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By M. R. Geer

This report presents the results of washability examinations of seven coals from the principal coal-producing fields of Montana. A complete performance test of the Baum-type jig operated at one of the mines is included, as are the results of cleaning tests made on two of the coals in a dense-medium pilot plant. The coals examined from the Red Lodge, Bull Mountain, and Forsyth fields are comparatively easy to clean. Ash contents of 5 to 10 percent can be obtained at yields of washed coal ranging from 90 to 95 percent. The coal from the Great Falls field, however, could not be cleaned readily to less than 14 percent ash, and the rejection of impurity would amount to over 25 percent. The two coals treated in the dense-medium pilot plant were characterized by sharp separation of impurity, high recovery efficiency, and satisfactory reduction in ash content.

Jan 1, 1955

By J. H. Holden, G. R. Strimbeck, L. F. Willmott, W. R. Huff

A pilot - scale fluidized feeder was developed for continuously feeding up to 1 ton of pulverized coal per hour to a pressure gasifier . Fluidization in the 3 - foot - diameter by 34-1 / 2 - foot - high feeder is effected by two streams of inert gas , a technique called zone fluidization . A stream of inert gas through a drilled plate in the base of a central column near the bottom of the feeder fluidizes the coal . Another stream through a drilled plate in the annulus between the central column and feeder wall provides a source of semifluidized coal for the central column . Fluidized coal from the central column discharges through an extraction funnel and discharge line . Zone fluidization provided good fluidization with moderate requirement for fluidizing gas . Instruments were developed for metering and recording the flow rate of fluidized coal . A system was developed for storing , and weighing pulverized coal , and then delivering it in fluidized form at about 1 to 8 tons per hour .

Jan 1, 1964

By Oliver Bowles

Limestone, including dolomite, is the most widely used of all rocks - nearly 300 million tons annually in the United States alone. It occurs in some form in every State and is produced in thousands of localities. Because of its attractiveness, substantiality, and durability it is employed extensively as a building stone. In crushed and broken form it is used for concrete aggregate and railroad ballast and in highway construction, metallurgy, agriculture, and a host of chemical and industrial processes. This paper proposes to furnish general information on the origin and occurrence of limestone and dolomite, chief production centers, major uses, and methods of quarrying and preparing stone for market. Footnote references will guide the reader to sources of more complete information.

Jan 1, 1956

By L. Keith Hudson

The purpose of this study is to provide data that demonstrates that the Alcoa flash calciner design can be used for the decomposition of AlCl3?6H2O to A1203. Heat and material valance data for calcination provides data on the partial pressure of HCl in the off-gases. Experimentally determined data for the HCl partial pressure, over solutions expected in producing alumina from clay by the hydrochloric acid process, show that HCl can be absorbed from the off-gases into process solutions to effect crystallization of AlCl3?6H2O.

Jan 1, 1979

By R. E. Cumings

The Bureau of Mines made electrorefining tests in inert-atmosphere, molten salt cells to develop methods for the preparation of high-purity molybdenum. Seven of the electrolytes investigated were suitable for the preparation of refined metal. The electrolytes were composed of molybdenum chloride in alkali chlorides or mixtures of alkali and alkaline-earth chlorides. An electrolyte composed of potassium chloride and potassium hexachloro-molybdate was selected for a larger scale, more detailed study on the basis of its ease of preparation, its ability to retain the molybdenum salt, and the type of deposits obtained. High-purity molybdenum in the 99.99-percent-purity range was successfully prepared as dense plate up to 80 mils thick and as dendritic crystals. The temperature of electrolysis and the current density were major factors in determining whether plate or dendritic crystals of molybdenum were obtained.

Jan 1, 1966

By Manuel Gomez

A lignite from Milam County, Tex., has been oxidized by air at temperatures from about 27° to 300° C. for varying lengths of time. The oxidized coal was carbonized at 500° C. in a laboratory assay unit, and the products of carbonization were measured and analyzed. The data presented suggest that, as lignite is progressively oxidized, tar yields are decreased and gas yields are increased in a ratio approximating 1:1. It is surmised that tar-yielding structures in the nonoxidized coal produce gas, principally, when the coal is oxidized. Char-yielding structures of the nonoxidized coal give rise to additional water of decomposition after oxidation and pyrolysis. As lignite is subjected to greater oxidation, the gaseous product evolved on pyrolysis becomes almost entirely carbon dioxide. Tar yields decrease with an increased degree of oxidation, so that the reduction in tar yield may be used as a qualitative measure of oxidation. Pilot-plant drying and carbonization, where air is used as the transport gas and where some air is included in the drying and carbonizing gases, induces some oxidation of the coal particle. The short residence time in a fluidized system with reference to the oxidation environment limits the oxidation.

