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By William C. Cooley

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Jan 1, 1975

By Alexander May

The U.S. Bureau of Mines investigated the application of oxidation-reduction potential (ORP) and pH measurements to environmental studies of mining and mineral processing wastes, and developed a computer program to estimate the concentrations of species of lead present in samples from a lead processing waste site. The methods and techniques for the ORP-pH measurements were investigated using known standard solutions made in the laboratory, samples from a ferric oxide waste disposal pond at a rutile production plant, and samples of well water and stream water from the lead processing waste site. ORP values were measured from 5 to 80 °C, from pH 1 to pH 12, and at various ratios of oxidant to reductant. The ORP-pH values can help identify valence values and species of ions present, including those of major, minor, and trace concentrations, and also indicate possible reactions at various pH values. The ORP measurements versus temperature yield data from which thermodynamic values can be calculated. The application and limitations of these measurements are discussed, and a brief discussion of the computational program to identify species of lead is presented.

Jan 1, 2010

By Thomas V. Falkie, R. Venkataramani

The method of analysis was to test a large model containing potentially significant variables and on the basis of the results obtained, to reduce the model to one containing only the essential significant variables. This stepwise procedure of "scanning" a large proposed model and subsequently condensing the model consisted of two cycles of the same series of computational procedures. Data Preparation A majority of the variables measured were continuous over a specific range of values; for example, the variable "Width Ratio" varied in practice from 0.25 to 1.00. However, "dummy" values were assigned to certain operational variables in order that these varia¬bles would have numerical expression. The following variables were described in this manner. Variable "Dummy" Value x3: Development/Pillaring 0, if pillar extraction was being done 1, if development mining was being done x4: Boxcut/Open Cut 0, if a box cut was being made 1, if an open cut was being made The variables under consideration are represented symbolically as follows: Y: Loading rate (tons per minuts): TONS/MIN x1: Ratio, width of cut/width of cutter: WDRATIO x2: Ratio, height of cut/diameter of cutter: HTRATIO x3: Development or pillaring: D/P

Jan 1, 1972

By Albert L. Brautigam, Michael C. Leigh, August J. Kwitowski

The U.S. Bureau of Mines developed and tested a teleoperating system to control a new highwall mining system. A remote operator was provided out-of-sight sensory information and control of coal extraction and haulage equipment. Surface and production testing proved that the teleoperating system supplied the operator with sufficient sensory information to operate the mining system. Details on the teleoperating system provided in this report include (1) sensor selection, (2) a description of the electronic control system, (3) equipment selection and modifications, (4) the positive test results, and (5) recommendations for system improvements.

Jan 1, 1992

By Gordon T. Austin

The combined value of production of natural abrasives, which include tripoli, special silica stone, garnet, staurolite, and emery, decreased about 24% in 1992. The decrease in the value of tripoli production was the result of a decrease in total production. Emery decreased owing to a decrease in the volume of the material produced. Special silica stone experienced a significant increase in unit value and decrease in the quantity produced. Garnet showed a 6 % increase in quantity and a 36 % decrease in unit value. Staurolite decreased about 27 % in the quantity produced and value compared with those of 1991. The fused aluminum oxide industry showed a slight increase in the quantity produced and a 4 % increase in the value of production. The silicon carbide industry saw a 7 % increase in the quantity produced and a 10 % increase in the value of production. Combined, the industries increased 4 % in quantity and 6 % in value compared with those of 1991.

Jan 1, 1992

By C. D. McMaster, John C. Hartley

Three systems that monitor ventilating fans are described . These electronic monitoring systems automatically perform most of the operations required to conform with the provisions of the Federal Mine Safety Code in the event of fan failure or slowdown .

