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in zones of greater permeability which dip southwest along the more highly fractured units. The <br /> overall effect is that the greatest permeability zones trend northeast/southwest and dip about 10° <br /> - 14' southwest. Field evidence for this anisostropy in permeability includes a preferred <br /> orientation for ore shoots. Figure 5 shows an example of a, northeast/southwest trending ore <br /> shoot which dips southwest. <br /> The fracture permeability in the vicinity of the mine is inhomogeneous. In the upper Burns <br /> Formation fracture permeability is expected to increase from Sunnyside Basin toward Cement <br /> Creek as strata become more welded (now fractured) in the direction of the original volcanic <br /> vent (see section 3.1.1). <br /> Fracture permeability generally decreases with depth as the fractures are progressively sealed <br /> by increasing overburden pressure. Evidence for this can be observed in both the American <br /> Tunnel and the Terry Tunnel. At locations deep within the mine water enters each tunnel only <br /> where major fractures are encountered, and most of the back and rib of the tunnel is dry. <br /> However, as the portals are approached decreasing overburden pressure allows relatively minor <br /> joints to transmit water and dripping water becomes common. <br /> In the deeper parts of the flow system significant quantities of water are transmitted only by <br /> major fractures. This is demonstrated by the fact that the deeper part of the present American <br /> sanjuan\sunny\11036 1\oct9 1.Rpt 13 <br /> n N simon [quan=aFnL nR <br />