water meets recorrmencfed
drinking water criteria chemically, bacteriologically, and
radiologically at all times; and assurance that wells will
be adequately cemented and grouted before being abandonedT
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As a condition of the SWFWMD Consumptive Use Permit, Swift has
agreed to the installation and operation of connector wells to
recharge the Floridan Aquifer with an estimated availability
of 3 MGD. Monitoring of the quality of the water being
discharged from the shallow aquifer is required by the SWFWMD
permit for various parameters and at a specified schedule. The
water quality analysis will include the following constituents:
a) Total coliform count
b) Fecal coliform count
c) Gross alpha radiation (if
greater than 15 pCi/1
analyze for radium-226,
total radium)
d) Iron
e ) Fluor i de
f) Phosphorous
g) Sulfate
h) Pesticides
i) Organi c Carbon
j) Specific conductance
k) Nitrate
1) Phosphate (ortho, total)
m) Total dissolved solids
n) Total suspended solids
o) Turbidity
The permit further provides for the cessation of
of the water from the upper system for cause.
the introduction
Address proposed regulations regarding radiation
published by EPA and projected by mining and reel
levels to be
amation plans
for new-source mines
encountered.
based on test borings' of material to be
The DRI and/or site-specific EIS should also
develop a reclamation plan that considers radiation of spoil
material and reduces as much as possible amount of
radionuclide-bearing material left within 3-4 feet of the
surface.
The projected indoor radon progeny levels by land type for the
Duette site after reclamation are as follows: overburden
reclaimed -0.008WL (working level), sand/clay reclaimed - 0.009
WL, tailings reclaimed - 0.006 WL, clay sediments - 0.015 WL
and the weighted average for the site - 0.009 WL.
All post reclamation criteria for the radiological environment
were estimated without returned topsoil. The mining plan,
however, suggests that approximately 2 feet of topsoil may be
returned to some of the reclaimed area. This procedure is
reconmnended, since expected guidance for construction of
residential homes may require near background levels. The final
clay settling area when returned to any land use will be most
beneficially affected by returned topsoil. The 3-4 feet of
returned topsoil reconrnended in the Areawide EIS, however, may
have a high cost-benefit ratio in this region of lower matrix
radi oacti vity.
If the final guidance (EPA, 1979) for reclaimed lands suggests
an upper limit of predicted radon progeny in slab-on-grade homes
of 0.009 WL (normal background of 0.004 WL plus the uncertainty
of 0.005 WL), then the Duette site may have to consider the
return of topsoil to any residential development site.
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o Meet county and state reclamation requirements and include
j_n... the DRI and/or s i te-spec i f ic EIS an inventory of types
* ____.... . r .— _. ~..._ ^^ .__T • •Tv^iifcwt T \j x. L y LX ^
of wildlife habitat in the area to be mined and the area
immediately surrounding it.
and
o The mining and reclamation plan will take into account the
protection and restoration of habitat so selected important
species of wildlife will be adequately protected during mining
and reclamation.
Wildlife habitats with their associated fauna and flora are
described in detail in the Biology and Ecology section of this
EIS and the attendant Resource Document. Restoration or
preservation of some wildlife habitats have been incorporated
in the mining and reclamation plan. Not all areas of the
property will be mined or irrevocably disturbed. Of the unique
communities on site, fifty acres of sand pine scrub and the 18-
acre cypress dome will be preserved. Approximately 829 acres of
cut-over flatwoods excluded from mining will be restocked with
pine to enhance wildlife value.
Following the EPA recormmendat i on stated below to preserve the
section of the East Fork Manatee River scheduled for mining,
all floodplain swamps of streams having greater than 5 CFS mean
annual flow will be spared from mining and will be preserved
without modification. The major stream corridors were found
to be the most valuable wildlife habitat on-site.
o Protect or restore wetlands under the jurisdiction of the
Corps of Engineers, Section »0fr. Federal Water Pollution
Control Act, pursuant to »0» (b) Guidelines (frO CFR 230).