Jan 1, 1956

By John W. Frey

This paper presents one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the mining law of Australia was first compiled from the best information available in Washington; it was then sent to the American Consulate General , in Australia, where through the direction of Thomas H. Robinson , American consul in charge , it was submitted for criticism to the mining authorities in the various States of Australia , whose suggestions have been incorporated in this digest .

Sep 1, 1930

By Fred D. DeVaney

The Mesabi iron district of Minnesota has a potential production of over 50 million tons of iron are annually. The large shipments of ore each year are gradually depleting the reserves, and if the present rate of production is to be maintained there must be a growth in the present available ore supply. Growth is a natural course. The growth of a city may be affected by the addition of city blocks or by the improvement of utilities necessary for its betterment. These may go on in the order named or concurrently. The city-block type of growth of the Mesabi has been tremendous, and the "betterment" type has followed in due course. Probably the former has reached its limit, and if so, more time will be allotted to the latter. It is not the in¬tent of this paper to present either a eulogy of the wonderful mining methods or a history of the milling, but it is pertinent to say that if the lean-ore area continues to produce, the continuance will be more the result of further improvement of milling methods non well under way than of extension of boundaries by the city block plan of growth.

Jan 1, 1932

By J. D. Davis

"Introduction.Sixty years ago, M. Berthelot found that ethylene could be selectively absorbed from gaseous mixtures by concentrated sulphuric acid, and that the compound formed by the chemical union of the gas and acid was readily decomposed by heating with water, yielding ethyl alcohol. Only within the last few years has there been any attempt to make use of this discovery technically.Bury*, working in England at the Skinningrove Iron Works and on a commercial scale, developed a technical method for converting, the ethylene of coke-oven as into alcohol. With a gas containing less than 3 per cent of ethylene, he obtained a yield of 1.6 gallons of alcohol per ton of coal carbonized.De Loisy** perfected a technical method for treatment of coke-oven as for alcohol. Evidently this work was carried out on a semi-commercial scale. His method is based on the use of catalytic agents for hastening the absorption of ethylene by sulphuric acid. He uses part of the spent acid for drying the gases and pact for the manufacture of ammonium sulphate. Excess acid is reconcentrated by waste heat. Others have worked on the problem, but so far there has been no large recovery of ethylene from coke-oven gases. The chief difficulty seems to lie in the low efficiency (about 50% of methods and tae relatively low concentrations of ethylene in the gases treated. Gas from Trent amalgam*** contains much larger percantages of ethylene than does coke-oven gas, as Will presently be shown, and if it should ever prove practIcal to treat industrial ;as for alcohol, this gas would offer attractive possibilities,* Bury, Ernest, Ethylene as Alcohol from Coke-Oven Gas: Gas Journal' Vol. 148, D. 30, 1919, pp. 718.** DC Loisy, M.E., Sur un procede' industrial de fabrication syntlotique de l'alcool et de l'ether a partir des gaz de distillation de la houil Comp Rend, vol. 170, Jan. 1920, p. 50-3.*** A paste consisting of approximately part oil such as that obtained as for cleaning coal. See Perrott. in cleaning coal, Chem 3 parts finely pulvarized coal and 1 final product in the Trent, process StJ, and Kinney, S.P. The use of oil Vol. 35 August 3, 1921, p, 183.. & Met."

Nov 1, 1922

By D. C. Dahlin

To identify and characterize potential domestic chromium resources, the Bureau of Mines investigated podifom chromite deposits along the Border Ranges Fault in southern Alaska. Part 1 of this two-part report describes an extensive field investigation and preliminary resource evaluation studies by the Bureau's Alaska Field Operations Center. This paper, part 2, describes the mineralogy of 38 samples that were collected from low-grade deposits in the Chugach Mountains, on the Kenai Peninsula, and on Kodiak Island, and presents the results of laboratory batch beneficiation tests designed to concentrate the chromite. The samples are peridotites and chromites that consist primarily of variable amounts of chromite, olivine, and serpentine. They were beneficiated by a sequence of grinding, sizing, and gravity concentration operations. Twenty-four high-chromium or marginal high-chromium chromite concentrates, six high-iron or marginal high-iron chromite concentrates, and five submarginal concentrates were produced with chromium recoveries that ranged from 37 to 95 pct. Three very low-grade samples were not beneficiated. These results indicate that several of the de- posits may be significant chromium resources, Potential precious metals association with the chromite was also investigated. Analysis of these samples indicates that the chromite deposits are not good platinum sources.

