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By J. D. Davis

THE carbonizing properties of one medium- and and five low-volatile coals from West Virginia and one high-volatile A and two medium-volatile coals from Pennsylvania were determined by 800° and 900° C. BM-AGA carbonization tests and expansion tests in the sole-heated oven. Plastic properties of the coals and the yields and quality of their cokes and other carbonization products were determined. The low-volatile coals comprised a mine and a coke-plant sample of Pocahontas No. 6-bed coal from the. Black Eagle No. 1 mine, Wyoming County, W. Va.; a mine sample of Pocahontas No. 6 bed from the Louisville mine, Mercer County, W. Va. ; Davy Sewell bed was sampled at the Twin Branch mine, McDowell County, W. Va.; and Fire Creek bed was sampled at the Dunedin No. 1 mine, Raleigh County, W. Va. The medium-volatile coals were from the Fire Creek bed, Laurel Creek mine, Greenbrier County, W. Va.; Lower Kittanning bed, Springfield No. 4 mine, Cambria County, Pa.; and Upper Kittanning bed, Springfield No. 6 mine, Clearfield County, Pa. The high-volatile A coal represented the Upper and Lower Freeport beds, Kent Nos. 1 and 2 mines, Indiana County, Pa. In addition to the coals listed, high-volatile A coal from the Pittsburgh bed, Warden mine, Allegheny County, Pa., a standard blending coal, was used in blends in this investigation.

Jan 1, 1950

By John C. Machisak

Injury data and experience, with related employment statistics, at coal mines in the United States for 1960 are presented in this publication under the following general sections: A General injury experience: Tables 1 to 6: Current data on number of injuries, decree of injury, frequency and severity rates, average severity, and related employment and production data by work location. B Selected injury experience: Tables 7 to 38: Current data on principal agencies of injuries, distribution of injuries by part of body injured, days of disability, extent of hand and machine loading, experience by employment and production groups, and various other operating factors and physical conditions related to the occurrence of injuries at the Nation?s coal mines.

Jan 1, 1962

By Corale L. Brierley

Accumulations of microorganisms in the in-situ leaching environment are believed responsible for plugging of the orebody and thus decreasing uranium extraction. To assess the contribution of microbial growth to this problem, packed columns of ore and core specimens were leached in the laboratory. Samples collected at four in-situ uranium mining operations revealed pseudomonads, xanthomonads, Bacillus sp. and Micrococcus sp. in numbers of 105 cfu/ml. These microorganisms, inoculated into simulated leaching conditions, decreased permeability in two uranium ores by one order of magnitude in 20 days. Hydrogen peroxide (0.2 g/l) alleviated microbial plugging in the laboratory. Periodic injection of hydrogen peroxide through the production well into the orebody may reduce microbial plugging problems in the field.

Jan 1, 1982

By Carl R. Peterson

[In lTI n,v und I'gr'oun nllnin~ Opt'I'ali n' the high . t cost is the loading and I 3ulage of t tln-of -D"'line ot'. 01' hauling costs can be r duced signifi-cant\v with the us ~ (r \) >It corn'e)'OI' " a COnlTllOn pl'acti c i.n coal and other s 0 t'L rn I n r' a l III i, n e , '. Jf 0 vel s i z ' () f' e can bee 1 i 11.11 tl ate I rH'i 0 I' lO C n v e . in g, ]

Jan 1, 1976

By H. L. Gibbs

Many factors contributed to the decision to build a radiochemical laboratory at the Salt Lake City Metallurgy Research Center to investigate the application of radioactive isotopes and chemical compounds in extractive metallurgy. These reasons included the notable success achieved in biological sciences with radioisotopes, the development of reliable instruments and methods for identifying the isotopes and measuring their activities, and the commercial availability of radioisotopes in a variety of forms and known activities. The paramount reason, however, was the realization that better methods were needed for guiding and quantifying research to resolve the complex extractive metallurgy problems under study at the Research Center. This is the first of a series of reports describing the application of radioisotopes and radioactivity techniques in extractive metallurgy. The report includes a discussion of licensing and safety requirements, a general description of the laboratory and the methods used, a definition of the nature and scope of the research program, and a synopsis of the more important problems studied. Subsequent reports will concern radioactive techniques for solving specific problems in mineral dressing, hydrometallurgy, and pyrometallurgy.

