Search Documents

By W. K. Overbey

Surface fracture trace density, changes in roof rock type, and topographic unloading due to drainage were mapped for the mining areas located in the Blacksville-Osage, W. Va., quadrangles to investigate their influence on mine roof falls. Using these factors, a technique was developed to predict probable roof fall areas ahead of projected mining operations. As a feasibility test of this proposed technique, areas were delineated where one, two, and all three of these factors were operating to formulate a "potential hazard map" for comparison with roof fall observations that were made. The limited evidence suggests that in combination these factors are reliable predictors of where roof falls are likely to occur. This technique promises to be a useful tool in planning mining operations.

Jan 1, 1973

By John W. Finch

The present epoch in human history has been variously described as the age of coal, of oil, of iron and steel, and of power. All agree, however, that it is a great industrial period. Power is of course the vital force in the industrial organism; but power is derived chiefly from mineral fuels or from harnessed and controlled water - also a mineral substance although usually not so classified by industry. However, the latent energy of fuels cannot work for men until it is changed to active energy by combustion and until this active energy is converted into motion. This motion is just as indispensible as the energy itself. Likewise, the latent energy of water cannot be utilized until it, too, is converted into motion; out the mechanisms and devices for converting latent energy into motion, as well as the structures in which they are operated, would not be possible without metals and other minerals. Consequently, minerals are fundamental in industrial civilization.

Jan 1, 1938

By Paul M. Tyler

Graphite is chemically identical with diamond, both being crystallized allotropic forms of carbon. Graphite obviously differs greatly from diamond in physical properties and is easily recognized by its blackness, its softness (1 to 2 on Mohs' scale), and its slick feel when rubbed between the fingers. Strictly speaking, all graphite is crystalline, but grades in which the individual grains cannot be distinguished with the naked eye are commercially classed as amorphous. Natural mixtures of the two varieties occur in all proportions, and the classification of a given sample as "amorphous" or "crystalline" graphite is based largely upon trade practice. Until recently different varieties of vegetable or animal charcoal, lamp black, soot, gas carbon, and coal ware considered strictly amorphous, but modern examination by X-ray methods indicates that even these materials possess the same internal crystalline structure as graphite, differences in physical properties being perhaps explained by porosity or presence of combined hydrogen or other impurities.

Jan 1, 1941

By Walter R. Storms, Allan B. Bowman

This paper , which describes mining methods and practices at the Mineral Hill copper mine , is one of a series being prepared by the Division of Minerals of the Bureau of Mines on mining methods , practices , and costs in various mining districts. of the United States . The Mineral Hill mine is situated on the northeastern piedmont of the Sierrita Mountains at an altitude of 3,650 feet in sec . 35 , T. 16 S. , R. 12 E. , and sec . 2 , T. 17 S. , R. 12 E. , Pima mining district , Pima County , Ariz . ( fig . 1 ) . The claims (figs . 2 and 3) are in a gently rolling area with only scant desert vegetation . The average annual precipitation is about 11 inches . The nearest surface water is the Santa Cruz River , an intermittent stream 8 miles east of the mine . The property is owned by the Banner Mining Co. , a Nevada corporation . This report presents a brief history of the mine , describes the geology of the area and the ore deposits , outlines methods of prospecting and exploration , and gives methods of sampling and the estimation of ore reserves and values . Development and stoping methods are explained , and methods of underground transportation , ventilation , mine drainage , and safety measures are described . The concluding section of the paper is a section on milling . The Mineral Hill mine is an old mine that was reopened in 1951 after having been closed for 30 years .

May 1, 1957

By Forrest T. Moyer

In conjunction -with the statistical survey of the lime industr-.r in 1939, by the Bureau of Hines, producing companies reported the lime-fuel ratios attained in their plants according to type of kiln and kind of fuel. Each ratio, expressed as the number of pounds of lime burned by a unit quantity of fuel, was weighted according to the tonnage of quicklime pro- . duced at the reporting plant and grouped with similar data from other plants, so that an average ratio for each type of fuel and,kiln could be calculated. By this method the variables trat affect ratios of individual plants are more or less equalized, and the computed average lime-fuel ratios provide a fair measure of kiln and fuel efficiencies during 1939.

May 1, 1941

By J. D. McLenegan

The purpose of this investigation was to prepare a market survey of the refractories industry in California and Nevada (referred to in subsequent paragraphs as the region), and to determine the degree of self-sufficiency and the potential capacity for anticipated growth. The report includes estimates of the total annual refractories consumption, the quantity of refractories imported into the region, the tonnage of raw materials required for their manufacture, and the resources of fire clay and high-alumina minerals in the region.

