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By Kray Luxbacher, Mario Karfakis, Erik Westman, Peter Swanson

Three-dimensional velocity tomograms were generated to image the stress redistribution around an underground coal longwall panel to produce a better understanding of the mechanisms that lead to ground failure, especially rockbursts. Mining-induced microseismic events provided passive sources for the three-dimensional velocity tomography. Surface-mounted geophones monitored microseismic activity for 18 days. Eighteen tomograms were generated and high-velocity regions correlated with high abutment stresses predicted by numerical modeling. Additionally, the high-velocity regions were observed to redistribute as the longwall face retreated, indicating that velocity tomography may be an appropriate technology for monitoring stress redistribution in underground mines.

By John H. Soulé

This paper describes the location and general features of the ?Red Bed? or sandstone copper deposits in southeastern Colorado and New Mexico. Most of the areas containing this type of deposit were visited, and many deposits were examined. Some deposits were not visited because of lack of information as to their location. In the large area covered a great variety of climatic, geographic, and topographic conditions exists. Some of the deposits are in arid areas, whereas others are in heavily forested regions. Altitudes range from 3,400 to 9,200 feet, and the terrain varies from flat plains to rugged mountains. Transportation is a difficult problem in most of the districts, involving long truck hauls to a railroad and long rail hauls to a smelter.

Jan 1, 1956

By Gary E. Sherman

This report presents a Bureau of Mines study on the cost of mine permitting and compliance with environmental regulations in Alaska. It discusses permitting requirements and procedures for placer and lode mines. Placer miners must comply with recently established (1988) water quality regulations and effluent treatment requirements. To estimate the impact differing treatment options (no recycle, 100% recycling, and flocculation) have on a placer mine's rate of return, three models (1,500, 1,000, and 500 yd3/d) were simulated. Rates of return for these models show a marked decrease as effluent treatment is increased. The incremental increase in operating cost from one treatment option to the next is relatively small; however the opportunity cost of lost production if' significant and accounts for the decreasing rate of return with increased effluent treatment. Lode mines face greater costs for permitting and compliance than similarly sized placer mines as a result of the impact of the operation. Direct permitting costs for lode mines range from 2 to 6% of total project cost, with 4% the most common figure cited by industry. Total costs for permitting and compliance are approximately double those for permitting. Indirect costs associated with compliance include mitigation, monitoring, and reclamation.

Jan 1, 1991

By Kenneth M. Maas

The Bureau of Mines inventoried all lands in Alaska to determine the availability of land for oil, gas, and coal leasing. Acreage for onshore oil, gas, and coal basins was digitized as was land ownership data. Regulatory policy concerning oil, gas, and coal leasing for various government agencies and private concerns was determined. Oil and gas basins underlie 79.4 million acres of Alaska's 378 million acre landbase. Federal agencies manage 44 million of these acres. The Bureau of Land Management is the lead agency for most oil and gas leasing on Federal lands. Lands have to be specifically opened for oil and gas leasing to be available. The state of Alaska manages 21.1 million acres underlain by these basins. More than 80 percent of this acreage is available for resource development. Native corporations manage the remaining 14.3 million acres of favorable oil and gas land. Coal basins underlie nearly 51 million acres of Alaska. Of this land, 26.4 million acres are under Federal jurisdiction. The state manages 17.3 million acres of land underlain by coal basins. Nearly 7.3 million acres of favorable coal lands are managed by Native corporations.

Jan 1, 1991

This chapter summarizes data on crude mineral production for the United States, its island possessions, and the Common-wealth of Puerto Rico. Included also are tables that show the principal mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. Except for the mineral fuel commodities, the detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. In October 1977, responsibility for the collection of data on mineral fuels-coal, petroleum, natural gas, and natural gas liquids-was transferred to the newly created Department of Energy. Although chapters covering these commodities will no longer appear in Volume I of the Minerals Yearbook, quantity and value data have been included in most of these summary tables to maintain statistical consistency in State and national value of overall crude mineral output. This shift in responsibility has also resulted in changes to the composition of the "Nonmetals" and "Mineral Fuels" groups in table 1 and table 2. The commodities-asphalt and related bitumens (natural), carbon dioxide (natural), helium, and peat-have been removed from the "Mineral Fuels" group, and are now included under the "Nonmetals" group. There has been no change in the components of the "Metals" group.

