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(c)(i) Mine inflows will not be impounded above the normal ground level at the lowest <br />portal. In the Roadside South Mine, water was allowed to fill abandoned areas <br />below an elevation of approximately 4762 feet; the ground elevation of the <br />Northwest Intake portal. A siphon was installed in this portal seal to allow <br />discharge through outfall 002 of the CDPS permit. <br />During March of 2000 a 4-inch diameter pipe was installed from the No. 2 South <br />Mains Sump to outfall 001. The pipe penetrates the South Portal seal as shown <br />on Figure 14-2. The pipe intercepts water that flows to the Northwest Intake <br />Pool and therefore increases the overall mine discharge capability. <br />The siphon and 4-inch dewatering pipe was a reliable mine dewatering system. <br />However, a high level of monitoring and some periodic maintenance was <br />required. Therefore, the Operator identified a location where a angled hole could <br />be drilled into the mine and water would flow by gravity form the mine (see figure <br />14-10). <br />r1 <br />LJ <br />During 2001 the operator drilled the angled hole into the Roadside South Mine. <br />The hole was completed with and 8-inch diameter pipe during March 2002. The <br />North Decline dewatering system was put into service during April 2002 with <br />discharge through outfall 016 of the CDPS discharge permit. Outfall 016 has <br />proved to be a reliable mine dewatering point. Since April 2002, flow from the <br />mine has averaged about 220 gpm with a maximum flow of 280 gpm. <br />The North Decline gravity dewatering system is the primary dewatering system <br />for the mine. The siphon and South Portal dewatering pipe are backup systems. <br />The Roadside North Mine is entirely below the portal elevation and will fill to the <br />normal groundwater level which is approximately 50 feet below the reclaimed <br />surface at the portal area. <br />I • VOL 5 Tab 17 17-6 <br />(Rev 5/03) <br />