Jan 1, 1956

By E. J. Matson

The Little Castle Creek chromite deposit was examined in February and May 1941, respectively, by W. O. Vandenburg and O. H. Metzger, engineers of the Bureau of Mines. The Federal Geological Survey started a magnetometer survey of the area in November 1940 and completed its work during April and May 1941. Field work by the Bureau of Mines was conducted during May and June 1941. The purpose of the Bureau of Mines investigation was to search for a continuation of the chromite mineralization. The property at one time was the largest chromite producer in California.

Jan 1, 1949

By Oliver Q. Leone

The effect of oxygen content in the anode metal on titanium electrorefining characteristics was studied. Increasing quantities of oxygen in the anode resulted in increased anode scale formation, decreased anode and cathode current efficiencies, lower titanium recovery efficiencies, and higher oxygen content of the cathode products. The titanium electrorefining process performed best when the anodes did not contain more than 0.5 percent oxygen, although anode dissolution was recorded for alloys containing up to 25 percent oxygen. Back emf affords a useful index of an alloy to electrorefining.

Jan 1, 1965

By A. B. Hooker

[Permissible electric cap lamps represent a workable balance between the amount of light needed and the various limiting conditions, such as the weight the miner can carry conveniently, cost of the lamp, including upkeep, and adequacy or practicability of the lamp as regards safety, mechanical strength, and general performance. Other things being equal, the coot desirable lamp is one that gives the greatest amount of useful light. Conversely, with a given amount of light the most desirable lamp is one that its the most efficient respecting weight, cost, and performance.]

Jan 1, 1935

By A. B. Hooker

[Permissible electric cap lamps represent a workable balance between the amount of light needed and the various limiting conditions, such as the weight the miner can carry conveniently, cost of the lamp, including upkeep, and adequacy or practicability of the lamp as regards safety, mechanical strength, and general performance. Other things being equal, the coot desirable lamp is one that gives the greatest amount of useful light. Conversely, with a given amount of light the most desirable lamp is one that its the most efficient respecting weight, cost, and performance.]

Jan 1, 1935

By Charles D. Litton

An overview of state-of-the-art technology in fire detectors is presented by the Bureau of Mines regarding their use in the mining industry. Detectors are categorized according to the characteristics of a fire to which they respond. Operating principles of the various detectors, their application, and the advantages and disadvantages of each are discussed.

Jan 1, 1979

By E. P. Youngman

This paper is 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 right of American citizens to explore for minerals and to own and operate-mines in various foreign countries. This interpretation of the mining laws of Greece was prepared from information furnished by Ralph B. Curren, American assistant commercial attache, Athens, in reply to a questionnaire of the United States Bureau of Mines, transmitted through the courtesy of the commercial laws division of the Bureau of Foreign and Domestic Commerce. INTRODUCTION In his report,3 Mr. Curren states that the source of his information was the Director of Mines of the Greek Ministry of National Economy and the Mining Code of Greece, which was, compiled from existing laws in 1929,4 and which has since been modified by several acts of Parliament.

Jan 1, 1932

By Alan D. Hartman

The U.S. Bureau of Mines, under a Memorandum of Agreement with the American Society of Mechanical Engineers (ASME), established design criteria for a facility to melt residues from municipal waste combustion. This facility, which is available to potential users on a cost-sharing basis, is also applicable to a variety of inorganic waste materials from smelting or melting operations. The design consists of a mechanical feed handling system, electric arc melting furnace, fume-offgas handling system, and thermal oxidizer for final offgas treatment. Screw conveyors and a bucket elevator deliver up to 2,000 lb/h of minus I-in material to a three-phase electric arc melting furnace. This unique 800-kV?A furnace has a water-cooled shell and roof to minimize interaction of the melt with the refractory lining. The volume of the hearth below the slag taphole is approximately 1.2 st of steel. The furnace is sealed, allowing atmosphere control within the furnace and fume duct by nitrogen or inert gas injection. A jet-pulsed baghouse removes particulate from the offgas and serves as an acid gas scrubber. The clean offgas is heated to 1,800° F for 1 s in a propane-fired thermal oxidizer before being vented to the atmosphere.

Jan 1, 2010

By A. J. Keast

This circular is one of a series dealing with the exploration, equipping, and development of mining properties, prepared and published by the United States Bureau of Mines in cooperation with various mining and exploration companies in the United States and Canada. This series of papers will supplement an earlier one which covered the methods and costs of mining and milling at a large number of producing mines. The present paper describes the exploration, equipping, and developing of a group of 18 claims remote from rail transportation, and the transport of equipment and heavy supplies for a distance of 120 miles by tractor over ice and winter roads, and of men and lighter supplies by airplane.