Jan 1, 1964

By A. Wahab Khair, N. P. Reddy

"Abstract. This paper attempts to characterize coal breakage due to the action of a continuous miner. Coal blocks with an approximate dimension of 45.7 cm x 38.1 cm x 15.2 cm (18 in. x 15 in. x 6 in.) were first subjected to confining pressures equivalent to in-situ conditions. Then the blocks were cut along the face/butt cleat direction by the cutting head of a specially designed unique automated rotary coal cutting simulator (ARCCS), simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-sit and operating parameters a number of other para¬meters such as 1) penetration of bit into coal, 2) penetration resistance (thrust and cutting pressures), 3) rotating velocity of cutting head, and 4) acoustic emission activity in the coal block were monitored. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted by using a sonic technique. At the end of each experiment, the coal fragments were collected in bags using a vacuum cleaner. These fragments were then sieved for size distribution analysis.INTRODUCTIONThe Federal Coal Mine Health and Safety Act of 1969 was enacted to emphasize to coal operators that the airborne respirable dust should not exceed 2 mg/m3, thus reducing the incidence of coal workers pneumoconiosis.Dust control techniques such as conventional water sprays and dust collectors are only partially effective and require additional equipment expenditures. A more authentic approach would be to reduce respirable dust at the source the continuous mining machine cutting head, where the fragmentation process occurs. Improving the fragmentation process by characterizing the coal breakage will not only reduce respirable dust at the face, but it will also decrease the amount of respirable dust that is liberated during the secondary handling.Fragmentation of coal can be expressed as a function of three major groups of parameters; namely, 1) coal properties, 2) in-situ conditions and 3) operating parameters. This paper deals with the characterization of coal breakage along both face/butt cleat direction as a function of machine operating parameters such as rate of advance, angle of attack, bit configuration, bit lacing (spacing and pattern) and bit speed at various equivalent in-situ pressures."

Mar 1, 1989

By W. P. Diamond

It is estimated that more than 1 trillion cubic feet of methane is contained within the coals of the Mary Lee group in Jefferson, eastern Tuscaloosa, and southern Walker Counties, Ala. Most of this methane will be encountered by mining. Coals of the Mary Lee group are presently being mined at depths exceeding 1,000 feet and will in the near future be mined at even greater depths, where the problem of methane gas affecting the mining operations will be acute. It is calculated that approximately 90 pct of the methane is at depths greater than 1,000 feet, and over half of the gas is contained within only 12 pct of the study area which is under more than 1,500 feet of over-burden. Degasification in advance of mining will increase mine safety, reduce ventilation expenditures, increase productivity, provide an additional energy source, and make it possible to mine parts of deep coalbeds that probably could not otherwise be mined.

Jan 1, 1976

By C. W. Davis

This paper is the second of a series of progress reports on a study, of the hydrometallurgy of manganese which is being conducted in an endeavor to make possible utilization of the large deposits of low-grade domestic manganese ores that occur in several States. There are at least four processes in which a knowledge of the action of SO2 gas on manganese oxides at elevated temperatures may prove of value. One ,of these involves dissolution of manganese from ores. The Bureau of Mines has investigated the hydrometallurgy of manganese by a process in which SO2 gas, a waste product at many smelters, is passed into water to form a solvent for manganese. Although Several manganese minerals acre readily dissolved, rhodochrosite (MnCO3) was attacked but superficially.§. Recent experiments have shown that a roast at 650 to 900°C converts the manganese of rhodochrosite to a form that is quickly dissolved by a weak SO2 solution. Introduction of smelter gases containing as much as 5 per cent SO2 during such a roast would not add much to the cost of the operation and might result in the formation of considerable water-soluble manganese sulphate.

Jan 1, 1930

By Earl L. Hastings

Although the principal market for diatomite in the United States is in the East,4 production of the material is presently restricted to the West, because the deposits are larger, mining costs are cheaper, and the quality of product is better than that obtained from other domestic deposits. However, Tallahatta diatomite, occurring in Choctaw and Clarke Counties, Ala., has a freight rate advantage, which should encourage competition for those market that are now being supplied with the purer diatomites from the western deposits. For this reason, diatomite occurrences in the Tallahatta formation were examined by the Bureau of Mines and physical properties of samples from the deposit were determined to obtain additional data for use by any potential producer who wished to evaluate the material for its commercial possibilities. In 1894 K. M. Cunningham5 found that the buhrstone formation (now known as the Tallahatta formation) contained "siliceous shells of marine diatoms, radiolaria and foraminifera, thus being rather of the nature of tripoli or diatomaceous earth than of a true clay." Cooke6 and Semmes7 also reported the Tallahatta formation to be composed principally of diatomaceous earth with accompanying beds of sand, clay, and sandstone.

