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By H. A. Doerner

"Statistics show3 that in 1927 the United States consumed 60 per cent of the world's production of chromite and produced none. The uses of chromium are rapidly expanding, and a dependable supply is essential to our industries. Since the political and commercial control of our supply of chromite is now in foreign hands it is prudent to determine how this nation can best prepare to supply its need for chromium if the imports were cut off or restricted and whether it is now possible and desirable to stimulate production of chromium from domestic deposits. We have only small amounts of chrome ore of high enough grade to meet present trade requirements. Therefore the Bureau of Mines is making a study of methods for beneficiating our low-grade ores.Chromite (Cr203.Fe0), is the only commercial source of chromium. For refractories, a minimum of 40 per cent Cr203 and a low silica content (5 to 8 per cent) is usually specified. In most instances bricks or lumps having a physical structure that will not crack when heated are required. The only way an inferior ore could be adapted to this use world be to concentrate it and develop a satisfactory binder to make bricks out of the concentrates.For making ferrochrome the requirements are a minimum of 45 per cent Cr203 and an iron content not exceeding one-third of the chromic oxide. On some low-grade ores gravity concentration will give a product meeting these requirements; other ores yield concentrates containing too much iron or other impurities to be saleable."

Jun 1, 1930

By Franklin H. Persse

Domestic bismuth supply was projected from production figures for the ores in which it occurs--copper, lead, zinc, and tungsten. Published and unpublished data concerning host ores were examined to determine bismuth reserves and resources, and mine production. Potential recoverable bismuth occurring with reserves and resources of copper, lead, and zinc was estimated to be 36.3 million pounds. A bismuth availability diagram was developed from quantity estimates and ratios of production cost to value for these host ores. Additional recoverable bismuth occurring with domestic tungsten reserves was estimated to be 1.5 million pounds. Domestic byproduct production of bismuth will approximate 1.3 million pounds annually by 1980. This quantity will provide about 37 percent of the 3.5-million-pound estimated requirement for that year. Known world supply of bismuth appears to be sufficient for world demand to the end of this century. The study indicates that bismuth reserves and potential resources in the rest of the world have not been adequately reported.

Jan 1, 1970

By Timothy J. Rohrbacher

This report presents a U.S. Bureau of Mines study that incorporates coal mining factors, coal recovery factors, and economic factors into the definition of an economically recoverable coal resource. The relationship between these factors to the Energy Information Administration's estimate of U.S. coal resources-the "Demonstrated Reserve Base"-is discussed. The Boltsfork 7 1/2-minute quadrangle in eastern Kentucky was selected as the study area. Results indicate that of the original 280.2 M tons of resource in the quadrangle, only 99.8 M tons (35.6%) is recoverable at a mining cost of $25 per ton or less.

Jan 1, 1994

By T. D. Hackett

Multislice mining methods were analyzed by the U.S. Bureau of Mines to determine their application to western United States thick coal seams; ground control, geology, and costs were considered. Multislice mining is used in widely varying seam conditions worldwide, including flat seams too thick to mine in a single pass, pitching thick seams, and seams containing a rock parting. Longwall multislice methods predominate, but room-and-pillar variants also exist. The initial use of the method in western seams is planned at a deep Colorado mine where a rock parting will be used to separate two slices mined by longwall. Ground control and spontaneous combustion are major hazards associated with multislice mining. A well-consolidated upper slice gob can reduce ground control problems and provide a seal against spontaneous combustion. Geologic analysis indicates that the consolidation of the gob depends on the composition of the upper slice roof, the presence of water, and sufficient overburden pressure. A geologically competent intermediate rock parting can also reduce ground control problems and seal against spontaneous combustion. To compete in western coal markets, the cost of multislice mining must be within the range of normal longwall costs. Analysis indicates that multislice operating costs should be within this range, and that multislice mining costs decrease as panel width increases. Relatively wide (600 to 800 ft) panels also provide increased coal recovery.

