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By J. B. Clemmer

This report summarizes the results of u laboratory study of the beneficiation of Arkansas bauxite by flotation. Although the investigation is not yet completed, a preliminary retort of the results on several typical bauxites is presented to show the merits rind. limitations of flotation for the production of concentrates acceptable to the aluminum industry. It is

Jan 1, 1941

By J. B. Clemmer

This report summarizes the results of u laboratory study of the beneficiation of Arkansas bauxite by flotation. Although the investigation is not yet completed, a preliminary retort of the results on several typical bauxites is presented to show the merits rind limitations of flotation for the production of concentrates acceptable to the aluminum industry. It is

Jan 1, 1941

By James C. Barker

A uniquely mineralized area extends from northwestern Canada through Alaska into eastern Siberia. Some of the metals found there are relatively rare in the conterminous United Stales. Among these are cobalt, the platinum-group metals, and chromite. Geologic evidence suggests that cobalt and the platinum-group metals may be present in deposits that could constitute nationally important reserves. Chromite in potentially minable deposits is known, but it may be relatively less abundant. Limited reserves of these metals have been delineated, but most of the favorable terranes and reported occurrences throughout the vast expanse of Alaska remain unexplored. As part of the mineral studies mandated under the Alaska National Interest Lands Conservation Act, the Bureau of Mines' Alaska Field Operations Center and the Bureau's research centers at Albany, Oreg., and Reno, Nev., are cooperating in a long- range program to investigate occurrences and delineate reserves of cobalt, the platinum-group metals, and chromite in Alaska. Studies of other critical and strategic minerals will be phased in during succeeding years, as ongoing projects are completed. This first in a series of annual reports summarizes available information about deposits and past production of cobalt, the platinum-group metals, and chromite, and describes current and planned Bureau investigations of these minerals.

Jan 1, 1981

By J. B. Gayle

The merits of the various methods for dry-quenching coke have been the subject of numerous publications and almost equally numerous controversies for the past 40 years.5/ Most investigators have concluded that dry quenching is advantageous. Some have based their arguments on the improved physical properties of the resultant cokes. Others have claimed little or no improvement and have based their arguments on the economies acquired from the recovery and utilization of sensible heat. The extent to which the method of quenching influences the properties of the resultant cokes is of importance in connection with the operation of both commercial and experimental ovens. On the other hand, the recovery and utilization of sensible heat are economic problems related solely to commercial oven operation and- depend on the method of dry quenching used and the demand for a low intensity energy source. The scope of the present Bureau of Mines investigation has been limited to a comparative study of the properties of wet- and dry-quenched cokes produced from six coals and blends carbonized at flue temperatures of 2, 000° and 2,400° F. in the Tuscaloosa oven.

Jan 1, 1959

By George S. Rice

The major purpose of this bulletin, as indicated in the preface by Dr. John W. Finch, Director of the Bureau of Mines, is to give a critical review of the coal-mining methods used in the principal producing countries of Europe, to describe the reasons underlying the adoption of these methods, and to contrast them with coal-mining methods employed in the United States. The report includes discussions of various subjects intimately related to coal mining, such as geology of the principal coal fields; production and resources of the several countries; mine safety and health research; Government mining regulations; mine inspection and rescue procedure; safety lamps; fixed lighting methods under-ground; testing electric motors, mining machines, and mining explosives for permissibility; and special mining hazards, such as explosions of gas and coal dust, mine fires, instantaneous gas outbursts, ground movement and surface subsidence, and bumps. Commercial, economic, and labor problems of European coal mining, including miners' output, wages, and social-insurance schemes, as well as cost of mining, prices of coal, etc., are briefly described. It will be noted that data on most subjects are not given for Russia, which has become an important coal-producing country, owing to the lack of reliable published information concerning Russian coal mining.

