Search Documents

By F. D. DeVaney

The low-grade deposits of manganese ores along the Missouri River near Chamberlain, S. Dak., are known to contain one of the largest reserves of manganese in the United States. Manganese occurs as concretionary nodules ranging in size from 13 inches in their longest dimension to particles finer than 65-mesh. The nodules are embedded in soft, wet shale, which contains little manganese. The removal of nodules from the low-grade shale is a simple mechanical -problem; the question is primarily to determine the lowest-cost method of separation. This report purposes to present data acquired by experimenting with samples of the ore, which form a basis for suggesting methods of concentrating manganese nodules.

Jan 1, 1942

By F. D. DeVaney

The low-grade deposits of manganese ores along the Missouri River near Chamberlain, S. Dak., are known to contain one of the largest reserves of manganese in the United States. Manganese occurs as concretionary nodules ranging in size from 13 inches in their longest dimension to particles finer than 65-mesh. The nodules are embedded in soft, wet shale, which contains little manganese. The removal of nodules from the low-grade shale is a simple mechanical problem; the question is primarily to determine the lowest-cost method of separation. This report purposes to present data acquired by experimenting with samples of the ore, which form a basis for suggesting methods of concentrating manganese nodules.

Jan 1, 1942

By L. L. Hirst

Liquid fuel oils possess certain advantages over solid fuels. Ease in handling, precision temperature control, and almost complete freedom from ash are among those considered when a liquid fuel is selected for use in industrial processing. In some instances these fuels are desirable because more heating units can e packed in a Given space where space is limited, as on snips. In other cases the' are chosen because of lower actual cost per British thermal unit absorbed, or for control of the flame to increase the capacity of furnaces, as in steel and refining.

Jan 1, 1948

By John A. Breslin

This report summarizes the principal activities and significant results of the Bureau of Mines respirable dust research program since passage of the Federal Coal Mine Health and Safety Act of 1969 and the Federal Mine Safety and Health Amendments Act of 1977. This program has investigated new and improved techniques and equipment to reduce or prevent the formation of dust during the cutting cycle; to dilute, suppress, or collect airborne dust generated during mining, handling, and processing; and to improve the measurement of dust levels for evaluation of engineering controls and for enforcement of Federal dust standards. The report is intended for mining industry dust control specialists and other interested parties. It includes a brief summary of the program to date, a section on future research plans and goals, and a list of publications resulting from the Bureau's respirable dust program.

Jan 1, 1982

By R. S. Dean, John Gross

"In a preliminary report made a year ago it was shown that certain minerals when subjected to heating with water under high pressure and temperature were shattered upon the sudden release of that pressure. The main feature in which the results of this method differ from those of conventional grinding is in the differential effect obtained. The more metallic minerals, and hence the valuable minerals, are shattered more readily than are the gangue minerals. In other words, explosive shattering is unique among possible methods for comminuting an ore in that it wastes the least energy on the useless part of the ore. Explosive shattering, therefore, offers possibilities as a means for reducing grinding costs, arid it is this potential advantage of the process that makes it worthy of further experimental study. The first part of this paper is devoted to a study of the mechanism of the process; the, second part reports results obtained in toots on a selected list of ores to exhibit some of the advantages of explosive shattering."

Feb 1, 1933

By P. B. Altringer

The Federal Bureau of Mines conducted a study to determine if residues from fractional distillation represent a potential source of mineral values. A literature review and discussions with tar sand specialists failed to disclose the mineralogical nature of residues remaining after bitumen extraction. To develop this information, pilot plant tar sand residues or toluene-cleaned tar sands from 23 deposits were examined. The nature of the residues was determined by standard mineralogical methods and the chemical compositions were determined by X-ray and ICP (inductively-coupled plasma spectroscopy). None of the sands or concentrates examined contained sufficient valuable minerals to be economically important.