Jan 1, 1990

Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a three-dimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHA regulated businesses that use materials containing 0.1 or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHA-regulated businesses may choose to do so if they wish to show that they are exempt from the requirements of HCS. Because crystalline silica is an extremely common mineral and the HCS will affect many mineral commodities, it is important then, that there be as clear an understanding as possible of what is and what is not crystalline silica, and where it is found and used, and how it is qualitatively and quantitatively identified. This primer is an attempt to accomplish this in as nontechnical a manner as possible. This primer will examine crystalline silica. Part I will describe, in nonscientific terms, what crystalline silica is and how we come in contact with it. Part" will discuss the regulatory decisions that have created new interest in this ancient and widespread substance and will present a nontechnical overview of the techniques used to measure crystalline silica. Because this primer is meant to be a starting point for anyone interested in learning more about crystalline silica, a list of selected readings and other resources is included. The detailed glossary, which defines many terms that are beyond the scope of this publication, is designed to help the reader move from this presentation to a more technical one, the inevitable next step.

Jan 1, 1992

By W. A. Calhoun

This investigation of low-grade bauxites as potential sources of aluminum by caustic desilication and alumina extraction was undertaken by the Bureau of Mines to develop extractive methods for winning alumina from domestic deposits of low-grade bauxites. This report is the second of a series covering the work by the Bureau of Mines' Rolla, Mo., and Bauxite, Ark., laboratories. The first report published in the Journal of Metals, December 1951,3/ and dealt with kaolin and halloysite. The present investigation is concerned with low-grade bauxites only. The purpose of these investigations is to increase the domestic supply of aluminum ores. With eventual depletion of high-grade deposits, aluminous materials, such as low-grade bauxite, clays, shales, and high-iron laterites, will become our principal domestic sources of aluminum. The development of extractive processes for winning alumina from these low-grade materials is one of the many national security measures undertaken by the Bureau of Mines. A method has-been developed in the laboratory for successfully treating high-silica bauxites from domestic deposits. In this process the bauxite was calcined at 980° C. to form amorphous silica and alumina. The calcine was then leached by percolation with 15-percent sodium hydroxide solution at 940 to 96° C., removing 67 to 77 percent of the silica with a loss of 4.1 to 5.0 percent of the alumina. The sodium hydroxide in the spent liquor used in desilication was 95 percent recoverable, and comparable desilication results were obtained with 100-percent reclaimed liquor, The indicated cost of reagents, for sodium hydroxide and lime used in the desilication and regenera¬tion of spent liquor, was about $4.00 per ton of calcine treated.

Jan 1, 1954

By Arnold C. Love

This report discusses current research by the U.S. Bureau of Mines on the effects of whole-body vibration (WBV) and shock on underground mobile equipment operators. The highlights of a comprehensive literature review of WBV, shock, and seating are presented. Factors discussed include health and physiological effects, comfort, performance, and fatigue. Vibration data were collected from shuttle cars and ramcars at several underground coal mines in Pennsylvania, Ohio, and Illinois. The data were formatted so that they could be used to drive the Bureau's motion platform, and to compare them with ANSI S3-1979, Guide for the Evaluation of Human Exposure to Whole-Body Vibration. Human subject testing in the Bureau's vibration research laboratory evaluated the effects of two different seat angles and of the presence or absence of vibration and of foam padding on heart rate, blood pressure, and subjective discomfort. Only vibration significantly increased heart rate and systolic and mean blood pressures. Vibration and a steel seat had a significant effect on subjective discomfort. The apparatus used for these tests and the experimental procedures are described in detail. Recommendations are made for additional research on the exposure of underground mining machine operators to WBV and shock.

