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By Gary R. Peterson

In order to determine the potential availability of alumina to feed U.S. aluminum smellers, the Bureau of Mines evaluated 39 domestic mines and deposits of bauxite, alunite, and high-alumina clays and found that substantial increases in alumina prices would be necessary before nonbauxitic deposits could become competitive with bauxite. As part of the study, a price-tonnage relationship was developed indicating the quantity of alumina that could be produced from known deposits at various alumina prices and at a 15-pct discounted cash flow rate of return on the required capital investment. All capital and operating costs were calculated in August 1980 dollars. The domestic bauxite reserve base comprises three operating bauxite mines in Arkansas containing some 15.6 million metric tons of recoverable alumina (A1203). Ferruginous bauxites, clays, and alunites fall into the subeconomic category of identified aluminum resources, which, at the demonstrated level, contain over 4,000 million metric tons of alumina that are estimated to be recoverable. Analyses indicate that, at the demonstrated resource level, a total of some 15.6 million metric tons of alumina, all from three active Arkansas bauxite mines, is recoverable at a 1980 price of $0.12 per pound ($264 per metric ton) of alumina. A price of approximately $0.26 per pound ($573 per metric ton) of alumina would be required for production of the total U.S. resource. Thus, unless new technological breakthroughs occur that could make alternate sources of alumina competitive with bauxite, U.S. dependence upon imported bauxite will continue to increase.

Jan 1, 1981

By E. Kamon

This report summarizes completed research pertaining to the reaction of human subjects exposed to Self-Contained Breathing Apparatus (SCBA) stressors during escape conditions (viz., resistance breathing, C02 breathing, hot air breathing, and static positive facepiece positive pressure breathing) and the development of an automated breathing and metabolic simulator (ABMS). Volume I contains summarizes of the studies performed under this contract. Volume II is an appendix which contains more detailed descriptions of these studies.

Jan 1, 1984

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in' the production of crashed stone. These studies, made at quarries situated in the eastern and southeastern parts of the United States, have not been completed, but to make results available to the industry as early as possible, it was decided to publish summarizes of the studies made to January 1, 1939, as a series of progress reports. The first of these dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The second, issued in September 1939 as Report of Investigations 3467, dealt with quarry haulage. The present report discusses analyses of time studies of primary drilling a t the same group of quarries. OBJECT OF STUDY Pressure of business problems frequently requires the entire attention of quarry management, and in consequence internal plant economies often are neglected. Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that technical studies at a number of plants, made by impartial engineers, might disclose opportunities to reduce costs or improve efficiency in internal plant processes.

Jan 1, 1940

By Peter W. Kauffman

This Bureau of Mines publication is designed primarily to provide mine engineers and production-level mine managers with the following: 1. Information to assist them in making the decision to retreat mine and in selecting the best retreat mining technique for specific mining conditions. 2. Information on mine planning that will enable them to design mine layouts for safe and efficient retreat mining. 3. Information that will enable them to develop a section foreman's handbook. The manual has been organized to gradually increase in level of detail as the reader progresses from beginning to end. Individuals interested in an overview of retreat mining can confine themselves to the first few chapters. Those interested in mine planning, should read the middle chapters as well. Those interested in the development of a foreman's handbook should read the entire manual.

Jan 1, 1981

By M. A. Trevits, A. Ozmet, A. C. Smith, J. B. Walsh, T. P. Mucho

Improvements in remote fire fighting technology are needed to reduce miner exposure to the dangers of fires and possibly save the lives of those who may become trapped. The National Institute for Occupational Safety and Health, in cooperation with U.S. Foam Technologies, Inc1., conducted a series of experiments at the NIOSH Lake Lynn Experimental Mine to study the stability, transport, control and fire extinguishing effectiveness of nitrogen-enhanced foam technology. This paper presents a description of the mine test configurations and experimental results

By W. R. Hardwick

This information circular describes mining methods and practices at New Cornelia Branch, Phelps Dodge Corp., Ajo, Ariz. It 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. The New Cornelia mine (fig. 1) is at Ajo, a town in southwestern Arizona (fig. 2) on Arizona State Highway 85 in the western part of Pima County. The [oncentrator] and smelter are near the mine (fig. 3). Copper ore is mined, crushed, ground, and concentrated, and the concentrates are smelted. Copper is cast in anode form and sent to the Phelps Dodge Corp. refinery in El Paso, Tex.