Jan 1, 1933

By F. R. Cattoir, D. H. Baker

Fused - salt electrorefining has been successfully applied to the purification of vanadium metal . The electrolyte used in this refining technique was sodium chloride to which had been added 3 to 6 percent vanadium as vanadium dichloride . The average deposition current efficiency was 91 percent . Oxygen and nitrogen , the impurities in commercially produced vanadium metal , were reduced by two - thirds of the amount contained in the feed material . Hardness of the vanadium- metal product was reduced from an initial 97 Rockwell B ( RB ) to a minimum of 35 Rg . The reduction of these impurities markedly improved the plasticity of the final product obtained by melting the crystalline cell metal into small ingots . These ingots could be given a 99 - percent cold reduction by rolling before edge cracking appeared . Growing interest in high - purity vanadium and the industrial need for purer metals and improved alloys for use under high temperatures and high speeds have demanded the elimination and/or control of impurities . Accordingly, research to eliminate or control the undesirable impurities has been expanded .

Jul 1, 1960

By S. H. Lorain

This paper is one of a series on mining and milling method and costs being published by the United States Bureau of Mines. The Golden Messenger mine, operated by the United Gold Mines Corporation, is in the York-Confederate Gulch mining region in Luis and Clark County, Mont., 22 miles northeast of the city limits of Helena and about 1 mile north of the town of York. It is the first operation to exploit successfully the low-grade ores of the York-Confederate Gulch area. The unusual vein structure presents some mining problems that have been solved in ail interesting manner.

Jan 1, 1937

By Perry G. Cotter

As a portion of a general program for the synthesis of hard materials, a method was sought by which the hardness and density of tungsten carbide (WC)-cobalt compacts could be increased. It was demonstrated by Cotter that these improvements in quality could be made by employing an electric-resistance sintering process in which heat and pressure are applied simultaneously to presintered compacts composed of powdered tungsten carbide and cobalt. This conclusion was based on tests of material prepared by Cotter on welding equipment in use at the U. S. Naval Engineering Experiment Station, Annapolis, Md., and at Rensselaer Polytechnic Institute, Troy, N. Y. Rockwell-hardness tests made at Norris and core-drilling tests made at the Mount Weather Station of the Bureau of Mines indicated that, for some purposes, carbide material made by this process might be superior to the chemically analogous commercial products prepared by ordinary sintering methods. A program to develop optimum conditions for the electric-resistance sintering of tungsten carbide-cobalt compacts was initiated. The program was followed by a systematic evaluation of the hardness and density of compacts prepared by this method along with a series of carbide compacts furnished by various manufacturers. This paper presents a description of the electric-resistance sintering of tungsten carbide-cobalt compacts and the results of comparative physical tests.

Jan 1, 1955

By Robert S. Sanford

This paper deals with truck haulage methods and costs at one of the many open-cut mines that are replacing rail haulage with heavy-duty trucks. At this mine, ore is trucked to a crushing plant, centrally located within one of the open-cuts. The requirements for efficient low-cost truck haulage are: Good trucks designed for heavy loads, adequate truck maintenance, smooth roads, and well-trained truck drivers The weighted average cost of hauling a long ton of ore to the crusher and the waste to the dump was reduced from $0.1993 in 1948 to $0.1114 during the last half of 1949, his corresponds to a cost per ton mile of $0.0864.

Jan 1, 1952

By Gregory Krohn

This report investigates the effects of adding a layer of extra padding to the palm area of leather gloves typically worn by low seam coal miners. The first study showed that added glove padding provides more potential protection but does not affect manual dexterity. The second study, in a simulated low seam coal mine, showed no significant differences using padded and non-padded gloves in crawling, shoveling, timbering, and cart pushing task completion times. In general, subjects preferred the padded gloves although they expressed some complaints about awkardness and loss of sensitivity. Recommendations are given for the design of padded gloves that will provide comfort, protection, and maximum hand sensitivity for miners.

Jan 1, 1980

By C. L. Chaney

Investigations were conducted to develop spectrochemical methods capable of determining 0.01 to 100 micrograms of metals in 50 milliliters of solution. The use of gallium hydroxide (Ga(OH)3) as a carrier-precipitant to concentrate metallic ions is described. A porous-cup graphite electrode is used to collect the precipitate. A specially designed plunger permits the electrode assembly to serve as the sample-containing electrode in the subsequent spec-trographic analysis. Analytical curves are presented for antimony, arsenic, beryllium, and zinc. Sensitivities of detection are given for 13 elements. The techniques were applied to identify impurities separated from tungsten, to determine trace impurities in solutions containing high concentrations of magnesium, cobalt, or nickel, and to identify trace impurities in hydrofluoric acid. Laboratory glassware was a serious source of contamination when low levels of zinc were determined.

Jan 1, 1963