United States	Industrial Environmental Research
Environmental Protection Laboratory
Agency	Cincinnati OH 45268
Research and Development EPA-600/D-82-283 Nov. 1982
SEPA
ENVIRONMENTAL
RESEARCH BRIEF
Overview of Environmental Impacts of Large-Scale Surface
Mining of Oil Shale: Piceance Basin, Colorado
Robert ,L. Lappi and Daniel I. Carey
Mathtech, Inc., Princeton, NJ 08540
Arnold H. Pelofsky
AER Enterprises, East Brunswick, NJ 08816
Edward R. Bates and John F. Martin
Industrial Environmental Research Laboratory, USEPA, Cincinnati, OH 45268
This paper discusses an EPA study on the major
environmental impacts of surface oil shale mining in the
Piceance Basin. Mine plans are developed for operations
producing at rates equivalent to 100,000 bbl/day, 400,000
bbl/day and 1,000,000 bbl/day. To facilitate analysis, a
specific site is analyzed; however, selection of the site dobs
not imply an endorsement of it. Environmental summaries
are presented for each of the three operations. With regard
to groundwater, much of the negative effect of surface
mining may be mitigable for smaller operations which
exploit only the upper rich oil shale strata.
Environmental impacts are generally less harmful with the
smaller-scale operations than with larger-scale operations.
Since economies of scale are not apparent for surface oil
shale mining, the need for detailed economic evaluation of
appropriate mine size is indicated.
Section 1
Introduction
This study helps to identify potential environmental
implications of large-scale surface oil shale mining in the
Piceance Creek Basin of Colorado. Three mine sizes were
selected for study: mines equivalent to 100,000 bbl/day,
400,000 bbl/day, and 1,000,000 bbl/day (15,800 m3/day,
63,200 m3/day, and 158,000 m3/day). Included in the
study are : mine site selection, development of preliminary
mining plans, determination of material movement
volumes associated with the mining plans for each level of
operation, determination of major environmental problems
expected, discussion of these problems and, where
appropriate, examples to consider for abatement.
Environmental Overview
Air, water, topography, wildlife, the health and safety of
workers, and the local social and economic structure will
be affected by the development of an oil shale industry.
Many effects will be similar to those caused by any mining
or petroleum development operation. The scale of
operations of an oil shale industry and its concentration in a
relatively small geographic area will create greater "local
impacts" than are associated with smaller resource
extraction and development operations.
The Piceance Basin, an area of approximately 2,300 square
kilometers (900 square miles), includes the Piceance and
Yellow Creek watersheds. The altitude in the basin ranges
from 1,500 to 2,600 meters (5,000 to 8,600 feet) above
mean sea level. The climate of the basin issemiarid with an
average annual precipitation of about 43 centimeters (17
inches). Mean annual precipitation increases with altitude
and ranges from about 29.5 to 64 centimeters (11.5 to 25
inches). About 60 percent of the precipitation occurs as
snowfall during November through March. Most of the
remaining precipitation results from spring and summer
thunderstorms.
The surface water and groundwater systems in the basin
are intimately related. Annual runoff from the basin is
about 19 x 106 cubic meters (15,600 acre-feet). About 80
percent of the surface streamflow is supplied by
groundwater discharge.1 Recharge to the aquifer system is
derived principally from spring snowmelt. Little, if any,
summer rainfall percolates to the groundwater aquifer
except in the alluvium. Runoff from the basin is affected by
evaporation, irrigation diversions, and consumptive use by

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crops and native vegetation. Stream-flow depletions from
irrigation are about 5.9 x 106 cubic meters/year (4,800
acre-feet/year).1 The periods of lowest flow occur in spring
and summer when irrigation diversions are greatest. The
estimated 7-day, 20-year low flow on Piceance Creek is 232
liters/second (8.2 ft3/s) below Ryan Gulch.
Irrigation return flows and groundwater discharge affect
the quality of surface water in the basin. The concentration
of dissolved solids ranges from less than 500 mg/l in the
upper reaches of Piceance Creek to more than 5,000 mg/l
in the lower reaches.' Water quality deteriorates in the
downstream direction due in part to groundwater discharge
from the Green River and Uinta Formations.
The groundwater system in the basin is complex but maybe
visualized as consisting of two principal aquifer systems
separated by the Mahogany zone (of the Green River
Formation) and locally interconnected by fractures and
faults. Groundwater flows from the margins of the basin
toward the north central part of the basin where it is
discharged in the Piceance and Yellow Creek valleys.
Recharge and discharge from the aquifer system are
estimated to average 32 x 10® cubic meters/year (26,000
acre-feet per year).1 Estimates of the volume of water in
storage range from 3 x 10® to 3.1 x 10'° cubic meters (2.5 to
25 million acre-feet), which represents a significant
potential resource.1
Sodium minerals in the aquifer below the Mahogany zone
are being actively dissolved by groundwater. The
Ma hoga ny zone i mpedes the flow of water between the two
aquifer systems, and large chemical differences have
developed. Water quality in the upper aquifer system
generally degrades with depth and in the direction of flow.
The water can be classified as sodium bicarbonate water.
The water contains moderate amounts of sulfate, and the
concentrations of chloride and fluoride are low. Concentra-
tion of dissolved solids averages about 950 mg/l, ranging
from 250 mg/l to more than 2,000 mg/l.1
The lower aquifer is classified as sodium bicarbonate
water, with concentrations of dissolved solids ranging
from 2,000 mg/l in the recharge areas to 30,000 mg/l in
the north-central area. This water generally has low
concentrations of calcium and magnesium (7.4 mg/l Ca,
9.5 mg/l Mg) and concentrations of fluoride exceeding 40
mg/l in the north-central part of the basin.1
Alluvial aquifers as thick as 43 meters (140 feet) and
generally less than 0.8 kilometer (0.5 mile) wide are
sources of water in the major stream valleys. Alluvial water
quality is similar to the upper aquifer.1
Water quality and availability is a major concern in the
Piceance Basin, particularly if the development of an oil
shale industry is to proceed. Because the groundwater
aquifers are the source of most streamflow and irrigation
water in the basin, degradation of groundwater quality and
disruption of aquifer systems is a major environmental
concern. Underground mining and retorting operations
present particular challenges for the control of pollutants,
while both surface and underground operations may
require significant pumping for dewatering, thereby
lowering groundwater levels. Although shale developers
are currently planning for zero discharge to streams, the
potential exists for pollution of surface water by
suspended solids, oil and grease, nutrients, toxic
substances and microbial contamination.
Solid waste disposal and surface storage of spent and raw
shale may provide sources of air and water pollutants
through fugitive dust emissions, surface runoff, and
leaching. Permanent surface disposal of solid wastes will
affect local topography which may be difficult to stabilize
and revegetate. Although revegetation has been achieved
on spent shale in a number of studies, the issue of whether
continuing maintenance will be required is not settled.
Waste streams associated with a shale industry may
contain hazardous trace substances. In general, little is
known about the hazards of shale-related waste streams.
However, minor amounts of radioactivity will be released to
the atmosphere during mining and processing, and a trace
amount of radon gas will be released directly.
Noise levels during plant construction and operation,
mining, and operation of supporting activities could be
locally high if not properly controlled.
With regard to surface mining and retorting, ifthe operation
is designed with proper consideration for the total
economic, environmental, and social system, there is
reason to believe that existing technologies for the control
of residuals will perform adequately. Perhaps the greatest
disruption to the ecology of the Piceance Basin would occur
as a result of the large growth in the local human population
supporting the shale industry. The outdoor recreational
activities of this population may, in itself, significantly alter
the environment of the basin.
Section 2
Mine Location
Introduction
In order to report on the magnitude of environmental
disturbance which would be created by surface mining, it
was decided to select an actual site within the basin for
analysis. The advantage of this approach is that volumes of
overburden and oil shale necessary to achieve oil
production, and the accompanying environmental analysis
would be based on actual conditions in the basin. Selection
of an actual location facilitated this study but should not be
viewed as a recommendation or endorsement for
development at this particular site.
Procedure and Site Selection
Initially, outcrop or near-outcrop locations were considered
the most likely sites for study. No such sites capable of
supporting a mine as large as 1,000,000 bbl/day were
located. In all cases observed, including the Suntech site,2
the reserve base was limited because of a rapid deepening
of reserves from the outcrop. The Suntech study,2 which
was performed for the Bureau of Mines, produced resource
maps which were used to develop several cross sections of
the basin.
Analysis of the cross sections indicated a relatively
favorable stripping ratio location approximately 11
kilometers (7 miles) northeast of the center of the basin
(Figure 1). This location is characterized by a gentle
anticline of the underlying oil shale beds coincident with
apparent erosion of overburden.
2

