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2006 AHR McClane & Munger Canyon Mines Page 3 <br />As discussed in previous reports, the area in the mine that experienced an inflow of <br />water was sealed in 1990. In July of 1992 all areas to the north of the East Mains were <br />sealed and are now inaccessible. Figure 3, McClane Mine Map shows the location of <br />the seals; as well as, the area of the mine that is not accessible. The sealed area is <br />lower in elevation than accessible areas of the mine but is undoubtedly still <br />experiencing an inflow of water. The volume of the portion of the mine behind the seals <br />is equivalent to about 124 million gallons. At the rate of inflow being experienced in <br />1990, 3.9 gallons per minute, it would take about 60 years for the sealed area to fill with <br />water. <br />Source of Water Inflow <br />As detailed in previous reports, the water flowing into the mine seems to be a mix of <br />water infiltrating the graben along the faults and water in the coal seam. The zone of <br />saturation of the coal seam was initially estimated using the results of exploration <br />drilling. The drilling indicated that holes in the McClane graben were dry; specifically, <br />holes 7-15-3 and 7-21-1. <br />Additionally, a piezometer installed down dip from the mine outside of the graben has <br />not realized water to date. Since the piezometer is down-dip and is dry it is apparent <br />water flowing into the mine is from a perched aquifer in the area of the coal mine. <br />• The water within the perched aquifer flowing into the mine probably comes from surface <br />water infiltration along the faults east and west of the mine. Both faults have ephemeral <br />drainages crossing their surface trace. These faults may be one source of recharge to <br />the perched aquifer. The water then infiltrates the coal seam which has become <br />saturated over time. This assumption is supported by the previously documented <br />cyclical nature of water inflow corresponding with periods of precipitation <br />Future Water Inflow <br />All future mine development is in the saturated zone so mine inflows/seeps should be <br />relatively continuous with the inflow slowly increasing. <br />As shown on Figure 4.2-3, the saturated strata appear to outcrop in the valley formed <br />by the north split of Munger Canyon. Since the strata in the area dip at four percent to <br />the northeast water may be infiltrating the seam along the valley bottom. Any water <br />infiltrating the strata at this location will flow down dip until the aquifer is totally saturated <br />unless there is an area where water may escape. The elevation of the saturated zone <br />would approximate the elevation of the outcrop (5,600 ft) if no water flows out of the <br />strata at a lower elevation. There are no known springs or seeps that would allow <br />escape of the water from the zone of saturation so it can be expected the coal seam will <br />be saturated near the outcrop elevation. <br />I• <br />