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January 10, 2003 <br />Page 4 of 4 Pages <br />was determined not to be a viable alternative to seepage control (permit, page 4-66g). Flow from the <br />#3 Mine was anticipated and is described on page 4-115b of the permit. At this time, gravity <br />dischazges are evident at the Mine 1 and Mine 3 portals. Portal discharges, from both the Mine 1 and <br />Mine 3 aze collected and treated. <br />"Water discharged will comply with the applicable CDPS permit." (Permit, page 4-126) The report <br />validates this statement for 2002 discharges. <br />A statement that discharges from outfall 001 may slightly impact the quality of water in north <br />Thompson Creek, and a hypothetical case, is described on page 4-122 of the permit. An increase of <br />less than 10% in conductivity is considered insignificant (a dischazge of 52 gpm, conductivity of <br />2083, stream flow of 5 cfs). A statement on page 4-122 of the PAP, and page 5 of the report, is that <br />the Depaztment of Health can consider a loading of one ton of salt per day a no-salt discharge. An <br />expected maximum flow rate of 100 gpm from the No. 1 mine, with a TDS concentration of 1500 <br />mg/1 would yield a salt concentration of 0.9 tons per day. The average flow for 2002 was 22.4 <br />gallons per minute (gpm) with a TDS concentration of 1388 mg/1. This equates to a discharge of <br />0.191 tons of salt per day (page 6 of the report). <br />Samples for potentially dissolved iron of the individual, and collective, mine portal dischazges were <br />taken on September 8, 2002. The untreated No. 1 Mine discharge was measured at 0.08 mg/1. The <br />untreated No. 3 Mine discharge was measured at 1.29 mg/1. The combined discharge was measured <br />at 0.30 mg/1. The CDPS limit is 0.43 mg/1. <br />CC: Dan Hernandez, CDMG <br />C:\ W PDOCS\NorthThompson\ahrrvw02.025.doc <br />