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By H. Kim, R. W. Plummer, T. J. Stobbe

"The probability of developing coal workers' pneumoconiosis (CWP) varies among miners in different geographic areas, coal seams, and jobs. Many studies have revealed the correlation between mineral content and the frequency and severity of CWP development still remains controversial. Furthermore, the mineral content and its variability in different areas is unknown.Since mineral content is expected to vary from location to location within a mine, between mines, between coal seams, and over time, this information will be valuable in understanding the variations in CWP incidence, as well as in establishing the appropriate kinds of dust to use in toxicological research programs studying CWP.Size-selective airborne dust samples were collected using 4-stage cassette impactors at 9 different locations in each of five coal seams. These coal seams were the Upper Freeport, Pittsburgh, Kittaning, Coal Burg, and Pocahontas. Mineralogical analyses were done by a x-ray powder diffraction photographic technique.Common minerals found in coal mine dust were illite, calcite, kaolinite, quartz, siderite, dolomite, gypsum, anhydrite, and pyrite. The distribution of minerals in interand intra location samples will be reported. Early results on the mineral content show wide variations between locations.in a mine and between coal seams, and small, but significant, variations between particle sizes.INTRODUCTIONIn spite of its long history of incidence, and the large amount of research conducted on it, coal workers' pneumoconiosis (CWP) is still prevalent among coal miners and needs further research to develop effective preventive and remedial measures. Although the dose-response relationship between simple CWP and coal mine dust has been established (1), the causal agent(s) and the mechanism(s) involved in the progression of simple to complicated CWP are not yet defined. Many plausible hypotheses have been made to explain the mechanisms involved in the disease progression however none of them is satisfactory. In addition, the source of variation in occurrence of CWP among miners in different geographic areas (2), rank of coal seam (3,4), and job (5) remain unsolved."

Jan 1, 1988

1. In 2001, a total of 785 nonmetal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Examples of nonmetal mining operations include the mining of clay, trona, barite, phosphate rock, gypsum, talc, gemstones, and pumice. Nonmetal mines comprised 5.4% of all mining operations.1 • Nonmetal mining operations are located in all but seven states or territories (Alaska, Delaware, Maine, New Hampshire, Rhode Island, Puerto Rico, and the Virgin Islands). • The median number of operator employees per nonmetal mine was 6.1.2 • Mines producing common clay comprised 31.2% (n = 245) of all nonmetal mining operations.

Jul 1, 2003

By P. Comba

The U.S. Bureau of Mines investigated a hydrochloric (HC1)-calcium fluoride (CaF2) leaching procedure to treat domestic manganese (Mn)-bearing silicate resources. The proposed process is an alternative to high-temperature and energy-intensive extractive techniques. Single-stage leaching with a stoichiometric amount of HCl and a F-Mn mole ratio of 0.2 extracted 96 pct of the Mn when the leach conditions were 50° C, 3 h, and 35 pct solids. Ninety-eight percent of the Mn was extracted during countercurrent leaching at similar conditions. A process flowsheet was developed that incorporated HC1-Cab leaching, excess leach acid utilization, fluoride (F) recycle, and Mn recovery. When the domestic manganese silicate ore was processed, 98 pct of the Mn was extracted, 99 pct of the Cab was reclaimed, and a leach residue was produced that passed the Environmental Protection Agency (EPA) Extraction Procedure (EP) Test for nonhazardous waste.

Jan 1, 2010

By A. M. Cummings

During August 1943, the Bureau of Mines undertook sampling and measuring of the Kennedy zinc tailing pile near Hazel Green, Lafayette County, south-western Wisconsin, as part of a general investigation of this lead-and zinc-producing area at a time when it was extremely important to increase the production of metals for the Nation's War program. The tailing pile was the residue from old jigging plants that treated ore from the Kennedy mine, one of the oldest and. largest mines in the district. Because retreatment of tailing by modern milling methods was proving economically successful at other sites in the southwestern Wisconsin field, the Bureau?s investigation was designed to assist the potential operators in evaluating the feasibility of a retreatment operation at this site. The study involved measurement of the tailing pile and sampling by means of auger to determine the average metal content within the narrowest possible limits. A total of 46 auger holes ranging in depths up to 40 feet and aggregating 886.5 feet of bore were drilled in the tailing pile, and weighted samples from each hole were analyzed and averaged to determine the zinc and iron content of the tailing.

