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By L. A. Stinnett

An investigation of hazardous surface openings of abandoned and inactive underground mines in the Black Hills area of South Dakota has revealed: (1) tracing legal ownership of mineral claims via county courthouses is confusing, complex, and oftentimes misleading, (2 ) in general, the selected mine openings in this investigation are to be considered relatively high in risks and hazard potential which poses a threat to the general public, (3) mine closure procedures and designs can generally be categorically implemented depending on the overall situation of the particular mine opening with subsequent unit costs' estimates, (4) few preventive state or federal legal measures exist to date concerning mine closures, and (5) liability damages relating to mine opening accidents usually involve expensive and complex common law cases.

Jan 1, 1979

By David B. Doan

This regional report covers 1993 mining and related activity in approximately 40 countries and territories of Canada, Latin America, and the Caribbean Basin. These countries of the Western Hemisphere, as with the United States, are endowed with a great variety of minerals, including metals, industrial minerals, and energy minerals. For most of these countries, such mineral production helps form foundations for their economies and earns export credits including hard currencies. Table 1 depicts an overall view of Latin America and Canada's production of its major mineral commodities in 1993; subsequent tables show the role of Latin America and Canada in world mineral production, trade, and import dependency on minerals from Latin America and Canada by the United States. Overall, the picture emerges of a rich mineral diversity throughout the hemisphere, attracting increasing interest and investment, and complementing the mineral resources of the United States.

Jan 1, 1995

By Linda C. Carrico

Those who manage the Nation's mineral resources rely upon a variety of organizations both public and private--to give them accurate mineral data, technical guidance, and expert advice. This directory provides a list of such organizations--a list that should prove a useful tool for those seeking mineral-related information and technical assistance. The directory lists Federal and State governmental agencies and national, regional, and State associations with activities in the mineral, metal, and material sectors of the economy. These organizations regulate mining, monitor mineral production, establish and enforce health and safety standards, identify and evaluate mineral resources, conduct scientific research, predict market trends, resolve environmental issues, and promote the interests of the mineral industry, its individual sectors, and its workers--to name a few of their functions. The listings in this directory--arranged by State--should help users who manage mineral resources identify agencies and organizations that can provide mineral-related information or technical assistance.

Jan 1, 1993

By J. Fletcher Smoak

Consumption of abrasive materials in the United States decreased 23% in value from that of 1981 to $262 million, of which 53% was manufactured abrasive, 39% was industrial diamond (natural and synthetic), and 8% was natural abrasive. Production of natural abrasives, excluding industrial diamond, appeared to be stable when compared with that of 1981. Production of tripoli, a porous siliceous rock, increased slightly after decreasing steadily over the three previous years. The production increase of garnet, an abundant iron-aluminum silicate, was attributed to increased output from one plant that had completed an expansion program in late

Jan 1, 1983

By M. E. Volin

The Ladd manganese deposits are in San Joaquin County, Calif., about 13 miles southwest of Tracy. The deposits are confined in two main areas of development, roughly about 1,700 feet apart horizontally, and known as the Ladd mine and Fabian mine, respectively. The deposits occur as interbedded lenses in the white cherts of the Franciscan formation. The ore minerals are bementite, rhodochrosite and psilomelane. As a part of the Bureau of Mines program of investigation and development of domestic mineral deposits, a development program was started. August 24, 1940, and completed on June 24, 1941. The Federal Geological Survey cooperated by mapping the geology and logging the drill cores. The program included road building, trenching, rehabilitating the mine workings, trenching underground excavation, sampling, and core drilling. The following pages mention the location, give a brief history, and note the physical features of +1-.1, district. Mine workings are sketched, the deposit is described and the plan of the project is noted. The work performed by the Bureau of Mines is explained in the concluding pages with a summary of the drill hole logs.

