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"One of the functions of the United States Bureau of Mines is to investigate the ability of electrical mining equipment to operate in a gassy mine without danger of igniting explosive atmospheres. To accomplish this purpose, tests are made in which mixtures of gas and air are ignited in the equipment while it is surrounded by explosive atmospheres of the same composition. In such tests, records of pressures developed by the internal ex-plosions are obtained and observations are made of any flames, sparks, or smoke which may issue from bearings and joints. Occasionally the explosion pressures in a mining machine rheostat or a compartment of some other machine reach a value which is judged to be excessive or abnormal.A number of factors are known to influence the explosion pressures, and both German and. British investigators have irate extensive research on their effects. Much of this work had been done with artificial compartment which certain conditions could c held, constant while others were being varied. The U. S. Bureau of Mines has not made any research on a scale to compare with that of the British or German investigators; however, special studies have been necessary from time to time to determine the cause and remedy for high pressures obtained in the routine test of some piece of mining machinery. Thus it has been possible to verify some of tee theories established on a purely experimental oasis by practical tests of machines as actually built for mine use.Some of the factors determined the pressure that will result when an explosive mixture in a compartment or connected compartment is ignited are: (1) The volume of explosive mixture ignited, (2) the percentage of as in the mixture, (3) the amount of coal-dust in the compartment or compartments, (4) the degree of movement or turbulence of the mixture at the time of ignition, (6) tightness of the joints and bearings, (6) the size of opening between, compartments, (7) the distance between the point of ignition and openings, and (8) the cooling, effect of surfaces and of material inclosed in the compartments."

Dec 1, 1929

By George H. Holmes

The water situation in Nevada mineral and related industries is described in this report. It contains information on the sources and adequacy of supply to current operators, requirements and uses, quality and costs, geography, hydrography, precipitation and evaporation characteristics, and Nevada water laws. Also, information is given on the water requirements of one public utility powerplant, and the source and consumption of water in four major cities. Water distribution at 24 operations is shown on schematic waterflow diagrams. The mineral industries of Nevada in 1962 used 8.6 billion gallons of nee' water and reused 3.8 billion gallons for a total usage of 12.4 billion gal¬lons. The copper industry was the major water user. The 1962 value of all mineral production in Nevada was $85.5 million. The large amount of water required to maintain this high production is obtained principally from ground-water sources in alluvial valleys and the permeable rock formations of some mountain ranges. Some water is also obtained from perennial streams and springs. Sources of water utilized by existing industry ore near most mineral industry operations; however, seven companies are forced to pipe water distances ranging from 2 to 8 miles. Although water supplies of presently operating companies are adequate at most operations, several companies resort to large-scale reuse of water as a matter of conservation and economics. Acquisition of water by new operators is possible but takes considerable negotiation. Water rights, surface and underground, are controlled by the State. The quality of the water is satisfactory for most purposes. Analyses of 19 samples, listed in the appendix, show the range in water quality at various plants throughout the State. Costs of delivering new water to current operations range from 2 to 26 cents per 1,000 gallons with an average of 10 cents per 1,000 gallons for power and maintenance. No firm costs for recirculating water were available; estimated costs range from 1.5 to 2.5 cents per 1,000 gallons. The mineral-product value of the entire Nevada mineral industry in 1962 was equivalent to $10 per 1,000 gallons of new water and $26 per 1,000 gallons consumed. Projection of the 1962 water requirements of the Nevada mineral industry indicates that the demand for new water will increase from 8.6 billion gallons in 1962 to 11.9 billion gallons in 1980, a 43-percent increase. Water requirements ill the year 2000 are estimated as 14.8 billion gallons, an increase over 1962 water demand of 78-percent.

Jan 1, 1966

Papers presented at a U.S. Bureau of Mines (USBM) technology transfer seminar describe the causes of violent material failure in U.S. mines, measurement techniques for monitoring events that result in violent failure, and mitigation techniques for controlling failure. Specific factors contributing to violent failure are identified on the basis of geotechnical monitoring in 16 U.S. hard-rock and coal mines and on statistical analyses of 172 coal bump events. New monitoring and analysis techniques developed as tools for assessing violent failure; geotomographic methods that provide new capabilities for the study of material failure and stress changes over large areas; and seismic methods for determining source locations, calculating energy release, and determining source mechanisms are described. Fair correlations have been established among seismic parameters, elastic stresses, face support load, and violent events. USBM studies have identified the advantages using both yielding and stable pillars for coal bump control. A computer program has been developed as an aid for selecting room-and-pillar layouts. The practical aspects of implementing a destressing program is outlined for coal mines, while the importance of mine orientation and timely support installation in controlling buckling-type failure is identified for hard-rock mines.

