EPA 660/2-74-067
June 1974
Environmental Protection Technology Series
Pollutional Problems and
Research Needs For
An Oil Shale Industry
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to fche ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology to repair or prevent environmental
degradation from point and .non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards*
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EPA-660/2-7l*-067
June 1971*
POLLUTIONAL PROBLEMS AND RESEARCH
NEEDS FOR AN OIL SHALE INDUSTRY
By
Fred M. Pfeffer
Mining Wastes Section
Treatment and Control Technology Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 7^820
Project No. 1U030 ETY
Program Element IBBOliO
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
For sale by the Superintendent ol Documents, U.S. Government Printing Office, Wuhincton. D.C. 20KB • Price 85 cents
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ABSTRACT
The oil shade resources and surface stream drainage within the Green
River Formation of Colorado, Utah, and Wyoming are presented briefly.
The aboveground retorting processes of the Bureau of Mines, Union
Oil Company, and The Oil Shale Corporation are described, as are the
physical and leaching characteristics of spent shale residues derived
from each process. Oil shale retorting in place (in situ) is summarized.
The area of major concern, stabilization of spent shale residues, is
covered in detail. Other areas of environmental concern are dis-
cussed: retort wastewater, process water from shale-oil upgrading,
dewatering operations, mineral recovery, and contamination of
groundwater by radioactivity. Research needs are presented: a
tri-state groundwater report; environmental base line data; an assess-
ment of total environmental impact; pollution control guidelines; effluent
limitations; and continuous EPA monitoring.
ii
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CONTENTS
Section Page
I CONCLUSIONS 1
II RECOMMENDATIONS 2
III INTRODUCTION 3
IV AREA OF MAJOR ENVIRONMENTAL CONCERN 9
V OTHER AREAS OF ENVIRONMENTAL CONCERN 14
VI RESEARCH NEEDS 21
VII REFERENCES 24
VIII APPENDIXES 27
iii
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FIGURES
No. Page
1 BOUNDARIES AND SURFACE DRAINAGE OF THE
GREEN RIVER FORMATION 6
2 SHALE OIL UPGRADING PROCESS 17
3 BUREAU OF MINES GAS-COMBUSTION RETORTING
PROCESS 30
4 UNION OIL RETORTING PROCESS 31
5 TOSCO RETORTING PROCESS 33
IV
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No,
TABLES
1 SURFACE WATER DATA IN THE VICINITY OF THE
GREEN RIVER FORMATION 5
2 COMPARATIVE CHARACTERISTICS OF PETROLEUM
AND SHALE OIL 7
3 ANALYSIS OF RETORT WASTEWATER FROM THE
BUREAU OF MINES PROCESS 15
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SECTION I
CONCLUSIONS
1. The stabilization of spent shale residues is the major environmental
problem confronting the developing oil shale industry and EPA. Recla-
mation of the disposal site is second in priority to effective stabilization.
2. Freeze-thaw conditions and water saturation can result in the mass
movement of spent shale through slumping and sliding. Adequate
measures can be taken to prevent this occurrence.
3. Because of the water requirements for spent shale disposal, proc-
ess waters need not be a pollutional problem. Furthermore, a closed
system for water seepage at the disposal site will prevent pollution by
salt transport.
4. Solutions to other environmental problems associated with commer-
cial oil shale processing are actively being sought or will be realized
before the industry develops to full-scale. Therefore, these are areas
of lesser concern in comparison to spent shale stabilization.
5. Research needs remaining in the field of oil shale development that
require a continued EPA effort include: delineating groundwater resources
for the tri-state oil shale region; establishing pollution control guidelines
and effluent limitations for the industry; monitoring oil shale development;
obtaining environmental base line data; and preparing an assessment of
total environmental impact.
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SECTION II
RECOMMENDATIONS
1. In disposing of spent shale, the industry needs to concentrate efforts
on mass stabilization.
2. There are gaps in available groundwater information for the area
of proposed oil shale development. In addition, the impact of the
industry on this water resource is uncertain. For these reasons,
EPA should conduct or support a study of groundwater qualities,
pumping yields, locations, and movements, especially emphasizing
the proposed lease sites.
3, As the unit operations of the industry are revealed, EPA should
conduct surveys of water quality for the streams affected, and determine
waste loadings and treatment efficiencies. Establishment of effluent limita-
tions and pollution control guidelines should be based upon this information,
4. Procedures should be implemented to control high-grading of the
shale, to avoid oil extraction at the expense of aluminum and bicarbonate
compounds, and to insure optimized techniques in backfilling with spent
shale residues.
5. Continued EPA involvement in environmental aspects of oil shale
research and in monitoring the developing industry is recommended,
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SECTION III
INTRODUCTION
The United States faces an unprecedented energy crisis and a long-term
need for, developing major new domestic sources of energy. One such
untapped source is oil shale. Oil derived from shale is currently receiving
attention for several reasons. The average price of domestic petroleum is
about $7.00 per barrel. The estimated price range of shale oil is $4.00 to
$6.00 per barrel, dependent on many variables including the degree of
upgrading or prereflning. Prerefining of the retort product (shale oil)
yields a premium feedstock of constant quality, containing virtually no
sulfur. Strategically, oil shale is a domestic resource capable of providing
oil from a single, small geographic area for an unusually long duration
(perhaps 200 years) . Although major deposits are scattered from Texas
to the Great Lakes, the areas having at least 25 feet of continuous beds
yielding >25 gallons of oil per ton are confined to the Green River Forma-
tion underlying 16,500 square miles in Colorado, Utah, and Wyoming
(Figure 1) . These beds are estimated to contain 660 billion barrels of
oil, a figure comparable to the world's proven reserves of crude petro-
leum. Roughly 75 percent is contained in the 1,600 square mile Piceance
Creek Basin, marking this area as the probable site of the first commercial
oil shale operation.1 Of the proven reserves, roughly 80 billion barrels
are considered to be recoverable using current technology. For compara-
tive purposes, approximately 100 billion barrels of petroleum have been
produced by the United States since the Civil War.