Jan 1, 1960

By R. S. Dean

This report, the third of a series of annual reports of the Metallurgical Division to be released in this form, covers the fiscal year July 1, 1936, to June 30, 1937. The technological work of the division is performed by sections. Thus, an efficient organization is provided to prosecute the various problems under investigation, and a logical system is set up for presenting the material contained in this report.

Jan 1, 1937

By JOE SIERAKOSKI, W. R. Hardwick

This paper , which describes mining methods and practices at the Johnson Camp copper -zinc mine , Coronado Copper & Zinc Co. , Cochise County , Ariz . , is one of a series being prepared by the Bureau of Mines on mining methods , practices , and costs in various mining districts of the United States . Johnson Camp is in the eastern foothills of the Little Dragoon Mountains in secs . 23 , 24 , 25 , and 26 , T. 15 S. , R. 22 E. ( fig . 1 ) . The mining property is in the low, rolling foothills at an altitude of slightly over 5,000 feet above sea level ( fig . 2 ) . The area is covered with scattered grass and small desert shrubs . The climate is mild , with hot summers and mild winters . The average annual precipitation is about 12 inches . The nearest surface water is the San Pedro River , some 12 miles west of the mine . The property is owned by the Coronado Copper & Zinc Co. , Los Angeles , Calif . This report gives a brief history of the property , describes the general geology of the area and of the ore deposits , outlines the methods of prospecting and exploration , and gives the methods of sampling and of estimating ore reserves . Development and stoping methods are explained . Underground transportation , ventilation , mine drainage , and safety measures also are described . The last section gives a brief description of the milling practice .

Jun 1, 1957

By W. H. Tomlinson

Although the thoughts and efforts of the great majority of people in many parts of the world are today directed toward killing each other, the purpose of this paper is to discuss means of conserving human life. In a world of turmoil and strife, we find time to discuss and make plans to achieve our objective -prevention of the "sacrifice" of life through avoidable accidents. The word" sacrifice" is used here advisedly, as one meaning of the word given in the 1942 edition of Funk and Wagnalls New Dictionary of the English Language is "the act of giving up some desired or valued object for the sake of *** future good." As everyone agrees that life is man's most priceless possession, one wonders if past sacrifices have been in vain. It appears that life is cheap in America; it is cheap because some of the industrialists are too much concerned with making a profit to devote much time and thought to conserving human life; it is cheap because some labor leaders apparently are interested solely in personal power and prestige; it is cheap because a great many workmen fail or refuse to cooperate energetically with the various organizations interested ill; their safety and welfare; it is of little value because, individually and collectively, we are indifferent to our responsibilities toward our fellow men.

Jan 1, 1944

Consumption and intensity of use trends for twelve metals, by industrial end use, were estimated for 1972 through 198Z. The trends were then forecast through 1993 using standard statistical methods. The intensity of use measure selected is the quantity of metal consumed per constant dollar output of a specific industrial sector. The metals studied were aluminum, chromium, cobalt, copper, lead, manganese, nickel, the platinum-group metals, tin, titanium, tungsten, and zinc. Average annual growth rates for the following four of the twelve metal increased from 1972-82 as follows: aluminum, 1.00 percent; platinum-group metals (consisting of platinum, palladium, and iridium), 8.83 percent; titanium, 7.82 percent; and tungsten, 6.09 percent. Consumption. for the remaining eight metals decreased at average annual rates ranging from 0.58 percent (copper) to 5.37 percent (manganese).

Jan 1, 1986

By Bernard Lewis

The ignition problem: for a layer of firedamp bordering on a cloud of detonation products is evidently considerably more complicated than in the usual laboratory ignition experiments, in which a well-defined volume of gas is heated and the occurrence of ignition is observed after an induction period. An atmosphere of firedamp exposed to the detonation of a high explosive is subjected to heating by shock-wave compression and thermal conduction and to intermixing at the interface of the firedamp atmosphere and the cloud of deto¬nation products. Although a reliable physical-chemical analysis of the problem is not yet possible, one may nevertheless form a general view of the role of compression waves and the processes of heat transfer and diffusion at the interface. Near the mouth of a shot hole, or near a freely suspended cartridge, the firedamp atmosphere attains very high temperatures by adiabatic compression, and it is certain that such temperatures are sufficient to initiate chemical reaction. The pressure wave pattern is reproducible from one test charge to another if the initial experimental conditions are held constant; on the other hand, experiments on firedamp ignition do not yield a reproducible threshold condition for ignition, but only an ignition probability. Thus, the induction periods are sufficiently long that there is time for the compressed', heated gas layers to undergo random changes that may quench or promote ignition. Therefore, the analysis of the ignition problem hinges primarily on the discovery of the random events that modify the chemical reaction in the activated gas layers.

