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By Russell R. Trengove

Bureau of Mines exploration at the property of the Tulare County Tungsten Mines was by core drilling from the surface from May 16, 1950, to July 13, 1950. The property is in the western foothills of the Sierra Nevada Range, 18 miles northeast of Lindsay, Calif. It has been in almost continuous production since 1942 and has produced 40,831 units of tungsten trioxide (W03) with a grade of approximately 67 percent. The work performed comprised a study of the geology, mapping the area, sampling the outcrops, and diamond drilling the area adjacent to the mine workings. Ten holes were drilled for a total of 1,824 feet. Ore reserves were found to be confined to tactite zones in a surface area approximately 250 by 400 feet and extending downward about 350 feet.

Jan 1, 1956

By S. H. Brooks

"IntroductionThis preliminary report deals with the effect of oxygen pressure on the ignition temperature and combustibility of oils, it is the third of a series which will present the results of an investigation being made by the Bureau of Mines, on oxygen-oil explosions. The purpose of this research is to obtain technical data that will serve as a basis for safety precautions general outline of the problem has been given in the first report (Serial 2507).The present experiments have resulted in (1) a method for determining spontaneous ignition points of oils in an atmospheric of oxygen under pressure; and (2) the determination of these ignition temperatures for three typical oils, one being an animal oil (sperm), one a vegetable oil (linseed), and one a mineral oil (""Moiloil A"").These experiments on explosibility of oil were performed in order to discover the general nature of the phenomenon, especially the order of magnitude of the temperature necessary for spontaneous explosion (120°C. and upwards) and the effect of pressure variation (negligible as regards ignition temperature but important in relation to the violence of the explosion). A continuation oftests should provide a basis for selecting the safest lubricants for high pressure compression of gases particularly air and oxygen; and should be of value when devising new specifications for lubricants, both in the government departments and the compressed-gas manufacturing industry."

Dec 1, 1923

By T. W. Johnson

One of the common methods of increasing recovery of oil from partly depleted oil sands is to inject natural gas, air, or air-gas mixtures into the sand, thereby supplying energy to move oil into the well bore. Where natural gas is not available, air or an air-gas mixture is used as the repressuring medium. Air-gas mixtures are obtained from the casing-heads of oil-producing wells in the areas repressured with air or air-gas mixtures and consist usually of varying amounts of the hydrocarbon gases, nitrogen, oxygen, and carbon dioxide. Laboratory experiments have been conducted by the Bureau of Mines to determine the effect of air on crude oils.4/ In these experiments the crude oils were oxidized by the air, and the degree of oxidation depended not only upon the chemical composition of the crude oil but also upon the duration and method of contact between the oil and air, the temperature of the fluids and the concentration of the oxygen. When the crude oils were oxidized the following results and changes in the oils were obtained:

Jan 1, 1937

By T. W. Johnson

One of the common methods of increasing recovery of oil from partly depleted oil sands is to inject natural gas, air, or air-gas mixtures into the sand, thereby supplying energy to move oil. into the well bore. Where natural gas is not available, air or an air-gas mixture is used as the repressuring medium. Air-gas mixtures are obtained from the casingheads of oil-producing wells in the areas repressured with air or air-gas mixtures and consist usually of varying amounts of the hydrocarbon gases, nitrogen, oxygen, and carbon dioxide. Laboratory experiments have been conducted by the Bureau of Mines to determine the effect of air on crude oils.4/ In these experiments the crude oils were oxidized by the air, and the degree of oxidation depended not only upon the chemical composition of the crude oil but also upon the duration and method of contact between the oil and air, the temperature of the fluids and the concentration of the oxygen. When the crude oils were oxidized the following results and changes in the oils were obtained:

Jan 1, 1937

By John W. Cole

As part of a general preliminary investigation of lead-zinc deposits in Stevens County, Wash., the Electric Point and Gladstone mines on Gladstone Mountain, in the Northport Mining District, were examined by R. M. Gammell, an engineer of the Bureau of Mines, in June 1946. A trenching and sampling program was executed later the same year under' the supervision of Miro Mihelich and the author. This report presents the factual data obtained from the trenching and sampling operations.

Jan 1, 1949

By Edward L. Burwell

The Bureau of Mines conducted laboratory experiments to determine the change during retorting in the apparent permeability and the degree of compaction of beds of broken oil shale. Grades of oil shale studied ranged from 20.6 to 46.7 gallons of oil per ton (gpt), and the simulated overburden pressures applied to the shale were from 300 to 900 psi. Linear regression analysis of the data produced equations describing the response of the oil shale. Oil shales of approximately 20 gpt experience only minor apparent permeability reductions under test conditions, but richer shales (30 to 50 gpt) lose essentially all permeability. The permeability reductions were accompanied by corresponding decreases in bed height that ranged up to 37 percent of the original bed height.

