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pressure. <br />The mines located on the south side of the North Fork of the <br />Gunnison River are within the discharging areas of the aquifers. <br />The mines located on the north side of the valley are within the <br />recharge areas of the aquifers. <br />' 2.2 Future Mine Development <br />2.2.1 Mine Plan Through 1989 <br />' The Orchard Valley mine will be expanding form the existing <br />mine toward the north-east between 1985 and 1989. The proposed <br />mining methods and hydrogeologic conditions in the area to be <br />mined by 1989 are quite similar to the conditions in the existing <br />mine. Geologic and hydrogeologic characteristics of the area to <br />be mined by 1989 were investigated by exploration boreholes and <br />the results are presented in Volume 2, Geology and Mine Planning <br />of the application for permit to mine. Therefore, no substantial <br />differences in the characteristics, quantity or quality, of the <br />water inflow into the mine are anticipated. No significant <br />drainages will be undermined during this period and the mine will <br />generally be expanding deeper and, therefore, the overburden <br />thickness will be increasing. <br />In this case, where no significant aquifers or surface <br />sources of water are present, the most applicable method of mine <br />' water inflow calculation is the method of Hydrogeologic Analogy <br />(Ramenskij, et. al, 1957). This method is based on a comparison <br />of water inflow into an existing mine, (as related to mined area <br />or volume) to a potential of water inf low into a newly projected <br />' mine. A condition for the successfull application of this method <br />is the similarity of hydrogeologic characteristics between the <br />existing mine and the new mine or section of a mine. <br />' A specific inflow, q, in the existing mine per acre of mine <br />opening was calculated from the equation: <br />1 q = 4/A <br />where: q = specific inflow into the mine <br />(gpm/acre) <br />Q = total inflow into the existing <br />mine (gpm) <br />A = area of mine openings (acres). <br />Specific inflow into the Orchard Valley mine at the end of <br />1984 was calculated as q = 0.0061 gpm/acre. Using the specific <br />inflow for the existing mine and the Hydrogeologic Analogy for <br />the five year mining plan, the following mine inflow rates were <br />established: <br />4 111 UHU.1; Y: U r a l\51' LT \.~TS <br />