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By L. C. IlsLey

The service given by a flame safety lame is twofold: It provides a safe light and it gives evidence of the condition of the mine atmosphere relative to the presence of methane and the deficiency of oxygen. Since the development of portable electric mine lamps, flame safety lamps are little used for lighting,but their use as detectors is as extensive and important as ever. A flame safety lamp in the hands of a trained user will definitely how methane concentrations as low as 1 percent, which in well below the lower explosive limit of methane and air. However, this does not always suffice, especially when making studies of mine ventilation, where it may be desireable to detect concentrations below 1/2 of 1 percent.

Jan 1, 1936

By L. C. IlsLey

[The service given by a flame safety lame is twofold: It provides a safe light and it gives evidence of the condition of the mine atmosphere relative to the presence of methane and the deficiency of oxygen. Since the development of portable electric mine lamps, flame safety lamps are little used for lighting but their use as detectors is as extensive and important as ever. A flame safety lamp in the hands of a trained user will definitely show methane concentrations as low as 1 percent, which in well below the lower explosive limit of methane and air. However, this does not always suffice, especially when making studies of mine ventilation, where it may be desireable to detect concentrations below 1/2 of 1 percent.]

Jan 1, 1936

By George C. Branner

This study was planned to present salient facts of the California and Nevada sulfur industries and to indicate existing opportunities for increased economic utilization of California and Nevada sulfur resources. Numerous publications on sulfur have been issued by the Federal Bureau of Mines, including Information Circular 6329, Sulfur, by Robert H. Ridgway (1930); annual Minerals Yearbook chapters on Sulfur and Pyrites, by various authors; and a chapter on Sulfur by G. W. Josephson in Bureau of Mines Bulletin 556, Mineral Pacts and Problems (1956). This literature, however, deals primarily with the national and international sulfur situation and does not attempt to analyze the possibilities for increased economic development of sulfur resources by individual States. The present study attempts to analyze these possibilities in California and Nevada and to (1) evaluate factors that have influenced production and consumption in California and Nevada and (2) indicate apparent trends in production, consumption, and prices in these States.

Jan 1, 1959

To suppress the natural bacterial action in acid mine drainage (AMD), the major contributor to acid formation. Approach Recycle partially-treated affluent back to the source of AMD within a mine, or to the coal or coal-waste stockpile. This effectively eliminates any further biologically-promoted AMD by inhibiting catalyzed weathering or oxidation by acid-forming bacteria. How it Works AMO-type effluents can be largely reduced by "recycling" the acidic outflow back to the source of AMD within a mine or to the Input side of a waste pile to percolate through the reactive pyrite and bacteria mixture. The bacteria in the cell thrive on the oxidation of ferrous to ferric iron through the electron transfer, Fe2 +[=]Fe3 + + e. Its reaction product [s, therefore, essentially ferric iron. While small quantities of Fe3 + will not interfere with the exponential multiplication of the bacteria

Jan 1, 1982

By Todd M. Ruff

An average of 13 mine workers are killed each year by being run over or pinned by mobile mining equipment. At surface mines, these accidents commonly involve large dump trucks that drive over a smaller vehicle or a person that is in the dump truck’s blind spot. One method of detecting a person or another vehicle in a blind spot is to use some type of sensor technology such as radar or radio-frequency identification (RFID). Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health tested a number of commercially available and experimental sensors that monitor obstacles in a vehicle’s blind spots. None of the sensors had been previously applied to the specific problem of rigid-frame surface mining trucks. This report documents the procedures and results of tests conducted after RFID and radar systems were mounted on a 50-ton-capacity dump truck. It was determined that both RFID and radar technology show promise for detecting obstacles in the blind spots of mining equipment; however, more development work is needed to meet the unique requirements of mining equipment and the mine environment.

Jan 1, 2000

By A. J. Kraemer

This report on the physical and chemical properties of crude oils of California is one of a series on the producing districts of the United States. It includes a short discussion of results, tabulated data, and individual analyses of California crudes. Analyses of crude oils from the fields of Fresno, Kern, Los Angeles, Orange, and Ventura Counties have been published in Serials 25952 and 26083. The analyses reported in this paper corer samples that were obtained subsequent to the publication of Serials 2535 and 2608. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of samples was facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1927

By R. E. Simpson

Beginning in 1972, fully grouted resin bolts were used in underground mines. An estimated 20 million resin bolts will be installed in 1980 owing to their apparent support improvement in most roof-bolt applications. Inorganic cements were tested to replace the resin at a lower cost while retaining the advantages of a grouted bolt. Although other inorganic materials were considered, all but portland and gypsum cements were rejected for reasons of availability, performance, or cost. Portland and gypsum-type cements were tested by the Bureau of Mines to select a fast-hardening, low-cost material that would anchor a roof bolt adequately to meet safety standards. An alpha-gypsum cement, accelerated with potassium sulfate, was selected as the best material because it had adequate pull strength at a desired set time of less than 5 minutes and was readily available.

