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By A. D. McMahon

This survey is one of a series of Bureau of Mines publications designed to serve the needs of Government and industry for comprehensive information on mineral commodities and activities. Copper, a versatile metal, has been vital to all civilizations from prehistoric times to the present. Its essential value in antiquity and until the nineteenth century arose from its malleability and ease of working, its corrosion resistance and durability', its attractive colors in alloyed and unalloyed forms, and, of course, its availability. The principal uses were for tools, utensils, vessels, weapons, pipe, statuary and other objects of art, and for building and architectural pur£~ses where formability, permanence, and beaut)" were necessary qualities. Utilization of copper based on these physical and mechanical properties has grown tremendously for commercial, structural, mechanical, architectural, and art items; and its capacity for forming numerous alloys has led to a myriad of applications from miniature copper and brass eyelets to huge bronze battleship propellers. The early nineteenth century marks the epoch of the greatest use of copper, transmitting electrical energy. This particular property of copper is fundamental to the spectacular growth of the electrical industry and all associated industries relying on electricity for power, light, and heat. More than half of all copper produced is used for transmission of electricity. The copper industry has been able to expand along with the mounting demand because of the ever increasing discovery of resources in the world and advances in mining, metallurgical, and fabricating technologies. World production and consumption rose progressively from about 18,000 tons in 1800 to more than 4.5 million tons in 1960. The estimated world reserve of primary- copper has more than doubled since 1935, being 212 million tons in 1960. Ninety percent of this reserve is credited to eight countries-the United States, Canada, Chile, Peru, the Soviet Union, Poland, Northern Rhodesia, and the Republic of the Congo. The United States share is 32.5 million tons of copper in ore, averaging approximately 0.9 percent. Another reserve being accumulated in the industrial countries of the world is copper products now in use that will eventually be discarded as scrap and become available for recovering secondary copper. In the United States this resource of more than 30 million tons, provides about one-fourth of the annual supply.

Jan 1, 1965

By R. Pallini

The Franklin Research Center (FRO, a Division of The Franklin Institute was contracted by the U.S. Department of Energy to investigate the application of elastomeric materials for the purpose of smoothing loads on dragline thrust rollers. This report covers the design, fabrication, and demonstration of a portable- device for measuring roller circle track deviations and roller loadings. The results of this work are documented in this report. During December 1981, a field test group visited the Falkirk Mine, Underwood, North Dakota for the purpose of demonstrating the use of the designed and built device. The data collected indicates the practicality and usefulness of such a device for determining actual dragline roller circle roller loads, while the dragline is in service. The device was useful in determining roller load peaking that may be a contributing Factor in the premature failure of these thrust rollers. The device could be used for field evaluation of elastomeric cushioning materials used to eliminate these load peaks.

Jan 1, 1982

By P. R. Tisot

Structural response and/or deformation was determined for each of four different grade Green River oil shales (27.0-, 34.5-, 45.5-, and 63.5-gal/ton) as they were heated in an inert atmosphere, under constant compressive stress, from ambient to subretorting temperatures; that is, below those required for rapid pyrolysis of the organic matter. Small cores and small columns of confined fragments comprised the test specimens, which were heated, in a specially designed microunit, at a uniform rate either to 725° or to 825° F under three different stress levels, 80, 200, and 325 psi. Structural response of some cores was observed as they were heated in a stress-free environment. The obtained stress-strain-time-temperature relationships provide information regarding the oil shale's yield temperature, yield stress, rate of compressive strain, loss of mechanical strength, and nature of structural deformation. Effects of structural deformation on induced permeability in small columns of fragments are presented. Results indicate that underground retorting of Green River oil shale may be seriously impaired through loss of induced permeability brought about by structural deformation of rich oil shale under the influence of heat and compressive stress.

