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By S. C. Schaefer

The Bureau of Mines investigated tIle standard Gibbs energies of formation, 8Gfo, for MllF2 (manganese difluoride) and CoF2 (cobalt difluo-ride). High-temperature galvanic cells employing CaF2 (calcium diflu-oride) as the solid electrolyte were used to measure the open-circuit potentials for the cell reactions ?

Jan 1, 1985

By McHenry Mosier

Mercury is one of the strategic metals the supply of which has been raised from critical uncertainty to more than enough for essential demands. Work by the Bureau of Mines has contributes substantially to increased production of mercury in the United States and to consequent accumulation of Governments stock. Other contributing factors were higher prices for mercury and Government loans to operators. The Bureau has undertaken 15 exploration projects, 13 of which have been completed. This work comprised 40,307 feet of drilling arid 35,082 linear feet of sure ace trenching and has indicated commercial ore containing 37,400 flasks of mercury and marginal ore contain¬ing 29,200 flasks - a total of 66,600 flask , equivalent, respectively, to domestic production at 50,000 flasks per year for 9 months , 7 months, and 16 months. Early in 1944, as Government stocks had become adequate, domestic production was gradually curtailed cancellation of Government contracts for the purchase of mercury and Government control of labor and operating supplies.

Jan 1, 1944

By Daryl E. Radcliffe

Ninety-seven roof bolts were instrumented with strain gages and resin-grouted in three areas of the Bear coal mine, Somerset, Colo., by the Bureau of Mines. Measurements taken with these instruments indicate roof support is achieved through a combination of point suspension and resistance to vertical and horizontal stresses caused by localized shearing in the roof. The localized shearing results in bending of the bolts, yielding due to high vertical stresses, and the transfer of high loads to the bolt head or plate.

Jan 1, 1980

By Jon C. Volkwein

Dust concentrations inside and outside enclosed cabs on several types of mining machinery were measured by the Bureau of Mines. Results indicated that properly enclosed cabs can offer significant dust protection for machine operators. Recommendations for improvements in cab technologies were discussed.

Jan 1, 1979

By R. V. Ramani, A. S. C. Owili-eger

System Size N,NX Number of blocks in x-direction M,NY Number of blocks in y-direction NTIMES Number of systems to be simulated LENGTH Length of medium WIDTH Width of medium THICK Thickness of medium NZONE Number of material zones Medium Properties XPERM(I,J) Permeability in x-direction at the point (i,j) YPERM(I,J) Permeability in y-direction at the point (i,j) PHI Medium porosity T Medium temperature Gas Properties PURL, VISCOG Gas viscosity Z Gas deviation factor BETAG Gas compressibility coefficient Initial and Boundary Conditions IBC Initial and boundary conditions NPRESS Number of specified pressures NQUAN Number of specified quantities FACEP Face pressure RESEP Reservoir pressure

Jan 1, 1974

By J. Douglas Causey

In 1986, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied the 7,940-acre Southern Otay Mountain Wilderness Study Area (CA-060-029), and the 5,750-acre Western Otay Mountain Wilderness Study Area (CA-060-028) in order to evaluate their mineral resources. The wilderness study areas are located in San Diego County, CA, about 20 miles southeast of San Diego. No mineral resources were identified in the Southern or Western Otay Mountain Wilderness Study Areas, based on literature, field observations, and sample results. The wilderness study areas are underlain by a complex blend of Late Jurassic, moderately metamorphosed sedimentary and volcanic rocks. Evidence of mineralization is not obvious.

Jan 1, 1987

By Eliot J. White

The physical properties and clay mineral content of the major oil-producing formations in the Powder River Basin of Wyoming were determined by analyses of cores from 100 wells. Interrelationships were established among permeability, restored water saturation, clay content, and bulk swelling capacity of the crushed sample and used to estimate the susceptibility of the formations to water damage. The ratio of water permeability to gas permeability (kw/ki) offers a convenient scale for semiquantitatively estimating the water sensitivity of sands. The irreducible water saturation was also found to have a similar relationship to the clay mineral content and the water sensitivity of the sands. The average relation of water permeability to gas permeability is different for each sand, as shown by the curves, and the relative positions of the curves indicate the degree of water sensitivity of each sand from which the susceptibility to water damage may be estimated. How accurately these estimates show formation behavior under field operations will not be known until studies of field performance can be made. The water permeabilities of the Muddy, Minnelusa, and Tensleep sands average about the same as the gas permeabilities, and these sands are classified as insensitive. The water permeabilities of the Sussex and Shannon sands, at the other extreme, are much less than the gas permabilities [when average ki is 30 millidarcys (md), kw is 6.1 md], and these sands are classified as highly water sensitive. The sensitivities of the five other sands are between these extremes.

