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By John A. Johnson

For the purpose of comparing the amounts of dust produced by various mining operations, samples of atmospheric dust were collected during a complete cycle of drilling, blasting and mucking at or near the face of the Bureau's Mount Weather testing adit while the efficiency of several types of stemming in metal-mine blasting was being investigated. ACKNOWLEDGMENTS All gas samples were analyzed in the laboratory of the Bureau of Mines Gas Section at Pittsburgh, Pa.

Jan 1, 1939

By Andrew M. Leszcykowski

In 1985, at the request of the Bureau of Land Management, personnel from the U.S. Bureau of Mines examined 18,700 acres of the 24,922-acre Eighteen Mile Wilderness Study Area to evaluate mineral resources. This study area is in east-central Idaho in Lemhi County, approximately 20 miles southeast of Leadore. The study area is underlain by Paleozoic marine sedimentary rock and Ordovician granitic rock. The sedimentary rock is primarily limestone and dolomite with a minor amount of siltstone. The Nicholia mining district borders the southern boundary of the study area. However, none of the district's mineral-bearing structures appear to trend into the study area. Just outside the northwestern part of the study area, on Clear Creek, is the E. J. Wilson and Sons? open-pit gypsum mine that operated until about 1977. About 120,000 tons of gypsum were produced from the mine for the cement plant at Inkom, ID, and for use as soil conditioner. Two theories for the origin of gypsum deposits are a hydrothermal source and a stratabound occurrence. Hydrothermal deposition is favored for this deposit. Occurrences of gypsum may exist in the study area. However, known reserves are adequate to meet needs for at least 800 years. There are no known mines, claims, or leases in the study area. INTRODUCTION This report describes the USBM (U.S. Bureau of Mines) portion of a cooperative study with the USGS (U.S. Geological Survey) to evaluate mineral resources and potential of part of the Eighteen Mile WSA (Wilderness Study Area) 1/ at the request of the Bureau of Land Management (BLM). The USBM examines and evaluates individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will be used to help determine the suitability of the study area for inclusion into the National Wilderness Preservation System. The immediate goal of this and other USBM mineral surveys is to provide data for the President, Congress, government agencies, and the public for land-use decisions. The long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986

By W. J. Boone

The Bureau of Mines has programmed for publication a series of Reports of Investigations of studies it has undertaken on low-temperature phase equilibria of several helium-bearing natural gases. This report is the second of a series of papers of the same general title; it is anticipated that additional reports of this series will be published. The advent of a helium conservation program and the prospect of production of helium by private industry, make it especially desirable to publish these data. This report describes phase equilibria related to a natural gas that is processed for helium at the Bureau's Exell Helium Plant (located about 35 miles north of Amarillo, Tex.). Carbon dioxide and water in the gas were removed before making the study; hence the data obtained are representative of the gas stream immediately after similar preliminary treatment in the plant process. Phase equilibrium data were obtained for conditions from -50° to -275° F. and from 100 to 500 p.s.i.a. Analyses of samples were made as follows: For a given run at a selected temperature and pressure, samples of the vapor and liquid phases were analyzed by mass spectrometer, and an additional sample of the liquid phase was analyzed for helium by means of special apparatus (7). 4

Jan 1, 1962

By Edwin M. Thomasson

HELIUM SHIPMENTS in 1964 exceeded the volume shipped during the previous year for the 15th successive time. Shipments from Bureau of Mines helium plants were 667.4 million cubic feet,2 about 6 percent more than in 1963. Production at Bureau of Mines plants totaled 784.5 million cubic feet. An additional 3,193.1 million cubic feet, which was produced by private companies participating in the helium conservation program, was purchased by the Bureau and stored underground for future use. The Bureau of Mines continued to sell helium at $35 a thousand cubic feet, the price established in 1961. Substantial railway freight rate reductions for tank car shipments of helium went into effect during the year, resulting in a lower delivered price for helium. As the Nation moved ahead in the space age, it became increasingly apparent that helium would continue to play an essential role in research, in technology, in defense, and in industry.

