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By Phillip R. Moyle

In 1985 the U.S. Bureau of Mines evaluated the mineral resources of the Sheep Creek West Wilderness Study Area (ID-111-36A), Owyhee County, ID, for the U.S. Bureau of Land Management. The Wilderness Study Area consists of 11,680 acres centered approximately 20 miles south of Grasmere, 10. It contains no mines, claims, or prospects. No mineral resources were identified; however, a geode occurrence within and adjacent to the Wilderness Study Area, and minor amounts of placer gold along Sheep Creek, may be of interest to rorkhounds and recreational gold panners.

Jan 1, 1986

By Donald O. Capstick

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Jan 1, 1983

By Francis E. Federspiel

In 1984 and 1985, at the request of the U.S. Forest Service, the U.S. Bureau of Mines examined the 87,720-acre South Boise Yuba study area (formerly known as RARE II Wilderness Recommended area I-4553) to evaluate mineral resources. The study area and additions are in Blaine, Camas, and Elmore Counties, 10, about 60 mi east of Boise. Granitic rocks of the Cretaceous age Idaho Batholith occupy the western two-thirds of the study area. A Tertiary age granitic complex has intruded, and broken into small blocks, Paleozoic age sedimentary rocks in the eastern third of the study area. Tertiary Challis Volcanics overlie both of these rock types. Principal mineralized structures are gold-and silver-bearing quartz veins and shear zones trending northwest to easterly in the Cretaceous granitic rocks. Copper, lead, and zinc are accessory metals in many mineralized structures.

Jan 1, 1987

By Jerry E. Olson

In 1984, the U.S. Bureau of Mines conducted a mineral survey of the Black Rock Desert Wilderness Study Area (WSA) (NV-020-620), which covers approximately 319,000 acres in Humboldt County, Nevada. About 90% of the WSA is underlain by Pleistocene desert playa sediments; the remainder is comprised of Jurassic-Triassic metamorphic rocks, a Cretaceous intrusive and Tertiary volcanic rocks. Most of the WSA is within a down-dropped fault block of the Basin and Range physiographic province. No mines or evidence of major exploration were identified within the WSA; but five claim blocks within or adjacent to the WSA and zones of anomalous character as defined by the Bureau of Land Management were examined. No mineral resources were identified, but anomalous gold, silver, and indicator element content of samples taken near Pinto Hot Springs indicate resources may exist. Lithium content of samples from near-surface sediments on the desert playa is too low for resources, out geologic conditions are favorable for higher concentrations at depth. Occurrences of zeolites are not considered to be of commercial interest. Approximately 27,000 acres are held under geothermal lease, and most of the WSA is of interest for oil and gas. No evaluation of these commodities was made by the Bureau of Mines

Jan 1, 1985

By Ronald T. Mayerle

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied a 20,500-acre part of the 104,085-acre Rincon Wilderness Study Area (OR-002-082) in order to evaluate its identified mineral resources. The wilderness study area is located in Harney County, OR, about 12 miles west from Fields. No mineral resources were identified within the study area. A literature search found no records of mining or minerals exploration, nor did a ground search find any evidence of mining-related activity. Of seven alluvial samples taken from the major drainages of the study area, all were barren except one. This sample, taken from a dry streambed along the southern boundary, contained $0.07 gold per cubic yard; however, this small amount of gold is of no economic significance, and the source is probably outside the study area. The Pueblo-Steens mining district extends to within 4 miles east of the study area. No evidence of geological environments similar to those that were responsible for the formation of resources or occurrences of metals and nonmetals within the district is known within the study area.

Jan 1, 1987

By J. Mitchell Linne

The principal mineral commodity in the Orleans Mountain RARE II area (No. 35019) is gold. Gravel deposits along the Salmon River contain placer gold. Lode gold with associated silver is contained in quartz veins. Many placer mining claims have been located within the study area in the Salmon River district. Four placer patents totalling 230 acres were issued for claims on the Salmon River between Lewis Creek and Forks of Salmon. On this same reach of river, adjoining and overlapping the study area boundary, approximately 3.3 million cu yd (2.5 million cu m) of gold bearing gravel with values ranging from $0.51 to nearly $5 per cu yd (50.66 to $6.50 per cu m) (gold valued at $400 per troy oz), are contained in three placers, the Bloomer, Pot Luck, and Horn (table 1). Within the study area boundary there are approximately 950,000 cu yd (726,000 cu m) of gold bearing gravel in these three placers. These three mines yielded nearly 12,000 oz (373,000 g) of gold and more than 300 oz (25,000 g) of silver between 1872 and 1913.