Jan 1, 1939

By Arthur L. Murray

"INTRODUCTION In compliance with those provisions of the organic act establishing the Bureau. of Mines which relate to improvement of health conditions of persons engaged in the mining, preparation, or treatment of mineral substances, sanitary surveys have been made of towns and villages housing the coal miners, metal miners, and mill and smelter employees of Utah.The purpose of the surveys is to afford studies of conditions prevailing in the various mining and smelter towns so far as concerns housing, water supplies, sewage disposal, refuse disposal the handling of foodstuffs, general sanitation, wash and. change houses, and the control of preventable diseases, all of which directly or indirectly have a bearing on the health and efficiency of employees and their families. Certain other factors have been added to the general sanitary surveys such as school and recreational facilities, which have a decided influence on contentment and efficiency. Through comparisons of favorable and unfavorable conditions and practices, and the dissemination of such information, improvements can be effected which will benefit both the employees and the employers.ACKNOWLEGMENTSAcknowledgment is made of the many courtesies shown by the officials of companies and towns visited. In some instances the towns were entirely under the control of officials of mining companies, being on company property whereas, in other instances, the towns wars incorporated not under company management. Particular acknowledgment is made of the assistance given by the Utah State Board of Health through Health Commissioner Dr. T. B. Beatty."

Oct 1, 1932

Research personnel from the Bureau of Mines, a representative of the Mine Safety and Health Administration, and research contractors for the Bureau of Mines met with other Government and industry representatives at three seminar locations in December 1980 to discuss the findings and products of Bureau research on mine safety training. The research program is aimed at providing assistance to the mining community in its efforts to reduce industrial-type, human-error accidents through research establishing performance based methods and media for employee training. Research emphasis is directed toward development of baseline materials and instructional models; development of methods for structuring and evaluating health and safety, supervisory, and occupational training; and the continued investigation and application of current learning and simulation technology that could significantly enhance the effectiveness of training opportunities.

Jan 1, 1981

By Larman J. Heath

Wellbore enlargement was tested using hydrazine hydrate in a gas-storage well in Ohio to increase the well productivity. The wellbore was to be enlarged by chemical disaggregation of the sandstone adjacent to the wellbore. Productivity immediately declined 49.1 percent and gradually declined to zero in 7 months. A down-hole camera survey showed a white-to-gray precipitate covering the entire wellbore surface. The precipitate was chemically analyzed and identified as mostly carbazic acid, a hydrazine derivative of carbonic acid. Formation of this precipitate was not anticipated; this viscous sub-stance caused the gradual loss in productivity of the well. The wellbore was not enlarged. Laboratory tests were run to determine what clay stabilization measures could be taken in sandstone cores to prevent clay swelling and particle migration caused by hydrazine hydrate. Normal clay stabilization methods did not prevent the virtually complete loss in permeability to hydrazine hydrate. Other laboratory tests using natural gas diluted with small amounts of carbon dioxide confirmed the ease with which carbazic acid could be formed in a hydrazine hydrate-saturated environment within and adjacent to the wellbore.

Jan 1, 1970

By Warren E. Morrison

Stimulated by 4 years of continuous economic growth without inflation, demand for energy in the United States reached an alltime high in 1964. Total value of production of goods and services (gross national product--GNP) for the year was $629 billion, an increase of 6.8 percent from 1963. Allowing for price changes based on 1958 dollars, the gain in real terms was 5 percent. In 1964 the Federal Reserve Board Index of Industrial Production stood at 132, a rise of 6.2 percent. With the impetus provided by personal income and corporate tax reductions during the year, aggregate wages, profits, and consumption reached record levels. Even the persistent balance of payments problem improved. Against this background the national consumption of commercial energy increased 4.2 percent. Energy needs continued to be met largely from domestic resources with imports, mainly crude petroleum and refined petroleum products, accounting for but 7 percent of the total. Mineral energy resources, namely gas, coal, and petroleum, contributed 96 percent of the input of energy into the economy during the year. The remaining 4 percent came from hydropower and nuclear power.

