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By Jacqueline A. McClaskey

The U.S. Bureau of Mines Information and Analysis Directorate collects world-wide data on virtually every commercially important nonfuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The Bureau's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the U.S. Bureau of Mines survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1993

By G. W. Jones, R. E. Kennedy

"INTRODUCTION Information relative to the ignition temperatures of acetylene and acetylene-air mixtures has become of particular interest recently due to a number of explosions that have occurred in 500-pound, double-rated, medium-pressure acetylene generators in shipyards on the West coast. Various suggestions have been made as to the causes of these explosions prominent among which has been that air finds its way into the acetylene generators during abnormal operation or that air remains in the carbide hopper of the generator following the purging and charging operations.This raises the question as to how and to what extent the presence of small percentages of air in acetylene affects the ease of ignition of such mixtures at the various operating pressures of the acetylene generators. The range of operating pressures in the 500-pound, double-rated generators involved in the explosions may vary from below atmospheric to 15 pounds gage.The present report gives the results of an investigation made to determine the effects of pressure on the ignition temperature of pure acetylene and of acetylene containing varying percentages of air:EXPERIMENTAL Apparatus A preliminary investigation showed that a heated quartz surface gave lower ignition temperatures than other material tested.A ""hot-spot"" method of ignition was found desirable in the case of the acetylene mixtures since the violence of the explosions was reduced by keeping most of the test mixtures at room temperature. Explosive violence was reduced further by using an ignition tube 17 mm. or less in diameter."

Mar 1, 1945

Federal lands often contain extensive mineral resources and decisions affecting access to those lands are made with knowledge of the possible minerals-related consequences. Information is provided to the Bureau of Land Management (BLM) in this report for use in preparing environmental impact statements on the Western Mojave Management Area (WMMA) and the Desert Tortoise Priority Habitat (DTPH). To augment U.S. Bureau of Mines (USBM) efforts such as the Mineral Assessment of the Planned Foil Irwin Expansion, Modified Silurian Valley Alternative, San Bernardino County, California which is in progress, and the Economic Analysis of the Minerals Potential of the East Mojave National Scenic Area; California, the USBM studied mineral deposits and estimated the potential impacts of mining in a segment of the California desert; the 8.7-million-acre WMMA, an area which includes the 1.2-million-acre Desert Tortoise Priority Habitat (DTPH). In addition, this information is intended to assist administrators, legislators, and the concerned public in understanding the economic importance of mineral resources in the California desert, especially that portion designated as the WMMA. See figure 1.

Jan 1, 1993

By Frederick C. Trutt

A guide to the development and utilization of an interactive mine-power-system fault program (Z-bus by algorithm) is presented. Theoretical foundations, as well as implementation considerations are discussed with respect to the mine-power system. Alternative Kron reduction techniques are presented along with a triangular-storage method for storage conservation. Program capabilities include the analysis of balanced and unbalanced (line-to-line, line-to-ground, and line-to-line-to-ground) fault situations using symmetrical component theory. To account for phase shifting in delta-wye transformers and zero-sequence network constructions, transformer and load configurations are specified by the user. The positive-and zero-sequence connections needed for network conformity are automatically constructed with the required impedances.

Jan 1, 1979

By S. Ralph Austin

This Bureau of Mines investigation determined the effects of so-called annealing at high temperatures on radon-222 emanation from domestic uranium ores. Concurrently, a method was developed for closely estimating the emanation coefficients of hot samples from measurements of their gamma activity after cooling. Emanation coefficients of 102 samples from 14 domestic areas of past, present, and possible future uranium production were investigated using modifications of the closed-can, gamma-only assay method at and after cooling from 100° to 1,000° C. True annealing probably does not occur below 500° C. In limited investigations at 500° C and above, effects of annealing are masked by the effects of other parameters. Emanation is commonly less at one or more of the steps investigated in the 100° to 500° C range than before heating. This decrease is tentatively attributed to water loss at temperatures dependent upon the minerals present. The average sample emanates least at 300° C; emanation increases with higher temperatures to at least 900° C. Emanation decreases sharply on cooling, but it is partially restored by prolonged exposure to the atmosphere at room temperature. Higher than average emanation of coffinite ores at 500° C and above may be related to destruction of the coffinite crystal structure.