Jan 1, 1960

By Pamplinm J. W.

"INTRODUCTION For the past six years the United States Bureau of Mines in cooperation with the University of Alabama, Tuscaloosa, Ala., the Missouri School of Mines and Metallurgy, Rolla, Mo., and certain operating companies of the Florida land-pebble phosphate district have conducted an investigation to determine the amenability of phosphatic sands to concentration. 4 This paper discusses briefly an investigation of the concentration of fine phosphatic sanads of the land-pebble district of Florida. The process used - namely, the tabling of material previously given a selective oiling treatment - is new in its application to the phosphate industry, although old in principle.The feed to the standard phospidate washery is a hydraulically wined mixture of phosphate pebbles, quartz sand, and clay in which the quartz sand grains are segregated in the fine sizes. Me standard method of concentrating (washing) consists of wet-screening. at about 20 mesh to recover the plus 20-mesh material. 5 Lately some of the washeries have introduced hydraulic classifiers for sizing of the screen undersize to recover the coarser spigot products, but even this additional treatment allows much of the fine phosphate to be wasted."

Dec 1, 1932

By F. E. Diebold

The wastewater-treatment system of the Anaconda Mining Co., at its Butte, MT., operation has been physically and chemically characterize modeled on a computer and investigated with respect to alternate systems for economic heavy metal recovery. The system involves lime addition to a mixture of acid underground copper sulfide mine water, acid effluent water from the iron induced precipitation of copper from acid leach solution and basic suspensions of solid effluent from a concentrator plant. Experimental chemical analysis and predictive computer calculations shows that the monosulfllte and disulfllte complexes of transition metals (Iron II being dominant) and alkaline earths are 40% of the total dissolved metal load of both acid streams. The suspended solids (30% by weight) in the basic concentrator slurries are dominated by quartz and pyrite and also contain kaolinite muscovite, biotite and undissolved lime. The mixture of these three streams result's in major reductions in concentrations of Al, Cu, Fe, Mg, Mn, Sir and Zn, and a pH >7 with calcium, sodium, potassium, and sulfate being the major dissolved ions. The treatment system has been simulated in the laboratory and accurately modeled on a computer. The computer program, an altered REDEQL-EPAK, is capable of accurately predicting the amount of lime required to reach a desired effluent water. Preliminary research has indicated the usefulness of electroprecipitation as a means of recovering the valuable metal load and providing an EPA acceptable effluent.

Jan 1, 1982

By K. Zipf, Z. T. Bieniawski

"An extensive mixed-mode fracture toughness testing programme was conducted on coal from three coal fields. A special mixed-mode testing fixture for coal and other geologic materials was developed together with reliable specimen preparation procedures. Dynamic modulus measurements made on each of the 116 fracture toughness specimens showed that these coals exhibit certain degrees of anisotropy. The fracture toughness testing programme systematically varied the loading rate, specimen orientation and fracture loading mode. Loading rate did not significantly effect the fracture toughness over the quasi-static range tested. Orientation did have a significant effect on measured fracture toughness. In the coals tested, the divider orientation and arrester orientation had higher fracture toughness than the short transverse orientation. Data showed that one orientation could have almost twice the fracture toughness as another. The fracture toughness testing enabled certain evaluations of three mixed-mode fracture theories: maximum tangential stress, maximum energy release rate and strain energy density theory. Due to the extreme heterogeneity of the coals tested, definitive conclusions regarding the best mixed-mode fracture theory are not possible; however, data do tend to support the strain energy density theory. INTRODUCTIONThe major aim of this research is to ·develop a fundamental understanding of how fine· fragments of coal (respirable dust) are generated during a fracture process. In a related paper [l], a hypothesis was presented for the mechanism of fine fragment formation during a generic coal material/cutting tool interaction. In this hypothesis, fine fragments are created during coal material/cutting tool interactions that are best described as general mixed-mode fracture processes. Data are required on the mixed-mode fracture behaviour of coal, the physical character of the newly-created fracture surfaces and the character of the inherent flaw structure of the coal material. Accordingly, a test programme was designed that provided some information in each of these areas. The testing effort seeks to measure critical fracture toughness under mixed-mode loadings as a material parameter characterizing in part the tendency of various coals to generate undesirable quantities of fines and respirable dust."

