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By W. E. Miller, G. S. Scott, G. W. Jones

"An important activity of the Bureau of Mines is the promotion of safety in mining and industry. In connection with these activities, the Bureau determines the explosion hazards of combustible gases, liquids, and solids and investigates means by which explosions may be eliminated or reduced in violence.The limits of inflammability and ignition temperature of combustible gases, vapors, and solids are of practical importance because such materials can be manufactured, transported, and used with greater safety, provided the range of concentrations and temperatures that cause explosions are known.Many organic compounds, which until a few year ago were merely laboratory curiosities, are now being manufactured in large quantities owing to the national emergency, particularly those chemicals entering into the manufacture of synthetic rubber, a product that is playing a major role in the Government program of national defense. This re Jolt gives results relative to the limits of inflammability of styrene and its ignition temperature in air and oxygen. This combustible liquid is now used extensively in the manufacture of synthetic rubber."

Mar 1, 1942

By Claude A. Tongish

This Federal Bureau of Mines report presents information on the accumulation and distribution of helium in U.S. natural gas reservoirs. The investigation concerns the relationship or association of helium with geographic location, geologic age, reservoir depth, nitrogen, carbon dioxide, and argon. Although helium is a minor constituent in natural gas, these data show that certain conditions make some reservoirs statistically more favorable than others for the accumulation of helium. The report is based on gas analysis information collected-by the Bureau from 1917 to 1974 from 10,086 gas samples, representing 6,455 reservoirs in 35 States. The occurrence of helium in the reservoirs was 11.5 percent with less than 0.005 percent of helium, 70.9 percent with 0.005 through 0.29 per-cent of helium, and 17.6 percent with 0.30 percent or more of helium in the gas. Results of the various correlations are presented in tables and charts. Relationships have also been determined quantitatively by measures of correlation. The statistical data can be used to determine the environment under which reservoirs with high-helium contents are most likely to occur. These data can be used with other information for predicting the future helium resources of the United States.

Jan 1, 1980

By H. P. Greenwald

For some years past the Safety in Mines Research Board of Great Britain has been making an intensive search for. materials that would be more efficient than rock dust and that could replace it wholly or in part as a moans of preventing the prorogation of coal-dust explosions in mines5/ In the course of this work several rock ducts and numerous inorganic compounds were tested. The results place incombustible substances in two main groups; (1) Those whose effect in suppressing the combustion of coal dust is proportional to their capacity for absorbing heat, and (2) those that shoo much higher effectiveness than would be expected from their heat capacity. The first group includes several inorganic compounds and materials commonly ground for use as rock dust, such as shale, gypsum, and limestone. Outstanding examples of the second group are compounds of the halogens6/ with the alkali metals,7/ especially potasium and sodium8/. British investigators term those salts "inhibitors" because it is assumed that their presence has a hindering or inhibiting effect on one or more of the chemical reactions that together constitute combustion. In other words, the action of an inhibitor is postulated as chemical rather than physical; theoretically, the effect is to prevent liberation of energy instead of to absorb energy already liberated.

Jan 1, 1940

By Forrest T. Moyer

The safety record of the mineral and mineral-fuel mining and processing industries in 1966 was improved slightly for the second consecutive year as indicated by reduced injury-frequency and injury-severity rates. The overall operating activity was higher in 1966, as measured by the increased number of men working and the total man-hours of worktime. Injury Experience.-The rate of occurrence of all disabling work injuries in the mineral industries was 17.38 per million man-hours in 1966. This overall rate comprised frequencies of 0.28 for fatal and 17.10 for nonfatal work injuries, compared with respective rates of 0.28 and 17.26 in 1965. Fatalities totaled 543; 5 more than in 1965. The total of 33.091 nonfatal injuries was 291 higher than in 1965. However, the larger number of disabilities was offset by the increased worktime in 1966. so that the fatality frequency was unchanged and the nonfatal frequency rate decreased from 1965.