Jan 1, 1995

By Frank C. Townsend

Waste disposal schemes using spent shale in embankments require a thorough knowledge of its geotechnical engineering properties for environ-mentally safe disposal. In this context, the objective of this laboratory investigation was to determine the physical properties, geotechnical properties, and composition of spent oil shale retorted by the PARAHO and TOSCO processes. Physical properties consisted of mechanical analyses, Atterberg limits, and specific gravity determinations. Geotechnical engineering properties were determined by compaction, maximum-minimum density, unconfined compression, triaxial compression, permeability, direct shear, Ko, cyclic tri-axial, resonant column, and Los Angeles Abrasion tests. Petrographic, chemical, and scanning electron microscopy analyses were used to determine compositional features. Unprocessed shale is hard and durable and more properly described as a carbonate rock instead of shale. PARAHO is classified as a GP, while TOSCO classifies as an SM. PARAHO requires no moisture for compaction to maximum densities; however, TOSCO does. Retorting causes a loss in durability but creates self-cementing characteristics, which for PARAHO a 3-to 8-fold strength increase was observed, while for TOSCO the increase was 1.5 to 3 folds. The shear strength, compressibility, and dynamic properties of compacted PARAHO are comparable to those for sandy gravels. Compacted PARAHO is semipervious, while compacted TOSCO can be semipervious to impermeable.

Jan 1, 1979

By H. G. Iverson

Solid state reactions of manganese with silica were investigated in high-temperature tests. Reactions of 0.5 to 4.0 moles manganese (Mn) with 1 mole silica (SiO2) at 1,100° C and of 2.0 Mn:SiO2 mole-ratio mixtures at 1,000° to 1,150° C yielded products consisting of a slag phase and a metallic phase. At 1,100° C, the slag phase from reactions of the low Mn:SiO2 mole-ratio mixtures was composed of SiO2 and rhodonite (MnSiO3), and the slag phase from the high Mn:SiO2 mixtures was composed of MnSiOs and tephroite (Mn2SiO4). The metallic phase from the corresponding low Mn:SiO2 mole-ratio reactants consisted of two manganese silicides, Mn5Si3 and Mn3Si; from the high Mn:SiOg mixtures, it was Mn and the manganese silicide (Mn5Si). For the higher mole ratios of MnSiO2 the manganese content in the metallic phase increased, while the manganese and silica contents of the slag phase remained nearly constant. The slags did not contain free or uncombined manganese oxide (MuO). For the 2.5 to 4.0 Mn:SiO2 mole-ratio mixtures reacted at 1,100° C, the maximum quantities of silica reduced and of the manganese in the slag appeared to become asymptotical at about 41 and 48 percent, respectively. A brominating procedure was developed that was highly selective in removing the metallic constituents from the reaction product, leaving the slag phase as residue. X-ray diffraction patterns were obtained on prepared silicides Mn5Si, Mn3Si, and MnSi.

Jan 1, 1967

"Requests are frequently received by the Information Service of the Bureau of Mines for published information on the coals of different foreign countries, as compared with coals mined in the United States. The analyses of various coals from several countries on the Pacific, which were submitted to the Fuels Division for certain tests between the years 1913 and 1916, may be of interest, and are shown below: Results of Analyses of Various Coals from China, New Zealand, Japan and Australia."

