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By Robert W. Geehan

"INTRODUCTION A preliminary examination of the Argentena mine was made in 'January 1945 by an engineer of the Bureau, who recommended investigation by diamond drilling. The Bureau conducted a core-drilling project at the mine from April 30 to August 4, 1946. Claims investigated are in sec. 33, T. 24 S., R. 58 E., Mount Diablo base and meridian, in southern Clark County, Nev., about 2.2 miles west of Goodsprings.The Argentena mine has been an intermittent producer of zinc-lead-silver ore since 1926. During the war years, ore was shipped to the Government stock pile at Jean, Nev., and to the International Smelting F. Refining Co.'s smelter at Salt Lake City, Utah. The mine has been shut down at intervals because of lack of a market for mixed oxidized zinc-lead ore.The 12 holes drilled by the Bureau totaled 1902 feet. The program was designed to test for faulted portions of the ore bodies know in the mine and to test favorable areas for similar ore bodies. As a result of this program, one faulted segment of the ore body was found, and it was established that no one was present in a second fault block. Similar blocks remain unexplored in the vicinity of the mine. Two holes drilled in favorable areas several hundred feet from the mine failed to discover new ore bodies."

Jul 1, 1947

By Bruce Maxwell

The deformation modulus of coal mine pillars theoretically can be reduced by drilling holes in advance of the mining face. This reduction of modulus along the edge of the pillar has the effect of decreasing the stress concentration in the roof; control of roof caving is thereby predicted. Initial field work indicated that a high horizontal stress field existed at the field test site: Subsequent field work was undertaken to confirm the high horizontal stress field and to attempt to relieve the horizontal stress in the immediate roof. A method of softening pillars in conjunction with normal mining activity was developed. Instruments to measure horizontal roof strain, roof parting, roof tilt at the rib, and changes in vertical and horizontal stress in the roof and in the coal were used. These instruments were installed in both softened and unsoftened entries and in locations to indicate the effect of vertical slots in the roof. Significant stress reduction due to pillar softening was indicated, but the effect of this reduction on roof stability was not established. The vertical roof slots relieved the horizontal stress in the immediate roof very effectively, and observations of roof conditions indicated that the slots definitely improved roof stability.

Jan 1, 1977

By J. C. Gerdeen

SAP-S information on the following element types are included in this appendix: Type 1. Three-Dimensional Truss and Bolt Element Type 4. Two-Dimensional Finite Elements Type 8. Variable-Number-Nodes Thick Shell and Three-Dimensional Elements Type 9. Two-Dimensional Joint Element (to be used with Type 4 elements) Type 10. Three-Dimensional Joint Element (to be used with Type 8 elements) Additional SAP4 elements, Types 2, 3, 5, 6, 7 and 12, are also contained in SAP-S and information on these elements is readily available in any SAP4 user's manual. These elements are as follows: Type 2. Three-Dimensional Beam Elements Type 3. Plane- Stress Membrane I-r .n Elements Type 5. Three-Dimensional Solid Elements (8 Node: Brick) Type 6. Plate and Shell Elements (Quadrilateral) Type 7. Boundary Elements Type 12. Three-Dimensional Straight or Curved Pipe Elements

Jan 1, 1976

By Thomas J. Peters

Tungsten, silver, lead, zinc, and placer gold occur in the Cucamonga B RARE II area (no. B5174). A strata-bound, scheelite-bearing zone at the Blue Diamond prospect (fig. 1, no. 1) contains an estimated 16,000 tons (15,000 t) of identified, subeconomic resources averaging 0.16 percent tungsten trioxide (W03). There is a high potential for discovering additional tungsten resources at this property. The California-Hercules prospect (fig. 1, no. 5) ha; a mineral occurrence which contains an estimated 1,000 tons (900 t) of tactite averaging 1.3 oz silver per ton (45 g/t), 0.75 percent lead, and 0.72 percent zinc. Another occurrence, at the Blew Jordam Prospect (fig. 1, no. 4) has an estimated 100 tons (90 t) of tactite averaging 10 oz silver per ton (340 ,/t), 3.75 percent zinc, and 2.3 percent lead. There is a moderate potential for discovering silver, lead, and zinc resources at these prospects, which are in metamorphic pendants. There are a few lode gold prospects in the area (fig. 1, nos. 3, 11, 14) are on geologic structures which parallel the San Andreas Fault, northeast of the area. These deposits are not well exposed and have been historically unproductive. Placer gold in area B occurs locally in the beds of intermittent tributaries to Lytle Creek (fig. 1, nos. 10, 12, 13) in concentrations as high as $1.17 per cu yd ($1.53/cu m, at a gold price of $450 per troy oz). The deposits have no significant volume, but could be utilized for recreational panning and suction dredging. In the Cucamonga C RARE II area (No. C5174) placer gold occurrences locally contain as much as $1.23 per cu yd ($1.61/cu m). However, gravel containing the gold appears to be limited to stream beds, and does not occur in sufficient quantity to constitute resources. Recreational panning and dredging also may occur in this area.

