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By E. E. Maust

The present work is part of an ongoing Bureau of Mines effort to provide a better understanding of the fundamental phenomena involved in sulfide flotation, the role of oxygen in xanthate adsorption being one essential issue. Galena was chosen as the material around which to develop a conceptual model, partly because of its demonstrated oxygen sensitivity and partly because information on its properties and flotation behavior constitutes the largest part of the fundamental information available on sulfides of commercial importance. The model is formulated primarily in terms of surface electronic energy levels produced by oxygen and xanthate and is further developed using existing experimental evidence and its implications. Four major functions of oxygen are elucidated, and the relationship of these to the formation of lead xanthate, dixanthogen, and a surface compound is discussed. Though yet incomplete, the model provides a useful framework within which the results of diverse experiments can be related to one another in their proper perspective, as shown by a brief discussion and resolution of some apparently discordant results reported in the literature.

Jan 1, 1976

By Robert H. Ridgway

This circular outlines salient facts regarding the sulphur industry of the United States and the world. It is founded chiefly upon published information available in the literature of the subject. The Bureau of Mines has in its files additional, more detailed data upon many of the topics presented very briefly here, and will endeavor to assist the mineral industries and the public by giving further information in response to individual inquiries. It will welcome comments, criticisms, and contributions of data that may assist in making later editions of this circular more accurate, or in developing more fully the bureau's mineral files pertaining to sulphur. Throughout this paper sulphur is used to designate crude sulphur or brimstone, not sulphur produced from pyrites or' smelter gases.

Jan 1, 1930

By Manuel Gomez

The Bureau of Mines used data from 31 core samples to develop prediction equations for evaluating chemical and carbonization properties of six seam units in a lignite deposit approximately 2 miles wide and 8 miles long in the Wilcox Formation of central Texas. Statistical response surfaces, based on core analyses, were computed for 14 parameters indicative of lignite quality. These computed surfaces, and their mathematical equations, can be used to predict values of the selected properties of the lignite seams at any desired surface coordinate position between core hole locations. The wide range of application shown by this study indicates that the methods of statistical regression analysis may be useful to evaluate large deposits of lignite or higher rank coal.

Jan 1, 1969

MR. RIGG: Gentlemen, I would like to welcome you all to the symposium this morning. My name is Jack Rigg, and I m a special assistant to Hollis Dole, Assistant Secretary of the Interior for Mineral Resources. Hollis is not in town this morning, and I am here to pinch-hit for him. The first order of business this morning is remarks by the Honorable Russell Train, Under Secretary of the Department of Interior. Mr. Train. MR. TRAIN: Thank you, Mr. Rigg. Lest you think that Hollis Dole is not interested in this symposium, let me just say that fie is flying back from Australia just to be here. He is heading up a United States delegation in Australia meeting on resource problems in the Pacific. And I believe he will be here about noon.

Jan 1, 1970

By Tobias W. Goodman, George N. Aul, Joseph Cervik

The Bureau of Mines conducted research to degasify a virgin block of coal in the Beckley Coalbed using long horizontal holes drilled in an array from the bottom of a ventilation air shaft. Eight horizontal holes and an in situ pressure hole were drilled in a radial pattern to depths ranging from 418 to 910 ft (127 to 277 m) and 205 ft (62 m), respectively. The investigation showed the shaft was in a basin saturated with water, which resulted in low gas flows from holes. The in situ pressure at 200 ft (61 m) into the coalbed was 79 psig (544.6 KN/m2). The aver- age gas and water flows for the eight holes were 94,100 ft3/day (2,665 m3/day) and 13 gal/min (49.3 l/min) . After 514 days of degasification, 18.7 million ft3 (0.53 million m3) of gas had been drained. Methane face emissions, which were measured as a section advanced toward the shaft, were reduced about 77 pct, emphasizing the value of drainage by this technique. All holes were grouted before the area around the shaft was mined.

Jan 1, 1982

By D. F. Reed

As a part of a comprehensive survey of the Adirondack region, the Bureau of Mines, 1944 and 1945, conducted investigation of magnetic deposits at Dennemora, Russia Station, Redford-Clayburg, Standish, and the Ausable river region. Later in 1945, the Federal Geological Survey, started an aeromagnetic survey of the area and completed it in .1946. The Bureau of Mines extended its magnetic surveys in 1946 in the Redford-Clayburg area. In 1947 the Bureau of Mines .diamond-drilled throe holes in the Redford-Clayburg district. Clinton County has one active magnetite mine at Lyon Mountain and inactive mines at Palmer Hill and Arnold Hill, as well as along the Saranac River.