Jan 1, 1990

By M. Beus, S. Inverson, B. Stewart

Abstract Recent ore pass failures have underlined the need for improved designs, standards, structural mon¬itoring methods and better hang-up prevention and removal tech¬niques. Researchers at the Spokane Research Laboratory of the Na¬tional Institute for Occupational Safety and Health (NIOSH) are investigating methods to improve safety during the transport of ore in ore passes. Design criteria and hang-up prevention and remedia¬tion strategies involve studies of the effects of static and dynamic ore and waste-rock loads on chutes, walls, gates and support structures. Particle flow analysis methods were used to simulate the response of various ore pass designs to a wide range of ore loading condi¬tions. A full-scale mockup of ac¬tual ore pass and chute assemblies was duplicated and tested for load response. Data from a particle flow code and the mock-ups were com¬pared Loads on an active ore pass chute were measured.

By Carl H. Beal

The oil industry in the United States is further advanced than in any other country, because of American initiative and the development of industries dependent in some way on petroleum or its products. For this reason the output has constantly increased (fig. 1), and as a result this country has produced more than half of the total output of the world. Trw total past output of the world is approximately 7,000,000,000 barrels of 42 gallons each; of this the United States produced about 4,000,000,000 barrels, or about 57 per cent. The limit of production in this country is being approached, however, and although new fields undoubtedly await discovery, the yearly outpnt must inevitably decline, because the maintenance of a given output each year necessitates the drilling of an increasing number of wells. Such an increase becomes impossible after a certain point is reached, not only because of a lack of acreage to be drilled, but because of the great number of wells that will ultimately have to be drilled. According to figure 1, the daily production per well each year has increased during the last few years. However, this increase is abnormal, being caused by the new pools brought in. Although such a condition may continue for several years, the average production per well will finally begin to decrease on account of the lack of new pools to make up for the normal decline in production of the old ones.

Jan 1, 1919

By William E. Young

There are many large rhodonite-bearing veins containing manganese in the Eureka-Animas Forks area of the San Juan Mountains in Colorado. The Sunnyside vein is the largest known vein in the area. As observed on the surface, the vein is mineralized over 8,000 feet and attains a maximum width of 200 feet. The average width of the vein and its branches and ramifications is 58 feet in the area that was mapped in detail. The weighted-average analysis of surface and underground samples from the northeastern extension of the Sunnyside vein is 8 percent manganese. Most other known veins in the area have a similar manganese content. The Hidden Treasure vein lies southeast of the Sunnyside-No Name-Mastadon vein. The weighted average of the analyses of surface and underground samples from this vein is 13 percent manganese. Exposures of the Scotia-Silver Chord vein are visible over a strike length of 4,000 feet on Treasure Mountain. Diamond-drill holes show that the vein contains 10 percent or more manganese to a depth of 400 feet. The vein has an average width of 28 feet. The Independence vein is exposed on the surface for a distance of 600 feet and has an average width of 6 feet. Three cut samples taken across the vein had an average content of 20.7 percent manganese. Sampling of the outcrops of eight veins in the Placer Gulch area also indicates manganese. Numerous other veins cropping out in the surrounding area are similar to the outcrop of the Sunnyside vein system mineralogically and are worth investigating.