Sep 1, 1925

By Herbert H. Einstein

Rock mass deformability is commonly predicted using correlations with RQD or other indices of rock mass quality, or by extrapolation from large in-situ tests. Based on the probabilistic description of rock masses empirically developed in Part I a new approach was attempted in modeling for predictions of deformability. This approach decomposes the rock mass into spatially variable joints described by probability distributions, and intact rock blocks. Stiffnesses and elastic parameters are associated with the joints and intact blocks respectively, and deformations built up by adding the contributions of each. This model allows relaxation of many of the simplistic geometric assumptions which constrain parallel attempts to model deformation in rock masses. The model has been applied to four standard cases in order to test its results against previously existing models, and to check whether it replicates empirical correlations. When joints are taken as parallel, common empirical correlations are closely approximated by the model output. However, the closeness to empirical correlation breaks down when variability of the jointing geometry is increased.

Jan 1, 1979

By H. B. Hill

The discovery of the Oklahoma City field and its .rapid development into one of the major oil-producing districts is an outstanding epoch in the history of the petroleum industry not only of .Oklahoma but also of the United States. The relatively great depth to which the wells were drilled and the large initial production of high-gravity oil are of special significance. The field has boon under proration almost from the time that its development began, and many new production problems have developed out of the changed conditions of operation. The discovery well was first tested in December 1928 at a depth of 6,402 feet, with an initial production of 4,847 barrels of 38.5° A.P.I. gravity and several months later was completed at a depth of 6,624 feet. The large initial production, the high pressure, and the large gas volume in the different horizons of the discovery well suggested the potential possibilities of gas and oil, production in formations of Pennsylvanian and pre-Pennsylvanian age.

Jan 1, 1933

Mine drainage and mine reclamation are topics of major interest to the mining industry, federal and local governments, and the general public. This publication and its companion three volumes are the proceedings of a conference held in Pittsburgh, Pennsylvania, April 24-29, 1994. There were twelve sessions (69 papers) that dealt with mine drainage, including modeling, geochemistry, prediction, treatment, control strategies, characterization, hydrology, and case studies. These sessions comprise volumes 1 and 2. The six sessions (34 papers) that dealt with reclamation and revegetation of disturbed lands are included in volume 3. Volume 4 includes the six sessions (34 papers) that dealt with such topical issues as fires at abandoned mine sites, subsidence, hydrology, mine wastes, and policy. Poster session presentations are represented by 49 papers and 92 abstracts that have been placed in the back of volumes 2, 3, and 4, consistent with the subject of that volume.

Jan 1, 1994

By Frank E. Cash

The compensation-insurance rates for quarrying in North Carolina are 11 times higher than for the State?s major industry, textiles. Some operators are willing to accept this as representing the ratio of existing hazards. This was not true of the management of the Southern Aggregates Corporation, and in 1935 it tools definite steps to correct the idea of its local officials and employees that loss of life and limb in quarries is inevitable. ACKNOWLEDGMENTS The authors acknowledge gratefully the assistance and information concerning these operations furnished by H. M. Shaw, safety director (also secretary and treasurer), Southern Aggregates Corporation, Raleigh, N. C.; by the following superintendents: J. H. Rodgers, Blair Quarry, Blair, S. C.; J. D. Lane, Greystone and Rolesville Quarries, Henderson, N. C. ; J. H. Arthur, Guilquarry, Stokesdale, N. C.; J. H. Watkins, Rockton Quarry, Wendell, N. C.; P. A. Wellenborne, Reidsville Quarry, Reidsville, N. C.; and J. L. Kirchin, Woodleaf Quarry, Woodleaf, N. C.; by the various foremen at the plants, and by Murry Id. Grier, safety engineer, North Carolina Department of Labor, Asheville, N. C.

Jan 1, 1940

By Maria I. De Rosa

The U.S. Bureau of Mines conducted a study to determine if correlations exist between the chlorine or nitrogen contents of materials and the hydrogen chloride (HCI) or hydrogen cyanide (HCN) concentrations evolved during the thermal decomposition of these materials. Hydrogen chloride, hydrogen cyanide, and carbon monoxide (CO) were found to be the primary toxic gases evolved during the combustion process. The experiments were carried out in a 20-L furnace with 1-g samples. The furnace temperature, rising from ambient, was set at 1,000 °C with an airflow of 10 L/min. The variables measured were the gas loads (milligrams per gram) of HCI, HCN, CO, and CO2 (carbon dioxide); CO and CO2 concentrations as a function of time were also measured. Other variables included the average concentrations of submicrometer smoke particles and particles' average diameter, mass of particulates, sample and furnace temperatures, and sample weight loss. The data indicate that there are significant correlations between the percentage of chlorine or nitrogen contained in the original samples and the HC1 or HCN concentrations evolved during the combustion of the materials. These correlations may be used to predict and evaluate a material's toxic hazard during combustion.