Jan 1, 1985

By S. R. Droes

The U.S. Bureau of Mines investigated calcium fluoride (CaF2) assisted sulfuric acid (H2S04) leaching as an alternative to the melting-quenching procedure to obtain Mn from domestic manganese silicate resources. Pyroxmangite [(Mn, Fe) Si03] ore containing, in percent, 34.4 Mn, 22.8 Si, 2.6 Ca, and 1.3 Fe was leached in a 500-mL resin kettle. Ninety-six percent of the Mn was extracted under conditions of 330 g/L ore, 245 g/L H2S04, 35 g/L CaF2, 90' C, and 2 h. To incorporate electrowinning in recovering Mn, the ore was leached with a simulated spent anolyte solution containing, in grams per liter, 12 Mn, 140 H2S04, 130 (NH4)2S04 (ammonium sulfate), and 5 CaF2. Manganese extraction of 92 pct was achieved from 130 giL ore leached at 90° C in 3 h. The Fe, silica (SiOJ, and other impurities were precipitated from the pregnant solution by neutralization with ammonia (NH3). Manganese of greater than 99-pct purity was deposited at a cathode current density of 50 mA/ cm2 at 30° C, with a current efficiency of 65 pet in a two-compartment cell. A flowsheet was proposed for the leaching and electrowinning procedure.

Jan 1, 1990

By W. L. Falke

Research was conducted to develop methods on a laboratory scale for recovering manganese from manganiferous slimes and limestones . The procedure is a low- temperature modification of the carbamate process , in which manganese is dissolved and the valence reduced by treating slimes and limestones with controlled amounts of sulfurous acid . Manganese ( II) hydroxide is precipitated and leached with ammonium carbamate solution , and manganese carbonate is separated by warming the leach solution . A major portion of the reagents is regenerated and recirculated . About 75 percent of the total manganese in manganiferous slimes , and from 50 to 75 percent of the total manganese in manganiferous limestones , are recovered as manganese carbonate containing 45 percent manganese .

Jan 1, 1964

By W. C. Phalan

"Prewar Conditions:Metallic magnesium may be considered a war metal, but a war metal with a future, so far as the industry in the United States is concerned. Its production in the United States prior to 1915, on a commercial scale, was negligible, but imports prior to that year may be taken as a gaze of the demand for the metal. Unfortunately, magnesium was not listed separately by the Department of Commerce prior to the war, among the importations, but was included with other metals, as follows: ""Barium, calcium, magnesium, sodium, and potassium, and alloys of which said metals are the component materials of chief value."" However, the imports of metals enumerated other than magnesium were probably small, so that the importations under the above caption may be considered chiefly metallic magnesium in one form or another and, therefore, is an approximate gage of the demand for the metal in the United States. These imports were as follows:These figures are so close that they give a good idea of the figures for the respective calendar years.Of this prewar use, it has been estimated that about 85 per cent was used annually and in approximately equal quantities in the production of (1) flash-light powder, (2) fire works, (3) aluminum casting work, and (4) nickel and nickel-copper alleys, such as monel metal, etc. The re¬maining 15 per cent was employed for general uses, such as deoxiding brass and other copper alloys in foundry work, and to a small extent in laboratory and research work."

May 1, 1920

By James S. Browning

For the past several years, the Bureau of Mines has conducted laboratory and continuous process development work on weathered mica pegmatites and micaceous schist ores to determine the feasibility of recovering commercial-grade mica concentrates by flotation. The research has resulted in the development of two processes for flotadon of mica: an acid cationic method for recovery of coarse mica, and an alkaline anionic-cationic method for recovery of fine mica. The research indicated that the two processes may be effectively utilized separately or in combination for flotation of mica from weathered pegmatites and micaceous schists. Concentrates containing over 98 percent mica, with recoveries ranging from 77 to 92 percent, were obtained from the pegmatite ores. The micaceous schist ores yielded concentrates containing 95 to 98 percent mica, with recoveries ranging from 70 to 83 percent. Part 1 of this report summarizes the process development work and demonstrates the feasibility of producing commercial- grade mica concentrates. The report also includes details of commercial beneficiation and grinding of .mica.

Jan 1, 1973

By Alla D. Mah

The heats of combustion of three chromium carbides, Cr23C6, Cr7C3, and Cr3C2, were determined by combustion calorimetry. Heats of formation calculated from the results follow: ?Hf°298 (Cr23C6) = -94.7 ± 5.0 kcal/mole, ?Hf°298 (Cr7C3) = -43.3 ± 1.7 kcal/mole, and ?Hf°298 (Cr3C2) = -22.5 ± 0.8 kcal/mole.