Jan 1, 1966

By Kermit G. Davis, Sean Gallagher, William S. Marras, Kimberly Kovacs

This study evaluated spinal loads associated with lifting and hanging heavy mining cable in a variety of postures. This electrical cable can weigh up to 10 kg per metre and is often lifted in restricted spaces in underground coal mines. Seven male subjects performed eight cable lifting and hanging tasks, while trunk kinematic data and trunk muscle electromyograms (EMGs) were obtained. The eight tasks were combinations of four postures (standing, stooping kneeling on one knee, or kneeling on both knees) and two levels of cable load (0 N or 100 N load added to the existing cable weight). An EMG-assisted model was used to calculate forces and moments acting on the lumbar spine. A two-way split-plot ANOVA showed that increased load (p<0.05) and changes in lifting posture (p<0.05) independently affected trunk muscle recruitment and spinal loading. The increase in cable load resulted in higher EMG activity of all trunk muscles and increased axial and lateral bending moments on the spine (p < 0.05). Changes in posture caused more selective adjustments in muscle recruitment and affected the sagittal plane moment (p < 0.05). Despite the more selective nature of trunk EMG changes due to posture, the magnitude of changes in spinal loading was often quite dramatic. However, average compression values exceeded 3400 N for all cable lifting tasks.

By Clarke E. Schuetze

This project had as its objective the experimental investigation of water capsule production utilizing the Southwest Research Institute&apos;s submerged nozzle encapsulation apparatus (U.S. Patent 3,389,194). Initial efforts on this project involved nozzle configuration and shell formulation optimization. The shell formulation developed on a prior program was modified during the course of the project to obtain the best balance of capsule breakage resistance and water retention. Subsequent effort centered on determining operating conditions which would produce the best quality capsules for each candidate shell formulation as determined by laboratory tests. Some preliminary work was done to increase the production capacity of the encapsulation equipment. The program was extended with major emphasis concerned with scale-up studies of capsule production capacity and the treatment of problems associated with grouting cartridge fabrication. During the course of the program, water-containing capsules were produced which have good long-term water retention, block resistance and adequate strength. Using a single-nozzle design, a production capacity of 15.9kg (35 pounds) per hour was demonstrated to give acceptable capsules based on initial results.

Jan 1, 1978

By Thomas M. Barczak, Joe Bower, Jinsheng Chen

Pumpable roof supports provide an alternative longwall tailgate roof support and have grown in usage during the past few years. Heintzmann Corporation has been installing pumpable roof supports at the RAG Resources Emerald Mine in western PA since 1998, where they have provided effective roof control in their longwall tailgates. Despite the success of these supports in this application, questions remain regarding critical design issues for optimizing the use of this support technology. The support loading profile is characterized by a high initial stiffness with peak loading occurring at less than one inch of convergence, followed by significant load shedding with a post failure capacity comparable to that of wood cribbing. Therefore, the key to optimizing the support utilization is to provide sufficient load density to prevent convergence from occurring beyond the peak loading capacity. This requires an understanding of how the supports interact with the ground conditions, hence measurement of the ground reaction curve. In order to obtain this information, pumpable roof supports were instrumented to measure support loading. Roof deformation and roof-to-floor convergence measurements in the vicinity of the instrumented supports were also made. The experimental parameters for the installation were the support spacing and water-to-solids ratio of the grout, which controls the grout strength and ultimately the maximum capacity of the support. The study clearly shows that at this mine a 24-inch diameter support is fully capable of providing adequate ground control under depths of cover of 750 ft as only 50 pct of the available support capacity was utilized outby the longwall face. It was also shown that the 2.00 to 1 water-solids ratio, despite providing a slightly softer support response, is sufficient for maintaining the same degree of roof control provided by the traditional 1.75 to 1 grout mix. The 10-ft spacing of the supports did not cause any ground control problems outby the face. However, inby the face the performance of the support is degraded once the peak capacity of the supports is exceeded. It appears that the large load shedding behavior, which is characteristic of this support following peak loading, allows the immediate roof to separate. When this happens, the support is unable to regain control of the roof in time to prevent failure of the immediate roof beam.

