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3.1.4 Pre-Mining Potentiometric Surface <br /> Simon Hydro-Search has used observations from 1959 and 1961 to estimate the equilibrium static <br /> water level beneath the Sunnyside Basin. Mr. Bob Ward (mine superintendent during <br /> construction of the American Tunnel) personally saw that the static water level in the <br /> Washington Inclined Shaft was approximately 50 feet below F level during the summer of 1959. <br /> Mr. Ward's recollection appears reasonable in light of a letter from D. Hutchinson to Messrs. <br /> William R. McCormick and Robert M. Hurst dated February 3, 1961. This letter states that <br /> during January of 1961 (after the American Tunnel had intersected some of the fractures under <br /> the old workings) "the water was 97 feet below F level and falling 31/2 feet per day". The <br /> observed water levels in 1959 and 1961 were below F level where drainage to the surface would <br /> have occurred via the Terry Tunnel. The 1959 static water level reflects a lack of dewatering <br /> during the preceding 20-year period during which time the mine was inactive. The 1959 static <br /> water level is thought to represent an equilibrium condition of inflow to the workings versus <br /> outflow via natural fracture permeability. It is worth noting that this static water level is deep <br /> enough that most of the minor joints would be sealed by the overburden pressure (see Section <br /> 3.1.2). <br /> Direct surface-water inflow to the mine in 1959 was far less than today. Hence, the static water <br /> level in 1959, estimated at 11,500 feet above mean sea level (msl), is assumed to approximate <br /> the static water level in the fractured bedrock prior to commencing mining. <br /> sanjuan\sunny\110361\oet91 Rpt 18 <br /> 8�� s i m o n Hr,, [an a n, Emnn c H <br />