Jan 1, 1980

By Piyush K. Dutta

This report describes the design, development, manufacture and incorporation of noise control features on a jumbo drill and the results of successful tests of this drill in surface and underground mines. The noise-reducing features developed under this program are applicable to future designs of jumbo mounted drills that can be cost effectively manufactured and have the potential to reduce noise levels at the operator's position from 115-120 dBA to 95 dBA or less without a reduction of currently attainable drilling rates.

Jan 1, 1985

By David Schlain

The Bureau of Mines investigated methods for electrodepositing platinum-group metals from molten cyanide baths. The preparation of thick, protective coatings on molybdenum, Inconel, graphite, stainless steel, copper, and other structural metals were studied, as well as the electroforming of platinum and iridium crucibles. Iridium, rhodium, and ruthenium can be electrodeposited under an inert atmosphere, while platinum and palladium require the presence of air. Electrolytes may be prepared by direct-current electrolysis in NaCN or mixtures of NaCN and KCN using anodes of the particular platinum-group metal. When the concentration of metal increases to about 0.3 or 0.4 percent, the deposits become bright, adherent, and coherent. Current densities may be 10 to 25 ma/cm2, and plating rates are often 0.5 mil/hr. Platinum and palladium baths deteriorate because of the oxidation of cyanide to cyanate and carbonate, and the precipitation of metal. Changes in the platinum cyanide bath are relatively slow. The protection against oxidation afforded by the platinum-group metal coatings is evaluated by testing encapsulated specimens in a thermogravimetric balance. Surface pretreatment and the use of undercoats are discussed.

Jan 1, 1977

By J. O. Lewis, Carl H. Beal

The material for this paper was collected for the most part by C. H. Beal during the years 1916, 1917, and 1918. Many of the conclusions reached in regard to the life of oil wells have already been published by the Bureau of Mines 1 but those presented in this paper deal particularly with the theoretical aspects of oil production. The report discusses some of the fundamental factors governing oil production, taking up first the conditions affecting the. amount of oil in the oil sand, then those factors that control the rate of production of oil wells, and then discusses several related problems, most of which deal particularly with the effect of the production of one well on that of another.

Jan 1, 1921

By W. D. Mcmillan

Kaolin, or china clay, is the term applied to a group of hydrous aluminum silicates. Because of its purity, light color, and refractory properties, kaolin is used extensively in the manufacture of high-grade ceramic wares and as a filler by the rubber and paper industries. Although there are numerous pottery and enamelware plants in Texas, and large rubber and paper industries; all of the kaolin used in these plants is from other States, There are two known occurrences of kaolin in Texas, namely, the Leakey deposit in Real County and the several deposits of the Medley district in southern Jeff Davis County. An investigation of the Mueller kaolin deposit in the Medley district was undertaken by the Bureau of Mines. Following an examination of this deposit by W. D. McMillan, engineer in charge of the Texas field office of the Bureau of Mines, a proposal was made to investigate the deposit by diamond core drilling.