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White
River
Ranaely
Yellow
Creek
Sun Oil
p;Site
Meeker
Sun Oil
Disposal
Site f
r
Study Site
Rio Blanco Co
Douglas
Creek
C-br-TTV
¦u-j*
Piceance Creek Basin
Garfield Co.
Piceance
Creek
Rio Blanco Co.
Blanco
Garfield Co
Garfield
Parachute
Garfield Co.
Mesa Co.
Debeque
Colorado /River
rand Valley
oi u u jyyjpt i t g
0 Meters 25,000 m
80,000'
Figure 1. Area map.
Permanent storage of initial pit material appears to be
available at a distance of approximately 7 kilometers (4.3
miles) north of the mine site. Whether permanent storage
is appropriate is questionable. If not, initial pit material
could be temporarily stored above ground near the mine
site.
The study area shown in Figure 1 over which the
overburden remains constant or increases onty gradually
consists of approximately 130 square kilometers (50
square miles). Underlying this area is an oil shale thickness
of 300 meters (1,000 feet), with an average grade of 85+
liters of oil per tonne (20+ gallons/ton (excluding leaner
strata). This indicates a reserve base of nearly 50 billion
barrels (7.9 billion m3), which is sufficient to support a
1,000,000 bbl/day mine for 140 years.
Elevation
feet
Because of the site's location in and near the Piceance
Creek valley, water is assumed to be available from the
underground aquifers. The site is, however, more suitable
to an effective water control plan because of its proximity to
Piceance Creek.
Site Characteristics
Overburden/Oil Shale Characteristics
Profiles of the selected site within the study area were
prepared both across and along the site (cross sections CC
and DD, Figures 2 and 3). Typical of the basin, the profiles
show overburden, the Mahogany oil shale stratum, a thin
oil-less zone (B-groove), and 11 underlying oil shale strata
alternately rich and lean (R-6 to R-1 and L-5 to L-1). Table 1
lists the range of thickness of the overburden and rich oil
shale strata in the mining area. Table 2 lists the range of oil
shale grades (Fisher assay) for the Mahogany and R-strata.
Site Hydrology
The study site lies north of Piceance Creek opposite Tract C-
b. Both the upper and lower aquifers may be intersected by
the mining pit, and mine dewatering will have a significant
impact on the hydrologic regime. Local effects of mining on
the groundwater system would be the most significant
hydrologic impact of the operation.
Dewatering flow rate estimates range from 5,700
liters/minute (1,500 gpm) at Tract C-b,3 to 57,000
liters/minute (15,000 gpm).1 Groundwater quality and flow
have not been clearly established for the basin, however,
and the figures cited in this study are principally for
purposes of illustrating potential groundwater impacts
related to surface mining. If the latter estimates are true,
excess water will be produced. Several disposal alternatives
are possible: (1) reinjection, perhaps in northern, more
brackish areas of the aquifer; (2) transfer to areas of water
shortage; (3) treatment and disposal; or (4) a combination of
the above.
Dissolved solids concentrations of the mine water should be
less than 1,000 mg/l for the upper aquifer and less than
5,000 mg/l for the lower aquifer.1 The mine site will be
dewatered by drawing down the site aquifers with
pumping of perimeter wells. Mine discharge will not
Elevation
meters
7500'
2250 m
7000'
2100 m
B-Groove
6500'
1950 m
Overburden
Mahogany
1800 m
r-flu
5500'
1650 m
5000'
1500 m
4500'J
1350 m
7010 m
23,000'
Figure 2. Cross section cc of study site.
3

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Elevation
feet
7010 m
23,000'
5500'-
B-Groove -
Overburden
6000
Mahogany
5500'
5000'
i—y—¦f-
L-2 L-1
4500
4000'
B-Groove
7000'
6500'
Overburden
Mahogany
6000'
5500'
5000'
4500
14,021 m
46,000'
Overburden
'Mahogany 	
			 B-Groove.
Elevation
meters
r1950 m
1800 m
1650 m
1500 m
1350 m
1200 m
7010 m
23.00CT
2100 m
1950 m
1800 m
1650 m
1500 m
1350 m
14,021 m
46,000'
¦2100 m
-1950 m
¦1800 m
5000'
1500 m


