GENERAL33122

• Permit No: C1981033
• IBM Index Class Name: General Documents
• Doc Date: 3/31/1982
• Doc Name: PROPOSED DECISION and FINDINGS OF COMPLIANCE
• From: Mine No. 1, No. 2 & No. 3
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

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VI. Hydrologic Balance: Ground water - Rules 2.04.5, 2.04.7, 2.05.3(4),
2.05.6(3) and 4.05
For a description of the ground water hydrology of the mine area and a discussion
of the impacts of mining on ground water, please refer to the Regional Geology and
Cround Water Hydrology portion of Section IX, Probable Hydrologic Consequences and
Cumulative Impact Assessment of this document.
The ground water sections, found on pages 30-34 and 44-47-1a of the application for
the Bear No. 1 and No. 2 mines, and on pages 2.04-29 - 2.04-32, 2.05-55, and 4.05-8
through 4.05-11 of the Bear No. 3 mine application, have been reviewed by the Division
for compliance.
The following problems were identified in the P.A.R. of May ZS, 1981 and have been
fully resolved:
First, the Division noted that page 42 of the original application stated that water
was pumped from the mine to maintain the competency of floor shales for safety
reasons. The Division requested that the applicant provide data on the rate of
mine inflows and a description of the method of disposal of the water. In their
responses, the applicant explained that any water accumulation in the mine is a
result of the dust suppression system or water used with the continuous miner. The
applicant states that the Bear No. 1 and No. 2 mines have not experienced mine inflows
and that there have been no discharges. To insure the competency of floor shales,
water which accumulates in small depressions on the floor of the active mining areas
is pumped or drained to inactive areas of the mine.
Second, the Division requested additional information regarding water table extent
and storage capacity above the "F" seam (the Barren Member). The applicant provided
data collected by ARCO on the permit and adjacent area, including results of pump
tests run on wells in the Barren Member and the "F" seam, a Barren Member water
level map and water level tables.
Third, the Division requested that the applicant document the low permeability of
the Mesa Verde Sandstones, stated on~page 45 of the application. The applicant
responded that pump tests completed by RRCO, included in the application, indicate
that perrreabilities within the sandstones may vary from a fraction of one millidarcy
to as much as IO millidarcies.
There is some question as to the accuracy of the ARCO data provided at that time
regarding the aquifer characteristics of the Barren Member Sandstones. However,
the C seam is separated from the Barren Member by over 300 feet of sedimentary
strata. Only minor inflows have resulted from previous mining of the C seam in
the Bear No. 1 and No. 2. As stated in Section XXII Subsidence of this document,
the proposed mining within the Bear No. 3 is considered, by the Division, to
represent no potential threat to the Barren Member aquifers or the coal seams
overlying the C seam. The additional information requested in the P.A.R. concerning
aquifer characteristics of the Barren Member is not considered, by the Division,
to be critical to the determination of the probable hydrologic consequences of
the Bear mine.