Surface water in the area of the Green River Formation drains to the
Colorado River. Pertinent quality and flow data compiled by USGS are
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presented in Table 1. Sampling locations correspond to the numbered
designations in Figure 1.
At present, the most economical method for extracting the organic material
from shale involves the destructive pyrolysis of crushed ore at atmospheric
pressure at approximately 900° F. Following this retorting process, the
organics are released as an oil vapor. The hydrocarbon condensation
products of the vapor constitute shale oil; its characteristics depend on
the shale source and the retorting procedure utilized. Compared to petro-
leum, the product is a heavy, viscous oil having a high pour-point and
elevated nitrogen and sulfur content (Table 2) .
Two methods of processing oil shale are receiving consideration at this
time. The first has been tested extensively on a pilot scale and will
probably constitute the initial stage of the industry. It consists of mining
oil shale, crushing and retorting the material in surface operations, and
disposing of spent shale residue. Following utilization of wastewater in
quenching, the net products are shale oil, mine overburden, and spent
shale ash. The second method of extracting oil involves retorting oil
shale in place (in situ). The technical aspects of this method are in the
experimental stages of development. The subsurface shale formation is
first penetrated by drilling. In one approach, conventional or nuclear
explosives are placed beneath or within the formation and detonated. It
is believed that a subsurface rubble pile surrounded by fractured shale
will be the result of a contained nuclear explosion. Another approach
consists of combining conventional explosives with hydraulic fracturing
to increase permeability of the formation. In either event, a network of
wells is then installed. The fractured shale is retorted with an induced
fire front, and a water-shale oil mixture is pumped to the surface for
separation. The net products of an m situ operation are shale oil and a
wastewater that requires treatment. Above-ground retorting will likely
be utilized initially for full-scale operations since the process is more
advanced than the in sjtu method at the pilot scale.
Industry and the Federal Government are directing efforts toward develop-
ing oil shale resources on private and public domain in the Green River
4
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Table 1. SURFACE WATER DATA IN THE VICINITY OF THE GREEN RIVER FORMATION
Weighted average 10/61 -
Stream
Sample
Point
1.
2.
3.
4.
5.
Sampling
Point
Description
Colo . R . near
Glen wood
Springs, Colo.
Colo. R. near
Cameo, Colo.
Colo . R . near
Cisco, Utah
White R. near
Watson, Utah
Yampa R. near
Maybell, Colo.
pH
7.5
7.6
7.7
7.9
7.3
TDS
(mg/1)
240
328
488
447
180
Ca Na
(mg/1) (mg/1)
27
52 49
74 64
62
18
HCO,
(mg/1)
114
139
150
206
108
09/622
SO
(mg/1)
60
74
182
149
47
Mean
Flow
(cfs)
3,305
5,525
9,250
920
2,060
Wt. avg.
1951-1960
Mean
Flow
(cfs)
— —
—
6,475
680
1,450
6.
7.
Green R. near
Green River,
Wyo.
Green R. at
Green River,
Utah
7.8 267
7.9 395
26 168 80 2,005 1,615
49
178 143 8,050 5,550
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»... -''Great DtvideBa8wt->
Scale in Miles
/— Green River
Formation
\ RIFLE Q_-^"
tfrond ;
MWO..'
%^
-- Stream Sampling
Points
FIGURE I - BOUNDARIES AND SURFACE DRAINAGE OF THE
GREEN RIVER FORMATION
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Table 2. COMPARATIVE CHARACTERISTICS OF PETROLEUM AND SHALE OIL4' 5
Gravity Sulfur
Source °API Wt %
Midcontinent
Petroleum 39.0 0.14
Shale oil from
Colorado shale 16.0- 0.6-
by five retort 25.7 0.8
Pour
Nitrogen Point
Wt% °F
0 5
1.6- 60-
2.2 90
Analysis of Distillates Boiling
Below 600° F (Vol. %)
Saturates
90
26-
36
Olefins
0
36-
46
Aromancs
10
28-
32
methods
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Formation. The Colony Development Operation has begun construction of
a 50,000 bbl/day plant. Government interest results from the occurrence
of approximately 75 percent of the high-grade oil shale deposits on public
land, the majority under the jurisdiction of the U.S. Department of Interior.
The Interior is completing a program for leasing oil shale property to
industry for testing of the economics of production and safeguarding the
environment.
Future exploitation of public oil shale reserves will be based on initial
program results. Six leases (5,120 acres each) have been offered for
sale on a competitive basis in 1974. The sites were selected to test the
possible mining methods, surface, underground, and in situ. The extrac-
tion procedure will depend upon the depth of overburden and the thickness
and structural integrity of the oil shale beds. For example, in the center
of the Piceance Creek Basin of Colorado, high grade shale occurs in beds
up to 2,000 feet thick, but overburden may be as great as 1,000 feet.
Current open-pit technology in coal mining is limited to approximately
400 feet of overburden. The room-and-pillar method, or another under-
ground procedure, would be indicated in this instance. The method
employed will depend upon the bed thickness and the degree of fracturing.
Pursuant to Section 102(2) (C) of the National Environmental Policy Act of
1969 (see Appendix A) , the Department of Interior initiated a study of the
leasing program in 1970 with special emphasis on environmental considera-
tions. At the Department's request, the States of Colorado, Utah, and
Wyoming each formed committees represented by Federal, State, and local
government and industry, The committees prepared formal reports
describing reserves, lease sites, shale processing systems, and environ-
678
mental factors within each State. ' ' The Department of Interior has
drafted a statement on environmental impact that draws upon information
gathered from the State reports, other Federal agencies, interested State
and local agencies, citizens at large, and standing Federal regulations.
The present report defines the areas of environmental concern and research
needs based on the Federal and State reports, in-house and extramural
research, a review of the literature, and personal contacts.
8
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SECTION IV
AREA OF MAJOR ENVIRONMENTAL CONCERN
Aboveground retorting operations will result in the surface disposal of
significant quantities of retorted oil shale residues for two reasons.