No specific boundaries of wetland areas have been officially
identified by the Corps of Engineers. Three categories of
wetlands were, however, established in the Central Florida
Phosphate EIS:
Category 1 - Wetlands to be protected (not mined)
Category 2 - Wetlands which may be mined but must be
restored as wetlands capable of performing
useful wetland functions
Category 3 - Wetlands which can be mined without
restoration as wetlands
Following are definitions for the categories established in the
Areawide EIS. The definitions are presented as a suggested
methodology for determining the limits of each category. These
categories should be viewed as general guidelines to rank natural
wetlands on Florida phosphate mining sites in terms of their
value to regional hydrology, water quality, and fish and
wildlife production. This categorization is intended to aide i
the EPA review process of proposed Mining/Reclamation Plans for
New Source Mines. The three categories are defined in further
detail herein for application to the review process of Swift's
Duette property.
i n
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CATEGORY 1 - Protected
Category 1 wetlands are strategically located in the regional
drainage system and are associated with or contiguous to the
primary rivers and streams (first order) and their branches
(second order) within the major drainage basins of the mining
region (e.g., Alafia, Peace, Little Manatee, Manatee, Myakka
River, Horse Creek, etc.). These streams and associated wetlands
provide an essential synergistic support to the regional
ecosystem and environment that would have an unacceptable adverse
impact if they were significantly altered, modified or
destroyed. Category 1 wetlands may include wetlands associated
with stream mains terns, headwaters and tributaries. Criteria
for determination of Category 1 wetlands include but are not
1 imi ted to:
(a) Mainstem Stream Wetlands : These are wetlands of first
and second order rivers and streams upstream to the point
where mean annual flow is 5 CFS. Protection shall extend
to the lateral wetland boundary which shall be the 25 year
flood elevation unless such calculated floodplain is less
than one-half (1/2) the total floodplain as determined by
dominant vegetation. In cases where the 25 year floodplain
is less than 1/2 the total vegetated floodplain, a minimum
of one-half (1/2) of the vegetated floodplain shall be
protected from mining and significant disturbance by mining
operat ions.
(b) Headwater Wetlands : These are wetlands as defined
by dominant vegetation that are found as the continuum
of first and second order rivers and streams upstream of
the point where mean annual flow is 5 CFS. A minimum of
twenty-five percent (25%) by area of headwater wetlands
shall be protected from mining and significant disturbance
by mining. It is the intent to maintain stream wetland
continuity by protection of headwater areas.
(c) Tributary Wetlands : Tributaries are the lateral
streams, creeks and other contiguous water conveyances
(whether permanent, intermi ttant, or seasonal) that
contribute flow to first and second order rivers and
streams. As the importance of tributary wet 1ands to
regional hydrology, water quality, and fish and wildlife
habitat may vary considerably due to contiguity,
vegetative structural diversity and hydroperiod, exact
determination as Category 1 Tributary Wet lands will
be made on a site by site basis. In all cases, however,
a minimum of twenty-five percent (25%) by area of
tributary wetlands shall be protected from mining and
significant disturbance by mining.
Although not identified above, certain wetlands not part of
stream floodplains may deserve special consideration for
inclusion in Category 1. These include unique or unusual wetland
vegetation conrmun i t i es that would be difficult if not impossible
to re-create, wetland communities rare to the site or area
wetlands supporting populations of endangered or rare animals
176
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or plants, wetlands of sufficient size to be significant wildlife
habitat (e.g., 50+ acres with considerable edge), or serve other
essential environmental functions including water quality.
CATEGORY 2 - Mine and Restore
Category 2 wetlands can be generally characterized as larger,
isolated swamps and marshes and those wetlands contiguous
to but not protected under Category 1. This Category also
includes wetlands that would otherwise be considered Category
1 but have been previously altered to an extent that
significantly impairs natural wetland function. Category
2 wetlands may be mined if an adequate restoration program
is proposed by an applicant. A restoration program must
minimally include a reasonable assemblage of indigenous
wetland plant species and be physically designed to
positively contribute to regional water quality, hydrological
function and fish and wildlife production. Criteria for
determination of Category 2 wetlands include but are not
1 imi ted to:
(a) Ma ins tern Stream Wetlands : These are all non-protected
wetlands contiguous with the first and second order
rivers and streams upstream to the point of 5 CFS mean
annual flow. This category reaches to the upland edge of
the floodplain boundary as determined by dominant vegetation
from the designated limit of Category 1 wetlands.
(b) Headwater Wetlands : These are all non-protected wetlands
that are found as the continuum of first and second order
rivers and streams upstream of the point of 5 CFS mean
annual flow. This category reaches to the upland edge of
headwater wetlands as determined by dominant vegetation
from the designated limits of Category 1 headwater
wet lands.
