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Source of Water Inflow <br />As detailed in previous reports, the water flowing into the mine <br />seems to be a mix of water infiltrating the graben along the faults <br />and water in the coal seam. The zone of saturation of the coal seam <br />was initially estimated using the results of exploration drilling. <br />The drilling indicated that holes in the McClave graben were dry; <br />specifically, holes 7-15-3 and 7-21-1. Additionally, a piezometer <br />installed downdip from the mine outside of the graben has not <br />realized water to date. Since the well is down-dip and is dry it is <br />surmised that the water flowing into the mine is from a perched <br />aquifer in the area of the coal mine. <br />The water within the perched aquifer flowing into the mine probably <br />comes from surface water infiltration along the faults east and west <br />of the mine. Both faults have ephemeral drainages crossing their <br />surface trace near the mine and may receive water from the <br />drainages. The water then infiltrates the coal seam which has <br />become saturated over time. This assumption is supported by the <br />previously documented cyclical nature of water inflow corresponding <br />with periods of precipitation. <br />MUNGSR CANYON MINE <br />To date there has been no water encountered by this mine; therefore, <br />there has been no effect on the hydrologic regime of the area. A <br />current mine workings map is included as Figure 2. Table 1 <br />documents that a small amount of water was used to erect temporary <br />seals in the mine portals. Although the mine has been sold to GVC, <br />the seals will remain in place as an added measure of protection <br />against unauthorized entry. <br />PRECIPITATION <br />Based upon Bureau of Land Management records from a rain gage in <br />Ashford Canyon, the 1992 water year was a near "normal" year. Total <br />precipitation of 18.06 inches was 94 percent of average recorded <br />there during the last eleven years. Table 2 shows the daily <br />precipitation record. Table 3 contains monthly totals for the <br />Ashford Canyon site since 1977. About half of the rainfall this <br />year, 43 percent, occurred during the months of October, March and <br />May. The records for the Ashford Canyon rain gage do not give a <br />precise record of the precipitation at the mines. Typically, <br />thunderstorms are localized and may only effect one of the many <br />canyons in the area. A large storm this summer is a good example of <br />this pattern. <br />On Sunday night July 12, 1992 a storm deposited about 2.5 inches of <br />rain. According to people living near the mine, the storm lasted <br />for about one half hour. The storm seemed centered on McClave <br />Canyon and the north split of Munger Creek east of the mine. Almost <br />no water was in the sediment traps at Munger. A mile north of the <br />mine the ditches were dry. <br />Page - 3 1/29/93 <br />