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<br /> <br /> <br /> <br /> 19 <br />Prior to the middle of 1995, the mine water discharge at Mine No. 3 was from a <br />point source inflow (spring) within the mine. This spring discharge, consistently <br />less than 10 gallons per minute, was of good quality and, from 1986 to mid-1995, <br />was slightly alkaline with no history of iron or sediment problems. It was piped to <br />the surface and discharged directly to North Thompson Creek at a former CDPS <br />discharge point 007. Groundwater inflows began to fill Mine No. 3 after cessation <br />of mining and pumping. Flooded mine waters nearly discharged in 1993 (rose to <br />near-portal elevation), but then resided. From 1991 through 1993, iron (total) <br />concentrations in the spring flow were below 0.02 mg/1. Concentrations of iron <br />in the spring discharge rose from values around 0.02 mg/1 on April 30, 1994, to <br />0.055 mg/1 on May 16, 1995, and a significant increase in discharge flow rate and <br />concentrations of some parameters was noted on June 26, 1995. Mine water <br />elevation measurements indicated that the No. 3 Mine had flooded to the portal <br />elevation. The discharge (combined spring and mine overflow) jumped to 67.5 <br />gallons per minute. Iron concentrations rose significantly from 0.055 mg/1 on <br />May 16, 1995 to 6.21 mg/1 on Jun 26, 1995. TSS rose from <10 to 55 mg/1, and <br />TDS from 845 to 1150 mg/l. By July 25, 1995, flow had dropped to 34.7 gallons <br />per minute, TSS fell to 35 mg/1, but TDS rose to 1235 mg/1 and total iron to 6.82. <br />These values exceeded CDPS standards established for Mine No. 1 discharge. <br />Outfall 007 discharge was conveyed to the water treatment systems established at <br />Mine No. 1 for treatment effective August 11, 1995. Except for one known date <br />(inspection of April 26, 2001), there has been Mine No. 3 discharge reported in <br />periodic inspections since the 1995 event. By dilution, combined untreated <br />discharges from Mine No. 3 and Mine No. 1 were in compliance with the prior <br />approved CDPS permit parameter limits (measuring 0.03ppm on December 5, <br />2005, the last sample taken prior to the termination of the CDPS Permit). <br /> <br />On or around April 20, 2006, The CDPHE Water Quality Control Division <br />(WQCD) terminated the Colorado Discharge Permit No. C0-0029599. WQCD <br />subsequently wrote a letter to Minrec, Inc. stating that the CDPS permit should <br />not have been terminated and requested that Minrec, Inc. submit an application for <br />a new CDPS permit. The reason WQCD requested a new permit at the North <br />Thompson Creek Mine is because of the passive water treatment system treating <br />the No. 1 and No. 3 Mine Portal discharges. WQCD requires a discharge permit <br />on all water treatment systems. The issue of concern is that the discharge from the <br />No. 3 Mine Portal has an iron concentration that exceeds the receiving stream <br />standard. However, after the No. 1 Mine and the No. 3 Mine discharges mix and <br />flow through the passive treatment system, the majority of the iron is removed and <br />the resulting discharge is in compliance with receiving stream standards. The new <br />permit, CO-048233, was issued on February 1, 2010. <br /> <br />After the passive treatment system, the water flows through the NPDES discharge <br />point. This is the point where the water quality is measured. North Thompson- <br />Four Mile Mineral and Land Corporation (NTFM) has been active in diverting the <br />treated water from this point away from North Thompson Creek back on to their <br />property into storage ponds for private use.