Jan 1, 1971

By Ben Aleck

The objective of this program was to adapt Space Shuttle technology on high-performance spherical pressure vessels to cylindrical pressure vessels. Specifically, a cylindrical aluminum liner overwrapped with fiberglass filaments and prestressed by yielding the liner under a sizing pressure was to be replaced by a higher strength-to-weight ratio steel liner overwrapped with a higher strength-to-weight ratio filament. The steel was cryoworked stainless steel and the new fiber was Kevlar 49. In addition, the heavyweight ends of the aluminum liner were to be replaced by thin-walled domes which required multiple helix angle wraps for their support, in place of the single kite-string wrap from pole to pole of the aluminum overwrapped design. The use of cold swaging of tube-ends to form bosses, demonstrated on subscale development efforts, had not been achieved full-scale when the contract was initiated. Difficulties arose with the full-scale demonstration which were not solvable at the time with the designs and equipment available. hence, an unanticipated development was the finally selected method of making the 4-in.-diameter stainless steel liner with a single boss and no welds in an 0.020-in.-thick wall, from an 0.050-in.-thick, 13-in.-diameter disk. The demonstration vessel failed by leakage during the prestressing step because embedded oxides had formed flaws in the boss region. Such flaws have been avoided by proper temperature control during hot spinning. Hence, a new design was developed which weighs half as much as its recently developed predecessor. Funds ran out before adequate testable hardware was produced.

Jan 1, 1983

This study of underground mine water inflow was initiated by the U. S. Bureau of Mines in March 1980. The objective of this study is to evaluate the hydrologic variables associated with surface water and ground water systems that affect the inflow of ground water into an underground mine. Data collection techniques are reviewed for their applicability for quantifying these hydrologic variables. Innovative techniques are also investigated. Existing analytical and numerical procedures for predicting underground mine water inflow are reviewed and evaluated. Over 300 computer models were reviewed for their applicability to modeling underground mine water inflow. The model UNSAT2 is utilized for modeling inflow to a shaft and tunnel or drift. This model and the techniques developed in this study are applied to two existing mines.

Jan 1, 1982

By J. B. Stott

The performance of an adiabatic calorimeter for measuring heats of oxidation of coal is assessed and suggestions made for its improvement and calibration. The use of magnetic analysers for measuring small oxygen deficiencies in air is described and three different methods of measuring the output for such a meter are characterised. The occurrence of spontaneous heating in an 800 tonne heap of Wyoming coal is briefly described. The major part of the report deals with the oxidation of Pittsburgh seam and Wyoming subbituminous coal and describes an experiment in which 1 tonne of Wyoming coal is stored in a 5 metre long insulated container whilst air was passed through. Temperature rises, rates of oxygen absorption and gas compositions of the air stream were measured. The report relates the results of these-experiments to a theory of spontaneous heating developed by Stott and Quan which stresses the importance of the moisture content of the coal and the relationship between the heat necessary to evaporate this water to the heat available from coal oxidation. The work was carried out over a five month period and the emphasis is on demonstrating the effects of moisture transfer and confirming the theory of Stott and Quan.

Jan 1, 1980

By A. G. Kim

Methane and other hydrocarbon gases, byproducts of coalification, are emitted from coal at widely varying rates and often present ventilation problems during mining. The air in some coal mines apparently contains no methane. To determine if coals from mines which bid no history of detectable gas emission contained adsorbed methane, samples of coal at the shaft bottom and at an active face were obtained and placed in sealed metal cylinders. The atmosphere around the coal was sampled and analysed by gas chromatography. Methane, ethane, ethylene, propane, propylene, and butane were found to have been desorbed from these coals. Hydrogen and helium were also detected. An estimate of the amount of residual gas per ton A coal indicated that coal samples from the active face generally contained more adsorbed gas than coal samples obtained from the shaft bottom, although in both instances the total amount of gas was relatively small.

Jan 1, 1973

By Ernest J. Conway

This report presents engineering drawings for six material handling devices for underground coal mines. The devices were designed under a U.S. Bureau of Mines program to reduce injuries from material handling during mine and equipment maintenance. The six devices are (1) scoop-mounted 1411: boom, (2) swing-arm boom, (3) heavy-component lift-transport, (4) mine mud cart, (5) container-workstation vehicle, and (6) timber car. Each device is described briefly, and recommendations are made concerning the design of new devices.

Jan 1, 1989

By Sheridan J. Rodgers

The quantity and behavior of gases in metal and nonmetal mines were monitored to provide background information on feasibility of incipient fire detection systems. Monitoring was conducted during working and nonworking periods at intake air, return air and working places. Gases generated during diesel operations and shot firing were of particular interest. Gases which were monitored were CU, C02, N0, N02 and S02: submicron particulate concentrations were monitored also. Commercially available instruments were used and included nondispersive infrared, electrochemical and chemiluminescent types. The ratios of the various gases generated during diesel operations and shot firing were similar to those expected from an incipient fire, with the exception of the C02/NOx ratio, which is sufficiently different to be considered for early fire warning. Samples taken near leaking bulkheads showed high C02 levels and low C0 levels, the reverse of anticipated behavior in coal mines.

