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By Lars Osen

This investigation was undertaken to contribute to the understanding of underground pull tests by conducting laboratory tests under closely controlled conditions. Steel bolts, instrumented with electrical resistance strain gages, were anchored in an aluminum block, a granite block, and a steel sleeve, and were subjected to pull tests. The bearing plates used were either flat7 dished, or embossed. In pull testing a bolt that is prestressed, there is a range of loading during which bolt load is greater than the jack-applied load, This study showed that preload, the size, shape, and type of bearing plate; and the geometry of the system determine the point at which bolt load and applied load become equal. The effects on bolt load of both a theoretical solution and actual pull tests were analogous and led to similar results.

Jan 1, 1965

"IntroductionThe combined library facilities of the five universities in the Generic Technology Center for Respirable Dust, The Pennsylvania State University, West Virginia University, University of Minnesota, Massachusetts Institute of Technology, and Michigan Technological University, represent one of the most extensive and comprehensive collections of information on respirable dust research which is available in the United States. The Center encompasses two major medical schools, the Milton S. Hershey Medical Center at The Pennsylvania State University and .West Virginia University Hospital at West Virginia University, and includes national and international experts from such diverse disciplines as geology, geomechanics, mining engineering, mineral processing, electrical engineering, industrial engineering, mechanical engineering, material science, physics and several areas of medicine. In order to maximize achievements in research and facilitate early results application in the private industry, university, government and public sectors, a geographically dispersed Reference Center on Respirable Dust has been established at each of the affiliated universities. This network serves to encourage unity between the universities in the Center and coordination and communication with other entities who benefit from their research.Description of the Reference CenterIn this light, the goal of the Reference Center network is to identify at what location Information is available and to provide a means for others to access this information. It is especially necessary to have both ease of input and maximum retrieval capabilities available to all the research personnel in the Reference Center. At the same time, the service provided to the inquiring public must be complete and cost-effective. The Center's approach to realizing this goal incorporates advances in computerized and electronic searching of individual library holdings and the networking of major library and commercial search systems.The Reference Center uses the following means to achieve this goal. At each participating university, a hard copy collection ls maintained of the current respirable dust research in progress by that institution's personnel. Also, available. at each university ls a review of their past and present research on respirable dust. At each participating university a hard copy collection of annual status reports and of all publications produced by Center personnel for symposiums, national and international conferences ls maintained. A key word computer search capability ls available to participating universities. This computer search, by title, author and location, allows researchers to determine at which facility information is available, thus avoiding the tremendous expense and effort of housing all the information on respirable dust research under one roof. The Reference Center has access, through The Pennsylvania State University Libraries system and the libraries of other institutions, to a large number of data bases such as MEDLINE at the National Library of Medicine,"

Aug 31, 1989

By A. T. Iannacchione

Roof-rock instability in advancing sections of underground coal mines is a major contributing factor to accidents resulting in fatalities and injuries. Such roof-rock conditions can also result in loss of production due to additional cleanup time and increased amounts of reject material. The Bureau of Mines is investigating fundamental geologic factors affecting coal mine roof-rock instability in order to develop techniques to predict zones of potential unstable roof-rock. Two distinct directional trends of unstable shale roof-rock in a mine working the Upper Kittanning Coalbed are delineated: one trend is associated with the sandstone-shale transition zone, the other with a fault system. The unstable shale roof-rock associated with the transition zone, a consequence of differential compaction, is comprised of slickensided roof-rock. Whereas, the unstable shale roof-rock associated with the fault system, a consequence of structural deformation of the strata, is comprised of fault planes. These faults, small in comparison to the sandstone-shale transition zone, are difficult to delineate with a standard drilling program. Trends of the transition zone associated with the sedimentary facies change are projected into unmined portions of the coalbed with the aid of exploration core data.