Jan 1, 1974

By P. N. Summerfield

This report describes the first phase of a general investigation designed to ascertain whether an electronic roof-testing device can be developed that will improve the ability to detect "loose" or "drummy" roof rock over that possible by striking the roof with a sounding bar and noting the character of the air vibrations with the unaided ear or the rock vibrations with the fingers. The amplitude, frequency content, and duration of the vibrations produced by striking solid and drummy roof rock with a hammer or sounding bar have been measured. Results disclosed that there is a significant difference between the characteristics of the vibrations produced in solid and drummy roof. This difference is such that the design of an electronic device to indicate quantitatively the condition of the roof rock appears possible. INTRODUCTION The conventional method of roof testing consists of striking the roof with a bar2/ and judging its soundness from the character of the air vibrations heard with the ear and/or the rock vibrations felt with the fingers -a procedure that depends upon the experience and the sensory abilities of the observer. Impact testing of a solid roof rock usually produces a sharp ping or click, whereas impact testing of a drummy roof rock produces a dull thud or drummy sound. This method of roof testing is, at most, only a qualitative test, and many roof rocks are difficult to classify as drummy or solid.

Jan 1, 1956

By Clyde M. Pearce

The Lake Superior iron-mining district includes parts of the States of Michigan, Minnesota, and Wisconsin. The laws of each State provide for an industrial commission and for inspection of mines. The following extract from the General Orders on Mines, effective October 25, 1937, issued by the Industrial Commission of Wisconsin, is the only reference to the use of safety catches on mine cages or skips found in the laws and regulations in the Lake Superior iron-mining district: Order 316 - Cages for Hoisting Men. (c) Sides, Gates, and Safety Catches. ***Every cage shall be provided with safety catches of sufficient strength to hold the cage with its maximum load at any point in the event the hoisting cable should break. (d) Testing Safety Catches. The safety catches of cages and skips used to hoist men shall be kept well oiled and in good working order. They shall be tested at least once each month by tying up the cage or skip with hemp rope, lowering a few feet of hoisting cable on top of cage, then cutting the hemp rope, provided that any other system of testing, which is equally effective, may be used.

Jan 1, 1945

By R. Hogg, T. H. Dumm

"The mathematical treatments used in the evaluation of particle size distribution from pipet-withdrawal centrifuge data are reviewed. An error in the published procedure for multiple-sample withdrawal systems is pointed out and a corrected formulation is presented. An alternative treatment, based on a piece-wise linearization of the size distribution is described. Computer simulations of the analytical and data evaluation procedures indicate that the errors in the original formulation are not generally serious and that the corrected and alternative procedures lead to very similar estimates. Except for some cases involving very narrow size distributions, the alternative approach appears to give slightly closer estimates of the size distribution. Comparisons based on actual experimental data are also described.1 IntroductionSedimentation methods are widely used for the determination of particle size distributions. The procedures are relatively simple to use and the results are essentially absolute, requiring no external calibration. Gravity sedimentation is typically applicable to particles in the size range of about I to 50 pm and generally involves measurement of the relative concentration of particles as a function of depth and time in a dilute suspension. Particle size is calculated using Stokes, law:"

Mar 1, 1989

By R. C. Bates

Uranium mine workers? daily exposure to radon daughters was estimated by two methods of sampling, detailed and spot-check. Both methods involve time- weighting measured exposure levels to arrive at an average exposure figure. Random sampling, or sampling without regard for the duration of exposure, has proved inadequate for estimating average exposure levels. During the first phase of the study, the breathing zones of eight workmen in three underground uranium mines were sampled for an entire shift; 20 to 36 radon-daughter samples were collected per man-shift, Analysis of these data indicated that a suitably accurate estimate of the full-shift exposure could be made by time weighting a considerable lesser number of representative radon-daughter samples. This analysis led to the spot-check method of estimating full-shift exposures to radon daughters. Additional detailed studies were made in seven mines to Learn more about the full-shift radon-daughter exposures and to test the spot-check method, In all, 617 radon-daughter samples were taken in 10 underground uranium mines during 26 man-shifts, and the spot-check method was tested 35 times.

