2012-07-10_REVISION - C1981041 (7)

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workings prior to discharge into the Colorado River. A storm water permit and spill prevention containment and control plan associated with the CDPS permit also dictate preventative and mitigation measures for ensuring that all water leaving the mine site meets applicable effluent limits. Receiving stream standards for the Lower Colorado River have been set by the Colorado Department of Health and Environment in their publication "Classification and Numeric Standards for Lower Colorado River Basin." The Colorado River at this point is within segment 2 of the Lower Colorado River sub -basin and basin and Coal Creek is within segment 4 of the Lower Colorado River sub -basin and basin. CDPS permit limitations on discharge, the permit's discharge standards, and the Division's standards for determining material damage to the hydrologic balance ( "Division Procedures for the Assessment of Material Damage with Respect to Alluvial Valley Floors, the Cumulative Hydrologic Impact Assessment and Subsidence at Coal Mines ") are based, in part, on these standards. The Roadside Portal Mines' standards for discharge are listed in Table 2.05.6 A of the permit application. The mines' baseline water quality data is found in Section 2.04.7 of the permit application. The CDPS permit had in the past included a specified salinity standard of not more than one ton per day or 350 tons per year of total dissolved solids, whichever is less. The Roadside Mines salinity discharge exceeds this level, primarily due to mine water discharges. As a result, the operator was required by the Colorado Department of Health and Environment (DOH) to prepare a report outlining possible approaches to reducing the mines' contributions of salt to the Colorado River, and associated costs. This report, "Evaluation of Alternatives for Management of Salt in Mine Water Discharges: Roadside and Cameo Mines; Powderhorn Coal Company; Palisade, Colorado." was completed in February, 1993. Based on the report, DOH made a determination that salt elimination or reduction would not be economically feasible, and granted an exemption from salinity standards (3/17/93 letter, Appen. 17 -2). DOH has not revised that determination, and it remains valid. The Division has granted a number of small area exemptions from the use of sediment ponds due to the limited size of the areas in question and due to the fact that ponds and treatment facilities are not necessary for the drainage from these sites to meet the effluent limitations of Rule 4.05.2 and applicable State and Federal water quality standards for receiving streams and also due to the fact that no mixing of surface drainage from these areas with a discharge from underground workings will occur. The small areas to be exempted are listed in Volume 3, Appendix 13 -3 of the permit application (4.05.2(3)(b)(i)). In 1997, Pond 12 was designed to act as a mine water treatment pond for the mine water discharge associated with the Roadside North Portal Mine, NPDES discharge point 004. Discharge from the North Portal Mine required pumping, which ceased in December 1999 when operations ceased. Outfall 004 has been discontinued and Pond 12 has been eliminated by reclamation operations. Discharge Outfall 015 had been approved for minewater discharge from the South Mine 2 West Portals. The outfall was never activated and the 2 West Portals have been sealed and reclaimed. Only two approved minewater discharge sites remain, both at the South Mine. Outfall 016, located near the North Decline Area is the primary dewatering site. Outfall 002, the siphon discharge system at the reclaimed Northwest Intake Portal, has been retained as a back -up Permit Revision No. 5 21 July 10, 2012