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Mine Water Inflow / Discharee No water has been discharged from the mine and no flow into the mine has been noted this year. Previous hydrologic reports have shown that the inflow of water to the mine can be attributed to dewatering of a perched aquifer as well as surface water infiltration along the faults of the graben During the mid 1980's, a cleaz picture of mine water inflows was obtained because water that collected in the faces was regularly pumped to NPDES point 002 and discharged. The quantity of water discharged was recorded on a meter and a correlation with precipitation was made. The steady decrease in the amount of water pumped from the mine during the idle years is evidence of the creation of a dewatered zone in the saturated coal strata. The decrease is also evidence that there is little communication with the comparatively large aquifer within the East Salt Creek alluvium across the west fault of the graben. When mining resumed, additional azea in the saturated portion of the graben was opened, increasing the flow of water into the mine. The inflow of water went from a low of 0.80 gpm in 1988 to a high of 3.87 gpm in 1990. Water flowing downdip into the faces was pumped to the sump and used. On Apri127, 1990, Section OOl was abandoned and sealed. Since then, all water necessary for operations has been trucked to the mine. Table 1 gives a month by month total of the water trucked to McClave Canyon. Since no production occurred in 1995, no water was imported for use at the mine. Approximately 7,000 gallons of potable water was trucked to the site for the mine o$ces. As discussed in previous reports, the area in the mine that created water was sealed in 1990 and no water has been produced in other areas of the mine since then In July of 1992 all areas to the north of the East Mains were sealed and aze now inaccessible. Figure 1, McClave Mine Map, shows the location of the seals; as well as, the area of the mine that is not accessible. These areas are lower in elevation than active areas are undoubtedly still experiencing an inflow of water. The volume of the sealed workings is now about 124 million gallons. At the rate of inflow being experienced in 1990, 3.9 gallons per minute, it would take about 60 years for the sealed area to fill with water. Only then will the mine realize a detectable inflow of water from the areas that had been making water previously. It is possible that water will be encountered as the mine extends farther to the east and then north as shown in Figure 2.1.1 of the permit application Additional water may be infiltrating the seam in the valley formed by the north split of Munger Canyon If water is once again encountered, its existence will be documented and detailed in future reports. Source of Water Inflow As detailed in previous reports, the water flowing into the mine seems to be a mix of water irtSltrating the graben along the faults and water in the coal seam The zone of saturation of the coal seam was initially estimated using the results of exploration drilling. The drilling indicated that holes in the McClane graben were dry; specifically, holes 7-15-3 and 7-21-1. Additionally, a piezometer installed downdip from the mine outside of the graben has not realized water to date. Since the piezometer is down-dip and is dry it is apparent that the water flowing into the mine is from a perched aquifer in the azea of the coal mine. The water within the perched aquifer flowing into the mine probably comes from surface water infiltration along the faults east and west of the mine. Both faults have ephemeral drainages crossing their surface trace neaz the mine and may receive water from the drainages. The water then infiltrates the coal seam which has become saturated over time. This assumption is supported by the previously documented cyclical nature of water inflow corresponding with periods of precipitation. AHI2 - 95 Page - 2 1 - 26 - 96