Jan 1, 1949

By Berger

A detailed description is given of radio apparatus for controlling a coincidence outfit for relative gravity measurements. This is probably of little interest, since many types of apparatus could be used. The general method employed is the interesting thing about this paper. As long ago as 1883 von Sterneck made a proposal to control two coincidence boxes with the, seine, clock, and many persons have suggested the use of radio for this purpose. In accomplishing this it would appear to the reviewer that this method is probably inferior to that used by the Marland Oil Co., but Berger and Brückner must be given the credit for important advances in the coincidence method. In their apparatus a clock at a central station actuates a relay, which operates a short-wave transmitter (40 m.). At the receiving station the amplification is accomplished at low frequencies... The signal operates a relay which moves a slitted screen in a coincidence apparatus. This screen has been improved considerably, to decrease the mean error in observing a coincidence. As usual, a telescope is used to observe the flashes of light. It has a scale in its focal plane and positions of successive flashes are easily read off and recorded by a second observer. This makes possible' a: higher accuracy in determining the exact instant at which coincidence would have occurred at the zero point on this scale. This method obviously depends on the constance of the mechanical and electrical lag inn both sending and receiving apparatus, and may be adversely criticized from this standpoint. -- A. E. Ruark.

Jan 1, 1929

By Donald P. Schlick

The Federal Coal Mine Health and Safety Act of 1969 requires each mine operator to implement the respirable dust sampling program established by the Secretary of the Interior and the Secretary of Health, Education, and Welfare. This program requires frequent sampling of "high-risk" face workers and periodic sampling of other underground workers. Dust samples are collected by the coal mine operator and weighed at the Bureau's Pittsburgh Field Health Group, and the results are processed by the Bureau's Automatic Data Processing Section located in Denver, Colo. This paper presents the system employed by the Bureau to weigh the dust samples and to process and store the data.

Jan 1, 1971

By Donald W. Mitchell, John Nagy, Edwin M. Murphy

"Investigations in the Federal Bureau of Mines Experimental coal mine near Pittsburgh, Pa., have shown that high-expansion foam containing at least 0.2 ounce of water per cubic foot of volume is effective in controlling exper-imental underground coal, oil, or wood fires. Some of the fires were extinguished, but more of the coal and wood fires were brought under enough control to permit direct attack with water or other extinguishing agent or loading the hot material into cars. The largest controlled experimental fire, which burned about 5 hours before attack, was in a coalbed 5 feet wide, 10 inches thick, and 100 feet long. The greatest distance foam was transported to control a fire was 1,010 feet.An incipient fire should be attacked promptly with water, rock dust, or other approved and readily available extinguishing agents. Where heat, roof falls, and smoke prevent direct approach, the more involved procedure of using foam may be advantageous. The effectiveness of the foam in controlling a deep coated fire of considerable extent H,vet to be proved by actual trials in aSome hydrogen, carbon monoxide, and methane gases are generated when a fire is attacked with foam. Calculations showed that in experimental fire tests an explosive mixture could form; however, this would occur only within a narrow range of combustible gas-air mixtures not likely to be found in practice. The principal explosion hazards are due to generation of gases by the foam, localized build-up of normally liberated methane, and volatiles liberated by the coal during heating. The quantity of combustible gases generated by the action of the foam on the fire is about the same as that when an equivalent amount of water is applied."

Mar 1, 1960

By J. L. Reuss

The Bureau of Mines derived information on the softening characteristics of both unfired and indurated iron ore pellets as measured by hot compression strength in a laboratory study. A surprisingly high hot strength (240 1b per ½ -inch spheroid) was developed by unfired magnetite pellets near 900° C; lesser maxima were developed by pellets made from hematite and specularite concentrates near 1,000° C. Those from goethite remained weak throughout the pre induration heating. Fully indurated commercial pellets retain a high resistance to softening when heated in air. On the contrary, in a hot reduing atmosphere their high cold crushing strength dissipates rapidly. At 1,000° C, for example, the average compression strength of seven different commercial pellets was 110 lb; at 1,100° C, the hot strength was only 60 lb. After a rather sharp initial drop, the loss of strength with increase of temperature was gradual. There was no sudden collapse, nor any significant difference, in behavior of commercial pellets whether made from magnetite or hematite concentrates.

Jan 1, 1968

By Liane L. M. Kacinuck

This U.S. Bureau of Mines publication is intended to provide mining industry representatives and regulatory authorities with a reference package dealing with studies on hydrology and underground mine subsidence. An annotated bibliography and a list of additional sources are given and represent references published prior to June 1993. Ninety-two references ware identified and 72 obtained for assessment. Annotating the references included evaluating the study methodology and summarizing the basic results. The references are also compiled based on geographic location to aid the user in identifying articles of particular interest.