Jan 1, 1981

By Robert N. Roby

"The Moffet-Johnston property was investigated by the Bureau of Mines with the object of determining the presence of ore reserves that might be utilized during the war emergency. Preliminary examination was made during May and Juno 1943, as a result of which the Johnston 'tunnel was cleaned out and repaired, the .mime was surveyed, and a small program of exploration was undertaken. This report describes the work performed and presents the data obtained.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts prelimi¬nary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs benefication tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.The chemical and spectrographic analyses were made at Reno, Nov., under the direction of A. C. Rico, acting engineer in charge, Rare and Precious Metals Experiment Station, Bureau of Mines. The ore-dressing tests were under the direction of Rollien R. Wells, metallurgist, at the Salt Lake City laboratories of the Bureau of Mines.The author acknowledges the cooperation and assistance of the lessee of the property, H.R. Hakes, who furnished nine reports and other information.The Moffet-Johnston property is in secs. 2 and 3, T. 3 S., R. 5 W., in the Tidal Wave mining district of Madison County, Montana.The portal of the Johnston adit is near the mouth of Bear Gulch, 9 miles northeast of Twin Bridges, Mont. It is reached by an improved dirt road that serves mining properties farther up Bear Gulch. The Moffet mine and the Mountain View shaft are now accessible from the Bear Gulch road over an access road recently completed by the U. S. Grazing Service. The Grazing Service road has also been supplemented by bulldozer trails built by the Bureau of Mines.An electric-power line extends from the Montana Power Co's substation at Twin Bridges to mines at the head of Bear Gulch and passes within 200 feet of the Johnston portal.The claims of the Moffet-Johnston property were located about 1900. A report by H. V. Winchel, consulting geologist, in 1904 indicates that most of the development on the Johnston adit was completed by that date. At the time of the Winchel report, the Moffet workings had just penetrated the first ore shoot (fig. 4)."

Sep 1, 1946

By Kenneth M. Maas

The Bureau of Mines inventoried the land availability for mineral exploration and development in northern Alaska and compared this land with known mineral terranes and mineral deposits, to quantify the potential for favorable location of mining claims for metalliferous mineral deposits. This report includes thirty-three 1:500,000-scale maps that depict land availability, and the accompanying text and tables relate availability acreage to areas of favorable mineral terranes. Three categories of land availability and ownership are identified, along with 12 subcategories of land status. Available land comprises approximately 14.5 million acres or 16% of the 90.3-million-acre study area; land available with restrictions accounts for 7.5 million acres or 8%; and unavailable land encompasses 68.3 million acres or 76%. Mineral terranes underlie 37.8 million acres or 42% of the study area; 5.3 million acres or 14% are available for mineral location, 2.8 million acres or 7% are available with restrictions, and 29.7 million acres or 79% are unavailable. There are 500 known mineral deposits or occurrences within the study area. This includes 271 lode deposits, of which 171 lie within a recognized mineral terrane and 55 are on available land. The remaining 229 are placer deposits.

Jan 1, 1987

By Paul E. Bennett, James S. Browning, Thomas L. McVay

Continuous 1.0- to 1.5 - ton - per - hour pilot plant flotation tests were made to determine the technical and economic feasibility of recovering beryl from flotation tailing being produced at the spodumene concentrator of the Foote Mineral Company , Kings Mountain , N.C. Best results were obtained when using an acid circuit and amine - type cationic reagents to float a bulk beryl - feldspar concentrate and then selectively floating the beryl away from the feldspar , using a petroleum sulfonate collector . About 77 percent of the beryllium in the pilot plant feed was recovered in a concentrate containing 6.42 percent BeO . The capital cost of an integrated flotation plant capable of treating 500 dry tons of spodumene mill tailing per day for recovery of beryl and feldspar is estimated at $ 210,000 . Indicated direct operating costs for the plant were $ 1.52 per ton of dry spodumene flotation tailing treated . This approximated the value of beryl recovered , but potential profits of about the same magnitude lie in concurrent recovery of marketable spodumene and feldspar byproducts .

