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By R. R. Wells, G. M. Potter, A. O. Ipsen

This paper gives results of laboratory and pilot - plant investigations of concentration of western manganese ores during the Bureau of mines manganese-development program initiated in December 1940. The data summarize results obtained from laboratory investigation of concentration of ores from three properties in southeastern Arizona . The high - grade Gray - claims lot B ore , a product of hand sorting , is marketable directly or after sintering treatment . Intermediate - grade lot A selectively mined ore would be marketable after sintering as a plus 35 percent manganese produce , but gravity concentration methods were employed effectively to produce high - grade manganese concentrates with over 80 percent recoveries . Complex association of fine - grained manganese oxides , calcite , and fluorite in a siliceous ground mass limited the recovery of high-grade manganese concentrates obtainable from the low-grade Pyrolusite -group ore . A recovery of 63.7 percent of the manganese was made by flotation in a concentrate that sintered to plus 48 percent manganese grade . The low-grade Davis ore contains iron and manganese oxides too intimately associated to permit production of marketable manganese products . However , good rejection of calcite gangue was obtained by flotation , and the enriched manganese - iron product might have value as a spiegeleisen ore .

Feb 1, 1946

By W. W. Adams

Three hundred and twenty-eight mines and quarries, representing 36 States, took part in the twelfth yearly accident-prevention contest conducted by the United States Bureau of Mines and known as the National Safety Competition. Four underground mines and one open-cut mine (which represents the quarry and open-cut mine group), each the leader in its group, were awarded the ?Sentinels of Safety? trophy. Relative standing in the contest" was determined by the number of days lost from accidents in proportion to the total number of man-hours worked. Since 1925, when the National Safety Competition was inaugurated, an increasing interest has been taken in it by mining and quarrying companies as a means of stimulating mine and quarry safety by competition among similar plants. Each participating plant can, on a basis of its standing and record in the contest, determine to what extent its safety program is succeeding or to what extent it needs strengthening. With this information, each company that has a low standing in the contest can intensify its safety-promotion efforts the following year to obtain a lower rate and possibly win the trophy or achieve honorable mention in the competition. Except for 1929, the National Safety Competition of 1936 represented more man-hours of employment than any other year since the yearly contests began.

Jan 1, 1937

By S. M. Dar

The U.S. Bureau of Mines constructed a full-scale model of a 15-ft-wide coal mine entry to use in combination with finite-element analyses to investigate roof support systems and various types of roof bolts. The objective was to enhance understanding of the fundamental mechanics of the interaction between rock and supports and the relative integrity of bolted mine roof as a function of roof bolt type, length, spacing, and tension, and the basic characteristics of the roof strata. The laboratory test results, when correlated with computer simulations using fmite-element analysis and underground verification tests, should provide a basis for desigillng safer, more cost-effective roof control systems and help to establish guidelines for employing fully grouted resin and mechanically anchored bolting systems. The background for this research, the research approach, the methods and equipment employed, and the results are described in this report.

Jan 1, 1989

By P. G. Clites

This bulletin summarizes the results of Bureau of Mines research on the development of the inductoslag melting process. Inductoslag melting is an induction melting technique using a segmented, water-cooled, copper crucible. The process was developed as part of the Bureau's work on effective utilization of reactive metal scrap, and the process has been applied to melting Ti, Zr, Cr, Co, Fe, Ni, and V. Construction details are given for the segmented crucibles and for both an ingot furnace and a casting furnace. The melting process is described, and results of tests conducted with a variety of reactive metals are given.

Jan 1, 1982

By H. E. Powell

This study was made to determine the capabilities and limitations of the hydrocyclone for separating quartz sand from impure clays, Optimum operating conditions for beneficiating typical subgrade clays were determined. Estimates are furnished for installation and direct operating costs of hydrocyclones in such separations. Laboratory models of commercial hydrocyclones were used to beneficiate a suite of fire clays including plastic, semiflint, and flint types, all of which were contaminated with quartz in amounts ranging from 3 to more than 62 percent. Results show that this technique is not limited to a single type of clay but is applicable to clays ranging from plastic through flint, Under proper conditions use of this technique will result in good separation of the sand and good recovery of a useful clay mineral concentrate. Rejection of quartz from the clays investigated ranged from a low of 82.4 percent with an alumina recovery of 71.2 percent to a high of 99.0 percent with an alumina recovery of 85.6 percent.

