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BLM LIBRARY United States Department of the Interior 88066683 Bureau of Land Management Winnemucca Field Office Winnemucca, Nevada March 2001 Final Environmental Impact Statement Marigold Mine Expansion Project blmubrary BLDG 50, ST-150A DENVER FEDERAL CENTER P.O. BOX 25047 DENVER, COLORADO 80225 BLM MISSION STATEMENT The Bureau of Land Management is responsible for the stewardship of our public lands. It is committed to manage, protect, and improve these lands in a manner to serve the needs of the American people for all times. Management is based upon the principles of multiple use and sustained yield of our nation's resources within a framework of environmental responsibility and scientific technology. These resources include recreation, rangelands, timber, minerals, watershed, fish and wildlife, wilderness, air and scenic, scientific, and cultural values. BLM/WN/PL-01/009+1610 United States Department of the Interior BUREAU OF LAND MANAGEMENT Winnemucca Field Office 5100 East Winnemucca Boulevard Winnemucca, Nevada 89445 (775) 623-1500 http://www.nv.blm.gov/winnemucca In Reply Refer To: 1793/3809 NV-020 March 9, 2001 Dear Reader: This Final Environmental Impact Statement (FEIS) for the Glamis Gold, Marigold Mine expansion, prepared by the Bureau of Land Management (BLM), Winnemucca Field Office is submitted for your review and comment. The FEIS is based on a Plan of Operations submitted to the BLM under 43 CFR 3809 regulations. The FEIS analyzes the direct, indirect and cumulative impacts related to expansion of existing mine facilities (pits, overburden dumps & heap leach pads) and development of the 8-North and 5-North deposits, including construction of new pits, new overburden disposal areas, additional heap leach facilities, new tailing impoundment, drainage diversions, haul and exploration roads, and ancillary facilities Alternatives analyzed include the Proposed Action, No Action, and the 8-South Partial Pit Backfill alternative. The Plan of Operations, Draft EIS (DEIS), and applicable technical reports are available for review at this office. Comments were received on the DEIS during the 60 day comment period, which ended April 10, 2000. Public meetings were held on the DEIS in Winnemucca and Battle Mountain, Nevada on March 8, 2000 and March 9, 2000. This FEIS contains in its entirety the analysis originally presented in the Draft EIS (issued February 11, 2000), with all text changes highlighted. Also included in the FEIS are responses to comments received during the public comment period on the Draft EIS. Comments on this FEIS will be accepted until the close of business April 9, 2001. Written comments or questions may be directed to Jeff Johnson, Environmental Coordinator, at the Bureau of Land Management, Winnemucca Field Office, 5100 East Winnemucca Boulevard, Winnemucca, Nevada 89445. 4b%S> 3°) FINAL ENVIRONMENTAL IMPACT STATEMENT MARIGOLD MINE EXPANSION PROJECT C-W Lead Agency: U.S. Department of the Interior Bureau of Land Management Winnemucca Field Office Project Location: Humboldt County, Nevada Comments on this EIS Jeff Johnson Should be Directed to: EIS Project Manager Bureau of Land Management Winnemucca Field Office 5100 East Winnemucca Blvd. Winnemucca, NV 89445 (775)623-1500 Date Draft EIS Filed with EPA: February 11,2000 Date Final EIS Filed with EPA: March 9, 2001 ABSTRACT Glamis Gold, Inc./Rayrock Mines, Inc., doing business as Glamis Marigold Mining Company (GMMC) proposes to construct new facilities and expand existing gold mining operations at the Marigold Mine in Humboldt County, Nevada. The mine is located on public and private lands near Interstate Highway 80 approximately 13 miles northwest of Battle Mountain and approximately 40 miles southeast of Winnemucca. The proposed Marigold Mine Expansion Project would disturb approximately 462 acres of private land and 255 acres of BLM-administered public land, for a total of 717 acres. The proposed project would include: expansion of two pits and development of two new pits; expansion of two waste rock dumps and development of two new waste rock dumps; addition of lifts to three existing heap leach cells, addition of one cell to an existing leach pad, and development of a new heap leach facility; expansion of the tailings impoundment and construction of a new tailings impoundment; haul roads, solution ponds, growth media stockpiles, exploration drill pads and access roads, and diversion channels; and realignment of a public access road (Buffalo Valley Road) and power line. The Proposed Action would extend the mine operations an additional 5 years through 2007. This Final Environmental Impact Statement provides responses to comments received by BLM during the public comment period on the Draft Environmental Impact Statement (Draft EIS). The Draft EIS analyzed the environmental effects of the Marigold Mine Expansion Project, the 8-South Partial Pit Backfill Alternative, and the No Action Alternative. Responsible Official for EIS: j Terry A. Reed Field Office Manager Winnemucca Field Office ' SUMMARY SUMMARY ALTERNATIVES This environmental impact statement (EIS) analyzes PROPOSED ACTION the direct, indirect, cumulative, and residual environmental impacts of the Proposed Action, Glamis Marigold Mining Company (GMMC) proposes 8-South Partial Pit Backfill Alternative, and the No to construct