REP26668

• Permit No: C1981013
• IBM Index Class Name: Report
• Doc Name: Mine Inflow Study 1994
• Permit Index Doc Type: Mine Inflow Reports
• Media Type: D
• Archive: No

• APPENDIX C
MINE INFLOW STUDY
C-1 NEW ELK MINE
During the third quazter of 1989, the New Elk Mine was temporarily sealed and access to the
mine workings are unavailable. Any mine inflows aze flooding the abandoned mine workings.
Previous studies and reports suggested an inflow of 177 gallons per minute (gpm) into the
abandoned workings of the New Elk Mine. Calculated inflows range from 468 to 142 gpm (see
Table C-1) based on measurements taken at Station NEW-4. A number of approximations were
made in the calculation of 1944 rates of inflow. From mine maps, the dip of the mine floor was
determined to be 5%, and the water line crosses approximately 12,000 lineaz feet of mined
areas. The available volume is based on an average extraction of 60%. The calculations assume
that the entire mined area below the water level measured in NEVJ-4 is flooded (i.e., no trapped
air pockets). The appazent large inflow between August 8, 1994, and September 9, 1994, is
noted. The period of time over which measurements have been taken is too short comment on
the accuracy of the reported values. However, an early apparent trend of lowering values might
be expected. The trend could represent a lower quantity of inflows due to some recharge taking
place or reduction of inflows due to hydrostatic pressures at depth. Continued monitoring will
provide the information to clarify the phenomena, and permit a more accurate projection of
hydrologic consequences.
• C-2 GOLDEN EAGLE MINE
Mine inflow measurements were taken annually in August to determine the quantity of water
flowing into the Golden Eagle Mine. Location of inflow measurements are indicated on
Figure C-1 (Figure 1, Golden Eagle Inflow Map, Rev. 5, 2/03/95). Areas which were
examined included all active and inactive underground mine workings. Point source inflows
were found at faults, fractured roof, fractured floor, exploration drill hole, etc. Area wide
inflows were observed as drainage from seals to abandoned mine workings; azeas of weeping
coal faces, roof, or floors; and unsealed mine areas; etc. Table C-2 presents the location,
probable water source, and estimated gpm for each of these sources. Major sources were
measured volumetrically while seepage and weeping faces were estimated.
In 1992, a total inflow of 181.3 gpm, equivalent to 292` acre-feet was estimated. Flow
associated with the fault in SE-1 was approximately 80 gpm (this fault system was encountered
during early 1988). Air shafts, the slope and drill holes (sources 2, 6, 7, 8, 9, 12, I4, 28}
accounted for 12.1 gpm and the remainder was from seepage originating in the coal seam.
Table C-3 presents temperature, conductivity and pH measurements of some of the inflows.
. ` (181 gpm) x (60 m/h) x (24 h/d) x (365 d/y) _ (7.4805 g/ft') _ (43,560 ft/a) =acre feet/year
HYDRPC94.292\9\d1-28-952:13pm) C-1