Search Documents

Provide an inexpensive, remote actuated, stench-gas system which reduces fire warning time to underground work locations. Approach A mine's pager phone hard-wire network is used to release stench gas from pressurized canisters located near working areas. The release is initiated by placing a coded message into a control phone at some central location. How It Works Currently, in most mines, the decision to release a warning stench gas is made by mine management after communication from the mine of a fire or similar potentially dangerous situation. Stench gas is then released into the ventilation air and/or compressed air lines for dissemination throughout the mine. This can result in significant delays in warning time. Often, surface personnel must travel to distant shafts, or other release points, wasting valuable time. Also, the time for ventilation air to circulate from the surface to working locations can be long and the effectiveness of compressed air as a stench transport agent depends on whether the compressed air is being used at the face. The Bureau of Mines, through a contract with MSA Research Corporation, has designed and tested a warning system which avoids these problems. The system consists of multiple, pressurized stench-gas canisters located under-ground in the mine-ventilation network so as to provide quick dissemination of the released stench gas to working areas. Each stench-gas canister is hard-wire connected to a nearby pager phone and from there to a control phone at the surface or at a central in-mine site. In the event of a mine emergency, the canisters are activitated to release stench gas by placing a coded message into the control phone. A low amperage Signal sent from the control phone to the receiver phone closes a relay, which activates a release mechanism on the canister.

Jan 1, 1984

By Kevin Connor

The mineral industry continued to be an almost negligible contributor to the country's economy as the Government continued its 1979 ban on any mineral exploitation for export; a policy initiated at the end of 1979. A national program had been underway since that time to map and inventory all mineral resources so as to permit future exploitation of mineral wealth in the beat interests of the country and its inhabitants. In March 1982, the British Sulphur Corp. Ltd., under contract to the Burundi Government and the International Bank for Reconstruction and Development (World Bank), began a feasibility study of Burundi's phosphate deposits at Matongo-Bandaga for potential commercial exploitation. The 1-year project effort was to define ore reserves, conceptually design mining operations and processing facilities, estimate capital and production cost, and develop a regional market and distribution survey. Work completed during the year comprised geological exploration and reconnaissance and 1,200 meters of core drilling. Reserves in excess of 5 million tons of ore-grade phosphate were estimated available for mining. Rare earth mineralization was associated with the primary apatite. The associated carbonatite within the rock matrix was preliminarily assessed to be of value as a raw material for the manufacture of cement. The contract effort was valued at $1.2 million? Matongo-Bandaga is located approximately 40 kilometers north of the capital city of Bujumbura and alongside one of the country's few paved roads.

Jan 1, 1984

By John C. Edwards

A two-dimensional, time-dependent, mathematical model has been developed that describes fire spread along the walls of a ventilated duct. The model is based on the assumption that the leading edge of the fire zone propagating along the wall surface coincides with the isotherm for the fuel ignition temperature. The model includes gas-phase energy transport via radiation and forced convection inside the duct and solid-phase energy transport by conduction into the fuel lining. Product gases emitted from the fire zone are assumed to mix uniformly with the ventilation gas to produce an optically dense gas mixture at the combustion temperature that enters the preheat region. Numerical solutions of the model equations for a coal-lined duct (simulated coal mine entry) have been used to investigate the effects of tube radius, air velocity, combustion temperature, and optical density of the soot-laden gas upon the terminal fire spread rate.

Jan 1, 1977

By Andrew B. Cecala, Edward D. Thimons

"The Bureau of Mines has recorded a number of different background dust sources that significantly contaminated the air breathed by bag machine operators. These background sources, observed at five different plants over the past 2 years, can expose bag machine operators to more significant dust concentrations than the filling process itself. To keep bag operator exposure within acceptable dust levels established by the Mine Safety and Health Administration, U.S. Department of Labor, the significance of these background sources must be realized, and the sources must be identified and controlled. The purpose of this work is to identify common background dust sources and show the significant effects that they have on the bag operator's overall dust exposure. INTRODUCTIONThe purpose of this report is to identify some common background dust sources in and around the bag-filling area. Although these background dust sources are of ten unrecognized, they can be more significant sources of contamination than the dust generated from the bagging process.The bagging of mineral products into 50- and 100-lb paper bags is common throughout the entire mineral processing industry. Bagging is performed by a bag operator who sits in front of a two- or four-station fill machine. The bagger's function is to attach empty bags to the fill nozzles as filled bags are ejected from the machine. If the product being bagged is extremely fine (smaller than 200 mesh), the bag operator's dust exposure is usually one of the highest in the plant.The bag operator is exposed to two primary dust sources. The first is product blowback during the bag-filling cycle. This occurs as excess pressure is released from around the fill nozzle during filling. As the excess air forces its way out of the bag, product is forced out with it. This blowback of product leaving the bag creates a considerable amount of dust. The second major source is the ""rooster tail"" of product thrown from the bag valve and fill nozzle as the bag is ejected from the fill machine. Since the bag is pressurized as it leaves the machine, product spews out of the valve for a few seconds."