Jan 1, 1983

By John C. Gagliardi, Walter K. Utt

The U.S. Bureau of Mines, in cooperation with Carter Mining Co., conducted vibration tests of four off-road vehicle seats. The purpose of the tests was to determine which seat provided the best vibration attenuation under laboratory conditions. Laboratory tests were constructed to simulate the mining vibration environment within the limitations of the test equipment. The acceleration test levels and corresponding response of the seats were low compared to IS0 2631's fatigue-decreased-proficiency time limits. Two of the seats employed mechanical suspensions and two seats employed air suspensions. The seats were tested using a 22,241-N (5,000-lbf) electrodynamic shaker. Mechanical suspension seats were tested with various preload-to-mass ratios (PMR's) and cushion densities. Air suspension seats were tested with various air pressure levels and seat cushion densities. Air suspension seats provided good vibration attenuation if pressurized greater than 552 kPa (80 psi). Mechanical suspension seats' attenuation performance decreased if the PMR exceeded 9.8. Seat cushions of lower density provided less vibration damping.

Jan 1, 1993

By Gordon R. Sima, John L. Bennett, Roger L. King

Electric shocks are a serious problem in the mining environment. Because of extremely wide ranging use of electrically powered equipment in the mining industry, the hazard to personnel due to electrical shock and related injuries are not restricted to any single area but cover the entire spectrum of mining activity. Electrical accidents, resulting in personal injury, due to im- proper or complete lack of grounding of electrically operated mining machines, form a significant percentage of the overall electrical accident picture. The object of this paper is to describe methods of detection of unsafe electrical conditions with respect to the grounding of electrically operated mining equipment. It also includes a discussion of prototype instruments which effectively monitor the condition of the grounding safety devices currently in use on mining equipment and warn of dangerous conditions as soon as they appear. The paper is based on work accomplished under USBM Contract Number 50357115. The contract was initiated under the Pittsburgh Mining and Safety Research Center Program. It was administered under the technical direction of PM and SRC with Mr. Roger L. King as the Technical Project Officer. Mr. Daniel B. Dawkins was the Contract Administrator for the Bureau of Mines.

By Verne E. Hooker

Near-surface temperature measurements in two granite quarries show that diurnal temperature variations are significant to a depth of 1 or 2 feet, and annual temperature variations are significant to a depth of at least 25 feet. As a result, ground stress anomalies due to temperature exist near the surface, and their magnitude depends upon the time of day and the time of year. Rock stress and corresponding temperature measurements were made in one granite quarry over a rock temperature range of 33° to 81° F. Measured rock temperatures show good agreement with values predicted from one-dimensional heat flow theory. Calculated and measured stress-temperature coefficients for the two granites in this study are given. Thermally induced stress variations in near-surface rocks tested were as large as 1,690 psi from combined daily and seasonal temperature changes.

Jan 1, 1971

Table A-1. Number of underground coal mines and samples collected for underground occupations, 1988-92 [ ]

Jan 1, 1997

By Clarke E. Schuetze

This project had as its objective the experimental investigation of water capsule production utilizing the Southwest Research Institute's submerged nozzle encapsulation apparatus (U.S. Patent 3,389,194). Initial efforts on this project involved nozzle configuration and shell formulation optimization. The shell formulation developed on a prior program was modified during the course of the project to obtain the best balance of capsule breakage resistance and water retention. Subsequent effort centered on determining operating conditions which would produce the best quality capsules for each candidate shell formulation as determined by laboratory tests. Some preliminary work was done to increase the production capacity of the encapsulation equipment. The program was extended with major emphasis concerned with scale-up studies of capsule production capacity and the treatment of problems associated with grouting cartridge fabrication. During the course of the program, water-containing capsules were produced which have good long-term water retention, block resistance and adequate strength. Using a single-nozzle design, a production capacity of 15.9kg (35 pounds) per hour was demonstrated to give acceptable capsules based on initial results.