Jan 1, 1948

By Wendell R. Peters

Shallow underground voids resulting from early coal mining and other resource recovery activities over the past several decades are now being recognized as a significant cause of ground subsidence problems in developing urban areas. Uncertain knowledge of abandoned coal mines also imposes potential hazards in coal excavation operations since water inundation or the release of methane gas is a pricnipal hazard when mine excavation operations break into an abandoned mine. U.S. Army requirements for an effective method for detecting and mapping subversive man-made tunnels have resulted in a surface-operated automatic earth resistivity survey system with a digital computer data processing system. Field tests aimed at demonstrating the system performance resulted in successful detection of tunnels having depth-to-diameter ratios up to 15 to 1. Under the sponsorship of the Bureau of Mines, a similar system was designed and constructed for use in the detection of coal mine workings. This report discusses the hardware and software aspects of the system and the application of the high-resolution earth resistivity method to the survey and mapping of abandoned coal mine workings. In the field tests reported, the targets of interest were both air-filled and water-filled workings.

Jan 1, 1980

By Martin Hertzberg

The concept of limit burning velocities, formulated in an earlier Bureau of Mines report (RI 8127), is applied to the problem of flame propagation through tubes of finite size. The limit burning velocity for conductive-convective wall-loss quenching (process b) is (Su)b = [aPe,] where the proper choice of critical Peclet constant, Pe, is determined mainly by the ratio of contact-perimeter loss area to flame-zone cross sectional area. This ratio of loss area to propagation area relates to the shape of the flame front and its control by buoyancy and by boundary conditions. The comparison of (Su)b with previously defined limit velocities for systems mixed by natural convection allows one to assess the influence of tube dimensions and boundary constraints on the "true" or earthly limits for the three directions of propagation. The flame quenching caused by inert powders is shown to be similarly described in terms of a limit burning velocity, (Su)?b. The tube's surface-to-volume ratio (~1/ro) is simply replaced by the powder's surface area per unit volume of the flammable mixture. Thermal loss quenching by these "internal walls" occurs at a critical Peclet constant somewhat higher than that observed for tubes, and the problem is complicated by the finite heat capacities of the powders and particle lag effects in the flame front.

Jan 1, 1980

By S. L. Weber, D. E. Banks

"Silicosis was first reported by the ancient Greeks and is apparently as old as human history. The prevalence of this illness peaked in the last half of the 19th century and the early part of this century, when mechanized industry was developing and the relationship between dust exposure and disease was less well understood. Yet, even today in devel-oped countries, sporadic outbreaks of silicosis occur when workers are consistently exposed to silica particles of respir-able size (0.5 to 5.0 µm in diameter) at levels exceeding those recognized to be safe.Silicon dioxide or silica. is the earth's most abundant mineral. Silica is considered to be either free (i.e.. unbound to other minerals) or combined. Minerals with high amounts of free silica include quartz (including granite) flint. Chert, opal, chalcedony, and diatomite. Combined forms of silica are called silicates and include, among others, asbestos talc and kaolin.In the crystalline form, silica exists as quartz, cristobalite, and tridymite (Fig. 28). Of these quartz is ubiquitous in the environment and occurs as sand and as a part of many rocks. Cristobalite and tridymite occur naturally in lava and can be formed by the heating of quartz or amorphous silica. Cristo-balite is more tibrogenic than quartz. Amorphous silica is noncrystalline and, therefore, is relatively nontoxic and does not cause silicosis. It occurs as diatomite (skeletons of pre-historic marine organisms) or as vitreous silica (glass), the result of carefully melting and then quickly cooling free crystalline silica. Heating diatomite with or without alkali (a process known as calcining), forms cristobalite and adds the respiratory toxicity of free crystalline silica.There are many opportunities for occupational exposure to respirable crystalline free silica. Some of the commonly en-countered occupations in which the risk of silicosis exists are reported in Table 20.Silicosis. the pulmonary disease caused by the inhalation of silica particles of respirable size, is most commonly cate-gorized by findings on the chest radiograph. The most typical presentations simple silicosis and progressive massive fibrosis appear different radiologically but are grouped under the category of classic silicosis because they are a part of the radiographic spectrum of this illness. Radiographically, simple silicosis appears as small (less than 10 mm in diameter), rounded opacities, typically predominant in the upper lung zones. Progressive massive fibrosis is the result of the coalescence of these small nodular opacities and appears as larger opacities (more than 10 mm in diameter), again typicallydistributed in the upper lung zones."