Jan 1, 1949

By M. J. Brevoort

Research work in the Bureau of Mines cryogenic laboratory requires the use of high-sensitivity galvanometers of the d'Arsonval type in a building that is subject to unusually severe vibrations. A modified form of the galvanometer suspension described by Julius' has damped the vibrations so successfully that a short note concerning it is thought to be desirable. The laboratory is on the site of the Amarillo helium plant near a building that houses gas engines of from 180 to 250 hp driving compressors and electric generators. The distances from the galvanometers to the individual engines range from about 80 to 180 feet. The subsoil, consisting of black clay loam, transmits the impulses without much damping. The usual methods of protecting galvanometers from vibration were tried and proved fruitless. A Julius suspension purchased on the market was carefully installed in the hope that it would overcome the difficulty, but the conditions were too severe even for this elaborate arrangement. Several modifications of the original Julius suspension, which were then introduced, resulted in almost complete elimination of all vibrational effects. These modifications were suggested by careful study of the original idea embraced in the Julius construction. They were designed to give further constraint to motion in any direction other than that parallel to a line from the point of support through the center of gravity of the suspension, This was accomplished by making the suspended frame more rigid and by improving the means of adjusting each of the supporting wires to the same degree, thereby transmitting any impulse symmetrically through the three wires. The result was a suspension that is more effective, particularly for severe vibration, than the form described by Julius; also, it is believed to have advantages in stability, simplicity, and ease of adjustment over the few suspensions for this type of service that the author has found described in the literature.

Jan 1, 1931

By Paul T. Allsman

This paper gives the cost and describes the mining of 55 tons of nickel-bearing rock by hand methods from a prospect in southern Nevada, June 15, 1937, by the Mining Division of the Bureau of Mines. The geology, mineralogy, and problems related to future development also are discussed briefly. The main object was to obtain a 55-ton sample within the limited period during which funds were available; little time was available to make a first-hand detailed study of the possibility of commercial ore deposits being found. The sample was desired by the Metallurgical Division of the Bureau for experimental purposes at the Electro-Metallurgical Station at Boulder City, Nev. The term "ore" is used loosely in the following discussion to designate dike material containing nickel and copper, without consideration of its commercial value. ACKNOLEDGMENTS Material concerning the geology and mineralogy of the prospect and district as obtained from Geological Survey publications by Bancroft3/and Longwell4/.

Jan 1, 1938

By W. A. Cole

The sulfur shortage that existed during the Korean conflict stimulated interest in coal measures as possible sources of sulfur. One of the areas brought to the attention of the Bureau of Mines was in Marion County, Iowa, where comparatively high-sulfur coals and other marcasite-bearing strata were known to occur. A Bureau of Mines engineer inspected the marcasite occurrence on December 4, 1954; this prompted further work on the Iowa coals and associated formations as a source of iron sulfides. An investigation of the Iowa high-sulfur coals was undertaken including core drilling, field reconnaissance, and compilation of data pertinent to consideration of the following: 1. Upgrading Iowa coal by mechanical cleaning and the feasibility of recovering sulfur from coal brasses. 2. Possibility of processing the high-sulfur coals by adaptation of methods employed in processing industrial gases to produce sulfur and sulfur products. 3. Possibility of finding concentrations of iron sulfides in associated rock formations in sufficient quantity for economical recovery.