4500'
1350 m
20,955 m
68,750'
Figure 3. Cross section dd of study site.
contact raw shale rubble. Treatment of all or part of the
excess water would allow utilization for a variety of
purposes and may be the least disruptive method to obtain
water to meet the demands of an oil shale industry,
agriculture, and an expanded population. Costs of this
water development strategy have been estimated to be
$0.02 to $0.50/cubic meter ($20 to $600 per acre-foot)
depending on the level of treatment required.4
Optimal treatment levels for mine water, and gas
condensate and retort water are a function of mine water
production, the retort process, and end use. Both solid and
liquid residue streams should remain segregated to ensure
economical and environmentally sound treatment.
Following removal of organics and reduction in inorganic
concentration levels, process waste water quality would be
comparable to mine water.
Table 1. Range of Thickness of Strata at Mine Study
Site2
Max. Thickness	Min. Thickness
Stratum	Meters	Meters
Overburden
375 (1,230 ft)
101 (330 ft)
Mahogany
64 (210 ft)
43(140 ft)
B-groove
49 (160 ft)
8 (25 ft)
R-6
61 (200 ft)
37 (120ft)
R-5
73 (240 ft)
66 (215ft)
R-4
49 (160 ft)
27 (90 ft)
R-3
37 (120 ft)
15 (50 ft)
R-2
30 (100 ft)
18 (60 ft)
R-1
87 (285 ft)
27 (90 ft)
4

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Table2. Range of Oil Shale Strata Grades at Mine
Study Site2 (Fisher Assay)
Maximum	Minimum
Stratum
liters/tonne
gal/ton
liters/tonne
gal/ton
Mahogany
117
28
92
22
R-6
100
24
92
22
R-5
133
32
58
14
R-4
125
30
92
22
R-3
92
22
75
18
R-2
125
30
92
22
R-1
108
26
75
18
Section 3
Three Surface Mines
Introduction
This section postulates three surface mines capable of
producing oil shale at 100,000, 400,000 and 1,000,000
bbl/day, respectively. They are described as Case 1, Case 2,
and Case 3.
Assumptions which are common to all three cases are:
1.	The entire mining area is adequately represented by
cross sections CC and DD (Figures 2 and 3).
2.	Data on thickness, depth, and grade of all strata are
primarily from the Suntech report.2
3.	B-groove stratum above the R-6 is mined selectively
as waste on the same bench level as the bottom half of
the Mahogany stratum.
4.	Mining recovery (within the pit) of oil shale is 100%
arid shale oil recovery is 100% Fisher assay.
5.	Initial overburden removed to open the pit is
permanently stored off-site or temporarily stored near
the mine.
6.	Mining benches are 30.5 meters (100 feet) high and
61 meters (200 feet) wide.
7.	Primary crushing of oil shale occurs at the bottom of
the pit.
8.	Unimpeded aquifer flow rate through dewatering is
38,000 liters/minute (10,000 gpm), treated mine
water is reinjected, and there is zero discharge to
surface streams.
Case 1—100.000 BBL/Day Surf act Min§
Specific assumptions for Case 1 used in developing a
mining plan are:
1.	Truck and shovel mining is assumed because it is the
current predominant mining method for deep
deposits.
2.	Pit floor dimensions are 244 meters (800feet) (in the
direction of mining) by 335 meters (1,100 feet).
Oil Shale Strata Mined
Overall pit dimensions must be larger for a deeper pit which
requires that both overburden and ore must be hauled
farther and lifted higher. Haulage capital and operating
costs, which are major cost components of deeppit mining,
increase with depth. Because deeper pits require more
benches, relatively more ore is lost under the benches;
therefore, the effective stripping ratio (the ratio of actual
overburden to ore) relative to the in-place ratio of
overburden to ore is higher and total resource recovery is
lower for deeper pits than for shallow pits.
Surface mining upper strata does not preclude using
underground methods for lower strata. The incremental
cost of mining deeper reserves by strip mining must be
compared to the cost of development by underground
methods which include modified in-situ and underground
mining. The cost of underground mining also increases
with depth, but probably at a slower rate than surface
mining.
For these reasons, detailed economic evaluations should be
made to determine whether surface mines to the bottom of
the oil shale strata are appropriate. This study assumed for
both tbe 100,000 and 400,000 bbl/day (15,800 and
63,200 mVday) study mines that only the Mahogany and
R-6 strata are surface mined. The bottom of the R-6 makes a
convenient cutoff point because it abuts the low-grade L-5
stratum which might require a difficult wasting operating
for a layer of interburden ranging in thickness from 18 to 60
meters (60 feet to 200 feet) and averaging 46 meters (150
feet).
Mining Plan
Figures 4 and 5 show plan and section views of a
hypothetical mature truck and shovel pit capable of
producing 100,000 bbl/day (15,800 mVday). After the
initial pit is opened, overburden is mined on benches, 30.5
meters high, 61 meters wide (100 feet high, 200 feet wide)
carried along the bench, and backstacked in the original
sequence. Oil shale is carried along the bench to chutes for
transport to the bottom of the pit where it is subjected to
primary crushing. Then it is loaded on trucks and hauled out
of the pit to retorting facilities assumed to be 1,6kilometers
(1 mile) from the pit. B-groove material, which is
interburden, is conveyed to the bottom of the pit and used to
form the permanent pit floor. Spent shale is returned to the
pit directly from the retort by truck, dumped, wetted, and
compacted. Table 3 lists pertinent annual mining statistics
for the mature operation.
The effective stripping ratio of 4 tonnes waste/tonne oil
shale for this operation is primarily a function of the size of
the pit, which was designed to remain in low overburden
and to maintain short haul distances. However, the
narrowness of the pit, from the standpoint of resource
recovery, is inefficient because relatively large amounts of
oil shale are left under the development benches as the
mine advances. A wider pit, even at the cost of significantly
increasing average overburden height, because of a
proportionately smaller amount of ore being lost under the
mine benches, would reduce the stripping ratio (see Case
2).
Pit width optimization is a matter of balancing benefits of
decreasing the stripping ratio against the increased hauling
costs required for a wider pit. Figure 2 shows the outline of
all three study mines on section CC.
Mining Equipment Required
Table 4 estimates the major mining equipment required for
the Case 1 mine.
B

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*
1.6 kilometers To Retort
Flat plateau for dumping and spreading spent shale
244
335 m
Mining
Advance
meters	I
0	1S0m	*
1	'i ' ¦¦ 1	"
0 500'
feet
Figure 4. Plan view of mature pit — Case 1.
Other support equipment will include scrapers, graders,
front-end loaders, and miscellaneous vehicles. Fuel
consumption of the support equipment is estimated to be an
additional 1,900 liters/hour (500 gallons/hour). In
addition, approximately 53,000 tonnes/year (58,000
6
tons/year) of ammonium nitrate and fuel oil (ANFO) are
required for blasting.
Reclamation
Backfilling the pit area would be performed by selective