Jan 1, 1994

By H. A. Schrecengost

Information presented herein was gathered by examination of 29 fluidized- bed thermal coal dryers and by conferences with manufacturers and users of such equipment to determine what safety features could be incorporated in design, installation, and operation to minimize fire and explosion hazards. Fire and explosion hazards are inherent in certain types of coal dryers in that high temperatures are employed; the sizes and volatility of material handled are capable of propagating explosions; and drying gases are seldom, if ever, low enough in oxygen content to prevent ignitions of dust clouds, distilled gases, or their combinations. This is especially true for fluidized- bed dryers in which the coal is dried in air suspension and in which atmospheric air is constantly introduced to temper the heated furnace gases. Occurrence of fires on heated bedplates, in dust collectors, and in hot gas inlets was common in nearly all the dryers examined. Forceful explosions which produced external effects had occurred in 11 (39 percent), and internal "puffs" or "bumps" had occurred in at least 24 (79 percent) of the plants examined in the study.

Jan 1, 1965

By N. N. Moelbs

The U.S. Bureau of Mines is conducting research on many topics relating to the hazards of coal mining, increased production, and protection of the environment. One area of research that has received scant attention in recent years is that of water inflows, probably because few fatalities in the United States have been attributed to them. As mining goes deeper, the problem of water in 1ow could increase dramatically because of adjacent or overlying mines in which huge water pools are impounded. Inaccurate mine maps and ineffective barriers can constitute a serious problem for operators both from gradual inflows and sudden inrushes of water. This report describes a wide but ineffective barrier that permitted an average 240-gpm inflow to a developing mine from an adjacent mine. The anomalous geologic structure that facilitated this leakage is described, demonstrating that size, alone, is no assurance against serious leakage. Some recommendations for managing serious water inflow are included.

Jan 1, 1989

By Thomas A. Phillips

An economic evaluation of the Bureau of Mines process for the separation of raw urban refuse into its metal, mineral, and energy components is presented. The process recovers ferrous metal, mixed nonferrous metals, aluminum, mixed-color glass cullet, and refuse-derived fuel products from raw refuse. Data for this evaluation were obtained from selected runs at the Bureau's pilot plant in Edmonston, Md. A cost estimate was prepared for a plant capable of processing 1,000 tons per day of raw urban refuse operating two shifts, 6 days per week. The fixed capital cost, based on second quarter 1976 equipment costs, is approximately $14.5 million excluding land and shipping containers. The estimated operating cost is approximately $8 per ton of refuse processed. This does not include credit for the products, transportation of the products, a tipping fee, or a dumping fee for wastes produced. No finance charges or taxes are included in the operating costs.

Jan 1, 1977

By Thomas Varley

"The literature on flotation of oxidized ores except for patents (especially for reagents) is very sparse. The Bureau of Mines in 1936, published a circular on the subject, by Ralston and Allen. The treatment of oxides by flotation was then in its infancy, but several of the most important mining companies in the Western United States and Mexico are now operating flotation plants for treating oxidized ores. The purpose of this present circular is to review the progress made and bring the subject up to date. One of the writers of the 1916 report (Mr. Allen) has been associated with some of the most important mining companies who have put into practical operation the process of flotation of oxidized ores; among these companies are the Shhttuck Arizona Copper Co., Bisbee, Arizona (now the Shattuck Denn Co.) and the San Francisco Mines of Mexico, Ltd., San Francisco Del Oro, Chihuahua, Mexico. His experience and other sources of information have been freely drawn on in pre-paring this paper. Mr. Ralston, assistant chief metallurgist of the Bureau of Mines, contributed many valuable suggestions and criticisms.Sulphidizing Reagents for Oxidize Ores.The various reagents and methods that might possibly be used for sulphidizing were summarized by Ralston and Allen as follows:""Sulphidizing (1) by the use of hydrogen sulphide on either the dry or the wet crushed ore, (2) by the use of solutions of the various sulphides and sulpho-compounds of sodium, (3) by the use of solutions of the various sulphides and sulpho-compounds of calcium, (4) by the use of sulphur vapor, (5) by the use of a sulphureted oil, (6) with colloidal sulphur."

Jun 1, 1927

By B. K. Shibler, K. C. Vincent, W. W. Agey

"INTRODUCTION As a part of the investigation of domestic manganese deposits, examining engineers of the Bureau of Mines collected samples of ore from three from three properties in the general vicinity of Tracy, Calif.The Buckeye mine is 23 miles of Tracy, just inside the northeast boundary of Stanislaus County. The mine is owned by K.O. Winship estate of San Francisco and is leased by Verner Allen, also of San Francisco.The ore is principally manganese carbonate occurring in interbedded layers in white chert, with the original,carbonate mineral altered in place. Four samples, representing four types of ore, were submitted, as follows: A, black oxide; B, pink carbonate; C, gray carbonate.The Wilfred Murphy property (also known as the Murmac claims) is approximately 30 airline miles south of Tracy. The property can be reached by road from either Livermore or Patterson and is on the divide separating Santa Clara and Stanislaua Counties Calif. The ore occurs in lenses along a white-chert formation. A 2-ton sample of ore for testing was taken from a dump accumulated from assessment and development work. The Ladd mine, 13 miles from Tracy in San Joaquin County is owned by Pat J. Connolly of Tracy and is leased by Mack C. Lake of San Francisco. The ore is essentially a chert impregnated with manganese oxides and the association is therefore exceedingly intimate and complex. Samples from each of the three adit levels of the mine were submitted for ore-dressing study.As the samples differed widely in physical character and response to ore-dressing methods of treatment, beneficiation of ores from each property was considered as a separate problem. Hence results of the investigations will be prescribed in separate sections of this report."