Jan 1, 1963

By Thomas Varley

"Concentration, ore-dressing, or the dressing of minerals are common terms used in metallurgy and indicate processes of separating valuable minerals from worthless gangue. It is understood, of course, that the products from such processes, being separated from the various minerals and gangue, are ready for commercial sale or for further treatment by smelters and refineries.Gravity concentration takes advantage of the difference in specific gravity of the various constituent minerals and gangue of waste material in the ore. The two most common forms of concentration by this means are jigging and table concentration. Jigs usually are used in the separation of relatively coarse material and the tables for the finer material, the line of division in general being about 20 mesh.There are mar factors to be considered .before a decision can be made as to what method would be best adapted to the successful treatment of an ore and only by careful experiments can this be determined. Among the important factors to be considered are. The nature of the minerals present, their physical and chemical relations to the gangue material, and the gangue material itself. Perhaps the most important is the number of minerals present and their relation to each other.Metals exist in ores in three principal forms -- sulphides, oxides or carbonates, and native. Concentration by gravity methods is in general best suited to sulphide ores, although in some places considerable success has, been obtained in the concentration of oxide ores by gravity methods."

Apr 1, 1920

By Edward A. Barrett, Roberta A. Calhoun

Introduction This Instructor’s Copy contains most of the materials trainers will need in order to use Drill Rig Incident (DRI). It includes suggestions for using the exercise, performance objectives for the training, master answer sheets, a scoring key, and a set of discussion notes that provides additional subject information. Four appendices are also included. Appendix A is the complete exercise problem booklet. It may be reproduced so that every person in the training class has one. Appendix B contains answer sheet blanks. The blanks are furnished if you choose to have the invisible ink answers that appear in appendix C printed on them at your location.3 Answer sheets are consumable. One is needed for each group of three to five persons who work the exercise together. An alternative is for each individual trainee to have his/her own answer sheet. Appendix D contains the 24-question pretest / posttest that was used in the field evaluation of the DRI exercise. Acknowledgment The authors thank Linda J. McWilliams, Statistician, NIOSH Pittsburgh Research Laboratory, for her assistance in analyzing the experimental data in this document.

Jan 2, 2005

Improve the safety of roof bolting machine operators working in underground coal mines while maintaining or improving efficiency of the roof bolting operation. Approach The Bureau of Mines funded research under contact to develop equipment that would assure greater safety in drilling holes and installing roof bolts. The research led to the design and fabrication of a roof-boiling machine that allows its operator to per-form drilling and bolting tasks while under permanently sup-ported roof or canopy protection. How the Prototype Works The major components of the remote-control roof bolter are a flexible-shaft drill that provides continuous drilling capability without the need to Stop to add drill extensions for long holes; a roof-bolt inserter that can bend a longer-than-seam height roof bolt into the drilled hole; and a roof-bolt lifter/torquer that completes insertion of the roof bolt into the hole and torques it to the desired tension.

Jan 1, 1986

By W. T. Wertman

LABORATORY research has been started at the Bureau of Mines Morgantown Petroleum Research Laboratory, Morgantown, Va., to investigate the possibilities thermal-recovery methods for producing crude oils of high API gravity found in oil reservoirs of the eastern United States. This bibliography on thermal methods of oil recovery was compiled as a part of the work. Crude oil discoveries to December 31, 1958, in the United States were estimated to exceed 270 billion barrels. Cumulative production of crude oil through 19.55 was about 60 billion barrels, and the American Petroleum Institute estimates that an additional 30.5 billion barrels are economically recoverable by present methods. On this basis, about two-thirds of the oil that has already been found can be classified as economically unrecoverable for lack of a satisfactory method. The rap icily rising costs of proving new deposit; of domestic petroleum, the lack of new discoveries of large oilfields in the united States, and I he growing demand for crude oil have caused an acceleration of research to develop new or improved methods fur producing "unrecoverable" oil in known reservoirs.

Jan 1, 1960

By R. H. Lien

The Bureau of Mines investigated a roast-leach process for recovering a marketable lithium product from a montmorillonite-type clay deposit located on the Nevada-Oregon border. The clay sample treated in the investigation contained 0.6 wt pct Li. The lithium recovery process consisted of several unit operations. The lithium silicate compounds in the clay were converted to Li2SO4 by roasting a pelletized mixture of clay, limestone, and gypsum at 900° C in a direct-gas-fired rotary roaster. Water--leaching the calcine at 40 pct solids extracted the Li2SO4. Lithium recovery from the leach solution involved concentrating the solution by evaporation, adding Na2CO3 to the concentrated solution to precipitate Li2CO3 , and filtering the slurry to obtain the product. The product filtrate was recycled to the evaporator following a crystallization step. About 80 pct of the lithium in the clay was recovered as 99-pct-pure Li2CO3. Process operating costs were estimated at $2.12/lb Li2CO3 produced; the current Li2CO3 selling price is $1.48/lb. Raw materials. accounted for 30 pct of the total operating cost.