Jan 1, 1982

By A. L. Worthen

This is one of a series of pacers being published by the United States Bureau of Mines, describing mining and milling methods at crushed-stone plants throughout the United States. These pacers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total production costs. Although the publication of total production cost might not be advisable in some instances, yet a knowledge of operating costs is essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called o this differentiation in order that there will be no misunderstanding of the scope of the cost tabulations. This paper deals with the quarrying and crushing methods used at the Plainville plant of the New Haven Trap Rock Co., which produces annually between 275,000 and 300,000 tons of trap rock, Although pct the largest quarry operated by the company, it typifies the standard methods used by all the quarries in producing crushed stone and has one or two rather unique operating features. The cost of production at this plant is close to the average cost at all quarries of the company.

Jan 1, 1936

By Charles A. Kumke

In June 1942 , ' the Bureau of Mines selected the Zonia copper mine , near Kirkland , Yavapai County , Arizona , as a property meriting investigation in connection with its search for supplies of strategic minerals for use in the war . The following month , representatives of the War Production . Board conferred with Bureau officials and requested that the property be explored with the object of determining the tonnage and grade of ore that could be brought into production quickly and mined cheaply by open-pit methods . The work wa's designed to verify information submitted by the owners in support of an application for a Government loan. It was essential that the investigations be completed promptly , so that operations might be planned and copper produced for war needs . The investigations called for surface trenching , diamond drilling , and check sampling of underground workings . Unable to purchase equipment for trenching without considerable delay , the Bureau saved time by borrowing most of the necessary items from the Golden Queen mine of the Gold Fields Development Co. at Mohave , Calif. This company , whose engineers had sampled some of the old trenches , had a tentative agreement with the owners to operate and manage the Zonia mine in event the loan was granted . Additional equipment was borrowed from two Governmental agencies . The exploratory work , completed in 16 weeks , was carried on 7 days a week .

Mar 1, 1947

By Joseph M. Kuchta

The limits of flammability and minimum autoignition temperature of a fuel are important elements in assessing fire and explosion hazards that may exist when using or handling the fuel. The limits of flammability define the range of compositions of the fuel gas or vapor mixed with an oxidant through which a flame, initiated by an outside energy source such as an electrical spark, can propagate. The minimum autoignition temperature (M.A.I.T.) is the lowest temperature at which the fuel vapors ignite spontaneously in a specified medium; in this case the ignition energy is supplied by the heat content of tae environment. This temperature is also referred to as S.I.T. value by some authors. Because the autoignition of a fuel also depends on the time interval during which the fuel is subjected to heat, ignition delays are significant. Ignition delay is defined here as the total time elapsed between the introduction of the liquid fuel into the oxidizing atmosphere and the appearance of a flame. This time interval includes both the physical and chemical processes leading to ignition. The ignition delay is usually maximum at the M.A.I.T, and decreases as the temperature of the system is increased. The flash point and the fire point are also useful in assessing the fire and explosion hazards of a fuel. The flash point is the lowest temperature at which saturated, flammable fuel vapor-air mixtures are formed at atmospheric pressure and, therefore, it is essentially the lower limit of flammability

Jan 1, 1962

By K. J. Liles

The Bureau of Mines conducted laboratory semicontinuous and continuous heavy liquid tests to determine the feasibility of producing commercial-grade products from the high-clay sylvinite ores of the Permian Basin in New Mexico. Continuous test operations demonstrated that concentrates containing 59.9 percent K2O and recoveries of over 75 percent of the contained potash can be obtained. The organic heavy liquid was effectively recovered by vaporization, condensation, and absorption methods. Less than 5 parts per million of heavy liquid vapors were released to the atmosphere. This loss represents only 0.02 pound of heavy liquid per ton of ore treated.

