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By Stephen D. Cramer

The Bureau of Mines conducted a series of in situ linear polarization measurements in high-temperature, high-pressure hypersaline geothermal brines at the Bureau of Mines Geothermal Test Facility in the Imperial Valley of California. The measurements represented an evaluation of the linear polarization technique for obtaining instantaneous corrosion rates of materials of construction in flowing hypersaline hydrothermal fluids that rapidly form scales on exposed surfaces. A special method was devised for use with the linear polarization technique that resulted in obtaining corrosion rates for 1020 carbon steel, 316 and 430 stainless steel, titanium, various nickel-based alloys, and aluminum 6061 under strong scale-forming conditions. The measurements also provided information on scale-deposition rates in various geothermal environments. Exploratory in situ potentiostatic polarization measurements were made in the flowing brines to qualitatively determine scale-deposition effects on the electrochemical measurements.

Jan 1, 1978

Reduce face methane concentrations and help prevent miners from working under unsupported roof while moving the curtain. Approach Use water sprays on the continuous mining machine to move and direct air to the face, and also provide appropriate installation guidelines for the most effective use of the system. I n laboratory tests and under actual mining conditions, the spray fan has proved an effective means of ventilation. Recent observations in the field, however, have shown that not enough technical information is widely available on proper installation of the spray fan. This Technology News is designed to rectify that situation by providing a concise guide for spray fan installation. How the System Works Good ventilation is essential for methane control. The spray fan system repositions regular water sprays to help the normal exhaust face ventilation do a more effective job. The various water sprays help in many ways: 1. Side sprays bring clean air along the side of the miner into the off-curtain corner.

Jan 1, 1983

By Rose L. Ballard

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are tables that show the principal nonfuel mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1982

By Donald R. Irving

ALTHOUGH the quantity of material handled at metal and nonmetal mines in the United States in 1962 was 2.7 billion tons, the same as in 1961, a larger proportion was waste. At metal mines, crude ore production declined 1 million tons and waste output rose more than 18 million tons; at nonmetal mines crude ore production declined 6 million tons and waste output rose 36 million tons. Copper and iron ore producers increased their share of crude ore and material handled from about three-fourths to four-fifths of the national metals total, and sand and gravel and stone producers in-creased their share of the nonmetals total, also from three-fourths to four-fifths. Six States-Arizona, California, Florida, Michigan, Minnesota, and Utah-each handled more than 100 million tons of ore and waste, and together they accounted for 43 percent of the U.S. total. When the large-volume construction materials (sand and gravel and stone) were excluded from the totals, four States-Arizona, Florida, Minnesota, and Utah-supplied over half of the material handled.

Jan 1, 1963

By P. J. Dallimore

The Bureau of Mines has calculated general time-dependent solutions for radon diffusion from cylindrical and slab rock samples containing uniform radium distribution. Results have been obtained for several sets of boundary conditions. The method is suitable for determining the effective diffusion coefficient and the effective porosity for radon.

Jan 1, 1983

By John R. Bartels, Dean H. Ambrose, Richard C. Wang

This paper presents the results of a study to verify and validate a computer model that represents and analyzes motions and hazardous events in a simulated three dimensional workplace. The purpose of the computer model is to support research that is investigating the safe speed range for the vertical movement of roof bolter boom arms to reduce worker injuries in underground coal mines. The information obtained for this paper is based upon a project that is investigating means to reduce workers risks of injury from exposure to mining machinery. The methodology being employed by the project includes human factors design considerations, anthropometric modeling and simulation tools, laboratory validation, engineering interventions, and collaboration with industry and an equipment manufacturer. The results of this study were used to (1) determine the input parameters that are unique to the mining environment and needed to develop a credible, computer-based, human-machine interactive model, (2) develop test methods to measure the required parameters, and (3) to refine the human-machine interactive computer model.

This chapter describes the adverse health effects associated with exposure to respirable coal mine dust. Epidemiological studies of underground and surface coal miners in the United States and other countries are discussed. Also discussed are animal studies that add to our understanding of particle deposition and retention in the lungs and associated disease responses. This chapter emphasizes studies that (1) were performed since the passage of the Federal Coal Mine Health and Safety Act of 1969 [P.L. 91- 173], (2) used standardized methods of exposure monitoring and disease classification, and (3) investigated exposure-response relationships between respirable coal mine dust exposure and disease. Several published review articles contain further discussion of health effects studies of coal miners [Attfield and Wagner 1992b; Petsonk and Attfield 1994; Cotes and Steel 1987; Merchant et al. 1986; Morgan and Lapp 1976; Morgan 1975].

