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~ • iii iiuitiiiiiu iii TRAPPER ~INIlY6 I1~C. CERTIFIED #P568141745 Ms. Sandi Marek Water Quality Control Division Colorado Dept, of Health 4210 East 11th Ave. Denver, CO 80220 Dear Sandi: Subject: Colorado Wastewater Discharge Permit CO-0032115. June 1. 1990 _~ r-- n ,- :1 -., r, ' ~~ _ ~. - UPI t. i`3~'., ._.~~ ~ :J 'yi :Vv ~,,.' ~~'t I n4~t f`~.ri. As reported to you by telephone on May 31, 1990, Trapper Mine measured a pH value of 9.2 at NPDES point 001 (Johnson Gulch) during routine surface water sampling on 5/30N0. The 9.2 pH value exceeded our current (WQCD administrative extension of expired permit) effluent limitation to discharge under the Colorado Discharge Permit System. As in the past, the elevated pH reading is a result of low water flows combined with warm temperatures causing significant algae growth to develop in the sediment ponds. To eliminate further discharge from this location, the discharge siphon associated with the principle spillway will be temporarily blocked. If water begins to flow through the principle spillway a carbon dioxide bubbler will be installed. As mentioned in our hone conversation, the pH in No-Name (site 002) is also elevated although it does not exceed our effluent Itmitation of 9.0. The rtse in pH of No-Name waters is also related to extensive algae growth within the pond. As suggested, Trapper will conduct additional pH monitoring at both 001 and 002 NPDES sites (early morning, mid-afternoon and any inlet Oow of water into these sites) to confirm algae is the culprit in pH exceedances at these locations. Sandi, we will continue with our present course of treatment unless instructed by the Division to use some other approved or agreed-to technique. Please call if you have any questions. Sincerely, William Agnew` " Sr. Environmental Engineer WA!!b [CDOHVUNEOIJ c: G.M. Stubblefield R.W. Fish B.D. Nicholson Bill Robb, WDB&T J.M. Matter Fred Bant CML U.S. EPA File 109.2.7.3 1 certify under penalty of law that I have examined and am familiar with the information submitted in this correspondence and that, based on my inquiry o[ those persons immediately responsible for obtaining the information contained in the correspondence, I believe the information is true, accurate and complete. 1 am aware there are significant penalties for submitting false information, including the possibility of fine and imprisonment. /R. G.M. Stubblefield Vice President/Operatio s P.0. Box 187 Craig, Colorado 81626 (303) 624-4401