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Thompson Creek treats the dischazge from this mine. No record of laboratory sampling of <br />the dischazge from the pond has been recovered during this review. Mine No. 2 water was <br />once reported as acid and toxic (a field measurement of a 2.5 pH by Division staff). Field <br />measurements of May 20, 2003 (Division staff) of dischazge from the treatment pond of <br />pH was 8.2 and of TDS was 1780 mg/1. Flow was measured as 1.09 gallons/minute. <br />Only two springs, Spring 1 and Spring 2, aze identified in the PAP. <br />A tributary from the southwest discharges into North Thompson Creek between the <br />upstream and downstream monitoring stations. <br />Alluvial groundwater may flow into North Thompson Creek. In addition, there was no <br />monitoring of a bed-rock seep below Mine No. 1. See the discussion of ground water for <br />these potential contributions. - <br />(d) Receiving Stream Standazds <br />Monitoring suggests that, at times, some parameters in North Thompson Creek maybe <br />above receiving stream standards, but except for sulfate, not a result of Outfa11001 <br />dischazges. Baseline and monitoring water quality data aze available in the permit <br />documentation from, for various times, at a location upstream and a location downstream <br />of pemutted mining activities, Mine No. 1 and Mine No. 2 inflows (during mining), Mine <br />No. 1 and Mine No. 2 untreated dischazges, Spring SP-1 and Spring SP-2, and Outfall <br />001. There is no information on water quality of the seep just below Mine No. 1. It has a <br />strong sulfur smell, and leaves a crust of precipitate in the vicinity of the seep. <br />Baseline flows of North Thompson Creek, as recorded by the United States Geological <br />Service at a gage station just above the mine permit azea, ranged from a high May 1964 <br />flow of 322 cubic feet per second (cfs) to a low September 1964 flow of 0.3 cfs. <br />Discharges from Outfall 001 have ranged from 160 gallons per minute (gpm) to 15.3 gpm <br />(0.36 - 0.034 cfs) during 1996 through 2002. September Outfa11001 flows have ranged <br />from 61.1 gpm in 1997 to 21.8 gpm in 2002 (0.049 cfs). The September 2002 Outfa11001 <br />discharge of 0.049 cfs would be 14 percent of downstream North Thompson flow at the <br />0.3 cfs baseline. Flows from springs, seeps, and from Mine No. 2, aze low (one gallon per <br />minute or less each), but indicate that certain constituents are introduced into North <br />Thompson Creek from other than Outfa11001 dischazges. <br />In general, the increases between upstream and downstream North Thompson Creek <br />receiving stream standazds pazameters are greatest during low flows. The effects of <br />Outfa11001, and dischazges from other sources, on North Thompson Creek are expected <br />to be greatest during low-flow conditions of North Thompson Creek, and September data, <br />when available, is evaluated as such in this renewal fmdings. In this review, Table Value <br />Standazds of Numeric Standazds were calculated based on a water hazdness of 174.69, as <br />detemvned from a calcium concentration of 46.6 mg/I and a magnesium concentration of <br />22 <br />