Jan 1, 1964

By Brian G. White

The Coeur d'Alene Mining District of northern Idaho is remarkable for its number of large ore bodies and for the amount of its historical production of lead, zinc and silver (Fig. 1). Since veins were first discovered in 1884, more than 127 Mt (140 million st) of ore have been produced from narrow, high-grade veins. Mining continues at the Lucky Friday, Galena and Sunshine mines (Fig. 2). All have been in production for decades. At these mines, more efficient mining and exploration techniques have reduced costs while adding significant new reserves. Even the old Bunker Hill Mine, where ore was first found in 1875, continues operation on a limited basis, partly involving production of world-class pyromorphite specimens. Until recently, the Coeur Mine was also a profitable silver producer. Other large producers have included the Star-Morning, Hecla, Page, Standard-Mammoth, Hercules and Gold Hunter mines (Fig. 2). The first deposits were discovered by prospectors who spilled over from the Murray gold mining district, 24 km (15 miles) to the north. The Bunker Hill Mine was founded the year after the first veins were discovered. Bunker Hill has now operated for more than 100 years. Production includes 2.3 Mt (2.6 million st) of lead, 1.1 Mt (1.2 million st) of zinc and 4.1 kt (132 million oz) of silver. Total district production through 1996 (Springer, 1997) amounted to 7.3 Mt (8.1 million st) of lead, 3 Mt (3.3 million st) of zinc, and 34.5 kt (1.109 billion oz) of silver. This record establishes the district as the largest recorded producer of silver in the world, while also yielding major quantities of lead and zinc. Only Potosi, Bolivia, may have produced more silver, although records are unclear. Despite the district's longevity, historic production and current activity, the published literature on the district lags behind with regard to recent concepts of district geology. The most recent comprehensive US Geological Survey (USGS) bulletins (Hobbs et al., 1965; Fryklund, 1964) are dated. Much research in the last half century has been short-lived or geographically restricted because the district is large and its geology is complex - and even this research tends to remain unpublished. Thus, it has been difficult for in- [ ]

By X. Chi, J. W. Griffith, C. L. Schengrund, J. Sabol

"Experiments were carried out to determine the long-term effect of instillation of 500 mg of generic bituminous, anthracite, quartz, or titanium dioxide (Ti02) dust on the composition of pulmonary surfactant. Dust was instilled in the caudal lobe of the right lungs of female pigtailed macaque monkeys (Macaca nemestrina). The composition of surfactant isolated from cell-free bronchoalveolar lavage (CF-BAL) samples obtained from right lungs (dust exposed) at various times over the following year was compared with that of surfactant isolated from CF-BAL from left lungs (dust free) . Little change was seen in the amount of surfactant-associated lipid phosphorus as a result of exposure to dust. Exposure to quartz, anthracite, or Ti02 dust induced a significant increase in the total amount of protein in the surfactant-enriched fraction. The relative amount of specific proteins was also altered: surfactant-associated protein A decreased, and the amount of the heavy and light chains of immunoglobulin molecules (identified by NHiterminal amino acid sequence analysis) increased. These changes were visible more than a year after instillation of quartz and at least 3 months after instillation of anthracite dust. Despite variation in the responses of the individual animals, the changes observed might serve as an indicator of the severity of the effect of exposure of the lung to mineral dust and/or to pathogens. IntroductionSurfactant is essential for normal pulmonary function and gas exchange. It functions to reduce surface tension and may help to prevent pulmonary edema [19] and to protect against infection [13]. The importance of surfactant to normal Jung function is illustrated by the fact that neonates lacking appropriate surfactant undergo respiratory distress and do not survive without clinical support."

Dec 1, 1996

By W. M. Mahan

This report describes work carried out by the Federal Bureau of Mines in cooperation with the General Services Administration (GSA). Tests on nickel oxide reduction were conducted at the Pyrometallurgical Laboratory at Pitts-burgh and Bruceton, Pa., and at a rented plant at Canonsburg, Pa. Nickel oxide was reduced to sponge nickel, which was then melted to produce specification-grade nickel ingots containing a minimum of 98.50 percent nickel plus cobalt and a maximum of 1.00 percent cobalt. One purpose of this study was to determine if specification-grade nickel could be made from nickel oxide produced at the United States-Government-owned plant at Nicaro, Cuba, in pilot-plant scale operations involving direct reduction and melting processes. A second and equally important purpose was to obtain cost data on the pilot-plant operation to estimate the cost of producing ingot nickel at an annual rate of 12 million pounds. Laboratory tests verified that nickel oxide, in saggers and in the presence of anthracite fines and dolomite in the ratio of approximately 20:5:1, could be converted to sponge nickel when heated to approximately 1,900° F. for about 2 to 4 hours, depending on the size and density of the oxide charge. The tests also determined the type of saggers suitable for pilot-plant operations.