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Overburden
Mahogany Layer
B-Groove
R-6 Layer
Haul Road ^ ^ — —

meters
0	150 m
1	'i ¦¦111 M
0	500'
feet
Figure 6. Mature pit crocs section — Case 1.
Table3. Mining Statistics - Case 1, Mature Pit
Overburden — thousand tonnes/day (thousand tons/day)
Interburden — thousand tonnes/day (thousand tons/day)
Total Spoil — thousand tonnes/day (thousand tons/day)

646
13
659

(711)
(14)
(725)
Oil Shale — thousand tonnes/day (thousand tons/day)
Oil Shale — average grade, liters/tonne (gallons/ton)
Shale Oil — thousand bbl/day (thousand m3/day)

161
98.6
100
(178)
(23.6)
(15.8)
Stripping Ratio — tonnes spoil/tonne oil shale



4:1

Mining Advance — meters/year (feet/year)
Surface Disturbance — hectares/year (acres/year)

432
62

(1420)
(153)
Table4. Case 1, Major Mining Equipment





Type Size
Number
Required
Power
D-diesel
fuel
E-electric

Diesel Fuel
Consumed
(liters/hr)
(gallons/hr)
Shovels 23 cubic meters
(30 cubic yards)
15
E

n/a

End-dump Trucks 155 tonnes
(170 tons)
150
D

18,200
4,810
Bulldozers 3x10s joules/
second
(740 horsepower)
50
D

2,800
740
Rock Drills 25 centimeters
(9.75 inches)
6
E

n/a

placement of the overburden and compacted spent shale in
the original strata sequence. All spent shale would be
returned to the pit. The shale would be moistened and
compacted for cementation in layers about 46 centimeters
(18 inches) thick. The return of the compacted spent shale
to its approximate original position should provide a
relatively impermeable zone between the upper and lower
aquifer systems. In this sense, the groundwater system
would be returned to pre-mining conditions. This
restoration is, of course, contingent upon the impermeability
of the compacted spent shale to leaching. Laboratory- and
field-compaction tests on spent shale indicated that
permeabilities as low as 10"7 cm/s can be obtained.6
Others8,7'8 have found that spent shale cannot always be
made impermeable. Returning the spent shale to its
original stratigraphic position, juxtaposed to the Mahogany
zone and associated Bird's Nest aquifer, would place much
of the waste material — possibly including solid residuals,
catalysts, chemicals, sewage and refinery-type sludge —
below the static water table. Given enough time, the spent
shale would become saturated. Leaching will occur
through this material relative to the degree or permeability
and the significance of occurrence of fracturing or other
conduit formation.

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Miscellaneous solids residuals, such as catalyst and
chemicals, sewage, and sludges, may be proauced at a rate
of about 5 percent that of spent shale, or about 6,850
tonnes/day (7,550 tons/day). Products in this waste
stream from which no secondary benefits can be derived
will have to be disposed of in conformance with federal and
state regulations. One possibility may be to isolate the
material between layers of compacted spent shale in the
pit.
Topsoil salvaged during the mining operation would be
placed on reclaimed land to be revegetated.
Continuous backfilling and reclamation during mining
operations will minimize material exposure times. All
material will be returned to the pit with the exception of
122,000,000 cubic meters (160,000,000 cu yds) of
overburden removed during the initial pit development.
Because waste and spent shale will occupy more volume
after disturbance, reclaimed land will be higher than the
original contour. Side slopes of the reclaimed land surface
must be planned so that surface runoff is controlled tc
minimize leaching of the spoil and erosion of the surface.
Two alternative methods are available for filling the final
pit. First, the initial pit overburden can be stored in the area
of the initia I pit a nd at the end of mining be transported to the
final pit for fill. Along cross section DD, the mine life will be
45 years and the final pit will be 21 kilometers (13 miles)
from the initial pit. The advantages of this approach are
short haul distances for development of the pit and possible
postponement of reclamation costs. Both advantages have
a favorable financial impact in the early stages of surface
mining. A disadvantage is the requirement for much longer
haul distances to transport the initial overburden to the
final pit. This disadvantage might be somewhat mitigated
by the availability of hauling equipment upon cessation of
mining. The second method is to permanently store the
initial overburden about 11 kilometers (7 miles) from the
site on rugged terrain and withhold a portion of overburden
spoil, and as mining approaches the area of the final pit,
stockpile the spoil and use ittofillthefinalpit. Because both
overburden and spent shale swell, adequate amounts of
spoil will be available. This alternative method would
decrease the distance to haul fill for the final pit, but it may
require additional trucks.
Leaving a typical open pit mine, after covering backfilled
spent shale with adequate overburden, would require
careful planning to ensure that the final configuration of the
reclaimed pit has minimal adverse impact on groundwater
levels, quantity, and quality in the basin.
Water Management
Table 5 lists the inorganic salt concentrations of the upper
and lower aquifers and compares the salt concentrations of
these aquifers with the TOSCO wastewater. If the
wastewater from the TOSCO process were treated to
remove organic contaminants (and possibly some metals
and inorganic contaminants), the remaining water probably
could be reused or reinjected Into the lower aquifer. Figure
6 depicts this water management plan. Within economic
restraints, this plan suggests that wells be drilled into the
aquifers in such a manner that water is allowed to enter the
pit, through fractures in the walls, only in quantities
sufficient to maintain low dust levels. If the remaining water
Table5. Water Quality: Upper and Lower Aquifers and
TOSCO Wastewater, (mg/l)
Aquifer1

Upper
Lower
TOSCO8
Inorganics
(mean values)
Wastewater
Ca
50
7.4
280
Bicarb
550
9,100
100
Carbonate
n/a
n/a
360
CI
16
690
570
TDS
960
9,400
3,100
Fl
1.4
28
<1
Mg
60
9.5
100
Na
210
3,980
670
Sulfate
320
80
850
K
1.5
11
<1
were treated to remove salts, it could be sold to process
developers or reinjected into the surrounding aquifers to
help maintain groundwater levels.
If the assumed aquifer flow rate of 38,000 liters/minute
(10,000 gpm) is realized, and if oil shale processing requires
3 barrels of water per barrel of shale oil produced (a high
estimate), the aquifer water would be sufficient to provide
the required water for 100,000 bbl/day of shale oil, and
minimal use of surface water would be required by this
operation.
Dust
A recent EPA report titled "Environmental Perspective on
the Emerging Oil Shale Industry"9 lists five estimates of
atmospheric particulate emissions from oil shale mining. In
terms of tonnes of dust per tonne of oil shale mined, these
estimates vary from 1.2 x 10~4 to 6.3 x 10~3, a very wide
range.
As a source of dust generated during mining and
processing, limestone is a relatively high producer. EPA has