Jan 1, 2010

The Anaconda Copper Company reportedly reached an exclusive agreement with Cook Inlet Region, Inc., to explore 24 million acres in south-central Alaska and to share equally with Cook the proceeds of any mineral discovery. According to an Anaconda geologist, "the company is anticipating, based on geologic testing, that it will find significant deposits of copper, lead, and zinc. There is also evidence of the presence of precious metals such as silver and gold, and also strong evidence of strategic minerals such as chrome, platinum, tin, and nickel." Cook Inlet Region, Inc., is owned by 6,500 Alaskan natives. Chile, which has a growing, free-market economy under President Pinochet, reportedly will no longer require companies to obtain prior governmental approval for the exploration and development of new mines.

Jan 1, 1981

By R. M. Santmyers

The pigments, whose colors are due primarily to iron exides and iron hydroxides, comprise a variety of yellow, brown, red, and sometimes black paint-coloring agents, both natural and artificially prepared. The natural pigments in this group include ocher, umber, sienna, mineral paints, paint rock, and mortar colors. When the natural color or tinting power--either in the raw state or after treatment--is too weak, these pigments may be "forti- fied" or strengthened. Ocher, umber, and sienna, rhile often described as "iron oxide pigments," are also known as "earthy" rigments. Inasmuch as the iron content of these pigments is, in general, somewhat lower than that of other iron oxide pigments, the ochers, umbers, siennes, and other brown earth pigments are not discussed in the present paper. In addition to a discussion of natural or artificial pigments whose color is due to the presence of iron oxide in some form, this paper contains data on mortar colors, which are medium or low grade pigments used for tinting mortar, cement, and concrete. A great variety of materials are used for theso purposes, including "blue billy" (residue left from roast- ing pyrite), ground slate and shale, and even culm from coal washeries. Dur- ing the past three years, there has been a definite trend among the producers of iron oxide pigments to push the sales of the better grades of colors for tinting mortars. Due to the amount of low-grade coloring matter that is re- quired to impart a strong color to concrete (in soro cases as high as 15 per cent of pigment is necessary) the strength of the cement may be materially impaired. The addition of some 2 per cent of the higher grades of iron oxide to the concrete mix imparts a brighter and stronger colcr, does not weaken the material, and in the end is not as expensive as the low-grade pigments formerly used. Iron oxide pigments occur in nature in various shades and colors, but the red pigments are the most important and account for the larger part of the total red pigments used.3/ The nomenclature of these red pigments is involved and the names given to them are descriptive of the shade rather than of origin, method of produc- tion or chemical composition. In most cases the red pigments under this class may occur naturally or may be produced by heating hydrous iron oxide pigments such as yellow ocher to a sufficiently high temperature to drive off the water of composition. They may also be prepared by fortifying naturally-occurring pigments with stronger natural or synthetic oxides or with coal-tar dyes (e.g. alizarine lake), Most of the mineral reds derive their color from the presence of ferric oxide (Fe2O3), the mineral hematite. This may be present in relatively small percentages, as in the red slates and shales, or it may constitute as much as 90 per cent or more of the material, as in Spanish red. The principal iron oxide pigments used in the manufacture of paint are discussed in the following pages.

May 1, 1932

By James F. O'Neill

Brown iron ore deposits in Quitman County , Ga . , were investigated by the Federal Bureau of Mines in cooperation with the State of Georgia , Department of Commerce , and the University of Alabama . Ninety- one holes were drilled , having an aggregate footage of 2,188 feet ; seventy- one holes penetrated 248 feet of iron mineralization . Average thickness of the ore zone was 3.5 feet under an average thickness of 14.7 feet of overburden . The drilling developed inferred reserves containing nearly 30 million long tons of crude ore with an average analysis of 28 percent iron plus minor quantities of manganese . Test work done by the Bureau on the crude ore samples indicated that they would upgrade by current log washer practice , with the use of a 1 /8 - inch screen , and yield 4.4 million dry long tons of concentrate with an average analysis of 52.1 percent iron plus manganese . The weight recovery obtained was 14.7 percent . Research studies made by the Bureau showed that the weight recovery would be increased by changing the screen size without any appreciable sacrifice of grade . The average weight recovery was increased to 18 percent with a 10 - mesh screen and 22.8 percent with a 20 - mesh screen . Screen tests studies indicated that there was no appreciable interlocking of the iron and manganese minerals and the clay and silica waste particles of the materials retained on a 200- mesh screen . Clay was prominent in micron - size slimes . Silica was deleterious in the minus 20 - mesh size .