Jan 1, 1957

By Nancy S. Raymon

The Bureau of Mines investigated the effect of controlled additions of selected metal oxides, as well as the adjustment of the calcia-to-silica ratio on the high-temperature strength of refractory-grade periclase. Increases in the hot flexural strength of some periclase materials in the range of threefold to fourfold were obtained with additions of Zr02 and by adjustment of the CaO:Si02 ratio to the 2.5 to 3.0 level. Results show that for each periclase refractory raw material, there exists a combination of level of Zr02 addition and an adjustment to the CaO:Si02 ratio that optimizes the hot flexural strength of each of these materials. Data also indicate that the improved hot strengths can be attributed to the high-temperature secondary phases formed between the different levels of periclase impurities and the additives, resulting in improved intergranular high-temperature bond strength.

Jan 1, 1982

To assist coal mine operators and regulatory agencies in selecting the most appropriate method to treat coal mine drainage utilizing expert system computer technology. The software package is called the Coal Mine Drainage Treatment PRO. Approach Experts in the field of coal mine drainage treatment were interviewed to determine their methods of assessing mine drainage treatment problems and their rationale for selecting a treatment protocol. These diagnostic, selection, and design criteria were codified in an interactive set of computer programs. Expert systems permit the user to input specific site data and receive treatment advice customized to the user's site and treatment objectives. How It Works The Coal Mine Drainage Treatment PRO package developed by the U.S. Bureau of Mines (USBM) consists of four programs or modules: (1) a control module, (2) a mine drainage treatment tutorial module, (3) a treatment advice module, and (4) a reference module (figure 1). A context-sensitive HELP Facility is also provided.

Jan 1, 1996

By Martin Hertzberg

The Bureau of Mines 8-liter flammability system was used to study the effectiveness of a variety of powdered inhibitors in preventing the propagation of explosions of coal dust or methane in air. Over 35 different chemical additives were evaluated against Pittsburgh seam pulverized coal. The least effective inhibitors were the carbonates, which required mass additions in the range of two to three parts inhibitor to one part of coal dust in order to prevent propagation. The most effective inhibitors were the derivatives of ammonium phosphate, which were effective quenching agents at additions of only one part inhibitor to four parts of coal dust. Alkali halide powders were of intermediate effectiveness. These laboratory-scale results are in good agreement with full-scale mine experiments in all cases where detailed comparisons have been made. Data were also obtained for the effectiveness of several of the same powdered inhibitors against methane-air explosions. Their relative order of effectiveness and the concentration ranges required for quenching the gas explosion are comparable to those measured for coal dust explosions. Data are also presented for the effectiveness of N2 and CF3Br addition. Some preliminary data are also presented for powder addition to methane burner flames. Those data are compared with other burner data and evaluated in terms of their relevance to explosion tests.

Jan 1, 1982

By Joseph E. Matta, John C. LaScola, Fred N. Kissell

The Bureau of Mines investigated coal storage silos to determine how gassy coal must be for methane accumulations in a silo to become hazardous and where such accumulations are likely to occur. Methane concentrations were measured in the open space above the stored coal pile, in the pile, and in the reclaiming area. No methane layering was found in closed-top silos. Reclaiming areas were as gassy as the top part of the silos. Coal samples were collected from the conveyors entering the silos in order to assess the gassiness of the coal. No simple correlation was found between the gassiness of the coal stored and the measured methane concentrations. However, at mines where the average 24-hour gas emission from the conveyor belt samples was 14 ft3/ton or more, fans or open tops were used. It appears that a large fraction of the methane released during storage remains in the void space between the coal particles.

Jan 1, 1981

By David C. Oyler, Gregory Hasenfus, Gregory M. Molinda

Few studies have specifically measured and documented the large-scale loading behavior and durability of ventilation stoppings to mining induced movements, particularly from longwalls. Ventilation stoppings are more commonly the concern of ventilation engineers, and ventilation stopping response to ground movement has only been documented in an incidental manner. This paper presents the investigations of underground measurements that have been conducted to determine the loading response of stoppings constructed from lightweight aggregate concrete masonry units (CMU). These investigations have produced some interesting results that may prove beneficial, not only for developing and assessing alternative stopping construction techniques, but also for designing and selecting standard construction methods for use in varying mining conditions. For instance, the interface friction that results from wedging a CMU stopping during construction plays a substantial role in its ability to resist both lateral and vertical loads. Although they are not intended for ground support, the study showed that block stoppings can resist vertical loads of at least 2,700 to 3,000 kN. Asymmetric loading of a stopping may result in localized failure of blocks within a stopping, which, depending on the severity, can be a precursor of impending stopping failure. In addition to measurement results and implications, the paper will also present details of field measurement methods used to assess stopping response. Stopping stiffness and material strength characteristics will also be presented.

