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<br /> <br /> <br /> <br /> 18 <br />required upon renewal of the CDPS permit for copper, lead, mercury, nickel, <br />selenium and silver. Monitoring of the discharges is not required for <br />parameters that are not identified by the CDPHE as being of concern. Of the <br />water quality standards that were established for North Thompson Creek, there <br />was no testing for dissolved oxygen, fecal coliforms, F. Coli, chlorine, nitrite, <br />asbestos, antimony, beryllium, thallium, and uranium. There was no baseline <br />monitoring for silver. <br /> <br />(a) Runoff from Disturbed Areas <br /> <br />Disturbed surface areas from mining operations have been reclaimed. The <br />operator demonstrated in Bond Release No. 4 (SL-4) that contributions of <br />suspended solids from these reclaimed areas are not greater that contributions <br />from adjacent undisturbed areas. There has been no recorded overland surface <br />flow from reclaimed disturbed areas of the permit to North Thompson Creek. <br /> <br />All former sediment control structures have been reclaimed, or permitted for <br />retention for other purposes. The determination was made in Bond Releases SL- <br />4, SL-5 and SL-6 that there is no adverse impact to surface waters by surface <br />runoff from the mine site. <br /> <br />(b) Flows from Mine Portals <br /> <br />Seepage was noted in the vicinity of the No. 1 Mine portals on April 28, 1988. <br />This water was determined to require treatment (a pH of 6.8, suspended solids of <br />2,180 mg/1, and recoverable iron at 120.6 mg/1). Collection systems were <br />installed, and discharge was treated by a drip hydroxide system to lower the <br />pH and precipitate the iron, with detention. The drip system was determined to <br />be unnecessary; detention without chemical treatment was sufficient. This flow <br />now comes from the No. 1 Mine airshaft and is conveyed to the current <br />passive treatment system. The current treatment system consists of collection and <br />transmission pipes, and a series of ponds (Long Pond, Treatment Pond 1, <br />Treatment Pond 2, and the option for additional treatment in Pond P-9). There is <br />no mixing of surface runoff from disturbed areas with these mine water <br />discharges. Water from the mine water treatment ponds bypasses sediment ponds <br />and is discharged to North Thompson Creek at CDPS Outfall 001. The locations <br />of the portal areas, the mine water collection system, and treatment ponds are <br />shown on Drawing D-3-2 of the PAP. <br /> <br />Analyses on September 8 and October 12, 2002 of the untreated discharge from <br />the No. 1 Mine indicated that the untreated discharge met water quality <br />parameters of the CDPS permit requirements without treatment in the detention <br />ponds. However, the discharge continues to pass through the detention ponds and <br />discharge at Outfall 001. <br />