Jan 1, 1976

By C. S. Tout

While investigating methods for determining the best temperatures for hot-working experimental stainless steels, the Bureau of Mines Albany Metallurgy Research Center developed a machine in which hot-twist tests could be made in a few minutes. This machine is similar to some used previously except that specimens are heated by induction instead of by radiation, and their temperature is measured by a calibrated radiation-detection unit instead of by a thermocouple. In. developing the technique for using the new machine, tests were made on specimens of medium-carbon steel, mild steel, and AISI (American Iron and Steel Institute) type 304 stainless steel. Tests also were made on as-cast specimens and preworked specimens of experimental AISI type 202, low austenitic stainless steel, and as-cast specimens of AISI type 301 experimental stainless steel. The optimum hot-working temperatures were determined for all types of steel tested. Also, data were gathered on the effects of test speed and temperature on torsional strength and the effect of twisting on tensile stress in the specimen.

Jan 1, 1962

By John P. Borovsky

A 3-year study was conducted to evaluate the problems and benefits of using vegetation to stabilize tailing from a potential Minnesota copper-nickel milling operation. The project consisted of three separate investigations: a waste characterization study, a greenhouse study and a field study. With few exceptions, the physical and chemical characteristics of the tai ling were found to lie within the range of properties of Minnesota soils. The tailing lacks organic matter; is deficient in nitrogen, phosphorus and potassium; and may contain elevated levels of soluble salts and heavy metals, particularly copper and nickel. Numerous grasses, forbs and woody plants will tolerate the tailing as a rooting medium. Peat incorporation and topsoil dressing provided few benefits to the revegetation process which were not provided by a fertilizer application. With fertilization, grass/legume production in the tailing was comparable to local agricultural yields. Concentration of heavy metals in grasses grown in the tailing were generally below suggested tolerance limits for plants and animal forage. Legumes tended to accumulate higher concentrations of copper and nickel, and metal uptake of most plants was positively correlated with rate of fertilization. Tailing drainage water contained elevated levels of heavy metals, and establishment of vegetation had little effect on the quantity and quality of tailing drainage water. However, topsoil dressing significantly increased drainage water volume when compared to unvegetated control plots. Copper-nickel tailing revegetation recommendations were developed.

Jan 1, 1983

By Philip C. Good

Red mud residue from Bayer process treatment of Jamaican bauxite was dewatered in batch and in continuous centrifuges. Solids content of the residue was increased from its original value of 20 to 25 percent to about 40 percent by centrifuging. Clear effluent amounting to approximately 40 percent of the slurry liquid was recovered containing dissolved alumina and soda values for potential recycle to the alumina plant" Addition of a chemical flocculant to the centrifuge increased capacity by about 35 percent. Manufacturer's estimate of large-scale equipment requirements, based on data collected in this investigation, was that a proposed installation for dewatering 16,000 tons per day of Jamaican red mud would require twenty-two 24-by 60-inch solid-bowl-type centrifuges. Cost analysis of a proposed installation, based on a Jamaican red mud tonnage of 16,000 per day, is included also.

Jan 1, 1968

By K. Hanna

This U.S. Bureau of Mines report describes a rock mechanics instrumentation program conducted in a shallow underground coal mine in central Illinois. This research program was designed to provide a basic understanding of the structural behavior of entry intersections. A wide variety of instruments and measurement techniques including hydraulic borehole pressure cells, multiple-point borehole extensometers, roof bolt compression pads, and overcoring were employed to monitor roof stresses, pillar loading, strata movement, floor heave, and bolt loading before, during, and after intersection development. A summary of intersection design theories, failure modes, and support techniques is included and instrumentation installation procedures and analysis methods are presented. The study identified two critical parameters that affect intersection stability: in situ horizontal stresses and geological discontinuities. Important design parameters for improving intersection stability are roof span and intersection geometry.

Jan 1, 1991

By Paul Hatmaker

Lime was a highly useful commodity thousands of years before the simple chemistry of its manufacturing process was known. The employment of lime for agriculture, building, and even certain essentially chemical purposes is so old that its origin is among the unrecorded details of man's first ventures into the manufacture and use of prepared substances. Lime is a most versatile material and consequently has come to be widely utilized in modern civilization. Immediately before the depression of the early 1930's the annual production of lime in the United States was more than 4 million tons, valued at 33 to 42 mil-million dollars. This output was sold to many industries, so many that mere enumeration becomes tedious.