Jan 1, 1959

By R. W. Geehan

The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. Bureau engineers made a preliminary examination of the Morefield mine early in 1943 and recommended investigation by trenching and diamond drilling, The Bureau of Mines conducted work from August to December of 1943, which indicated that the Morefield mine was a favorable location for an experimental mining program. The Bureau of Mines carried on such a program from September 1947 to March 1949. The property investigated is 30 miles southwest of Richmond in Amelia County, Va. (fig. 1). During World War II mica and beryl were shipped from the Morefield mine, but after the high prices and premiums paid during the war years were not available the mine was closed.

Jan 1, 1953

By Robert F. Pettit

This paper on methods and costs of mining and milling iron ore at the Iron Mountain mine of Ozark Ore Co., St, Francois County, Mo., is one of a series of Bureau of Mines reports on methods, practices, and costs of mining and milling throughout the United States. The Iron Mountain operation is notable for its successful transition from open-pit to underground mining, for use underground of large earth-moving equipment, and for development of a multilevel room-and-pillar mining method. Milling methods also have undergone transitions - from hand sorting and log washing in the early days to gravity concentration. Milling ultimately may include flotation to recover additional iron from products now discarded as tailing,

Jan 1, 1957

By J. M. Riley

The Bureau of Mines investigated a promising new technology for recovering A1203 from alunite to support the Bureau's alumina miniplant project. Results are presented for a study of the technical feasibility of treating alunite crushing and grinding reject fines for recovery of A1203. Alunite pellets having sufficient strength and resistance to degradation were produced by combining fines and coarse alunite with a KOH binder. The best pellets were prepared, in a laboratory pelletizer, by adding 1 pct KOH as a 5-pct solution to a mixture of 40 pct alunite dust (98 pct minus 65 mesh) and 60 pct coarse alunite (minus 20 plus 65 mesh). Calcines suitable for K2SO4 and A1203 recovery were produced by reducing dehydrated alunite pellets with sulfur in a laboratory shaft furnace for 4 h at 600° C, followed by air oxidation of the reduced calcine for 1 h at 600° C. This report presents design calculations, schematic diagrams, and discussions of the essential features of a proposed process research unit (PRU)--a continuous, 6-lb/h alunite shaft furnace--for studying the process.

Jan 1, 1983

By Gary A. Kingston

This examination of Pacific Northwest (Idaho, Montana, Oregon, and Washington) ferrous scrap-industry operations, principally those in Oregon and Washington, points out factors influencing the supply and consumption of scrap materials, such as the complete dependence of steel ingot producers in these States on scrap as a metal raw material and the sizable quantity of scrap exported from Seattle and Portland to Japan. The pattern of the industry is presented as a movement of materials from their diverse sources to the consuming market. The geographic locations of the consuming industries in relation to the areas generating scrap materials and the movement pattern of the supply from source to destination strongly influences the cost of the commodity. The best measure of the scrap supply available in an area is experience in terms of how much scrap was withdrawn at a given price. Scrap availability is not finite, because the return of materials as scrap is secular and influenced by constantly varying market conditions. Steel ingot producers use 75 percent of the approximate 500,000 tons of scrap consumed in Oregon and Washington; steel foundries take 15 percent of the total; and iron foundries, ferroalloy plants, and other miscellaneous consumers utilize the remainder. Also, from 1955 to 1960 an average of about 200,000 tons has been exported annually from Oregon and Washington. The foreign exports are supplemented by lesser shipments to other steel producing States, principally in the western United States. From 1955 to 1960 the preferred and higher value heavy melting scrap grades accounted for about 60 percent of total withdrawals which varied between 600,000 and 950,000 tons annually. Total crap withdrawals from Oregon and Washington are projected to 1.8 million tons by 1985, 60 percent (1.1 million tons) of which will be heavy melting grades. No. 1 heavy melting scrap is most attractive to scrap consumers at $35 per ton or less. Price-supply relationships compared with projected scrap requirements indicate future prices possibly over $35 per ton. High prices over a long period could motivate the Pacific Northwest scrap consumers to produce steel from iron ore. However, technologic changes taking place at integrated steel plants could reduce scrap withdrawals from the Pacific Northwest, which might keep the scrap price sufficiently attractive to obviate production of competitive iron products by the Pacific Northwest scrap consumers.