Jan 1, 1963

By John W. Buch

At a meeting of the Anthracite Investigations Advisory Committee in July 1944 at Washington, D. C., the initial work and objectives of the Anthracite Mechanical Mining Section of the Federal Bureau of Mines were discussed. It was learned that interest existed in an improved performance of mining thin, steeply pitching beds above the gangway by mechanical methods. One company offered the use of one of its mines for experimental work, and this offer was accepted. Following acceptance, an effort was made by Bureau engineers to devise a mechanical method with a performance better than that of a new hand method proposed by company engineers for an actual mining condition. The method proposed by the Bureau was to drive 30-degree slant chutes across a 10-foot bed pitching 85 degrees. These chutes were to be advanced by using a lightweight, compressed air-powered, shearing machine of German origin that had been tried in a flat Pennsylvania anthracite bed in 1934, and which did not then prove successful because of blasting difficulties. An attempt was made to obtain one of these machines from England, where it was known machines of this type had been used. Shortly thereafter John W. Buch was sent to Europe as a member of the Solid Fuels Mission to the European Theater of Operations organized by the Technical Industrial Intelligence Committee of the Joint Chiefs of Staff. Through his efforts the Bureau of Mines obtained two such machines, known as the Eickhoff model DEK, one from England and one from Germany. This report covers the preliminary testing of these machines in order to obtain mechanical operating data for use in determining the power requirements for cutting anthracite with machines of this design.

Jan 1, 1949

By Jun Yi

In this paper, single-component gas sorption and transient diffusion processes are described within coal matrix exhibiting bimodal pore structure. The coal matrix is treated as a poroelastic medium manifesting swelling and shrinkage effects due to the sorption of gas under effective overburden stress. Gas transport is considered Fickian with molecular (bulk) and surface diffusion processes simultaneously taking place in the macro-and micropores of coal, respectively. The numerical formulation is intended to be explicit in nature to investigate the influences of sorption phenomena on the macropore volumes and on the overall gas transport for the cases of gas uptake by and release from coal. Results of the study show the presence of hysteresis during a sorption?desorption cycle of the gas. It is also found that the overall gas transport takes place at a rate significantly less than that in the macropores only. Thus the existence of a retardation effect in the overall gas transport is concluded. This retardation effect is primarily due to the micropore resistances, in particular gas adsorption, and is independent of the changes in the macropore volumes. It is shown that macroporosity of the coal matrix may change during gas transport due to combined effects of pressure and sorption-induced swelling or shrinkage of the coal. It is estimated that the macroporosity variation is non-uniform in space and time, as it is expected in reality, and typically taking values less than ±10 percent of the initial porosity.

Jan 1, 2009

By K. O. Bennington

The thermodynamic properties of aegirine, of composition [(Na0.869Fe30+7362 Fe20+16Mn0.03Ca0.1121)(A10.141Sil 9738)(06)], were experimentally determined at the Bureau of Mines as part of its efforts to advance minerals technology. The standard enthalpy of formation determined by hydrofluoric acid solution calorimetry is AHf298 = -641.12±0.73 kcal/mol. The standard enthalpy of formation from the oxides is AH298 = -37.136±0.509 kcal/mol. Low-temperature heat capacities were determined by adiabatic calorimetry from 19.1 to 304.6 K. The derived standard entropy is S298 = 38.03±0.14 cal/mol?K. The heat capacity was measured over the range 348 to 1,198 K by differential scanning calorimetry. These experimentally determined data were combined with data from the litera¬ture to calculate the Gibbs energies of formation and equilibrium constants of form¬ation over the temperature range of the measurements. Standard enthalpies of forma¬tion are given as functions of temperature. The standard Gibbs energy of formation at 298.15 K is AGf298 = -600.36 kcal/mol.

Jan 1, 1984

By Michael J. Magyar

The Federal Bureau of Mines has developed a hydrametallurgical method to recover aluminum, aluminum oxide, and fluxing salts from aluminum salt slags. The slag is leached with water at room temperature to produce a saturated brine slurry. Screening of the slurry yields an aluminum-rich fraction that can be returned to the dross furnace. The remaining slurry is vacuum filtered, yielding a clear brine solution and an aluminum oxide filter cake. Evaporation of the clear filtrate produces a high-purity fluxing salt for reuse in the dross furnace. Over 80 pct of the metallic aluminum is recovered in the aluminum-rich oversize fraction, while essentially all the fluxing salts are recovered by evaporation. This report contains the final results of an investigation on a process research unit scale, an economic evaluation of the method, and recommendations to further improve the process.