Jan 1, 1962

By M. A. Elliott, F. W. Brown

"INTRODUCTION During the recent war the Bureau of Mines, at the request of one of the armed services, investigated the hazards that night be encountered 5n handling perchloric acid, particularly if spilled on certain materials. The hazardous nature of perchloric acid when mixed with reducing agents had been known qualitatively, but it was desired to obtain quantitative data on the explosion hazards of such materials. Accordingly, tests were made to determine the sensitivity of mixtures of perchloric acid and oxidizable materials to initiation by heat, impact, sparks, flame, and explosive impulses. This report summarizes the results of those tests.PROPERTIES OF PERCELORIC ACIDAnhydrous perchloric acid is a colorless,hygroscopic, volatile, mobile liquid that fumes in the air. The anhydrous acid is unstable at ordinary temperatures, and therefore the commercial acid is a water solution containing either 60 percent or 70 percent by weight of the anhydrous acid. The commercial acid is widely used in chemical analysis, frequently to oxidize organic material. If proper precautions are not observed, such an oxidixation may become exceedingly rapid and result in an explosion. Several such explosions involving the acid are mentioned in the literature. 4, 5, 6/"

Jan 1, 1948

By L. A. Grant

This paper describing the concentrator practice of the Montana Mines Corporation at Helena. Mont., is one of a series of articles on milling methods and costs being prepared by the United States Bureau of Mines. The Spring Hill mine and mill are located 4 miles south and west of Helena, Mont., near the head of Grizzly Gulch. The mine portal is on the east slope of the gulch, and the mill is directly opposite on the west slope. Grizzly Gulch is one of the tyro gulches which unite at the south end of Helena to form Last Chance Gulch, on which the main street of Helena is built.

Jan 1, 1931

By G. L. Oldright, Virgil Miller

"ACKN0WLEDGMENTSThe data given in this paper were collected at the Bunker Hill smelter through the courtesy of Stanley A. Easton, the vice-president and general manager, Frank M. Smith, the smelter director, and with the assistance and cooperation of A. F. Beasley, the smelter superintendent, and his staff members.THE BLAST FURNACE AND PLANTThe general lay-out of the recently built (1917) Bunker Hill plant has been given in the technical press in articles that were cited in Report of Investigations 3088. In addition it may be noted that the description of an ideal smelter given by Riddell 5 a year later fits the Bunker Hill smelter very well, with some changes, such as the location of the stack, made necessary by topography. For purposes of this article on the blast furnace it may suffice to state that the plant is one of the ""side hill location"" type. The various successively lower benches may roughly be considered as made for (1) the stack, (2) Cottrells and bag houses, (3) Dwight and Lloyd sintering machines with the equipment or bins for handling or mixing the feed and storing the finished product, sinter, and (4) the blast furnace feed floor with a slightly rising gradient to the bottom of the bins for sinter, feed, and take. The lowest bench (5) might be considered that of the blast furnace tapping floor at which or at appropriately slightly lower elevations are located the units for softening, refining, and treating precious metals, and for casting and loading lead. A very careful study of grades was made in order to be able to handle the products easily. All units were left with at least one end open to permit expansion of the plant, it desired, and each unit was separated from the other, evidently so that the operators on one level would be annoyed as little as posssible with the products made on another."

Apr 1, 1931

By Larry G. Stolarczyk

This report deals with information regarding a new Medium Frequency (MF) Wireless Communication System for underground mines. This new telecommunication system works on low loss electromagnetic wave propagation modes which allow it to provide quality radio communications almost anywhere in a mine. Tests show the MF system can provide improved safety and managerial control, increased productivity, better organizational team-work and reduced maintenance cost; furthermore, MF's unique design allows for easy installation at a minimum cost. This paper covers the following: 1) MF design plan, 2) Overview of mine radio communications systems, 3) Preparations needed for designing an MF system, 4) MF equipment, 5) MF installation, 6) MF design considerations, 7) MF design specifica¬tions, and 8) Recommendations dealing with MF system. Experiments in four mines are illustrated to demonstrate the success and via¬bility of the MF system. The mines range from small (500 tons/day) to large (67,000 tons/day) capacity and represent several different mining methods. The MF Wireless Communication System represents an advancement in mining communication and the groundwork for other advanced mine systems.