Organic Sludge
Sludge is
buried in
spent shale
Spent
-» Shale
Wetting
Cementation
and
Oust Control
(to remove organics)
o 6

Treatment
Irrigation
Surface
Mine
Potable
Water
Collection
Manifold
Oil Shale
Complex
Waste Water
Treatment
\
Well
Figure 6. Water management plan.
8

-------
studied limestone emissions, reported in "Source
Assessment: Crushed Limestone, State of the Art"10 and
published the data shown in Table 6 relating mass
particulate emissions from limestone to various stages of
mining and processing operations. Total limestone dust
emissions of 3.5 grams/tonne are equivalent to 3.5 x 10~8
tonnes of particulates per tonne of ore mined.
Assuming similar dusting characteristics for oil shale
(which is dolomitic marlstone), Table 7 is constructed.
Predicated on the above assumption, a 100,000 bbl/day
surface mine would emit 2.13 tonnes (2.35 tons) of
particulate dust per day with partial controls (primarily on
roads). The principal source of dust would be vehicular
traffic between the pit floor and plant and reclamation
areas.
Environmental Summary — Case 1
Impacts on air quality at the mine site could resultfrom dust
generation and gaseous emissions from mining equipment.
Data from comparable limestone operations were
extrapolated, with the associated degree of uncertainty,
and indicate particulate dust emissions of 2.13 tonnes per
Table 6. Mass Emissions from Various Operations in
the Crushed Limestone Industry
Particulates
(grams particulate/
Operation	tonne limestone)*
13.5 tonnes/day
8.1 tonnes/day
(3.7 tons day)
(8.1 tons/day)
(0.8 tons/day)
(14.9 tons/day)
(8.9 tons/day)
Drilling
0.11
Blasting
0.075
Loading at the quarry
0.0015
Vehicular traffic
2.3
Primary crushing
0.56
Primary screening
0.0016
Secondary crushing
0.14
Secondary screening
0.0009
Conveying
0.32
Stockpile
nil
Unloading at stockpile
nil
Total
3.5
day (2.35 tons/day). The principal source of dust results
from vehicular traffic. Fuel consumption by mining and
support equipment is estimated to be 550,000 liters
(145,000 gallons) of diesel fuel per day. Based on emission
data (Table 8) this would result in the following diesel
engine emission rates per day:
SO2	3.4 tonnes/day
NO2	7.4 tonnes/day
Aldehydes	0.7 tonnes/day
and Ketones
Total
Hydrocarbons
Total
particulates
The 100,000 bbl/day operation may not have a large impact
on water resources, but drawdown of groundwater in the
vicinity of the pit would result from dewatering. Oil shale
processing water requirements (3 bbl water/bbl shale oil or
33,100 liters (8,750 gallons) per minute water) would be
provided by the dewatering operation which produces
38,000 liters/minute (10,000 gpm). Excess water would be
treated and sold or reinjected, with zero discharge to
streams. Comparison of salt concentrations in TOSCO
wastewater and aquifer water indicate that it may be
possible to treat the process wastewater and reinject it into
the lower aquifer.
Surface environmental impacts would be minimized by
compacting spent shale and residual solids in the pit
beneath replaced overburden. Continuous backfilling and
reclamation, with topsoil material replacement, would limit
disturbed surface exposure to about 62 hectares (153
acres). Overburden from initial pit development (122,000,
000 cubic meters) (160,000,000 cubic yards) would be
stored and revegetated off-site, with possible subsequent
transport of some of the material to fill the final pit.
During the 45-year mine life, 4,050-8,100 hectares
(10,000-20,000 acres) would be altered by mining and
ancillary activities. This could have a large impact on
zoological species in and adjacent to the area. The
significance of this impact beyond relocation of local
populations is unknown and requires further study
Vegetative disruption would be temporally shorter, and
*Parts per million or pounds per million pounds.
Table7. Estimated Dust Emissions from Various Oil Shale Surface Mining Operations-Case 1
Rock Processed
Particulate
Dust Emissions
Operation
(000 tonnes/day)
(000 tons/day)
(tonnes/day)
(tons day)
Drilling
820*
903
0.09
0.10
Blasting
820*
903
0.06
007
Loading at the pit
820*
903
nil
nil
Vehicular traffic
820*
903
1.89
2.08
Primary crushing
161**
178
0.09
0.10
Primary screening
161**
178
nil
nil
Secondary crushing
-t
-
-
-
Secondary screening
-t
-
-

Conveying
-t
-
-
-
Stockpile
-+
-
-
-
Total


2.13
2 35
•Total rock mined-
**0il Shale only.
tRetorting process
-overburden and oil shale,
-not applicable to this study.
9

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Table 8. Typical Diesel Fuel Emissions"
		grams/gram diesel fuel
S02	0.0075
NOn	0.0165
Aldehydes arid Ketones	0.0016
Total Hydrocarbons	0.030
Total Particulates	0.018
Diesel = 820 grams/liter (S.G. = .82)
native or introduced species should adapt to the reclaimed
area within a reasonable time.
Vehicular energy requirements would be 0.035 bbl diesel
fuel/bbl shale oil. Approximately 1.5 kg (3.3 lb)of ANFOper
barrel of shale oil would be required for blasting.
Case 2 — 400,000 BBL/Day Surface Mine
Case 2 is a 400,000 bbl/day (63,200 m3/day) surface mine
in the study site area. In addition to the general
assumptions made for all study cases, the specific
assumptions for Case 2 are:
(1)	Truck or enclosed conveyor and shovel mining.
(2)	Pit floor dimensions are 245 meters (800 feet) by
1,435 meters (4,700 feet).
(3)	Mahogany and R-6 oil shale strata only are mined.
Except for the option of enclosed conveyors instead of
trucks. Case 2 is an extension of Case 1 to a larger scale.
The life of the Case 2 mine in the study area is 35 years.
Table 9. Mining Statistics-Case 2, Mature Pit
Mining Plan
The mining plan for Case 2 is substantially the same as for
Case 1. Overburden is mined on 61-meters wide (200-ft.)
benches, carried along the benches, and backstacked in the
original sequence. Oil shale is carried along the bench by
trucks or conveyors to chutes where it is transported to the
bottom of the pit for primary crushing (for which the
requirements are greater for the conveyor operation). Next,
it is loaded on trucks or conveyors and hauled out of the pit
to the retort. As in Case 1, B-groove material is conveyed to
the bottom of the pit and used for the permanent pit floor.
Spent shale is returned and dumped, wetted and
compacted on the pit floor. Table 9 lists pertinent an'nual
mining statistics for the mature operation.
The stripping ratio of 3:1 for Case 2 is 25% less than Case 1,
notwithstanding an increase of approximately 10% in
overburden thickness (see Figure 2) because of increased
resource recovery associated with the wider Case 2 pit.
Mining Equipment Required
Table 10 estimates the major conventional mining
equipment required for the Case 2 mine.
The number of shovels per unit for shale oil output is less for
Case 2 than for Case 1 in proportion to the stripping ratios
for the two cases. On the other hand, the number of trucks
per unit of shale oil for the truck haulage operation is
greater because of longer haul distances, in spite of the
25% reduction in stripping ratio.
Overburden — thousand tonnes/day (thousand tons/day)
1,855
(2,040)
Interburden — thousand tonnes/day (thousand tons/day)
47
(52)
Total Spoil — thousand tonnes/day (thousand tons/day)
1,902
(2,092)
Oil Shale — thousand tonnes/day (thousand tons/day)
652
(719)
Oil Shale — average grade, liters/tonne (gallons/ton)
97.4
(23.4)
Shale Oil — thousand bbl/day (thousand mVday)
400
(63.2)
Stripping Ratio — tonnes spoil/tonne oil shale