Jan 1, 1985

To develop a quick, safe, and effective method that allows workers at mineral processing operations to clean their dust-soiled clothing periodically throughout the workday. Background Reducing workers' respirable dust exposure to silica and other harmful dusts and contaminants is an ongoing goal in the U.S. mining industry. One area of known worker exposure is from contaminated work clothes. A U.S. Bureau of Mines report documented a number of cases where a tenfold increase in a worker's dust exposure was measured from contaminated work clothes. In these cases, the dust emitted from clothing caused the worker's dust exposure to exceed the permissible exposure limit in less than 2 hours. The most effective way to eliminate this dust source is to have workers clean or change their work clothes. There are two federal regulations that impact the clothes-cleaning process. The first states that at no time shall compressed air be directed toward a person, but that when compressed air is used, then all necessary precautions shall be taken to protect persons from injury. The second regulation states that compressed air should only be used for cleaning purposes when it is less than 30 psi and used along with personal protective equipment. For the mining industry, by default, the only approved method to perform clothes cleaning is to have workers vacuum their clothes using a HEPA filter system. This is very difficult and time-consuming and, in most instances, not very effective. Most workers would prefer to use a single compressed air hose to blow dust from their work clothes. However, not only is this method prohibited by law, it usually creates a significant dust cloud in the work environment and contaminates coworkers.

May 1, 2005

By W. K. Sawyer

Resistivity, porosity, permeability, and saturation data were obtained on core samples from the Big Injun, Clinton, Gordon, Bradford Second and Third, and Venango Second oil sands and formation factor-porosity relationships were derived using the general form of Archie's equation F = aø-m, where F is the formation factor, ø is the porosity, and a and m are constants that depend on characteristics of the rock. It was found that a and m varied significantly between sands, as did the exponent in the Archie relation I = Sw-n, where I is the resistivity index and S, is the water saturation. The average exponent, n, determined from all data was 50 percent greater at residual oil saturation than at residual water saturation. Samples from each sand exhibited differences in directional resistivity and/or permeability. The Bradford Third sand data showed correlation between resistivity and permeability anisotropy.

Jan 1, 1971

Provide a low-maintenance, reliable means of generating bubbles and controlling bubble size for column flotation. Approach Commercial sparger systems used in flotation columns to process minerals provide only limited means of controlling the size of bubbles generated and the rate of air injection. Generally, these limitations are a detriment to flotation performance, particularly in recovering coarse or fine mineral particles. In addition, conventional bubble generation systems require frequent maintenance, often requiring shut-down of the column itself for repairs. To permit greater control of the bubble size generated in the flotation column and to eliminate the counter-productive problems associated with the operation of current air sparger systems, the Bureau of Mines investigated alternative methods for generating bubbles. Based on the investigation, an external bubble generation system was designed, developed, and laboratory and commercially tested.

Jan 1, 1987

By A. A. Giardini

This report represents the results of a literature study on boron nitride and related substances. The purpose of the study was to find Information that might be of value for production of a new, hard modification of boron nitride preferably in single crystal form. The report consists of a review of the major developments in boron nitride research, a discussion of the results, tabulations of physical and chemical properties;, conclusions drawn from the study, and a bibliography.

Jan 1, 1953

By W. L. Staker

Alternatives were developed to the conventional ammoniacal carbonate leaching-steam stripping procedure for recovering copper as an oxide from contaminated scrap metal. By entraining air bubbles in the leach solution, the copper dissolution rate was increased to 1.5 g/in2 of copper surface per hour, compared to 0.5 g/in2/hr produced by conventional agitation in stirred tanks. Using entrained nitrogen gas bubbles for agitation in conjunction with powdered sulfur not only resulted in rapid dissolution but also simultaneous precipitation of the copper from solution as a high-grade cuprous sulfide.

Jan 1, 1971