Jan 1, 1965

By G. L. Oldwright, F. K. Shelton, W. E. Keck

"INTRODUCTION Zinc must be of high grade to satisfy the present demand. Even when the amount of premium paid is small, the purer metal as the buyers' preference. The following specifications for spelter were taken from the American Society for Testing Materials for 1927, Part I, pane 524. (The specifications for 1930, p. 582, are tile same.)Another specification for zinc of a much higher grade than any of the above has been established lately by the same society. The committee on zinc die-casting (Proc. Am. Soc. Test. Mat., vol. 31, 1931, p. 263) reached the following, conclusions: I. ""That the purest of zinc is necessary to produce stable zinc-base die castings, and as a result requested specifications for zinc spelter .with total impurities not over 0.02 percent."" Their tests showed that the die castings made of the purest zinc had the least elongation and the greatest tensile strength, and exhibited the least changes with temperature.Still more far-reaching claims are made for the properties of zinc containing over 99.99 percent metal. Zinc foil, for instance, may someday be made as a common commercial product. It would seem likely that the demand for zinc of high grades rill continue and that even purer varieties may be desired. This demand fits in with the modern trend in manufacturing plants of reducing the number of variables to a minimum by using pure materials, and of controlling the processing of metals during their various stages of fabrication by mechanical means instead of by expert laborers."

Jun 1, 1933

By A. C. Fieldner

"Decline of the Beehive Coke OvenTwenty years ago a favorite theme of the crusader for fuel conservation was the enormous waste of valuable by-products incurred in the manufacture of blast-furnace coke in beehive ovens. Indeed, there was good reason for arousing the national conscience to this needless' loss of an irreplaceable mineral resource. In 1910, 83 per cent of the coke production was made in beehive ovens, from which surplus gas, tar, light oil, and ammonia, aggregating in value (at 1910 prices) 40 million dollars annually, were discharged into the atmosphere.In 1929, proportions were reversed and 90 per cent of the production was made in by-product ovens. The average value of by-products obtained in the production of 1 ton of coke in 1929 was $3.60, as compared with $1.16 in 1910, although the value of a ton of coke had increased only from $3.47 to $4.80. As shown in Figure 1,1 the production of by-product coke progressed rather slowly until 1915. War needs suddenly expanded the demand for coke and the by-products benzol and toluol for the manufacture of explosives. Except during the depression of 1921, this accelerating rate of production was maintained up to 1929, largely at the expense of beehive plants. The 1929 production of 60 million tons of coke will probably remain a record-breaking figure for several years. The developments which are now in progress in long-distance transmission of rural gas and in the utilization of volatile petroleum products and refinery gases for augmenting, city gas supplies may retard an other- wise accelerating demand for coke and coke-oven gas for domestic and industrial heating, Trends in Value of By-ProductsThe increasing value of by-products in comparison to the value of coke is shown in Figure 2. In 1913, the average value of by-product coke was $3.38, the value of the by-products per ton of coke was $1.41, and the cost of coal per ton of coke was $3,27, In 1929 not shown in figure) the value of the coke had risen to $4.80 per ton, the value of the by-products to $3.60, and the cost of coal per ton of coke to $5.07. The by-product values in were 155 per cent higher than in 1913, although the coke value had increased only 25 per And the cost of the coal 55 per cent. Actually the increase or the total value of coke plus by-products in this period was very little more than the increase in the coat of the coal, being 55per cent for coal and 60 per cent for coke plus by-products."

Mar 1, 1931

By J. M. Stuve

The present Bureau of Mines investigation measured low-temperature heat capacities of NiBr2 (8 to 302 K) and NiS04 (9 to 70 K) by adiabatic calorimetry. The standard entropies (S°, 298.15 K) of NiBr2 and NiS04 were calculated as 29.26 ± 0.06 cal/deg mole and 24.21 0.04 cal/deg mole, respectively. (1 cal = 4.1840 joules.) Heat-of-solution measurements of anhydrous NiBr2 were used to determine its enthalpy of formation (?Hf°, 298.15 K) as -50.64 ± 0.31 kcal/mole. High-temperature enthalpies of NiBr2 and NiS04 were measured by drop calorimetry to 1,150 K and 1,002 K, respectively. Enthalpies, heat capacities, and related formation functions are tabulated to 1,200 K.