Jan 1, 1978

By Walter D. Holland

This instructors guide is intended for use in a course which teaches metal and non-metal mine inspectors to perform surveys for inhalation contaminants in above ground metal and nonmetal mine work areas. The handbook entitled "Handbook for Surveys of Inhalation Contaminants in Above Ground Metal and Nonmetal Mining and Processing Work Areas? is used as a manual during the course. The manual contains a survey check list, rules for determining if sampling is required, a list of most frequently encountered contaminants, a list of candidate contaminants and their sampling conditions, and a description of control procedures and devices. There are several experiments in this guidebook which the trainees perform to acquaint them with the sampling systems.

Jan 1, 2011

By R. S. Olsen

Although aluminum is easily leached from calcined clay with boiling mineral acids, the presence of fines and slimes in the leached residue has hindered the application of acid leaching processes. A feed preparation method was, therefore, devised that provided a dense, smooth-surfaced, fine-grained clay. The important factors affecting feed quality were determined to be (1) crushing the raw clay to the size desired for the leaching process, (2) moistening the crushed clay with a fine mist of water while tumbling on a rotating disk, (3) drying the misted clay, and (4) calcining the dried clay at 750° C in a fluidized bed. Clay treated by this method was leached with HCI, and its residue was washed by water displacement in 4-ft-deep beds. Bed permeabilities on the order of 47 darcys or 4.6 x 10-7 cm2 were obtained with the leached residues.

Jan 1, 1983

By Kenneth L. Whitehead

After many years of research, the occurrence of pneumoconiosis, black lung disease, among miners has been related to the mass of respirable coal dust to which mining personnel have been exposed. Congress passed Public Law No. 91-173 in 1969, which limited the dust concentration of respirable dust allowed in the mine working areas to 2.0 mg /M3 as of December 31, 1972. As a result of these restrictions, much work has been done in determining methods of either eliminating or suppressing respirable dust. The purpose of this project is to determine the state-of-the-art in continuous mining machine bit technology, particularly with regard to dust production.

Jan 1, 1973

By Jeffrey S. Walker

The purpose of this U.S. Bureau of Mines effort was to determine if ground movement caused by mining-induced subsidence is directly transferred to a structure and, if so, how that transfer takes place. Four concrete block walls with foundations were constructed and monitored over an active longwall panel. Three of the walls were located perpendicular to the direction of mining in zones where maximum inclination, maximum tension, and maximum curvature were predicted to occur. The fourth wall was constructed along the centerline of the panel, parallel to the direction of mining. All of the walls and the surrounding ground surface were instrumented with conventional survey monitoring points and extensometer stations to observe the vertical and horizontal movements. The fourth wall instrumentation also included continuously recording tiltmeters. The results of this investigation indicate that these simple structures respond to subsidence in a similar manner as the ground surface. This suggests that once the transfer mechanism is more fully defined, prediction models can be developed to accurately estimate the effect of mining on surface structures.

Jan 1, 1989

These proceedings consist of papers presented at three Bureau of Mines Technology Transfer Seminars on ergonomics in the mining industry. These seminars were held in December 1981, and covered topics relating to ergonomics and mining in the areas of the man-machine interface, and design of the work environment. This area of research is directed toward reducing accidents traditionally associated with human error.

Jan 1, 1981

By D. Bienstock

To develop a rugged catalyst capable of withstanding hydraulic attrition resulting from the oil-circulation process for synthesizing liquid fuels, use of an iron catalyst containing an active coating surrounding an inert solid core of metal was investigated. This massive-iron catalyst in the form of steel shot and lathe turnings was activated by partial oxidation with steam at 600° C, impregnated with alkali, and reduced with hydrogen at 450° 6. The massive-iron catalysts were resistant to oxidation and spalling, and a 6-month catalyst life was attained. Higher operating temperatures could be employed than with fused iron oxide catalysts, resulting in greater gasoline yields. Because the lathe turnings pack with void volumes of 70 to 90 percent, it has become possible to employ a fixed bed without the danger of cementation that occurs with fused iron oxides.

