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By M. E. Tyrrell, J. Koster

This work was undertaken to determine the feasibility of making mixed diborides of two metals directly from the metal oxides , boron carbide and carbon . The diborides (Ti , V ) , B₂ , (Ti , Cb) B₂ , and ( Ti , Ta ) B₂ were prepared in a crucible resistance furnace at 2,100 ° C , and X- ray- diffraction analyses showed each was a homogeneous solid solution containing approximately equal molar contents of the given diborides . The diboride powders were cold - pressed ; sintered to 2,300 ° C , and evaluated for mechanical strength , rate of oxidation , and resistance to molten metals . The diboride ( Ti , Ta ) B₂ exhibited the best mechanical properties ; the diboride ( Ti , Cb ) B₂ , the lowest cumulative rate of oxidation . The mixtures were stable in the presence of molten aluminum and copper but were attacked by molten Ti , Zr , and Cr .

Jan 1, 1964

By Alexander May

The U.S. Bureau of Mines conducted studies to determine if phosphate slag stockpiles at Tennessee Valley Authority's National Fertilizer Development Center were hazardous materials. The stockpiles were not hazardous materials as determined by Environmental Protection Agency (EPA) extraction procedure (EP) toxicity test. Radium-226 concentration was 28.7 pCi/g in slag and 2.1 pCi/g in background material. Radium-226 was not leached from the slag. Fluoride concentration was 3.87 pct in slag, 0.18 pct in subsurface material under slag, and 0.08 pct in the background. Slag material permeability was 1.65 x 10-3 cm/s, and subsurface material permeability was 3.24 x 10-6 cm/s. Rain water, trapped in a depression on top of the east slag stockpile, became seepage water at the base of the stockpile. Concentrations of EPA toxic elements in seepage water were much less than concentrations from an EPA EP toxicity test on the slag. Twelve elements-Na, Mg, Ca, Sr, Ba, Cr, Mn, Co, Cu, Cd, AI, and P-had higher concentrations in seepage water than in rain water on top of the slag stockpiles, or in creek water adjacent to stockpile bases, indicating that they were leached from slag stockpiles.

Jan 1, 1990

By William P. Diamond

This report presents results of a cooperative research project between the U.S. Bureau of Mines and BethEnergy Mines, Inc. Four coreholes (two before mining and two after mining) were drilled at a longwall mine operating in the Lower Kittanning Coalbed to obtain coal and rock samples from over-lying strata to determine their gas content at various times in the mining cycle. The results of those tests indicate that 91 pct of the gas removed from the overlying strata came from coalbeds. Material balance calculations were made to compare the volume of gas produced both from gob gas vent holes drilled on the panel and gas removed by the mine's ventilation system with the volume of gas removed from strata directly overlying the panel to a height of 275 ft. This analysis indicates that only 40 pct of the total gas produced from the panel actually came from the strata directly overlying the panel. The remaining volume of gas production probably migrated to the longwall gob from overlying, and perhaps underlying, strata immediately adjacent to the panel and perhaps from greater distances downdip because of the establishment of a long-term pressure gradient in the study area.

Jan 1, 2010

By B. W. Gandrud

[The Bureau of Mines is conducting an extensive investigation of coal preparation in the Alabama coal fields in cooperation with the University of Alabama and coal-mine operators. In this investigation the drainage characteristics of typical coals from the Warrior and Cahaba n fields were studied. Tire main purposes of this study has been to evaluate no nearly as possible relative influences of certain factors on rate of drainage and to determine whether the drainage characteristics of coals from different beds or from different mines on the soma bed differ materially. A further objective was the development of a laboratory drainage test that would predict approximately the rate at which any coal will drain after having been loaded into a railroad car in a saturated condition. The study has been confined to samples of slack coals - that is, coals from which none of the fine sizes have been removed. The samples ranged in upper size limits from 7/16 inch to 3 inches. It did not seem necessary to study nut and egg sizes, that is, sizes from which the fine coal has been removed by screening, as these lose water so rapidly by natural drainage that they present no serious problem in dewatering after treatment in a washer. The significance of drainage characteristics of Alabama coals is apparent in view of the fact that not less than 70 percent of Alabama?s total coal product is subjected to wet washing before being materials.]