Jan 1, 1962

By Walter Wood, J. T. H. Cannarella, H. F. Yancey, R. E. Zane

More than 50,000,000 tons of bituminous coal and probably about the same quantity of anthracite are cleaned annually in the United States by wet methods. The water, fine coal, and impurities from the water used for washing ordinarily are recovered by moans of various forms of settling tanks. Settling and clarification may be hastened markedly, thereby greatly increasing the capacity of clarification equipment already installed, by the addition of substances to the washery water that cause the fine particles in suspension to agglomerate and thus settle more rapidly. This phenomenon, although well known and applied in other fields, has been used at only a few coal washeries in the United States. It is widely employed, however, as an aid in the recovery or disposal of fine coal or impurities, as a means of preventing, stream pollution, and to enable reuse of washery water at many plants in Europe. Pioneering work in the United States has been done principally by two companies -- the Pittsburgh Coal Co., in Pennsylvania, 6/ and the Pacific Coast Coal Co., in Washington.

Feb 1, 1940

Comparative tests of four coals used industrially for coke production have been made by three laboratories of the Federal Bureau of Mines, each using its standard equipment and procedures for evaluating coal for coking. Two of the coals were blends used in the western and eastern sections of the United States, the third was a strongly coking coal widely used for producing coke in Alabama, and the fourth was a blend typical of those used for producing foundry coke in the Birmingham district. The coals used and the cokes produced from them covered a wide range of chemical and physical properties. The tests used at all three laboratories for determining the physical properties of the cokes were made according to ASTM (American Society for Testing Materials) methods. The excellent agreement found for the physical properties of the cokes indicated that, for the coals tested, the BM-AGA (Bureau of Mines-American Gas Association) 18-inch circular retort used at Pittsburgh, Pa" the 14-inch slot-type oven used at Denver, Colo., and the 17-inch slot-type oven used at Tuscaloosa, Ala., were substantially equivalent for evaluating coals for production of coke. Thus, added value is given to data obtained previously and independently at these three Bureau laboratories. INTRODUCTION Laboratory equipment to produce coke for evaluation has not been standardized by the industry. The results obtained with anyone design of equipment have been regarded as showing only the relative values of coal to produce coke of the requisite quality. Few systematic studies have been made to correlate results obtained in different types of equipment. Results of one, in which the Bureau of Mines participated, were published recently.2/ This

Jan 1, 1961

By L. A. Stewart

"SUMMARYThis paper describes most of the chrysotile-asbestos deposits of Arizona. Mining methods are discussed briefly and asbestos-mill flowsheets are incorporated. Arizona asbestos mines are the only sources on the American continents of naturally iron-free chrysotile spinning fiber that is so urgently needed for electric-cable coverings, especially on warships.Asbestos was first recorded and recognized in Arizona in 1872, and a minor amount was produced from a deposit in the Grand Canyon in 1900. The discovery of a deposit in the Salt River district in 1912 initiated intensive prospecting, and deposits soon were developed. The total Arizona production of all grades of asbestos through 1953 is estimated at 30,000 to 35,000 tons.The deposits of the Central Arizona region, which are discussed in this paper, are scattered over nearly 2,000 square miles. The annual output is relatively small, because the asbestos occurs in thin, discontinuous veins and only in areas where intrusions of diabase are adjacent to or crosscut certain favorable units of the pre-Cambrian Mescal limestone. This stratigraphic limitation, combined with other essential geologic conditions, tends to restrict the size of the deposits.Virtually all of the deposits are in rugged, mountainous country, and many of the mines are on steep canyon walls. In the average mine, production of 1 ton of commercial asbestos requires removal of 30 to 40 tons of waste rock. Mining and transportation costs consequently are high.Several deposits of chrysotile that is somewhat harsh and of moderate tensile strength have been known for years but were not worked because of the former exacting demands of industry for high-strength, soft asbestos. However, improve¬ments in asbestos fiberization and spinning technique, combined with the urgent need for asbestos, have made this so-called semisoft fiber desirable, and deposits of this type now are being exploited."

Jan 1, 1955

By F. J. Palumbo

An electronic color-sorting machine was tested for recovering colorless glass concentrates from mixed glass products. The tests were made using glass recovered from unincinerated (raw) urban refuse and residues resulting from the incineration of refuse. The results of the study revealed that concentrates analyzing about 86 percent colorless glass could be recovered from mixed unincinerated glass containing 54 percent colorless glass material. Recovery of the colorless glass was about 62 percent. Color sorting the incinerated glass was somewhat more difficult. Multiple-stage processing was required to recover 59 percent of the colorless glass material in a product analyzing 89 percent colorless glass. The feed material analyzed 41 percent colorless glass.