Jan 1, 1964

By George A. Morgan

The production and processing of crude petroleum and natural gas are the dominant economic sectors of the Middle East. The 15 countries that constitute the region accounted for 28% of world crude petroleum output, 17.2% of world natural gas plant liquid production, and 5.3% of world dry natural gas production. Only Cyprus and Lebanon were not crude petroleum producers. About 66% of total world crude petroleum reserves and 31 % of total world natural gas reserves are in the Middle East. Transportation and port facilities in the region are geared to expediting efficient and rapid shipment of these materials. Export sales of these fuels provide funding for further diversification of the mineral industry. Additional development of downstream facilities for producing energy-intensive metals such as aluminum and byproducts of the fuels such as petrochemicals and fertilizers can be expected. Earnings from the industry are also channeled by several Governments in the region to mineral industry projects in Africa and elsewhere. Several countries in the region own major petroleum refineries and distribution facilities worldwide. Petroleum prices rose overall during the year owing to the invasion by Iraq of Kuwait in August 1990. Output from both countries, the fourth and fifth largest producers, respectively, in the Middle East, was negatively affected by the war. Kuwaiti crude oil wells and pipeline facilities suffered extensive war damage while exports of petroleum and petroleum refinery products by Iraq ceased owing to a U.N. embargo. The embargo also impacted Jordan, an exporter of phosphate and potash. Shipments of crude petroleum by pipeline from Iraq through Saudi Arabia and Turkey and by vessel through the Persian Gulf were terminated. However, the loss in production from Iraq and Kuwait was more than made up by accelerated output from other Middle East and world producers. Saudi Arabia, in particular, with its excess production capacity, accounted for the largest portion of the increase.

Jan 1, 1992

By L. G. Trudell, J. W. Smith, K. E. Stanfield

Representation of actual oil yields from sections of the Green River formation oil shales by two types of drill - cutting samples was evaluated . Average oil yields of single sets of mud cuttings from hydraulic rotary drilling in Colorado and gas cuttings from pneumatic rotary drilling in Utah were compared statistically with yields of core samples taken from adjacent holes . Oil yields from gas cuttings were identical to oil yields of core samples . Mud cuttings appeared to represent a section of the formation conservatively , the deficiencies increasing with increasing richness of sample . Because a large amount of the oil - yield data currently available for the Green River formation is based on mud- cutting samples , development of a valid correction method by additional testing is needed .

Jan 1, 1963

By O. S. North

As recently as the late 1920's there Were few indications that a 15-million-dollar-a-year industry would ever grow out of the mineralogic curiosity vermiculite. Today, it is an important industrial commodity, used primarily as an insulating material and lightweight aggregate, but with a wide range of other applications. The quantity of crude vermiculite produced and used in the United States increased 14-fold in the 17 years between 1935 and 1951. The vermiculite minerals are of secondary origin, formed by hydrothermal alteration of an ultrabasic igneous rock, generally pyroxenite, or by alteration of phlogopite or biotite mica or possibly other similar minerals. According to different authorities, vermiculite may originate either by direct hydrothermel means, by the weathering of biotite or phlogopite, or by a combination of these two agencies. Vermiculites frequently occur at or near the contacts of an acid intrusive rock, especially a pegmatite dike, with a basic or ultrabasic country rock.