(c) Tributary Wetlands : These are all non-protected
wetlands is excess of 10 acres in size as determined
by dominant vegetation that are contiguous with the
lateral streams, creeks and other natural water
conveyances (whether permanent, intermi ttant, or
seasonal) that directly contribute flow to the first
and second order rivers and streams of the region.
(d) Isolated Wetlands : These are all non-protected
wetlands in excess of 5 acres in size that are not
contiguous to mainstem streams, headwaters or
tributaries but do have important functions in water
quantity and quality control and fish and wildlife
production. Isolated wetlands need not be replaced
in their original location but must be replaced in
acreage equal to total acreage destroyed within each
sub-drainage basin. Edge/area relationship should be
considered in isolated wetland replacement.
177
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CATEGORY 3 - Mine Without Restoration
Category 3 wetlands are wetlands less than 5 acres in size
as defined by dominant vegetation, are isolated, have
insignificant hydrological function and do not substantially
contribute to maintenance of fish and wildlife production
in the region.
The three categories of wetlands on the Duette site are
delineated in Figure 6-1. A segment of the East Fork Manatee
River is a major Category 1 wetland proposed for mining. EPA
recommends that this segment, as well as all other Category 1
wetlands, be preserved.
Any of the Category 2 wetlands which are proposed for mining
may be mined and must be restored. The proposed reclamation
plan will result in a net gain of 15% for swamp and marsh acreage
on the site. 6
0 Make efforts to preserve archaeological or historical sites
through avoidance or mitigate by salvage excavation performed
by a professionally 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 comnnenfT ~
One archaeological site of significance, the Carruther's Mound,
was identified on the Swift property.
The mound is in an area which is not scheduled for mining and
hence will not be destroyed in that operation. It would,
however, be isolated from its former environment. Therefore,
EPA proposes that the site be excavated under the supervision
of an individual or agency approved by the Florida Division of
Archives, History and Records Management prior to mining the
area surrounding the site.
178
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35 :14
gUl CATEGORY - 1
r?gj CATEGORY - 2
m CATEGORY - 3
FIGURE 6-1
WETLAND CATEGORIZATION
Source: Conservation Consultants, Inc.
U.S. EPA - REGION IV
DRAFT ENVIRONMENTAL
IMPACT STATEMENT FOR
SWIFT AGRICULTURAL CHEMICALS
CORPORATION PROPOSED
DUETTE MINE
MANATEE COUNTY, FLORIDA
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7.0 PROPOSED AGENCY ACTIONS
The Areawide EIS establishes a basis for initiating a site
specific EIS for a new source mining opeation. This site
specific EIS has examined the mining and reclamation plan by
Swift and assessed the impacts of the proposed activities.
The Swift proposal deviates from the Areawide EIS reconrmendations
in two significant areas: 1) construction of a rock drying
facility and 2) mining of a segment of the East Fork Manatee
River, a Category 1 wetland.
The proposed drying facility is dictated by the market conditions
under which Swift operates, and may be justified on the basis
of the amount of rock to be shipped outside of Florida for
Chemical processing. An analysis of proposed air quality impact
was performed in a manner consistent with objectives of
Prevention of Significant Deterioration (PSD) and includes
results of preconstruetion monitoring activities, control
equipment selection to achieve BACT, emissions estimates and
mathematical modeling to insure conformance with PSD increments
and National Ambient Air Quality Standards (NAAQS).
This detailed examination of short and long term areawide and
cumulative effects of the proposed drying facility has
demonstrated that air quality standards will not be violated,
air quality will not be significantly degraded, and sulfur
dioxide and particulate matter emissions will satisfy New Source
Performance Standards and Best Available Control Technology.
Therefore EPA proposes to approve the rock drying facilities
and issue the required permits pursuant to provision of the Clean
Air Act.
The segment of the East Fork Manatee River proposed for mining
has been determined to be a Category I wetland. Such wetlands
provide important ecological functions including erosion control
protection and acting as a living filter by removing sediments
and other pollutants from flood waters. In addition, these
wetlands are very productive and export a portion of this
biological productivity to downstream areas. The efficient
functioning of such a complex community is dependent upon
presence of all of its member populations. Restoration of a
major complex floodplain would be slow, if possible at all.
Thus, EPA recommends that the functioning system be left intact,
which would assure preservation of the biological integrity of
the floodplain of the East Fork of the Manatee River. Based
on the above considerations, EPA believes that mining should
not proceed in the East Fork Manatee River.