Jan 1, 1965

By Frederick W. Horton

With large deposits of low-grade molybdenum ore and a latent market for molybdenum, which with development might perhaps equal that for tungsten, the United States has for years made no pro- duction of molybdenum ore worthy of mention. In fact, during the decade previous to 1914, there was no output of molybdenum ore in this country except in 1905, 1906, and 1907, when a few small lots of molybdenite and wulfenite were marketed." To ascertain why this possible source of economic wealth should remain undeveloped, the United States Bureau of Mines undertook an investigation in 1914, with a view of assisting the establishment of a molybdenum industry in this country. A preliminary review of the situation showed the following conditions: Briefly there was a lack of any considerable demand for molyb- denum for the one known use that might consume any large tonnage of it, that is, for the manufacture to certain alloy steels to which molybdenum imparts properties roughly similar to those produced by tungsten. It was at once evident that the market for molybdenum in alloy steels must be developed, or that extensive new uses for the metal must be created, before the demand would be sufficient to war- rant any extensive mining of molybdenum ore. Investigation showed that one of the chief factors in retarding the development of any demand for molybdenum by the alloy-steel trade was that manufacturers who might use, or might investigate the possibilities of using, the metal were kept out of the market by the fear of not being able to obtain steady supplies. On the other hand, those who might be interested in the development of some of the extensive low-grade molybdenite or wulfenite deposits in this country were prevented from doing so by the small visible demand and the fear that any large production would glut the market. Owing to these conditions the mining of molybdenum has in the past been confined almost entirely to small-scale operations on high-grade streaks of molybdenite ore, and the methods of recovery have been limited largely to cobbing and hand picking.

Jan 1, 1916

In 1970, the U. S. Bureau of Mines contracted with Theodore Barry and Associates, a management consulting firm, to perform a one-year industrial engineering study of working-face hazards in underground bituminous coal mines. The field data was accumulated from industrial engineering observations in fifty underground mines. Supporting data for the analysis was derived primarily from the Bureau's fatal accident reports for the years 1966 through 1970. This report, Industrial Engineering Study of Hazards Associated with Underground Coal Mine Production, consists of three main parts: 1) The Fatal Accident Reports Analysis, 2) The Industrial Engineering Analysis, and 3) Multiflow Process Charts and Standard Time Data. The Fatal Accident Reports Analysis (Volume I, Section II) is based upon individual USBM fatal accident reports for 1966-1970. These were read, coded and computerized in terms of 84 significant variables. Cross-tabulations of these variables have been used to identify major underground hazards and to quantify significant causal factors. A very strong relationship was found to exist between fatal accident occurrences and low task experience. This led to a recommendation for formalized training, certification and supervision programs for miners. Victim compliance with federal regulations, mine regulations and supervisor instructions was analyzed, indicating that supervisors provide the most crucial communication link to workers. Thus, every attempt should be made to ensure the competence of immediate supervisors in the industry. Analysis of roof fall variables revealed a fatal propensity on the part of the miners to work under unsupported roof or under support conditions that are marginal. The technical approach to the problem is to make it physically impossible for a miner to work under these conditions; the behavioral approach is to ensure adequate training and develop proper safety attitudes among the miners. The Fatal Accident Reports Analysis revealed a need for normalizing data to interpret the results more accurately.