First, when raw shale is crushed prior to retorting, the volume per
unit mass is doubled. Approximately 40% of the volume is lost in retort-
ing .10 It follows that spent shale occupies a volume roughly 20%
greater than raw shale in place. Second, spent shale disposal at mine
sites cannot occur until adequate void space is available. The magni-
tude of solid waste disposal is difficult to predict at this time, for it
will depend upon the grade and crushing requirements of raw shale,
the retorting method and temperature to which the shale is subjected,
the amount returned in mining operations, by-product usage in the
immediate area (highway base material or construction aggregate) , and
whether or not saline minerals are recovered. Surface mine spoils and
crushing fines unsuitable for retorting magnify the solid waste disposal
problem. However, using the 20% figure above, a 50,000 bbl/day plant
could produce as much as 260,000 ft /day spent shale in excess of that
returned to the mine (note; assuming raw shale assays 25 gal./ton and
occupies 15.5 ft3/ton in place) . This production would be sufficient to
cover Washington, D.C. (area 65 square miles) to a depth of 1/2 inch
per year. The proposed one million bbl/day minimum for economic
operation in Colorado would increase the figure to almost one foot per
year.
The probability that long reaches of canyons will be filled with waste
shale to depths of perhaps 600 feet indicated a need for testing the
stability of the material to rainfall and snowfall on a pilot scale. This
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would allow a meaningful prediction of the ultimate environmental
impact. Accordingly, Colorado State University was awarded an EPA
grant to perform a rainfall study using retorted shale residues from the
three most promising aboveground retorting methods most thoroughly
tested at the time. These were the Bureau of Mines gas-combustion
process, the Union Oil Company counter current process, and The Oil
Shale Corporation (TOSCO) process (Appendix B—process descrip-
tions; Appendix C—spent shale characteristics) . The three processes
were examined to determine variations in the spent shale residues
resulting from crushing and retorting operations. Maximum raw shale
size for the Bureau of Mines and Union processes is 3.5 inches, while
that for the TOSCO method is 0.5 inch. Virtually all of the carbon
residue is burned off retorted shale in the Union and Bureau of Mines
retorts. The residual solid wastes are large, fused clinkers from the
Union process, particles up to 3 inches from the Bureau of Mines retort,
and a finely-divided, black residue from the TOSCO process. Of the
three processes, the TOSCO processed shale was afforded the most
consideration as this process was the closest to commercial development.
A description of TOSCO shale and its emplacement and compaction on the
facility is given in Appendix D. Thirteen applications of rainfall were
made, amounting to three years of precipitation in the area proposed for
oil shale development. Rainfall events were spread over a three month
period to allow for surface drying between applications. At the con-
clusion of the rainfall investigation, snowfall (artificial and natural)
studies were conducted for the U.S. Bureau of Mines. A total of 4.75
inches of water as snow was applied to the facility during four snowfall
events,
Water penetration was negligible in the rainfall studies. The change
in moisture content one foot below the surface at the downstream end
was only about 10% from beginning to end of the study. The wet shale
surface several hours after rainfall remained sufficiently firm to
support walking and register little or no footprints. The surface
10
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runoff contained 200-700 mg/1 total dissolved solids. Black settleable
fines were transported in the runoff at rates up to 0.1 pound per square
foot of surface area per hour of application.
Results of the snowfall study revealed that the concentration range of
dissolved solids in the runoff (50-450 mg/1) was lower than in the
rainfall-runoff. Because of the low rate of runoff from melting snow,
suspended fines were negligible. The important findings related to
percolation. Long periods of contact as the snow melted permitted
water penetration into the bed of residue and subsequent saturation to
the maximum depth of the experimental plot (2 feet) . Saturation reduced
the effects of compaction, and the surface no longer supported walking.
It is important to note that the results are for one sample produced by
only one retort method under a single set of retorting conditions. The
exact nature of retorted shale at the time of deposition in the environment
and its fate and effects in that environment are unpredictable. However,
the experiments reveal that in order to stabilize a disposal site contain-
ing shale of the general nature tested, moisture content of the contained
shale must be controlled.
Conditions approaching water saturation could ultimately result in mass
movement brought about by reoccurring slope failures (slumping,
sliding, or seismically-induced liquifaction) . The following methods
are suggested to prevent this situation:
(a) Preliminary assessment of a suitable disposal site must be made on
the basis of the relative danger from erosion. Criteria include evidence
of past erosion, water flows, tendency for flash flooding, elevation
changes, and remoteness.
(b) The base footing of the pile could become a critical factor if the
seasonal variation in groundwater tables results in free water on or near
the surface. Spring discharge from alluvial aquifers may represent the
total flow of normally-dry stream beds. Compression of the soil material
in the canyon floor could result in the rise of free water to the base of
11
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the pile and saturation of the lower layers of the pile. To prevent this
occurrence, the effective water table should .be lowered by means of
drainage channels in the canyon floor.
(c) If spent shale is deposited as a water slurry, retaining dikes should
be designed to facilitate shale dewatering and prevent a state of prolonged
saturation. An approach similar to the design of dams for mill tailings is
14
suggested. Due to high salinity and the water requirements for hydraulic
transport, it is expected that runoff and leach-water seepage will be inter-
cepted by catch basins at the toe of the embankment and diverted through
sealed trenches and ponds for recycle.
(d) Upstream surface water and side wall canyon runoff should be diverted
around the dump site to prevent shale saturation. As an added benefit,
this will lower the water table in shallow aquifers beneath the pile.
(e) Erosion during heavy rainfall could be minimized by contouring the
surfaces in benches.
(f) The contained shale should be equipped with instrumentation to
monitor the moisture content and the free water tables and water move-
ment. Following final compaction of the shale surface, exposed surfaces
should be permanently sealed to water penetration. Sealing could
be accomplished economically and effectively by working into the sur-
face a material such as bentonite-clay. The resulting impermeable
barrier should be covered with a layer of sand or crushed rock followed
by native overburden or conditioned soil. The total depth of fill over
the barrier should exceed the freezing line depth of the region by a
margin of safety. Soil surfaces may then be revegetated, taking
advantage of past successes by the industry and using native plant
cover with reasonably shallow root structures.
