2017-05-11_PERMIT FILE - C1981012 (18)

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In TRIM COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division Fact Sheet- Page 20, Permit No. C00000906 monitoring requirement was added to the permit for the collection of data to support future RP determinations. Total Recoverable Iron For outfalls 001, 007, 008 and 010, a qualitative RP determination has been made because effluent Limitations for total recoverable iron are included in the federal ELG for Alkaline Mine Drainage (Subparts B and D), indicating this pollutant is expected in the discharge at levels which may cause or contribute to an exceedance of the water quality standard. Outfall 001: the 30 -day average WQBEL of 1471 pg/l applies to the discharge as it is the most stringent limitation. This limitation is more stringent than the previous limitations; therefore, a compliance schedule with interim limits based on the federal ELG is included in the permit. As previously discussed, the permittee is required to meet the federal ELG 30 -day average (3000 pg/l) and daily maximum (6000 pg/l) limitations immediately and through the term of the compliance schedule. Note that the applicable alternate limitation through the end of the compliance schedule is based on the previous permit limitation. Outfalls 007, 008, and 010: the 30 -day average WQBEL of 1000 pg/l applies to the discharge as it is the most stringent limitation. This limitation is more stringent than the previous permit limitations; therefore, a compliance schedule with interim limits based on the federal ELG is included in the permit. As previously discussed, the permittee is required to meet the federal ELG 30 -day average (3000 pg/t) and daily maximum (6000 pg/l) limitations immediately and through the term of the compliance schedule. Note that the applicable alternate limitations through the end of the compliance schedule for outfalls 007 and 008 are based on the previous permit limitation. Potentially Dissolved Lead At outfall 001 the RP analysis for lead was based upon facility data and the WQBELs and ADBACs as calculated in the WQA. The MEPC was less than half of the MAPC and therefore limitations and monitoring are not required. At outfalls 007, 008, and 010, a qualitative determination of no RP was made as lead identified in the ELG development document as a parameter with no or limited detects (i.e., less than 20%). Potentially Dissolved Maneanese A quantitative RP analysis was conducted for outfalls 001 based on the WQBELs and ADBACs as calculated in the WQA. A qualitative RP analysis was conducted for outfalls 007, 008, and 010 as manganese is identified in the ELG Development Document as a parameter that can be found in alkaline coal -related discharges. Outfall 001: the MEPC was less than half of the MAPC and therefore limitations are not necessary at this time. However, because the parameter is identified in the ELG Development Document, a qualitative monitoring determination was made to ensure that sufficient data is available to support future RP determinations. Therefore, a semi-annual monitoring requirement is included in the permit. Outfalls 007, 008, and 010: a qualitative monitoring determination was made because the outfalls convey surface flow from the active mining area. The treatment provided by sedimentation ponds approved under the SMCRA authority are not expressly designed for all pollutants regulated under the WQCA, including metals removal, and for outfall 010, no treatment technology is implemented. A semi-annual monitoring requirement has been added to the permit for these outfalls for the collection of data to support future RP determinations. Total Recoverable Molybdenum There are no data regarding the presence/ absence or quantification of this parameter in the discharge from any of the facility outfalls. Sources of molybdenum are primarily industrial processing and molybdenum mining. As molybdenum is not generally associated with coal mining, a qualitative determination of no RP has been made. Total Mercury A quantitative RP analysis was conducted for outfall 001 based on the WQBEL and ADBAC as calculated in the WQA. A qualitative RP analysis was conducted for outfalls 007, 008, and 010 as mercury is identified in the ELG Development Document as a parameter that can be found in alkaline coal -related discharges.