Jan 1, 1949

By Terry R. Neumann

During 1984, at the request of the U. S. Bureau of Land Management, U.S. Bureau of Mines personnel conducted a mineral survey of the 28,600-acre South Pahroc Range Wilderness Study Area (NV-050-0132). The Wit derness Study Area is located in Lincoln County, NV, about 900 miles north of Las Vegas. Five mineral properties and two mineralized zones were examined during this study; of these, one mineralized zone, two small prospect pits, and part of two claims are within Wilderness Study Area boundaries. Perlite resources were identified in the study area; however, no significant metallic mineral values were noted at any of the sites. The Wilderness Study Area is dominated by a Tertiary volcanic sequence consisting of an interlayered series of tuffs containing thin beds of volcanic pebble gravel, sandstone, and perlite. At the base of the exposed volcanic section, perlite occurs along a 2.4-mile-long zone that parallel s the study area's northeastern boundary. The perlite is suitable for filtration, insulation, and soil conditioning purposes, Because of prohibitive operation and transportation costs, the estimated 6 million tons of perlite occurring inside the South Pahroc Range Wilderness Study Area are classified as an indicated subeconomic resource.

Jan 1, 1986

By H. S. Benson

This report documents, from concept through field testing, the pan scraper Wheel Slip Monitor. The function of this device is to instantly warn the scraper operator of wheel slip and thus enable him to take immediate corrective action. Knowledgeable pan scraper people recognize that the preponderance of scraper tire damage and wear occurs during useless wheel slip when the scraper operator attempts to increase machine draft beyond what traction will allow. The resultant shortened tire life has become very expensive. The Wheel Slip Monitor reported here provides the means for relieving the scraper operator of attempting to judge wheel slip on tires he cannot see. Direct and intuitively understandable audible and flashing light warnings tell the scraper operator which wheel is slipping and also indicate the relative magnitude of the slip. Beside the Wheel Slip Monitor's patent utility as a real time operator aid, it has unique potential for application to extended term wheel slip history acquisition under field conditions. This information has never been easily available and it promises practical value in pan scraper management.

Jan 1, 1983

By J. Bennetts

As part of its mission to develop technology that will help increase the supply of critical and strategic minerals from domestic resources, the Bureau of Mines has investigated methods for beneficiating platinum-group metal ores from the Stillwater complex, Montana. This report presents the result of a bench-scale study employing froth flotation to recover a sulfide concentrate containing platinum-palladium values from a mineralized gabbro. Best results were obtained with a flotation scheme utilizing a mercaptobenzothiazone collector and sulfuric acid. Rougher concentrates containing approximately 11 oz Pt-Pd/ton and 90 pct of the metal values in the ore were obtained. Subsequently, cleaner concentrates containing approximately 26 oz Pt-Pd/ton and between 80 to 85 pct of the Pt-Pd values in the ore were prepared.

Jan 1, 1980

By Frank A. Peters

This evaluation of the sulfurous acid process for the production of metallurgical-grade alumina is the first of a series concerning various known methods of extracting alumina from low-grade aluminous materials and was undertaken to permit comparison with other processes. In the process with which this Bureau of Mines report is concerned, calcined clay is leached under pressure with 20 percent sulfurous acid and then filtered to remove a siliceous residue. The aluminum sulfite remaining in the filtrate is precipitated as a monobasic sulfite which, together with iron sulfite, is then decomposed under pressure to form a crude alumina hydrate and iron oxide. This intermediate product is purified in a modified Bayer process to yield alumina suitable for electrolytic reduction to aluminum. A study estimate (16)3 is used for these evaluations. The capital cost, not including land, is estimated at $95,701,600 on a Marshall and Stevens index basis of 240.0 for a plant producing 1,000 tons a day of alumina or 350,000 tons a year. The annual operating cost for this size plant is estimated at $22,831,100 or $65.23 per ton of alumina using clay at $1 per ton. Depreciation and local taxes are included in the estimate, but profit and Federal taxes are not considered.

Jan 1, 1962

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

Provide the U.S. mining industry with technology for designing environmentally sound, low-cost in situ leach mining operations to produce copper from small, deep, and/or low-grade copper oxide deposits. Approach Investigate the feasibility of a new mining method--in situ leach mining-as an alternative to conventional mining for copper. Study fundamental leaching technology that will facilitate future commercial operations. Develop guidelines and procedures that will enable mine operators to design and evaluate in situ leach mining operations for any specific copper oxide deposit.