EPA proposes to issue an NPDES permit pursuant to the Clean Water
Act of 1977. The permit will include as conditions all those
recomnendations contained in the Areawide EIS which pertain to
mining except the recorrmendat i on concerning rock dryers as noted
above.
180
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Permit No. FL0036609
AUTHORIZATION TO DISCHARGE UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provisions of the Federal Water Pollution Control Act, as amended,
(33 U.S.C. 1251 et. seq; the "Act"),
Estech General Chemicals Corporation
(formerly Swift Agricultural Chemicals Corporation)
1st Commercial Bank Building
410 Cortez Road, West
Bradenton, Florida 33507
is authorized to discharge from a facility located at
Duette Mine
Between East and North Forks Manatee River
About Latitude 27° 32' 09" & Longitude 82° 07' 13"
Manatee County, Florida
to receiving waters named
East and North Forks of Manatee River
in accordance with effluent limitations, monitoring requirements and other conditions set forth
in Parts I, II, and III hereof.
This permit shall become effective on
This permit and the authorization to discharge shall expire at midnight,
Signed
Sanford W. Harvey, Jr.
Director
Enforcement Division
EPA Farm 3320-4 (10-73)
181
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00
r>o
A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
t~' • c **' '.*
During the period beginning on the effective date and lasting through the term of this"permit,
the permittee is authorized to discharge from outfall(s) serial number(s) 001, 002, and 003 process generated wastewater
mine.
Such discharges shall be limited and monitored by the permittee as specified below:
Effluent Characteristic Discharge Limitations Monitoring Requirements
kg/day (lbs/da"y) Olher Units (Specify) ~~
Measurement Sample
Daily Avg Daily Max Daily Avg Daily Max Frequency Type
(During Discharge)
F!ow-m3/Day (MGD) --..__ I/Week Discrete*
Total Suspended Solids — — 30 mg/1 60 mg/1 I/Week 24 Hr. Composite
Total Fluoride (33 F) — — 10 mg/l 10 mg/1 I/Week 24 Hr. Composite
*Any measurement or determination representative of the actual discharge.
*Any measurement or determination representative of the actual flow.
Any overflow from facilities designed, 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 effluent and pi! limitations listed on this page.
The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be
monitored I/week during discharge 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 location(s): nearest accessible point after final treatment but prior to actual discharge
or mixing with the receiving stream.
The effluent limits, and any additional requirements, specified in the attached 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 effprr .nml full™ or,f^»-^^-,ui^
ii * >
2 * 3
•*i g,
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DEFINITIONS
(a.)
T" I"7 Water that ±9 ^P™"** or that collects in the
water
CO
CO
(b.).
preclPitation event" shall mean the maximum 24-hour precipitation
available in "u "-occurrence internal of once in 10 year. This information is
Environment I n f f T*" Technlcal PaPer No« ^0. ^y 1961 and may be obtained from the
S ComeJce? Service- Natio" Oceanic and Atmospheric Administration. U.S. Department
The term "mine" shall mean an area of land, surface or underground, actively used for or
resulting from the extraction of a mineral from natural deposits.
wastewater" »»»11 mean any wastewater used in the slurry
The term .n ' ^ emlssions <=ontrol, or processing exclusive of mining.
in a oit nnnH i*° <* *"* ^^ ™ter Which bec°mes commingled with such wastewater
was?cwate "' °* ^^ £acili^ used ^r settling or treatment of such
n d
i »
a n
2! O
O «•
I-1
O
O
UJ
0>
o>
O
I
H
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PARTI
Page 4 of 10
Permit No. FL0036609
B. SCHEDULE OF COMPLIANCE
1. The permittee shall achieve compliance with the effluent limitations specified for
discharges in accordance with the following schedule:
a. Permittee shall comply with the effluent limitations by
the effective date of the permit.
b.
This permit shall be modified, or alternatively, revoked
and reissued, to comply with any applicable effluent
standard or limitation issued or approved under sections
301(b)(2) (c), (D), (E), and(F), 304(b)(2), and 307 (a) (2) of the
Clean Water Act, if the effluent standard or limitation
so issued or approved:
(1) Contains different conditions or is
otherwise more stringent than any
effluent limitation in the permit; or
(2) Controls any pollutant not limited in the permit.