Jan 1, 1982

By Clayton M. Rumsey

The U.S. Bureau of Mines conducted a mineral resource survey of the Cinder Cones Wilderness Study Area (WSA) (CDCA-239), 10 miles east of Baker, CA, in 1983. The 44,299-acre WSA is underlain by Precambrian granite gneiss, Upper Cretaceous or lower Tertiary Teutonia quartz monzonite, and Quaternary basalt flows and alluvium. This mineral survey included an examination of two volcanic cinder mines, five lode prospects, two volcanic cinder prospects, and reconnaissance sampling in and near the WSA. The seven prospects are in the WSA; the two volcanic cinder mines are adjacent. No mines are in the WSA. In 1981, there were 61 placer and 3 lode mining claims in the WSA. Sample results from two prospects within the WSA contained significant gold and silver values; however, the mineralized rock is of limited extent and no resources were apparent. Alluvial samples taken throughout the WSA contained only traces of gold. Two volcanic cinder cones within the WSA contain an estimated 30 million tons of cinders. There are sufficient cinders outside the WSA to satisfy demand in the foreseeable future. Stone, sand, and gravel deposits are not resources because similar material is closer to markets. No evidence of energy minerals or geothermal resources was found.

Jan 1, 1985

By Douglas F. Scott

In 1981 the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral survey of the Pyramid RARE II area (No. 5023) covering 23,500 acres (9,500 ha) of E1 Dorado National Forest and 7,900 acres (3,200 ha) of the Lake Tahoe Basin Management Unit (fig. 1). The Bureau of Mines investigation did not reveal mineral deposits in the area. Samples taken from silicified and limonite-stained metasedimentary rocks and aplite dikes were void of precious or base metals or uranium. Placer samples from stream gravels contained no gold values. Molybdenite occurs in quartz stringers within quartz monzonite near Grass Lake, adjacent to the area; no extension; were found in the area.

Jan 1, 1982

By Richard L. Rains

In 1984 and 1985, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied part of the 162,887-acre Mormon Mountains Wilderness Study Area (NV-050-161) in order to evaluate its identified mineral resources. The study area is located in Lincoln County, NV, about 60 miles northeast of Las Vegas. The study area had no mines or mining claims in 1985, and no mineral resources were identified within the study area, or at the Whitmore mine or Iron Blossom prospect near the study area. The alluvial fans around the southern boundary are staked with about 450 placer claims. Chemical analyses of samples indicate that some limestone in the study area is suitable for manufacturing cement or for agricultural purposes but the limestone is distant from markets and therefore not economic in the foreseeable future. The study area is blanketed with oil and gas leases, but no known productive horizons were identified.

Jan 1, 1986

By Donald O. Capstick

A mineral survey of the 520-acre Quigg West Wilderness Study Area (MT-074-155) was conducted by the U.S. Bureau of Mines in 1986 at the request of the U.S. Bureau of Land Management in order to evaluate its identified mineral resources. The Wilderness Study Area is in Granite County in western Montana about 16 miles northwest of Phillipsburg and 27 mi les northeast of Hamilton, MT. Stony Mountain, a study area on lands administered by the U.S. Forest Service, is about 1 mile to the south-southwest and was studied concurrently. No mineral resources were identified in the Quigg West Wilderness Study Area, but high grade gold assays, as much as 1.24 ounce gold per ton, were obtained at the one prospect found. Samples from four workings contained significant gold; minor silver, molybdenum, and copper were also present. The prospect containing the narrow and discontinuous gold-bearing quartz vein straddles the south boundary of the Wilderness Study Area. The shear zone containing the vein projects toward the old Crescent mine, about 4.5 miles to the south, which shows a similar geologic structure.

Jan 1, 1987

By Francis E. Federspiel

Bureau of Mines personnel examined mines, prospects, and mineralized areas to determine the mineral resource potential of the Log Cabin Saddlebag, Hall Natural Area, Horse Meadow, and Tioga Lake RARE II areas in Mono County, California. These areas, along the east slope of the Sierra Nevada, are underlain by Paleozoic metasedimentary and metavolcanic rocks of the Log Cabin Mine and Saddlebag Lake roof pendants. The roof pendants are in Cretaceous granitic rocks. Pleistocene volcanic flows cap some of the older rocks, and glacial till and outwash locally cover the bedrock. The region was eroded by alpine glaciers. Four parts of the Log Cabin Saddlebag area have moderate gold and silver resource potential. Moderate potential for gold and silver resources was identified in one part of the Hall Natural Area and low potential for tungsten and molybdenum in two other parts (fig. 1).

