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By G. R. Smith

Critical and strategic metals are often present in small quantities in low-grade domestic ores. When these ores are leached, the resulting solution usually contains the metals in very dilute quantities. Selective electrowinning from dilute electrolytes was investigated by the Bureau of Mines. A metal deposit containing 84 pct nickel was electrowon from the leach solution of a complex domestic ore bulk flotation concentrate originally containing approximately 2 wt-pct nickel. Key to achieving accelerated deposition rates, in the case of dilute solutions, is the rapid movement of the electrolyte through the electrowinning cell. Pure, synthetic nickel electrolytes were used to establish deposition parameters, and to optimize electrolyte velocity or mass transfer rates. Hydrodynamic and electrodeposition parameters for both the synthetic and leach electrolytes are presented and the experimental research described. Selective electrowinning appears to offer a viable alternative to physical separation methods to obtain separate metal "concentrates" from low-grade ores.

Jan 1, 1983

By Travis Q. Lyday

Mineral production in Fiji, a group of 322 volcanic islands and atolls of Melanesia in the southern Pacific Ocean, continued to be dominated by gold. However, the Fijian mineral sector remained a minor factor as a source of export earnings, Government revenues, and employment, generating only 1% of the gross domestic product (GDP), estimated as $1.2 billion.2 The largest and most important mining operation was the Vatukoula gold mine on the north side of Viti Levu, the main island. The Vatukoula Mine has been in prduction since 1932, producing about 3.8 million troy ounces of gold and 1.3 million troy ounces of silver to date. In April 1983, the large Australian mining firm, Western Mining Corp. (WMC), assumed operation of the mine in a joint venture with Emperor Gold Mining Co. Ltd., which operated the mine previously. The WMC takeover of the mine management was expected to bring in additional capital and technological expertise in order to modernize operations, increasing both efficiency and output. During the year, rate of recovery was only about 75% of the gold contained in the ore and only 40% of the contained silver. Mining at the Vatukoula Mine was done using bath opencut and underground methods, with about 60% of the ore mined attributed to the underground operations.

Jan 1, 1985

By Thomas O. Glover

The mining industry of Cameroon continued to be dominated by crude petroleum. Crude petroleum production has become the most important facet of Cameroon's economic development. Oil production was estimated to be 6.3 million tons in 1983 compared with 5.2 million tons in 1982 and 4.3 million tons in 1981. Over two-thirds of its export income was attributed to crude oil. The country's only refinery, dedicated in 1981, has a production capacity of 2 million tons. Cameroon has become self- sufficient in petroleum products since commissioning the refinery. The oil sector contributed approximately 13.5% to Cameroon's gross domestic product in 1982-83. Oil production was expected to rise from 125,000 barrels per day in 1983 to 156,000 barrels per day in 1985 when output peaks. Cameroon's ultimate recoverable reserves have been calculated at 100 million tons, or 750 million barrels of oil.

Jan 1, 1985

By Joseph J. Wallace

1. The Pocahontas No. 3 and Pocahontas No. 6 ere the two most important beds in Mercer County from the standpoint of present production and recoverable reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated at 188 million short tons as of January l, 1953. Of this total, 80 million short tons are in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1954

By J. M. West

Expanded war in Viet-Nam overshadowed activities in the Far East in 1965, diverting capital and materials from potential regional development projects. Japan with-stood a period of business recession that was particularly felt by its coal mining and iron and steel industries. Toward yearend signs of improvement began to show. Despite the recession with attendant credit restrictions and forced cutbacks in areas of overproduction, Japan's overall industrial output rose nearly 5 percent during the year. Foreign trade, liberalized in 1964, was a strong point in the Japanese economy and took the place of lagging domestic demand. Japan maintained its third place in world production of iron and steel ahead of West Germany and in 1965 was the world's fore-most exporter of iron and steel in primary and semimanufactured forms. Economic setbacks in mainland China caused by its "Great Leap" failures and subsequent withdrawal of Soviet technical assistance were difficulties relegated to the past. However, a newly formed "Red Guard" political group, part of a so-called cultural revolution, was due to cause new disruptions in 1966. Nevertheless, significant gains were claimed in Chinese industry, and the country approached self-sufficiency in petroleum in 1965 by virtue of its Tach'ing oilfield. Restoration of friendly relations was achieved between South Korea and Japan accompanied by Japanese offers of industrial aid and increased trade. Indonesia's economy was deteriorating; the country withdrew from regional development organizations and continued its stubborn confrontation policy against Malaysia throughout 1965. Late in the year after a Communist uprising had been quelled, there was a period of political retrenchme t and it was hoped that economic improvements would follow. Petroleum remained a strong area in Indonesia's varied resources, and its production was increasing. Tin output declined, however, because of operating difficulties.