Jan 1, 1989

By Virgil A. Marple

The objective of this contract was to conduct characterization, evaluation and/or calibration studies of instrumentation used for measuring the quantity of respirable dust in mining atmospheres. Initially, this work involved the upgrading and detailed evaluation of the aerosol test chamber and the development of impactors with respirable classification characteristics. These were used as standards in the chamber for measuring the quantity of respirable dust based on either the ACGIH or BMRC respirable dust criteria. A program was then conducted to calibrate several photometers. In addition, the mass sensitivity of the GCA RAM-1 photometer to water droplets in the respirable size range was determined. Three additional studies were also made in this program. First, an experimental study was performed to ascertain the effect of crosswind, cyclone orientation and particle size on particle sampling and penetration through the 10 mm Dorr-Oliver cyclone. Second, a theoretical study was conducted to refine the theory used to predict the particle collection characteristics of impactors. Third, filter samples with known quantities of diesel and coal particles were produced and delivered to the B. of Mines for testing a Raman scattering analysis technique to discriminate diesel particles in the presence of coal dust.

Jan 1, 1984

By Ned Baker

Details are given of a Hydride Fuel System to provide 5 kg of HZ to fuel a Caterpillar 3304 engine previously modified to operate on hydrogen fuel and intended to power an underground mining vehicle. The Fuel System was installed onto the engine and the Engine/Fuel System tested under cold start conditions and a full range of engine loads and speeds. Refueling tests were also performed. The fuel system tested will support full engine power and allow delivery of at least 3/4-power on a continuous basis, from cold start conditions.

Jan 1, 1983

By Agnes Y. Lee

As part of the U.S. Bureau of Mines program to improve base metal leach systems, pressure leaching of galena (PbS) concentrates in fluosilicic acid (H2SiF6) solution was investigated. Lead extraction was 93 pct when PbS was pressure leached in H2SiF6 at 95° C with 2OO-psig O2 pressure for 40 min, using ferric nitrate [Fe(N03)3] as a catalyst. The effects of several catalysts, O2 pressure, time, and acid concentration on leaching were determined. The purified leach solution was electrowon to recover high-purity Pb metal. The H2SiF6 used in leaching and electrowinning can be recycled continuously. A flow diagram was proposed based on this investigation. Elemental sulfur (SO) was recovered from the leach residue by solvent extraction. A method was also developed for treating the flnal residue to segregate the important byproduct elements such as Ag, Cu, and Zn and enable their recovery by standard commercial processes.

Jan 1, 1990

By Doris M. Hyde

The 350,000-barrel-per-day Bahamas Oil Refining Co remained closed throughout 1986. Financially troubled Charter Oil Co., joint owner of the refinery with Chevron Oil Bahamas Ltd., agreed in principle to have Chevron assume full ownership in return for canceling debts owed Chevron. Finalization of the agreement was pending at yearend. Burmah Oil Ltd. took more than a $30 million loss on the sale of its interest in South Riding Point Grand Bahama Transshipment Terminal to South Riding Point Terminal Holding Ltd.

Jan 1, 1988

By Martin H. Rogoff

This publication combines a critical review of the literature on the microbiology of coal with an introduction to those areas of microbiology related to studies of coal as a biological material. The attack on coal by microorganisms as yet remains doubtful. Only the low-rank coals contain an indigenous microbial flora, and even these organisms are not peculiar to coal, but are common soil and water forms. No experimental data have as yet been presented, either in the literature or in the present work, which unequivocally demonstrate the oxidation of coal by microorganisms. Reasons for the resistance of coal to such attack, including insolubility, physicochemical structure, steric hindrance of enzyme action, and the presence of antibiotic materials in coal are discussed. Microorganisms do attack large aromatic molecules and the mode of oxidation of aromatic ring systems by bacteria is presented. Well-defined pathways are known for the oxidation of polycyclic compounds with one to three rings, and these paths with their key intermediates are described and related to the possible oxidation of coal.

Jan 1, 1962