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By Rose L. Ballard

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are tables that show the principal nonfuel mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. 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. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines. Because of inadequacies in the statistics available, some series deviate from the foregoing definition. For gold, silver, copper, lead, zinc, and tin, the quantities are recorded on a mine basis (as the recoverable content of ore sold or treated). However, the values assigned to these quantities are based on the average selling price of refined metal, not the mine value. Mercury is measured as recovered metal and valued at the average New York price for the metal.

Jan 1, 1981

By George R. Schottler

The Bureau of Mines investigated the distribution of uranium and various methods of ore sampling in a uranium deposit typical of those in the Morrison Formation sandstone of the Ambrosia Lake area, Grants mining district, north-western New Mexico. Chemical and radiometric assays of diamond-drill core samples are compared in detail by statistical techniques, and the assay data are correlated with the stratigraphy of the deposit. Conclusions applicable to ore-reserve estimation in geologically similar uranium deposits are drawn.

Jan 1, 1971

By A. Visnapuu

The Bureau of Mines investigated carbonyl processing techniques for the recovery of the critical metals Ni, Co, Mn, and Cr from domestic primary and secondary sources. In most cases, the source materials require reductive precarbonylation treatment to metallize the contained Fe, Ni, and Co compounds to render them reactive with CO. The critical metals were recovered either by direct conversion to the respective carbonyls or as upgraded products by carbonyl removal of an undesirable metal. Best metal-to-metal carbonyl conversion was under CO pressure, from 80 atm upward, and at 1400 C. Carbonylation was accelerated by the addition of HzS in small quantities. CO pressure, temperature, promoter and pretreatment trends, and other factors enhancing metal carbonyl formation are presented.

Jan 1, 1987

The object of this program was to design and build a self-contained system for remote monitoring of the atmosphere in mines. The system developed uses the mine pager phone line as the primary communication channel and also has the capability of using 208 Hz in the ELF band for wireless transmission through the earth. The depth for through-the-earth trans- mission is expected to be about 80 to 90 meters in high conductivity soil and is limited by the noise level in the ELF band-pass filters. The underground components of the TEM System are energized by mine power through a battery charger - storage battery power supply. In the event of mine power failure the battery capacity is more than sufficient for one week's operation with interrogations every four hours.

By Larry G. Stolarczyk

1.0 FRAMEWORK FOR COMPARISON This document describes the decision factors that bear on the selection of the modulation process for the wireless underground medium frequency (MF) communication system. The selected modulation process must satisfy the Bureau of Mines stated objective of improving general communications within an underground mine. The improvement being sought includes the development of a wireless communication technology of measurable benefit to both mine safety and mine productivity. The improvement will allow wireless communications paths to exist between roving miners. The wireless communication paths will also be made compatible with the existing underground telephone system to extend paging and voice communication throughout the underground mine. The new wireless equipment will include man-pack, vehicular, repeater, and base station transceivers. Repeaters and base stations will feature coupling networks for interfacing with the existing telephone circuits. Frequency modulation (FM) and single sideband (SSB) modulation processes are analyzed in view of the special conditions associated with underground mining. Of primary importance is the tremendous electrical noise generated in an operating mine that could adversely affect communications quality. High noise coupled with high attenuation rate of near field signals forces the communication system to be inherently short range. Fortunately, near field signals can propagate over great distances on underground wires and cables. The framework for comparison is generated by presenting all factors that