Jan 1, 1980

By John R. Benham

In 1979 and 1980, the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral survey of the 20,500 acre Black Butte RARE II area (No. 5102) in the Los Padres National Forest (fig. 1). The work by the Bureau of Mines indicates that the potential tor mineral resources in the area is low. Samples of outcrops and stream channels contained no economic minerals. A mercury deposit near a granodiorite-sedimentary rock contact occurs 2 mi northeast of the study area, but similar deposits have not been discovered within the area. Geothermal potential exists near Tassajara Hot Springs, but no thermal springs occur in the area; nor have oil, gas, or coal resources been found.

Jan 1, 1982

By R. V. Ramani

This report is volume 10 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report describes the Ventilation subsystem of the Master Design Simulator. The Ventilation subsystem has the capabilities to handle: (1) branches in parallel or series, (2) fans in parallel or series, (3) multiple fans, (4) methane, compressed air, or other injections into the system, (5) leakages and fixed quantities, and (6) calculations of absolute pressure at nodes. The program uses the Kirchoff's Junction and mesh laws, and the Hardy-Cross iterative technique to converge to the desired accuracy in solving fox the head quantity. A case study is included in the report illustrating the use of the model. The appendices of the report constitute a user's manual for the Ventilation subsystem, and include a program listing.

Jan 1, 1975

By R. J. Gunderman

A conventional trailing cable connection box on a continuous mining machine was modified by the addition of two innovative devices. These are a pressure vent to preclude buildup of high pressure due to an explosion in-side the enclosure, and a grommet-type cable entry to simplify and speedup cable entering procedures. The innovative devices were evaluated for eight and one-half months in a working section of an underground coal mine. Laboratory tests before and after the in-mine exposure show no measurable change in the devices. Following the favorable in-mine evaluation, technical performance criteria were defined to serve as the basis of approval for the use of the innovative devices. Additional tests to measure comparable gripping of the cable by asbestos rope, substitution rope materials and by the urethane grommet-type entry were included in this effort. Also, literature for the last 80 years was searched. Comments are provided as to how the innovative devices comply with 30 CFR Part 18.

Jan 1, 1982

By Charles T. Baroch

RESEARCH strengthened the position of cesium as the preferred material (commonly but erroneously called "fuel") for ionic propulsion engines. Its use as an element of the plasma thermocouple for generating electricity also seemed more likely. Domestic Production.-No domestic ore of cesium and rubidium was produced. San Antonio Chemicals, Inc., San Antonio, Tex., and Maywood Chemical Works, Maywood, N.J., continued to produce cesium and rubidium compounds including carbonate, chromate, hydroxide, nitrate, sulfate, and all four halides. Rocky Mountain Research, Inc., Denver, Colo., began producing various cesium and rubidium salts. American Potash & Chemical Corp., Los Angeles, Calif., offered cesium and rubidium for sale.

Jan 1, 1960

By J. L. Holman

The Bureau of Mines, at its Rolla Metallurgy Research Center, has devised methods for separating and reusing the major portion of waste plastics discarded in urban and industrial refuse. Waste plastic concentrates from a local collection drive, recycling center collections, urban refuse pilot plants, and the secondary metals industry were separated into three major thermoplastic families--polyolefins, styrenes, and vinyls--based on differences in density using a Bureau-designed sink-float-elutriation hydraulic separator. Other separation methods and systems such as air classification, jigging, liquid media, screening, and electrostatics were studied. Vinyl plastics contain up to 50 percent HC1. It was found that over 90 percent of the HC1 in vinyls can be recovered as usable hydrochloric acid by pyrolysis at 350° C. The remaining pyrolysis products which had heats of combustion in excess of 12,000 Btu/lb, could become valuable as a future source of energy. A characterization study conducted on eight chopped wire insulation wastes from secondary copper and aluminum processors showed that most wastes contained 2 to 7 percent residual metal and large percentages of vinyl. The residual metal content of some of these wastes was lowered to 0.1 percent and the vinyl portion segregated using various separation techniques. The research also suggests ways in which reclaimed thermoplastics may be fabricated into useful products.

