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2017 AHR McClane & Munger Canyon Mines Page 3 <br />alluvium across the west fault of the graben. <br />When mining resumed, additional area in the saturated portion of the graben <br />was exposed, increasing the flow of water into the mine. The inflow of water <br />went from a low of 0.80 gpm in 1988 to a high of 3.87 gpm in 1990. Water <br />flowing down dip into the faces was pumped to the sump and used in the mining <br />process for dust control. On April 27, 1990, Section 001 was abandoned and <br />sealed. <br />A small amount of water was trucked to the mine for road dust suppression starting <br />in October 1999 prior to production. When production resumed in February 2000 <br />the demand increased to approximately 373,000 gallons per month. In April 2000 <br />water started seeping from the mining faces developing to the east. To keep up <br />with production demands, a sump was established and the section was moved to <br />the south. The water from the east end of the East Mains was pumped to a sump <br />and used in the mining process for dust control. Table 1 shows the water balance <br />for water year 2016. As shown in Table 1, no water was used to water the roads, or <br />pumped to the sediment pond. Table 6 shows the quality results of mine discharge <br />sampling; however, no water was discharged during the water year. <br />As discussed in previous reports, the area in the mine that experienced an inflow <br />of water was sealed in 1990. In July of 1992 all areas to the north of the East <br />Mains within the graben were sealed and are now inaccessible. Figure 3, <br />McClane Mine Map shows the location of the seals; as well as, the area of the <br />mine that is not accessible. The sealed area is lower in elevation than accessible <br />areas of the mine but is undoubtedly still experiencing an inflow of water. The <br />volume of the portion of the mine behind the seals is equivalent to about 124 <br />million gallons. At the rate of inflow being experienced in 1990, 3.9 gallons per <br />minute, it would take about 60 years for the sealed area to fill with water. <br />Source of Water Inflow <br />As detailed in previous reports, the water flowing into the mine seems to be a <br />mix of water infiltrating the graben along the faults and water in the coal seam. <br />The zone of saturation of the coal seam was initially estimated using the results <br />of exploration drilling. The drilling indicated that holes in the McClane graben <br />were dry; specifically, holes 7-15-3 and 7-21-1. <br />Additionally, a piezometer installed down dip from the mine outside of the graben <br />has not realized water to date. Since the piezometer is down -dip and is dry it is <br />apparent water flowing into the mine is from a perched aquifer in the area of the <br />coal mine. <br />The water within the perched aquifer flowing into the mine probably comes from <br />surface water infiltration along the faults east and west of the mine. Both faults <br />have ephemeral drainages crossing their surface trace. These faults may be <br />