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April 8,2016 C-1981-025/North Thompson Creek Mine CCW <br /> soil. The amount of water that makes it to the Refuse Pond is often minimal. The design of the pond is to <br /> impound excess water from Pond P-9. The Refuse Pond would only discharge if the level of the water reaches the <br /> spillway. Minrec will only allow the water to fill the pond until there is two feet of freeboard left. If Pond P-9 and <br /> the Refuse Pond reach capacity,the water discharging from Pond T-2 can be switched to discharge out of Outfall <br /> 001. Outfall 001 is the approved NPDES discharge point for the site. Discharge out of Pond T-2 has been routed <br /> to Pond P-9 since May of 2010. Detailed maps of the passive water treatment system can be seen on Map D-2-5 <br /> and Map D-3-2 of the C-1981-025 North Thompson Creek Mines DRMS Permit. <br /> -Discharge from Mine No. 3 is first piped from the reclaimed portal to a manhole located on the north side of <br /> North Thompson Creek Road. From there the Mine No. 3 discharge is piped down to the long pond, located on <br /> the north side of North Thompson Creek near Mine No. 1. The manhole at Mine No. 3 has a primary discharge <br /> pipe,which flows to the Long Pond, and a secondary discharge pipe which flows under North Thompson Creek <br /> Road and daylights on the hill below the south side of the road. The purpose of the secondary discharge pipe is to <br /> prevent the mine discharge from building up behind the Mine No. 3 portal in the event the primary discharge pipe <br /> becomes blocked. The secondary discharge pipe used to be permitted as Outfall 007. Iron laden water began to <br /> flow from Mine No. 3 after a wet spring in 1995. The Discharge from Mine No. 3 was switched to the Long Pond <br /> on August 1 Ith, 1995. Outfall 007 is no longer used as the primary discharge point for Mine No. 3. <br /> -The cause of the discharge through the secondary pipe at Mine No. 3 was determined to be a partial blockage of <br /> the primary discharge pipe approximately 150 to 200 feet away from the manhole. Stanley Muhr had arrived at <br /> the mine site earlier in the morning,prior to the inspection. By the start of the inspection, Stanley Muhr had <br /> located the section of the pipe with the partial blockage and had begun to flush the pipe out. After the blockage in <br /> the pipe had been flushed the water level in the manhole began to fall. Discharge from the secondary pipe soon <br /> after stopped completely(Photo 1). The Iron staining on the hillside was a combination of old deposits and new <br /> deposition due to the recent flow. The extent of the iron staining ran from the end of the secondary pipe,down the <br /> hill approximately 100 feet to where the hillside leveled out(Photos 2, 3, and 4). The water stopped <br /> approximately 50 to 75 feet before North Thompson Creek and seeped into the soil. No water from this event <br /> directly discharged into North Thompson Creek. The orange staining seen on the hillside is due to the oxidation of <br /> the iron in the water from Mine No. 3. <br /> - Continued inspection of the mine site after the partial blockage was cleared confirmed the passive treatment <br /> system was functioning as designed. Mine No. 1 and Mine No. 3 were discharging into the Long Pond(Photo 5). <br /> The Mine No. 1 pipe was flowing at about 5 to 10 gallons per minute and the Mine No. 3 pipe was discharging at <br /> approximately 2 to 4 gallons per minute. The Water from the Mine No.3 pipe was orange in color due to the <br /> recent activity of flushing out the pipe. The Mine No. 3 water discharging into the manhole was not the same <br /> color as the Mine No. 3 water discharging into the Long Pond. The water entering the manhole was clear, similar <br /> to the water seen discharging into the Long Pond during the DRMS inspection on 3/29/2016, about a week earlier. <br /> At the time of the inspection the water entering the Long Pond discharge pipe was visibly clear(Photo 6). The <br /> embankments of the Long Pond are well vegetated and stable. Treatment pond T-1 was impounding water and <br /> discharging clear water into the open channel to Pond T-2 (Photo 7). The embankments of T-1 are stable and have <br /> no indications of erosion. Pond T-2 was impounding water and discharging through the primary spillway. The <br /> embankments of T-2 are well vegetated and there are no indications of instability. The water leaving the T-2 <br /> Number of Partial Inspection this Fiscal Year: 1 <br /> Number of Complete Inspections this Fiscal Year: 3 <br /> Page 3 of 9 <br />