Jan 1, 2010

By P. R. Tisot

This report discusses the waxes made from shale-oil wax distillate, a specific fraction obtained- from crude shale oil. The plate wax crystals Were exceptionally well suited to solvent extraction. Methyl ethyl ketone was the preferred dewaxing solvent.' The quantity of wax recovered at 32°F was 18.8 percent of the wax distillate, or 6.6 percent of the crude shale oil. The laboratory batch processes used for separating the wax from the distillate and subsequent refining were based .upon conventional petroleum methods. Three grades of shale-oil waxes were made and designated as crude, semirefined, and fully refined. The solvent-extracted wax consisted mainly of paraffin and olefin hydrocarbons. The physical Properties of the fully refined shale-oil wax were the same as er corresponded closely to those of Billy refined petroleum paraffin wax. Inasmuch as the crude and semirefined shale-oil waxes can be separated and refined in much the same manner as petroleum waxes, the cest of manufacture should be about equal to that for making petroleum paraffin wax. The cast of making a fully refined shale oil wax will be somewhat greater than for making .a fully refined petroleum paraffin, due to the loss of the oleofinic material from the shale-oil wax by acid treatment and the increased quantity of acid required for its removal. An analytical method for the determination of wax in shale-oil dietillates, a list of the physical properties that wore determined for the waxes, and the method for testing those properties are given in the appendix to this report

Jan 1, 1950

By R. F. Droullard

The Bureau of Mines has used gross alpha and gross beta detectors to continuously measure radiation working levels for a number of years. During this time, improvements have been made in the design and performance of continuous working-level (CWL) detectors. This report discusses the improved designs and some of the operating principles and applications of CWL detectors in the measurement of radon daughter products in mines and dwellings.

Jan 1, 1985

By James C. Church

The Bureau of Mines devised and demonstrated a portable linear cutting tester that directly measures and records the in situ cutting forces required of continuous-mining machine picks to it coal in underground mines. It requires only two operators to transport and operate the tester, which can be assembled and operated through a complete test cycle within a single mine work shift. This report reviews the factors considered in the design and development of the tester and the results of its system verification testing at coal mine sites.

Jan 1, 1985

By J. S. McNabb

"A search for manganese ore by core-drill exploration was carried out by the Bureau of Mines in the Philipsburg mining district in Granite County, Mont., in 1939 and 1940. This work was based on detailed studies of the manganese ore bodies of the district previously made by the Geological Survey.In 1949 further search for manganese in the district was deemed advisable. Diamond drilling was begun the following year as a joint program by the Geological Survey and the Bureau of Mines with the primary purposes of probing ore-leasing structures and extending the limits of known ore bodies. A secondary objective was to test a geologic theory based on a new conception of manganese-ore localization. The exploration targets were designated and the drilling results interpreted by the Geological Survey, and the Bureau of Mines was responsible for the drilling, sampling, and core handling. Improved drilling equipment and methods were utilized in an effort to obtain better core recoveries than resulted from the earlier drilling campaign.The Philipsburg mining district, Granite County, Mont., is 27 miles south of Drurrnnond, about 45 miles airline northwest of Butte, and 1 mile east of Philipsburg. During the course of the investigation patented lode-mining claims owned by the American Machine & Metals, Inc., the Contact Mines, Inc., and the Moorlight Mining Co. were diamond drilled.The district has been an important source of domestic manganese dioxide ore since local recognition of the mineral's importance during World War I. Peak annual output in 1918 of about 127,000 tons of manganese ore was utilized principally by the steel industry. A small but relatively steady output has persisted to the present to satisfy demands by battery manufacturers for battery-grade manganese dioxide.The known manganese deposits of the district are in sedimentary rocks of Paleozoic age. These rocks lie along a north-trending anticline traversed by a series of east-west tension veins. The east flank of the anticline terminates at a steep-dipping fault contact against a small granodiorite batholith.Replacement deposits of manganese oxides and carbonates occur locally in or closely associated with tension veins cutting calcareous rocks, or adjacent to the intrusive. Rhodochrosite has been a common accessory mineral in deposits valuable chiefly for lead, zinc, and silver. Some of the replacement deposits characteristically are irr2gular in outline, whereas others have fairly regular walls marking the limits of favorable beds."

