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West Elk Mine Wells GP-3, GP-4, GP-6, and GP-7 were subsequently completed on the east-side of the Lower Refuse Pile. Falling head permeability tests were performed on these wells in order to estimate the permeability of the colluvial soils in this azea. Field permeability values were determined to be between 2.1 and 3.9 x 10~ centimeters per second (2 to 4 feet per yeaz). Permeability tests were also performed on two shallow boreholes (10 and 15 feet deep) at the initial waste rock pile to determine the permeability of the upper portion of the colluvial soils. The falling head tests indicated a permeability of approximately 1.0 to 1.2 x 10~ cm/sec (1.0 to 1.2 feet per yeaz). Alluvium The alluvium of the North Fork consists of mixed sand, cobbles, and boulders capped by finer sands and silts. In the vicinity of West Elk Mine, the North Fork alluvium is relatively narrow and ranges from 40 to 70 feet in thickness. Alluvial deposits within the coal lease area are generally less than 25 feet thick and are part of the active groundwater regime. Where sufficient saturated thickness can be found, alluvial deposits may yield more abundant groundwater. Well AL-1, completed in the alluvium of the North Fork, has a reported sustained production rate of 17.4 gpm as determined from pumping tests. The resulting transmissivity was estimated to be less than 500 gpd/ft (Table 5). A pumping test conducted by Bear Coal Company on an alluvial well neaz the site of Beaz No. 3 Mine yielded a transmissivity of 806.5 gpd/ft. Pumping tests conducted by Colorado Westmoreland, former operator of the Orchard Valley Mine, indicate that the alluvial ~_ deposits of the North Fork tributary of Stevens Gulch were of sufficient thickness to support a pumping rate of about 28 gpm. Transmissivity values and well (SG-1) yields within the alluvium of Sylvester Gulch, another tributary to the North Fork, indicate a sustained production of about 1 gpm and an extremely low transmissivity of about 120 gpd/ft (Table 5). In the South of Divide permit revision area, the Dry Fork of Minnesota Creek represents the most significant alluvial deposit. Three wells, A-1 (AV-1), A-2 (AV-2), and A-3 (AV-3), were completed in the alluvium of Dry Fork of Minnesota Creek in August of 1984 (Exhibit 12). Of the three wells completed in the alluvium of the Dry Fork, only well A-2 showed transmissivity results characteristic of an alluvial aquifer and consistent with results from tests on wells on the North Fork or its tributaries. These wells were monitored for a period of time after the installation, but aze not part of the current groundwater monitoring program. Two new alluvial/weathered bedrock wells (Upper Dry Fork and Lower Dry Fork) were constructed in 2003 to obtain additional information on this hydrostratigraphic unit. These wells showed the alluvium to be approximately 25 to 30 Feet thick with a saturated interval of approximately 20 feet. Monitoring of these wells was initiated in fall 2003 and will be ongoing to provide baseline and operational water level data for the South of Divide area. E Seam mining in the South of Divide permit revision azea will occur approximately 1,200 feet below the alluvial materials associated with the Dry Fork of Minnesota Creek. As previously stated, the alluvial materials aze part of the surface and neaz-surface active groundwater regime in the Dry Fork drainage and thus in direct hydraulic communication with seasonal and climatic events. This is in contrast to the E Seam groundwater, which is part of the inactive groundwater 1.04 -70 Revised November 1004 PRI G