Jan 1, 1953

By Charles L. Kimbell

Comprehensive world mineral industry investment data do not exist, but limited material published on aggregates of in vestment in some elements of the world mineral industry suggest a continued up-turn in the investment level, at least in market economy countries in 1989. Steel industry investments in Organization for Economic Cooperation and Development (OECD) countries are not yet available for 1989 but, as shown in table 6, increased by 22.1% in 1988, after showing a decrease of 5.2% (revised) in 1987. The pattern of investment ups and downs varied during 1988 within country blocs and economic alliances showing no particular trends. Investment in the steel industry by the United States increased by 58.3% between 1987 and 1988 and was 1 1.9% higher than the previous highest amount invested during the 1984-88 period but was still 41.5% less than the amount invested in 1983. Investment in the steel industries of the European Coal and Steel Community (ECSC) dropped again in 1988 from the revised amount for 1987, which became the first drop after several years of steady growth in what became the expanded ECSC in 1986. This drop in 1988 was the result of lower investments by Denmark, France, the Federal Republic of Germany, Ireland, Italy, Luxembourg, the Nether- lands, and Spain, investments grew or remained level in Belgium, Portugal, and the United Kingdom in 1987 and 1988. A decrease in investment in the Canadian (-26.6%) steel industry was offset by in- creases registered by the members of the European Free Trade Association (EFTA) of 31.7%, by Japan of 19.8% by Turkey of 22.4%, and a slight increase by the nations of Latin America. If data for the world steel industry as a whole, including those of the centrally planned economy countries, were available, the same pattern presumably would be shown as that reported; that is, it would remain fairly stable, with increases in some countries being offset by decreases in others. However, the lack of comprehensive information on the centrally planned economy countries makes it impossible to determine whether the overall trend was up or down despite recorded increases or decreases in production of the materials involved. Preliminary data show that investment levels in industries dealing with the production and/ or processing of mineral commodities for

Jan 1, 1992

By R. V. Lundquist

This report describes results of tests on the desilication of solutions resulting from the leaching of lime-soda sinters. Desilication was accomplished by heating the solutions in an autoclave. A liquor relatively free of silica was obtained after 30 minutes of heating at 200 p.s.i.g. in the presence of lime. The addition of lime improved desilication, but the rate and efficiency of desilication was effected by the quality of lime used. The optimum quantity of lime for effective desilication was about 6 grams per liter. A lesser quantity gave poorer desilication, and a greater quantity increased the alumina loss without improving desilication. The alumina loss was approximately proportional to the lime added. A complex structure, called artificial noselite in this report, was the only silica bearing compound detected in the desilication precipitate. Other compounds present were Ca(OH)2 (calcium hydroxide), CaCO3 (calcium carbonate), and Ca [A1(OH)6]2 (hydrated tricalcium aluminate). Sodium carbonate in the leach liquor retarded the formation of the calcium aluminate; hence it decreased the alumina lost to the precipitate. The extraction of alumina from aluminum silicate materials by the limestone soda-sinter process has been investigated by the Bureau of Mines for many years. The process consists of the following major operations: Blending the aluminum silicate with limestone and soda ash in such proportions that dicalcium silicate and sodium aluminate are formed on sintering; leaching the sinter in a carbonated caustic solution to extract the soluble alumina; purifying the leach liquor by the precipitation of soluble silica (this precipitate is designated desilication precipitate in this paper); precipitating alumina trihydrate from the purified liquors by carbonating with carbon dioxide gas; and calcining the trihydrate to alumina. Commercial grades of

Jan 1, 1962

By John D. Spencer

Projects aimed at achieving the least disturbance to the Nation's air, water, and land resources in the mining and utilization of coal continued to be a feature of the Bureau of Mines coal program. This reflects the current concern about damage inflicted on the environment by our growing and increasingly affluent society. Mine Health and Safety research, along with investigations related to all other aspects of coal extraction and use, also continued to be implemented and expanded.

Jan 1, 1970

By John T. Neubert

Between 1988 and 1990, the U.S. Bureau of Mines studied the mineral resources of San Juan National Forest to appraise and determine types and locations of deposits that could be mined economically now and in the foreseeable future. The study included a comprehensive field examination and literature search. Substantial amounts of lead, zinc, copper, gold, and silver have been mined from within the Forest in the La Plata, Rico, Silverton, and Dunton areas. At least one buried 200 million ton stockwork molybdenum deposit occurs in the Rico area. Similar size porphyry copper deposits occur at the surface and about 1,700 feet below the surface in the Bedrock Creek area of the La Plata district. Numerous smaller base-and precious-metal and uranium deposits have been prospected and mined throughout the Forest. Coal, oil, and gas have been or are currently being produced in the western and southern parts of the Forest. Carbon dioxide occurs in the western part of the Forest. Strategic elements occurring within the Forest include platinum, palladium, cadmium, gallium, indium, bismuth, and tellurium; however none of these elements is economically recoverable at present. Several geothermal areas are scattered across the eastern two-thirds of the Forest. Industrial minerals within the Forest include sand and gravel, limestone, and decorative stone.

Jan 1, 1992