Jan 1, 1979

By Jacqueline A. McClaskey

The U.S. Bureau of Mines (USBM) Information and Analysis Directorate collects worldwide data on virtually every commercially important non fuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The USBM's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the USBM survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1993

By R. H. Lien

The Bureau of Mines developed a flue gas desulfurization process as part of its goal of minimizing the undesirable environmental impacts associated with energy and mineral-processing plants. The modified citrate process involves absorption of sulfur dioxide (S02) in a buffered citric acid solution. The S02-loaded solution is regenerated by countercurrent contact with steam in a packed tower. The wet S02 product is then dried and can be liquefied or further processed to make sulfuric acid. Test data from process investigation unit studies are presented. Material balances, flowsheets, and cost estimates are given for recovering S02 from copper smelter reverberatory gas, lead smelter sintering machine tail gas, and power-plant stack gas. Operating cost estimates show the process will add $0.04 per pound of copper, $0.01 per pound of lead, and $0.015 per kwhr to the cost of the respective operations. These costs could be substantially reduced if a source of waste heat was avail-able to provide the process steam requirements.

Jan 1, 1982

By W. E. Robinson

Sixty samples, selected from a 2,300-foot core of the Green River Formation in Colorado, were studied to ascertain differences in the structure of the organic material present in the oil shale samples. Emphasis was placed upon relating differences in the aromatic content of the insoluble kerogen and the alkane content of the extractable material obtained from the selected samples. The methods used in determining these differences consisted of fractionation of the soluble material, carbon and hydrogen analysis, volatile material determination, carbon residue determination, oxidation rate determination, and infrared analysis. In general, it was concluded that the organic material in this core does vary in chemical structure and that same of these variations resulted from factors related to depth of burial. Other observed changes in structure of the organic material were not depth-dependent and resulted from other factors such as source material variations, biological alterations, or ecological differences.

Jan 1, 1971

By Edward F. Divers

This Bureau of Mines report describes the results of a laboratory evaluation of a mechanical dust collector (scrubber) suitable for underground coal mine applications. The scrubber was developed by the Mining Research and Development Establishment (MRDE), Burton-On-Trent, England, and tested at the Federal Bureau of Mines Pittsburgh Mining and Safety Research Center (PMSRC) as part of a technical exchange program. The 2,000-to 8,000-cfm scrubber consists of an electrically driven vane-axial fan, water sprays, a 2-inch-thick, loosely knit stainless steel wire filter panel, and a water droplet eliminator. The dust-laden airstream travels axially through the water sprays, filter panel, fan, and eliminator. Slurry water drains into a sump where a belt-driven pump recycles it back to the sprays. Fractional breakdown tests showed a maximum dust collection efficiency of 96 pct of respirable-size (less than 7 µm) coal dust at 2,000 cfm. Efficiency decreased with increasing airflow; for example, to 91 pct at 6,000 cfm. Following these tests the original wire panel was replaced with a similar but smaller panel developed at PMSRC; a marked improvement in dust collection occurred at all flow rates tested.

Jan 1, 1979

By J. B. Gayle

A 1/2-ton experimental coke oven was installed ac the Bureau of Mines Southern Experiment Station, Tuscaloosa, Ala., in 1948. Designated as the Tuscaloosa oven, this unit features a 17-inch carbonizing chamber, globar heating elements, and silica-brick walls designed to simulate as closely as possible the carbonizing conditions for commercial slot-type ovens. Because of the small force exerted on the oven walls in most tests conducted to date (probably owing to the practice of charging coals and blends at a moisture content approximating that normal to commercial plants operating in this district), little information has been obtained about expansion properties. Two sole-heated ovens have therefore been constructed and used as supplementary equipment for determining the expansion properties of coals tested in the Tuscaloosa oven. The reasons for constructing the Tuscaloosa oven, the details of design, the operating, characteristics of the oven and the reproducibility of results have been discussed in previous publications. 3 4 5/ The present report deals with the effects of substituting various high- and low-volatile coals for components of a selected base blend carbonized under conditions similar to those normally used for producing foundry coke. Results of tests of 11 coals and 14 blends indicate that several blends tested rave cokes having physical properties very similar to those produced from the reference blend.