Jan 1, 1965

By Stephen R. Iverson

Mineral deposits examined in and near the Raywood Flats RARE II area have low potential for development. The Mill Creek Mine (fig. 1), has produced about 14,000 tons (13,000 t) of marble, and another 5.5 million tons (5.0 million t) of marginal marble reserves suitable for lime, chemicals, and cement production are estimated to remain at this deposit. However, nearly all the marble is outside the study area. The deposit is marginal because alternate sources of marble are closer to markets. A tungsten occurrence in the marble is too small and low grade to be considered a resource. Ten tons (9.1 t) of uranium- and thorium-bearing material have been mined from a pegmatite dike at the St. Patrick Mine. However, this occurrence also is too small and low grade to be considered a resource. More than 400 lode and placer claims have been located in or near the study area. There are no current claims or mineral, oil and gas or geothermal leases.

Jan 1, 1983

By J. F. Neill, O&apos

The manganiferous schists occurring in the vicinity of Kings Mountain, North and South Carolina, suggest significant tonnages of potential submarginal ores. Although some reconnaissance work in connection with these deposits has been reported, no recent information has been published. Evaluation of the schists as a possible domestic manganese resource has not always adequately considered the fact that the manganese content occurs quantitatively both as oxide and as the silicate, spessartite. The Bureau of Mines investigation herein reported includes preliminary studies to indicate the extent of manganese oxide mineralization and to deter-mine the amenability of the material to sulfur dioxide leaching. The field reconnaissance studies suggest a resource containing in one area an average of 6.4 percent manganese as oxide. The procurement of depth information was beyond the scope of the investigation.

Jan 1, 1962

By John J. Sammarco

The U.S. Bureau of Mines has developed a regulated, intrinsically safe, rechargeable power supply for portable electronic equipment for underground use. The regulated output is ideal for microprocessor power requirements and is suited for operation in hazardous environments. Two rechargeable, sealed batteries are contained within the power supply. Provisions are made to use an external source of power if these batteries fail. Provisions are also made to charge these internal batteries when needed. The circuit is composed of three main circuits: the main regulator circuit, the input protection circuit, and the output protection circuit. The main regulator circuit provides remote voltage sensing, current sensing, fault monitoring, and internal thermal protection. The input protection circuit checks for excessive input current and low battery conditions. The output protection circuit contains two overvoltage detection devices. Schematics, a parts list, and a calibration procedure are provided in this report to enable readers to fabricate the power supply.

Jan 1, 1989

By J. C. Franklin

A data-acquisition system was designed by the Bureau of Mines to monitor five detectors with radon continuously flowing through each. These detectors could be monitored up to 12 times an hour, but were only monitored according to a preset time, thus allowing radon to be monitored continuously in a uranium mine. The counter can be set to monitor each detector for any period of time up to 16.5 minutes. This allows very low concentrations to be monitored longer to reduce statistical error. There would be no upper limit in radon concentration that could be monitored, but there would be a lower limit of 50 picocuries per liter (pCi/l). Each detector was cylibrated in the laboratory by the Lucas flask method. Multiple samples were taken at two different concentrations, and the correction factor for each detector was determined by a least squares fit of the data. To verify the calibrations, a series of measurements at several concentrations were made against a constant source. Our agreement at low radon concentrations (300 pCi/i) with the two-filter method as within 3 percent; thus, the total error would be this difference plus the two-filter error. At high concentrations the coefficient of variation ranged between 2.1 and 9.8 percent for the five different detector units.

Jan 1, 1976

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 Ferron A. Olson

Natural bornite (Cu5FeS4) leached in ferric chloride or in sulfuric or hydrochloric acid solutions with oxygen showed several differences. In ferric chloride 80 of the copper was leached in two stages. The first (30 copper removal) requiring one minute was controlled by mixed kinetics (liquid ferric ion diffusion and chemical surface reaction). The second was controlled by formation of a surface sulfur layer and then diffusion through the sulfur. With oxygen in sulfuric acid reaction was slow and only the first stage was studied. Copper removal had an induction period. The bornite structure disappeared at 12% copper removal (also found with ferric chloride) and covellite formed on the surface with a species inside the particles having an x-ray structure similar to CuFeS2 but with composition Cu3FeS4 (also with ferric chloride). Copper removal was controlled by iron dissolution. Surface iron vacancies filled with Cu+ to give CuS while interior copper dissolution produced Cu3FeS4. Preliminary results with oxygen and hydrochloric acid showed 80% copper removal and sulfur as end products (similar to ferric chloride).