Jan 1, 1978

By Doris M. Hyde

Mineral output and trade in the Central American countries were directly or indirectly affected by the sometimes violent civil unrest and recessionary economic developments that have pervaded the region for several years. Central American countries found their foreign exchange export earnings and traditional market areas shrinking while essential import costs were rising. Restricted spending measures were adopted by governments and private industries. Domestic investment funds for mineral development and exploration projects were among the first casualties of these austere budgetary measures, especially since weak demand and depressed mineral prices diminished the probability of a favorable cost-benefit ratio. The lack of physical security and political stability also discouraged private foreign investment. The United States Congress enacted the Caribbean Basin Economic Recovery Act of 1983 (19 U.S.C. 2702), more popularly known as the Caribbean Basin Initiative (CBI). This legislation was designed to stimulate economic recovery and promote economic development by increasing private investment and trade in the Caribbean Basin countries. The act provided for the elimination of U.S. duties on most trade items imported directly from eligible Caribbean countries, provided at least 35% of the product value originated in the region. The financial assistance components of the CBI were to be supportive of the basin's private sector as well as assist general economic stabilization programs.

Jan 1, 1985

By Christopher Mark

The first International Conference on Ground Control in Mining opened with the topic of pillar design. Two classic papers were presented, one by Bieniwski and the other by Wilson. Unfortunately, the two methods were so radically different from each other that it was nearly impossible to reconcile them. Adding to the confusion were the many other pillar strength formulas (such as the Salamon-Munro, the Holland-Gaddy, and the Obert-Duvall, just to name a few) that were also available. Little wonder that discussions of pillar design in those days often ended with anguished cries of “but which formula is the right one?” The past 25 years have seen substantial progress in the science of coal pillar design. Indeed, one testament to the improvement is the relative scarcity of papers on the topic at recent Conferences. Two factors have been largely responsible for the progress that has been made. The first has been the collection of large data bases of actual case histories of pillar performance in a variety of settings, from shallow room-and-pillar mines through deep cover longwalls. These have made possible the development of empirical design procedures that are closely linked to real world experience. The second important factor is the development of sophisticated computer models that can accurately simulate pillar behavior and roof/pillar/floor interactions. Together, these two lines of research have led to a new understanding of pillar mechanics that identifies three modes of pillar failure: • Sudden, massive collapse, accompanied by airblast, for slender pillars (width/height<4) • Squeezing, or slow, non-violent failure, for most room and pillar applications (4<w/h<10) • Entry failure or bumps for deep cover and longwall applications (w/h>10) It is particularly satisfying that the insights gained from numerical models broadly support those obtained from the empirical studies. While far less controversial than in the past, pillar design problems continue to arise. One recent example is pillar design for highwall mining. NIOSH has just released a software package, called ARMPS-HWM, which employs a number of modern pillar design concepts. Since highwall mining web pillars are long and slender, the greatest danger is that of a sudden collapse. ARMPS-HWM suggests two possible prevention strategies, one which

By Maria I. De Rosa, Charles D. Litton

The National Institute for Occupational Safety and Health (NIOSH/PRL) conducted a series of large-scale experiments to evaluate the effectiveness of optical flame detectors, photoelectric smoke detectors, and combined ionization and photo­electric smoke detectors for rapidly detecting mining equipment cab fires. The detec­tor alarm times were then used to trigger the discharge of a fire inerting system inside the cab to suppress cab material fires. This paper discusses the types of fire detectors tested, the experiments that Were conducted, and the results that were obtained. Con-" elusions are that rapid detection of equipment cab fires can be achieved to trigger the discharge of a fire inerting system inside the cab to protect the operator in the cab.