Much emphasis has been placed on revegetating spent shale dumps to
achieve stability, support native grazing animals, or restore the aesthetic
(\ 7 R Q
beauty of the countryside. ' ' ' These references suggest that the
shale pile can be compacted, covered with an enriched soil, and
12
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revegetated; thereby the site is stabilized and the aesthetics preserved.
However, drought, fires in dry seasons, or overgrazing could result
in the loss of the vegetative cover followed by soil erosion, exposure
of the shale surfaces, water penetration, and saturation. The approach
previously presented is believed to offer a greater safeguard to the
environment: (1) prevention of shale saturation with effective barriers,
(2) drainage of water away from the top surface barrier by means of a
sand or rock layer, (3) retention of the sand layer with overburden,
and (4) stabilization of the overburden with a vegetative cover unmolested
by foraging animals. This may be accomplished by fencing off areas
planted in staple browse, such as sagebrush and juniper, or by covering
with "unattractive" plants which have grown by natural succession on
abandoned mine sites in the area.
13
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SECTION V
OTHER AREAS OF ENVIRONMENTAL CONCERN
RETORT WATER
Retort water is the waste effluent separated from shale oil following oil
shale pyrolysis either in the formation underground (in situ) or
aboveground. The volume and characteristics of the waste are depend-
ent upon the process and the operational parameters of retorting. With
process control, little or no water may be produced. The upper limit
anticipated is 1.4 weight percent of raw shale, or 3 gal. /ton. The
wastewater poses a serious problem if released to surface or subsur-
face fresh water. It contains significant concentrations of dissolved
organics and inorganics, emulsified oil, and finely divided suspended
matter. Table 3 is an example but should not be construed as repre-
sentative of the waste on a commercial scale.
Wastewater generated from aboveground retorting operations will likely
be consumed as makeup water for dust control (at shale conveyors and
crushers) and for spent shale disposal (quenching, hydraulic trans-
port, and compaction). The Colony Development Operation has proposed
recovery of ammonia and sulfur from foul wastewaters generated by the
TOSCO retorting process. Salt leaching of spent shale will result from
the usage of retort water in disposal operations (Appendix C contains
leachate characteristics). However, proper waste pile construction
(Section IV) would prevent salt from leaching into a fresh water resource.
Volumes of water in excess of retort water will be required for quenching,
moistening, and dust control.
14
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Table 3. ANALYSIS OF RETORT WASTEWATER
FROM THE BUREAU OF MINES PROCESS*
Total Solids (103° C), mg/1 3,000
Nonvolatile Total Solids (600° C) 1.700
P** 8.5-9,5
Ammonia (Direct Nesslerization), mg/1 NH. ... 2,500
Chemical Oxygen Demand, mg/1 Ox. Dem. . . . 6,700
Total Carbon, mg/1 C 2,150
Nonvolatile Organic Carbon, mg/1 C 1,600
Predominant Inorganic Species: Na+1, Ca*2, NH*1, Cl"1,
SO'2, HCO"1, CO'2.
Predominant Organic Species: Complex mixture of dissolved
and suspended organics.
*Analysis by the Bureau of Mines, Laramie, Wyoming.
Wastewater generated from in situ retorting will require special han-
dling. The U.S. Bureau of Mines, Laramie, Wyoming, in conjunction
with its in situ experiments. is studying constituents of the wastewater,
treatability, and possibilities for by-product recovery.1 Based on
the results of bench studies, the group has proposed a treatment scheme
as follows: (1) lime and heat addition to remove carbonates, ammonia,
and some organics; (2) carbon adsorption to remove the balance of
organics; and (3) ion exchange to remove the remaining ionic species.18
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Regeneration of the ion exchange media will yield a solution of ions more
concentrated than that of the carbon adsorption effluent. The end results
of treatment are purified retort waste-water and a relatively smaller vol-
ume of brine from the regeneration process that will require additional
treatment or control.
PROCESS WATER FROM SHALE-OIL UPGRADING
It is anticipated that shale-oil refining to finished products will not
take place in the region of oil shale development because of the limited
availability of water for refinery cooling operations. However, several
unique characteristics of crude shale oil suggest the advisability of
pre-refining steps before pipelining to major petroleum refining centers,
water availability permitting. Compared to good petroleum crude, shale
oil has a high pour-point and viscosity (making pipelining difficult at
cold temperatures) , is unstable (due to a high olefinic content), and
possesses greater concentrations of sulfur and nitrogen (nitrogen reduces
the life of refinery catalysts) . The retorting process influences these
characteristics; that is , oils produced by The Oil Shale Corporation (TOSCO) ,
the Bureau of Mines, and the Union Oil Company processes would be
expected to have different viscosities.
Recycle coking with hydrostabilization is an effective means of shale-
oil upgrading (Figure 2). Except for nitrogen concentration, the
liquid product is acceptable to petroleum refineries and is amenable to
pipelining. Catalytic hydrodenitrogenation incorporated into the up-
grading process or performed at the refinery destination will produce
a premium feed stock with satisfactory nitrogen levels.
The products of coking and hydrostabilization are hydrotreated syn-
thetic crude, coke, fuel gas, and a small amount of hydrogen sulfide.
Wastewaters are expected from cooling tower blowdown and various unit
processes, containing dissolved materials (organic and inorganic) and
entrained solids. These will be consumed in spent shale quenching and
wetting. With proper construction of shale disposal sites, salt transport
by leaching and seepage will not occur.
16
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Crude
Shale
Oil
Preheat
800-850°F
Coker
Coke
800-850°F
Hash Still
665 °F
Bottom
Sediment
Waste Stream
Condensate
Fuel
Gas
T rr
Gos Processing
Gos- Liquid
Seporotlort
Hydrotreated
Synthetic
Crude
Spent Shale
Dis
Condenser
K>sal
Waste
Water
^r
•Cooler
Cooling Water
Treatment-Recycle
Water
Knock-out
Catalytic
Hydrostobllizotlon
Product
•Hydrogen
FIGURE 2 - SHALE OIL UPGRADING PROCESS
19
17
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DEWATERING OPERATIONS
Mining may permit migration of groundwater into the area of operation
and necessitate dewatering. Mine water of poor quality will serve in
meeting the large water requirement for dust control and spent shale
disposal. Requirements for cooling water will more than offset mine
water having low salinity.
