1990-10-31_REVISION - M1988112 - Laserfiche WebLink

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Governor Roy Rome Costilla County arl>f Battle Mountain Resources October 31, 1990 Page Three Environmental Issues While the land use issue must be addressed at the local-government level, the state does have responsibility for a number of the health, safety and environmental concerns you raised. uuc~ Luc ~a~~n,vo umw ,va.a ~cu witurn Inc iuu-rca~ iouvuvia n~ pose a threat to the community of San Luis? The tailings disposal facility is not a true tailings pond. The mill reject, or tailings, are deposited in a relatively dry condition. The tailing disposal facility, currently under construction, is located about 4,000 feet south of the Rito Seco and about 200 feet higher in elevation. In addition, the facility is located south of a topographic saddle while the Rito Seco lies north of the saddle. The tailings facility is not in the 100-year floodplain of the Rito Seco. There is no mine or mill-related threat to the Town of San Luis from a significant flood event on the Rito Seco. The Mined Land Reclamation Division is currently conducting its second inspection of the site this season. The division will continue to evaluate the construction of the tailings disposal facility do ensure it is constructed in accordance with the approved mining plan. contamination orooiemt we are conriaent roar Lnere will oe no aoverse environmental or health effects from the tailings piles during or after mining. The MLRB approved a tailings disposal plan which stages that cyanide content of the tailings will not exceed four (4) parts per million upon deposition. In other words, cyanide content will be reduced from sixty (60) parts per million to four (4) parts per million before the tailings can leave the enclosed mill facility. Cyanide is a naturally unstable compound, and is readily decomposed in sunlight. Upon deposition, the cyanide content is expected to be further reduced due to natural degradation. Water pollution will not occur as the tailings facility will be underlined by compacted earth and impermeable plastic. The tailings material will consolidate over time from the bottom up to form another liner system. The tailings facility is designed to contain all cyanide solutions on site, as well as rainfall from a major storm event, without discharging any water to the environment. The Mined Land permit requires that air pollution due i~o blowing tailings be minimized. This will be accomplished by having eii:her water trucks or high-volume sprinklers maintain the surface moisture of the tailings.