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Foidel Creek Mine Geology. A lithologic log of the hole is presented in Exhibit <br />' 14, Lithology Logs. The hole was drilled into the strata 12 feet below the <br />Wadge seam. Core samples were collected from the roof material 5 feet above the <br />coal seam, from the coal seam itself, and from the floor material 5 feet below <br />' the coal seam. The core samples were delivered to the lab for leachate testing. <br />' In addition to the core samples, aggregate samples of actual waste rock <br />material were collected from the underground mine. The aggregate samples came <br />' from roof material entering the mine from roof falls, fault crossings, or <br />overcast mining operations. The aggregate samples were also delivered to the <br />' lab for leachate testing. <br /> Hydrologic Conditions <br />' The proposed disposal site is in Area 2 Pit, located adjacent to the Foidel <br /> Creek Mine portal area at the Energy No. 1 Mine. The Area 2 Pit is an open <br /> excavation with a bedrock highwall on the north side and a spoil slope on the <br /> south side. The bedrock on the highwall side contains a sequence of saturated <br />' sandstone and siltstone units referred to as the "overburden aquifer". The <br />characteristics of the overburden aquifer are fully described in Section 2.04.7 <br />' of Twentymile Coal Company Permit No. C-056-82. <br />' The permeability and storativity <br />ti <br />d <br />t <br />i <br />d b <br />d <br />t <br />t <br />t of the overburden aquifer have been <br />mit <br />r <br />At <br />l l <br />ti <br />i <br />th <br /> e <br />erm <br />ne <br />y con <br />uc <br />ng pump <br />es <br />s a severa <br />oca <br />ons <br />n e per <br />a <br />ea. <br /> the Energy No. 1 Mine, average horizontal permeability is 2.9 gallons per day <br />' per square foot, vertical permeablity is 0.1 gpd/f t2, and storativity is 1.7 x <br /> 10-4 (unitless). The average yield of wells penetrating t he overburden aquifer <br />' is 17.6 gpm. Hydraulic conductivities in the overburden aquifer are therefore <br /> very low, except in localized areas where the aquifer has been extensively <br />' fractured by joints and faults. <br />' The spoil material up-dip from the pit forms an unconfined aquifer which <br /> serves to recharge the local ground water system. Water from snowmelt and <br /> rainfall infiltrates into the spoils, and flows down-dip along the pit floor <br />' where it pools up against the highwall. At times of the year when the head of <br /> <br />2 <br /> <br />