Jan 1, 1997

By B. J. Dalton

This report gives general expressions for evaluating various thermo-dynamic properties applicable to a two-component system, including liquid-vapor equilibria. In addition, expressions are developed for some of the quantities useful in making thermodynamic consistency checks on phase equilibria data. These formulas were developed from the general principles of thermodynamics and are expressed in terms of the compressibility factor, which is assumed to be an explicit function of the molal density, the absolute thermodynamic temperature, and the composition.

Jan 1, 1968

By Motohisa Kanda

The time and amplitude statistics necessary to adequately describe electromagnetic (EM) noise in mines are illustrated through computer software techniques. They are 1) Allan Variance Analyses (AVA), 2) Interpulse Spacing Distributions (ISD), 3) Pulse Duration Distributions (PDD), 4) Average Crossing Rates (ACR) , and 5) Amplitude Probability Distributions (APD) . These statistics are illustrated using data taken from a rather large store of raw analog data recorded in operational mines. The curves generated for the illustrations characterize the noise environment in the mines from which the corresponding data were taken, and should aid in the design of reliable communication systems for such mines.

By R. J. Shanley

This report presents a computer code that has been developed by the Bureau of Mines for isolating naturally occurring clusters of data plotted on the unit hemisphere and testing these clusters against a probability distribution which admits elliptical symmetry about its mean. A listing of the computer code is provided along with an example output illustrating the delineation and analysis of clusters in fracture orientations measured in a porphyry copper deposit.

Jan 1, 1975

By K. K. Kershner

Important contributions can be made to conservation of natural resources by recovering mineral values from primary and secondary metallurgical slimes and flue dusts. This applies particularly to ultrafine mineral particles that escape recovery by conventional mineral dressing. In the interest of economy and conservation the Bureau of Mines is investigating fundamental properties of ultrafine mineral values in slimes as a means of developing new or improved methods of mineral recovery. The work described in this progress report was carried on in the Bureau's laboratories at Rolla, Mo., from 1951 to 1953. The mineral material used as a subject for study was tin-ore slimes. DESCRIPTION OF TIN SLIMES The tin slimes consist principally of quartz, with appreciable quantities of tourmaline and sericite mica and small amounts of cassiterite, pyrite, hematite, and arsenopyrite. The tin content is approximately 0.5 percent.

Jan 1, 1954

By R. H. Grau, S. B. Robertson, R. B. Krog, T. P. Mucho

Stone mines represent the highest percentage of operating underground nonmetal mines in the United States. With the introduction of stricter Diesel Particular Matter (DPM) regulations, large-opening underground room-and-pillar stone mine operators are faced with implementing one or more alternative methods to reduce concentration levels including: install and maintain an effective ventilation system; install lower DPM emission diesel engines; the adding of DPM filters. The National Institute for Occupational Safety and Health (NIOSH) is actively researching various aspects of fan and stopping designs in an effort to improve the ventilation of these mines. NIOSH has identified and further developed three alternative ventilation methods for use in large-opening underground mines: split-mine, perimeter, and unit-ventilation. This paper describes the implementation of the three methods with respect to their use in mines of various levels of development.

By Carla A. Kertis, Alan A. Campoli, Claude A. Goode

This Bureau of Mines study was conducted to obtain a better understanding of the coal mine bump problem and its effect on underground coal mining in the Eastern United States. To accomplish this, information was collected on the geologic conditions, mining techniques, and engineering parameters at five bump-prone mines. Two geologic conditions have been found to cause the occurrence of bumps in the Eastern United States: (1) relatively thick overburden and (2) extremely rigid strata occurring immediately above and below the mine coalbed. Additionally, the probability of bump occurrence is increased by certain mining practices that concentrate stresses during retreat mining, in areas where geologic conditions are conducive to bumps. Mining plans that permit the development of pillar line points or long roof spans that project over gob areas should be avoided because these features may contribute to the occurrence of bumps.