By P. W. Jeran, C. M. McCulloch, Maurice Deul

The natural vertical fracture sys tem in bituminous coalbeds is called cleat. Cleat orientation commonly controls the direction of mining with major development paralleling the face cleat. Previous researchers have categorized the origin of cleat as endogenetic, relating the origin of cleat to compaction and coalification, and exogenetic, relating the origin of cleat to tectonic forces. In the coalbeds studied for this report it was found that tectonic forces were the controlling factor of cleat formation. Face cleats were formed as extension fractures during structural deformation, and butt cleats, as release fractures during erosion and uplift. The face cleat of the Pittsburgh coalbed rotates from N 80° W in north- western West Virginia to N 57° W in southwestern Pennsylvania ; the face cleat maintains a perpendicular orientation to the shifting axial trend of local structures . Cleat orientation in other bituminous coalbeds in Virginia, Utah, Oklahoma, and Central Pennsylvania showed a similar relationship to local structure. Directional permeability of coal is directly related to cleat. Holes drilled perpendicular to the face cleat yield from 2.5 to 10 times the amount of gas released as compared with holes drilled perpendicular to the butt cleat.

Jan 1, 1974

By W. A. Selvig

The experiments described herein were made at the request of Committee D-5, on Coal and Coke, American is n Society for Testing Materials, in order to obtain data as to the probable contamination of laboratory samples of coke Then pulverized to pass a No. 63 sieve of tine U. S. Standard Sieve Series2 by methods other than by ball-mills or hard-steel diamond mortars, which methods are specified-in the standard methods of that Society.3 After pulverizing, representative samples were analyzed by the Bureau of Mines at Pittsburgh for ash content to detect any contamination of the samples by the pulverizing apparatus. Preparation of Core Samples for Tests. Two samples of 48-hour beehive coke (Continental and Leisenring) made from Pittsburgh coal were selected for the tests. These cokes were crushed approximately to No. 10 sieve size, by first passing through a jaw crusher and then through a, roll crusher. The crushed coke was then carefully mixed and riffled into portions of about 800 grams each, and sent to three cooperating laboratories for grinding, through a No. 60 sieve. Size tests on these samples shoved the fineness to be as follows: [ ]

Jan 1, 1925

By Timothy J. Rohrbacher

This report presents a U.S. Bureau of Mines study that incorporates coal mining factors, coal recovery factors, and economic factors into the definition of an economically recoverable coal resource. The relationship between these factors to the Energy Information Administration's estimate of U.S. coal resources-the "Demonstrated Reserve Base"-is discussed. The Matewan 7-1/2 minute quadrangle in eastern Kentucky was selected as the initial study area. Results indicate that of the original 1,193 million tons of resource in the quadrangle, only 89 million tons (7.5%) are economically recoverable at a cost of $25 per ton or less. At the current production rate of 5.3 million tons per year, this represents only 16.8 years of remaining reserves.

Jan 1, 1993

By A. L. Johnson

In this Bureau of Mines report, time-resolved infrared emission spectra and corresponding pressure and temperature histories are reported for large-scale propagations of CH4-air, CH4-air-N2, and CH4-air-CF3Br ignitions in a 12-ft-diam sphere. Absolute spectral radiances were obtained throughout combustion over the 1.6- to 4.8-gym range, and the radiance growth patterns for the H20 (2.5-µm) bands are presented as a function of methane stoichiometry and diluent concentration. Flame temperatures were determined from the C02-band emissions, which approximated unit emissivity shortly after ignition. Burning velocities are also given for some of the test-mixture compositions. Measured flame temperatures were in excellent to fair agreement with theoretical adiabatic values for the CH.-air and CH4-air-N2 mixtures; the best agreement was for the stoichiometric CH4-air mixture. The CH4-air-CF3Br mixtures with =2 pct CF3Br gave poor agreement with theory. The measured temperatures were significantly lower during the early stage of combustion; furthermore, the later stage of combustion was uninhibited and yielded unexpectedly high pressures. Supplemental data from a 2-ft-diam sphere at various initial pressures confirmed that the CF3Br inhibition effectiveness decreases with increased pressure. The possible effects of buoyancy, turbulence, and changing kinetics are discussed.