Jan 1, 1949

By Robert B. Worthington

This investigation was undertaken to develop a more efficient copper smelting practice that would help meet the increasingly stringent antipollution standards. Continuous smelting to copper and a 0.8-to 5-percent copper slag using pure oxygen has been demonstrated for several hours at a time in a unique double furnace, which was devised to overcome the heat losses inherent in a laboratory furnace. The use of pure oxygen to effect the smelting and conversion of copper sulfide concentrate in a single unit to produce blister copper and a very high S02 concentration provides a much reduced gas volume for more economical and thorough sulfur recovery. Although the process was successfully demonstrated for several hours at a time, extended test work using longer runs will be required to balance the system and to obtain test data for adequately demonstrating its technical feasibility.

Jan 1, 1973

As longwall shields are lowered in preparation for advance, dust from the canopy falls directly into the air stream with the potential of becoming entrained. Historical dust sampling data from the early 1980s shows that shield advance contributed an average of 12 percent to the airborne respirable dust levels found on longwalls in the United States. Data from the 1990s indicates that shield dust liberation had increased to an average of 23 percent. Increased longwall production levels over this time resulted in the need to move a larger number of shields during each shift, while an increase in air velocities on the face was also occurring. These factors combine to suggest that greater quantities of shield dust are being entrained into the face air. A series of controlled laboratory tests were conducted in a test stand simulating shield dust entrainment to evaluate changes in airborne respirable dust levels at different air velocities. Significant differences in respirable dust entrainment were observed. The test facility, test methodology, and dust sampling results will be reviewed and discussed

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

To mine uraniferous sand-stone in an economically feasible and environmentally compatible manner without placing men underground. Approach Uraniferous sand is remotely extracted through a single borehole by cutting Into the are around the borehole with a high pressure water Jet, and pumping the resulting slurry to the surface. How It Works A 16-inch-diameter borehole Is drilled from the surface down into the burled mineral deposit, and the mining tool Is installed. High pressure water Is released as a jet from a nozzle In the mining tool to erode the are, forming a slurry that flows to the bottom of the cavity. The slurry Is drawn Into Inlets located near the bottom of the drill string. See drawing. After being pumped to the surface, the slurry is weighed, metered, and checked for radioactivity. It is then deposited Into one of a pair of sumps. Water collecting in the sumps drains Into an adjoining pond for reuse. Thickened are In the sumps is removed and placed In piles.

Jan 1, 1978

By M. M. Wong

Beryllium possesses attractive properties for use in the nuclear and space fields. Since fused-salt electrorefining can be employed to produce this metal in high-purity form from low-grade or scrap metals, the Bureau of Mines investigated electrorefining of beryllium in electrolytes composed of a LiC1-KC1 eutectic mixture plus varying amounts of BeC12. Results showed a 99- percent or better reduction of oxygen and magnesium and a substantial reduction of other minor metallic impurities. Extremely pure beryllium metal was produced. Operating variables, including BeCl2 concentration in the bath (3.5 to 16.5 mole-percent), temperature of operation (450° to 550° C.), and cathode current density (45 to 770 a,/sq, ft.), were studied; their effects on the deposition of metal, working condition of the bath, and purity of the refined metal are discussed. The safety precautions used in handling beryllium in the laboratory are also described.

Jan 1, 1962

By William Porter

Hand scaling is a physically demanding job and is responsible for numerous overexertion injuries in mining. This experiment studied rib scaling from an elevated bucket to examine force generation capabilities and electromyographic responses to a prying subtask. Subjects exerted force using two bars (steel and fiberglass) at five target heights. Work height significantly affected peak prying force during scaling activities with highest force capacity at the lowest level (p = 0.0188). Bar type did not affect force generation (p = 0.7843): However, use of the fiberglass bar required significantly more muscle activity to achieve the same force (p < 0.05). It was concluded that miners should scale points on the rock face that are below their knees, and reposition the bucket as often as necessary to do so. Additional research is needed to fully understand the impact of bar type on the physical demands of an entire scaling task.

Jan 1, 2006

By Stephenson. E. L.