Jan 1, 1982

By Glenn Adkins

This report characterizes pivoting joints in the structures of mining machinery and how the wear on the various components, i.e., pins, lugs, yokes and bushings, may affect the safety of mine personnel where these components are allowed to wear excessively before repair or replacement.

Jan 1, 1979

By A. J. Farstad

Recent advances in microcomputer technology have opened the way for systems which can track the location of underground mining personnel from the surface. A computerized system has been designed which is capable of not only tracking the location of the miner but also of monitoring underground parameters, communicating between work stations and sounding alarms when underground conditions are judged to be unsafe. For the system described herein, the locations of the underground personnel are detected by a network of underground terminals which routinely emit RF pulses to interrogate miniature transponders worn by the miners. Each transponder is uniquely programmed to delay its response in such a way that the RF terminal can identify the individual transponders by the time slots in which the responding pulses are received. The underground terminals are then interrogated by the host computer on the surface which keeps a running account on underground mine conditions and personnel. The underground portion of the system is designed to operate even during mine emergencies, deriving its power from rechargeable battery supplies which are float charged during normal operation. Nine mines were visited on this program and the industry reaction to the system was generally favorable. By slanting the system design for daily use in the mine, the chance of its acceptance by the industry is enhanced. Furthermore its likelihood of being operational in the event of an emergency is significantly increased.

Jan 1, 1981

By N. Barton

Large scale tests were conducted on quartzitic gravel and crushed sand-stone to investigate pertinent geotechnical properties for backfill support of egress shafts. Such shafts are envisaged for rapid launching of deep-based missiles. The backfill support is designed to resist shaft closure under dynamic loading, and must also drain rapidly to a lower catch chamber to allow launching. Large scale tilt shear tests were performed to measure the internal shear strength of the two backfill materials. Shaft filling and emptying tests were conducted in a 12 ft deep, 3 ft diameter model section of shaft drilled in sandstone. One half of the model was smooth bored, the other half rough-surfaced to represent drill and blast surfaces. Vertical and horizontal pressure cells indicated that stress only built-up during the first 1 to 1 ½ diameters of filling, due to the high-sidewall friction of 38° for the rough shaft and 31° for the smooth shaft. Interface sliding tests were performed to confirm these figures. Static and dynamic deformation tests were also per-formed, and indicated moduli as high as 56,000 psi, which will give excellent shaft support. Both the shaft support characteristics and the ease of emptying of gravel look particularly promising.

Jan 1, 1983

By C. B. Manula

This report is volume 5 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report describes the Subsidence subsystem of the Master Design Simulator. This subsystem uses the finite element method to simulate ground movement caused by an advancing mining face in an underground coal mine. The model is structured around the concept that the ground mass is a layered media of different thicknesses and material properties. Gob areas are considered to be unfilled with broken rock at the beginning of mining. After mining starts, the gob areas are filled with broken material which provides resistance to the lowering of the overlying strata. The model is tied to the Geology and Reserves subsystem, but it can also operate as a free standing routine. A case study is presented illustrating the application of the model. A detailed user's manual, including a program listing, is included in the appendices.

Jan 1, 1974

The following report summarizes the results of engineering feasibility studies whose purpose was to assess the probable efficiency, reliability, safety and cost of a number of possible methods for removal of radon gas from the ambient air in underground mines. Fourteen candidate techniques were evaluated. Seven of these were based on specific individual principles, and seven were based on combinations of these principles. The individual principles were as follows: 1. Activated charcoal 2. Organic fluids 3. Semipermeable membranes 4. Molecular sieves 4. Cryogenics 6. Chemical reaction 7. Centrifuge The combinations were: 8. Cryogenics and activated charcoal 9. Cryogenics and molecular sieves 10. Cryogenics and chemical reactions 11. Membrane filters and organic fluids 12. Membrane filters, cryogenics and activated charcoal 13. Membrane filters and chemical reactions 14. Silica and an Organic Fluid