Jan 1, 1977

By Dennis R. Dolinar

Screen material in the form of welded wire mesh and geogrids are used in underground coal mines to prevent the fall of small pieces of rock from the roof between roof bolts. Further, if the screen is installed during the production cycle, roof fall injuries can be reduced significantly. Therefore, the National Institute for Occupational Safety and Health (NIOSH), because of the safety implications, conducted an evaluation of screen materials commonly used in U.S. coal mines to determine their support characteristics and identify the parameters that could affect their performance with respect to controlling the fall of rock from the roof surface. To evaluate the load and stiffness characteristics of the screen, a test frame was designed and installed in the Mine Roof Simulator (MRS) at the NIOSH Pittsburgh Research Laboratory (PRL). With this test set up, the screen is bolted at four corners of the frame and a center load is applied. The test set up allows for up to 20 in of screen deflection while the load and screen defection are continuously recorded. A series of tests were conducted to evaluate the effects of various parameters such as bolt tension, the type of load bearing surface and the size of bearing plates on welded screen performance. The most common screen material used in U. S. coal mines is an 8-gauge wire welded in a 4-by-4-in spacing or aperture. The peak screen load was normally limited by wire breakage. The conditions at the bearing plate influence the nature of the wire breakage. However, the screen stiffness was controlled by slippage at the bearing plates, and by weld and wire failure. The size of the bearing plate had a significant effect on the performance of the welded screen. Therefore, the design capacity of the 8-gauge screen is evaluated based on plate size. For a 6-by-6-in bearing plate the average peak load is 2,900 lb with a stiffness of 250 lb/in. For an 8-by-8-in bearing plate, the average peak load is 4,500 lb with a stiffness of 430 lb/in. These test results are based on a 4-by-4-ft bolt spacing. A geogrid mesh was also tested.

By F. D. Wang

The Bureau of Mines has developed a computer program for evaluating pit slope stability by the finite element stress analysis and limiting equilibrium method. The program includes the finite element method of stress analysis using triangular elements, finite-element model mesh generation, plotting of the model mesh and stress contours, calculation of a factor of safety along a circular or a plane failure surface, and location of a critical circular failure surface. Instructions for preparation of input data, an example problem, and the program listing are presented.

Jan 1, 1972

By John C. Franklin

The Bureau of Mines conducted extensive laboratory and limited field tests to determine whether a polymeric material could effectively reduce the emanation rate of radon gas from uranium ore. In the laboratory 46 different single-coat materials and 14 two-coat applications were tested. The laboratory tests showed that up to 100 percent of the radon gas could be sealed into the rock. Materials tested in the laboratory were polyesters, furan resins, epoxies, latices, and totally inorganic coatings. From the laboratory work six different materials were selected for field testing. The first test was single-coat materials in five static chambers; the second test used two-coat applications in an open chamber. Both tests were conducted in the Dakota mine at Grants, N. Mex. During the second test, the amanation rate of radon gas was reduced up to 62 percent.

Jan 1, 1975

By M. R. Geer

The washability examination of a coal establishes the quality of the product that could be prepared by mechanical cleaning, shows how much impurity would have to be eliminated to attain a particular quality of product, indicates what type of cleaning process would be suitable, and tells whether the coal could be cleaned efficiently, The coal-preparation laboratories of the Bureau of Mines make washability examinations of coal for a variety of purposes. Sometimes these examinations are made as an integral part of research conducted on coal-washing problems. Occasionally they are made on coals mined on Government-owned land or on coals destined for use in Government installations. Often they are made on coals from new fields or new beds in existing fields to help establish the characteristics of the Nation's coal reserves. Whatever the original reason for doing the work, the results often are useful later in evaluating deposits or in the design of cleaning plants. Publication of the results of such studies provides for the widest possible usefulness. This report brings together the results of washability examinations made on 1 coal each from Oregon and Idaho, 2 from Wyoming, 5 from Utah, and 11 from Washington. Material of this nature is inherently difficult to summarize. Some of the coals are so clean} despite full-scam mechanical mining, that they could not be improved materially by washing; others present some of the most difficult preparation problems found in the country.