The permit as modified or reissued under this paragraph
shall also contain any other requirements of the Act
then applicable.
2. No later than 14 calendar days 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 actions 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.
184
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PART I
Rape 5 of 10
Permit No. FL0036609
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 the previous 3 months shall be summarized for
each month and reported on a Discharge Monitoring Report Form (EPA No. 3320-1),
postmarked no later than the 28th day of the month following the completed reporting
period. The first report is due on December 31, 1979 . Duplicate signed copies of
these, and all other reports required herein, shall be submitted to the Regional
Administrator and the State at the following addresses:
Environmental Protection Agency
Water Enforcement Branch
345 Courtland Street, N.E.
Atlanta, Georgia 30308
3. Definitions
a. The "daily average" discharge means the total discharge by weight during a calendar
month divided by the number of days in the month that the production or
commercial facility was ope ting. Where less than daily sampling is required by this
permit, the daily average discharge shall be determined by the summation of all the
measured daily discharges by weight divided by the number of days during the
calendar month when the measurements were made.
b. The "daily maximum" discharge means the total discharge by weight during any
calendar day.
4. Test Procedures
Test procedures for the analysis of pollutants shall conform to regulations published
pursuant to Section 304(g) of the Act, under which such procedures may be required.
5. 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 dates the analyses were performed;
c. The person(s) who performed the analyses;
185
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PARTH
Page 7 of 10
Permit No. FL0036609
A. MANAGEMENT REQUIREMENTS
1. Change in Discharge
All discharges authorized herein shall be consistent with the terms and conditions of this
permit. The discharge of any pollutant identified in this permit more frequently than or
at a level in excess of that authorized shall constitute a violation of the permit 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 or, if such changes will not violate the effluent
limitations specified in this permit, by notice to the permit issuing authority of such
changes. Following such notice, the permit may be modified to specify and limit any
pollutants not previously limited.
2. Noncompliance Notification
If, for any reason, the permittee does not comply with or will be unable to comply with
any daily maximum effluent limitation specified in this permit, the permittee shall
provide the Regional Administrator and the State with the following information in
writing, within five (5) days of becoming aware of such condition:
a. A description of the discharge and cause of noncompliance; and
b. The period of noncompliance, including exact dates and times; or, if not corrected
the anticipated time the noncompliance is expected to continue, and steps being
taken to reduce, eliminate and prevent recurrence of the noncomplying discharge.
3. Facilities Operation
The permittee shall at all times maintain in good working order and operate as efficiently
as possible all treatment or control facilities or systems installed or used by the permittee
to achieve compliance with the terms and conditions of this permit.
4. Adverse Impact
The permittee shall take all reasonable steps to minimize any adverse impact to navigable
waters resulting from noncompliance with any effluent limitations specified in this
permit, including such accelerated or additional monitoring as necessary to determine the
nature and impact of the noncomplying discharge.
5. Bypassing
Any diversion from or bypass of facilities necessary to maintain compliance with the
terms and conditions of this permit is prohibited, except (i) where unavoidable to prevent
W™,M J °r ^^ P1iOPerty damage> °r (H) Where excessiv* storm drainage or runoff
Zhih-?*™86 rT S necessary for compliance with the effluent limitations and
prohibitions of this permit. The permittee shall promptly notify the Regional
Administrator and the State in writing of each such diversion or bypass
186
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^ B% $1 Rp^lF
ife
PART I.
Page 9 of 10
Permit No. FL0036609
inspection at the offices of the State water pollution control agency and the Regional
Administrator. 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.
4. Permit Modification
After notice and opportunity for a hearing, this permit may be modified, suspended, or
revoked in whole or in part during its term for cause 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; or
c. A change in any condition that requires either a temporary or permanent reduction or
elimination of the authorized discharge.
5. Toxic Pollutants
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 and such standard or prohibition is more stringent than any limitation for such
pollutant in this permit, this permit shall be revised or modified in accordance with the
toxic effluent standard or prohr tion and the permittee so notified.
6. Civil and Criminal Liability
Except as provided in permit conditions on "Bypassing" (Part II, A-5) and "Power
Failures" (Part II, A-7), nothing in this permit shall be construed to relieve the permittee
from civil or criminal pena'ties for noncompliance.
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.
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.
187
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PART II
10 of 10
FWmitNo. FL0036609
9. 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,
ihall not be affected thereby.