Dec 1, 1995

By Launa Mallett, Charles Vaught, Michael J. Bmick

Since 1991 the Pittsburgh Research Center (PRC formerly part of the U. S. Bureau of Mines) has been tapping u valuable resource-researchers have recorded extensive interviews will, 30 individuals who are recognized as experts in the area of mine emergency response. These veterans related stories and observations from events experienced during as many as 47 years of response activities. Overall, the response veterans averaged 29 years of mine emergency response experience and 35 years mining experience. Individuals [ ] interviewed included representatives from mining companies, the UMWA and state and federal government agencies. This information was gathered so dial it could he provided to today's miners and to tomorrow's emergency response personnel. It is hoped the collective wisdom that has been obtained can be used to help train new responders and guide those decisions which mill have to be made on the scenes of future events. During interviews file emergency response experts were asked to discuss lessons they had learned through experience. The interviewers asked them to tell what they had learned that would cause them to handle similar situations differently and to tell about things they saw at past events shat the would warn others not to do in the future. In response the experts discussed a variety of things. Most of their responses, however, touched on some of the same topics including: preparedness, experience people on-site mine rescue teams, and decision making. A summary of their responses provides alt overview of [lie lessons learned on-site at tile largest mine disasters in the country.

By J. W. Howland

To determine their effectiveness in different climate and soil conditions, a demonstration of dozer blades specifically designed for recontouring mine spoil was conducted at an East Texas surface coal mine. The specialized equipment included a 48-foot angle blade, a modified 24-foot "U" blade, a 13-foot deep "U" blade, and a 24-foot grading bar. Both the 4b-foot and the 24-foot "U" blades were mounted in a two-tractor, single-operator configuration. To meet flotation problems common in this mining region, a 22-foot lightweight blade was developed and demonstrated for use on a 400-430 hp tractor. The demonstration involved 1,185 acres and showed a 50% reduction in reclamation costs and a 47% reduction in fuel requirements for this mine site over conventional equipment. Improved equipment, trained operators, good supervision, and improved monitoring techniques contributed to the savings. Procedures and results of the demonstration are presented and analyzed here along with guidelines for application of findings.

Jan 1, 1981

By T. D. Hackett

Multislice mining methods were analyzed by the U.S. Bureau of Mines to determine their application to western United States thick coal seams; ground control, geology, and costs were considered. Multislice mining is used in widely varying seam conditions worldwide, including flat seams too thick to mine in a single pass, pitching thick seams, and seams containing a rock parting. Longwall multislice methods predominate, but room-and-pillar variants also exist. The initial use of the method in western seams is planned at a deep Colorado mine where a rock parting will be used to separate two slices mined by longwall. Ground control and spontaneous combustion are major hazards associated with multislice mining. A well-consolidated upper slice gob can reduce ground control problems and provide a seal against spontaneous combustion. Geologic analysis indicates that the consolidation of the gob depends on the composition of the upper slice roof, the presence of water, and sufficient overburden pressure. A geologically competent intermediate rock parting can also reduce ground control problems and seal against spontaneous combustion. To compete in western coal markets, the cost of multislice mining must be within the range of normal longwall costs. Analysis indicates that multislice operating costs should be within this range, and that multislice mining costs decrease as panel width increases. Relatively wide (600 to 800 ft) panels also provide increased coal recovery.