Jan 1, 1957

By Charles L. Kimbell

In overview, 1988 appeared to be the best year for the world's mineral industry since 1980, although the all-important petroleum component suffered severely from low prices. With this notable exception, the traditional statistical measures of mineral industry performance, namely production, trade, and consumption, reflected growth in most elements of the world mineral industry from crude material extraction through the gamut of downstream processing. Moreover, the growth was reasonably well distributed geographically, with many countries sharing in the substantial upturn in activity. World crude mineral output value was estimated at over $1,272 billion in current dollars ($1,090 billion in constant 1983 dollars). The value added by the processing component of the mineral industry raised the total value of the industry's output to an estimated $3,057 billion in current dollars ($2,620 billion in constant 1983 dollars). Less easily assessed was the value of mineral commodities moving in 1988's international world trade, particularly because of the declines in world crude oil and refinery product prices. It remained to be seen if increased volume and value in nonfuel mineral and coal exports, coupled with an increase in the volume of oil exports, would be adequate to offset the drop in oil prices. Whether or not the value of world mineral commodity trade topped the 1987 level of over $498 billion, an increase in the volume of mineral commodity trade was almost assured. Similarly, although comprehensive statistics were not avail-able on consumption of all mineral commodities in all countries, available data on selected major commodities in selected major countries suggested that not only had output of most mineral commodities advanced, but so too had consumption levels for most commodities.

Jan 1, 1990

By G. W. Birge

Carbonizing properties of the principal coalbeds of Elk, Clarion, Jefferson, Clearfield, and Centre Counties, Pa,, are described in this Bureau of Mines report, Twenty-six samples, representing the Upper Freeport, Lower Freeport, Upper Kittanning, Middle Kittanning, Lower Kittanning, and Brookville beds, were carbonized by the Bureau of Mines--American Gas Association (BM-AM) method, and yields of products and physical properties of cokes were determined. Expansion or contraction of the majority of the samples was measured in the Bureau of Mines sole-heated oven. Chemical analyses, agglutinating values, and free-swelling indexes are given for all samples. In this area the coals generally are characterized by high sulfur and moderately high ash content, and their suitability for metallurgical use would depend largely upon satisfactory cleaning. The samples from Elk, Clarion, and Jefferson Counties were high-volatile A bituminous In rank, whereas, most samples from Clearfield County and all those from Centre County were of medium-volatile rank. Coals from Clarion County had dry, mineral- matter-free fixed-carbon contents ranging from 56.5 to 60.3 percent and were weakly coking. With the exception of two samples which contained excessive ash, the medium-volatile coals of Clearfield and Centre Counties were strongly coking and, as indicated by sole-oven expansion results, would require blending with lower rank coal to avoid oven damage.

Jan 1, 1963

By Eugene Frey

The Romur is one of several properties in the Copper Mountain mining district, Fremont County, Wyo., that contain scheelite deposits. The district lies on the southern slope of the Bridger Mountains, 18 miles northeast of Shoshoni and 15 miles from the rail point at Bonneville on the Chicago, Burlington & Quincy Railroad (figs. 1 and 2). The tungsten deposits occur in a zone of pre-Cambrian schists and gneisses that have been cut by numerous basic dikes and granite pegmatite dikes. Scheelite occurs in lenses and pods that lie parallel to the foliation and bedding in the metamorphic rocks. The more important deposits are found in a lime-silicate rock consisting primarily of zoisite but with small quantities of quartz and carbonate. Scheelite was found in December 1941, and the area was mapped by the U. S. Geological Survey early in 1942. In November 1942 the Bureau of Mines commenced work on the Stardust-Comet group for the purpose of developing reserves for war requirements. The initial work consisted of driving an alit in the ore zone a distance of 109 feet. This zone was sampled during the progress of the work, and subsequently surface and underground exposures on adjoining properties also were sampled (figs: 5, 6, 7, and 8). One hundred twenty-four samples were obtained. Sample and assay data are shown in tables 2, 3, and 4.