PART III
Definitions
1. The "daily average" concentration means the arithmetic average
(weighted by flow value) of all the daily determinations of con-
centration made during a calendar month. Daily determinations of
concentration made using a composite sample shall be the concentra-
tion of the composite sample. When grab samples are used, the
daily determination of concentration shall be the arithmetic
average (weighted by flow value) of all the sample collected during
that calendar day.
2. The "daily maximum" concentration means the daily determination of
concentration for any calendar day.
3. "Weighted by flow value" means the summation of each sample concen-
tration times its respective flow in convenient units divided by
the summation of the respective flows.
4. Composite Sample: A "24-hr, composite sample" is any of the following:
a. Not less than six influent or effluent portions collected at
regular intervals over a period of 24 hours and composited in
proportion to flow.
b. Not less than six equal volume influent or effluent portions
collected over a period of 24 hours and composited in proportion
to the flow. " *
C. An influent or effluent portion collected continuously over
a period of 24 hours at a rate proportional to the flow.
5. For the purpose of this permit, a calendar day is defined as any
consecutive 24-hour period.
188
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COORDINATION LIST
The following Federal, State,
groups have been requested to
and local agencies and interested
comment on this impact statement:
Federal Agencies
Bureau of Outdoor Recreation
Bu reau of Mi nes
Coast Guard
Corps of Engineers
Council on Environmental Quality
Department of Agriculture
Department of Commerce
Department of Health, Education
and Welfare
Department of the Interior
Department of Transportation
Energy Research and
Development Agency
Federal Highway Administration
Fish & Wildlife Service
Food and Drug Administration
Forest Service
Geological Survey
National Park Service
Nuclear Regulatory Commission
Soil Conservation Service
Economic Development
Admini strati on
Members of Congress
Honorable Lawton Chiles
United States Senate
Honorable Sam Gibbons
U. S. House of Representatives
Honorable Skip Bafalis
U. S. House of Representatives
Honorable D. Robert Graham
Governor
Patrick K. NeaI
State Senator
Ralph H. Haben, Jr.
State Representative
Lawrence F. Shackleford
State Representative
Thomas E. Danson, 3r.
State Representative
Ted Ewing
State Representative
Coastal Coordinating Council
Department of Natural Resources
Department of Agriculture and
Consumer Services
Honorable Richard Stone
United States Senate
Honorable Andy P. Ireland
U. S House of Representatives
State
Department of Administration
Department of State
Environmental Regulation
Cormni ttee
Geological Survey
Game and Freshwater Fish
Cormni ss i on
Department of Commerce
Department of Health and
Rehabilitative Services
Bureau of Intergovernmental
Re 1 at i ons
Department of Environmental
Regulat ion
Interest Groups
The Fertilizer Institute
Florida Phosphate Council
Florida Audubon Society
Flor i da Si erra Club
Tampa Audubon Society
Florida Defenders of the
Envi ronment
Izaac Walton League of America
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Manasota 88
League of Women
Conser vat i on
Count y
Voters
Counc i1 of
Flor i da Di vi s i on
Florida Wildlife Federation
Manatee
Local and Regional
Polk County Conrmission
Hillsborough County Conmission
Manatee County Commission
DeSoto County Conrmission
Hardee County Comnission
Charlotte County Commission
Sarasota County Conrmission
Tampa Bay Regional Planning Council
Sarasota County Health Dept.
Hillsborough County Department
of Environmental Protection
Manatee County Department of
Pollution Control
Sarasota County Environmental
Control Department
Southwest Florida Water
Management District
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LIST OF PREPARERS
United States Environmental Protection Agency
Andrea E. Zirmner
Ro b e r t B. Howa r d
John E. Hagan, TI I
Charles P
Thomas R.
Alfred E.
Delbert B
William L
James E. Or ban
Roger Pfaff
Joel G. Veater
Al bus
Cav i nder
Coker
Hicks
Kr uczynski
Project Manager
Chief, EIS Preparation
Chief, EIS Branch
NPDES Permit
Surface Water
Ground Water
Biology and Ecology
Biology and Ecology
No i se
Air
Radiation
Sect i on
Conservation Consultants, Inc.
Wi 1 1 i am W. Hami 1 ton
H. Clayton Robertson
Andre F. Clewell, Ph. D.
Richard M. Eckenrod, P. E.
Byron E. Nelson
John F. Schatmeyer, Ph. D., P. E.
