EXECUTIVE SUMMARY The Bureau of Land Management (BLM) Winnemucca Field Office (WFO) is in the process of preparing an overall Resource Management Plan (RMP) for the Field Office (FO). As part of the RMP revision process, the BLM is required to prepare a Mineral Assessment Report providing information regarding mineral occurrences and potential within the WFO RMP Planning Area (Planning Area). This report provides an intermediate level of detail for mineral assessment as prescribed in BLM Manual 3060 (BLM 1994). The information presented in this report will be summarized and incorporated into an Environmental Impact Statement (EIS) for the proposed RMP and into the final RMP. The geologic history of northern Nevada and the Winnemucca FO Planning Area (Planning Area) is very complex, and includes two major cycles of sedimentation (western and eastern facies sources), episodic thrust faulting, mountain building and associated intrusive and igneous activity. More recent geologic history includes a period of crustal extension that was accompanied by bimodal (rhyolite-basalt) volcanism, basin and range block-faulting, resulting in high-levels of shallow crustal heat flow. The regional and local geologic setting has been instrumental in the location of and significant potential for the numerous economic metallic mineral deposits in the Planning Area, as well as the significant potential for the development of economic geothermal resources. LOCATABLE MINERALS The Planning Area has a long history of mineral development dating back to the 1860s and contains some of the most famous gold and silver metal mining districts in the US, including: Battle Mountain, Potosi, Marigold, Lone Tree, Getchell, Pinson, Seven Troughs, Awakening, and Hog Ranch (Davis and Tingley, 1999; Peters and others, 1996; and Wallace and others, 2004). Locatable minerals historically or currently mined within the Planning Area include metallic minerals (i.e.: gold, silver copper, mercury, zinc, molybdenum, manganese, uranium, tungsten, etc.) and non-metallic minerals (i.e.: limestone, barite, gypsum, diatomaceous earth, sulfur, fluorspar and opals). Currently there are ten (10) large open pit gold / silver mines, and six (6) other industrial mineral mines in operation in the Planning Area. Over fifty (50) mining plans of operation and 102 notices are currently administered by the WFO. A total of 2,213 mining notices (as of Nov. 29, 2005) have been administered by the BLM since 1981 and nine (9) are current pending decisions. The US Geological Survey identifies more than 1,400 bedrock mines and prospects in the Planning Area, seventy eight percent of which occur within existing established historical mining districts (Sherlock and others, 1996). Mineral exploration particularly for gold is an ongoing enterprise in Nevada by both operators of existing mines and by other exploration companies. Exploration has been extremely active recently (2004-early 2006) as gold prices have sustained levels above $400/ounce, and exceeded $600/ounce in early 2006. Companies conducting exploration in Nevada in 2004 reported spending some $79.7 million in 2004 (Dreisner and Coyner, 2005). Exploration in large part takes place in areas near known mineral deposits and within historic districts; however, Final Mineral Assessment Report –Winnemucca Field Office, BLM September 2006 Page ES-i exploration is also conducted in other outlying areas that the mineral industry considers prospective for various reasons (Wallace and other, 2004). Nevada’s total mineral industry production was valued at $3.3 billion in 2004 and precious metal production accounted for about $3 billion of this total (Driesner and Coyner, 2005). Prospects for sustaining these production rates in the short run are excellent and also quite likely in the long run (15-20 years). Based on mining industry projections it appears that market conditions for gold will remain relatively consistent, with gold priced at sustainable levels in the $400+/ounce range. Within the next 10 years it is anticipated that 2-3 currently active mines will go into closure and be reclaimed. These mine closures would likely be offset with both new projects being developed and placed into production, and the expansion of existing mines. A significant increase in exploration and mining activity has occurred with increasing metal commodity prices, placing additional demands on permitting and regulatory compliance agencies. This increased activity has also increased the potential adverse effects on watershed and other resources in the planning area. Most of the effects are site specific and potential impacts are minimized by the requirement for environmental analysis during permitting of proposed exploration and mining activities. Other state and federal regulatory requirements include mitigation measures to reduce real or potential impacts, requirements for reclamation and long term closure planning. There are no large scale commercial placer operations currently operating in Nevada (Fitch 2003) and it is likely that most major placer deposits have already been discovered and developed in the past. Most modern placer mines operate under “Casual Use” criteria and involve individuals or clubs that mine at a small scale using little or no equipment other than hand tools and sluice boxes. Larger scale operations typically mine 60 to 150 ounces (1.7 to 4.3 kilograms) of gold per year under a Notice and are permitted to use mechanized equipment. These types of operations are often restricted and have mitigations in place to protect other resources. Site reclamation work is bonded by the responsible permitting agency to insure completion. The Planning Area should likely anticipate 10 operations operating under a Notice during any given year, with the actual number being a function of the price of gold. Gems and semi-precious stones will likely continue to be mined on a small scale in the Planning Area. Deposits are small, usually hand-operated as “pay-to-dig” operations, and great care must be taken when extracting the stones so as not to damage and devalue the pieces. Existing deposits will likely be extended and remain small with labor intensive mining methods. While pluton-related and epithermal deposits hosting gold and silver are commonly associated with metals other than gold and silver, the potential for development of these metals, such as antimony, beryllium, iron, lead, manganese, mercury, uranium, and zinc is low to very low. Potential for copper production is also low with the exception of moderate to good potential for further development of at least one massive sulfide copper deposit at the Big Mike Mine within the Planning Area. Final Mineral Assessment Report –Winnemucca Field Office, BLM September 2006 Page ES-ii There is no current production, nor has there been any significant historic production of molybdenum from the Planning Area, however, it seems quite likely that the Ashdown Property could be brought into production as a low-fluorine molybdenum porphyry system within the next few years. Other molybdenum deposits may be also developed over the next 15-20 years as well. There is a moderate potential for the development of tungsten deposits within the Planning Area. The price of tungsten (WO3) has increased significantly in the last few years and has stimulated the production of tungsten elsewhere in the world where deposits are larger and higher grade than those found in Nevada. It would seem reasonable that if prices were to remain high and demand increases somewhat, that some companies might be encouraged in attempting to bring some of the larger, higher grade deposits of the Planning Area into production. Locatable industrial mineral deposits of dolomite, gypsum, diatomite and perlite are currently mined within the planning area. Low to moderate potential exists for production of most locatable industrial minerals, however, potential is good for production of carbonate (limestone and dolomite), diatomate, and gypsum from the Planning Area where deposits are located near transportation corridors and are mineable by inexpensive open-cut methods. The Echo Canyon Limestone mine is scheduled to begin production in the near future and is located northeast of Lovelock, east of the Humboldt River and Interstate 80. SALEABLE MINERALS Saleable mineral extraction and use will increase along with increasing mining activity, commercial development, recreation activities, and private property development, especially along the Interstate 80 corridor within the Planning Area. The minerals program administers 65 active sales, 112 free-use permits and 168 mineral site rights-of way. Saleable mineral sites with a priority for use will likely include sand, gravel, and rock quarries located along State, County, and BLM managed roads. There is good potential and considerable demand for continued development of aggregate deposits in the Planning Area. Virtually all of the basins/valleys in the Planning Area have potential aggregate deposits but those deposits adjacent to their end uses or good transportation corridors will have the greatest development potential. There is good potential for new and continued development of existing clay deposits in the Planning Area. Mining of clay deposits was and is being conducted throughout the Planning Area. There is low potential for development of pumice and cinder deposits although there are a number of occurrences and former mines within the Planning Area. Currently, pumice deposits are not being mined