2007-11-01_PERMIT FILE - C1982056A

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Based on the most recent groundwater inflow studies (2006), anticipated mine inflows are estimated at approximately 55 gpm for the SMD and WMD, 65 gpm for the EMD, 95 gpm for the NMD and SMN/6MN Shafts, and 10 gpm for the North Mains and Portal azea. Additional system inputs include approximately 4 gpm from the • potable water well, and approximately 163.6 acre-ft for operational use annually from Pond A. Total annual water use is approximately 533.3 acre-ft annually, although the majority of the water is recycled. Mine Water Balance: System inputs and outputs for the mine can be estimated to determine a mine water balance. Historically (1983 through August 1998) two different mine water balance conditions have existed: 1) When water has been stored in the sump at the northwest comer of the SMD and 2) When all water that entered the mine has been pumped out. From the beginning of mining to July 1996, the mine was kept dewatered except for the sealed 1~' South Panels. From July 1998 to August 1998, the northwest comer of the SMD was allowed to flood, with groundwater inflow to the SMD and other water pumped into the SMD from the NMS and the EMD. Since August 1998, sealed workings in the southern portion of the EMD have been established as a temporary water storage area. Some pumping of and discharge from [he SMD and EMD sumps has occurred to maintain the water level in the flooded workings below the seals. Wish installation of the new tongwall in 2006 and the new washplant in 2007, mine water use increased to the point where discharge was no longer necessary to maintain stable water levels. Therefore, a simplified mine water balance, developed in early 2007, reflects the practical reality that any difference between system inputs and outputs results in a corresponding increase or decrease in mine water storage levels. The water balance consists of the following primary components: System Inputs • Groundwater inflow to the mine workings • Water contributions from the potable water well • Operational use from Pond A Svstem Outputs • Surface moisture shipped with the coal product • Mine ventilation losses • Washdown water discharged through the sedimentation ponds (or lost to evaporation) • Evaporative losses from the surfaces of all mine impoundments Svstem Balance • Mine water discharge (previous historical practice) • Changes (positive or negative) in the volume of water stored in sealed mine workings The water balance for water years 1993 to 2002 is presented in Exhibit 51, Table E51-3. The original water balance was calculated shortly after longwall mining started. The inflows to the NMS were estimated to be constant at 45 gpm, based upon past mine inflow studies. For years 1989 to 1993 inflows to the SMD were calculated based on the total of the other inflows minus the outflows. In 1994, the pool at the Fish Creek borehole began to expand. For water years 1994 to 2002, the excess inflow was assigned to the sump and the SMD, inflow was estimated to be 55 gpm, based on mine inflow surveys at the time. Inflows to the EMD were estimated from the areas mined and the actual inflow measured. Itt 1995, approximately 200 acres were affected by longwall mining, yielding an estimated 5 gpm. Some fault inflows were encountered at the end of the water yeaz. In 1996, approximately 800 acres in the EMD were affected by mining, yielding approximately 20 gpm, including the fault inflows. In 1997, excluding the inflows from 6-Right, a total of approximately 1,400 acres were affected, yielding 35 gpm plus 10 gpm from the Southeast Sub-Mains. In 1998, excluding the inflows from 6-Right, a total of approximately 2,000 acres were affected, yielding an estimated 55 • gpm plus ] 0 gpm from the Southeast Sub-Mains, which are located in the EMD. All dust control water from the active longwall and continuous miner equipment, plus all inflows to the EMD, excluding the 6-Right inflow, are collected in a sump at 10-Right. The sump maintained a constant pool level by pumping at approximately 170 gpm since 1998. The estimated inflows to this azea are 65 gpm from groundwater, and 111 gpm from the equipment, for TR07-59 2.05-137 04/02/07