2009-08-25_PERMIT FILE - C1991078A

• Permit No: C1991078A
• IBM Index Class Name: Permit File
• Doc Date: 8/25/2009
• Section_Exhibit Name: 2.04 Environmental Resources
• Media Type: D
• Archive: Yes

. 2.04.6(2)
Geochemical Analysis
(b) The cores from two exploratory holes were analyzed
for geochemical parameters to identify physical and chemical
properties of the overburden, interburden and the stratum immedi-
ately below the lowest coal seam to be mined and the extent of any
materials which may have an adverse effect on the environment. The
two exploratory holes used were CC-1-90 and CC-3-90 both of which
are within the proposed permit area.
No significant ground water is expected to discharge
though the spoil piles or through the regraded surface. The
potentiometric surface of the ground water in the area is some 100
feet below the lowest coal seam to be mined and impermeable layers
of shale totaling about 20-feet thick, exist between L-he lowest
coal seam to be mined and the aquifer. See section 2.04.7 for a
further description of this aquifer.
The main concern with the physical and chemical
properties of the overburden/interburden is whether any material
exists that will adversely effect reclamation. Following is an
interpretive summary to compare the analytical results obtained
from the samples with established guidelines so potential problems
with reclamation can be identified. Results are compared with the
suggested guidelines of the Wyoming Department of Environmental
Quality ,(DEQ), guideline No. 1 dated November 1984 or the Montana,
Department of State Lands Guidelines, (DSL).
~H The pH values of the eleven samples ranged
from 3.6 to 7.6 with an average of 6.2. The DEQ sets a suitable pH
range for overburden and regraded spoil from 5.5-8.5 with a
marginal range of 5.0-9.0. Two of the samples had pH values of
less that 5.0. Both were in the CC-1-90 core hole immediately
above and below the lowest coal seam to be mined. The sample
immediately below the lowest coal seam will not be disturbed so it
is not a concern regarding vegetation. The pH value for the sample
immediately above the coal seam was 4.4. It is probable that the
overburden removal process will mix this low pH material with the
overburden material above which has a pH of 7.4 and the resulting
blend will result in a suitable pH for overburden and regraded
spoils. The reclamation plan will provide for a monitoring plan to
delineate any unsuitable areas of regraded overburden with respect
to pH. The results of the monitoring plan are presented in Exhibit
7 beginning on page 7-32.
From a visual observation of the core material and specifi-
cally the material that exhibits a low pH, it is evident that
pyritic sulfur is the cause of the low pH.
C J
2.04-8 September 1994