United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S7-81-024 May 1981
Project Summary
Characterization of Two
Core Holes from the Naval
Oil Shale Reserve Number 1
R. D. Giauque, J. P. fox, and J. W. Smith
This study was conducted by Lawrence
Berkeley Laboratory for the Industrial
Environmental Research Laboratory -
Cincinnati, U.S. Environmental Pro-
tection Agency, and for the Laramie
Energy Technology Center of the U.S.
Department of Energy. Two hundred
eighty (280) raw oil shale samples
from two core holes on the Naval Oil
Shale Reserve Number 1, located in
the Piceance Basin of Western Colorado,
were analyzed to determine the strati-
graphic variability of major, minor,
and trace elements and to determine
their association with major minerals.
This Project Summary was developed
byEPA'slERL, Cincinnati to announce
key findings of the research project
that is fully documented in a separate
report of the same title (see Project
Report ordering information at back).
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Cincinnati. OH.
to announce key findings of the re-
search project that is fully documented
in a separate report of the same title
(see Project Report ordering informa-
tion at back).
Introduction
Green River oil shale is a marlstone
that contains about 20 percent organic
material. It was deposited from an
ancient lake that covered parts of
Colorado, Utah and Wyoming. This lake
was probably permanently stratified.
The upper portion supported life, and
the lower layer was probably a sodium
carbonate solution with a pH of 11 to 12.
Oil shale was formed by lithification of
sediments accumulated at the bottom of
this lake. These materials entered the
lake by overland runoff and atmospheric
fallout of dust, pollen, and volcanic ash.
Vertical variability in major, minor,
and trace elements and mineral phases
in oil shale deposits have been previously
noted. This variability is significant from
an environmental, economic and process-
ing standpoint. Vertical modified in-situ
(VMIS) retorts will span 300 to 700 feet
or more of a vertical section of oil shale.
Large changes in elemental and mineral
concentrations through these sections
may produce oils, gases and waters of
varying compositions. These variations
may affect treatment of the waters and
gases and upgrading of the oil. Signifi-
cant changes in mineral forms and
elemental composition across a VMIS
retort will also affect the process energy
balance and any catalytic effects due to
specific elements. Similarly, in surface
retorting, richer deposits are mined and
retorted in surface retorts. If environ-
mentally undesirable elements are con-
centrated in some horizons and not in
others, it may be feasible to eliminate or
minimize some environmental problems
by preferentially mining the deposits.
Both environmentalists andgeochem-
ists are interested in the magnitude and
significance of stratigraphic variations.
To the geochemist, stratigraphic distri-
bution is a variable answering questions
about depositional trends. To the en-
vironmentalist, stratigraphic distribution
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provides information on the size and
significance of the overall consequences
of developing that oil shale deposit and
controls that might be used to prevent
adverse environmental impacts. Environ-
mental concerns center around poten-
tially hazardous elements such as Hg,
Cd, and Se.
This report provides some of this basic
information. It discusses the stratigraphic
distribution of elements, minerals and
Fischer Assay oil and water content in
two cores from the Colorado Naval Oil
Shale Reserve No. 1, the site of much
developmental testing and the source of
most of the Green River Formation oil
shale samples discussed in U.S. oil
shale literature.
Method
The detailed measurements were
made on 280 samples from core holes
15/16 and 25 and are presented in the
report. A computerized data system was
used to plot histograms.
For statistical purposes, the results
determined for each core hole were
broken down into individual groups. The
groups corresponded to the different
stratigraphic zones for which samples
were composited at 5-foot (1.5 meter)
intervals or less. The overlying oil shale,
the upper Mahogany Zone, the Mahogany
Bed, the lower Mahogany Zone and the
rich oil shale were the five stratigraphic
zones of core hole 15/16, for which the
above criterion was met. The corre-
sponding stratigraphic zones of core
hole 25 were composited at intervals
similar to those of core hole 15/16,
except there was not a rich oil shale
zone.
Relative minimum-maximum values
were calculated for each variable on a
group basis for each core hole. Pearson
correlation coefficients and correspond-
ing statistical significance values were
determined for pairs of variables for
each of the above groups.
The report lists the range of Fischer
Assay and mineral results for both core
holes, and summarizes concentration
ranges for all the elements. In nearly all
cases, the range of values for each
variable is very similar for the two core
'holes. This illustrates, in a broad manner,
the degree of horizontal uniformity
across the Green River oil shaledeposit.
The report summarizes relative mini-
mum-maximum values determined for
each variable by stratigraphic zone and
presents them as bar graphs. The report
presents histograms of results for indi-
vidual composite samples from the two
core holes.
Pearson correlation coefficients and
corresponding statistical significance
values were calculated for each variable
pair on a group basis.
Statistical significance values were
determined for 48 individual elements
paired with 29 of the same elements.