3:1
Mining Advance — meters/year (feet/year)
562
(1,843)
Surface Disturbance — hectares/year (acres/year)
153
(378)
Table 10.
Case 2, Major Mining Equipment





Type
Size
Number
Required
Power
D-diesel
fuel
E-electric
Diesel Fuel
Consumed
(liters/hr)

(gallons/hr)
Shovels
23 cubic meters
(30 cubic yards)
45
E

n/a

End-dump
Trucks
or
Conveyors
155 tonnes
(170 tons)
650
D
78,700

20,820




n/a

Bulldozers
3x10® joules/
second
(740 horsepower)
220
D
12,500

3,305
Rock Drills
25 centimeters
(9.75 inches)
20
E

n/a

10

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Support equipment shows fuel consumption increased an
additional 8,300 liters/hour (2,200 gallons/hour). Approxi-
mately 164,000 tonnes/year (180,000 tons/year) of ANFO
are required for blasting.
Reclamation
Reclamation for Case 2 would be the same as Case 1 except
on a larger scale. The amount of initial pit overburden which
must be stored permanently or temporarily is 279,000,000
cubic meters (336,000,000 cu yds). The same options
regarding the final deposition of the initial pit overburden
are available for Case 2 as for Case 1.
Water Management
Aquifers intercepted by the pit in Case 2 are the same as
those for Case 1. The water management plan would be
similar to Case 1 (Figure 6). Water usage requirements for
the 400,000 bbl/day operation would, however, be 132,000
liters/minute (35,000 gallons/minute) based on 3 bbl of
water /bbl of shale oil. Groundwater pumping in addition to
the pit dewatering operation may be required to meet the
water needs. Since the quality of the waters will be similar
to Case 1, post-use treatment and disposal would be the
same.
Dust
Table 11 lists estimated dust particulate emissions for the
Case 2 truck haulage operation. These estimates are based
primarily on the methodology used in Case 1 (Table 2) with a
significant adjustment for dust generated by vehicular
traffic because of that source's predominant proportion of
total emissions generated. If the methodology of Case 1
were adhered to, the increase in dust from vehicles for Case
2overCase 1 would beafactorof 3:1. Because of the larger
pit and longer haul distances, Case 2 requires an
estimated 650 trucks compared to Case 1 's requirement of
150, a ratio of 4.3:1. It is reasonable to assume that dust
generated by vehicles will depend more directly on the
number of operating vehicles than on the production
tonnage. Therefore, vehicular dust for Case 2 was assumed
to be 4.3 times that for Case 1. An estimated 8.97 tonnes
per day (9.87 tons/day) of dust particulates would be
emitted, of which 91% is attributable to vehicular traffic.
Because of substantial reduction in vehicular traffic,
enclosed conveyor haulage of shale and overburden
produces significantly less dust than truck haulage. We
have assumed a reduction of 85% in the emission factor
listed in Table 6 for vehicle-generated dust for the
conveyor haulage option, and added a conveyor-mining
emission source.'0 Table 12 lists the estimated particulate
dust emissions for the Case 2 enclosed conveyor option.
Summary — Case 2 Environmental Impacts
Air quality impacts of the 400,000 bbl/day operation were
estimated usinjg substantially the techniques of Case 1.
Dust emissions for the 400,000 bbl/day truck haulage
operation are estimated to be 8.97 tonnes/day (9.87
tons/day). Using enclosed conveyors for haulage instead of
trucks reduces particulate emissions 72% to 2 54
tonnes/day (2.80 tons/day).
For the truck haulage operation, fuel consumption by mining
equipment is estimated to be 2,390,000 liters (630,000
gallons) of diesel fuel per day. Based on the emission data of
Table 8, this would result in the following diesel engine
emission rates per day:
S02
NO*
Aldehydes
and Ketones
Total
hydrocarbons
Total
particulates
14.7	tonnes/day
32.3 tonnes/day
3.1 tonnes/day
58.8	tonnes/day
35.3 tonnes/day
(16.2 tons/day)
(35.5 tons/day)
(3.4 tons/day)
(64.7 tons'day)
(38.9 tons/day)
Emissions from diesel-operated equipment would decrease
by 79% for the enclosed conveyor operation because
primary haulage equipment would be electrically powered.
Water requirements of the 400,000 bbl/day operation
could have a considerable effect on the groundwater
regime of the upper Piceance basin. Treatment and disposal
to Piceance Creek may be required to maintain pre-mine
flow rates. Groundwater levels would be lower over a larger
area (10-12 times) of the upper basin than in Case 1.
Treatment and disposal of process water would be similar.
Table 11. Estimated Dust Emissions from Various Oil Shale Surface Mining Operations-Case 2, Truck Haulage
Particulate
Rock Processed	Dust Emissions
Operations
(thousand tonnes/day)
(thousand tons/day)
(tonnes/day)
(tons''day)
Drilling
2,554*
2,810
0.28
0.31
Blasting
2,554*
2,810
0.19
021
Loading at the pit
2,554*
2,810
nil
nil
Vehicular traffic
2,554*
2,810
8.13
8.94
Primary crushing
652**
719
0.37
041
Primary screening
652**
719
nil
nil
Secondary crushing
-t
-
-
-
Secondary screening
-t
-
-
-
Conveying
-t
-
-
-
Stockpile
-t
-
-
-
Total


8.97
9~87~
*Total rock mined — overburden and oil shale.
**Oil shale only.
tRetorting process — not applicable to this study.
it