Jan 1, 1971

By D. E. Shanks

This U.S. Bureau of Mines (USBM) research simplified an earlier hydrogen chloride (HCI) leach-sparge process developed by the USBM to recover reduction-grade alumina from domestic kaolin clay. Improvements were made by decreasing the initial leaching acid concentration from 25 to 20 pet, decreasing the leaching time from 1 to 2 h to 15 to 30 min, eliminating the solvent extraction step for Fe removal, and eliminating the step to recover the AI content of the bleedstream circuit. A 10-cycle bench-scale experiment of the simplified process showed that the ferric chloride (FeC13) concentration built up to 9.3 g/L in the recycle stream. This did not interfere with any of the unit operations or final alumina product purity because Fe forms stable soluble chloride complexes when sparged with HCI and is easily washed from the large aluminum chloride hexahydrate (ACH) crystals. The reduced leaching time and acid concentration did not decrease Al extraction.

Jan 1, 2010

By Jerry J. Gray

Transportation charges for mineral commodity movements in western Oregon and western Washington were determined mainly by a stratified random sample canvass of producers. Total 1965 mineral production value for this area was $53.3 million; the cost or charge to move this production from the mine to the consumer or to the point of consumption was determined to be an additional $38.7 million. Thirty seven companies were contacted as a sample out of a total population of 349; the statistically expanded sample production value deviated 3.6 percent from that obtained by the Bureau's annual canvass. The agreement between the sample results and the canvass totals demonstrated the effectiveness of the sampling method for obtaining data with a predesigned level of accuracy. For comparison, the north-central Idaho and western Montana area was studied, A random sample experiment was designed, but because of the dominance of a few major companies, a random sample technique would have required more visits to producers than if only the larger firms were contacted. Eighty-four percent of the 1966 mineral value ($198.6 million) was accounted for by interviewing 27 firms out of a total population of 199. Total transportation costs or charges for the area were $26.7 million. The significant difference observed between the relationship of minerals production value and transport charges between the two areas investigated can be attributed to the difference in the minerals produced. The western Oregon and western Washington region is a nonmetals-producing area as opposed to the predominance of metals production in the Idaho-Montana region.

Jan 1, 1968

A new series of reports called ?Mineral Perspectives" (MP's) has been initiated by the Bureau of Mines with the publication of MP-1 titled, "Far East and South Asia" by K.P. Wang and the staff of the Bureau of Mines. This new series parallels the creation of the recently announced "Minerals Commodity Profiles" (MCP?s). Both series are designed to provide current information on important sectors of the mineral economy to assist professionals in government, industry, and education in monitoring supply-demand relationships that have significant impact on our domestic economy as well as on the international scene. The orientation of the "Mineral Perspective" series is a geographic one which examines the mineral situation of a region or a country. The "Mineral Commodity Profile? series examines individual mineral commodities. They are in this sense complementary.

Jan 1, 1977

Minerals are a fundamental component of the Nation" material and economic base. Without a continuous supply of minerals to meet growing and changing needs, the basic character of our society would be very different. The importance of minerals to the United States was reemphasized by the Congress in I970 when it enacted the Mining and Minerals Policy Act, which stated that it is the continuing policy of the Federal Government in the national interest to foster and encourage private enterprise in (I) the development of economically sound and stable domestic mining, minerals, metal and mineral reclamation industries, (2) the orderly and economic development of domestic mineral resources, reserves, and reclamation of metals and minerals to help assure satisfaction of industrial, security and environmental needs, (3) mining, mineral, and metallurgical research, including the use and recycling of scrap to promote the wise and efficient use of our natural and reclaimable mineral recources, and (4) the study and development of methods for the disposal, control, and reclamation of mineral waste products, and the reclamation of mined land, so as to lessen any adverse impact of mineral extraction and processing upon the physical environment that may result from mining or mineral activities.,.