Jan 1, 1973

By Robert A. Harrow

This report documents the results of the development and installation of an illumination system for an underground coal mine Shortwall Mining Section. Also presented are the techniques used for the above ground test and evaluation of the lighting system prior to installation underground which resulted in the issuance of a Statement of Test and Evaluation (STE) from the Mine Safety and Health Administration, Technical Support, Beckley, West Virginia.

Jan 1, 1979

Electrical trailing cable used to power coal mining machinery is frequently damaged in usage because of tensile strain or crushing effect of mining machines running over the cable. One of the repair problems is finding the exact location of a short or open in this cable so it may be spliced or otherwise repaired. The U.S. Bureau of Mines and FMC corporation signed Contract No. H0 122011 in August, 1971, to develop instrumentation for finding faults in coal mine trailing cable. This report describes performance of several existing instruments as trailing cable fault locators and also construction details and performance records of several cable fault location instruments that FMC designed, built and tested as part of this project.

Jan 1, 1973

By O. H. Metzger

This is one of a series of papers being published by the Bureau of Mines on mining areas and districts in the Western states. It describes mining and milling practices in the vicinity of Wickenburg in Maricopa and Yavapai Counties, Ariz. ACKNOWLEDGMENTS The author acknowledges the aid and cooperation of the operators of the mines visited. Reports of geologists and engineers who previously visited the area were drawn upon freely. Individual acknowledgments are made in the text.

Jan 1, 1938

By J. R. Cobble

As part of the Federal Bureau of Mines project to develop new or improved materials for metallurgical furnace applications, the Tuscaloosa (Ala.) Research Center has conducted research to develop a reproducible laboratory test for evaluating the resistance of refractories to molten slags. Tests were conducted with a slag representative of slag used to produce mineral wool. A rotating cylindrical furnace was lined with the brick being tested, and it was operated at temperatures up to 1,660° C for periods ranging from 8 to 32 hours. The effects of such variables as slag temperature, rotational velocity, charge rate, and contact time on refractory erosion were determined. The research demonstrated the reproducibility of the test procedure developed.

Jan 1, 1980

By J. A. Kost

The objectives of this contract were to determine the amount, size, and deposition of float coal dust (74 x 10 microns) generated during the mining and transporting of coal in underground U.S. mining operations. Rock dust distributed by trickle dusters was also sampled. In addition to four belt-transfer points, two continuous and two conventional mining sections were sampled at five mines located in Pennsylvania, West Virginia, Kentucky, and Illinois. Float-dust samples were collected on deposition pans; total airborne dust was collected with MSA Model C personal samplers equipped with Unico filter casettes; Andersen cascade impactors provided relative size distributions of the samples. Production, airflow, and water flow were monitored to examine their effect on dust levels.

Jan 1, 1981

By R. L. Marek

The number of persons fatally injured in the California petroleum industry in 1931 was 30, a decrease of 20 fatalities or 40 per cent from the number killed in 1930. As a result of the decrease in the number of fatalities for 1931, the fatality curve of tie California petroleum industry reached its lowest point in nine years. Although reductions in personnel--which permitted the retention of a select and experienced class of workmen, decreased active field-development work, and curtailed production--undoubtedly have had a marked effect on reducing the number of fatalities in 1931, the decrease also has resulted from continued accident-prevention efforts. Statistics show that a direct relationship exists between development activity and the number of men accidentally killed in the drilling and producing division of the California petroleum industry. For example, when the average number of drilling wells in 1930 was 29 per cent less than in 1929, the number of men accidentally killed at drilling wells dropped 48 per cent; and when the average number of drilling wells in 1931 decreased 52 per cent from 1930, the number of fatalities at drilling wells decreased 58 per cent. The relationship between field-development work and fatality frequency is significant because each year at least 50 per cent of all the fatalities in the California petroleum industry occur in the drilling and producing division. This relationship should serve to guide the accident-prevention efforts of the industry, especially in the drilling and producing division, toward checking an increase in fatal accidents when development activity again takes an upward trend.