Jan 1, 1967

By Ernest F. Burchard, J. R. Thoenen

"INTRODUCTION Technically speaking, bauxite is not a definite mineral but a mixture of several minerals belonging to a group of partly consolidated material known as laterite, which have been formed by surface weathering of rocks.The term bauxite is applied to the ore of aluminum, although a substantial amount is used for other purposes, such as a base in certain chemical industries and in the manufacture of artificial abrasives, refractories, and certain cements. Although bauxite has not been classed as strategic it now appears that the domestic supply may be insufficient for expanded defense requirements.Until recently, domestic production of metallic aluminum has been ample to meet requirements, but estimates of pyramiding future needs of the defense program have caused serious attention to be directed to the self-sufficiency of this country, both as to the supply of the raw material, bauxite, and the metallurgical capacity available to convert the ore to metallic aluminum.At the request of the Secretary of the interior, representatives of the Bureau of Mines and the Geological Survey recently investigated domestic resources of bauxite.A preliminary study of published literature and a field investigation disclosed that"

Nov 1, 1941

By W. G. Pariseau

A U.S. Bureau of Mines case study of pillar recovery in high-grade ore near the Ross shaft at, the Homestake Mine, Lead, SD, has demonstrated the usefulness of the finite-clement method for the evaluation of shaft pillar mining plans and shaft stability. This report, one of three in a series describing the Ross shaft pillar case study, focuses on the premining stability analysis. The two-dimensional computer program UTAH2 was used in advance of pillar mining; results suggested that the shaft would remain stable. Subsequent reports describe parts 2 and 3 of the study. In part 2, borehole extensometers and other instruments were installed to provide data for model verification and shaft monitoring. Results of the recalibrated two-dimensional model confirmed the premining stability evaluation. However, after mining began, great concern developed because of the appearance of cracks and other signs of ground movement over considerable distances from the area of active pillar miping. In part 3, an intense three-dimensional modeling effort using UTAH3 was initiated. The results again showed that the shaft would remain safe. Three-dimensional analyses of alternative pillar mining scenarios indicated that more of the shaft pillar ore reserve could be recovered than previously thought.

Jan 1, 2010

By M. Hertzberg

This Bureau of Mines report describes experimental and theoretical studies of diffusion flames in free convection. The cross-coupling between buoyancy-induced flows and the combustion process is explored as it relates to the size, structure, and radiative balance of flames. New data are presented for the size-dependent radiance oscillations of diffusion flames and for the angular distribution of the total radiant intensity from a small methanol pool flame. Both amplitude and frequency of the measured oscillations are compared with theoretical predictions that are based on a new view of the structure of diffusion flames. This new view, which is at variance with the traditional one, assumes uniform reaction in the diffusive mixing zone, and recognizes the significance of the role played by convective buoyancy and its duality in both aiding and impeding flame propagation. Buoyancy quenches propagation at low burning velocities, introducing a real discontinuity in the combustion rate. A "flammable volume" is thus defined as that bound between lean- and rich-limit contours. However, in the flow disturbances generated by combustion waves that consume that volume, buoyancy aids propagation by promoting the convective mixing of a new flammable volume. The measured radiance oscillations are manifestations of these propagation and remixing cycles.

Jan 1, 1978

By Elaine T. Cullen

Underground mining, like many high-risk industries, is facing a crisis in the near future. This industry has traditionally relied on a master-apprentice relationship to train new workers, but experienced miners are retiring in large numbers, leaving few "masters" to properly train their replacements. With a recent resurgence in mining, many new miners are entering the workforce each day. The rise in the number of inexperienced workers has implications for worker safety in an industry in which one mistake can blow up the entire workplace. The explosion in the Darby Mine in May 2006 that killed five miners illustrates what can happen in hazardous environments such as underground mines. The Health Communications Team at the National Institute for Occupational Safety and Health Spokane Research Laboratory was asked to address this problem by developing new training and safety awareness materials to promote safe flame cutting and welding practices. This article describes how occupational ethnographic techniques provided insights needed for "new product development." The result of this work was a national initiative to raise awareness and to protect underground coal miners from the dangers of flame cutting and welding in an environment filled with solid fuel and methane (natural gas). Although this project was initially designed for the mining industry, the approach and lessons learned are applicable to any high-risk industry and should be of interest to other social marketing or occupational safety and health professionals.