Jan 9, 1984

By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1955 was made under a co-operative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 116 samples of aviation gasoline and for 38 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers' 1955 production in their laboratories and the results submitted to the Bureau of Mines for compilation. The products of 20 manufacturers of aviation gasolines and of 16 producers of aviation jet fuels are represented.

Jan 1, 1956

By W. H. Lewis

This Bureau of Mines report and its companion report (Information Circular 9074) have been prepared as a complete reference on underground coal mine lighting. This report discusses the fundamentals of light and its interrelationship with the visual process. The purpose of the report is to insure an understanding of the numerous complex and interrelated factors that must be considered to design and implement a mine lighting system that will satisfy human needs for good vision and comfort. Topics include history, objectives, and technical considerations of coal mine lighting; light physics; light and vision relationships; and disability and discomfort glare.

Jan 1, 1986

"Human accidents are caused by production accidents, generally ones (such as derailment of cars, falling rock, etc.) that have occurred numerous times before an employee was actually involved. Prevention of human accidents is, one of the essentials in cutting operation costs, and advocates of safety are studying economics to assist them in their work of preventing accidents.Workman's compensation insurance or compensation for human accidents is a true operating cost, and is the only purely tangible measure available which gives a measurement of the cost of accidents even though, as will be pointed out later, it represents but a portion of the total cost of human accidents.In using premiums paid for compensation insurance as a measure of the cost of accidents, it must be kept in mind that most insurance laws, as pointed out in a former paper (Serial 2590 of the Bureau of Mines) provide a waiting period before compensation for the lost-time wages starts, with the compensation limited to definite percentages of the wages. The waiting period and limited compensation combined tend to limit the amount paid to an injured workman who, if he receives 1/3 of the lost-time wage, will probably have been reimbursed as high as the average injured workman.The total or complete economic cost of human accidents, must include, in addition to compensation paid for lost time, and the portion of the lost-time wage suffered by the workman for which he is not compensated, the additional cost to the company through-(a) temporary decreased production by the breaking down of the morale, etc., (b) the breaking in of a new employee which is admittedly expensive,(c) the increased liability of human and production accidents caused to or by the new employee.Another charge against accidents, which is not included in the compensation payment, is the economic loss through the killing of as workman who has no dependents. Few of the States' laws require any compensation except burial expenses to be paid for fatalities to persons having no dependents. It is estimated by the United States Bureau of Labor Statistics that the economic loss through a fatality is 6000 shifts. If each fatality was compensated for this amount of time and at half-time wages, using an average wage of $5.00 per shift, the compensation for fatality based on the economic loss would be $15,000. but the average actual compensation paid for each fatality is about $3,000."

Jul 1, 1924

By Manuel Gomez

Dehydrogenation factors, proximate analysis, and ultimate analysis were examined as predictors of the low-temperature -carbonization properties of coals varying in rank from lignite through anthracite. All factors studied contributed to reduction in variance of the sample populations investigated. Response surface regression models based on variables from proximate and ultimate analyses of coal were constructed for eight low-temperature carbonization assay product and gas component Fields. These models were tested with independent samples that included drill cores, sized fractions, petrographic fractions, and run-of-mine coal. The models developed were used to predict low-temperature carbonization yields or coals from major fields of Wyoming. This information was cast in the form of contour plots describing the potential low-temperature carbonization product yields of Wyoming coals and the properties of the resultant char or coke. The variables used as input v the models may be measured and collected during exploration; thus, the carbonization properties of a seam can be determined in advance of mining. The information presented in this report is useful in that it broadens the deciionmaking base for management when either mine locations or coal conversicl plant sites, or both, are being considered.

Jan 1, 1971

By T. E. Sterner

The Bureau of Mines investigated the use of a chromatographic gas analyzer in determining the concentration of combustion products in gas produced during field and laboratory thermal oil-recovery tests. Several parameters (carrier-gas flow, cell current, sample size, and temperature) known to affect quantitative analyses were studied using a commercially available dual-column, dual-detector chromatographic gas analyzer which had been modified to provide close control of these variables. The apparatus made possible a much closer control of air-and gas-injection rates and provided adequate data for performing material-balance calculations and for determining oxygen utilization during the laboratory and field combustion tests. The chromatographic analysis also aided materially in evaluating and measuring bypassing and gas travel times and in detecting high-permeability zones that were present in the reservoir.