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Table 12. Estimated Dust Emissions from Various Oil Shale Surface Mining Operations - Case 2, Enclosed Conveyor
Haulage
Particulate
Rock Processed	Dust Emissions
Operation
(thousand tonnes/day)
(thousand tons/day)
(tonnes/day)
(tons/day)
Drilling
2,554*
2,810
0.28
0.31
Blasting
2,554*
2,810
0.19
0.21
Loading at the pit
2,554*
2,810
nil
nil
Conveying-Mining
2,554*
2,810
0.82
0.90
Vehicular traffic
2,554*t
2,810
0.88
0.97
Primary crushing
652**
719
0.37
0.41
Primary screening
652**
719
nil
nil
Secondary crushing
-t
-
-
-
Secondary screening
-t
-
-
-
Conveying
-t
-
-
-
Stockpile
-t
-
-
-
Total


2.54
2.80
'Total rock mined —overburden and oil shale.
"Oil shale only.
fRetorting process—not applicable to this study.
^Reduced emission factor listed in Table 6 by 85% because of no truck haulage.
although greater in magnitude, to that for the 100,000
bbl/day operation.
The disposal and reclamation of overburden, spent shale,
and residual solids for Case 2 would be similar to Case 1.
The disturbed surface exposure for the 400,000 bbl/day
operation would be about 153 hectares (378 acres). Off-site
storage would be required for 279,000,000 cubic meters
(336,000,000 cubic yards) of initial pit overburden.
Vehicular energy requirements would be 0.038 bbl of diesel
fuel per bbl shale oil for the truck haulage operation and
0.008 bbl of diesel fuel per bbl of shale oil for the conveyor
haulage operation. Approximately 1.2 kg (2.6 lbs)
ANFO/bbl shale oil would be required for blasting.
Case 3 — 1,000.000 BBL/Day Surface Mine
Case 3 is a 1,000,000 bbl/day (158,000 m3/day) surface
mine in the study area and differs in two important respects
from both Cases 1 and 2: mining equipment and strata
mined. In addition to the general assumptions made for all
case studies the specific assumptions for Case 3 are:
(1)	Enclosed conveyor/shovel mining.
(2)	All rich oil shale strata down to the R-1 stratum are
mined.*
(3)	Pit floor dimensions are 244 meters by 3,500 meters
(800 feet by 11,600 feet).
(4)	Mine life is 100 years.
Shove!/Conveyor Mining
For Case 3, the mining method selected is electric power
shovels loading both overburden and oil shale into feeder-
breakers which, in turn, load onto conveyor belts. This
method was selected principally because the scale of this
•This study does not consider processing of the leen shale zone*. It may,
however, be feasi ble to process these zones either for the shale oil only or for
the shale oil and associated minerals such as nahcolite and dawsonite. In
this study, 6-groove and zones L5-L1 are considered interburden.
mine would cause very large traffic congestion problems for
a truck/shovel operation.
Oil Shale Strata Mined
As in cases 1 and 2, overburden is mined and carried along
the mining benches and backstacked in the original
sequence. The dimensions of the mining benches are the
same as the previous cases: 30.5 meters high by 61 meters
wide (100 feet high by 200 feet wide). Overburden,
interburden, and oil shale are conveyed along the benches
to main lines. Overburden and oil shale are conveyed out of
the pit: oil shale to the retort and overburden to the
backstack area. Interburden is conveyed to a position on top
of the compacted spent shale. Spent shale is conveyed from
the retort back to the pit bottom, and is wetted and
compacted.
Table 13 lists pertinent mining statistics for Case 3. The
average stripping ratio is 1.35 tonnes of overburden per
tonne of oil shale. The improved stripping ratio is a result of
mining the deeper oil shale strata and improved resource
recovery because of a wider pit. These two factors
overcome the effect of increasing overburden thickness.
Mining Equipment Required
Table 14 lists the major conventional mining equipment
estimated to be required for Case 3.
Support equipment would add an estimated 30,300
liters/hour (8,000 gallons/hour) of fuel consumption.
Approximately 273,000 tonnes/year (300,000 tons/year)
of ANFO are required for blasting.
Reclamation
Other than scale, the major reclamation difference
between Case 3 and the previous cases is that compacted
and wetted spent shale is placed directly on the pit floor,
and interburden which is primarily lean oil shale is stacked
above the spent shale. Overburden is placed on top of the
interburden. All transportation is provided by conveyors
and compaction is done by dozers.
12

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Table 13. Mining Statistics - Case 3, Mature Pit
Overburden - thousand tonnes/day (thousand tons/day)	1,715	(1,886)
Interburden - thousand tonnes/day (thousand tons/day)	740	(814)
Total Spoil - thousand tonnes/day (thousand tons/day)	2,455	(2,700)
Oil Shale - thousand tonnes/day (thousand tons/day)	1,822	(2,004)
Oil Shale - average grade, liters/tonne (gallons/ton)	87.4	(21.0)
Shale Oil - thousand bbl/day (thousand m3/day)	1,000	(158)
Stripping Ratio - tonnes spoil/tonne oil shale	1.35:1
Mining Advance - meters/year (feet/year)	189	(620)
Surface Disturbance - hectares/year (acres/year)	120	(297)
Table 14. Case 3, Major Mining Equipment
Type
Size
Number
Required
Power
D-diesel
fuel
E-electric
Diesel Fuel
Consumed
(liters/hr)
(gallons/hr)
Shovels
Bulldozers
Rock
Drills
Conveyors/
Feederbreakers
23 cubic meters
(30 cubic yards)
3x10s joules/
second
(740 horsepower)
25 centimeters
(9.75 inches)
80
800
32
45,400
n/a
n/a
n/a
12,010
Initial pit overburden and interburden, which must be
permanently or temporarily stored is 2,388,000,000 cubic
meters (3,129,000,000 cu yds) - a very large amount.
Water Management
Open pit operations for the 1 million bbl/day production
requires mining to depths of 725 meters (2,400 feet). Water
requirements for Case 3are 331,000 liters/minute (87,500
gallons/minute) based on 3 bbls water/bbl shale oil.
Because of the pit depth, aquifer systems above and below
the Mahogany zone will be impacted and demetered to
some extent.
Dust
Table 15 lists estimated dust emissions from the Case 3
mine based on the same methodology used for the Case 2
conveyor operation. The vehicular emission factor (Table 6)
has been reduced by 85% to account for the absence of
truck haulage, and a conveying-mining function has been
added because of the substitution of conveying for truck
haulage.
The elimination of truck haulage, the major contribution to
dust emissions, could reduce the estimated levels of dust
for Case 3 to slightly more than twice the level of Case 1,
although the shale oil production of Case 3 is ten times that
of Case 1 and the total rock mined is five times that of Case
1.
Summary-Case 3 Environmental Impacts
Estimates of dust emissions for Case 3are 4.53 tonnes/day
(4.98 tons/day). Fuel consumption by mining equipment is
estimated to be 1.82 x 106 liters (480,000 gallons) of diesel
fuel/day. Based on emission data (Table 8), this would
result in the following emission rates per day:
SOa	11.2 tonnes/day (12.3 tons/day)
NOz	24.6 tonnes/day (27.1 tons/day)
Aldehydes	2.4 tonnes/day (2.6 tons/day)
and Ketones
Total	44.8 tonnes/day (49.3 tons/day)
hydrocarbons
Total	26.9 tonnes/day (29.6 tons/day)
particulates
The 1,000,000 bbl/day open pit operation would have
major impacts on the water resources in the upper basin.
The stratified pre-mining local geology would be replaced
by a more-or-less homogeneous medium after backfilling.
The interface between the upper and lower, more saline,
aquifer would thereby be removed. Also, without
substantial pretreatment and maintenance of flow to
Piceance Creek, the quantity and quality of surface water in
the lower basin would be reduced. Many of the potential
impacts on the hydrology of the basin couid be irreversible,
but with proper design and control, many of these impacts
can be kept to a minimum.
13