Jan 1, 1971

By Walter Kawa

Coals of various rank were reacted by the Bureau of Nines in plasma jets generated from argon and argon-hydrogen mixtures containing up to 33 volume-percent hydrogen. Average plasma temperatures ranged from about 3,400° to 12,000° C. Products were a solid residue and a gas containing hydrogen, methane, acetylene, diacetylene, and oxides of carbon. The highest yield of acetylene obtained with argon plasmas was 15 percent by weight of moisture- and ash-free coal. The data indicated that acetylene yields of 40 percent or higher can be obtained from the reaction of coal in argon-hydrogen plasmas, although results from these experiments could not be correlated with operating variables because of low recoveries plasma contained sufficient energy to heat the coal to temperatures as high 9,000 or 10,000° C, but complete devolatilization did not occur in any experiment.

Jan 1, 1966

By Albert W. Deurbrouck

This report describes the preparation characteristics of 23 coal samples collected from nine of the more significant coalbeds of Fayette County, W. Va. In 1963 almost 5.4 million tons of medium to high volatile B coals of excellent quality for metallurgical and steam markets were produced in Fayette County. Of the 23 coal samples collected 11 would require some upgrading to pro-vide metallurgical quality products, 11 were acceptable as received, and 1 was a noncaking coal. Cleaning these coals to metallurgical standards would require only the removal of the sink 1.58 specific gravity material which would be quite easy as very little near-separating-gravity material was present at this gravity.

Jan 1, 1965

By Frank E. Williams

Nuclear detonation data were accumulated, studied, and evaluated by the Bureau of Mines to visualize how nuclear explosives might be used in a shale?-oil industry, The evaluation shows that the Green River Formation at the semi-isolated locale of Piceance Creek Basin, in northwestern Colorado; is thick and widespread enough to warrant consideration of nuclear mining in lieu of conventional methods, Because cost data for nuclear explosions are limited; cost comparisons are made largely by assumptions. Also described are the history of the shale-oil industry, the geology and size of oil-shale resources; and conventional mining methods and processing technology.

Jan 1, 1969

By Arne Landsberg

A study of the chlorination kinetics of germanium, silicon, iron, tungsten, molybdenum, columbium, and tantalum has been made to determine the effects of temperature, chlorine concentration, geometric surface area and gamma radiation. The reaction products were volatile at the temperatures used this making it possible to follow the reaction rates by weight loss of the solid. Chlorination rates of germanium, silicon, and iron were found to be directly proportional to chlorine concentration while the rates for tungsten, molybdenum, columbium, and tantalum were proportional to the 0.5 to 0.6 power of chlorine concentration. A good correlation of reaction rate and geometric surface areas was not obtained because the true surface area of the samples could not be measured. Intense gamma radiation had no effect on reaction rates. The Arrhenius activation energies determined over the temperatures used are as follows: Germanium, 27 kcal/mole (233°-241° C); silicon 33 kcaL/mole (375°-517° C); iron, cold rolled, 20 kcal/mGle (259°-325° C) annealed, 21 kcal/mole (293°-337° C); tungsten, 43 kcal/mole (617-776° C); molybdenum, 37 kcal/mole (445°-4910 C); columbium) 34 kcal/mole (229°?255° C); and tantalum, 29 kcal/mole (370°-449° C).

Jan 1, 1965

To provide longwall operators with a method to predict methane emissions from panels with increased face width.

Jan 1, 1997

By B. W. Naugle

Twenty-nine sole-heated-oven expansion teats were made on 9 different coals, and apparent specific-Brevity tests were made on 12 of the resultant cokes. The coals, which ranged in dry, mineral-matter-free fixed-carbon content from 58.7 to 81.1 percent, were tested over a rather wide range of moisture content and dry-coal bulk density to determine the separate effects of these variables on linear coal expansion. The experimental data support the follow expression relating "as-tested" coal bulk density, moisture content, and linear expansion, [ER = (1-MR) (1+Et) - 1; BDt] where ER = fractional expansion at a reference bulk density of 55.0 lb. of 1 percent moisture coal per cu. ft., Et = fractional expansion at Mt and BDt, MR = reference moisture content = 0.01, Mt = moisture content, "as-tested", BDR = reference bulk density = 55.0 lb. per cu, ft., BDt = bulk density, "as-tested", 1b. per cu. ft.

Jan 1, 1957