Jan 1, 1965

By Alexander May

The U.S. Bureau of Mines conducted studies to determine if phosphate slag stockpiles at Tennessee Valley Authority's National Fertilizer Development Center were hazardous materials. The stockpiles were not hazardous materials as determined by Environmental Protection Agency (EPA) extraction procedure (EP) toxicity test. Radium-226 concentration was 28.7 pCi/g in slag and 2.1 pCi/g in background material. Radium-226 was not leached from the slag. Fluoride concentration was 3.87 pct in slag, 0.18 pct in subsurface material under slag, and 0.08 pct in the background. Slag material permeability was 1.65 x 10-3 cm/s, and subsurface material permeability was 3.24 x 10-6 cm/s. Rain water, trapped in a depression on top of the east slag stockpile, became seepage water at the base of the stockpile. Concentrations of EPA toxic elements in seepage water were much less than concentrations from an EPA EP toxicity test on the slag. Twelve elements-Na, Mg, Ca, Sr, Ba, Cr, Mn, Co, Cu, Cd, AI, and P-had higher concentrations in seepage water than in rain water on top of the slag stockpiles, or in creek water adjacent to stockpile bases, indicating that they were leached from slag stockpiles.

Jan 1, 1990

By Everett A. Sondreal

Data are presented on the characteristics of lignites with emphasis on the composition and fusion properties of the ash. Differences in the analyses of commercial-grade lignites are related primarily to variations in moisture and ash contents. Lignite ash is generally characterized by high concentra¬tions of alkaline earth oxides and a greater tendency for retention of sulfur in the ash than higher-rank coals. Composition of ash varies significantly within and between mines. The differences within mines are significant for short distances and may be eliminated under certain circumstances by normal mixing occurring during mining. The sulfur in lignite averages 0.6 percent and is found primarily in the organic or pyritic forms with only a trace of the sulfate. During the stan¬dard laboratory asking procedures, from 60 to 100 percent of the original sul¬fur is retained in the lignite ash. Trace elements, such as uranium and germanium, in the ash from commercial¬-grade lignites are present in low concentrations, but others, primarily copper and silver, are present in specific samples in concentrations approaching those found in some commercial ores.

Jan 1, 1968

By R. Blickensderfer

Test equipment that simulated frictional impacts between coal-cutter bits and mineral inclusions at a coal face during operation of a continuous coal mining machine was used by the Bureau of Mines in the laboratory to study the incendivity of impacts between various rocks, metals, and hard-metal alloys in an explosive mixture of air-7 pct natural gas. Quartzitic sandstone was found to be the most incendive of several rocks tested. Limestone concretions from a coal seam, known locally as "sulfur balls," sparked furiously but were not incendive. Among the metals tested, the type of steel used in commercial coal-cutter tools was the most incendive material tested. A l7-4PH stainless steel was less incendive and appears to be the most promising high-strength steel alloy, reasonably economical, for use in coal-cutter bits. Some hard-metal alloys, primarily titanium and zirconium diboride composites, were also evaluated as possible replacements for the conventional cobalt-bonded tungsten carbide used in the tip of coal-cutter bits. The metal-bonded diborides were generally less inc endive but more brittle than the conventional tungsten carbide. Carbonitride coatings on tool bits were also tested but found to have no advantage. The source of ignition during frictional impact between metal and rock was studied. Immediately after impact, a yellow flash was observed and a smear of metal near its melting point occurred on the rock. This hotspot on the rock, rather than the yellow flash or sparks or metal fragments, was observed to be the cause of the ignition.

Jan 1, 1974

By Manuel Gomez

The purpose of this study was to evaluate the feasibility of using statistical response surface regression analysis to predict the sulfur and ash distributions and the washability characteristics of coal along a seam in advance of mining. Prediction equations were developed with experimental data from channel, bench, and core samples from the Pittsburgh coal seam in Greene County, Pa. It was not possible, with the available experimental data, to construct mathematical models to predict ash and sulfur concentrations between sample points. In the authors' opinion, however, the good agreement between experimentally determined and predicted values at given sample points demonstrates the usefulness of the method. More input data, such as geologic information, seam characteristics (rock-to-coal ratio), petrographic analysis, and chemical data, would perhaps make it possible to predict sulfur and ash concentrations and washability characteristics between sample points.

Jan 1, 1970