Nov 1, 1947

By Bernadette C. Michalski

Mineral raw materials, labor, capital, and technology form the basis of industrial production. The augmentation of one or all of the elements--labor, capital, and technology--will result in industrial growth. Thus, an increase in the labor force would increase output. A similar result would be achieved by expanding capital investment and supplying labor with more equipment. Finally, industrial growth can be achieved by introducing more productive methods and techniques born of technological advancement. The Soviet Union has employed these elements in many patterns to catapult from an agricultural to an industrial economy in four decades. The early history of the Soviet Union was marked by limited capital and borrowed technology, forcing the Soviets to concentrate on an abundant labor reserve to support the industrial program. The source of this reserve was the rural population. In [1928], 80 percent of the working population was employed in agriculture. This figure dropped to 43 percent by 1956, whereas industrial employment in the same period increased from 8 to 31 percent.3/

Jan 1, 1960

By Kevin Malone

Chrysotile asbestos occurs in many counties in California, and a small production had been reported at times, but development of deposits had been disappointing. A reconnaissance survey by the Bureau of Mines indicated that several deposits in the serpentine belt in Shasta, Trinity, and Siskiyou Counties might contain enough asbestos of filler grade to supply the growing demand on the west coast. Accordingly from 1956 to 1958 parts of the Mount Eddy and Shasta View deposits were investigated by trenching and diamond drilling to determine their potential. The work comprised construction of roads, bulldozer trenching, excavation of areas for diamond drilling, sampling, and upping. The trenches were excavated to expose the surface extent of some of the asbestos-bearing areas, To determine the downward continuation of asbestos-bearing sections and to secure samples for test purposes, six diamond drill holes, totaling 1,738 linear feet, were drilled in two selected areas. The trenching and core-drilling indicated that the asbestos-bearing material occurs as ribs and lenses of varying thicknesses in a broad belt of serpentine, about 600 feet wide and several miles long,

Jan 1, 1962

By Jr. Smith

The equilibrium compositions of product gases for mixtures of air with methane, propane, or ethylene at and around flame temperatures are reported. For each hydrocarbon, compositions are given for five fuel-to-air ratios--two lean, two rich, and one stoichiometric--at five pressures, from 1 to 20 atmospheres, and at an ambient temperature of 25° C.

Jan 1, 1965

By R. Hogg, S. Chander

"INTRODUCTION The behavior of particulate systems in general is determined by the properties of the solid and fluid phases and of the interfaces between them. As particle size is reduced, the inter facial effects become increasingly important until, in colloidal systems, they become completely dominant. Interfacial phenomena are especially important in coal processing for a variety of reasons. Because coal is naturally hydrophobic and its density is low, surface forces begin to dominate over gravity at relatively coarse sizes. Coal is thermodynamically unstable in the presence of air, so that surface oxidation occurs readily leading to important variations in surface properties with time and environment. These effects are further compounded by the inherent heterogeneity of the material.Surface characteristics and properties play a significant role in most aspects of coal processing. Comminution, for example, is a process of creating new surface, while agglomeration involves the reduction of surface area and is usually controlled by surface forces. Both solid-solid and solid-liquid separations are influenced by interracial phenomena, Gravity separations are usually performed in a liquid phase and are affected by the wetting characteristics of the various solids present and by the need to ensure proper dispersion of the individual particles. Froth notation, of course, separates particles on the basis of differences in surface characteristics. Chemical processes such as leaching generally involve interfacial reactions whose rates depend on surface area and may be influenced by electrochemical effects in the electrical double layer at the solid-liquid interface, or by adsorption of reactant and/or product species from solution. Solid-liquid separations and associated processes such as flocculation are strongly dependent on the nature and properties of the solid-liquid interface.In characterizing solid surfaces, it is important to consider first the surface area, since this determines the relative importance of the interfacial effects. The structure and chemical composition of the surface may depend on the distribution of different petrographic constituents and impurities such as finely disseminated mineral matter, on the extent of surface oxidation, and on adsorption from the environment. These, in turn, will generally determine the surface properties which define particle behavior. Since the relationships between structure etc. , and properties are not generally known, it is usually necessary to measure properties such as wettability and electrical charge directly."

Jan 1, 1989