2022-09-29_PERMIT FILE - C1980007 (2)

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West Elk Mrne Table 57 TDS Concentrations and Loads Relative to 2001 CHIA Anal sis Scenario Avg. Continuous Discharge Rate ( pm) TDS Concentration (mg/L) Annual Salt Loading (tons/ ear) Percent of CHIA Loading 1996 270 2 000 1 180 4% 2002 284 1,887 1,922 6% "Worst Case° 500 3 000 3 290 11 2001 CHIA 5,520 2,500 30,159 --- Water Oualitv Implications oI Discharge to Lone Pine Gulch MCC currently discharges mine water form the Sylvester Gulch mine dewatering facility. The Lone Pine Gulch portals were sealed and reclaimed in 2002 and 2003. Water Ouality Impacts oI Sylvester Gulch Pumping Plant Operational As of August 2000, the risk to North Fork water quality posed by the mine decreased because: The pumping facility in Sylvester Gulch became operational The maximum dischazge capacity of this facility is 2,000 gpm. 2. Having removed the stored water in the sealed sumps, MCC has capacity to store neazly 800 acre-feet of water within the NW and NE Panels sealed sumps. 3. The sealed sumps provide effective treatment (i.e. reduction of TSS) of the mine water prior to pumping out of the sumps. North Fork Impacts Irom Sumped Groundwater Flows As presented in the Groundwater Quantity Effects section of this permit, if the sumps aze ultimately used by MCC to their full capacity, a maximum calculated "worst case" groundwater outflow to the North Fork of approximately 0.7 to 8.4 gpm is calculated to occur (based on available B Seam permeability data), but MCC's actual experiences defines this rate to be closer to zero. Filtration, adsorption, absorption, and other factors will act on constituents in the water as it moves downgradient. MCC's actual experience when drilling the in-mine horizontal drill hole into the NW Panels sealed sump from entries developed from the northwest corner of the 11NE longwall panel, confirms that the mine water outflow from the sealed sumps will likely be less than the calculated worst case outflow, as above. The total length of the drill hole (called NW Sump #1 horizontal drill hole) was approximately 232 feet and no water was encountered during drilling of this hole through the B Seam until the hole was only 17 feet from the sealed sump -even with an estimated 65 feet of water head at this location for nearly a year. At a seepage rate of only 0.7 to 8.4 gpm, North Fork water quality will not be measurably affected by groundwater outflows from the sumps. 2.05-239 Revised Jwe 2005 PRIG; Rev. March 2006; Rev. May 2006 PRI G