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3.3 Pie-Mining Potentiometiic Surface <br />Simon Hydro-Search has used observations from 1959 and 1961 to estimate the <br />equilibrium static water level beneath the Sunnyside Basin, Mr. Bob Ward (mine <br />superintendent during construction of the American Tunnel) personally saw that the <br />static water level in the Washington Inclined Shaft was approximately 50 feet below <br />F level during the summer of 1959. Mr. Ward's recollection appears reasonable in <br />~~ light of a letter from D. Hutchinson to Messrs. William R. McCormick and Robert M. <br />Hurst dated February 3, 1961. This letter states that during January of 1961 Salter <br />the American Tunnel had intersected some of the fractures under the old workings) <br />"the water was 97 feet below F level and falling 3'/~ feet per day". The observed <br />water levels in 1959 and 1961 were below F level where drainage to the surface <br />would have occurred via the Terry Tunnel. The 1959 static water level reflects a lack <br />of dewatering during the preceding 20-year period during which time the mine was <br />inactive. The 1959 static water level is thought to represent an equilibrium condition <br />of inflow to the workings versus outflow via natural fracture permeability. It is worth <br />noting that this static water level is deep enough that most of the minor joints would <br />be closed by the overburden pressure. <br />Direct surface-water inflow to the mine in 1959 was far less than in 1992. Hence, <br />the static water level in 1959, estimated at 11,500 feet above mean sea level (msl), <br />is assumed to approximate the static water level in the fractured bedrock prior to <br />commencing mining. <br />sunnylwpltraci122511Mar1993.Rpt 1 <br />HHI SIi11011 HYDRO-SEARCH <br />