Jan 1, 1990

By D. G. Leddy, J. B. Johnson, L. D. Gratz, S. T. Bagley

"Studies have been conducted at Michigan Technological University (MTU) for over twenty years on methods for characterizing and controlling particulate emissions from heavy-duty diesel engines and die resulting effects on regulated and unregulated emissions. During that time, control technologies have developed in response to more stringent EPA standards for diesel emissions. This paper is a review of: 1) modem emission control technologies, 2) emissions sampling and chemical, physical and biological characterization methods and 3) summary results from recent studies conducted al MTU on heavy-duty diesel engines with a trap and an oxidation catalytic converter (OCC) operated on three different fuels. Control technology developments discussed are particulate traps, catalysts, advances in engine design, the application of exhaust gas recirculation (EGR) and modifications of fuel formulations. Methods for dilution tunnel sampling, particle size analysis, chemical analysis with emphasis on polynuclear aromatic hydrocarbons (PAH) and nitro-PAH, and biological characterization using mutagenic activity (Ames) assays are described, along with statistical approaches to experimental design and data analysis.In studies at MTU, both particulate traps and an OCC have been shown to be effective for the reduction of total particulate mauer (TPM), with the OCC being better al reducing all forms of hydrocarbon emissions, including PAH and nitro-PAH, and with the traps being better at removing the solids (SOL). The use of low sulfur fuel (0.Ql % by mass) has led to additional reductions in TPM; the low sulfur fuel has been shown to reduce the number of small, nuclei-mode particles for one of the engines tested. PAH, nitro-PAH, and mutagenic actively levels generally decreased with use of either the traps or the OCC.INTRODUCTIONDuring the 1980s and the early 1990s there have been significant advancements in the development of technology to control diesel particulate emissions. Efforts have been focused on internal control of the engine by design, the use of after-treatment devices, and improvements in fuel formulations to reduce all the diesel emissions. The research and development activities have been driven by the need to meet the US EPA heavy-duty vehicle standards shown in Table 1. The important standards for new technology are the 1994 heavy-duty vehicle 0.1 gm/bhp-hr particulate, the new urban bus 0.05 gm/bhp-hr particulate standard for 1996 and the heavy-duty vehicle 4.0 gm/bhp-hr NOx standard for 1998."

Dec 1, 1995

By Alexander May

The U.S. Bureau of Mines investigated the application of oxidation-reduction potential (ORP) and pH measurements to environmental studies of mining and mineral processing wastes, and developed a computer program to estimate the concentrations of species of lead present in samples from a lead processing waste site. The methods and techniques for the ORP-pH measurements were investigated using known standard solutions made in the laboratory, samples from a ferric oxide waste disposal pond at a rutile production plant, and samples of well water and stream water from the lead processing waste site. ORP values were measured from 5 to 80 °C, from pH 1 to pH 12, and at various ratios of oxidant to reductant. The ORP-pH values can help identify valence values and species of ions present, including those of major, minor, and trace concentrations, and also indicate possible reactions at various pH values. The ORP measurements versus temperature yield data from which thermodynamic values can be calculated. The application and limitations of these measurements are discussed, and a brief discussion of the computational program to identify species of lead is presented.

Jan 1, 2010

By J. F. Barkley

During the present war emergency, under the urge of the Federal Government to store coal, the following; questions are arising n the minds of coal users: (a) Will the coal lose any of its heating value in storage? (b) Will it slack and give a smaller-size coal? (c) Will its burning characteristics change in any way? (d) Will it catch fire from spontaneous combustion? (e) What precautions should be taken when storing coal? In regard to the loss of heating value of coal in storage, tests made by the Bureau of Mines show that the loss commonly has been overestimated. Various types of storage tests were made on New River, Pocahontas, Pittsburgh Gas, and Sheridan Wyoming coals. The following is quoted from Bureau of Mines Bulletin 136, Deterioration in the Heating; Value of Coal During Storage, by H. C. Porter and F. K. Ovitz:

Jan 1, 1942

By J. H. Adkins

The purpose of this research is to identify hazards associated with roof bolting and to make recommendations for procedural and equipment design changes to reduce those hazards. To that end, the project reviewed Literature on related research, collected and analyzed roof bolting injury data, normalized the injury data be exposure time to each activity and identified problem areas within the root bolting tasks. In addition, field data collection forms were prepared and mines selected for field work. In the field, observations were made of eighty (80) different roof bolting crews bolting one hundred fifty-five (155) place;, on forty (40) sections spread among nine (9) mines. Task analysis forms were used to record unsafe behavior or conditions for each crew and each place. Informal discussions were held with the mine's safety and training officer, the maintenance officer, one section foremen and, when possible, the observed crew, concerning the training and experience of the miners. Unsafe acts were categorized and related to the "Activity While Injured" categories developed during the accident analysis. For each of these categories one or more recommendations for corrective measure, machine modification, procedural change or job training were developed. The study produced over fifty (50) specific recommendations involving machine design, procedural, safety training and supervisional issues that would lead to reduced roof bolter injuries in the near term. The authors concluded, however, that only the development of truly hands off/remote bolting can eliminate or reduce to an absolute minimum the hazards to which the roof bolter is subjected.

Jan 1, 1977