Jan 1, 1967

By A. J. Rambosek

An evaluation of diamond-bit performance data accumulated from core drilling in quartzite shows that core recovery and physical characteristics of drill bits and diamonds have economic significance. Relatively inexpensive, low-quality, small Congo diamonds will perform as well as, or better than, other diamonds used as drill bart. M-type bits set with oriented Congo diamonds provide those engaged in core drilling with near optimum combination. Various factors that affect bit performance, including size of diamonds, size and type of bits, grade or quality of diamonds, and percentage of core recovered, are evaluated by means of tables, charts, and discussion.

Jan 1, 1958

By Robert Stefanko

The growing demand for energy during the post World War I and World War II periods has prompted underground coal production to increase rapidly. This has been met primarily by mine mechanization, resulting in the development and application of new mining machine types. Correspondingly, the total connected horsepower of each machine as well as the number employed has enlarged rapidly since 1950. (2,3,9,14,16,17) Electrical consumption for each mine has also grown. In the early years of mining electrical applications, only d-c power was utilized underground. Yet, d-c machine limitations were soon realized, and many a-c systems were substituted to permit economic and efficient utilization of a-c distribution and motors. Due to the attractive torque characteristics, ease of distribution and speed control, several traction applications have continued to be powered by d-c motors. The result has been the now prevalent use of mixed a-c/d-c mine power. However, augmented electrical power employment seems to have added to underground coal mining electrical accidents.

Jan 1, 1974

By F. G. Scott

This document is a proposed program plan for mining environmental research to be conducted by the U.S. Bureau of Mines in support of industrial oil shale mining and processing. This program plan is one of three research alternatives being considered by the Bureau, each based on a different level of anticipated funding. This report documents the low funding level program plan.

Jan 1, 1980

By Arnold B. Hubbard

This report describes a method of concentrating the insoluble organic material (kerogen) in a rich Colorado oil shale without any apparent alteration of its original chemical form. The method involved treating finely pulverized shale with dilute acetic acid at room temperature to remove the carbonates, which act as a cementing agent for the shale, and cause the shale particles to partly disintegrate into the organic and inorganic components. The acid-treated shale then was centrifuged in different liquid mediums ranging from 1.4 to 1.15 gravity to effect a mechanical separation. From a Colorado oil shale containing 48.0 percent ash, kerogen concentrates containing 43.3 to 8.7 percent ash were obtained. The carbon:hydrogen ratios of the kerogen in the original shale and the different concentrates were essentially the same. The oil:kerogen ratios calculated from Fischer assays of the above samples were essentially the same, regardless of the organic or inorganic contents. This was also true of the assay water:kerogen ratios of the same samples. These data indicate that no significant change occurred in the kerogen during the concentration process.

Jan 1, 1952

By J. W. Paul

The material that composes the roof in coal mines differs in strength according to variations in its physical nature and characteristics. Some material such as limestone and massive sandstone, (free from slits) and carbonaceous shale or bone, will often remain in place in narrow work without the use of timber or other means of support, but in wide places the use of supports becomes a real necessity. Roof material composed of shale, fire clay or small laminations of sandstone, or shale or sandstone interspersed with laminations of thin coal, presents conditions that call for timber support in both narrow and wide work. However, in narrow work such unstable roof material may be taken down until the strata assume an arch that is self-supporting for overlying firm strata such as a roof coal, a touch weather-resisting, shale, sandstone, or limestone. The proper support of the roof in roadways used for haulage or travel adds to the economy of operation by preventing delays in transportation and increases the safety of those who travel these roadways.