Senior Project Manager
Assistant Project Manager
Biology and Ecology
Surface Water Quality
Noi se
Ai r Quali ty
Civil Engineering Consultants, Inc.
Robert 3. Lombardo, P. E., I. T. E. Transportation
Leggette, Brashears, & Graham, Inc.
Frank H. Crurn
Harry F. Oleson, Jr.
Ground Water
Ground Water
David E. Wilkinson
Planning/Marketing Services, Inc.
Soc i oeconomi cs
Zellars-Wi 11iams, Inc.
Mi chae1 E. Ze11ar s
Douglas E. Blows
Luther H. Bumgardner
W. H. Hawkins
Ronald R. Potts
James M. Williams
Project Manager, Geology
Water Balance, Mining
Engi neer i ng
Geology, Mining Engineering
Soi 1 s
Water Discharge
Process Engineering
m
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Cons ultant s
Melvin W. Anderson, Ph. D., P. E. Surface Water Hydrology
Ertinett Bolch, Ph. D. , P. E. Radiation
Roger T. Grange Archaeological & Historical
Properties
.1. Raymond Wil I iams Archaeological & Historical
Proper t i es
iv
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SELECTED BIBLIOGRAPHY
American Water Works Association, Inc. 1971. Water quality and treatment:
A Handbook of Public Water Supplies. McGraw-Hill Book Company. New
York.
Ardaman & Associates, Inc. 1975. General Soil Characteristics and
Descriptions for Manatee County, Florida.
Ardaman & Associates, Inc. 1975. Proposed Phosphate Mining, Swift Chemical
Company, Manatee County, Florida. Part I. (Mimeo. Rept.)
Ardaman & Associates, Inc. 1977. Flood Plain Studies, Swift DRI, Manatee
County, Florida. File Number 74-0271.
Ardaman & Associates, Inc. 1978. 1977 Hydrological Monitoring Program,
Swift Agricultural Chemicals Corporation, Manatee County, Florida.
Prepared for Swift Agricultural Chemicals Corporation, Bartow,
Florida.
Ardaman & Associates, Inc. 1979. Impact Evaluation, Hypothetical Failure
of Initial Settling Area, Duette Mine, Manatee County, Florida.
Prepared for Swift Agricultural Chemicals Corporation, Bradenton,
Florida.
Ardaman & Associates, Inc. 1979a. Letter report to Conservation Consultants,
Inc., July 20, 1979.
Ardaman & Associates, Inc. 1979b. Letter report to Conservation Consultants,
Inc., July 31 , 1979.
Barnett, B. S. 1972. The Freshwater Fishes of the Hillsborough River
Drainage, Florida. M.S. Thesis, University of South Florida. Tampa
84 pp.
Barton, B. A. 1977. Short-term effects of highway construction on the
limnology of a small stream in southern Ontario. Freshwater Biol.
7: 99-108.
Beck, H. L., and dePlanque, G. The Radiation Field in Air Due to Distri-
buted Gamma-Ray Sources in the Ground. Rep. HASL-195. USAEC,
Washington, D.C. 1968.
Beck, William M., Jr. 1954. Studies in stream pollution biology. I. A
simplified ecological classification of organisms. Quart. Journ. Fla.
Acad. Sci. 17(4): 211-227.
Beck, William M., Jr. 1955. Suggested method for reporting biotic data.
Sewage and Industrial Wastes, 27(10): 1193-1197.
-------
Bennett, G. W. 1970. Management of Lakes and Ponds (Second Edition).
'van Nostrand Reinhold Co. New York. 375 pp.
Beranek, Leo L. 1971. Noise and Vibration Control, McGraw-Hill Book Company
New York.
Berra T M., and G. E. Gunning. 1970. Repopulation of experimentally
decimated sections of streams by longear sunfish, Lepomis megalotis
megalotis (Rafinesque). Trans. Amer. Fish. Soc. 99(4): 776-781.
Bradley, James T. 1972. Climates of the United States, Climate of Florida,
Climatography of the United States No. 60-8. N.O.A.A. Environmental
Data Service.
Brezonik, P. L., W. H. Morgan, E. E. Shannon, and H. D. Putnam. 1969.
Eutrophication factors in north central Florida akes. Eng. Prog.
Univ. Fla. 23(8): 1-101.
Bromwell Engineering. 1977. Characterization of Waste Clay Samples for
Swift Agricultural Chemicals Corporation.
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