Jan 1, 1941

By J. A. Herdlick

At the request of the War Production Board a preliminary examination of the Big Ben molybdenum prospect near Neihart, Cascade County, Mont., was made by the Bureau of Mines under G. N. Bennett, mining engineer, Bureau of Mines Montana district office, in September 1942. Formal investigation, consisting of sampling, core drilling, and metallurgical testing, was later undertaken and completed in 1943. Field work was directed by Robert D. O'Brien, mining engineer, Montana district office, under the supervision of E. W. Newman, supervising engineer, Montana district office. This report describes the deposit, presents the factual data obtained from the sampling and core-drilling operations, and summarizes the results of the metallurgical studies. The deposit was first located and prospected in 1922 by the present owner, Frank Mansikka of Neihart, Mont. Periodic examinations made by responsible mining interests were culminated in 1938 when the Federal Mining & Smelting Co. optioned and investigated the property. No ores have been produced from the deposit to date.

Jan 1, 1949

By James J. Dowd

The investigation to evaluate the reserves of coking coal is being made by the Bureau of Mines in three parts: (1) To estimate known measured and indicated recoverable reserves of all coking coal; (2) to upgrade marginal coals through effective preparation; and (3) to study the carbonizing properties of coal and coal blends not now widely used for metallurgical coke making. This is the tenth of a series of reports giving the results of studies by counties under part (1) of the investigation. (See appendix.) This report covers Knott County, Ky., which comprises parts of the Salyersville, Prestonsburg, Troublesome, Hindman, Pikeville, Cornettsville, and Whitesburg quadrangles. (See fig. 1.) A base map for each bed in each quadrangle was made to the scale 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all available data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds up to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick. These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and category, mined-out areas, areas excluded from the estimate but which may contain reserves based only on geologic inference, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1952

By Thomas P. Mucho

Retreat or pillar recovery mining redistributes the overburden weight onto the adjacent coal pillars in a room-and-pillar section. The additional stress and the resultant energy stored in the remaining pillars can become so great that pillars may bump or violently fail. An investigation at the Gary No.2 Mine was conducted to examine the effectiveness of the thin pillar mining method for mitigating bump occurrences. Field observations were made and instruments were installed to monitor pillar behavior during extraction. Stress monitoring instruments and roof-to-floor convergence stations were installed in pillars and entries and crosscuts, respectively. Results indicated that high pillar stress concentrations occurred in these bump-prone geologic conditions. The thin pillar mechanism, the creation and progressive outby movement of an expanded yield zone, was also monitored through the instruments. The expanded yield zone, a result of using thin pillars in a highly stressed pillar line area, mitigates bump risk.

Jan 1, 2010

By Robert F. Chaiken

The U.S. Bureau of Mines conducted an experimental and theoretical study of coupled chemical kinetic and mass transport processes during leaching of pyrite from coal in a counterflow, "trickle-bed" column reactor. Spatial and temporal data on reactant and product concentrations were used as solutions to appropriate continuity equations, which in turn define chemical kinetic reaction rates. Data from four 180-by 30-cm column leaching experiments using coal, coal waste, and air-water and air-FeC13 lixiviants have been analyzed. The rate of leaching was found to be diffusion limited (probably by Fe3+) and not controlled by bacterial action. Rates of pyrite oxidation were found to vary with elapsed time (80 to 225 days) and followed a bell-shaped curve, sometimes with a delay before start of reaction. Maximum rates of reaction ranged from 3 to 10 (mmol/d)/L (column) for coal waste and 0.4 (mmol/d)/L (column) for coal. Reaction was 30 to SO pct complete, probably due to precipitation of product salts (e.g., jarosites), which impede transport of oxidant through the coal. An absorption-desorption model of solids leaching, which considers the role of heterogeneous porosity in solids leaching, was used to describe time-dependent leaching rates.

Jan 1, 2010

By R. E. Kennedy

The presence in air of combustible cases and vapors can constitute an extremely serious explosion hazard. This hazard is even greater when explosive mixtures are confined under high pressures, as the pressure can become tremendous immediately before the container is ruptured. Because of its interest in safety in mining and allied industries, the Federal Bureau of Mines has investigated the flammability (explosibility) of various types of combustible atmospheres and has published Its findings. 4/ The explosibility of ethane has been studied, and its limits of flammability have been determined and published. The development of secondary recovery methods of stimulating oil production has intensified interest in the effect of high pressure on the explosibility of natural gas-air mixtures. The limits of flammability of natural gas-air mixtures at pressures ranging from 50 mm. Hg to 350 p.s.i.a. have been determined and published. More recently, the limits have been determined at pressures up to 3,00C p.s.i. in mixtures of natural gas-air-nitrogen.

