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CCF'HE WC7Cp ~0,, r_~ njgn l May 10 ?~0 13 21 F. 05 ~a~. , ~~_ On November 4, 1999, BMRI purchased the real prooert}', which includes the West~Pit, from ES[. The Rito Seco lies approximately 200 feet south of the West Pit. G. BiviRI's minim operations ceased in October 1996. The original tzciamatiy~n plan included in the CLILRB Permit contemplated leaving the Wesi Pit in an open contiguration with several potential geotechnical measures identified that could enure the long-term stability of the south wall of the West Pit. 7. In the final stages of the mining operation, BMRI proposed to backfill the }Nest Pit. The process of backfilling the West Pit and the anticipated effects of backfilli' ~ on the geochemistry and hydrogeology in the vicinity of the Wes[ Pic were described in detail in Technical Revision ("TR")-18 [o the Ci/ILRS Permit, which BMRI sub fitted to the DMG on February 3, 1994 for approval. On July 20, 1995, the Diti[G conditi pally approved TR-13. 3. On September 1Z, 1996, SMRI received a Final stormwater Permit, Colo ado Dischazoe Permit System, Certification No. COR-040050, which was a renewal c~f the previous permit covering discharges of storrttwater from the San Luis Mine (the , "stormwater permit"). 9. BMRI backfilled the tVest Pit to accordance with TR-18 primazily with aste rock that consisted of Precambrian and Santa Fe Formation materials, to allow f ee drainage of meteoric water derived from precipitation. Backf lling of the West it was completed in .4ugust 1997. 10. The BMRI database for monitoring station RS-5, which is located on th Rito Seco at the downstream property boundary of the San Luis Mine, provides that he fast indication of elevated pollutant (sulfate) levels in the surface water of the Rito eco occurred on October 7, 1997. l [. In the course of a 7uly 1998 groundwater sampling event, monitoring a tivities conducted pursuant to the monitoring plan approved by [he ChiLRB in Techni al Revision No. 15 (TR-15) identified elevated levels of Total Dissolved Solids (TDS") in a groundwater monitoring well, Ivt-11R. In accordance with TR-15 the well s resampled and the elevated TDS levels were confirmed. Siv1RI developed an submitted a Response Plan to DMG on September 2d, 1998. 12. In a letter dated November 2, 1998, from Anne Baldrid~e, BMGC's V ce President of Environmental and Governmental Affairs, Battle Mountain poll ed the Division pursuant to the requirements of Section A of the stormwater permit hat on October 27, 1993, a seep was discovered on the north bank of the Rito Seco owing into the Rito Seco, approximately 200 fee[ downgradient of the reclaimed West P t.