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By W. A. Grosh

The Piquette Mining and Milling Co, operates a zinc mine and concentrating mill in the Upper Mississippi Valley zinc-lead district near Tennyson, Wis. The principal ore mineral is zinc sulfide, which occurs in limestones and dolomites of the Decorah formation. Exploration in the district is by churn drilling from the surface. An adit at the base of the ore zone provides access to the mine. A room-and- pillar mining method with irregular pillars is used. Drilling is done with Jumbo-mounted drills. The broken ore is loaded by crawler-mounted front-end loaders into diesel-powered trucks for haulage direct to the mill.

Jan 1, 1959

By Ludwig Schmidt

This report, the second of a series, presents the results of laboratory corrosion studies which were made in connection with a one-year test on aluminum lease tanks conducted by the United States Bureau of Mines. Part I of the report contains the results of the field teats.5 The studies were made on an oil lease in a so-called "sour district," near Borger, Tag., where free hydrogen sulphide accompanied the production of oil, gas, and salt water. Steel tanks previously used on the lease had suffered severe corrosion, because steel is inherently susceptible to attack by hydrogen sulphide. Because of the high resistivity of aluminum to the action of hydrogen sulphide, it Was believed that this metal had promising possibilities as a material for the construction of lease tanks in "sour districts." The results of the one-year field teat proved that aluminum lease tanks will withstand corrosion by hydrogen sulphide, but it was found that aluminum was susceptible to attack by salt water, which was invariably present in certain portions of the tanks, and that hydrogen sulphide accelerated this salt-water corrosion in an indirect manner, as will be explained hereinafter. In order to study corrosion conditions encountered in the tanks during the test period, a laboratory was maintained at the site of the aluminum lease tanks.

Jan 1, 1931

This paper describes the sinking and lining of a 14 foot 6 inch finished diameter shaft down to and into the salt of a typical dome of the Gulf States region. The conditions and nature of the strata encountered divide the work into three distinct sections - that in (1) alluvial surface deposits, sunk through by open caisson methods, (2) water bearing rock, directly above the salt, and in (3) salt. ACKNOWLEDGMENT The writer wishes to acknowledge the cooperation of the sinking contractors, The Dravo Contracting Co. of Pittsburgh, Pa., through E. T. Gott, vice-president, in furnishing the data used in this paper.

Jan 1, 1932

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 Henry P. Cole

A series of studies are described that identify critical health and safety skills needed by underground coal miners for coping with mine emergencies. First aid and self-rescue and escape were selected as two broad performance domains that include many subordinate skills needed for preventing, recognizing, and coping with mine emergencies. The performance domains and their objectives were used to direct the development of simulation exercises that permit miners to experience mine emergencies in the safety of a training room. The exercises are based upon research with similar simulations for the training of flight crews and medical personnel in information gathering, judgment, and decision making skills. Exercise content is drawn from actual mine accident and disaster case studies. The exercises incorporate recent principles of cognitive psychology and instructional design. Initial studies in annual refresher training classes suggest the exercises are stimulating for miners and their instructors, easy to use and read, sufficiently complex and authentic to challenge experienced miners, and useful devices for both teaching and testing critical problem solving skills required for preventing and minimizing emergencies.

Jan 1, 1988

By A. F. Colombo, R. T. Sorensen, D. W. Frommer

The Bureau of Mines developed a flotation method for concentrating spiral tailing produced from pilot plant tests on the Champion mine ore fines . The feed material contained about 49 percent Fe and 15 percent SiO2 and was posed mostly of specular hematite , muscovite , and chlorite . Bench- scale , batch flotation research developed a reagent suite composed of tall oil - fatty acid , fuel oil , sulfuric acid , sodium fluoride , and sodium silicate for recovery of iron minerals in the froth product . Concentrate made with the reagent suite contained 87.3 percent of the iron and analyzed 65.6 percent Fe and 1.9 percent SiO2 . Continuous flotation tests were made with a nominal feed rate of 400 lb /hr , but without middling recirculation . Using nearly the same amount and complement of reagents as in the batch tests , three similar continuous tests gave concentrates averaging 63.9 percent Fe and 3.1 percent Sio while recovering about 86 percent of the iron .