In_ situ retorting will include preliminary formation fracturing. The
economics of large-scale production favor a contained nuclear detona-
tion for this purpose. Nuclear fracturing and in situ retorting will be
confined to the deeper, thicker oil shale deposits. Often the deposits
underlie a permeable, highly saline aquifer. Water wells to these
depths have yielded as much as 500 gpm. Total dissolved solids concen-
trations approaching 17,000 mg/1 have been reported. The volumes and
salinity will vary with depth and location in the tri-state area. If frac-
turing results in the migration of water from an aquifer into the retorting
zone, its quality may preclude disposal to even the poorest quality surface
streams in the area (see Table 1). Assuming the water contains no radio-
activity (see Section II, 5), it might be charged to a compatible subsurface
saline aquifer, subject to State permit and Federal policy.
MINERAL RECOVERY
Saline minerals in significant quantities are bedded in deposits of oil
shale which may be 1,800 feet below the surface and up to 900 feet
thick. The depth of the minerals relative to the surface suggests that
should the minerals be exploited, recovery will coincide with room-and-
pillar mining or in situ retorting operations. Dawsonite (a sodium
aluminum dihydrpxycarbonate), and nahcolite (a sodium bicarbonate)
appear to be the most economically attractive at this time. It is not
known whether industry will attempt to recover these minerals,
although research in the area is active in both industry and govern-
ment circles. The Department of Interior's policy concerning the
production of shale oil at the expense of another mineral resource is
also unclear at this time.
18
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Aboveground retorting with concomitant saline mineral recovery will
result in a spent shale residue with characteristics different from those
not recovering saline minerals. For example, the recovery of alumina
from dawsonite and soda ash from nahcolite may produce (depending on
the retorting process) a spent shale residue which has:
1. a smaller mean particle size, due to a fine crushing require-
ment;
2. an inorganic composition which has been chemically altered
because of higher process temperatures;
3. a particle surface devoid of elemental carbon;
4. a reduced leaching capability, since mineral recovery may
include acidic or alkaline leaching.
No information is available regarding the effects of weathering on the
residue. The limited volumes of the residue produced relative to retorted
shale and the uncertainty of recovery by industry make this an area of
lesser environmental concern.
It is anticipated that the process water from the leaching process will be
recycled in the saline mineral recovery operation. Waste leach water
from aboveground recovery will be consumed in makeup water for spent
shale disposal. Mineral recovery coincidental with in situ retorting may
result in waste leach water containing radionuclides that require special
treatment or disposal. The Bureau of Mines, Laramie, Wyoming, is
investigating the extraction of alumina from dawsonite-containing shale
in conjunction with in situ retorting. The studies may provide information
as to the characteristics and disposal of waste leach water, neither of
which is available at the present time.
RADIOACTIVE CONTAMINATION OF GROUNDWATER
In situ methods should be the last employed by industry at full-scale.
Operational problems including low oil recovery and the inability to con-
trol the direction of fire front have been experienced by the Bureau of
Mines in a field test at Rock Springs, Wyoming ,22 The Department of
19
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Interior's policy regarding partial recovery of an oil resource is unclear
at this time and will further influence in situ testing.
Contained nuclear devices have been proposed for formation fracturing
prior to inducing a fire front and retorting oil shale in place. One pur-
pose for their usage is to create extensive fracturing while holding the
cost per volume fractured to a minimum. Fracturing invites infiltration
of groundwater into the oil shale formation, otherwise impervious to
water. The possibility of venting radioactive gases into overlying
groundwater formations could result in contaminated groundwater. The
problem may be prevented by means of (1) precise pre-shot geologic and
hydrologic reconnaissance, and (2) the application of previous results
with contained nuclear detonations in similar rock types.
AIRBORNE EMISSIONS
Without precautionary measures, most of the industrial operations,
including drilling, blasting, crushing, conveying, retorting, and up-
grading , will result in air pollution through emissions of sulfur com-
pounds , nitrogen compounds, hydrocarbons, and dust. Mine regulations
regarding circulating air during blasting will impact dust emissions.
The geographic area is prone to temperature inversions that could
concentrate air pollutants in excess of State air quality standards.
Methods of controlling these emissions are currently in use for the
mining and oil refining industries: recovery of elemental sulfur; pre-
cipitators and enclosed systems for containing dust; and smokeless flares
for venting volatile hydrocarbons. The application of these control
methods to the oil shale industry is difficult to predict, since the wastes
requiring treatment will differ according to the processes selected for
commercial production. Elimination of airborne emissions can be
accomplished by closely monitoring the industry, implementing
applicable techniques, and enforcing air pollution legislation.
20
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SECTION VI
RESEARCH NEEDS
1. Surface water information regarding flows, quality, and commitments
indicates that the water requirements for an oil shale industry may exceed
the availability of uncommitted water and/or result in water quality degra-
dation sufficient to violate downstream agreements. In view of this, there
is a heightened interest in groundwater resources within the regional
confines of prospective oil shale development. Although data on ground-
water quality, pumping yields, location. and movement are available for
the Piceance Creek Basin of Colorado, similar information for the tri-
23
state area is incomplete. A study should be conducted emphasizing
the active industrial sites and USDI leases. The findings would permit
industry and government to evaluate the following groundwater
considerations for each site:
(a) availability of groundwater for process water,
(b) venting of radioactivity to overlying groundwater as a result of
nuclear fracturing,
(c) communication between fresh and saline groundwater aquifers
caused by nuclear fracturing,
(d) dewatering requirements for mining operations and in_ situ
retorting,
(e) continued groundwater seepage and grouting requirements at
abandoned sites of mining, subsurface spent shale emplacement, and
in_ situ retorting,
21
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(f) compatible salaquifers for injection purposes in the event
produced brines cannot be consumed as process water or treated, and
(g) annual variation in shallow groundwater table at the surface
site of spent shale disposal.
