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ft/day, respectively, for these two pa remote ra. Although no aquifer characteristics for • <br />the Wolf Creek Coel could be found in the literature, S[ewart (1983) gives a <br />transmissivity of 0.4 ft2/day and a hydraulic conductivity of 0.007 ft/day for the Wolf <br />Creek coal end underburden. In this instance, the Wolf Creek tool unit at Yoast appears <br />to be slightly more transmissive/conductive then in surrounding areas. <br />Trout Creek Sandstone Aquifer. While mining at Yoast during the first five-year permit <br />term will not directly affect units stratigraph ically lower than the Yadge underburden, <br />Seneca does anticipate drilling one production well into the Trout Creek sandstone <br />aquifer. This will be drilled in Section 8 along the north access road (see Exhibit 73-2, <br />Tab 13). She Trout Creek sandstone does not outcrop on or near the lease area, but it is <br />the principal local source of water suitable for domestic use. Published transmissivities <br />for this unit range from 0.5. to 2800 ft2/day while hydraulic conductivities range from <br />4.4x10E-06 to 9.0 ft/day (Table 7-11). A single pumping test was conducted at the Seneca <br />11-V production well, which is completed in the Trout Creek sandstone. The results of <br />this test provided a transmissivity of 23.3 ft2/day end a hydraulic conductivity of <br />1x10E-O1 ft/day. <br />As indicated by the information presented above, aquifer characteristics measured in wells • <br />on the Yoast leasehold are generally et the low end of the range of values determined for <br />the region. Aquifer yields in the~Wadge overburden and underburden may be relatively low <br />due to low secondary porosity. Brogden and Giles (1977) report that well yields are <br />higher in the Twentymile Perk area where fracturing is extensive. However, Robson and <br />Stewart (1990, P. 64) report that the effect of fracturing on hydraulic conductivities in <br />the Twentymile sandstone is relatively insignificant since pe rmeebilities measured in the <br />field (vie aquifer tests) end in the laboratory (of unfractured samples) were not <br />statistically different. Comparison of in-situ versus laboratory-derived hydraulic <br />conductivities for the Trout Creek sandstone, however, show chat fracturing may play a <br />greeter role in providing for higher local well yields from this formation (refer to Table <br />7-77). <br />Robson and Stewart (1990, P. 54-64) view the thin sandstone end coal aquifers of the lower <br />member of the Williams Fork Formation es a single hydrologic unit, collectively referred <br />to as the ~~besel Yilliems Fork aquifer". This local "aquifer" includes ell of the <br />stratigraphic units above the Trout Creek sandstone (uppermost member of the Iles • <br />Formation), end below the middle shale member of the Williams Fork Formation. This <br />assemblage would encompass the Wolf Creek coal end underburden, Wedge overburden, coal, <br />36 <br />