Jan 1, 1964

By N. L. Wimmler

The Metaline mining district was examined in 1942 by Bureau of Mines engineers with the cooperation of geologists of the Federal Geological Survey. Because the demands of war production were rapidly depleting reserves in some of the older zinc-lead producing districts of the United States, it was decided that an attempt should be made to increase the proved or indicated ore reserves of the Metaline district. With this objective, certain areas to be explored by diamond drilling were selected. The Bureau of Mines began work on this program. January 15, 1943; work terminated September 8, 1945. Forty-five holes were drilled in seven areas, The holes ranged from 154 feet to 2,050 feet in length. Their combined length was 38,150 feet. Thirty-three of the holes were drilled in. the North Pend Oreille and the West Bella May areas.

Jan 1, 1949

By J. B. Zink, M. J. Peterson

A semiquantitative spectrochemical method was developed and applied to the analysis of ash of U.S. coals . A low- temperature ashing procedure was used to minimize the loss of volatile elements . The analytical procedure provides for the estimation of 68 elements including major , minor , and trace constituents . Standards for the trace elements were prepared in a synthetic base mixture that approximates the average composition of U.S. coal ashes . Excitation was achieved with a d- c arc , spectra were recorded photographically , and interpretation was made by visual comparison of spectra of unknowns with spectra of graded standards series . Thirty- six trace elements were found in the analysis of 900 samples . Details of the procedure are presented , including sample and standards preparation , excitation and exposure conditions , spectral lines used , and approximate limits of detectability .

Jan 1, 1964

By Joseph M. Singer

Ignition of hybrid coal dust - methane - air mixtures by hot- turbulent - pulsedgas jets was investigated . The turbulent jets were generated by explosions in a primary chamber of stoichiometric mixtures of methane , oxygen , and nitrogen . The hot - gas ignition apparatus provided an adjunct means of testing , on a small scale , the type of ignition that exists in large - scale galleries or in coal mines . = coal particle The temperature Ignition variables were channel diameter , channel length , size , fuel concentration , and temperature of the hot - gas jet . of the hot jet was varied by changing the oxygen indices ( OI ) of the primary explosion mixtures . Coal dust having approximately 37 percent volatile matter was used . 02 O2ટ + N₂ The hybrid coal dust - methane - air mixtures required higher jet temperatures ( higher oxygen indices ) for ignition than the single fuel component methane - air mixtures . Methane in air concentrations less than the lower flammable limit of methane could be ignited in the presence of coal dust if the jet temperatures were increased . A specific explosion transmission ( ignitability ) curve existed for each coal dust concentration . The total fuel concentrations at the lower limit of each ignition curve was always close to or greater than stoichiometric , indicating that not all the coal dust was involved in the ignition .

Jan 1, 1964

By William C. Cooley

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Jan 1, 1975

By Oliver Bowles

The use of fire as a source of heat was the first step from primitive existence toward modern civilization, and heat has performed functions of inestimable importance throughout the ensuing ages. The first commercial steam engine invented in 1698 demonstrated that heat was an important source of power, and heat has since become the motivating force for railroad trains and steamboats as well as for machines in multitudes of factories. Aside from its function of supplying power, heat is an agent of vast importance in chemical reactions and engineering processes. Because of the high temperature of steam under pressure, losses by radiation from boilers and pipes become excessive unless the radiating surfaces are covered with insulating materials. Insulation is important also for hot-water pipes and many other types of equipment from which heat may radiate. Radiation losses from heated surfaces increase rapidly

Jan 1, 1943

By R. J. Leary

The natural gas-air burner described in this report was designed and constructed to meet the thermal requirements of a convective process for heating steel scrap. This process involved downward combustion of natural gas with air, blending the combustion products with diluent air, and then passing this tempered stream of gases downward through a porous bed of steel scrap contained in the furnace chamber. The scrap would be heated to a temperature limited by the adiabatic flame temperature of the gas stream in a period that depended on the rate at which heat was supplied per unit of bed cross section. The temperature of the gas stream would be limited to that beyond which an objectionable degree of oxidation would occur; for carbon steel this limit had been found to vary from 1,900° to 2,100° F. with the superficial velocity of the gas stream. The productivity of the process was dependent on the rate of heat input per unit of furnace cross section; for the 3-foot-diameter experimental furnace an input of 680,000 B.t.u. per hour was desired. The burner described was designed to meet these conditions of temperature and heat input. It provided for three streams of entering gases: (1) A primary air-fuel mixture too rich to be combustible, that is, above the upper flammable limit; (2) secondary air for combustion of the primary mixture; and (3) tertiary air, principally for cooling the combustion products to the temperatures desired for process operation. Downward combustion of the primary and secondary streams occurred in a flame stabilized on an annular port, while tertiary air flowed in an annular path surrounding the port and also through an axial channel whose wall formed the inner ring of the annular port. This burner performed beyond the designed heat-input rates while producing stable flames, which were adjusted readily to the temperatures desired. Gas-stream temperatures were easily controlled to within 15° F. of the desired value by simple manual adjustment of the flow valves.