Jan 1, 1930

By R. O. Dannenberg

Exploratory research was conducted to ascertain the feasibility of recovering beryllium from Spor Mountain, Utah, ore by the sodium fluosilicate (Na2SiF6) method used industrially for processing beryl. Na2SiF6 requirements to form water-soluble salts of beryllium were determined for three different samples--two clayey ores containing 0.6 and 1.3 pct BeO, respectively, and a calcareous ore containing 0.6 pct BeO. The ores were sintered with Na2SiF6 at 750° C for 3 hours. About 80 pct of the beryllium was rendered water soluble by sintering the 0.6-pct BeO ores with 30 and 40 lb Na2SiF6 per lb BeO contained in clayey and calcareous ores, respectively. The higher grade 1.3-pct BeO clayey ore required only 20 lb Na2SiF6 per lb BeO to solubilize over 80 pet of the beryllium. As the 0.6-pct BeO clayey ore was possibly the most representative of the deposit as presently delineated, leach liquor prepared from this sample was treated to recover beryllium salts. About 60 pet of the beryllium contained in the ore was recovered as beryllium hydroxide, which then was calcined to yield a 99-pct BeO final product by means of the following operations: (1) Sintering with Na2SiF2, (2) leaching with water, (3) precipitating crude Be(OH)2 by adding NaOH, (4) filtering to separate the hydroxide from the NaF solution, (5) redissolving the crude Be(OH)2 in excess NaOH, (6) filtering to reject caustic-insoluble impurities, and finally (7) boiling the Na2BeO2 filtrate from (8) to precipitate pure Be(OH)2. Reagent consumption was 49 lb Na2SiF6 per lb BeO recovered and 17 lb NaOH per lb BeO.

Jan 1, 1963

By Jerry E. Olson

In 1988, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied additional areas, encompassing 11,303 acres, on the east and west sides of the 20,727-acre Badlands study area (Olson, 1987) in order to evaluate their identified mineral resources. The Badlands study area additions are located in Crook and Deschutes Counties, OR, about 10 and 18 miles east of Bend, OR. No mineral resources were identified. The additional areas studied are underlain by Tertiary-and Quaternary-age basalt flows which are largely covered by a veneer of sand and silt. No mines, prospects, mining claims or mineralized areas occur within or near the Badlands study area additions. Slab lava of marketable grade and quantity was not found in either area. None of the study area is of current interest for geothermal resources, but the eastern study area addition has been leased (1984) for oil and gas.

Jan 1, 1989

By S. B. Levin

The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States and Alaska since 1939. During the fall of 1942, the Bureau of Mines put down nine diamond-drill holes at the Cape Rosier zinc-copper-lead mine in Hancock County, Maine, that aggregated 2,883 feet of bore. These holes supplemented 13 holes, aggregating. 5,501 feet, put down on the property about 2 years earlier by the St. Joseph Lead Co. Veins of mixed sulfides were intersected in 15 of the holes drilled. Beneficiation tests were made on samples of ore obtained from old dumps. Zinc-copper-lead sulfides occur at the Cape Rosier mine as lenses in a zone of altered agglomerate beneath and between a series of diorite sills. The mineralized zone strikes F. 17° E. and dips southeast. Between July 1881 and September 1883 the mine produced about 10,000 tons of ore reported to have contained 20 percent zinc, 2.8 percent copper, and some lead. The crude ore was hand-sorted, and some. 3,000 tons were reported shipped.

Jan 1, 1948

By C. J. Johnson, C. J. Bise

"The occurrence of Coal Worker's Pneumoconiosis (CWP) ·has been potentially linked with several characteristics of coal such as rank, volatility, percent content of ash and non-coal components, quartz content, and the presence of several trace elements. According to the National Research Council, numerous epidemiological Studies: indicate that the incidence of CWP varies significantly with the composition and/or the concentration of the coal mine dust.Although advances in dust suppression techniques have markedly reduced respirable dust levels in underground coal mines, the National Research Council has concluded that chemical characteristics of respirable dust from different coal seams should be studied. With this objective in mind, research has been conducted in underground coal mines located in the eastern and mid-western United States, and in the laboratory to characterize the elemental composition of mining-generated airborne dust and laboratory-generated dust derived from samples taken from these mines. The goal of the research is to determine if a relationship exists between mining-generated and laboratory-generated dust from the ·same mine. Results of this research will be presented. ,"