Jan 1, 1986

By David P. Lindroth

The heat content above 25.0° C up to 1,000° C was measured for six rock types: St. Cloud Gray Granodiorite, Holston Limestone, Sioux Quartzite, Rockville Quartz Monzonite, Salem Limestone, and the basalt at Dresser, Wis. The calorimetric data were obtained with an isothermal jacket-copper block calorimeter. The experimental heat content data for each rock type are presented, along with specific heat data obtained from the temperature derivative of the heat content. For the six rock types the maximum deviations of the specific heats at a given temperature were within 10 percent below 575° C and within 34 percent above 5750°C. The increase in the values of specific heat range from a minimum of 13 percent for the basalt at Dresser, Wis. (temperature range, 100° to 1,000° C) to a maximum of 46 percent for Holston Limestone (temperature range, 100° to 870° C).

Jan 1, 1971

By F. N. Kissell

The Bureau of Mines used sulfur hexafluoride (SF6) tracer gas to evaluate the effectiveness of gob ventilation and/or sealing practices at three coal mines, each having different problems associated with their mined-out areas. The purpose of these ventilation studies was to better understand whether current techniques employed for ventilation or sealing are successful at minimizing the potential for gob fires and explosions. The work performed at each mine is discussed: One is a long-wall operation that uses ventilation to carry off hazardous gases, and two are room-and-pillar operations, each with far different concerns, that seal off the gobs to isolate them from the main mine ventilation. In all cases employment of the Bureau's SF6 tracer gas technique resulted in answers to questions raised by the mine operators concerning the effectiveness of their gob ventilation or sealing practices in preventing mine fires.

Jan 1, 1986

By Rose L. Ballard

This chapter summarizes data on crude non fuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are the tables that show the principal non fuel 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, 1986

By George H. Johnson

An evaluation of the diamond-bit-performance data accumulated from core-drilling cherty limestone and cherty dolomite reveals that the percentage of core recovered and the physical characteristics of the bits and diamonds used are economically significant. One of the established trends, of particular interest to those engaged in diamond drilling, is that bits set with small, low-quality, West African drill bort are the most economical. Detailed analysis of the factors that affect diamond-bit performances, such as diamond size and quality, bit size and type, percentage of core recovered, and the physical characteristics of the bit matrices are assessed in the tables, charts, and discussion.

Jan 1, 1958

By R. H. Nafziger

As part of its program to help decrease the dependency of the United States on foreign imports of nonfuel minerals and to devise technology for the efficient and economic use of domestic resources, the Bureau of Mines smelted and sulfation-leached an ilmenite from northern Minnesota. The objective was to assess the feasibility of preparing chlorination-grade titanium feedstock. The concentrate was smelted with woodchips, coke, and soda ash in 91-kg-and 1-metric ton (mt)-capacity electric arc furnaces to form Ti-rich slag and commercial-grade pig iron. The slag contained from 67 to 77 wt pct titanium oxides and from 1.8 to 7.2 wt pct iron. Sulfation occurred in a 4.5-kg/h moving-bed reactor using S02-air mixtures at temperatures of 8000 to 8500 C to form soluble salts of the Ca, Mg, Mn,and Na impurities, which cause plugging of fluidized-bed chlorinators. Subsequently, the sulfated slag was leached in acid to remove the soluble sulfates. The final product from small-scale testing contained up to 95.5 wt pct Ti02, a minimum of 0.6 wt pct Fe, and a minimum total of 0.3 wt pct of the four impurities of interest. The final product meets charge specifications for chlorination. However, more large-scale testing is necessary.