2. Prior to the establishment of mining and retorting facilities, base
line data are needed to assess the environmental impact of an oil shale
industry. Areas of interest to be studied include the following environ-
mental systems: surface water (including aquatic organisms), ground-
water, air, and terrestial species. The study should consist of the
following:
(a) preparation of monitoring guidelines,
(b) supplementation of existing monitoring stations to complete
the network,
(c) network testing under operating conditions,
(d) gathering of base line data, and
(e) preparation of a base line report.
Ultimately, base line conditions for each of the systems should be
established for the reaches of the upper Colorado River Basin which are
impacted by the oil shale resource. Initially, attention should be directed
to those specific sites where early activities by industry are indicated at
this time; for example, the Colony Development Operation site along
Parachute Creek, and the USDI lease sites.
3. A continuing assessment of total environmental impact is needed
throughout the course of oil shaje development, A part of the assessment
will be based on data obtained by operating the monitoring network and
measuring deviation from base line conditions. The final impact evalua-
tion will serve as a basis for EPA recommendations on future resource
development (for example, oil shale versus western coal) and to revise
research, development, and demonstration plans.
22
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4. EPA should conduct research necessary to prepare pollution control
guidelines for sites of oil shale mining and spent shale disposal. Mining
investigations should include groundwater protection from in_ situ frac-
turing, retorting, and abandonment. Studies of spent shales wetted with
waste process waters will be required. In addition, control and treat-
ability studies will be needed to prepare effluent limitations for in situ-
generated retort water, considered to be a point-source discharge.
5. The stability to mass movement of surface spent shale dumps poses
the most serious threat to the environment. It is imperative that industry
take every precaution to assure that no portion of the dump approaches
water saturation. To assure stability, continuous monitoring^ will be
required. As operational parameters change in working a lease site, the
resultant spent shales, each having a new set of characteristics, should
be thoroughly tested before disposal. Spent shale disposal sites will
require periodic examination during construction and following abandon-
ment . Specific parameters to be considered include: moisture versus
depth and position in the pile and in the dikes. stability to slide
(resistance to shear), and compression strength—all as a function of
ambient temperature and precipitation.
23
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SECTION VII
REFERENCES
Williams, F. E., et al. Potential Applications for Nuclear Explosives
in a Shale-Oil Industry. U.S. Bur. Mines, Report No. IC8425,
1969. 37 p.
Quality of Surface Waters of the United States, 1962. Part 9.
Colorado River Basin. U.S. Geological Survey Water Supply Paper
1945. 1964.
Compilation of Records of Surface Waters of the United States,
October 1950-September I960. Part 9. Colorado River Basin.
U.S. Geological Survey Water Supply Paper 1733. 1964.
Matzick, A., et al. Development of the Bureau of Mines Gas-
Combustion Oil-Shale Retorting Process. U.S. Bur. Mines,
Bulletin 635, 1966. 199 p.
Dineen, G. W. , J. S. Ball, and H. M. Thorne. Composition of
Crude Shale Oils . Industrial and Engineering Chemistry.
44(11): 2632, 1952.
Report on Economics of Environmental Protection for a Federal Oil
Shale Leasing Program. Colorado Department of Natural Resources,
Draft 1971. 57 p.
Environmental and Economic Report on Wyoming Oil Shale.
Wyoming Department of Economic Planning and Development,
Draft 1971. 57 p.
24
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8. Environmental Problems of Oil Shale. Utah Department of Natural
Resources, Draft 1971. 54 p.
9. Environmental Impact Statement for the Prototype Oil Shale Leasing
Program. U.S. Department of the Interior, planned for publication
in 1974.
10. Personal communication with the U.S. Bureau of Mines, Laramie,
Wyoming.
11. Water Pollution Potential of Oil Shale Retorting Residues from
Rainfall. Colorado State University. EPA Grant No. 14030 EDB
12/71. U.S. Government Ptg. Office, Washington, D.C.
12. Ward, J. C., G. A. Margheim, and G. O. G. Lof. Water Pollution
Potential of Spent Oil Shale Residues from Above-Ground Retorting .
(Presented at 161st ACS National Meeting, Los Angeles. March 29,
1971.)
13. Water Pollution Potential of Snowfall on Spent Shale Residues.
Colorado State University. U.S. Bur. Mines Grant No. GO111280,
directed by The Laramie Energy Research Center, Laramie,
Wyoming . Final report in print (June 1972) .
14. Kealy, C. D., and R. L. Soderberg. Design of Dams for Mill
Tailings. U.S. Bur. Mines, Report No. IC8410, 1969. 49 p.
15. Denson, K. H. , et al. Permeability of Sand with Dispersed Clay
Particles. Water Resources Research. 4(6); 1275, December 1968.
16. Personal communications with Colony Development Corporation and
the Union Oil Company.
17. Carpenter, H. C., H. W. Sohns, and G. W. Dineen. Oil Shale
Research Related to Proposed Nuclear Projects. (Presented at the
Plowshare Symposium on Engineering with Nuclear Explosives,
Las Vegas. January 14-16, 1970.)
25
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18. Hubbard, A. B. Method of Reclaiming Waste Water from Oil-Shale
Processing, (Presented at 161st ACS National Meeting, Los Angeles,
March 19, 1971.)
19. Montgomery, D . P. Refining of Pyrolytic Shale Oil. I and E C
Product Research and Development. 7(4): 274, 1968.
20. Policy on Disposal of Wastes by Subsurface Injection. Federal
Water Quality Administration. Communication 5040.10, October 15,
1970.
21. Hite, R. J. , and J. R. Dyni. Potential Resources of Dawsonite
and Nahcolite in the Piceance Creek Basin, Northwest Colorado.
Quarterly of the Colorado School of Mines. 62(3); 591, July 1967.
22. Burwell, E. L., H. C. Carpenter, andH. W. Sohns. Experimental
In Situ Retorting of Oil Shale at Rock Springs, Wyoming. U.S.
Bur. Mines, Technical Progress Report 16, June 1969. 8 p.
23. Coffin, D. L., et al. Geohydrology of Piceance Creek, NW,
Colorado. U.S. Geological Survey Atlas HA-370, 1971.