Jan 1, 1988

By Wilbert J. Huff

The Explosives Division of the United States Bureau of Mines makes certain laboratory and field investigations that deal with explosions, explosives, ignition, and combustion, together with many related problems, such as the cause and prevention of fires, and certain fundamental scientific questions bearing upon the determination of the chemical and physical mechanisms underlying some of the important phenomena encountered. Its work on explosives has been particularly directed toward determination of the chemical and physical characteristics of explosives designed for use in coal mines and in a more limited way to those used in metal mines, tunnels, quarries, and other engineering operations. This testing is handled by two units of the Explosives Division, as follows:

Jan 1, 1937

By John R. McDonnell

The Valle Vidal Unit comprises 100,000 acres In Taos and Colfax: Counties, New Mexico. The unit was donated to the American public In 1982 by the Pennzoll Co. and is administered by the U.S. Department of Agriculture Forest Service as an addition to the Carson National Forest. During 1990-1991, the Bureau of Mines conducted a mineral Investigation of the unit as authorized by an Interagency Agreement (1987) Intended to assist the Forest Service to incorporate mineral resource data In forest plans. The Bureau reviewed literature and records concerning mineral resources and mining activity, and performed a field examination of mines, prospects, and mineral occurrences in and near the Valle Vidal Unit. The La Belle mining district encompasses most of the western part of the Valle Vidal Unit. The district was most active between 1893 and 1902, after the land grant was opened to prospecting and gold discoveries were reported. The discoveries were low grade, and eventually were abandoned. The Bureau's appraisal of the district determined that lode gold occurs primarily in fissure veins in volcanic rocks, and placer gold occurs In weakly cemented sedimentary rocks and alluvial sediments; but at a grade that is currently considered subeconomic. If the price of gold increases in the future, prospecting and exploration in the area may be renewed, but the activity would likely be limited due to "acquired land status" restrictions, which require mineral leasing and prohibit claim location in the Valle Vidal Unit.

Jan 1, 1992

By Thomas M. Barczak

Longwall roof behavior is characterized by strata displacements in both the face-to-waste (horizontal) and roof-to-f1oor (vertical) direc-tions. The roof support structure provides resistance to this motion by translation of these displacements into vertical and horizontal support loading. Observations indicate that the shield reacts with both a vertical and horizontal force to uniaxial convergence (displacement). However, there are different magnitudes depending on whether the displacement is vertical or horizontal. This makes it possible to use supports as monitors of strata activity and loading. The Bureau of Mines examined this behavior using a linear elastic model of the support structure with two degrees of freedom. Vertical and horizontal load reactions were related to associated displacement actions of the strata. This was done by determining the stiffness of the shield under controlled vertical and horizontal displacement motions in the Bureau's mine roof simulator. This report provides example predictions of strata convergence and isolation of horizontal support loading due to vertical roof convergence using the linear elastic shield model. The report also examines efforts to determine strata behavior by direct measurement of support displacement.

Jan 1, 1987

By R. B. Stroud

Bureau of Mines studies of copper-bearing Permian red beds, which extend from north-central Texas through western Oklahoma to southwestern Kansas, indicate heretofore undefined commercial possibilities for low-grade, medium-volume, strip-mining operations. Potential ore bodies are indicated containing 0.5 to 1.5 percent copper in zones 6 to 12 inches thick. Cost analysis studies indicate a commercial operation is feasible for a hypothecated 1,000-ton-per-day ore mining and milling complex where a maximum of 60 feet of overburden can be stripped in mining a seam of shale 12 inches thick containing 1.2 percent copper

Jan 1, 1970

By F. Chase, D. Pappas

Pillar recovery has been associated with nearly one third of roof fall fatalities in underground coal mines during the past decade. Safe pillar recovery requires global stability and local stability. Global stability is addressed primarily through pillar design. The local stability risk factors include cut sequence, the final pillar stump, supplemental supports (timbers vs. Mobile Roof Supports (MRS)), roof bolting, and many others. The National Institute for Occupational Safety and Health (NIOSH) has evaluated each of these factors through field research and analysis of accident statistics. The paper discusses design methods and technologies that have been transferred to the mining community and implemented.

By Gene F. ] [Faufaul

This contract was concerned with the design, development, fabrication and testing of an improved tamper-proof filter cassette assembly for use in the, collection and evaluation of dust particulates, primarily in mining areas. This report presents the design effort, fabrication and tenting of five- prototypre unit$ as well as the design and production of 1000 filter cassettes with sampling heads. This new improved filter cassette has been tested and approved by NIOSH as meeting the requirements specified in the contract.

Jan 1, 1978