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CCFHE 61CCD ~ax ~O }-'r?2-0090 Mau 10 ~0 1;, 21 ~ F. n4 13. Three other surFace expressions of the seepage front described in the November 2, 1998, letter were subsequently discovered flowing from the north bank of the Rito Seco during inspections by the U.S, Environmental Protection Agency and a site visit b members of the Castilla County Conservancy Distritt. 14. BMRI submitted a revised Response Plan to DMG in November 1993. The revised Response Plan required a site specific hydrological characterization of the area surrounding the backfilled Wesi Pit to identify the potential causes of the elevated TDS levels and the development of response measures. On January 26, 1999, the CML approved the TR-1 S Response Plan as a part of a legally enforceable Board order. Under the requirements of the Board order, BivtRl submitted an interim report on Februa~ 16, 1999, which described the status and results of [he hydrologic characterization an identified response options potentially available. 15. On March 22, 1999, BbtRI submitted a final report in the form of a Techn~cal Revision to the CMLRB Permit (TR-26) which provided a detailed hydrological characterization of the West Pit area and a technical proposal for water managem nt response activities for the site. These response activities included both interim an long term water management and treatment measures. TR-26 states that, following pla emenc ofbackfill materials into the West Pit, groundwater inflow from the three contrib ling aquifers began to saturate the backfill materials. Initially, all groundwater flow ved towards the West Pit. Eventually, the goundwater level in the backfilled pit rose to en elevation such that the hydraulic gradient was re-established from the backfilled it toward the Rita Seco alluvial aquifer. TR-26 concludes that sulfate and mangane a were leaching from the backfilled materials in the Wesi Pit and that goundwater coot ping elevated levels of sulfate and manganese was migrating from the West Pit to the ~to Saco alluvial aquifer. 16. On June I, 1999, BMRI received partial approval of TR-26 from the DM for the construction and implementation ofa pumping and evaporation system to Comm nce reduction of the groundwater levels in and around the West Pit. This system was constructed and commenced operation in July 1999. On a parallel course, BMRI conducted water treatment bench scale and pilot tests anticipating active water [r atment would be required to continue the water management activities contemplated in R-Z6 during the winter season. 17. On August 20, 1999, the Division issued a Notice of Violation and Cease and Desist Order ("NOV-CDO") to SMRJ and B~~1GC for violations of the CWQC A copy of the NOV-CDO is attached as Exhibit A and is incorporated by reference herein. 18 On August 20, 1999, BMRI filed an application for a Colorado Discharg Permit System ("CDPS") Permit for [wo types of discharges, with the Division. The di charges specified in this application included the discharge proposed from a water treat ant system designed to treat groundwater from the West Pit and surrounding area (d scharge point 001) and the discharge from the seepage front in the alluvial groundwater hich resulted from groundwater flow from the West Pit (discharge point 002).