2013-10-07_REVISION - C1981025 (8)

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Disturbed surface areas from mining operations have been reclaimed. The operator demonstrated in Bond Release SL-04 that contributions of suspended solids from these reclaimed areas are not greater that contributions from adjacent undisturbed areas. There has been no recorded overland surface flow from reclaimed disturbed areas of the permit to North Thompson Creek. All former sediment control structures have been reclaimed, or permitted for retention for other purposes. The determination was made in Bond Releases SL- 4, SL-5 and SL-6 that there is no adverse impact to surface waters by surface runoff from the mine site. (b) Flows from Mine Portals Seepage was noted in the vicinity of the No. 1 Mine portals on April 28, 1988. This water was determined to require treatment (a pH of 6.8, suspended solids of 2,180 mg/1, and recoverable iron at 120.6 mg/1). Collection systems were installed, and discharge was treated by a drip hydroxide system to lower the pH and precipitate the iron, with detention. The drip system was determined to be unnecessary; detention without chemical treatment was sufficient. This flow now comes from the No. 1 Mine airshaft and is conveyed to the current passive treatment system. The current treatment system consists of collection and transmission pipes, and a series of ponds (Long Pond, Treatment Pond 1, Treatment Pond 2, and the option for additional treatment in Pond P-9). There is no mixing of surface runoff from disturbed areas with these mine water discharges. Water from the mine water treatment ponds bypasses sediment ponds and is discharged to North Thompson Creek at CDPS Outfall 001. The locations of the portal areas, the mine water collection system, and treatment ponds are shown on Drawing D-3-2 of the PAP. Analyses on September 8 and October 12, 2002 of the untreated discharge from the No. 1 Mine indicated that the untreated discharge met water quality parameters of the CDPS permit requirements without treatment in the detention ponds. However, the discharge continues to pass through the detention ponds and discharge at Outfall 001. Prior to the middle of 1995, the mine water discharge at Mine No. 3 was from a point source inflow (spring) within the mine. This spring discharge, consistently less than 10 gallons per minute, was of good quality and, from 1986 to mid 1995, was slightly alkaline with no history of iron or sediment problems. It was piped to the surface and discharged directly to North Thompson Creek at a former CDPS discharge point 007. Groundwater inflows began to fill Mine No. 3 after cessation of mining and pumping. Flooded mine waters nearly discharged in 1993 (rose to near-portal elevation), but then resided. From 1991 through1993, iron (total) concentrations in the spring flow were below 0.02 mg/1. Concentrations of iron in the spring discharge rose from values around 0.02 mg/1 on April 30, 1994, to 0.055 mg/1 on May 16, 1995, and a significant increase in discharge flow rate and concentrations of some parameters was noted on June 26, 1995. Mine water elevation measurements indicated that the No. 3 Mine had flooded to the portal 17