Jan 1, 1969

By F. W. Wood

A program of research was conducted by the Bureau of Mines to investigate anomalies in electrical-discharge behavior during consumable-electrode arc melting of titanium and to study the effects of these irregularities on arc-furnace explosions. A major effort was devoted to an experimental survey of arc behavior and a qualitative definition of discharge phenomena.3/ An important conclusion was that the "glow" of industrial arc-melting terminology is not a glow discharge but a skittering arc in a displaced position. The conditions that permit displaced skittering were tentatively defined. The displaced skittering arcs tended to damage melting crucibles in two ways, and details of possible mechanisms leading to crucible rupture and explosive reactions have been proposed accordingly. However, no acceptable means of preventing crucible damage was discovered.

Jan 1, 1961

By J. H. Stears

Increasing use of Birmingham and other roof trusses prompted a Bureau of Mines study of support forces produced on a mine roof by these members. Equations, obtained from laboratory and field tests, are given for calculating the contact forces between the roof strata and a typical truss. Actual contact forces for a specific truss are difficult to estimate because of variable friction loss at the contact points. A finite-element analysis, using typical contact forces, indicated that trusses have a negligible effect on the stress field in massive, competent roof strata. The effectiveness of trusses in supporting broken rock strata was not analyzed. However, experience has shown that trusses are effective in supporting incompetent roof.

Jan 1, 1988

By William H. King

The Nevada Massachusetts tungsten deposits (fig. 1) are in the Mill City Mining District in north-central Pershing County, Nev., about 37 miles southwest of Winnemucca. Contact metamorphism of thin limestone beds within a series of metamorphosed sedimentaries formed scheelite-bearing ore bodies. These deposits are distributed over a wide area. A Bureau of Mines development program was started January 11 d was completed on July 25, 1941. This work was centered on the outer and less explored beds in the district and comprised trenching, sampling, and diamond drilling. Exploratory work was done in cooperation with the U.S. Geological Survey. Project work substantially increased the reserve tonnage of marginal ore in three of the areas explored and proved the nonexistence of tungsten in a fourth area. The following pages summarize the history of the district, outline property ownership, and describe physical features and ore deposits. The plan and results of the work performed by the Bureau of Mines are presented along with geologic and topographic maps, assay maps, and diamond drill-hole logs.

Jan 1, 1950

By R. L. Lincoln

The effects of adding from 1 to 50 atomic percent (a/o) to vanadium were investigated by the Bureau of Mines. Properties studied included as-cast and annealed hardness, microstructure, fabricability at room temperature and elevated temperature, tensile strength, electrical resistivity, and oxidation resistance at 625° and 800° 2. Additions of small amounts of hafnium resulted in lessened as-cast hardness, decreased electrical resistivity, impaired roll- ability, increased oxidation resistance, and greater tensile strength. Larger amount of hafnium caused greater as-cast hardness, increased electrical resistivity, further impaired rollability, continued increase in oxidation resistance, and lessened tensile strength. INTRODUCTION The purpose of this study was to determine the effect of hafnium additions on the properties of vanadium and to learn if this binary alloy had any special or unusual properties. This investigation is a part of a larger research project in which new and expanded uses of vanadium are being sought. Domes tic vanadium is found frequently in combination with uranium, and because of the demand for uranium as a nuclear fuel, there now exists a surplus of vanadium-bearing minerals and vanadium pentoxide as a byproduct of uranium production. Primary principles of conservation demand that greater use be made of this readily available surplus; finding suitable metals to alloy with vanadium to enhance its properties is one way to increase its utilization. This report is the result of an investigation of the effects on the properties of vanadium when hafnium is added in amounts from 1 to 50 a/o.

Jan 1, 1962

By E. H. Denny

This paper discusses accident experience and costs in 150 Colorado coal mines for the 5 years 1929-33; these mines produced 62 percent of Colorado's coal tonnage during this period. This and similar studies by the United states Bureau of Mines in other States (listed in the appendix to this report) make available comparable information on mine-accident costs and bring out clearly the importance of accident reduction from the humanitarian as well as from the economic standpoint. Compensation insurance costs constitute a considerable part of the cost of coal output. The tendency toward greater liberalization of workmen's compensation laws and increased benefits thereunder may mitigate to some extent the seriousness of an accident to a worker and his dependents, but no compensation is paid ultimately, not by an insurance fund but by the mine operator and the general public, which includes the miner. The one really effective method of reducing compensation costs is to reduce the number and severity of accidents.

Jan 1, 1935