Jan 1, 1974

By K. L. Paciorek

The aim of the present study is to determine on a gram per gram basis the toxic products of the thermal oxidative degradations of selected compositions. Four families of materials were investigated under the subject contract namely polyvinyl chloride and neoprene compositions, rigid urethane foams I and woods. Three methods were employed to conduct the thermal oxidative degradations: a sealed system (quiescent environment) I a stagnation burner arrangement (dynamic environment) I and a flow-through apparatus (dynamic I but less severe than stagnation burner conditions). The majority of tests were conducted using the first two systems; only limited experiments were carried out employing the third decomposition procedure. All decomposition was done at temperatures of 370 -4000C I the higher temperature being used in the stagnation burner. It has to be stressed that the nature of the products and the relative product concentration are temperature dependent. Thermogravimetric and differential thermal analyses were performed to supplement and extend the above delineated studies and to explore the feasibility of using these analyses as a method for material differentiation.

Jan 1, 1973

By James Westfield

Following is a brief resume of the Division's activities that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code for Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous-coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reporting to the Coal Mines Administrator any violations of the Federal Mine Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority under Executive Order 9728 was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1961

By Walter E. Pittman

This Bureau of Mines study surveys the current state of technology and the various research efforts that have been undertaken to dewater the dilute phosphatic clays generated in the production of phosphate rock. The research described includes early dewatering experiments, fundamental studies of clays and of flocculation, and minor dewatering techniques such as freeze-thaw methods, the ANDCO process, moving screens, sand wick, crust development, and overburden pumping. Some methods that are currently being evaluated are described. They include the Estech sand-clay mix process using the Enviro-Clear thickener, sand-clay sandwiching, dredge mix, dredge process, and the sand-spray process. Developing technology for dewatering phosphatic clays also is described, including the Bureau of Mines rotary trommel method and the Gardinier process.

Jan 1, 1984

To develop effective noise controls for continuous min-ing machines (CMMs) to reduce worker noise exposure. Background Noise-induced hearing loss (NIHL) is an occupational illness caused by chronic exposure to excessive sound levels. For underground coal mine workers, NIHL continues to be a serious health issue. Analysis of hearing loss data suggests that by retirement age, 70%?90% of U.S. coal mine workers will have a hearing impairment. Operated in the confined spaces of underground mines, large industrial mining equipment often produces sound levels that can be harmful to workers. Of all equipment used in underground coal mining operations, CMMs account for the most noise overexposures. To reduce the occurrence of noise over-exposures, engineering noise controls must be developed for the CMM.

Sep 1, 2008

By John A. Davis, John Gross

This paper is one of a series giving the results of metallurgical tests conducted by: the Alaska station of the Federal Bureau of Iſines, on the recovery of gold from the black sands of placer clean-ups. The data given in this report were obtained from tests on a lot of black sand from a property located on St. Patrick Creek, Fairbanks mining district, Territory of Alaska. This property comprises the Sagan Fraction and adjoining bench claims, and is being operated by J. A. Lillie. The sand ad already been treated at the mine by amalgamation. A sample taken by Mr. Lillie and assayed at the station showed that the gold still remain ing amounted to ll cents per pound. As this gold content was sufficiently high to justify further treatment of the same, 770 pounds were shipped to the station for testing. The reader will note that the gold content is given in cents per pouni, rather than per ton. This is in conformity with practice in the district in valuing black sands, as the quantity obtained at any one time is small, much less than one ton. . The sand consisted principally of schist and quartz, with very little ilmenite and garnet; and no magnetite or sulphides. Most of the gold present as contaminated with quartz, as the free particles of gold had been removed by amalgamation at the mine.

Sep 1, 1920

By Orlando Martino

This regional report covers the mineral industries of Canada and 40 countries and territories in Latin America and the Caribbean Basin. Also included is a brief description of the mineral potential of Antarctica. The Latin American region encompasses an area twice that of the United States. Latin America and Canada have a rich and diversified endowment of mineral fuels, metals, and industrial minerals. Tables 1 and 2 provide a summary view of Latin America and Canada's output of its major mineral commodities in world mineral supply in 1991 (revised) and 1992. Table 3 shows the relative importance of a selected group of minerals produced in Latin America in the world mineral economy.