Statistical significance values were also
calculated for 48 individual elements
paired with eight minerals and Fischer
Assay products oil and water.
Results
The most notable result of this study
was the demonstration of a remarkable
stratigraphic uniformity in mineral and
element composition of oil shale from
both cores. This uniformity is apparent
in the histograms and in the average
elemental concentrations summarized
by stratigraphic zone. The resulting
averages and their associated standard
deviations demonstrate the uniformity
under discussion. However, some ele-
mental averages do not show uniformity.
Fluorine and boron do not because of
their analytical uncertainties. As, Hg, K,
Sb, and Se are other elements with 99
percent error limits larger than two
times their means. They appear to fall
into two groups. As, Hg, and Se appear
to have been collected by organic matter.
K and Sb are part of a group associated
with incursion of airborne clastic influx.
Many of the elements occur in the oil
shale at levels at or below crustal
abundance. Using Mason's 1960 crustal
abundance table, only the carbonate
elements Ca, Mg, Ba, and Sr plus U, Mo,
As, Se, and perhaps Pb and W appear
enriched. The enrichment mechanisms
for the carbonate minerals depend on
their ease of precipitation. Barium ma'
be present as barite as well, but abou
half the Ba is soluble in dilute HCI. Thi
elements U and Mo appear to be associ
ated with organic matter. The As, Se
and perhaps Pb and W were probabh
initially collected by the organic mattei
and then released to form sulfides. Twc
more of the elements appear enriched, F
and B. Enrichment of these in a saline
lake is to be expected, but the certainty
of their analytical results is limited.
Conclusions
The principal phases with which the
various major, minor, and trace elements
are associated (based on statistical
analyses) are summarized in Table 1.
Specific conclusions follow.
1. Oil shale from both core holes was
comprised principally of dolomite,
quartz, analcime, calcite, Na-
feldspar, K-feldspar, and organic
matter. Mg-siderite, illite, pyrite,
and aragonite were also detected
in many of the samples. Illite was
detected more frequently in core
hole 25 (from the edge of the
depositional basin) while pyrite
and aragonite were detected more
frequently in core hole 15/16
(center of the basin). Dawsonite
and f luorite were detected in a few
samples. The concentrations of
dolomite and quartz were relatively
constant. These two minerals
typically accounted for forty weight
percent of the matrix.
2. Over one-half of the elements de-
termined correlated well with two
minerals, Na-feldspar and K-
feldspar (Table 1). Most of these
elements did not vary in concen-
Table 1. The Principal Phases with which the Various Major. Minor, and Trace
Elements are Associated
K-feldspar. Mg-siderite. Na-feldspar
Al. B. Ce, Co, Cr, Cu, Dy, Eu, Fe, Ga, Hf, La. Mn, Nd, Ni, Pb. Sb. Sc, Sm, Ta, Tb, Th. Ti, V,
Y, Yb, In, Zr
K, Rb K- feldspar, Mg-siderite
Na Na-feldspar, Analcime, Water
Cs Analcime, Water
Ba, Cmin, Ca, Sr Calcite
Mg Dolomite
As, H, Hg, Mo, N, Se, U Corg, Oil
Cd, F Unknown
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tration by more than a factor of
three or four.
3. High Fischer Assay oil yields and
elevated Na- and K-feldspar con-
centrations were concurrent in
the oil-rich Mahogany Bedfor both
core holes.
4. The composition of the two core
holes was very similar for cor-
responding stratigraphic zones
even though core holes 15/16 and
25 were from the center and the
edge of the depositional basin,
respectively, and ten kilometers
apart. These studies agree with
previous investigations that re-
vealed that oil shale is remarkably
uniform laterally.
5. Concentrations of major organic
elements—organic carbon, hydro-
gen, and nitrogen—varied by an
order of magnitude. Similar con-
centration variations were observed
for As, Cd, Hg, Mo, Se, B, and F,
which are trace elements of po-
tential environmental significance.
The first five of these elements
may be partly associated with the
organic fraction of the oil shale
matrix. Boron is associated with
the mineral phase. No definitive
conclusions could be made for F
associations based on this work.
6. The trace elements Co, Cu, Ni, Pb,
Sb, and Zn showed consistent
associations. These elements are
probably present in oil shale as
sulfides.
7. Fischer Assay water yield was
strongly associated with analcime
content in both cores. However,
the water in analcime typically
accounted for only about one-third
of the water content determined
by Fischer Assay.
P. D. Giauque, J. P. Fox, andj. W. Smithare with the Lawrence Berkeley Labora-
tory. Berkeley, CA 94720.
Edward R. Bates is the EPA Project Officer (see below).
The complete report, entitled "Characterization of Two Core Holes from the
Naval Oil Shale Reserve Number 1," (Order No. PB 81-167 736; Cost: $ 15.50,
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
U.S. QOVERNMENT PRINTING OFFICE. 1««1 -757-012/7113
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