Jan 1, 2009

By Kenneth P. V. Lei

The Bureau of Mines investigated a silver-catalyzed oxidative procedure for leaching an arsenical copper sulfide concentrate containing 10 pct As and 32 pct Cu_ Currently, there are no environmentally safe means to treat arsenical copper concentrates in the United States. Leaching was conducted in a 2-L autoclave reactor. The effects of catalyst concentration, O2 pressure, temperature, and H2S04, Cu, As, and Fe concentrations in the leaching solution on extractions of metals from the concentrate were determined. The best leaching conditions for extracting 95 pet eu and As and less than 21 pct Fe were 260 g/L concentrate, 0.007 mol/L (1.0 g/L) AgCI, 3.0 mol/L (294 gIL) H2S04, 1000 C, 60 psig 02, and 6 h. Copper as CuS04-5H20 was recovered by crystallization from the pregnant solution. Arsenic, as AS203, was recovered from the copper mother liquor by solvent extraction, with tributyl phosphate, S02 reduction of As5+ to As3+ in the strip solution, and crystallization of the As3+. The silver catalyst was recovered by contacting the leached residue with a brine solution. A conceptual scheme is proposed for treating arsenical copper sulfide concentrates.

Jan 1, 1987

By John D. Foulkes

An investigation is made into whether commercially available equipment can be used to engineer effective emergency warning systems for underground coal mines. Discussions with members of the Bureau and the Mining Enforcement and Safety Administration established that the preferred system should operate over the existing Pager Phone twisted pair, and broadcast an audio alarm. Applicable equipments such as voice band tone signaling equipment, alarm sounding equipment, mine telephones and complete alarm systems from over thirty manufacturers are listed. Factors affecting the range over which an alarm could be detected in representative mine situations were studied. These included (a) the subjective masking effects of typical background noise found in mines, such as that due to continuous miners (b) the attenuation of sound in mines (using both a theoretical and experimental results) and (c) the attention-getting qualities of different sound for miners. Audio alarm systems meeting the requirements can be installed and representative systems are described.

Jan 1, 1977

By D. G. Collins

As part of its effort to develop ways to maximize resource recovery, the Bureau of Mines investigated the extraction of vanadium from Western phosphate beneficiation tailings with H2S04 and/or H3P04. Dissolution of the vanadium was accomplished by digesting a mixture of acid and a 50-pet-solids, tailings-water slurry. In the most effective method investigated, vanadium and phosphorus were leached by digesting the slurry at a constant boiling temperature (1000-1100 C) in a stirred reactor. In batch tests, maximum vanadium dissolution was 95 pet. In continuous-circuit tests designed to further evaluate vanadium dissolution at con-stant boiling temperature in a continuously stirred reactor, vanadium dissolution ranged from 70 to 85 pet. An economic evaluation of the process demonstrated that H2S04 consumption is the major cost factor. Based on the value of the vanadium product with no allowance for a phos-phate product, the cost of producing the V205 is more than twice its value. The potential for profit would depend upon the value of the phosphate fertilizer produced from the impure H3P04 remaining after vanadium extraction.

Jan 1, 1985

By Kenneth L. Kreamalmyer

"The demand for open-hearth iron ore and the existence of suitable smelting facilities in the St. Louis area seemed to warrant investigation of several Missouri iron-ore deposits of the filled-sink type. Preliminary examinations were made in the autumn of 1944 by an engineer3/ of the Bureau of Nines, and in December of the same year funds were allotted for the exploration of these properties by churn drilling. Three properties, the Silver Hollow Bank and the Newbauer and Coleman properties, were drilled. Work was completed May 8, 1945.The Federal Geological Survey and the Missouri Geological Survey and Water Resources assisted in the project by determining the stratigraphy from drill cuttings and by mapping the drilled areas.The properties explored are in the hilly section of east-central Missouri and are connected by all-weather graveled roads with various shipping points of the St. Louis-San Francisco Railway system within 3 to 6 miles of each property.The Silver Hollow Bank, in sec., 8, T, 40 N., R. l W. Franklin County, Missouri, is in the Meramec State Game Reserve. The nearest town and shipping point is Sullivan, Mo„ which is 6 miles distant. The Newbauer property, in sec. 28, T. 41 N., R, 2 W., Franklin County, Missouri, is approximately 3 miles west of Stanton; The Coleman property, in sec. 14, T. 38 N., R. 3 W., Crawford. County, Missouri, is within a short hauling distance of the railway at Elayer, Mb. These are shown on figure 1.The region surrounding the explored areas contains a series of low-lying hills or ridges and narrow winding valleys drained by the Meramec River system. These hills seldom rise more than 200 feet above the valley floors, most of which are approximately 700 feet above sea level. Except for numerous small farms and a few small towns, the entire region is covered by a dense growth of timber and small brush. The St. Louis-San Francisco Railway system, U. S. Highway 66, and numerous all-weather State and county roads traverse the area."