Jan 1, 1950

By James A. Whelan

The Bureau of Mines sponsored research studies of variables in rotary drilling, done in the Department of Mineral Engineering, University of Minnesota. By studying carefully controlled drilling with good instrumentation, it was hoped to obtain a better understanding of rock failure during drilling and of the stresses in drill bits during drilling. Experimental procedures and equipment are described. From these studies it was concluded that 1. Thrust requirements, other things being equal, are proportional to the total length of cutting edge in the bit. 2. Data from penetrating a wedge into rock under thrust only are not directly applicable to rotary drilling. 3, In rotary drilling the initial wear on a bit greatly decreases penetration rate under any given set of conditions; however, after initial wear the effect of wear on penetration rate is reduced. 4. An increase in rotary speed increases the overall penetration rate but decreases the penetration per revolution. 5. An increase in thrust increases the overall penetration rate and the penetration per revolution. 6, Torque on a drill bit is proportional to both penetration rate and bit diameter. 7. For small-diameter holes full-hole drilling will save both drilling time and energy compared with pilot drilling followed by reaming; for large-diameter holes pilot drilling-reaming is advantageous in both respects,

Jan 1, 1962

By W. W. Adams, V. E. Wrenn

"Production of explosives in the United States during the calendar year 1935 decreased 2 percent from 1934, according to reports covering all companies engaged in the manufacture of explosives during those years.Reports from manufacturers showed a total production of 308,381,250 pounds of explosives; this quantity included 39,170,016 pounds of permissible explosives 5/ 200,323,559 pounds of high explosives other than permissibles, and 68,887,675 pounds of black blasting powder of which 34,222,625 pounds were granular powder and 34,665,050 pounds pellet powder.Coal mines consumed 89 percent of the total production of blasting powder, 99 percent of the total output of permissible explosives, and 11 percent of the output of other high explosives.The metal mines of the United States used 28 percent of all high explosives other than permissloles, less than 1 percent of all permissibles, and 1 percent of all black powder produced.Quarries and nonmetallic-mineral mines consumed 17 percent of the high explosives other than pormissibles, less than 1 percent of the permissible., and 3 percent of the blasting powder.Construction work required the largest quantity, 40 percent of all high explosives manufactured during the year. Less than 1 percent of the permissibles and 6 percent of the black powder produced during 1935 was used in construction work."

Nov 1, 1936

By James P. Ulery

A Bureau of Mines geologic study of Pennsylvanian and Permian coalbeds in southwestern Pennsylvania was undertaken to determine the effects of coalbed geology and petrology on in situ coalbed gas contents. Data were obtained from 18 coreholes from parts of four 7.5 ' quadrangles in southwestern Washington and northwestern Greene Counties, and from a single corehole in Westmoreland County. A total of 88 samples from 24 coalbeds were collected for direct-method testing to determine gas content. The samples were also analyzed for petrographic composition, chemical composition, and vitrinite reflectance values. Corehole information was used to generate isopach maps and geologic cross sections useful in data interpretation. Results of the investigation show that coalbed gas content is related to vitrinite reflectance, but not to petrographic composition. Gas contents are also influenced by other geologic factors such as roof rock lithology and competency, and location with respect to local fold structure.

