REP36827 - Laserfiche WebLink

Home Browse Search

1 1 HomestaAe Mining Company -Bulldog Mine-Lower Tailing Pond 2.0 BACKGROUND & HISTORY OF THE LOWER TAILING POND The Bulldog Mine property is located in southwestern Colorado in Mineral County, neaz ' the community of Creede (Figure l ). The Bulldog Mine, was one of several underground mining operations that comprise the historic Creede Mining District. HMC reopened the mine in 1970 when de-watering was initiated in the historic underground workings. A silver concentrate was ' produced until 1985, when production was curtailed due to low silver prices. During operations, tailings produced at the mill was either used as backfill in the underground workings or placed ' into one of two tailing disposal facilities, the Upper and Lower Tailings Impoundments. The Lower Tailing Impoundment, the lazger of the two facilities, was located 1.5 miles south of the Bulldog Mine. It was constructed in 1974 and received non-cyanide tailings starting in late-1974 ' and cyanide tailings in 1978. In 1978, surface seepage began to appear down-gradient from the Lower Tailings ' embankment. In response, HMC installed a seepage collection system to accumulate the surface seepage and return it to the pond. From 1978-1980 HMC continued to monitor the seepage problem and, at the direction of HMC, Envirologic Systems Inc. of Denver, Colorado, installed ' a series of piezometers in and down-gradient from the embankment to monitor the seepage. Based on the results ofthis monitoring and the seepage being collected and returned to the pond, in 1980, a second step in remediation was implemented when seven -12 inch "interceptor" wells were installed down-gradient from the embankment to collect seepage. In December 1980, this seepage recovery system was abandoned, primarily because the submersible pumps that were installed were not capable of pumping the fine sand that had been drawn to the wells. ' In March 1981, D'Appolonia of Denver, Colorado was retained to evaluate the seepage problem and to design a corrective action program. A Phase 1 Remedial Action Plan was ' provided in June 1981 and a Phase 2 Plan in October 1981 that documented the history of pond seepage and the geologic conditions responsible for the seepage. In March 1982, the MLRD wrote HMC stating a concerns for the seepage problem and requesting a plan to resolve the ' problem. In May 1982, HMC requested proposals for construction of the remediation program as described in the D'Appolonia Remedial Action Plans. The contract was awazded to D'Appolonia on June 21, 1982 ' The 1982 ground water remediation work at the Lower Tailing Impoundment consisted of the following: ' The construction oja slurry cut-off wall down-gradient from tailings embankment; • the construction oja drainage trench and pump-back system, • the installation ojtwo monitoring wells at the toe of the tailings embankment and three monitoring wells down gradient from the slurry cut-ofjtivall, and ' the selective (test) grouting of the deep channel below the embankment. I