Oct 1, 1945

By C. W. Davis, M. W. Von Bernewitz, S. C. Lind

During the past few years our possible domestic resources of platinum have attracted much attention . On account of the extensive use of platinum during the World War , and the practical elimination of the Russian supply , the price of this metal rose to new high levels , as shown in Table 1 ; and though it since receded to some extent , the price is now nearly six times that of gold .

Jun 1, 1923

By R. Hogg, S. Chander

"An overview of various physical and interfacial characterization methods for use in mineral processing is presented in this paper. The availability of a large number of characterization techniques and commercial instruments requires that the reliability and limitation of each be carefully examined. The choice of a method may depend upon the manner in which the information is to be used, for example in development of new processes, plant and process design, plant control, problem solving, etc. IntroductionThe behavior of particulate systems, in mineral processing and other applications, is primarily affected by the physical characteristics (size, shape, surface area, pore structure) of the particles and the nature of the different solid-fluid interfaces present. Mineral processing operations in general are either designed to modify and/or control physical and interfacial properties (grinding, classification, agglomeration, etc.) or are strongly influenced by them (flotation, flocculation, solid/liquid separation, etc.). Characterization of physical and interfacial properties should be an integral part of the development of new processes, plant and process design, and routine plant operation.Our purpose in preparing this article has been to present an overview of the current status of characterization, to point out areas of weakness, and to discuss the reliability and limitations of the various techniques, procedures, and instrumentation available. For more detailed discussion of methods, etc., the reader is referred to standard references.Sampling particulate solids.Sampling is a critical factor in any procedure for characterizing particulate materials — the reliability of characterization data is ultimately limited by the extent to which the sample used was truly represen¬tative of the population from which it was taken.Sampling from particulate solids involves two basic problems: (1) the selection of a random', unbiased sample and (2) choice of the appropriate sample size.The problem of sample selection involves the design of a sample collection procedure that ensures that every kind of particle in the population has the proper chance of being included in the sample without bias. Specific procedures such as the well-known cone-and-quarter technique have been developed and are discussed at length in the literature on particle characterization (Allen, 1981: Herdan, 1960: Gy, 1982)."

Jan 1, 1989

By C. H. Riggs

THIS REPORT give's the results of a study of the central and south parts of the Cushing oilfield, including a description of the geology, a review of the production history, and estimates of oil reserves available by secondary-recovery methods. Each of the major producing zones of the field is treated separately. The report, which is one of a long series of field studies the Bureau of Mines has conducted over the past 40 years, was prepared to aid operators to increase oil recovery and to help prevent underground waste in the Cushing field, in the State of Oklahoma, and in the United States. The geology and production history are presented not as a review of past behavior of the Cushing field but rather to interpret the possibilities for increased oil recovery by future development of this and similar areas. The field, which is in the northwest corner of Creek County, Okla., was discovered in 1912 and developed during 1913 and 1914. For several years it, was one of the most important areas producing high-grade crude oil in Oklahoma. Although some oil has been recovered from each of 10 separate reservoirs, nearly 98 percent of the total recovery of oil in the area studied was from 4 major producing formations (table 1). Of these, only the Bartlesville [ ]

Jan 1, 1958

By Craig M. Jensen

A laboratory assessment of prompt and delayed neutron activation analysis with 252Cf and 14MeV neutron sources, for use as an in-situ method of determining low-level copper concentration has been performed. A simulated borehole using porphyry ore was constructed and varying copper concentrations were simulated using copper rods. Prompt neutron activation analysis experiments were consistant with earlier work and do not appear to be feasible fur copper concentration of 1.5% or less. Delayed neutron activation analysis experiments indicate that copper ore concentrations of less than 0.1% are detectable using either the 511-KeV gamma-ray of copper-64 or the 1039-KeV gamma-ray of copper-66, with high resolution detectors such as Ge (Li) or intrinsic germanium.