Jan 1, 1987

By P. L. Woolf

Oil was successfully injected into the tuyeres of the Bureau of Mines experimental blast furnace. Determinations were made for the minimum oil addition necessary to permit the maximum available blast temperature of 2,250° F. and the maximum oil rates at blast temperatures of 1,900°, 2,000°, and 2,100° F. From these tests, the upper and lower levels of high-temperature heat input, which limit the smoothly operating furnace, were established. Substantial coke saving was realized with maximum oil injection. Oil-to-coke replacement ratios have been calculated for various conditions, and oil is compared with natural gas and moisture in somewhat general terms. A study of the effect of variations in slag volume and basicity on the sulfur content of the metal at high sulfur loads was made.

Jan 1, 1963

By Lloyd A. Morley, Robert Stefanko

Table

Jan 1, 1974

By Donald M. Hausen

Diamond-bit performance and cost data accumulated by the Bureau of Mines in core-drilling schists reveal significant trends of economic interest. Low-quality, small-size drill bort were the most economical. The percentage of core recovery, type and size of bit, and bit matrix are also correlated with bit performance and costs. Detailed analyses of the factors affecting diamond-bit performances and costs are assessed in the tables, graphs, and discussion.

Jan 1, 1956

By A. C. Johnson

The Ellington manganese deposit in Reynolds County J Mo., had been known for some time; and limited exploration, consisting of test pitting and sinking a shaft 54 feet deep on the property, had been done by private interests. Late in 1941, the Bureau of Mines cleaned, deepened, and sampled many of the existing pits and dug and sampled 27 new ones. The shaft was unwatered and sampled, and several pockets of manganese ore were trenched to determine their extent. Samples were analyzed and beneficiation tests on 1 ton of the ore were made at the Rolla, Mo., station of the Bureau of 'Mines. Results of the investigation indicated that the deposit was small and low in manganese content.

Jan 1, 1948

By W. Blake, J. K. Whyatt, T. J. Williams

Researchers at the U.S. Bureau of Mines collected and analyzed over core measurements and other indicators of in situ stress characteristics at the Lucky Friday Mine, Mullan, ID. An analysis of these data revealed that significant local variations in in situ stress are present in this mine and that these variations existed prior to mining. High stresses were found to be associated with the most competent strata and a locked section of a fault. An estimate of the predominant stress field was developed for mine-wide modeling. The estimate shows that the greatest principal stress was oriented north of northwest. This information should provide a basis for mine-wide structural modeling of the Lucky Friday Mine and should generate important insights into localized stress conditions, which may significantly affect both local and mine-to-mine variations in seismicity induced by excavation.

Jan 1, 1995

Improve the safety, reliability and overall effectiveness of mine stench warning systems and to provide a means of remote control stench injector operation. Approach Industrial gas odorants were analyzed for their suitability for use in mine stench warning systems. A prototype stench injector capable of precise flowrate control was designed, fabricated, and tested using the odorant chosen as having the most favorable properties. Based on the results of the field tests, a second generation injector was developed. The second generation unit features optional remote control operation, and in addition, is simpler to refill and is less expensive than the original injector. A complete second generation system, consisting of two manually operated injectors and one remote controlled injector was in-mine tested through actual mine fire drills. How It Works Ethyl mercaptan mixed with Freon is the predominant stench agent used in the U.S. underground metal and nonmetal mines. However ethyl mercaptan's toxicity,

Jan 1, 1982

CESIUM metal production increased sharply in 1963. Domestic Production.--Cesium metal was produced by The Dow Chemical Co., Midland, Mich., MSA. Research Corp., Callery, Pa., and by Penn Rare Metals, Inc., Revere, Pa. American Potash & Chemical Corp., Trona, Calif., produced some combined cesium and rubidium. This company, Penn Rare Metals, Inc., and Rocky Mountain Research, Inc., Denver, Colo., produced various cesium compounds. Complete production data on cesium and rubidium and their compounds were not available for publication. Consumption and Uses.-Substantially more pollucite was consumed to produce cesium metal and compounds in 1963 than in 1962 but the overall consumption of pollucite continued to be small.

Jan 1, 1964