Jan 1, 1989

By J. Weinberg

This Bureau of Mines report presents data on the changes in the use of steel in motor vehicles over the past 35 yr. Sources of supply of steel for the automotive sector have shifted from almost all domestic in the 1950's to about 50% domestic and 50% foreign in the 1980's. Downsizing, design changes, and substitution of lighter weight materials to achieve energy efficiency also contributed to the market loss of the domestic steel industry. Although plastics and aluminum have displaced some steel in motor vehicles over the years, heavy low-carbon steel is now being replaced most rapidly by lightweight high-strength steel. If the percent of domestic steel used in motor vehicles had not declined since 1950, domestic industry would have supplied 9.3 million more short tons of steel than it supplied in 1985. Downsizing and design changes accounted for 43% of the loss; steel imports, 32%; and substitution of plastics and aluminum, 25%. In 1985, the total value of market share lost by U.S. steel producers was $5.1 billion, of which $1.6 billion was lost to foreign steel producers and automobile manufacturers. Through aggressive marketing and increased efficiency, however, the domestic steel industry may be able to recapture some lost markets, as applications for high-strength steels expand, and as foreign-owned automotive plants in the United States provide fresh sales opportunities.

Jan 1, 1988

By Charles White Merrill

Silver consumption in the arts and industries of the United States during 1930 and 1931 has remained remarkably near the high level established in 1929. Undoubtedly the sharp drop in the price of silver has been an important factor in supporting consumption, but silver's peculiar properties and uses probably have been an even more compelling reason for its sustained utilization. In its most important use - sterling silverware - it seemingly has most serious competition, but well established tradition protects the demand for sterling ware and the law forbids the term "sterling" to be applied to any material not containing at least 92.5 per cent silver. The photographic industry is dependent upon properties of certain silver salts possessed by no other material. Consequently silver is indispensable to all photography, including the huge motion picture industry. Other uses for silver could be listed which, because of special features, likewise have tended to maintain the consumption of silver in the arts and industries of the United States. The figures which this report makes available for the first time are the detailed silver consumption figures for the arts and industries of the United States for 1930 and 1931. These figures have been tabulated with the previously published(3) figures for 1928 and 1929 thus presenting a 4-year statistical record of silver consumption. All quantities are given in troy ounces, 1,000 fine.

Jan 1, 1932

By John W. Cole

The Butte district has been the principal producer of metallurgical-grade manganese in the United States since World War I. Manganese dioxide nodules are produced from rhodochrosite ore by concentrating the rhodochrosite and roasting the concentrate in rotary "cement-type" kilns. The Anaconda Copper Mining Co. is the only producer at present. Under the stimulus of a purchasing program administered by Metals Reserve Company during World War II, however, several independently owned or operated mines (including the Norwich) produced manganese carbonate ore. These mines were examined in Juno 1949 by John W. Taber, mining engineer, Bureau of Mines. A core-drilling program to develop ore in the Norwich mine was recommended and approved. drilling was completed early in 1950. This report gives factual data obtained.

Jan 1, 1951

By R. P. Adams

Because of the extreme interest in materials with high melting temperatures and the advantages offered over the powder route for making high-density material, arc-melting and centrifugal-casting methods were investigated for preparing shapes of hafnium carbide with and without excess carbon. Highly satisfactory equipment was constructed and efficient operating procedures were established. Also, methods for preparing consumable electrodes and shrink-tolerant graphite molds were developed. Although crack-free hafnium carbide (6.3 weight-percent carbon) shapes were not made, coherent castings containing 9 to 13.5 weight-percent carbon were produced; the same compositions were shown to be resistant to thermal shock. Selected physical and chemical tests were performed on castings chosen for investigation by chemical and nondestructive inspection techniques. Electrical conductivity and thermal expansion measurements were made. Measurable oxidation of all the compositions studied was observed to start between 500° and 600° C. Attack by nitrogen, however, did not occur until temperatures exceeded 2,000° C. A linear relationship of the logarithm of the diamond pyramid hardness to the temperature was noted. Considerable scatter of the bend-rupture strengths at room temperature and of the tensile strengths up to 2,000° C was found. However, at the latter temperature and above, a definite relationship of strength to temperature was observed and some ductility was noted.

Jan 1, 1968