Jan 1, 1977

By S. Benedict Levin

The Big mine has been a source of mica and high-grade felspar from separate zones in the same pegmatite dike since 1914. In 1943 it became the outstanding producer of strategic mica in New England. The urgent need for sheet mica led to core-drilling by the Bureau of Mines from February to May 1914. Nine diamond-drill hob's aggregating 1,474 feet in length were drilled by the Bureau of Mines with the objective of developing extensions of the known mica shoots. The use of large-diameter bits made it feasible to obtain reasonably reliable results in diamond-drilling this type of deposit.

Jan 1, 1949

By William L. Porter

From the first day of new miner training until the day they retire, mine workers will experience changes due to the normal aging process. It is an unfortunate fact of life that many age-related changes result in diminished physical, sensory, or cognitive capabilities. Of course, workers also gain a tremendous wealth of experience, knowledge, and insight as they age, making them a vitally important resource for their company. Effective leveraging of this precious resource requires both an appreciation of the changes that occur with age and an understanding of methods that can be used to reduce the injury risk that may result. The purpose of this training is to provide the information necessary to accomplish these objectives. Aging workers may not necessarily have a higher injury risk overall; however, the effects of a musculoskeletal injury (MSI) on older workers may be more extreme. MSHA data show that not only does the percentage of MSIs increase when workers are over age 30, so does the number of days lost per injury, as shown in the graph below [MSHA 2005]. [ ] Protecting the safety and health of aging workers requires matching the demands of the job to worker capabilities. This means reducing or eliminating risk factors for injuries, such as heavy lifting, awkward postures, static postures, repetitive movements, and/or vibration exposures. In other cases, it may mean improving visibility or streamlining processes. Designing jobs to accommodate the changing capabilities of older workers will not only reduce injury risk for older workers, it will have the added benefit of protecting younger employees as well.

Jan 1, 2008

By H. A. Doerner

"During the year which has passed since the last progress report on reduction of zinc by natural gas,3 the laboratory experiments on this investigation have been completed. In this concluding report, the whole subject will be reviewed and additional data presented.Chemical ReactionsIn a thermodynamic study of zinc smelting, Maier 4 discussed the use of methane for reducing zinc oxide, and predicted equilibria at various temperatures for the sore important reactions. The study has been extended to include the following list.Maier predicted that 870°C. would be the critical temperature above which reaction (1) would take precedence over reaction (2) and that reaction (1) at equilibria would be substantially complete at or above 927°C. A subsequent papers described experimental verification of these predictions and gave data on reaction rates under various conditions.It methane is passed through a heated bed of zinc oxide at a low enough rate reactions (1), (3), and (4) reach an equilibrium which can be expressed by reaction (10). The equilibrium concentrations for the products of this reaction in the temperature range 900° to 1100°C. were calculated by applying the thermodynamic constants to the stoichiometric relations. 6 The results of these calculations are listed in table 1 and shown graphically in figures 1, A and B. These data have major importance, and experimental work has shown that they are subtantially correct."

Dec 1, 1934

By B. R. Mohal, F. F. Aplan, S. Chander

"The wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5] and to control the flotation, flocculation, filtration and flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series contains a linear hydrocarbon chain containing nine carbon atoms ( CH3 ( CH2 ) 8-C6H4-( OC2H4 )""' where n is the number of ethoxy groups). The octyl phenol series contains a branched hydrocarbon chain containing eight carbon atoms ( ( CH3 ) 3CCH2C ( CH3 ) 2-C6H4-( OC2H4)"").Initial wetting rates - modified Walker techniqueWalker et al. [ 6] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determined. This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7] to determine the effect of surfactants on wettability of cotton fibers."

Jan 1, 1989