Jan 1, 1979

By J. W. Jensen

EXTENSIVE research and development was performed on the manganese-copper vibration-damping alloys to determine the relationship between the properties of the alloys and variations in composition, fabrication, Mid heat treatment. Mn-Cu alloys with unusually high specific damping capacity, 20 to 25 percent at a stress of 5,000 psi, have also the following useful properties: Tensile strength, 90,000 to 110,000 psi; yield strong, 60,000 to psi; elongation, 20 to 25 percent; hardness, 90 Rockwell B; and fatigue limit at, 28,000 to 30,000 psi. Both standard and special methods of testing were employed to obtain data on strength, modulus, hardness, resistivity, dilatation, micro-structure, crystal lattice, and damping capacity. The extensive tabular and graphical data on these properties are presented for alloys containing 50 to 85 percent as quenched d solution) and after various aging treatments. Expansion coefficients for all Mn-Cu solid solutions are graphed and a dilatometer study of contraction during aging is reported. Although high damping capacity is associated with aging to precipitate a-Mn from solid solution, with a cubic-tetragonal transformation and with the occurrence of antiferromagnetic ordering in Mn-Cu alloys, a tenable theory of the damping mechanism has not been reached.

Jan 1, 1965

By K. R. Dorman

To develop the potential of precast concrete sets as a support medium in underground mines, a three-piece precast concrete drift set was designed for a small opening and tested to destruction in an underground straining frame. Thirty-six tests were made with three sizes of members using three different loading conditions. In addition, 14 members were tested individually in the laboratory. Test results are compared with theoretical calculations. A cost comparison shows the use of concrete sets would be advantageous where conventional wooden timber requires excessive replacement.

Jan 1, 1968

By John W. Buch

Safety and cost in mining coal beds under the extreme pressures found at depth, full extraction to conserve resources, and even surface subsidence to minimize damage of improved areas have directed much well-deserved attention, in the United Kingdom; to roof-control methods. Because the effects of pressure will be felt intensely as our Pennsylvania anthracite mines grow deeper, the senior author took advantage of an opportunity afforded by a mission to Europe3/ to observe, to a limited extent, the effects of pressures found in deep mines and the manner in which they are con trolled. Organized research relating to strata control has been carried on in Great Britain for nearly 25 years. These activities have been ably outlined by Dr. D. W. Phillips.4/ Physical properties of coal-measure rocks, movements of roof and floor, and types of face and roadway supports have been investigated. Same of the forces induced by the extraction of coal have been measured. The results of this research have been publicized and openly discussed, and much progress has been made in establishing a better factual understanding of roof-control problems and their solution.

Jan 1, 1951

By W. H. Frederic, F. H. Gibson, R. F. Abernethy

This publication contains the quantitative values for phosphorus , chlorine , sodium , and potassium in United States coals . The samples tested were taken from commercial shipments and have been selected to represent the principal coal producing areas of the country . Due to combining the analytical results from two separate surveys , values for the four elements are not available for all samples .

Jan 1, 1965

By W. S. Sanner

Seven samples were analyzed from the major reserves of the Bottom Red Ash bed, Northern anthracite field. The data show variations in thickness and geo-logic structure and in the amount of coal that can be recovered. Recovery of market-grade (less than 17 percent ash) coal is high for all samples, ranging from 76 tp 95 percent in the 3-1/4-by 9/16-inch sizes. The occurrence of coal containing less than 5 percent ash varies from 19.5 to as much as 57.5 percent. Crushing the coarse sizes to minus 9/16 inch increased recovery of market-grade coal in six of seven bed samples. Crushing released sufficient impurities to cause substantial increases in yield of coal containing less than 5 percent ash for all samples. Analyses of the float coal indicate that the quality of coal is comparable for all samples.

Jan 1, 1967

By Edward E. Johnson

The Bureau of Mines publishes in its ?Minerals Yearbook? a series of indexes on the domestic minerals industry. Among these are the index of physical volume of mineral production, indexes of stocks, and indexes of average unit mine value and implicit unit value, This report describes the material coverage of these indexes and the methods used in their construction. Detailed descriptions are given for several other mineral-oriented indexes regularly published by other government agencies. These descriptions give the index user a better understanding of what each index purports to measure and aids him in selecting the most appropriate index for his purpose.

