United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-86/022 Aug. 1986
&ER& Project Summary
Literature Survey of
Environmental Concerns
Associated with In Situ
Coal/Oil Shale Operations
D. D. Fischer
In situ goal gasification and in situ oil
shale retorting exhibit a number of
unique areas of environmental concern.
Available data are summarized to as-
sess the potential impacts on four
areas: (1) groundwater due to leaching
of residual materials left underground,
(2) those due to subsidence, (3) air qual-
ity due to percolation of gases up
through the overburden with subse-
quent release to atmosphere, and
(4) those due to co-produced solid
wastes consisting of particulate matter
coated with condensed hydrocarbons.
Impacts on groundwater are the great-
est environmental concern; subsidence
is of somewhat less, but still significant,
concern.
This Project Summary was devel-
oped by EPA's Air and Energy Engineer-
ing Research Laboratory, Research Tri-
angle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report or-
dering information at back).
Introduction
Development of in situ technologies
for the recovery of coal and oil shale has
been underway in the United States
since the early 1970s and later 1960s,
respectively. Because in situ processing
is designed to eliminate or, in the case
of modified in situ oil shale retorting,
greatly reduce the mining operations
normally associated with conventional
fossil fuel recovery operations, a num-
ber of unique environmental concerns
are associated with these in situ proc-
esses. All are directly related to the in
situ processing of the respective re-
sources. This task was commissioned
with the objective of collecting and eval-
uating existing information on these en-
vironmental areas of concern associ-
ated with underground coal gasification
and in situ oil shale retorting.
Conclusions
Specific findings for each technology
are presented in the full report. The fol-
lowing summarizes potential environ-
mental problems found during the
course of the study.
Impacts on Groundwater
In situ processing results in the for-
mation of pyrolysis products and ash
materials that remain underground. As
groundwater flows into these areas,
leaching of these materials occurs and
contamination of the groundwater re-
sults. Depending on the degree of con-
tamination, treatment of this ground-
water may be required to prevent
transport of contaminants away from
the area.
Subsidence
In situ processing involves the re-
moval of large quantities of material.
The void volume created may be of suf-
ficient size to cause subsequent failure
of the overburden material above the
area where processing is conducted,
leading to deformation of the ground
surface with both vertical and horizontal
components of displacement. Subsi-
dence may also enhance the potential
for groundwater contamination.
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Post-Operational Gas Leakage
At termination of in situ operations,
the void volume created underground is
filled with gases at pressure. Depending
on the geologic conditions and subsi-
dence potential, there may be a poten-
tial for these gases to percolate through
the overburden material to the surface,
with subsequent leakage to the atmos-
phere.
Co-Produced Solid Wastes
The raw gases escaping to the surface
during in situ processing contain vary-
ing amounts of paniculate matter. This
paniculate matter is removed from the
gases and is coated with condensed or-
ganic materials which are also con-
tained in the raw product gases. Dis-
posal of this material may require
special handling depending on its prop-
erties.
Recommendations
Substantial deficiencies are apparent
in the data base for both technologies.
Pre-operational baseline groundwater
quality data were not gathered at either
underground coal gasification site. Field
data for groundwater at in situ oil shale
retorting sites are essentially non-
existent. In the latter case, the qualifier
must be added that sites where testing
has occurred were dry or nearly so,
making monitoring either impossible or
extremely long-term. Where possible,
future operations should include suffi-
cient pre-operational groundwater
monitoring, so that more meaningful
results can be obtained.
Documentation of quality assurance/
quality control procedures utilized to
ensure analytical data validity and a de-
tailed historical description of ground-
water sampling/preservation/anafyses
procedures also would enhance the
ability to assess the data. Availability of
raw data would also be helpful.
In the area of subsidence, the major
deficiency is the lack of a predictive
model. Major efforts have been under-
way to overcome this, but the complex-
ity of the problem does not promise
near-term succes. Until such a model is
available, assessment of the potential
for the occurence of subsidence will re-
main more qualitative than quantitative.
D. D. Fischer is with Radian Corporation, Austin, TX 78766.
Robert C. Lagemann is the EPA Project Officer (see below).
The complete report, entitled "Literature Survey of Environmental Concerns
Associated with In Situ Coal/Oil Shale Operations," (Order No, PB 86-209
780/AS; Cost: $11.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S7-86/022
PS
CHICAGO
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