Jan 1, 1950

By Lloyd Williams

1. The investigation shows that the Pewee, Big Mary, and Windrock are the most important beds in Anderson County. About 73 percent of the known recoverable reserves of coal in the county are in these beds, and from them comes 94 percent of the production. The remaining reserves tabulated in this report are in the Joyner, Jellico, Coal Creek, and Poplar Creek beds, and 6 percent of the county production comes from these beds. No production is being reported at present from the Jellico bed, although it was mined years ago. 2. Known measured and indicated reserves in all beds, bared on a minimum thickness of 1/4 inches and on 1,800 short tons put acre-foot of coal in place, are estimated to be 170 million torts as of January 1, 1953 Of this total, 155 million tons is in beds 2S inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to permit making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to they total estimated reserves.

Jan 1, 1955

By D. W. Mitchell

This Bureau of Mines report summarizes experience and past research on methods for sealing abandoned areas of a coal mine and areas from which the pillars have been wholly or partially extracted. The Federal Coal Mine Health and Safety Act of 1969 requires that such areas be ventilated or sealed with explosion-proof bulkheads, but the present study indicates that bulkheads alone cannot isolate areas in a coal mine in which methane and other dangerous gases have accumulated. Gas-air exchanges between sealed and open areas must be controlled.

Jan 1, 1971

By John Gross

Studies in grinding efficiencies carried out at the Midvale plant of the U. S. Smelting, Refining & Mining Co. and at the Tooele plant of the International Smelting Co. Were made possible by the cooperation of these two companies with the U. S. Bureau of Mines. Mr. Alan Probert of the U. S. Smelting, Refining & Mining Co. and Mr. E. C. Peterson of the International Smelting Co., devoted their entire time to the work during the respective tests, and their services are hereby gratefully acknowledged. It is a pleasure to acknowledge also the assistance and kindness of the staffs of both companies in making it possible, at considerable trouble and expense, to sample the entire mill circuits and in furnishing the necessary supplies and special apparatus required in the work.

Jan 1, 1929

By R. A. Beall

This paper summarizes the development of a furnace for producing titanium castings. The general problem is outlined and chronological details are given on the construction and operation of four different casting furnaces, all utilizing consumable-electrode arc heating and water-cooled copper crucibles. Of the two methods of pouring, the tilt-pour technique has been more satisfactory than bottom tapping. Mold design, electrode fabrication, and deep-pool production are discussed. INTRODUCTION In the early summer of 1953 the Bureau of Mines was contacted by the Department of the Army through Watertown Arsenal to explore the possibility of conducting research on casting titanium metal. The objective of the program was "to develop a technique for producing formed castings of titanium metal not less than 40 pounds in weight and without introduction of deleterious contamination."

Jan 1, 1956

By Joseph M. Singer

Having established that sodium chloride reduces the incendivity of explosives, the Bureau of Mines studied the effect of sodium nitrate in reducing ignition hazards. Gallery experiments showed that sodium nitrate reduced the incendivity of certain explosives to 8 percent natural gas in air but increased their incendivity to coal dust predispersed in air. Laboratory experiments using hot jets from explosions of stoichiometric mixtures of methane-oxygen-nitrogen showed that both sodium chloride and sodium nitrate reduced the incendivity to methane, to mixtures of coal dust and methane) and to coal dust. The difference between the gallery and laboratory results with respect to coal dust is attributed to temperature-time effects.

Jan 1, 1967

By R. L. Hopkins

Fifteen alkyl cycloalkyl sulfides and three dicycloalkyl sulfides were synthesized to provide reference compounds in the search for these classes of sulfur compounds in crude oils. In synthesizing sulfides by alkaline alkylation the order in which the reactants were added was shown to determine the yield and purity of the product.

Jan 1, 1966

By Martin A. Elliott

The Bureau of Mines began its investigation of the use of Diesel engines underground to provide technical information necessary to assist this development in the United States. It was considered desirable to furnish such assistance because successful European developments/ in this. field had indicated that Diesel mine locomotives might be safer than electric trolley locomotives. The Bureau has recognized for some time the importance of eliminating the hazards associated with underground haulage systems using bare trolley wires. For example, each year 30 to 40 fatalities occur as a result of electrocution by contact with bare trolley wires. In 1943 and 1944, 101 men were killed and extensive property damage occurred as a result of mine fires started by falls of roof grounding the bare trolley wires.