Jan 1, 1994

By R. E. Kennedy

"INTRODUCTION In a previous publication4 results were given of numerous experiments made on the in-flammability of gas mixtures consisting of methane, hydro a. carbon monoxide, nitrogen, and carbon dioxide. Data were obtained and tables prepared giving the inflammable limits of each of these combustibles when mixed with various proportions of carbon dioxide and nitrogen. By the use of these data and the application of Le Chatelier's law, it was found possible to calculate the limits of inflammability of any gas mixture containing any or all of the above gases.Various mixtures of the five gases given above were prepared and their limits determined experimentally and then calculated. Good agreement was found between the determined and calculated results when complex gases encountered in mine safety work were tested. Of special significance was the accurate calculation of the limits of inflammability of gases from mine fires, gases from mine explosions, detonation products of explosives, blast—furnace gases, automobile exhaust gas, and other gases of a similar character.Using the method given in the above report, Yeaw5 investigated a number of industrial gases including oven, coal, producer, blue, carbureted blue, and dry quencher gases, and found the determined and calculated results to agree remarkably well, thus giving further proof of the value of such a means of determining dangerous conditions when combustible gases are encountered in practice.GASES FROM A POTASH MINEGases were recently encountered in a potash nine in New Mexico, containing the com-bustibles, methane, hydrogen, and ethane. In one special case a mild explosion occurred when these gases were mixed with the right proportions of air and ignited it therefore became necessary to know the inflammability of these mixtures in order that the proper precautions could be taken to prevent explosions."

May 1, 1932

By Nikolaos Polysos, Holger Witthaus

INTRODUCTION The classification system for German coal mining is the result of approximately 100 years of experience in roadway development and longwall mining. It is also based on different research projects covered by national and European research programs. Over the past 30 years, more then 600,000 m of road-ways have been driven and employed for mining activities. To properly describe the German rock mass classification system, therefore, it is useful to take a look at the main geomechanical preferences and common support systems. The decision about the most effective development technique and support system is based on a synthesis of rock mass classification and geomechanical analysis. The properties of surrounding rock, the in situ stress, and the influence of mining activities in several seams at each German mine must be considered for the evaluation of the expected deformation of the roadway. The mine layout, the requirements of ventilation and fire prevention, as well as the need to maintain emergency escape routes for the miners, require that the gate roads remain usable after the passage of the longwall face in most cases. Moreover, the gate roads must be maintained despite the high stresses that are applied during longwall retreat mining. Therefore, gate road design must address a broad spectrum of potential deformation environments. In the past, when gate roads were supported solely with yielding steel arches, lithologic descriptions of the surrounding strata conditions were adequate for the dimensioning of support and the prediction of the roadway deformation. The current conditions of multiple-seam mining at depths of up to 1,700 m require combined support systems, including pattern bolting and backfilled steel arches. Rock bolt support is used for development, after which (typically 50–100 m outby the face) the steel arches are installed and backfilled with building material (concrete) in order to achieve an optimized development rate. The rock mass classification system described below was developed especially for the conditions of German hard-coal mining. It includes the stress distribution caused by multiseam workings (including crossing goaf edges of former longwalls), as well as in situ stresses due to greatdepth and the presence of tectonic faults. It is based on the evaluation of four parameters: • Geotechnical analysis of drill cores • Geotechnical observation of the development face • Geotechnical classification of tectonic structures (faults) • Standard classification derived from geotechnical assessment and evaluation of stress conditions (using numerical modeling for stress calculation) ROCK STRENGTH One of the most important input parameters for describing strata conditions is the strength of the rock. The German classification system is based on a description of lithotypes. This method has been used successfully since the 1950s and is based mainly on the uniaxial compressive strength (UCS) of the material. An evaluation of the rock strength observed in a survey of approximately 82,500 samples of rock core yielded the results shown in Figure 1. The three most common coal measure rock types are mudstone, siltstone, and sandstone. Each shows a specific mean UCS level and a different spread between the minimum and maximum values. Sandstones, in particular, have a wide spectrum of compressive strength, ranging from approximately 40 MPa to greater than 130 MPa, with an average of 85 MPa. The causes of this wide range include different sedimento-logical preconditions, facies, and digenetic processes. [ ]

Jan 5, 2007