Jan 1, 1932

By Richard F. Hewlett

Engineers at the Bureau of Mines Denver Mining Research Center have been a research program investigating the theory and application of mine sampling. Part of this program is an investigation of the efficiency of sampling methods that involves development of sampling-method theory through simulating ore-deposit samples and assays, using - electronic digital computer. Theoretical developments are checked against actual ore-deposit sampling, assay, and production data by the commonly used polygonal and triangular methods of computing grade and tonnage of ore reserves. To speed the computing procedures, a program has been developed utilizing a medium-size digital computer for computing ore reserves by the polygonal method. This program calculates nine prismoids per minute at a total cost of $0.21 per prismoid. The complete program, written for an augmented IBM 650 computer, is described in detail; it can be used without change for computing ore reserves for a low-grade deposit. Modifications necessary to convert the program to compute ore reserves for virtually any other type of deposit or grouping of ore horizons also are given; however, the program is limited to using only vertical drill-hole data.

Jan 1, 1962

By G. Schuman

Variations in pyrite reactivity are known to exist within samples collected from different areas. Using samples collected from acid and non-acid sites, the relationship between the factors affecting pyrite oxidation and observed variations in pyrite reactivity was studied. Heavy liquid separations were used to extract the pyrite from nine pulverized rock, coal, and coal refuse samples. Simulated weathering tests were used to determine the degree of reactivity of the extracted pyritic material. Representative portions of each pyritic sample were analyzed for whole rock composition (including pyritic sulfur and neutralization potential), for elemental composition, and by x-ray diffractometry. The samples were also examined with reflected light microscopy to ascertain pyrite morphology distributions. Tests for the presence of iron-oxidizing bacteria were all negative indicating the leaching tests were conducted under abiotic conditions. The results of the simulated weathering tests permitted the partitioning of the samples into two groups based on positive or negative neutralization potential (NP) values. Determinations were then made to evaluate the degree to which a variety of factors, including temperature, partial pressure of oxygen and water, and crystallography affected pyrite reactivity. Multiple regression analyses showed no statistically significant relationship between degree of reactivity and elemental composition. However, for samples with negative NPs, a simple regression analysis showed a strong linear relationship to exist between the reactivity of the pyrite and the proportion of "unstable" pyrite (framboidal + mossy pitted) found in each extracted pyrite sample. Samples of pyrite with positive NPs, although producing acidity, did so in at least one order of magnitude less than the NP deficient samples, indicating the important role that NP plays in controlling pyrite reactivity. A simple linear regression between cumulative sulfate production and NP for the three samples with positive NPs had a correlation coefficient of 0.99. For the nine samples grouped together, a linear regression model between cumulative sulfate production and NP (both negative and positive) was established between log of sulfate and NP.

Jan 1, 1991

By E. D. Gardner

This is one of a series of papers written for the consideration of operators of small gold and silver mines in the West. The paper discusses smelting schedules, general smelting practices that have a bearing on rates, and the reasons for penalties or credits for certain constituents of ores. Crude gold and silver ores generally are shipped to smelters only when milling facilities are not available; however, high tailing losses in milling a high-grade or refractory ore or low smelting rates because of the fluxing value of an are may make direct smelting more economical.

Jan 1, 1936

By John C. Machisak

This publication, for the calendar year 1959, contains statistical data on injuries and employment pertinent to metal mines, ore-dressing plants, and primary nonferrous smelters, refineries, and reduction plants. The Bureau of Mines is authorized to request data on injuries and employment in the metal-mining industry, and the information, voluntarily submitted by the operators, contributes immeasurably to the promotion of safety in the metal-mining industry. Every effort has been made to make the annual canvass as complete as possible. The data presented are classified according to the hind of ore mined and includes information on copper, iron, lead-zinc, gold-silver lode, placer, uranium- vanadium, and miscellaneous metals. A breakdown of miscellaneous metals by commodity is shown in tables 17 and 18.

Jan 1, 1963