new facilities and expand existing gold Action Alternative. The alternatives are described in mining operations in Humboldt County, Nevada. The the following sections. mine is located on public and private lands near Interstate Highway 80 (1-80) approximately 13 miles 8-South Partial Pit Backfill Alternative northwest of Battle Mountain and approximately 40 miles southeast of Winnemucca, Nevada. GMMC The 8-South Partial Pit Backfill Alternative would has been operating the Marigold Mine since 1988. include the backfilling of the existing 8-South Pit with Historical mining in the proposed project vicinity dates waste rock originating from the proposed 8-North Pit. back to 1927. To date, approximately 1,349 acres This alternative would eliminate the need to construct have been disturbed. the 8-North Waste Rock Dump (85 acres) thereby decreasing total disturbance to 632 acres. A Plan of Operations Amendment and Reclamation Plan for the proposed Marigold Mine expansion was No Action Alternative submitted to the Bureau of Land Management (BLM) in August 1998. Current mine facilities consist of a Under the No Action Alternative, currently permitted series of pits, waste rock dumps, a heap leach pad operations at the Marigold Mine would cease after and associated processing plant, a tailings 2001, with final reclamation extending 10 years impoundment, access and haul roads, and ancillary beyond closure. Additional minerals in the project facilities. The proposed Marigold Mine Expansion area would remain undeveloped, and no construction Project would disturb approximately 462 acres of or expansion of mine pits, waste rock dumps, heap private land and 255 acres of BLM-administered leach pads, tailings impoundment, or other ancillary public land, for a total of 717 acres. The proposed facilities would occur. project would include: expansion of two pits and development of two new pits; expansion of two waste IMPORTANT ISSUES AND IMPACT rock dumps and development of two new waste rock CONCLUSIONS dumps; addition of lifts to three existing heap leach cells, addition of one cell to an existing leach pad, and development of a new heap leach pad; expansion of A small number of issues were raised during scoping the tailings impoundment or construction of a new for this EIS. Public scoping meetings were held in tailings impoundment; haul roads, solution ponds, Battle Mountain and Winnemucca, Nevada, on growth media stockpiles, exploration drill pads and October 6 and 7, 1998, respectively. Additional issues access roads, and diversion channels; and were identified by resource specialists during the realignment of a public access road (Buffalo Valley preparation of the EIS. These issues along with their Road) and power line. The Proposed Action would impact conclusions are presented below. Impact extend the mine operations an additional 5 years, conclusions include the implementation of mitigation through 2007. Reclamation and monitoring would measures that have been identified. These measures continue through 2017. are presented in detail in Chapter 3.0 of this EIS for each affected resource. SUMMARY Water Resources and Geochemistry Issue: Long-term stability of diversion channels. Issue: Formation of a pit lake as a result of Conclusion: The diversion channels would be mine development and impacts to designed and constructed to wildlife from degraded water quality. accommodate a 100-year storm Conclusion: The construction and development of event. the 8-North Pit would not occur unless the price of gold is $400 per ounce or Issue: Degradation of surface water from heap leach expansion and tailings greater. If the pit is developed, it impoundment. would only be mined to a depth that would not intercept groundwater; no pit lake would form. Conclusion: Perennial streams and springs do not exist within the project area. Issue: Impacts to surface water and Intermittent creeks exist within the project area and convey water only groundwater levels resulting from pit during seasonal snowmelt or heavy dewatering and groundwater use for mine operations. precipitation events. Heap leach facilities and the tailings impoundment Conclusion: Based on the evaluation of historic would be designed to contain potential contaminants (e.g., cyanide solution). and current groundwater level data These facilities would be closed within the project vicinity, hydrologic impacts to springs or intermittent systems with no release of solutions to areas outside the facilities. creeks located in the project vicinity Therefore, no impacts to surface are not anticipated. Springs and water are expected. intermittent creeks located in the project vicinity would not be affected since the water source for the springs Issue: Degradation of groundwater quality. and intermittent creeks is not hydrologically connected with the Conclusion: Geochemical testing indicates that bedrock aquifer. No pit dewatering is waste rock from the mine does not anticipated during mining. Water used have a potential to generate acidic for the proposed mine operations seepage. Seepage from waste rock would be obtained from the Lone Tree dumps may be elevated in arsenic and mercury, but would not be Mine and supplemented with the water from water supply wells in the expected to reach groundwater due to project vicinity. The source of water the low permeability of the soil and the for the water supply