Jan 1, 1975

By W. H. Goghill

Numerous investigators have studied grinding. Each has contributed his bit to a literature that is difficult to correlate. Too many of the results have been transformed into curves with so many "inflection points" and "counterflexures" that they obscure the issue. Some of the investigators have neglected the very essence of the problem, namely the power and the amount of material to which a known amount of work was applied. The purpose of this paper is to show the ease with which results can be interpreted when these quantities are duly recognized. Some grinding tests will be given for illustration. Grinding studies are of two kinds: (1) Study of the character of the ore and (2) study of the performance of the machines. Several ores may be crushed by a given machine, or several machines may be used on a given ore. The illustrations given in this report cover both objectives.

Jan 1, 1934

By John J. Sammarco

The U.S. Bureau of Mines seeks to increase safety and efficiency in U.S. coal mines. One approach is to develop technology for automation of a continuous mining machine. Realization of an autonomous mining machine requires development of subsystems for machine intelligence, navigation-positioning, and computer control. This report focuses on investigation of one subsystem, an onboard heading system, which would be responsible for determining and controlling machine heading. The onboard heading system investigated is a multisensor system to determine machine heading, pitch, and roll. A directional gyroscope provides heading (yaw), fluxgate sensors provide a compass heading, and gravity-referenced clinometers give machine pitch and roll. The system utilizes a dedicated microcontroller networked to an external system of computers. Tram commands, supplied to the network from external computers, are executed by the onboard system. Sensor feedback is employed for closed-loop control of machine heading by controlling pivots and turns. The report discusses operating limitations and error sources of system sensors and presents test results of closed-loop control of machine heading. Results of tests with a mining machine are used to exhibit various sensor shortcomings and to evaluate control of pivots and turns.

Jan 1, 1990

By James R. Aggson

This Bureau of Mines report describes floor heave ground control problems that have been encountered in a new underground coal mine in West Virginia. Previous experience in the coal seam, the results of physical property investigations, and in situ rock stress determinations are discussed. The apparent cause of the ground control problems is the existence of a high, biaxial, horizontal stress field coupled with a floor member that has time-dependent deformation characteristics, A theoretical analysis of the failure process is developed. The analysis is assisted by finite element techniques. Mine design recommendations based on this analysis are presented.

Jan 1, 1978

By B. W. Haynes

This Bureau of Mines report describes the laboratory processing of manganese nodules and the results of tailings characterization obtained during the cooperative program with the Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and the Bureau. Five technically feasible first-generation nodule processing methods were operated at bench scale to generate sufficient tailings and slags for physical and chemical analyses. A description is given for the laboratory operation of the individual unit operations of each process. The laboratory-generated tailings and slags were tested for physical properties, mineral content, elemental and ion content, and leachability for all five processes. The results of leachate testing using the Environmental Protection Agency extraction procedure (EP) toxicity test, the American Society for Testing and Materials shake extraction test, and the EPA-U.S. Army Corps of Engineers seawater elutriant test showed very low to negligible leaching of metals from the tailings and slags. Results of the EP toxicity test demonstrated that the wastes are nonhazardous as defined in the Resource Conservation and Recovery Act (Public Law 94-580).

Jan 1, 1985

By R. J. Matetic

The Bureau of Mines, as part of a program to improve mine planning and development, is currently investigating the effects of pillar load transfer, which can impact mining operations wi.thin a multiple-seam configuration. At two mine sites where such ground interactions were present, the Bureau performed a complete geological analysis and installed and monitored instrumentation to gather pertinent data on rock mechanics. Overburden depth varied dramatically in the vicinity of the study area and reached a maximum at the study site; innerburden thick-ness was less than a pillar width (40 to 4S ft); heaving was experienced in both mines where sandstone and/or shale floor units were observed; overlays of the mine layouts show pillars were not totally superpositioned; a maximum of S in of roof to floor convergence was measured; and pressure readings indicated pillar core loading only and increased to a maximum of 7,000 psig over instrument setting pressure.

Jan 1, 1987