Jan 1, 1959

By Louis A. Panek

An improved centrifugal-testing apparatus has been designed and built in the Bureau of Mines laboratory at College Park, Md., which is unique in that it incorporates the use of resistance gages to measure directly the strains in a rotating model without testing it to failure. Owing to this feature, a more rapid testing method can be used; furthermore, model materials need not be restricted to those of the prototype. The behavior of any structure in which strains of significant magnitude are produced by its own weight may be studied in a small model subjected to simulated gravity loading. The model is rotated in a centrifuge to induce in it centrifugal forces, which, like the gravitational forces in the full-size structure, act on the volume elements and are proportional to the masses thereof. Centrifugal testing is, therefore, applicable to the design of mine openings and to the study of similar ground-control problems. It constitutes an experimental method for determining the state of strain in a structure for which analytical methods are excessively laborious or even impossible. In previous applications of centrifugal testing by other investigators, the models usually were tested to failure, and the analysis was made from-the type of break produced. The models were made of the same materials as the proto-type, and the test results were applied only to the particular prototype represented by the model. Beam deflections were measured from photographs of the rotating model, but no means was employed either to determine the actual distribution of stress in the model or to determine quantitatively the degree of restraint imposed on the ends of the loaded model beam, that is, to determine whether the loaded model behaved as a beam with rigidly fixed ends or as some other type of beam. With the apparatus described, it is possible to determine the state of strain, and thus the boundary conditions, in a rotating test model weighing up to 90 lb., which can be subjected to centrifugal forces up to about 2,600 times the force of gravity. The load-strain relationship, applicable directly to the prototype, can be determined from a Single model test. The test results can be presented as quantitative relations between the loads, strains, and dimensions and mechanical proper-ties of the structural members and can be applied to any prototype, whatever its component materials, that satisfies the similarity requirements.

Jan 1, 1952

By Harry H. Ku

In December 1975, a report entitled "An Evaluation of the Accuracy of the Coal Mine Dust Sampling Program Administered by the Department of Interior" [1] was prepared by the Analytical Chemistry Division of the National Bureau of Standards (NBS), in response to a request by Senator Harrison A. Williams. Chairman, Committee on Labor and Public Welfare. The report attempted to evaluate the adequacy of (1) the personal sampler unit used to measure the coal dust concentration in the mines, (2) the procedures used by the Department of Interior (DOI) to analyze the dust samples obtained from mine operators, and (3) any recent studies made by the Department or private industry concerning the coal dust sampling equipment. Recommendations in the report of NBS included continued research efforts by the appropriate organization to correct the personal sampler deficiencies and to consider the use of area or stationary samplers as a supplement to the personal samplers. Concurrent with the NBS report cited above, the General Accounting Office (GAO) also issued a report in December, 1975 [2], suggesting that improvements are still needed in coal mine dust sampling programs and procedures relating to penalty assessments and collections. Among recommendations made by GAO, the following paragraph specifically called for actions by the agencies involved:

