Laserfiche WebLink
Dave Berry and Susan McCannon, CDMG <br />February 18, 1998 <br />Page 2 <br />Mine had experienced an increase in mine inflows prior to November 1 I, 1996, when MCC <br />began storing large volumes of water in the NW Panels. <br />5. While mining in the 3rd West Mains, Bear personnel observed a wet face along the south wall, <br />but inflows were not sufficient to measure. There were no observed fractures that would allow <br />direct communication of water from MCC's NW Panels to the Beaz No. 3 Mine. These <br />observations are consistent with those of MCC personnel, who observed no significant faults <br />or fractures along the north end of the NW longwall panels opposite this location. Neither <br />MCC's nor Bear's observations support the theory of secondary porosity (i.e., fractures) <br />allowing direct communication of water between the mines. In addition, weekly observations <br />at the Lone Pine Seal indicated that the water level remained relatively constant since the <br />filling of the NW Panels sealed sump. This would not be the case if 18 to 46 gpm (as reported <br />in Bear's 1995 and 1996 AHRs) were seeping downgradient. <br />6. The discharge data from 1996 as shown in Table 1 and Figure 1 indicate a definite seasonal <br />pattern with peak flows occurring during the summer. This type of trend would be expected if <br />the inflows were linked to a surface source, such as Lone Pine Gulch. Surface sources in the <br />vicinity typically have an earlier peak in the hydrograph, but this can be accounted for by <br />considering travel time through the Bear No. 3 Mine workings. However, if the source of the <br />inflows was from the NW Panels, a seasonal pattern would not be expected. <br />7. The right-hand column of Table 2 shows the cumulative water storage in the Bear No. 3 Mine <br />assuming that inflows continue at an average rate of 30 gpm, the rate reported by Bear at mine <br />closure (response #50). By November 1997, over forty acre-feet of water would have <br />accumulated in the Bear No. 3 Mine without inflows from the NW Panels sealed sump. If the <br />discharges were ceased in September 1996 following acave-in (response #13), then the <br />accumulation of water in the Bear No. 3 Mine workings without inflows from the NW Panels <br />sealed sump would have been approximately fifty acre-feet in November ]997. Thus, at the <br />time flows were first observed at the Edwards Portal spring in November 1997, there would <br />have been a significant volume of water accumulated in the Bear No. 3 Mine workings without <br />contribution from MCC's NW Panels sealed sump. <br />8. Flows from the Edwards Portal spring have been fairly constant at 20 gpm. No water has been <br />observed at any other location in the vicinity of Bear's facilities, indicating that the Edwards <br />Mine and Portal may be the preferential pathway for water migrating through the Bear No. 3 <br />Mine workings. <br />9. Observations within the West Elk Mine workings support the very low permeability of the B- <br />Seam coal calculated from slug tests. Prior to encountering the B East Mains and 14 SE <br />Headgate faults, there was no prior evidence of water until the faults were actually mined <br />through despite the water being under pressure. <br />cc: Kathy Welt, MCC <br />Phil Schmidt, MCC <br />Gene DiClaudio, MCC <br />Kirk Mueller, ARCO Coal Company <br />D:\831-032\41 Ijmk\Bear Mine Inflows.doc <br />