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discharge. <br />Both the Roadside North and South Portals are located on rock outcrop <br />adjacent to the Colorado River. The Roadside North Portal is located north and <br />west of the river, and the Roadside South Portal is Icoated south and east of <br />the river. Mine workings at the Roadside North Portal slope away from the <br />mine portal and away from the river. Powderhorn currently pumps water out of <br />the mine in order to keep ventilation pathways open. Current (1992) discharges <br />average 110 gallons per minute (gpm) with a total dissolved solids~(ITIDS))lfof <br />approximately~700itri~'/L'~ PhisofaalrgesKotthet~.sr~rf'aee~f~ro'r~~F~ie~e,~a~e <br />°es~peo~e~o~oease^G- 6heFi"t'he rime p Ftal'°ii~ closed' N Po--(x~ m n c <br />Some of the water from the Roadside South Portal is pumped out to a surface <br />storage tank. Water from the tank is then used in the mine's processing plant. <br />Any water in excess of the needs of the plant is discharged into the river at <br />• outfall No. 001. Because the pipeline tends to freeze in the winter months, <br />most of the discharge from outfall No. 001 occurs during warm weather. On a <br />yearly basis, flows average less than 50 gpm with a TDS of approximately 1000 <br />mg/L. <br />In the past, water has been pumped from the Roadside South Portal at the <br />North Decline. The North Decline has been sealed and water is currently <br />(1993) being siphoned from the mine at the Northwest Intake (i.e. outfall No. <br />002). Long-term discharge from outfall No. 002 is expected to be <br />approximately 150 - 250 gpm, depending upon discharge from outfall 001 and <br />015, with a TDS of approximately 1500-2000 mg/I. <br />Water from the southern portions of the Roadside South Portals may be <br />pumped from the 2 West Portals and discharged to an unnamed tributary of the <br />Colorado River at outfall 015. Flow pumped through outfall 015 would reduce <br />• 19-7 (New 3/1/96) <br />