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\~ - , _ l~l-r. t ~ J III IIIIIIIII IIII III 999 STATE OF COLORADO Roy Romer, Governor Patti Shwayder, FxecuMe Director Dedicated to protecting and improving the health and errvironment of the people o/Colorado 4700 Cherry Creek Or. 5. Laboratory Building Denver, Colorado 80222-1530 4270 E. 11th Avenue Phone p03) 692-2000 Denver, Colorado 80220-3716 ~ E C E I ~~ (7 0 31 691-4 7110 January 28, 1997 JAN 3 01997 Ms. Kathleen G. Welt Mountain Coal Company P.O. Box 591 Somerset, CO 81434 Division o1 Muieiaio ~ ~~~o~oSY Re: Your Letter dated January 27, 1997, Request for Bypass - Mountain Coal Company -West Elk Mine CDPS Permit No. CO-0038776; Gunnison County, Colorado Deaz Ms. Welt: o4~cO~o R~ 4 Ne .Q a Colorado Depuunent of Public Health and Envitonmwt The WQCD received the above-referenced letter on January 27, 1997, via facsimile. th the letter, MCC proposes temporarily bypassing treatment ponds to directly discharge water collected from behind the "sealed" fault area and piped to the surface. From the letter and this morning's telephone conversation, I understand that MCC believes that the bypassed mine water will mcet the TS5 and other effluent limitations imposed at the permitted outfalls. The WQCD approves of the short-temr bypass as long as the following conditions are met: • The mine water is sampled from behind the seal for all tpe same parameters required at MB-l's Outfal1002 and the results indicate the discharge will comply with all effluent limitations prior to discharge. Please remember that 30~ay average limitations must be md. • MCC advises the WQCD when the bypass is initiated and terminated, and provides updates daily for the first three days and weekly thereafter. • The bypassed water is sampled twice daily at the pipe outlet, independently from any other discharges. This effluent must mcet all the same effluent limitations specified for outfalls 002 and 004 independently of the others and should not be reported together with pond MB-1 or any other discharges. [f at arty time effluent limitations are not met, the bypassed discharge must cease as soon as practical without temperatlrre- shocking the fish; and the WQCD must be notiLed. • ,MCC must initiate and disconunue the bypass flows in a staged manner topreventtemperature-shocking the fish th the receiving stream. The maximum allowed rate of instream temperature change is 0.5 °F per hour, up to a maximum total temperature change of 2°F, as measured comparing temperatures 100 feet upstream to 100 feet downstream of the bypass discharge. Please measure instream temperatures each half hour until MCC is llischazging from the bypass at maximum flow rates, then MCC may conduct twice daily sampling, if there is no danger of exceeding the aforementioned criteria. If at any time these temperature conditions aze not met, the bypassed discharge must be decreased as soon as possible without temperature-shocking the fish by not exceeding the maximum allowed rate of instream temperature change of 0.5°F per hour. Approval is based upon MCC's discharges through outfalls 002, 004, and the bypass comprising no more than 3% of the total stream flow.