Jan 1, 1965

By Edward E. Johnson

The Bureau of 'Mines publishes in its ?Minerals Yearbook? a series of indexes on the domestic minerals industry. Among these are the index of physical volume of mineral production, indexes of stocks, and indexes of average unit mine value and implicit unit value, This report describes the material coverage of these indexes and the methods used in their construction. Detailed descriptions are given for several other mineral-oriented indexes regularly published by other government agencies. These descriptions give the index user a better understanding of what each index purports to measure and aids him in selecting the most appropriate index for his purpose.

Jan 1, 1965

By E. G. King

In continuation of the study of thermodynamic properties of the common interoxidic compounds of ferroalloy elements, this report gives the results of low-termperature heat-capacity measurements and entropy evaluations of the monotungstates of sodium, magnesium, and calcium. Previous reports4 5/ of this laboratory dealt with low-temperature heat capacities, entropies, and heats of formation of the sodium vanadates. Heat-capacity measurements of the monotungstates of sodium, magnesium, and calcium (Na2W04, MgW04, and CaW04) were conducted throughout the temperature range 51° to 298° K. The entropies at 298° K. were evaluated and then combined with entropy data for the elements and oxides to obtain entropies of formation. This information is an essential part of the data needed for thermodynamic appraisals of chemical reactions of these substances. No similar data for any tungstate are to be found in the literature.

Jan 1, 1961

By G. S. Rice, R. V. Wheeler

"FOREWORDThe cooperative mine safety research program was carried on successfully in the year 1930 in a manner similar to that described in the report for 1929It is believed that the results of such fundamental work as is being done are unquestionably of great benefit in their application in coal-mining operations, in the saving of life and health of minera. The research result compared and checked by investigations in the two organizations, and further by large-scale tests, as in the Experimental Mine, give confidence to mine operators, miners and State mining officials in the findings of the various researches.The annual report of the contact officers of the United. States Bureau of Mines and the British Safety in Mines Research Board to the Director of the Bureau and the Chairman of the Board respectively, follows:Annual Reports for 1930 To: The Director, Bureau of Mines.The Chairman, Safety in Mines Research Board."

Sep 1, 1931

By R. K. Koch

The vapor pressures of liquid columbium and liquid hafnium were deter-mined by the Langmuir free evaporation method as a part of the Bureau of Mines program on the study of transition metals. An electron-beam furnace with a water-cooled copper crucible was used for melting. Temperature was measured with a two-color ratio pyrometer. Least-squares analyses of the vapor pres-sure data gave the following equations: [Logp (atm) = 5 .429 -31,310 T] for liquid columbium in the range 2,740° - 3,140° K, and [Log p (atm) = 5,690 28 T] for liquid zirconium in the range 2,500° -2,810° K. Third-law evaluations of each data set gave mean heats of sublimation (298.15° K) of 175.1±3.2 kcal/mole and 148.3±1.2 kcal/mole for columbium and hafnium, respectively. Second-law standard heats of sublimation determined from sigma plots and from sigma-prime plots agreed fairly well with the third-law values. The sigma-prime plots gave standard entropies of sublimation of 30.96±0.84 eu and 33.S6±0.44 eu for columbium and hafnium, respectively.

Jan 1, 1968

By V. F. Parry

This report is the first substantial description of the carbonizing process and the details of experimental work conducted at the Denver laboratories under a coopeative agreement between the Bureau of Mines and the Texas Power & Light Co. It presents the results of tests on several Texas lignites and other typical western coals that have been processed in the first pilot plant operated at Denver. Investigations on drying fine coal in the entrained and fluidized state have been under way at Bureau of Mines Denver laboratories for several years. Reports on this work were published in 1949 and 19505/ describing the theory and practice of re-moving inherent moisture from the lower -rank coals. The investigation did not include a study of the removal of surface moisture from fine fuel. Private industry in Canada became interested in the possibilities of drying fine coal, employing the closed-circuit system and techniques recommended by the Bureau. Large, commercial-scale drying units were built by a Canadian company, which successfully demonstrated that surface moisture could be removed from fine coal at high efficiency and capacity ill drying units similar in design to those developed by the Bureau.

Jan 1, 1953