Jan 1, 1987

Several short color films describing new technology developed through Bureau of Mines research are available on a loan basis. The films review results of Bureau research programs aimed at aiding the minerals industry by increasing mine productivity, ensuring worker health and safety, and enhancing minerals recovery, processing and recycling. Most of the films are available in a choice of for mats: 16mm film, ½" VHS cassette tape, or ¾" U-matic tape. The films are loaned by the Bureau of Mines free of charge; borrowers are requested to pay only the return postage and for any damage to the films. All titles are also available for purchase in 16mm or videotape formats. Interested persons wishing to borrow or purchase a film should specify its title and the preferred and alternate showing dates. All requests should be addressed to: Motion Picture Library Bureau of Mines Cochrans Mill Road P.O. Box 18070 Pittsburgh, PA 15236 A short description of each film follows: Safer Coal Mining Equipment Traces the development of modified conventional and continuous mining equipment, beginning with an investigation of the problems encountered with mining equipment and continuing through long-term testing of the modified equipment in two mines. "Human engineered" coal mining machines are shown in operation. These machines include features such as adjustable cabs, easy access controls, improved illumination, and other safety improvements. (19 min)

Jan 1, 1986

By Ann G. Kim

Hydrocarbon gases, primarily methane but also the Ca through Cs paraffins, the Ca and C3 olefins and possibly the C4 and Cs olefins, are byproducts of coal formation. Although it is generally believed that coal formation occurred at temperatures below 200° C, most experimental work on gas formation from coal has been performed at temperatures between 200° and 1,000°C. The objective of this Bureau of Mines experiment was to determine if observable changes in the gases from coal could be produced at temperatures below 200° C in relatively short periods of time. The experiment involved heating coal samples from six coalbeds at constant temperatures and analyzing evolved gases. The composition of the gases at three temperatures was compared. At 35° C, over 99 pet of the gas is methane; at 125° and 150°, methane constitutes approximately half of the hydrocarbon gas. Isobutane and pentane are the predominant higher hydrocarbons at temperatures between 100° and 150° C.

Jan 1, 1974

By C. E. Jordan

The Bureau of Mines conducted laboratory studies on methods to increase the recovery of brine from slime produced by operating potash plants. The slime was comprised of 80 percent brine saturated with KCl and NaCl, and 20 percent solids. A variety of settling techniques, filtration methods, continuous centrifugation, and novel processing techniques were investigated. Vacuum filtration recovered 6S percent of the brine at 47 gallons of brine per square foot per day. Pressure filtration, on the other hand, recovered 74 percent of the brine at 40.9 gallons of brine per square foot per day. Centrifugation in a 6-inch-diameter continuous decanter-type separator resulted in 42 percent recovery of the brine at a treatment rate of 542 gallons of brine per day. Vertical drains proved to be the most promising novel debrining technique investigated. With this method, 45 percent of the brine was recovered in 3 days.

Jan 1, 1977

By Larry G. Stolarczyk

1.0 FRAMEWORK FOR COMPARISON This document describes the decision factors that bear on the selection of the modulation process for the wireless underground medium frequency (MF) communication system. The selected modulation process must satisfy the Bureau of Mines stated objective of improving general communications within an underground mine. The improvement being sought includes the development of a wireless communication technology of measurable benefit to both mine safety and mine productivity. The improvement will allow wireless communications paths to exist between roving miners. The wireless communication paths will also be made compatible with the existing underground telephone system to extend paging and voice communication throughout the underground mine. The new wireless equipment will include man-pack, vehicular, repeater, and base station transceivers. Repeaters and base stations will feature coupling networks for interfacing with the existing telephone circuits. Frequency modulation (FM) and single sideband (SSB) modulation processes are analyzed in view of the special conditions associated with underground mining. Of primary importance is the tremendous electrical noise generated in an operating mine that could adversely affect communications quality. High noise coupled with high attenuation rate of near field signals forces the communication system to be inherently short range. Fortunately, near field signals can propagate over great distances on underground wires and cables. The framework for comparison is generated by presenting all factors that