Jan 1, 1963

By G. R. Peterson

To determine the availability of aluminum from world bauxite resources, the Bureau of Mines investigated 139 bauxite deposits worldwide and evaluated the potential production of aluminum based on the demonstrated resources of bauxite ore from 91 mines and deposits in 22 market economy countries. The demonstrated resources of the bauxite mines and deposits included in this study represent an in situ resource of 20.2 billion metric tons of bauxite. Total identified bauxite resources in market economy countries amount to roughly 31.9 billion tons. Of the demonstrated resource, some 18.8 billion tons of bauxite considered minable provide a production potential of 3.6 billion tons of primary aluminum. Given the wide geographic distribution of bauxite deposits, stable supplies of bauxite for aluminum production seem assured well into the next century. However, a tight market situation could develop during the 1990's unless the real price of aluminum increases enough to stimulate massive new investments in production capacity, particularly in refining and smelting. This study indicates that a real price of at least $0.85 per pound (in January 1980 dollars) would be necessary to stimulate the required investments and provide a sufficient rate of return on invested capital.

Jan 1, 1983

The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment; including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that are recommended in this document, but all of the panic bars are characteristically of the ?fire door? type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they are required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in "Guidelines for the Design and Installation of Devices for Deenergization of Self -Propelled Electric Face Equipment/Automatic Emergency Brake s II by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel at the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By K. M. Connor, O&apos

Variations in overburden geology must be considered in applying subsidence prediction methodologies developed by the U.S. Bureau of Mines (USBM). To characterize rock mass overlying high-extraction coal mines, the USBM utilizes a computer spreadsheet program and modified Rock Mass Rating (RMR) system. The spreadsheet calculates an RMR based on a bed's engineering properties determined from core logs and laboratory tests. An in situ deformation modulus and a bending stiffness are computed for each bed. Stiffness-versus-depth plots identify groups of beds with similar stiffness. Large variations in stiffness between adjacent beds are considered significant horizontal discontinuities where slip is likely. Time domain reflectometry (TDR) is used to verify this hypothesis by measuring shear displacement along such discontinuities. A model of the overburden is built by assuming that a near-surface laminated beam exists above a transition zone in which large plastic slip occurs along horizontal discontinuities. Increasingly thicker groups of beds are modeled to determine the most probable beam thickness based on a comparison with measured deflection profiles. The inverse of maximum beam deflection is an index parameter known as "bridging potential," a single value that incorporates both overburden geology and mine geometry.

Jan 1, 2010

The Minerals Data Source Directory is a compilation of descriptive information on the availability, content, and location of minerals data in the Federal Government. It is intended to assist Government personnel and the general public in locating and acquiring minerals information. Included in the Directory are descriptions of data bases, publications, information systems, and information offices containing data pertaining to all aspects of mineral production, consumption, trade, and related information. These mineral data sources include the Federal agencies such as the Department of the Interior's Bureau of Mines and Geological Survey whose major mission is the collection and dissemination of mineral information. Also included are agencies such as the Departments of Agriculture, Commerce, Labor, State, and Treasury, and the Central Intelligence Agency, whose primary mission is the collection of data in non mineral subject areas, but in which the mineral industry is a component.

Jan 1, 1982

By J. B. Zadra

Tungsten metal, chemically equivalent to commercial grade, is produced by electrolysis of impure tungsten compounds or scheelite in an alkali, phosphate or borate electrolyte. A preliminary investigation of fused-bath electrolysis shows the effect of electrolyte composition, temperature, and current density on current efficiency, yield, crystal structure, and purity of product. Experiments show that tungsten can be electrowon from scheelite in a fused alkali, phosphate, or borate bath with similar results. Studies on electrolyte composition show that the addition of sodium chloride is essential to both electrolytes in treating scheelite. Although its main function is to react with or flux the CaO, it also increases the bath fluidity. Temperature studies revealed optimum ranges between 900° and 1,100° C.; 900° C. proved satisfactory for tungsten trioxide, and 950° to 1,050° C. for scheelite. Current efficiencies were satisfactory for all current densities ranging from 10 to 57 a./dm.2. Yields were 400 to 650 g./kw.-hr. over the same current-density range. Crystal size and purity of the product are functions of temperature, current density, and amount of impurities in the electrolyte. Deposited crystals vary in shape from spherical grains to clusters of dendritic hexagonal needles, and in size from smaller than 35 to 570 microns. The purity of the tungsten metal produced ranges from 99.7 to 99.94 percent.

Jan 1, 1959