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Table 15. Estimated Dust Emissions from Various Oil Shale Surface Mining Operations - Case 3
Particulate
Rock Processed	Dust Emission
Operation
{thousand tonnes/day)
(thousand tons/day)
Itonnes/day)
(tons/day)
Drilling
4,277*
4,704
0.47
0,52
Blasting
4,277*
4,704
0.32
0.35
Loading at the pit
4.277*
4,704
0.01
0.01
Vehicular traffic
4,277*J
4,704
1.37
1.51
Primary crushing
1,822**
2,004
1.48
1.63
Primary screening
1,822**
2,004
nil
nil
Secondary crushing
-t
-
-
-
Secondary screening
-t
-
-
-
Conveying
-t
-
-
-
Stockpile
-t
-
-
-
Total


4.67
5.14
*Total rock mined—overburden and oil shale.
**Oil shale only.
tRetorting process—not applicable to this study.
^Reduced emission factor listed in Table 6 by 85% because of no truck haulage.
Surface environmental impacts of the 1,000,000 bbJ/day
operation might not be as significant as other impacts.
Spent shale and residual solids would be buried at the pit
floor. Reclamation activities would limit disturbed surface
exposu re to 120 hectares (296 acres); less than that for the
400,000 bbl/day operation due to the deeper pit. Storage
requirements for initial pit interburden and overburden
would be substantial, 2,388,000,000 cubic meters (10
square miles to a depth of 300 feet).
A substantial relocation of zoologic species could occur
directly from mining and from the large inffux of mine and
support personnel. Vehicular energy requirements would
be 0.011 bbl diesel fuel/bbl shale oil. Electric powered
conveyors would be the major energy consumers in
production. Since these would not be conventional
equipment, quantified energy requirements are not
available. Approximately 0.8 kg (1.7lb)ANF0per bbl shale
oil would be required for blasting.
Section 4
Summary
Analysis of the projected impacts of surface mining at the
levels of 100,000 bbl/day, 400,000 bbl/day, and
1,000,000 bbl/day indicates that the scale of the mining
operation plays an important role in pollutant generation
and environmental impacts. Truck and shovel mining may
be well suited for smaller operations, but truck transport
may become unmanageable in Cases 2 and 3. Reclamation
activities also present some unanswered questions based
on the scale of the projected mines and amounts of
materials to be moved, stored, and replaced.
Water-related impacts appear to be minimal for the Case 1
mine with only some local dewatering taking place. At the
Case 2 and 3 levels, water requirements tor mining,
retorting, and spent shale disposal exceed projected mine
dewatering rates. In this situation, additional damage may
result in area or basin-wide groundwater depletion and
aquifer mixing.
Particulate emissions are generated primarily by haul-road
traffic and diesel engine exhaust. Using conveyers instead
of trucks for Case 2 yields a reduction of approximately 7
tons/day of dust emissions and 30 tons/day of diesel
engine particulates. The most promising areas for
improvement in levels of particulate emissions appear to be
in reducing truck traffic and in improving the emission
characteristics of diesel engines.
Economies of scale, both with respect to output and final pit
depth are not apparent. In view of the relatively favorable
environmental i mpacts associated with smaller operations,
detailed economic evaluations of mine size should be
performed to determine the appropriate scale of operations.
References
1.	Weeks, John B., George H. Leavesley, Frank A.
Welder, and George Saulinier, Jr., "Simulated
Effects of Oil Shale Development on the Hydrology of
Piceance Basin, Colorado," Geological Survey
Professionaf Paper 908, 1974.
2.	"Technical and Cost Evaluation of Candidate Large-
Scale Open Pit Oil Shale Mining Methods in
Colorado," Suntech, Inc., for U.S. Bureau of Mines,
Contract No. 50241046, July 1976.
3.	Miller, Glen A., telephone communication to Arnold
H. Pelofsky, June 23, 1981.
4.	Office of Technology Assessment, An Assessment of
Oil Shale Technologies, Washington, DC, June
1980.
5.	Heistand, R.N., and W.G. Holtz, "Retorted Shale
Research," 13th Oil Shale Symposium Proceedings,
Colorado School of Mines, 1980.
6.	Harbert, H.P., and W.A. Berg, Vegetative
Stabilization of Spent Oil Shale, EPA-600/7-78
021, 1978.
7.	Nevers, T.D., et a!., Predicted Cost of Environmental
Controls for a Commercial Oi! Shale Industry, Vol. 1,
14

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D.R.I., University of Denver, Report C00-5107-1,
prepared for U.S. Department of Energy, July 1979.
8.	Crawford, K. W., et al„ Preliminary Assessment of the
Environmental Impacts from 0/7 Shale
Developments,!able 3-11, EPA-600/7-77-069, July
1977.
9.	Bates, Edward R., and Terry L. Thoem, Editors,
Environmental Perspective on the Emerging Oil
Shale Industry, Table 3-1, EPA-600/2-80-205a,
1980.
10.	Chalekode, P.K., T.R. Blackwood, and S.R. Archer,
Source Assessment: Crushed Limestone, State of
the Art, Table 1, EPA-600/2-78-004e, April 1978.
11.	Stern, A.C. et af. Fundamentals of Air Pollution,
Academic Press, 1973.

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