"INTRODUCTION In the spring of 1942 a series of magnetometer surveys on deposits of black sand underlying Pleistocene raised marine terraces along the coast of southwestern Oregon was nada by the Division of Geophysical Exploration of the Federal Bureau of Mines in cooperation with the Oregon Department of Geology and Mineral Industries. A few preliminary tests had been made in the same area in May 1940 and December 1941.The sands contain fine gold and metals of the platinum group, and, beginning in 1852, extensive, but spasmodic mining and exploration have been done for these precious metals. There are many old placer, mines and prospects, although for the most part the yield of the metals has been small. The sands also contain other minerals of potential value, including ilmenite, magnetite, garnet, zircon, and particularly chromite, and the wartime demand for domestic chromite resulted in extensive testing and development of the known deposits. The purpose of the magnetometer surveys was to determine the efficacy of, magnetic methods in tracing and outlining these known deposits and in prospecting for new ones. The field work was done between March 17 and May 29, 1942, by the author assisted by W.W. Paulsen of the Oregon Department of Geology and Mineral Industries."

Jun 1, 1945

By L. R. Herrmann

The most fundamental feature of fracture is that it involves separation. Such separation can arise by either separation of molecules, more or less along the line joining their centers (tension), or by d sliding separation roughly perpendicular to that line (shear). Theoretically, a perfect crystal could never be broken by the application of perfectly axial compressive stress (until some sub-molecular actions occur). In tension fields the calculated forces between molecules are extremely high. Consequently, calculations based on the forces known to exist in materials at the molecular and crystalline levels always lead to strengths which are two or three magnitudes higher than the strengths obtained in service or in the laboratory. It has been a major problem, therefore, to explain: (a) How fracture can occur in compressive stress states. (b) Why the observed strength of a material is always much lower than its calculated strength.

Jan 1, 2012

By Frank K. McIntosh

Bauxite was first discovered in Tennessee, at Chattanooga, in 1906, during the construction of&apos; the McCallie Street tunnel through Missionary Ridge. Several years later, bauxite was found in sinking a well on the Perry or Isabella Stewart property. These and other deposits furnished a substantial tonnage for the abrasive and chemical industries during the years 1906 to, 1920. The search for domestic sources of war material prompted by World War II brought the Tennessee bauxite deposits to the attention of the Bureau of Mines. During the summer of 1942, James S. Cullison and E. Godwin, geologists of the United states Geological Survey, made a survey of the bauxite deposits of the area. In August 1942, Harold B. Ewoldt, a Bureau of Mines engineer, accompanied by the Geological Survey party visited the area and a drilling program was prepared. Drilling was started in November 1942 and continued until March 1943. A total of 2,519.5 feet in 38 holes was drilled on three properties.

Jan 1, 1949

By Curtis H. Elder

In studies conducted by the Bureau of Mines, two test areas were hydraulically stimulated and exposed by mining: One in the Pittsburgh coalbed at the Vesta No. 5 mine, Washington County, Pa.; and one in the Illinois No. 6 coalbed at the Inland mine, Jefferson County, Ill. Induced fractures were contained totally within the coalbed with no adverse effect on the stability of associated rock strata. Induced fractures were vertical and were propagated normal to the direction of least residual tectonic stress. Gas production was increased fivefold to twentyfold by hydraulic stimulation.

Jan 1, 1977

By R. V. Ramani

This report is volume 10 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 Ventilation subsystem of the Master Design Simulator. The Ventilation subsystem has the capabilities to handle: (1) branches in parallel or series, (2) fans in parallel or series, (3) multiple fans, (4) methane, compressed air, or other injections into the system, (5) leakages and fixed quantities, and (6) calculations of absolute pressure at nodes. The program uses the Kirchoff&apos;s Junction and mesh laws, and the Hardy-Cross iterative technique to converge to the desired accuracy in solving fox the head quantity. A case study is included in the report illustrating the use of the model. The appendices of the report constitute a user&apos;s manual for the Ventilation subsystem, and include a program listing.

