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. ~: iiiiiiiiiiiiiiuiii STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY Department of Natural Resources 1313 Sherman 51., Room 215 ~ Denver, Colorado 80203 I~~~ Phon : 1 3031866-3567 e p FAX. 1 AP[i~ ~, D~996 DEPARTMEN"I' OF NATURAL Mr. Robert Shukle RESOURCES Colorado Department of Public Health and Environment Roy Romer Water Quality Control Division c°ver"°r 4300 Che Creek Drive South ny lames Lnc6nead E>tecwrve Direnur Denver, CO 80222-1530 Michael B Lonb Division Duecroi RE: Alternate Effluent Limits for Pit Pumpage During our meeting with Colowyo last week, there was some discussion about whether the discharge sample collected by Erica Crosby of our office should meet the TSS effluent limit in Colowyo's CDPES permit, or if the alternate settleable solids limit for precipitation events applied. It is important for DMG to have an answer to this question since the lab results of Erica's water sample are expected to be in excess of the TSS standard. The memorandum of understanding between our agencies indicates that when DMG receives an analysis of a water sample collected by our inspectors, DMG shall determine whether a violation of the coal regulations has occurred, "as determined by comparison with federal effluent limitations guidelines found at 40 CFR Part 434". As you may recall, Erica collected a sample of water which was leaking out of the East Taylor Creek sediment pond at the Colowyo Mine on March _, 1996. Most of the water in the pond had been pumped from the mine pit by the operator. According to the operator, there was a small inflow to the pond as a result of snowmelt at the time the sample was collected. Following our meeting with Colowyo at your office last week, I did a little follow-up in regard to the question of alternate effluent limits during precipitation events as they relate to water pumped from surface mine pits. I reviewed 40 CFR Part 434 and the Federal Register discussion relevant to those regulations (50 FR 41305, Oct. 9, 1985). Based in part on the following excerpts from 40 CFR Part 434, and the federal register, I do not believe that water pumped from a mine pit qualifies for alternate effluent limits during precipitation events. Please let me know if you agree with my interpretation of the rule and Federal Register discussion. "The term 'controlled surface mine drainage' means any surface drainage that is pumped or siphoned from the active mining area." (40 CFR Part 434.11(q)). Appendix A to Part 434 contains a table delineating which effluent limits apply to which discharges under differing precipitation regimes. Line 3, for controlled surface mine drainage, indicates that TSS, pH, Fe and Mn limits apply to all controlled surface mine discharges unless an event greater than a 10-year, 24-hour storm occurs.