Dec 1, 1955

By W. W. Adams

The year 1937 was signalized by increased employment in the metal-and nonmetal-mining 4 industry of the United States. Measured by the number of men working, there was a 17-percent gain in employment compared with 1936. In total number of man-hours worked at all mines, the gain was slightly over 18 percent. Hazards connected with mining resulted in more accidents to the workers than in 1936, but the increase in number of accidents caused only a slight rise in the accident rate because of the much larger increase in the number of man-hours worked. In fact, the fatality rate per million man-hours of exposure was lower in 1937 than in 1936, but the rate for nonfatal injuries increased slightly.

Jan 1, 1940

By David J. Kusler

The Bureau of Mines reviewed current technology in the refractories consuming industries and evaluated the impact of changes in technology on the supply and demand of refractories. Literature was searched and contacts were made with leading consumers and producers of refractories. The distribution of refractories by value of shipments to users was surveyed. The report shows that the percentage distribution of refractories sales to the consuming industries has remained essentially constant during the last decade but that substantial changes have occurred in the relative distribution of types of refractories. The trend in pyroprocessing technology in recent years has been toward higher temperatures, which require more costly refractories. This fact is reflected in the impressive gain in the dollar value of refractories sales, which in 1968 was about one-third greater than in 1960, and the rapid growth of refractories based on high-alumina, magnesia, zirconia, carbon, and other materials, at the expense of fire clay, silica, and chrome- based refractories. An appendix to the report contains refractories value and shipment data tabulated in a manner by which trends in the distribution of refractory types can be observed from 1955 to 1968. In addition, unit values are presented on a per-ton basis for comparison.

Jan 1, 1970

By George Quackenbos

The principal objective of this Program is the design, fabrication and testing of an Environmental System for operation in underground mines, to assess the effect of various mining systems on the contaminant levels near the mine face and within return airways. In order to determine the effect on airborne contamination in mines resulting from the development of new mining techniques, equipment and control systems, a Comprehensive Monitoring System is required to assess such contamination levels at critical and strategic locations and relate this information with ventilation parameters. The three variables to be sensed on a continuous basis are airborne dust concentration, methane concentration and ventilation air velocity. Each Monitoring Station will consist of a self-contained unit containing a power source and sensors to monitor the three above mentioned parameters. Ruggedness, reliability, ease 'of operation and intrinsic safety are important design objectives. Data gathered by each Monitoring Station will be fed to a Central Data Acquisition System by means of a portable transfer unit.

Jan 1, 1982

By R. A. Egen

The purpose of this book is to provide an indication of what good hoisting practice is and how it might be achieved. To this end the book contains discussions of equipment and inspection and maintenance procedures developed and used by mining people in striving for safe, reliable hoisting equipment. Most of this information comes from domestic practice; the rest is foreign, notably from Canada. Most things discussed have long proved their general worth, and others promise to; a few are beginnings. However, nothing is conjectural or theoretical; the practices described herein are in use somewhere in the mining world. The stress is on equipment in use; it is not a design-guidelines manual. Nevertheless, there are some sections dealing with design material since it may be of value in a maintenance/ replacement sense. Mine hoisting installations encompass such a wide variety of equipment and conditions that it is impractical to specifically cover them all. This book mainly treats conventional systems using conventional components with some discussion of the more common unconventional (special) systems in use. There is no recognized definition for a "conventional" mine-hoisting system. Herein the term means those systems most commonly used in daily operations for transporting men, materials, and product-electrically driven drum and friction hoists, with guided conveyances running in vertical or inclined shafts. Beyond this, what "conventional" means is probably best illustrated by the topics discussed.

Jan 1, 1975

By Richard L. Sanford

This report summarizes the results of the development of a Directory of Computer Programs Applicable to U.S. Mining Practices and Problems. The Directory includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various U.S. government agencies. References to computer applications throughout the mining industry are presented as well as comments on the availability of programs to interested organizations or individuals.

Jan 1, 1977