By Thomas V. Falkie, R. Venkataramani

Underground coal winning operations can broadly be classified as conventional, continuous, and longwall mining. In conventional mining, the operations of cutting, drilling, blasting, loading and hauling, and roof support are performed in that sequence in each working face in a work area. The major difference between continuous and conventional mining is that the coal is cut and loaded by a continuous miner in the former, thereby combining the unit operations of cutting, drilling, shooting, and loading into one. Longwall applications have been viewed with great interest in recent years, and although at the end of 1970 there were only 37 longwall installations in the U. S. with combined production of less than 4 percent of underground total, there is no question about the growth potential of longwall in the United States. Increased capacity, versatility, and power characterize continuous miners today. Although continuous miners have outsold conventional gathering-arm type loading machines for some years, the latter, in the new extra-high capacity types, are continuing to find wide use. Whether the mining system is continuous or conventional, the haulage units may include six-wheel articulated shuttle cars, tractor-trailer units, or extensible belt and bridge-conveyor systems, all tending to increase the productivity of the face units. The decision as to which to choose - continuous or conventional mining - is complicated, and both systems are capable of high production rates. Most continuous miners in use today have a revolving pick-mounted drum to cut the coal and a gathering arm loading unit. Functionally, there is little difference between the loading unit in a

Sep 1, 1972

By George S. Rice, L. C. IlsLey

"A remarkable explosion of fire-damp caused by a discharge of lightning at the new shaft at the Sitalpur coal mine, has been reported by the Chief Inspector of Mines of India, who gave the following details:""The explosion occurred during a thunderstorm, and the evidence showed that a flash of lightning had, to all appearances, passed down the shaft caus¬ing disruptive discharges at certain points between the guides and the winding rope, rending the latter at two places situated respectively .228 .feet and 278 feet from the surface, The distance between the winding rope and the side of the shaft was 5 feet 4 inches, indicating a spark gap ;of this width, and an intensity of discharge which could not fail to ignite the explosive mixture of gas and air known to be present in the shaft.""The Compressed Air Magazine, January 1920 issue, which contained the above extract also goes on to state;""In 1915, M, Ferey described in a paper read before the Societe de l'Industrie Minerale phenomena of a similar character to the above. In a pit liable to sudden outbursts of gas, for the sake of safety, shot firing was carried out from the surface. During a storm, in the year 1905, shots went off in two places after the detonators had been connected to the conductors) we read in the Colliery Guardian, London. These shots were situated respectively 1,400 and 1,410 metres from the firing station, Realizing the possible danger from this cause, the precaution was taken to cut the conductors at the bottom of the shaft and to connect there just before firing, Even under these conditions a shot went off spontaneously, -.owing, it is believed, to lightning."""

Feb 1, 1920

The results of a Feasibility and Design Study of Surface Impregnation Equipment to be used for Chemical Stabilization of Coal Mine Structures are described in this report. The study was sponsored by the United States Department of the Interior, Bureau of Mines, under Contract H0210055. This program was undertaken as an essential part of the Bureau of Mines Chemical Ground Stabilization Program. The responsible prime contractor was The Eimco Tunneling and Mining Machinery Division of the Envirotech Corporation. The Rocketdyne Division of the North American Rockwell Corporation performed part of the feasibility study and design and testing of the metering and feed system as a subcontractor to Eimco.