By Rimas Pakalnis, Tom Brady, Lewis Martin

A major focus of ground control research presently being conducted by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is to incorporate weak rock masses (such as are associated with operations in the Carlin Trend in Nevada) into existing design relationships. The original database that led to most of the empirical design relationships presently employed in hard-rock mining was derived from fair-to-good-quality rock. In this study, the relationship between weak rock quality and opening design (nonentry/entry methods) is being investigated. The common factor in all mines is a weak back or wall. This work attempts to provide tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

By F. E. Brantley

Research was undertaken by the Bureau of Mines to assess the technical feasibility of smelting cement-copper precipitate in an electric furnace to produce commercial-grade copper. The blister-grade copper produced in smelting was refined by gaseous oxidation and reduction methods to rive a product equal in quality to fire-refined copper. The cement copper used in the study was typical of the material produced in commercial operations. The sample product was received in a partially oxidized state and analyzed 77.5 percent Cu, 3.4 percent Fe, 0.8 percent Pb, 0.05 percent Ni, 0.6 percent Sn, and 0.9 percent S. Smelting tests were made on the precipitate using laboratory-size induction and electric-arc furnaces. Three types of furnace linings were tested during, the investigation: Carbon, including graphite; clay-graphite; and silicon carbide. Although all proved satisfactory, either carbon or graphite was preferred because of their superior refractory properties and low permeability to molten copper. Copper recoveries in the induction and arc smelting tests averaged 92 percent in commercial-grade metal assaying 99.8 percent copper. Refining the molten copper by oxidation and gaseous reduction or by chlorine lancing increased the purity to plus 99.9 percent.

Jan 1, 1961

By Joan T. May

The Bureau of Mines conducted laboratory tests to evaluate the production of high-purity H3P04 by HCl digestion and solvent extraction. Both batch and bench-scale continuous tests were made. Western phosphate rock concentrates were acidulated with HCI, and the digestion liquors were processed by solvent extraction. Phosphoric acid was extracted with isoamyl alcohol and recovered from the organic extract by contact with an NH4F solution. This solution was fractionally distilled to yield high-purity H3P04. The raffinate from solvent extraction was treated with lime to precipitate CaF2, which was subjected to steam pyrolysis to generate HF. This method was successful in recovering 95 pet of the phosphate and 80 pct of the fluoride contained in the concentrates.

Jan 1, 1976

By L. W. Brandt

The Bureau of Mines, as part of its mission to effect pollution abatement, conducted research to study various means of dewatering Florida phosphatic clay wastes and reclaiming mined lands. The work was done in cooperation with 10 Florida phosphate companies. During this work, a novel technique to effectively dewater phosphatic clay wastes was developed. The solids contained in the clay waste slurry are slowly compressed by moving wire mesh screens through the system. In a typical application, the screens were moved downward, compressing solids ahead of the screens. The rate of movement of the screens is an important variable in the process. It is believed that the moving screens distort the gel structure of the phosphatic clay system and cause the release of water. Samples of 18 clay wastes, including a high-grade attapulgite from beneficiation plants of the Florida phosphate field, were studied using the method. Typical samples were concentrated from initial solids of 4.7 and 11.9 percent to 16.8 and 25.2 percent, respectively, in 3-1/2 days. The high-grade attapulgite sample was dewatered from 2.7 percent solids to 13 percent solids in the same period.

Jan 1, 1980

By V. A. Cammarota

In this report, the effects of anode-production variables, such as aggregate coke sizes, pitch binder content, and baking cycle, were investigated. A small alumina reduction cell proved effective in evaluating anodes prepared from commercial materials and from lignite coke and pitch. Compressive strength was found to be the physical property most significantly influenced, but it did not appear to affect anode consumption. Specific carbon consumption, that is, the ratio of carbon in the anodic gas to carbon theoretically oxidized at the anode, was used as an index of anode consumption. It was found that an anode made with lignite coke and commercial pitch was very low in consumption; however, anodes made completely from lignite but by a different fabrication method showed high consumption and anode deterioration. Microscopic examination of anodes after electrolysis showed evidence of higher consumption at low current densities, and was useful in judging overall anode quality. Based on the physical properties of the anodes and their consumption during electrolysis, lignite can be a suitable material for anodes, provided the proper fabrication conditions are used.

Jan 1, 1970