24. Carver, H. E. Conversion of Oil Shale to Refined Products.
Quarterly of the Colorado School of Mines. 59(3); 19, July 1964.
25. Nevens, T. D. Plant and Process for Production of Low Tempera-
ture Pumpable Oil from Oil Shale and the Like. U.S. Patent 3,018,243.
January 23, 1962.
26. Culbertson, W, J., Jr., et al. Plant and Process for the Production
of Oil. U.S. Patent 3,020,209. February 6, 1962.
27. TOSCO Details Costs for Oil Shale Process. Chemical and Engineering
News. May 26, 1969. 34 p.
26
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SECTION VIII
APPENDIXES
Page No.
A. National Environmental Policy Act, 1969 28
B. Retorting Process Descriptions 29
C. Characteristics of Spent Shale—Bench Study 34
D. TOSCO Shale Characteristics and Emplacement--
Pilot Study 36
27
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APPENDIX A
NATIONAL ENVIRONMENTAL POLICY ACT, 1969
Section 102(2) (C) of Public Law 91-190, National Environmental Policy
Act of 1969.
"The Congress authorizes and directs that, to the fullest
extent possible all agencies of the Federal Government shall
include in every recommendation or report on proposals for
legislation and other major Federal actions significantly
affecting the quality of the human environment, a detailed
'statement by the responsible official on—
11 (i) the environmental impact of the proposed action,
" (ii) any adverse environmental effects which cannot
be avoided should the proposal be implemented,
" (iii) alternatives to the proposed action,
" (iv) the relationship between local short-term uses
of man's environment and the maintenance and enhancement
of long-term productivity, and
" (v) any irreversible and irretrievable commitments of
resources which would be involved in the proposed action
should it be implemented.
"Prior to making any detailed statement, the responsible
Federal official shall consult with and obtain the comments of
any Federal agency which has jurisdiction by law or special
expertise with respect to any environmental impact involved.
Copies of such statement and the comments and views of the
appropriate Federal, State, and local agencies, which are
authorized to develop and enforce environmental standards,
shall be made available to the President, the Council on
Environmental Quality and to the public as provided by
Section 552 of Title 5, United States Code, and shall accom-
pany the proposal through the existing agency review
ti
processes "
28
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APPENDIX B
RETORTING PROCESS DESCRIPTIONS
BUREAU OF MINES GAS-COMBUSTION RETORTING PROCESS4
The retort in the gas-combustion process is a vertical, refractory-lined
shaft equipped with shale- and gas-handling devices (Figure 3) . Crushed
shale moves continuously downward through the retort vessel and is
preheated by rising, hot retorting products (gases) . Next it contacts
rising, hot flue gas, is retorted, and is left with a carbonaceous resi-
due . The shale continues downward and the sustained heat of the
process removes the carbon residue, leaving burned shale. Burned
shale transfers its heat to a rising stream of recycle gas. The cooled,
burned shale is mechanically discharged from the bottom of the retort
at a rate which controls the overall solids flow through the process.
Sustained heat is supplied to the process by introducing a mixture of air
and retort gas near the center of the retort. The rising gases and oil
vapors are cooled by incoming shale and are collected from the top of
the retort.
The gas-combustion process has been pilot-tested at three rates of
throughput: 6-, 25-, and 150-tons per day.
UNION OIL COMPANY RETORTING PROCESS24
The underfeed retort developed by Union is depicted in Figure 4. A
"rock pump" moves shale continuously in a vertical direction through
the retort. Ascending shale is preheated by a countercurrent stream
of hot flue gas forced downward by blowers. Continuing upward, hot
shale is retorted in a burning zone. Oil, noncondensable gases, and
cool flue gas are withdrawn from the bottom of the retort. Residual
carbon on the spent shale near the top is burned, generating hot flue
gas and shale ash. The ash spills into a disposal chute at the top.
29
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Row Shale
Shale
Preheating
Retorting
Combustion
Oil Mist
Separators
Oil-Lean
Gas
->• Blower
Recycle
Gas
Preheat
Gas
Processing
Dilution Gas
Air
Recycle Gos
Spent Shale
Receiver
Spent Shale
Quench
Spent Shale
Disposal
FIGURE 3 - BUREAU OF MINES GAS - COMBUSTION
RETORTING PROCESS4
30
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Overflow
Oil 8 Gas •*
Burned
Shale
FIGURE 4-UNION OIL RETORTING PROCESS24
31
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TOSCO RETORTING PROCESS25' 26' 2?
In the TOSCO retorting system, finely crushed, preheated shale and
hot ceramic balls are fed to a rotating pyrolysis drum. Direct contact
between the two heats the shale to retorting temperatures. Oil vapors
and gas are produced and are condensed in two stages to yield heavy
oil, crude shale oil, and noncondensable gases. A portion of heavy oil
is recirculated to the pyrolysis drum for thermal cracking. The
remainder is precooled, then atomized in the first condenser to remove
dust aerosol and assist in the condensation. Spent shale and warm
balls leave the pyrolysis drum and are screen separated. The warm
balls serve to preheat raw shale and are reheated to retorting tempera-
tures by burning noncondensable gases. Spent shale is quenched with
water prior to disposal. The original patents describe burning the
carbonaceous residue of spent shale in order to provide energy for
or 2A
heating the ceramic balls. ' The present indication is that this
method will not be practiced; however, it is included as an alternate
pathway in the process description. Figure 5.
32
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Raw Shale
Recycle
For
Thermal
Cracking
Warm Balls
Shale Preheoter
Hot Flue Gas
Preheated
Shale
(Consumed)
Spent Shale I
Rotating Pyrolysis
Drum
Oil Vapors
and Gases
Combustion Zone
Burned
Shale
Burned
Shale
Disposal
Partial
Condenser
Heat
Exchanger
Air or Water
(Consumed)
Recycle for
Condensing
Cooling Water
Treatment
Non-Condensible Gases
Gas Processing
Condenser
Condensed Oil
Oil Storage
FIGURE 5 - TOSCO RETORTING PROCESS25' 26' 27
(Alternate Pathway Dashed)
33
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APPENDIX C
CHARACTERISTICS OF SPENT SHALE—BENCH STUDY
11
1. Physical Properties
Bureau Mines
Geometric mean size, cm
Bulk density, g/ml
Solids density, g/ml
Porosity
Permeability, cm
Maximum particle size, cm
Minimum particle size, cm
0,205
1 . 44
2.46
0.41
3.46xlO~9
<3.81
>0.0008
TOSCO
0.0070
1.30
2.49
0.47
2.5xlO-10
<0.48
>0.0008
Union
(clinkered)
1.80
2.71
0.33
90.