Jan 1, 1972

By Steven E. Mischler

The exposure of mine workers to diesel particulate matter (DPM) and gases is an issue of great concern to the underground mining community in the United States. Approximately 30,000 underground miners are potentially exposed to high concentrations of DPM. In January of 2001, the U.S. Mine Safety and Health Administration (MSHA) promulgated rules setting compliance standards for both underground coal and metal / nonmetal mine workers. As industry works to achieve compliance with these standards, mine operators are looking for feasible methods for reducing DPM concentrations in their mines. In addition, the industry needs methods to accurately measure DPM to ensure that the control strategies they adopt are working successfully. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) conducts research to evaluate control technologies and monitoring instrumentation that can be used to reduce the diesel particulate matter (DPM) exposure of mine workers. An overview of the strategies being utilized in underground US mines to reduce DPM concentrations will be presented. Also, updates on the development of diesel monitoring instruments such as the continuous elemental carbon monitor or the Personal Dust Monitor for DPM measurement will be provided.

Jan 1, 2010

By Russell J. Foster

This Bureau of Mines review focuses on the extent to which technologically and economically feasible programs in substitution, improved processing practices, including recycling, and design can achieve conservation of cobalt, chromium, manganese, and platinum-group metals, and thus reduce U.S. vulnerability to interruptions of supply. In addition, supply-side options--domestic and foreign resources, ocean minerals, and stockpiles--are identified. The report consolidates four major studies on these strategic and critical minerals sponsored entirely or partially by the Bureau in the last few years. These studies have been updated with further information from the recent literature.

Jan 1, 1985

By R. L. Grant

At the Eighth International Conference of the Directors of Safety in Mines Research, Sartorius and Thouzea5/ presented and discussed data obtained in explosives tests made under varying conditions of humidity. These tests showed that there was less probability of explosives failure when the humidity of the testing gallery atmosphere was high. As it is to be expected that the relative humidity of mine atmospheres where permissible explosives are used will not be identical with that of the test-gallery atmospheres, the influence of atmospheric moisture upon the incendivity of permissible explosives is of the utmost importance if decreasing humidity reduces the relative safety of an explosive. Because of this and because the question has recurred frequently in discussions of gallery testing at Bruceton, Pa., it was decided to investigate the effect of humidity and ambient temperature on the ignition of firedamp by explosives, applying the small-scale gallery methods developed at the Bureau of Mines and used earlier to study the fundamental causes of such ignitions.6 7 8/

Jan 1, 1956

In the three years to June 2005, 959 injuries associated with continuous miners (CMs), shuttle cars (SCs), load-haul-dump and personnel transport (PT) were reported by NSW underground coal mines, comprising 23% of all injuries reported. The present paper reports an analysis of the narrative field accompanying these reports to determine opportunities for controlling injury risks. The most common combinations of activity and mechanism were: strain while handling CM cable (96 injuries); caught between or struck by moving parts while bolting on a CM (86 injuries); strains while bolting on CM (54 injuries); and slipping off a CM during access, egress or other activity (60 injuries). For the other equipment considered, the common injury mechanism was the vehicle running over a pothole or other roadway abnormality causing the driver or passengers to be injured (169 injuries). Potential control measures include: monorails for CM services; hydraulic cable reefers; handrails on CM platforms; redesign of CM platforms and bolting rigs to reduce reach distances during drilling and bolting; improvements to guarding of bolting controls; standardisation and shape coding of bolting controls; two handed fast feed; improvements in underground roadway maintenance, vehicle suspension, visibility and seating; and pedestrian proximity warning devices.

By L. C. IlsLey, E. J. Gleim

It is the firm belief of the Bureau's engineers that the introduction of electrical mining machines has done much to increase safety in mining as a whole . There can be no doubt but that the substitution of machine mining together with permissible powder for the method of " shooting from the solid " has been the means of saving the lives of many shot- firers . Machine mining also leaves the roof in a better condition as lighter charges of powder are required to bring down the coal . Thus the danger from falls of roof are lessened . It is recognized that every effort should be made to prevent all accidents due to the use of electrical machinery but it is felt that any action tending to limit the use of such machinery would be a backward rather than a forward step in the safety measures laid out to decrease the hazards in coal mining .

May 1, 1920