Jan 1, 1934

By David A. Summers

The use of high pressure fluid cavitation is investigated as a means of breaking an ore into its constituent grains. This Cavitational Rock Dissagregation (CRD) is found to be possible and effective in breaking down galena ore, both in sandstone and dolomite host material. The technique did not work as well in comminuting and cleaning oil shale, because the cavitation drove the oil into emulsion with the water. The presence of dominant bedding in the rock also caused preferential breakage to these lines, rather than to the individual grain boundaries. This problem was also encountered in tests on igneous ore where weakness plants of the overall ore proved weaker than the boundaries of the individual grains. It was found that the prevailing expression of cavitation erosion dependence on pressure was not absolutely valid. In contrast it was found that CRD is much more sensitive to jet flow diameter, and when this was recognized it was found possible to erode rock with compressive strength of up to 350 MPa with operating jet pressures of 10 MPa.

Jan 1, 1982

By George T. Faust

The petrographer engaged in examining the products resulting from the beneficiation of ores and rock minerals is constantly required to develop new means and methods of assaying microscopically the results of such operations. From time to time investigators have published descriptions of apparatus that have aided in solving problems in processes f physical separation. Thus, in 191.9, Coghill and Bonardi 31 published a paper covering the application of the binocular microscope and camera lucida to the microscopic analysis of pulverized ores. Similar work has been published by Schneiderhohn 4/, Schwartz 5/, and Head and his associates6/, 7/, 8/. The present paper goes further and considers application of the polarizing comparison-microscope to problems directly concerned with mineral dressing where it is desirable to compare analogous products, and in addition it suggests new uses in various related fields. This work was conducted under the cooperative agreements of the Southern Experiment Station of the Federal Bureau of Mines and. the University of Alabama.

Jan 1, 1940

By Forrest T. Moyer

The safety record of the coal-mining industry in 1968 worsened appreciably .in fatality experience but was slightly better in nonfatal-injury experience. Work fatalities in 1968 totaled 311 and occurred at a frequency rate of 1.33 per million man-hours or worktime. The fatality total was 89 higher, and the rate of occurrence was 45 percent higher than the corresponding figures of 222 fatal injuries with a frequency rate of 0.92 in 1967. The worsened fatality record in 1968 resulted primarily from two major disasters (a single accident which results in the death of five men or more) which killed 87 men, nine in one and 78 in the second. The total of 9,639 nonfatal injuries was the lowest annual figure in complete records back to 1930. The frequency rate of 41.12 nonfatal injuries per million man-hours of worktime for 1968 was the second lowest annual rate of occurrence. The severity rate of all injuries, 10,513 days lost or charged per million man-hours, and the average severity, 248 days lost per injury, in 1968 were the worst annual data in the series started in 1944. Total worktime of 234.4 million man-hours and coal output of 553.3 million tons in 1968 were, respectively, 3 and 1 per- cent lower than in 1967.

Jan 1, 1972

To alleviate the hazard to personnel and danger to equipment caused by fires on large, mobile vehicles. The Approach: A system which automatically senses a fire at its early stage of development, warns the driver of the danger, and activates fire extinguishers in the zone of combustion, How It Works: The automatic fire protection system utilizes both thermal and optical sensors to detect the heat or light given off by a fire in the area of concern (Fig. 1). The system warns the driver of the hazard and then automatically extinguishes the fire with pressurized S-C class powder. The system can also be activated manually from the operator's cab or from ground level. Further, the automatic sequencing of the system can be manually overridden by the driver if he determines that the fire sensors have malfunctioned to cause a false alarm.

Jan 1, 1974

By W. R. Reed, J. A. Organiscak

Haul trucks have the potential to generate large amounts of respirable dust. This respirable dust has been shown to be a health hazard to personnel, especially if it has a high silica content. Lack of dust sampling data from haul trucks prompted the completion of a study to quantify respirable dust concentrations. These field studies were conducted measuring instantaneous respirable dust at stationary locations from passing haul trucks at a stone quarry and at a coal mine site. Fugitive dust levels from haul trucks were analyzed to characterize dust dispersion. This analysis indicates safe following distances for haul trucks and other heavy equipment to avoid overexposure of respirable dust from the lead haul truck.

By Daniel G. Di Canio

Reference information and user instructions for Version 3.0 of the Accident Cost Indicator Model (ACIM) software package are presented. ACIM estimates the tangible costs of occupational injuries, illnesses, and fatalities in the United States mining industry.

Jan 1, 1983