Jan 1, 1977

By H. C. Carpenter

This literature study of methods for desulfurizing residual fuel oil was conducted by the Bureau of Mines at the request of the Department of Health, Education, and Welfare. The sulfur compounds in residual fuels are believed to consist chiefly of condensed thiophenes and other polycyclic sulfur compounds. Hydrodesulfurization appears to be the most promising method for desulfurizing these oils and is the only method applicable to all types of sulfur compounds. There are indications in the literature that hydrodesulfurization without hydrocracking of residual oils may require higher pressures than used in present desulfurization processes, but no cost data and little experimental data are available on the higher pressure operation. Literature proposals for hydrogenating residual oils and heavy crude oils are exclusively for hydrocracking the oils to lower boiling products with accompanying partial desulfurization of the residual fuel fraction. Costs of the hydrocracking operations appear the closest available to probable costs of hydrodesulfurizing the oils, and have been reported (in 1955 to 1957) as $500 to $840 investment cost per daily barrel of capacity, with total operating costs of 70 cents to $1.10 per barrel.

Jan 1, 1963

By A. C. Richardson, G. D. Coe, B. M. Bird

"The Hull mine of the De'Bardeleben Coal Corporation is located in the Warrior field, in Walker County, Ala., about 25 miles northwest of Birmingham. The Mary Lee bed at this point is coking coal and has been used in the manufacture of by-product coke, but at present it is sold exclusively as a domestic and locomotive fuel.The data in this paper, which is the third in a series on the washability of Alabama coals,5 have been obtained in connection with an exhaustive study of coal preparation in Alabama now being conducted by the U. S. Bureau of Mines and the University of Alabama with the cooperation of the different coal operators. The paper contains screen-sizing and float-and.-sink tests of a representative sample of run-of-mine coal, and flakiness tests and crushing tests of certain sizes.In addition, complete analyses of the ¾-inch to 3/16-inch size, raw coal, together with ash fusibility tests of the float-and-sink fractions have been made; those results are given in Tables 1 and 2. Since they indicate that the pr ration problem, like that at Lewisburg, Ala., is one of ash reduction, the further tests and the discussion have been restricted to that subject."

Apr 1, 1931

By James F. O?Neil

Brown iron ore deposits in Quitman County, Ga., were investigated by the Federal Bureau of Mines in cooperation with the State of Georgia, Department of Commerce, and the University of Alabama. Ninety-one holes were drilled, having an aggregate footage of 2,188 feet; seventy-one holes penetrated 248 feet of iron mineralization. Average thickness of the ore zone was 3.5 feet under an average thickness of 14.7 feet of overburden. The drilling developed inferred reserves containing nearly 30 million long tons of crude ore with an average analysis of 28 percent iron plus minor quantities of manganese. Test work done by the Bureau on the crude ore samples indicated that they would upgrade by current lug washer practice, with the use of a 1i8-inch screen, and yield 4.4 million dry long tons of concentrate with an average analysis of 52.1 percent iron plus manganese. The weight recovery obtained was 14.7 percent. Research studies made by the Bureau showed that the weight recovery would be increased by changing the screen size without any appreciable sacrifice of grade. The average weight recovery was increased to 18 percent with a 10-mesh screen and 22.8 percent with a 20-mesh screen. Screen tests studies indicated that there was no appreciable interlocking of the iron and manganese minerals and the clay and silica waste particles of the materials retained on a 200-mesh screen. Clay was prominent in micron-size slimes. Silica was deleterious in the minus 20-mesh size.

Jan 1, 1965

By Frank B. Fulkerson

Three of the five primary aluminum producers in the Pacific Northwest have facilities in the region to make aluminum mill products. Only one of the three, however, produces a variety of shapes and forms. The principal reason for the lag in development of an aluminum mill products industry was found to be transportation cost. The long range outlook is for expansion, based mainly on growth of the western market for aluminum used in construction, containers and packaging, electrical applications, diesel trucks, mobile homes, and irregation pipe. Consumption of western aluminum mill products in 1985 is projected at 1.1 million tons, compared with estimated consumption of 250,000 tons in 1961.

Jan 1, 1965