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Cross Mine(M1977-410) Technical Revision No. 5 <br /> zr <br /> y _ <br /> • <br /> g. x <br /> . rx ^, <br /> it s,-,-- <br /> $ tF r; r " e <br /> y 4 Tia, "*.,(l',;.-'�. . t`- <br /> --r i%i <br /> , ... <br /> ., <br /> t �r7��4,. � �°�i 8,,N1'',:,411,.--f-41/4'1�( ,f �;"�tx ,k y z <br /> 5 ' - P1 cx 4 •,. ' "g,5_ .r-� ��-. '. 4 ,,„ roti at <br /> rt ' <br /> d y�-s f <br /> A <br /> i 1 <br /> f g - <br /> Photograph 3—Idaho Tunnel Portal Collapse December 19,2019 <br /> 4.3. Mine Water <br /> In accordance with the mining permit (DRMS file No. M1977 410, approved April 9, 2012), mine water <br /> was conveyed from the Idaho Tunnel by means of an 8 in diameter Schedule 40 PVC pipe and discharged <br /> into a series of sediment ponds (Figure 1). Historical monitoring indicates a typical flow range of 10 to <br /> 2,500 gallons per day during the winter, and peak of 150,000 gallons per day (104 gpm) during early <br /> summer runoff. As a result of damage in November 2019, the discharge from the pipe was reduced to <br /> less than 400 gallons per day, plus a small amount of outflow that by-passed the pipe. <br /> Untreated water from the Idaho Tunnel is directed into Stormwater Ponds #3a, b and c to allow coarse <br /> sediment to settle and then to Pond#2 where it is mixed with treated effluent from the Cross Mine portal <br /> 5 <br />