30.
2 . Leaching Properties: Characteristics of a filtered solution obtained
by diluting to one liter a 250 ml aliquot of distilled water blended with
a 100 g sample of spent shale.
Concentrations (mg/1)
TDS
Conductivity 103° C
Sample pH (y mhos/cm) (mg/1) K+ Na+ Ca++ Mg++ HCO~ Cf SO~
Bureau Mines 7.8 1,495 1,090 72 225 42 4 38 13 600
Union 9.9 11,050 10,010 625 2,100 327 91 28 33 6,230
TOSCO 8.4 1.750 1,260 32 165 114 27 20 8 730
34
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3. Leaching Properties: Characteristics of a filtered solution obtained by
mechanically shaking one liter of distilled water with a 100 g sample of
spent shale for 5 minutes.
TDS
- , ,. ., -./loo/- Concentrations (mg/1)
Conductivity 103° C 6_ —
Sample pH (u mhos/cm) (mg/1) K+ Na+ Ca++ Mg++ HCOg Cl
Bureau Mines 7.8 1,320 970
TOSCO 8.4 1,640 1,121 10 206 102 31 20 6 775
4. Leaching Properties: Characteristics of leachate collected as a result
of percolating a two cm constant head of distilled water through a ten cm
diameter column containing 12.5 kilograms of TOSCO spent shale.
Volume of
Leachate
Sample (ml)
254
340
316
150
260
125
155
250
650
650
650
760
Cumulative Volume Cond .
of Leachate (ml) (y mhos/en
1,
1,
1,
1,
1,
2,
3,
3,
4,
254
594
910
060
320
445
600
850
500
150
800
560
78
61
43
25
13
9
7
6
5
4
4
3
,100
,600
,800
,100
,550
,200
,350
,820
,700
,800
,250
,850
Concentrations (mg/1)
n) Na+
35,200
26,700
14,900
6,900
2,530
1,210
740
500
Ca++
3,150
2,140
1,560
900
560
570
580
610
—
—
—
—
Mg++
4,720
3,720
2,650
1,450
500
580
470
540
soj
90,
70,
42,
21,
8,
5,
4,
4,
-
-
-
-
I C1~
000
000
500
500
200
900
520
450
—
—
—
—
3,080
1,900
910
370
200
140
140
80
35
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APPENDIX D
TOSCO SHALE CHARACTERISTICS AND EMPLACEMENT—PILOT STUDY
Description of TOSCO II Spent Shale Sample
Maximum Particle Size—<0.476 cm
Minimum Particle Size—>0. 00077 cm
Geometric Mean Size—0.0070 cm
Geometric Standard Deviation—3.27
Solids Density—2.49 g/cc
Bulk Density--!. 30 g/cc
Description of Spent Shale Emplacement
Approximately 68 tons of unweathered retorted shale were placed in a
pile measuring 80 feet long, 8 feet wide at the maximum depth of 2 feet,
and 12 feet wide at the surface. The shale was placed at a slope of
0.75%. The reader is referred to Ward, et al. for details of the facility
12
and the rainfall results.
Initially, the shale had a surface density (top 3 in.) of 86 lb/fT~ . Later
in the rainfall study the shale was compacted, whereupon the figure
became 101 Ib/ft . The average density below the surface remained
— 3 -\
unchanged at 55 Ib/ft . The surface density was reduced to 75 Ib/ft
following snowmelt and shale saturation.
36
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SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
1. Re port No.
3. Accession No.
w
; S. Report Date
POLLUTIONAL PROBLEMS AND RESEARCH NEEDS FOR AW OIL SFALE • o.
INDUSTRY
7. Author(s)
Pfeffer, F. M.
9. Organization
United States Environmental Protection Agency
Robert S. Kerr Environmental Research Laboratory
P.O. Box 1198, Ada, Oklahoma 74820
8. £ .'farisi, g Ofgsi.:istioti
Report Mo.
10. Pi&jectNo.
1U030 ETY
12. Sr user/a-- Organ' xtion
. Contract/GrantNo,
f. Typt .f Repui. and
Period Coveted
IS. Supplementary Notes
Environmental Protection Agency report number EPA-660/2-74-067, June 1974.
16. Abstract
The oil shale resources and surface stream drainage within the Green River Formation
of Colorado , Utah , and Wyoming are presented briefly . The aboveground retorting
processes of the Bureau of Mines , Union Oil Company , and The Oil Shale Corporation
are described , as are the physical and leaching characteristics of spent shale residues
derived from each process . Oil shale retorting in place (in situ) is summarized .
The area of major concern, stabilization of spent shale residues, is covered in detail.
Other areas of environmental concern are discussed: retort waste water , process water
from shale-oil upgrading, dewatering operations, mineral recovery, and contamination
of groundwater by radioactivity. Research needs are presented: a tri-state groundwater
report; environmental base line data; an assessment of total environmental impact;
pollution control guidelines; effluent limitations; and continuous EPA monitoring.
(Pfeffer-EPA)
17a. Descriptors
*Oil shale, *Waste dumps, *Slope stabilization, *Rainfall-runoff relationships, Erosion
control, Percolating water, Leaching, Vegetation establishment, Dewatering, Radioactive
wastes, Waste water (pollution), Waste water disposal, Waste water treatment.
l"b. Identifiers
^Research needs, Shale ash disposal.
17c. COW RR Field & Group
05B, 05C
18. Availabiliiv
15. Security Class.
"> (Repoj ;
"?. Sef-'iityC; ss.
2t, N&> of
Pages
2. Pri..B
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. O. C. 2O24O
Abstractor
FredM. Pfeffer
Environmental Protection Agency
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