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-39- <br />In -Situ Permeability of Mine Bock: The in -situ permeabilities <br />measured in the walls of the mine with the packer tests are presented <br />in the following table: <br />Location <br />IN -SITU MINE ROCK PERMEABILITY <br />Coefficient of Material <br />Permeability Description <br />(cm. /sec.) <br />1 No water take Sandstone, hard, massive <br />2 No water take Sandstone, soft, friable <br />3 2 x 10 -4 Fault breccia <br />4 4 x 10 -3 Sandstone, fractured, <br />friable, thin lenses of <br />claystone and siltstone <br />5 2 x 10 -5 Sandstone, hard, thin <br />bedded, lenses of soft, <br />friable sandstone <br />6 7 x 10 -5 Sandstone, hard, <br />thick <br />bedded, thin claystone <br />beds. <br />In our opinion, the permeability tests conducted in the mine rock <br />indicate that the majority of the material has a low permeability. <br />The results of Test 4 are the single exception to this general <br />conclusion, and these tests represent the results in the fractured, <br />friable sandstone material which is encountered in a very small <br />fraction of the surface area in the mine drifts. Where localized <br />7acturing is encountered in the mine, mine -guard is applied to <br />'port the mine drift. Shotcrete is a relatively impermeable <br />trial which reduces the permeability of the fractured in -situ mine <br />rock. <br />