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INTEROFFICE COMMUNICATION <br />Date: September 4, 2002 <br />To: Bob Oswald <br />From: Harry Posey <br />Re: Midas Mine, Ophir Lode Water Quality Results, M-2001-063 <br />I looked over the analyses from 4 sampling stations at the Midas Mining Co. Ophir lode, headwaters of <br />Henson Creek. <br />Nothing too remarkable was noted; neutral pH drainage with very slightly elevated Zn (typical) and mostly <br />non-compliant Mn values (fairly typical of headwaters streams in high organic, i.e. potentially reducing <br />streams). <br />Site #4 and #6 each had slightly non-compliant AI contents. This is somewhat unusual and could occur <br />either because samples were not filtered correctly and thus the analyses reflect sediments of clay or <br />feldspar in the sample. Otherwise, an AMD source may be present upstream causing AI-bearing mineral <br />dissolution which then grows diluted by the time it reached these points. <br />Documenting these elevated numbers will be important for potential future actions. Given the oddly <br />elevated AI values and the chance for AMD sources upstream, I would strongly recommend that the <br />operator collect waters during spring flush next year. If AMD is present upstream, this would be the most <br />likely time for it to appear in water quality analyses. <br />