Jan 1, 1975

By T. J. Batchler, T. M. Barczak

The Code of Federal Regulations (CFR) requires that the transverse load capacity of stoppings be equal to or greater than traditionally accepted in mine controls, which for block stoppings is generally accepted as 39 psf as referenced in the preamble to the CFR standard. This measure is based on physical testing of a freestanding wall in accordance with ASTM E 72 specifications, where our past research has shown that the dominant parameter is the tensile strength of the sealant. A new protocol based on rigid arch loading of the structure is proposed to determine the true transverse load capacity of block stoppings. Arching is achieved by the restraint of the stopping against the mine roof and floor, whereby compressive forces are developed within the wall. A laboratory procedure using the NIOSH Mine Roof Simulator (MRS) to simulate rigid arching of block stoppings was developed and results verified through full-scale in-mine tests. The rigid arch tests have demonstrated transverse load capacities more than an order of magnitude higher than the ASTM E 72 evaluation method from which the 39-psf requirement is derived. More importantly, the rigid arch tests have shown that the load capability is dependent on the physical properties of the block and geometric properties of the wall and not the sealant.

By Thomas P. Mucho, David C. Oyler, Jim Pablic, Dennis R. Dolinar

A room and pillar coal operation in central Pennsylvania was experiencing roof cutters and long running roof falls caused by high horizontal stresses. The roof conditions created hazards for the miners, and caused several production panels to be abandoned prematurely. The mine requested assistance from the National Institute for Occupational Safety and Health (NIOSH) in applying the "advance and relieve" mining to reduce the affects of the horizontal stress during panel development. The "advance and relieve" plan that was developed called for removing a pillar on one side of the panel as it was being advanced, thus creating a cave. The caving then relieved a portion of the horizontal stress across the panel. Because the horizontal stress direction is key to the success of this method, stress mapping as well as mining experience was used to establish the direction of the horizontal stress. Subsequent field measurements provided an estimate of the stress magnitude. Three panels were mined using this technique, and good roof conditions were achieved in all these panels. Instrumentation was used to monitor the stress changes in the roof created by the cave. Stress relief of over 1,000 psi was measured 120 ft from the cave and to depths of 20 ft into the roof. The lateral extent of the stress relief zone across the panels appears to be about 400 to 500 ft. This case history has provided much insight into the practical application of the "advance and relieve" method discussed in this paper.

By William H. Pomroy

This report describes Bureau of Mines research that led to the design, prototype fabrication, and successful proof-of-concept testing of an improved stench fire-warning system for underground noncoal mines. Stench systems are the most widely used means of warning driers in underground noncoal mines of fires or other emergencies. A stench system alerts miners that an emergency condition exists by injecting an odorant into the mine air. Although stench warning systems have been used successfully for over 60 yr, present systems suffer several serious shortcomings, including odorant toxicity, unreliability of warnings, widely varying stench concentrations, and others. In 1980, the Bureau began a research program to upgrade the stench warning system. The resultant system overcomes the deficiencies of existing systems by substituting tetrahydrothiophene for the commonly used ethyl mercaptan stench odorant, and through the use of a specially designed stench injector. The improved injector reliably meters stench fluid into either ventilation-air or compressed-air streams at a precisely controlled rate. Prototype hardware has been fabricated and proof-of-concept tested under bath laboratory and in-mine conditions.

Jan 1, 1985

By C. E. Brechtel

This project describes the design and testing of large face ventilation systems for oil shale mining. A design data base was generated by reviewing general industry practice, oil shale industry planning, and technical literature. Conceptual designs for seven different systems were developed and evaluated for suitability. A large, free-standing, jet fan and reversible fan with rigid duct were selected for fabrication and testing. The two systems were field tested in a dead-end heading 55 ft wide by 30 ft high and 320 ft long. System performance was optimized using measurements of air flow direction and air velocity. Total system performance was then measured using SF6 tracer gas released to simulate blast fumes, hot diesel exhaust, methane layering and methane from a blasted muckpile. Field testing indicated that both systems delivered similar performance. The jet fan offered some clear advantages because of its mobility, ease of oper-ation and lower power requirement. It also offered some functional advantages in ventilating for methane because of it high average velocity.

Jan 1, 1985