By P. W. Jeran, S. J. Pepperney, M. C. Irani, F. F. Kopsch

The Bureau of Mines has designed and put into operation a fail-safe control system for use in underground coal mines equipped with methane drainage pipelines. This control system can detect certain unsafe conditions and respond by automatically shutting off the flow of methane from the degasification borehole to the drainage pipeline. Methane flow is shut off when the methane content in the return airways reaches a predetermined level (typically 1.5 pct), when the methane drainage pipeline is ruptured by roof fall, or when there is an electric power failure. The fail-safe control system was designed using commercially available components and a methane analyzer system previously developed by the Bureau. The fail-safe system consists of a unit that combines a shutoff valve and pneumatic valve actuator, and electronic and mechanical equipment designed to detect hazards and effect shutdown. The fail-safe control system was designed to meet regulatory requirements issued by the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, and State regulatory bodies for the safe operation of underground methane pipelines used for mine degasification. MSHA has inspected and tested this system and permitted its use in two mines. The Bureau installed the fail-safe system in two working coal mines, where successful performance has been demonstrated.

Jan 1, 1980

By William G. Gruzenaky

The separation of yttrium and the individual rare-earth elements (lanthanons) from mixtures in which they occur has been a difficult problem through-out the years. Because of the increased interest in the various uses of these metals, the economy of their production may become of great importance. Studies relative to this problem, undertaken at the Federal Bureau of Mines Albany Metallurgy Research Center, resulted in the development of a solvent extraction method by which yttrium can be separated from the rare-earth metals. A separation factor of 10.93 was obtained between yttrium and cerium from a single-stage extraction, and a factor of 1.78 was obtained between yttrium and erbium from a multistage system. The valuable metals were extracted from euxenite by caustic soda fusion or by chlorination, and several separation methods were investigated. Partial separation of the yttrium and rare-earth element fraction was made by chemical methods and by solvent extraction. Thermal decomposition of aqueous rare-earth nitrates or selective ignition of yttrium and rare-earth oxalates yielded a fraction enriched in cerium. A fraction enriched in the light rare-earth elements resulted from a double sulfate precipitation, whereas a potassium ferrocyanide pr cipitation yielded a fraction enriched in yttrium. Precipitation with dimethyl phosphate yielded a fraction enriched in yttrium and heavy rare-earth elements. Enriched fractions were obtained with several solvent extraction systems. A system consisting of rare-earth nitrates, nitric acid, and tri-n-butylamine-3 methyl-2-butanone favored the separation of yttrium from the heavy as well as from the light rare-earth elements.

Jan 1, 1961

By Anthony T. Lannacchione, Donald G. Puglio

The Bureau of Mines developed data on the methane content of the Hartshorne coalbed, Haskell and Le Flore Counties, Okla. The methane content is calculated to be between 1.1 and 1.5 trillion cubic feet, based on an estimate of total coal in place of 2.4 to 3.2 billion short tons. Methane increases with depth, but the rate of increase decreases with greater depths. Degasification in advance of mining is recommended for all mines operating at depths greater than 500 feet to reduce hazards and methane explosions, decrease mine ventilation costs, and conserve the natural gas that would be otherwise wasted.

Jan 1, 1979

By Ronald D. Hill, Elmore C. Grim

The United States is richly endowed with mineral resources. However, mineral recovery by its very nature, involves a destructive process, Figures 1 and 2. In the past, mining practices were all too often conducted with the purpose of removing minerals by the simplest and cheapest method possible, without plans for the preservation of land, water, and air, and with too little consideration for the rights of others. A mining company is in business to make a profit, but every company, regardless of the nature of its business, has moral obligations to reduce its undesirable effects on the environment and to safeguard the rights of others. The problem of environmental degradation caused by surface mining is widespread and serious. Minerals in some form occur in each of the 50 States and several States are extensively mined. Data on the acreage disturbed in the United States, by commodity and State are presented in Table 1. Thirty-one States have laws regulating surface mining, (Table 2). Briefly reviewed in Appendix A-1 are the basic provisions of State laws governing surface mining. It can be seen that these laws vary considerably from State to State owing largely to the mining conditions within that State. Of the 24 coal-producing States, only three (Alaska, Arizona, and Utah) do not regulate strip mining. Even the states that are often cited as models of comprehensive regulations still have problems minimizing environmental damages. Uncontrolled surface mining presents a situation as critical to the well-being of the society as any it has ever faced. Many mining activities have imposed huge social costs on the public at large. These costs are long-range and are in the form of stream pollution, floods, landslides, loss of fish and wildlife habitats, unreclaimed land, erosion, and the impairment of natural beauty. In a 1965 Department of Interior study,(1)it was estimated that of the 25,000 miles (1+0,225 kilometers) of contour bench in Appalachia, approximately 1,700 miles (2735 kilometers) are affected by massive landslides. Additionally, 1+800 miles (7723 kilometers) of streams and 29,000 surface acres (11,716 hectares) of impoundments and reservoirs have been seriously affected by coal strip mining operations in the United States.

