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APR-20-2000 TNU OS:50 PM RMC • I0:3036656959 ROCKY MOUNTAIN CONSULTANTS. INC. April 20, 200D Ms. Lori Potter Kelly~Naglund~Garnsey + Kahn, LLC 1441 Eighteenth Street, Suite 300 Denver, Colorado 80 2 02-1 2 5 5 FAX KO Rf~O'00 P, 08 16:29 No .010 P,02 Inc Premiere Bullding 825 Delawore Ave.. Sulto 600 Longmont CO 80501 (303) 172.5282 Metro (303) bb5-6283 FAX (303) 665-6959 (Brsf INllal, last name)®lonq.rmcco.com Re: March 1, 2000 Document Long-Term Water Qpalfty Standards and Monitoring fn the Vicinity of the West Pit, San Lufs Projec(, Castilla County, Colorado Dear Lori: Rocky Mountain Consultants, Inc. (RMC) has reviewed the above-referenced document (referred to herein as TR-028) prepared by Shepherd Miller, Inc. Ior Battle Mountain Resources, Inc, (BMRI). First and foremost, we believe that issuance of this document Is premature. The West Pit pump and treat sysiem has been active less than one yeas and the wells in the West Pit, BF-3, -4 and -5, have only been steadily pumped since January 2000. Importantly, the system has not been operated during a spring runoff period when groundwater levels and pit inflows should be at Iheir highest. finally, the pilot Pink Gneiss in-situ microbiological water treatment system, which presumably will be employed at the West Pit if the pilot test yields promising results, has not been installed. The groundwater monitoring program proposed in TR-028 Is '...robe implemented as part ofthe /;na closure of the TR-026 water management program" (see TR•028, page 1, paragraph 1, last sentence), The West Pit water management system has not operated through a complete hydrologle cycle, nor has the in-situ remediation system been tested. Therefore, we believe it is premature for the Division o/Minerals and Geology (DMGI to have requested that BMRI develop such a plan. Continued data collection under the monitoring program proposed in Section 6.4,2 of TR-026 (plus additional monitoring locations specified by the DMG, such as well MW-34) are recommended before a post TR• 026 closure groundwater monitoring plan is developed (we do prefer the expanded analytical suite proposed in TR-028 over that in TR-02G). We believe that there are still too many unknowns surrounding the final West Pit closure to adequately design apost-closure monitoring program. The monitoring that BMRI proposes in TR-028 has a major effect on the environmental monitoring plan proposed fn TR-026. As It is proposed, we believe that the monitoring locations identified in TR- 02Bare insuf(iclent to protect the waters of the State. There is only one backfill well and one curtain well included on the Iis1. The West Pit backfill material is the source of the contamination currently impacting the Rito Seco and the Rito Seco alluvium, More than one backfilf well should 6e monitored to provide early warning of future deterioration of water quality in the West Pit. 1n addition, the curtain wells serve as the first line of defense in detecting poor quality water as it (eaves the pit and enters the Rito Seto alluvium. As stated on page 5 (fvu paragraph, fourth sentence), there is "potential heterogeneity of the (Kilo SecoJ alfuviaf aquifer ." How can BMRI verify that contaminated water, if any, moving out of the West Pit would be detected at well M-19t More curtain wells should be included in tfie monitoring program. In summary, the proposed TR-026 monitoring program is reactive. By the time most wells would detect groundwater contamination, the contamination would CIVIL ANb ENVIRONMENTAL ENGINEERING PLANNING