By Theodore L. Turner

This Bureau of Mines report describes calcination of kaolinitic clay in a direct-fired 2-1/2- by 24-ft rotary kiln at 750° and 775° C. Methods for preparing kaolin feed materials and characterization of calcined products are discussed. Approximately 99 pct of the alumina in a typical eastern Georgia kaolin was soluble in HC1 after calcination at either 750° or 775° C.

Jan 1, 1982

By Raja V. Ramani

The potential usefulnuss of reclaimed surface-mined land has received much attention in recent times. This attention is partially due to the establishment of federal environmental reclamation standards but concern for achieving better land uses has also been shown by interested members of the mining industry. In an effort to develop a procedure for evaluating postmining land use potentials, specific mines in various regions of the U. S. were studied to determine the extent of current mined-land planning and to discover characteristics that are regional in nature. As part of this investigation, a 430-acre surface mine in Clear-field County, Pennsylvania has been studied. Established site planning principles have been applied to the case study site including formation of a data base, development of alternate land use plans, and evaluation of the economic, environmental, and social impacts of the land use alternatives. Key factors affecting site realization have been identified along with positive suggestions for applying land use planning processes to mined-land planning.

Jan 1, 1983

By E. D. Calvert

Molybdenum has been successfully cast into static and rotating molds in conventional equipment used for casting titanium and zirconium. Melting was accomplished by using an arc potential of 36 to 40 volts with a current of 10,000 amperes. Pouring efficiency, after a skull had been formed in the crucible, averaged 70 percent. Techniques are described by which four successful castings were made. Tensile properties on specimens cut from one centrifugally cast tube averaged: Tensile strength, 39,800 p.s.i.; yield strength (0.1 pct. offset), 35,300 p.s.i.; elongation, nil; reduction in area, nil; impact strength, 2 ft.-lb.; hardness DPH (diamond pyramid hardness) 180. Mold reaction was not evident in shapes cast in machined graphite. This was not true, however, for rammed graphitic-base molds.

Jan 1, 1960

By Gerald V. Gibbs

Quadratic functions, Q(hkl), are given to six places in increments of 0.01° for 2? from 0° to 90° for CuKa and from 25° to 180° for CuKa1. The wavelengths used for Cu in the computation are those agreed upon by the Editorial Commission of the International Tables for X-ray Crystallography (1950): CuKal 1.54051 A.; CuKa2 1.54433 A. INTRODUCTION At the Federal Bureau of Mines laboratory, Norris, Tenn., X-ray diffraction crystallography using tubes with copper targets revealed a need for a handy reference for the quadratic functions of copper radiation. The tables presented here were prepared to satisfy that need. The quadratic form Q(hkl) may be expressed in terms of the Bragg diffraction angle 2? and of the wavelength ? as

Jan 1, 1961

By Sabri Ergun

Cost estimates and technical feasibility are compared for six chemical coal cleaning technologies. The comparison is based on conceptual application of the chemical cleaning methods for removal of pyritic and organic sulfur from a utility grade bituminous coal. The process layout includes receipt of 8,000 tpd ROM coal, fine coal pulverizing, desulfurization, and preparation of a compacted clean coal suitable for storage and shipment. The methods are: the Magnex iron pentacarbonyl process, the KVB dry oxidation process, the Battelle hydrothermal caustic leaching precess, the TRW Meyers ferric ion leaching process, the Ledgemont oxygen/water leaching process, and the Bureau of Mines/Energy Research and Development Administration air/water leaching process. Capital costs estimated for the desulfurization operation alone, scaled to 8,000 tpd, range between $14 MM and $122 MM, while estimated operating costs for desulfurization alone on the same scale of operation range between $7 and $17 per ton clean coal produced. Relatively little is known about the chemical cleaning of coal, and present cost estimates indicate that the method might not be competitive at its present state of development when used alone to clean utility grade coals for sulfur removal. The principal attractiveness of chemical coal cleaning lies in its potential for combination with physical cleaning to produce cost competitive compliance coals in a combined process with high-Btu yields.

Jan 1, 1977