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• 2002 AHR McClane & Munger Canyon Mines Page 2 <br />sampling locations that was derived from Figure 4.2-2 of the McClane Canyon Mine <br />permit. <br />Mine Water Inflow/Discharge <br />Water was discharged from the mine beginning in May 2002. Flows into the mine are <br />estimated in table 1. Previous hydrologic reports have shown the inflow of water to the <br />mine can be attributed to dewatering of a perched aquifer as well as surface water <br />infiltration along the faults of the graben. During the mid 1980's, a clear picture of mine <br />water inflows was obtained because water collected in the faces was regularly pumped <br />to outfall 002 and discharged. The quantity of water discharged was recorded on a <br />meter and correlated with precipitation. The steady decrease in the amount of water <br />pumped from the mine during the idle years is evidence of the creation of a dewatered <br />zone in the saturated coal strata. This decrease also provides evidence there is little <br />communication with the comparatively large aquifer within the East Salt Creek alluvium <br />across the west fault of the graben. <br />When mining resumed, additional area in the saturated portion of the graben was <br />exposed, increasing the flow of water into the mine. The inflow of water went from a <br />low of 0.80 gpm in 1988 to a high of 3.87 gpm. in 1990. Water flowing down dip into <br />the faces was pumped to the sump and used in the mining process for dust control. On <br />• April 27, 1990, Section 001 was abandoned and sealed. <br />A small amount of water was trucked to the mine for supply road dust suppression <br />starting in October 1999 prior to production. When production resumed in February <br />2000 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 with <br />production demands, a sump was established and the section was moved to the south. <br />The water in the East faces is pumped to the sump and again used in the mining <br />process for dust control thus reducing the amount of water trucked to the mine. The <br />inflow of water into the mine is estimated to be approximately 10.5 gpm based on the <br />mine's demand for water and the amount of water discharged and consumed for dust <br />suppression. Table I gives a month by month total of the water trucked to McClane <br />Canyon, Table 6 gives quality results of mine inflow/seep sampling. <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 />