Jan 1, 1982

By Harry W. Campbell

A Bureau of Mines investigation identified no mineral deposits in the Lost Creek RARE II area. Sand and gravel has been mined from alluvial flood plain deposits just outside the RARE II boundary. An oil and gas lease application which includes the eastern portion of the RARE II area is pending. Abundant basalt in the area can be crushed and used as aggregate; but it could not compete with similar deposits in more favorable locations, or with cheaper substitutes such as volcanic cinders or sand and gravel which are available outside the study area closer to major markets. No indication of coal or geothermal energy resources was found. INTRODUCTION Location and Access The Lost Creek RARE II area encompasses 8,300 acres (3,400 ha) of Lassen National Forest in north-central California, about 20 mi (30 km) north of Lassen Peak. The closest city is Redding, California, 50 air mi (80 km) southwest. Peripheral access is provided by State Highway 89 passing near the western RARE II boundary (fig. 1). The Pacific Crest Trail traverses the western margin of Hat Creek Rim adjacent to the eastern boundary of the area.

Jan 1, 1983

Between 1985-1986, the Bureau of Mines reviewed the mining history and minerals information for areas in and near the San Isabel National Forest to appraise the mineral resources present and determine the types of deposits, and their location in the Forest, that could be mined economically if sufficient demand and metal prices existed. The two major metallic deposit-types that are of national mineral resource significance within the Forest are stockwork- molybdenum (with tungsten and tin) and carbonate-replacement zinc-lead-silver deposits. Historically, small gold placers, gold-quartz veins, silver-quartz veins, skarn iron and copper deposits, volcanogenic copper-zinc-precious metal deposits, and base- and precious-metal veins have been mined. Barite, carbonate rocks, gypsum, other non-metallic deposits, and pegmatites, have also been mined. Sand and gravel, present in large volumes, occurs along and has been mined outside the Forest along the upper Arkansas River valley. Turquoise and gemstones are present in small amounts and are of interest to collectors and jewelers. Geologically, sediment-hosted uranium and copper are present in small occurrences but no resources have been identified. Geothermal resources are related to the Rio Grande rift which parallels the central part of the Forest. Four hot spring areas are present - two of these are within the Forest. Because of the low power requirements of the region, and the presence of other generating facilities, these geothermal resources have had only limited local use. Evaluation of mine models that may be found in the region show that base-metal deposits require a high precious-metal component to be economic. Although molybdenum can be produced at economically competitive prices, there is little demand for the product. Capital costs to start new molybdenum mines would be very high and it is not likely that new mines will be put into production in the near future.

Jan 1, 1989

By Edward L. McHugh

Mineral resources in the Silver Creek study area of the Nez Perce National Forest. Idaho, were investigated during the summer Of 1989. The study area includes the 36,100-acre Silver Creek-Pilot Knob RARE II area (No. 1-849) on the north side of the South Fork Clearwater River, about 11 miles west of Elk City, 10. Mines in and near the study area in the Tenmile and Newsome mining districts produced about 100.000 02 of gold, mostly from placers. Gold production had an historic value estimated at 52 million, equivalent to nearly $40 million at today's prices. Lode mines produced about 19,000 oz of gold, along with smaller amounts of silver, copper, lead, and zinc. Of 34 mines and prospects examined, ten lode properties are considered to be significant by virtue of their past development or production and the presence of possibly ore-grade mineralization. There are no identified mineral resources in the study area; however, samples that contained gold and anomalous arsenic delineate a three-mile-long area from the Sentinel mine, north to the Blue Quartz prospect where exploration might disclose resources. One mining company is conducting geophysical studies and drilling within the delineated area. In addition, six placer sites may contain enough gold to be of possible interest for future exploration and development.

Jan 1, 1991

By Thomas J. Peters

The U.S. Bureau of Mines studied the 3,500-acre Winegar Hole study area, Idaho, a legislatively proposed (101st U.s. Congress) addition to the Winegar Hole Wilderness, Wyo.; it adjoins the western boundary of the Wilderness at the Idaho-Wyoming border, about 15 m; east of Ashton, Idaho. The study was part of an Idaho Land Assessment Program to provide minerals information for land-use decisions, and ensure domestic mineral supplies. The study area is an east-west elongated, wooded plateau south of Falls River. Although the area is covered with surficial glacial deposits, it is probably underlain by volcanic flows; light-colored and mafic flow rock were noted in sparse outcrop. No mines, prospects, mineralized areas, or mineral resources were found in the study area during a literature and field search. The only nearby prospects include geothermal and rock aggregate (volcanic cinder) sites, and several placer claims. Although the Winegar Hole study area lies within a region of potential geothermal resources, no evidence of geothermal activity was observed. Rock in the area does not split into flat slabs, which could be useful as dimension stone, and would require crushing to be used 8S aggregate. Alluvium (placer) samples contain less than SO.01 per cubic yard gold (at a $350 per oz price); alluvial deposits are too small to contain gold resources.