Jan 1, 1974

By L. C. IlsLey

Briefly, a permissible schedule of the Bureau of Mines establishes certain minimum standards for safety; it gives details of test methods adopted to determine whether these standards have been met, and a list of charges for such tests. Any manufacturer has the privilege of submitting his product for test in accordance with the conditions outlined in the schedules. His action is wholly voluntary, for the Federal Government has no jurisdiction as to what equipment shall be used in mines, this authority being left to the various States. When the product of a manufacturer has met the schedule requirements, he is permit¬ted to advertise this fact and to attach an approval plate with the bureau's seal to each machine he makes that is identical in every way with the equipment tested, inspected, and approved by the bureau. This work of approval has grown by the addition of new schedules until at present a great many mines are using one or more classes of permissible equipment, and there is still a demand for other approved apparatus in the ever-widening field of electrically operated machinery. The safety of electrical equipment of this type depends on four fundamentals, namely, (1) correct principles of design; (2) proper assembly of parts at the factory; (3) proper assembly and installation of equipment at the mine; (4) and proper operation and maintenance after installation. The first two factors are within the province of the manufacturer. The bureau either inspects and tests several models of one product, such as electric cap lamps, or one model, such as an electric motor. If this series of tests proves satisfactory, the manufacturer is given the privilege of making other appliances, and assembling them in the same way; the approval plate he attaches is his guaranty that the equipment is identical with the one tested and inspected by the bureau. The third and fourth factors concern those who use such permissible equipment, and it is to them that this paper is mainly addressed, in an effort

Jan 1, 1922

By Elizabeth A. Johnson

The effect of slag composition on lead losses to slags and on the behavior of associated accessory elements in lead blast furnace smelting has been studied by the Bureau of Mines. Equilibrations of 30 g of lead and synthetic slag doped with Cu, In, TI, and Sb at 1,200° C in CO-C02 atmospheres revealed the importance of the FeO:Si02 ratio and the basicity ratio, (CaO+MgO):SiO2, of the slag. Lead losses to slags increased with an increasing FeO:Si02 ratio and decreased with an in-creasing basicity ratio. Copper and indium distribution coefficients, [Lx =] increased from 15 at the lower basicity ratios to near 60 at higher basicity ratios. LTI values increased from 20 to 150 as slag basicity increased. Lcu, Lin, and LTI were relatively in-dependent of the FeO:Si02 ratio, but increased with greater amounts of accessory elements in the system. Antimony distribution alone was shown to be strongly affected by FeO:Si02 ratio, although data were scattered. LSb values ranged from 20 to 800 and decreased sharply with increasing FeO:Si02 ratios. The basicity ratio and the level of accessory element load did not have any noticeable effect on LSb.

Jan 1, 1983

By P. W. Jeran, C. M. McCulloch, Maurice Deul

The natural vertical fracture sys tem in bituminous coalbeds is called cleat. Cleat orientation commonly controls the direction of mining with major development paralleling the face cleat. Previous researchers have categorized the origin of cleat as endogenetic, relating the origin of cleat to compaction and coalification, and exogenetic, relating the origin of cleat to tectonic forces. In the coalbeds studied for this report it was found that tectonic forces were the controlling factor of cleat formation. Face cleats were formed as extension fractures during structural deformation, and butt cleats, as release fractures during erosion and uplift. The face cleat of the Pittsburgh coalbed rotates from N 80° W in north- western West Virginia to N 57° W in southwestern Pennsylvania ; the face cleat maintains a perpendicular orientation to the shifting axial trend of local structures . Cleat orientation in other bituminous coalbeds in Virginia, Utah, Oklahoma, and Central Pennsylvania showed a similar relationship to local structure. Directional permeability of coal is directly related to cleat. Holes drilled perpendicular to the face cleat yield from 2.5 to 10 times the amount of gas released as compared with holes drilled perpendicular to the butt cleat.

Jan 1, 1974