Jan 1, 1979

By K. B. Rojiani

Surface mining activities disturb large tracts of land resulting in the potential for greatly increased downstream sediment loads. The Surface Mining Control and Reclamation Act of 1977 places increased emphasis on the protection of the environment from the adverse effects of surface mining operations. Surface mining activities must be planned to minimize disturbance to the hydrologic balance, erosion and sediment contributions to receiving streams. Sediment ponds must provide a sediment storage volume equal to the accumulated sediment volume from the drainage area as determined by the Universal Soil Loss Equation (USLE) or other empirical methods established by the regulatory authority. It has thus become extremely important for the mining industry to secure more accurate estimates of potential erosion losses and sediment yield. Accurate estimates of sediment yield are required for the planning, design and successful operation of sediment control systems such as detention ponds and other alternative control structures and for evaluating the effectiveness of land management practices. The principal soil loss prediction procedure available for use is the LISLE. The USLE procedure is inadequate for use in predicting soil loss from surface mine regions for a number of reasons. These include: 1. The USLE was developed to estimate average average annual loss from agricultural soils. It cannot predict accurately soil loss for specific storm events. In surface mine regions a major portion of the soil loss occurs during the initial six months to one year of active mining. Accurate estimates of soil loss over short periods are thus required for the design of control structures. 2. The slope length and gradient factors used in the USLE were obtained from data or cropland having slopes ranging

Jan 1, 1983

By Jalna R. Zatko

Coal-clay waste slurries were dewatered in laboratory-and small-scale continuous tests by the Bureau of Mines using polyethylene oxide (PEO) as a flocculant. Dewatering from a nominal 7-wt-pct solids to over 50-wt-pct solids was accomplished using 0.5 lb of PEO per ton of feed in small-scale continuous tests. Parameters such as pH, initial solids content, and PEO concentrations were investigated. Water recovered from dewatering was reused as dilutant for PEO solutions.

Jan 1, 1982

By Seth T. Reese

THE INJURY DATA and experience at coal mines in the United States for 1949 are presented in this bulletin under the following general sections: (A) General injury experience: 1. Tables 1 to 18: Contain current data on number of injuries, frequency and severity rates, average severity, major and detailed classification of injuries, and distribution of injuries by part of body and days of disability. (B) Selected injury data: 1. Tables 19 to 45: Contain current data on various selected factors of operating and physical conditions that have contributed to the occurrence of injuries at bituminous-coal mines and at Pennsylvania anthracite mines. These factors include extent of hand and machine loading, size of mine by employment and production groups, thickness of bed or vein, duration and number of work shifts, rating of mine as gassy, or nongassy, types of cap lamps, ventilation, explosives, and combinations of factors that influence mine safety. (C) Injury experience by States: 1. Tables 46 to 52: Contain current data on number of injuries, frequency and severity rates, average severity, major classification of injuries, injury records of all coal-producing States, and the relative standing by States according to injury-frequency rates. (D) Appendix: 1. Tables 53 to 84: Contain certain injury data for the years 1943-47 that have not heretofore been published.

Jan 1, 1953

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 Charles L. Kimbell

In 1990, the aggregate value of world international export trade in mineral commodities was estimated at more than $64 billion in current (1990) dollars, about 8.4% higher than that in 1989, but still 8.7% below the record high set in 1980. Table 8 provides a data series for the estimated value of world export trade in all mineral commodities from 1979 through 1990, as well as a breakdown of this total into fuel and nonfuel commodities. It is noteworthy that for this 1990 edition, trade data for the year of review were available in time for inclusion, whereas in previous editions, the latest available global trade data were for the year prior to the year of review. Hence, as regards trade, this edition of Minerals in the World Economy updates the 1989 edition by 2 years rather than by only 1. For this reason, it is appropriate to note that the 1989 global total value for inter-national export trade in mineral commodities was almost $596 billion, 11.1 % above the revised 1988 level of more than $536 billion, both figures expressed in current dollars for the appropriate year. Despite the considerable increase in the dollar value of mineral commodity exports, their share of total export merchandise trade declined to 19.1 % in 1990 from 19.7% in 1989. At 19.1%, this share was very near the recent year record low of 19.0% reached in 1988. The year 1990 was the fourth in a row in which the total value of world mineral commodity export trade increased.

Jan 1, 1993

By S. J. Gasior

Pilot plant studies showed the technical feasibility of fluidized-bed operation for producing hydrogen and synthesis gas by the steam-iron process. A mixture of iron and iron oxide from 20-to 100-mesh was partially reduced with a simulated producer gas and then oxidized with steam and/or carbon dioxide. Results of tests show the effects of pressure, temperature, bed height, gas-to-solids ratio, type of iron oxide, and composition of gas on the gas and solids conversions during reduction and oxidation. A baffled free-fall solids system was also found operable. The short residence time of about 5 seconds limited conversion of the solids.

Jan 1, 1961