Jan 1, 1992

By Michael S. Miller

The U.S. Bureau of Mines (USBM) conducted mineral investigations in the 1,227,000-acre Emigrant Trail study area of Nevada during 1992. During the USBM investigation of 25 areas of development interest, 190 mineral localities were identified and 260 rock and 50 alluvial samples were taken. At least 0.5 million troy ounces of gold, 2.3 million troy ounces of silver, 3.3 million pounds of copper, 10.9 million pounds of lead, 2.4 million pounds of zinc, 500 tons of alunite, 40,000 tons of sulfur, 9,000 pounds of mercury, and 21,000 pounds of tin have been mined from the area and vicinity. Adjacent to the study area, gold is being mined at large, open-pit gold mines, the Hog Ranch and Hycroft Resources, Inc., Sulphur mines, and new production is planned at the Rosebud LAC/Equinox. Hog Ranch mine is nearing depletion, but resources of more than 0.5 million troy ounces of gold and about 5 million ounces of silver are estimated for the Rosebud LAC/Equinox project and more than 0.4 million ounces of gold for the Hycroft Resources, Inc., Sulphur mine. Significant investigations are occurring at SP Ridge and other sites near Scossa and at the Dan claims in the Southern Calico Mountains. Precious opal, placer gold, and geothermal energy resources occur in the study area and vicinity.

Jan 1, 1993

By Len Blackman

The Absaroka-Beartooth Study Area is a tract of approximately 1.4 million acres of National forest land in southern Montana, part of the Greater Yellowstone Area. This study evaluated the mineral potential of four mineral terranes containing undiscovered resources in the area. The geological data is probabilistic, with estimates of the possible number: of deposits and their grades and tonnages. Possible future development scenarios range from no development to many mines, including some very large. As two thirds of the study area is within the Absaroka-Beartooth Wilderness, the future development scenarios reflect the area's mineral potential, not what we expect to see in the foreseeable future. Based on the analysis performed on these four terranes, the most likely future scenario for the study area would include the potential for two medium sized, (predominately) gold, mines, each employing a few hundred workers. There is a small chance, less than 5%, that a large Porphyry Copper or Superior Iron deposit would be discovered and be economically feasible to develop.

Jan 1, 1994

By David A. Benjamin

At the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied prospects, claims, and mineralized sites in a 43,053-acre portion of the 51,262-acre Desatoya Mountains Wilderness Study Area (NV-030-l10) in 1985. The study area, located 50 miles east of Fallon, NV, is underlain by alluvial deposits of Quaternary age and volcanic and volcanic-derived sedimentary rock of Tertiary age. No mines or recent exploration activity were identified within the area studied. The Gold Basin area, located 1/2 mile to the south has produced 982 ounces of gold and 10,086 ounces of silver. The Cold Springs area, located 1/2 mile to the west, has recently been explored for gold-silver. Mineralization at these two areas apparently did not extend into the study area, but future mining at these areas would likely impact it.

Jan 1, 1986

By Lucia Kuizon

The Antimony RARE II area is underlain principally by Mesozoic igneous rocks associated with the Sierra Nevada batholith. The San Andreas fault zone is near the southern boundary. Metallic mineral deposits are associated with the fault zone. These deposits were formed from magmatic solutions, and tend to be along shears and fractures within the country rock. Marble and dolomitic marble deposits occur in Paleozoic roof pendants or inclusions in the Mesozoic intrusive rocks in the area (Troxel and Morton, 1962, p. 52).

Jan 1, 1982

By Alan R. Buehler

A mineral survey of the 20,792-acre Sand Butte WSA (Wilderness study Area), ID-57-8, was conducted by U.S. Bureau of Mines personnel in 1985, at the request of the Bureau of Land Management. The WSA is in Lincoln County, south-central Idaho, about 15 miles south-southeast of Carey. There are no mines, prospects, or claims within the WSA. Basaltic lava is the only rock type exposed within the WSA. The only mineral resource is a few tons of a platy variety of lava (slab pahoehoe) which is suitable for use as decorative stone. Similar slab pahoehoe, produced from other lava fields in southern Idaho, retails for approximately $125/ton. The deposit in the WSA is too small to be mined commercially but may have value to consumers who gather their own decorative stone. INTRODUCTION A mineral survey of the Sand Butte WSA (Wilderness Study Area) 1/ was conducted in June 1985 by the USBM (U.S. Bureau of Mines) and the USGS (U.S. Geological Survey) at the request of the BLM (U.S. Bureau of Land Management). The USBM examines individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will he used to help determine the suitability of the WSA for inclusion into the National Wilderness Preservation System. The immediate goal of this and other USBM mineral surveys is to provide data to the President, Congress, government agencies, and the public for land-use decisions. The long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986