wells is mainly depth to groundwater (about 80 feet). the bedrock aquifer, whereas the The current tailings remediation plan source of water for the springs and at the existing tailings impoundment is intermittent creeks is shallow expected to reduce seepage to alluvium and surface flows resulting groundwater and keep any impacts to from runoff. groundwater within State drinking water standards. A new tailings impoundment may be constructed if the 8-North and 5-North Pit deposits are mined. This impoundment would have a low permeability base SUMMARY consisting of compacted clay or a infestations during mine operation and geosynthetic liner. reclamation. Issue: Utilize native species in reclamation Air Quality seed mixes. Issue: Cumulative impacts to air quality. Conclusion: The interim seed mix would include crested wheatgrass, which is a non-native species. This species Conclusion: The annual and 24-hour contributions would be used since it readily from the mine sources would not establishes on disturbed sites and cause the air quality in the region to degrade below National or State reduces soil erosion. The ambient air quality standards. permanent reclamation seed mix to be used during reclamation would consist primarily of native species. Vegetation Resources These mixes were developed as a result of past and current revegetation studies and successful reclamation Issue: Loss of wetland or riparian areas conducted at the mine site. resulting from the construction of the diversion structures. Issue: Reclamation of the proposed tailings impoundment. Conclusion: Wetlands or riparian areas would not be affected within or adjacent to the Conclusion: GMMC has committed to reclaim the project area. proposed tailings impoundment area after mining operations cease. After Issue: Potential long-term impacts to the reclamation has been completed, the Humboldt River and wetlands near its area would be monitored for several terminus. years to evaluate reclamation success. Conclusion: The project area does not include perennial creeks or rivers. Therefore, no impacts to the Humboldt River or wetlands located adjacent to the river Wildlife and Fisheries Resources would be affected by mine expansion. Potential impacts to groundwater and Issue: Wildlife habitat disturbed or lost. surface water would be limited to the mine site and immediate vicinity. Conclusion: No riparian habitat would be affected. Loss of upland habitat would not Issue: Minimize the spread of noxious exceed 717 acres. The value of weeds. habitat lost would be low to moderate, due to the proximity of the project to Conclusion: GMMC has committed to use seed past and present disturbances and that has been tested for noxious activities and the availability of native weed seeds prior to application, habitats in the surrounding region. and control or eradicate any weed Approximately 656 acres of disturbed habitat would be reclaimed. SUMMARY Issue: Loss of mule deer winter range. Special Status Species Conclusion: A total of 717 acres of mule deer Issue: Potential impacts to special status winter range would be removed for species. the life of the project. Conclusion: With the exception of sensitive bat Issue: Direct mortalities, habitat species, no sensitive plant or wildlife fragmentation, and animal species would be affected. The displacement. implementation of the committed environmental protection measures Conclusion: Direct mortalities would be limited. would minimize impacts to sensitive Incremental habitat fragmentation bats. would occur and terrestrial wildlife would be displaced for the life of the project. Range Resources Issue: Impacts to resident and migratory Issue: Loss of available grazing land and birds. interference in ranch management activities resulting from the Conclusion: Potential effects to breeding birds construction of the range perimeter (e.g., passerines, raptors) could occur fence. from incremental habitat loss, disturbance to nesting habitat, and Conclusion: Construction of the range perimeter increased noise and human presence, fence would remove 5,762 acres of particularly from mine exploration rangeland available for grazing activities. These impacts would be resulting in the temporary loss of minimized by the applicant committed 288 animal unit months. A permanent protection measures. Effects to loss of 6 animal unit months would upland game birds would be minor, result after mine reclamation. based on relative habitat value, bird species occurrence, and committed Issue: Construction of the diversion protection measures. structures may affect water available for livestock. Issue: Measures to prevent wildlife exposure to cyanide solutions on heaps, in Conclusion: Segments of Trout and Cottonwood solution channels, and ponds should creeks located within the project area be developed. have intermittent flows and are used by livestock as seasonal water Conclusion: Potential impacts from cyanide sources. The construction of the ingestion would be low, since bird diversion structures would alter the netting would be installed over the configuration of these creeks. solution ponds and GMMC would However, these creeks would still be monitor heap leach pads to avoid available for seasonal use by livestock the puddling of cyanide solution during mine operation. In addition, Ames and Mud springs are located within the general vicinity of the IV