Jan 1, 1948

By Clayton M. Rumsey

The U.S. Bureau of Mines investigated prospects and mineralized areas in and adjacent to the Indian Pass and Picacho Peak study areas in 1983 and 1984. The Indian Pass study area contains 33,640 acres and the Picacho Peak study area contains 5,450 acres. The study areas are located in the southeast corner of California and are underlain by Precambrian gneiss, Pre-Tertiary metavolcanic and metasedimentary rocks, and Tertiary volcanic and non-marine clastic rocks. Low-grade gold-silver resources may be present in hydrothermally altered gneiss in the upper plate and altered schist in the lower plate of the Chocolate Mountain thrust fault. The thrust fault is exposed in the study areas for about 3.5 miles west and 5 miles east of Indian Pass. Mineralized zones in the thrust plates were not discovered until 1983. Earlier prospecting explored areas containing minor copper carbonate occurrences in schist and sedimentary and volcanic rocks that are younger than the thrust. Twenty-three mines, prospects, and mineral occurrences inside the study areas and fourteen outs; de were examined for this study. These surficial copper occurrences have been prospected extensively in the study areas; large areas have been scraped, pitted, and trenched by bulldozers. However, they appear to be of limited economic significance. Slightly mineralized zones are in the northwest part of the Indian Pass study area where granite contacts sedimentary and volcanic rocks.

Jan 1, 1986

By J. M. Stuve

Low-temperature heat capacities and the enthalpy of formation were deter-mined calorimetrically by the Bureau of Mines for CuO?CuS04. The derived standard entropy (S°298.15) was 40.36±0.04 cal/deg-mole, and the enthalpy of formation (?H°f) was -219.l±0.3 kcal/g-mole. A large thermal anomaly was observed in the heat capacity of CuO?CuS04 at 20±0.1 K. Gibbs energy of formation data are tabulated up to 1,200 K. Construction details of a precision low-temperature adiabatic calorimeter capable of determining heat capacities of solids in the temperature range 5 to 320 K are given. A calibrated miniature germanium resistance thermometer was incorporated into the calorimeter to extend the range of accurate measurements below 15 K. High-resistance dc heater windings were used throughout the cryostat to reduce heat conduction of inner connecting wires.

Jan 1, 1975

By John Nagy

The effect of low percentages of methane (0 to 5 pet.) in an air atmosphere on spark initiated explosions of coal dust was investigated. With low dust concentrations (0.1 to 0.4 oz./cu, ft.), small amounts of methane increase the explosion pressure; with larger dust concentrations (0.5 to 2.0 oz./cu. ft.), small amounts of methane decrease the explosion pressure. The rate of pressure rise of a coal dust explosion increases with increase in methane concentration; about 3 to 4 pct. further addition of methane yields a decrease in the rate of pressure rise. Convection currents created by the air or gas blast used to disperse dust produce an increase in explosion pressure and rate of pressure rise. The minimum explosive concentration of the coal dust decreases about linearly as the concentration of methane increases from 0 to 5 pct. The explosion pressure increases linearly as the initial pressure within the chamber increases. Similarities between coal dust and methane explosions are indicated, INTRODUCTION During coal mining, methane occluded in coal or adjoining strata is liberated into the mine atmosphere,4 Normally, the methane is diluted and swept away by the ventilating air. Under some conditions, through accidental disruption of the ventilation system, sudden outburst, or because insufficient fresh air is supplied to a working place, low percentages of methane may be present during mining operations. If it is permitted to accumulate, methane itself presents an explosion hazard; its limits of explosibility arc approximately 5 and 15 pct. The effect of low percentages of methane on the explosibility of coal dust was studied to provide a broader understanding of the hazards of ignition and explosion and thus to facilitate development of control

Jan 1, 1961

By J. H. Tylczak

The Bureau of Mines studied the effect of alloy additions on abrasive wear of low-alloy steels. A dry-sand, rubber-wheel abrasion test appa-ratus using ASTM G65-Sl procedure B was used for the abrasive wear tests. Eighty-six material heat-treatment combinations were abrasion tested. Results of these tests were analyzed statistically using regression analysis to see if additions of Cr, Mn, Mo, Ni, Si, AI, Cu, and S were significant in affecting the abrasive wear rate of low-alloy steels. Regression analysis was also used to confirm hardness and C affect on the abrasive wear rate of these steels. It was found that for all the steels taken as a group, increased amounts of Mn significantly reduced the wear rate, while increased amounts of Mo and S1 increased the wear rate. Analysis also confirmed previous research done by others, that increasing hardness and amounts of C reduced the wear rate. For the hardened steels taken as a class, only increasing amounts of C and Mn reduced the wear rate, while increases in Si increased the wear rate. In the class of unhardened steels, increases in C, Mn, and S re-duced the wear rate, whereas increases in Mo increased the wear rate. The steels with the best resistance to wear were two hardened experimen-tal steels similar to AISI 1055 and AISI 107S.

Jan 1, 1986