Jan 1, 1961

By Donald A. Wilson

As part of a continuing effort to maximize metal recovery from domestic secondary resources, the Bureau of Mines investigated a process for recovering the metallic portion of scrap alkaline batteries. A pyrometallurgical method for recovering nickel and cadmium from Ni-Cd scrap batteries previously developed on a laboratory scale, was scaled up to 25-and 43-pound charges. The method employed reduction and/or decomposition in a retort using a minimum of 2.5 percent carbon as a reductant. Metallic cadmium was distilled at atmospheric pressure and a minimum of 900° C. Purity of the recovered cadmium was 99.8 percent minimum and the nickel-iron residue contained less than 0.02 percent cadmium.

Jan 1, 1981

By Robert F. Holub

The Bureau of Mines has evaluated four working-level radiation-measurement methods and optimized them from the inherent and statistical error standpoint. Optimization with respect to various sampling and measurement times yielded no marked improvement over the existing methods. However, when appropriate approximations are made and evaluated, these two-measurement methods can be reduced to simple formulas, eliminating a need to use nomograms. These modified methods also have improved inherent error characteristics. A new method--a combination of two existing methods--with improved inherent and statistical errors has been suggested. All the pertinent equations are given, together with the computer program, so that any two-measurement method can be readily evaluated.

Jan 1, 1980

By T. E. Gray

This report describes the preparation characteristics of the more significant coal beds in Allegheny County, Pa. It is one of a series planned to determine coals suitable for producing metallurgical coke, either as mined or after beneficiation. More than 7 million tons of coal was produced in Allegheny County in 1957. Of this, more than 5 million tons was cleaned mechanically in nine cleaning plants. The Bureau of Mines estimated that, as of January 1, 1953, more than 384 million tons of recoverable coal remained in the county in beds 28 inches or thicker.

Jan 1, 1959

By H. H. Fields, T. W. Goodman, Joseph Cervik

The Bureau of Mines conducted research to determine the effectiveness of long holes drilled in solid virgin coal in degasifying an area of the Pitts- burgh coalbed showing that horizontal holes drilled into a virgin coalbed from the bottom of any shaft will effectively remove methane gas in commercial quantities from the Pittsburgh coalbed. The in situ pressure at a depth of 214 feet into the coalbed and the average gas and water flows from the five degasification holes were 3 lb/in2 gage and 860,000 ft3/d and 1.7 gal/min, respectively. On June 19, 1975, after 593 days of degasification, a compressor was installed and pipeline quality gas was introduced into a commercial pipeline. As of June 1, 1976, after 1,022 days of degasification, over 753 million cubic feet of gas had been drained and 117 million cubic feet of gas had been purchased by the gas company for use in the local community of Wadestown, W. Va. The gas drained to date is six times the gas estimated to be in the area subtended by the holes. Methane emissions at the working face of 1 West mains, Federal No. 2 mine has been reduced by 50 pct, proving the value of methane drainage by horizontal degasification holes drilled from shaft bottoms ahead of mining.

Jan 1, 1976

By Leon E. Esparza

The Bureau of Mines studied 780 acres of the 24,130-acre Sheldon Contiguous Wilderness Study Area (CA-020-1012) in 1985. The study was done at the request of the Bureau of Land Management and authorized under the Federal Land Policy and Management Act (Public Law 94-579, October 21, 1 976) in order to evaluate the mineral resources. The study area is located in Washoe County, NV, about 35 miles northeast of Cedarville, CA. A search of county courthouse records and an examination by foot traverses through and adjacent to the study area did not reveal evidence of any mining or mining exploration activity past or present. In addition, evidence of any form of rock alteration was not observed. Evidence of mineral resources is not apparent. Although basalt, the only rock-type present in the study area, can have some limited industrial applications, sources closer to potential markets probably would preclude rock from this area being economically competitive. 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 the Sheldon Contiguous study area at the request of the BLM (U.S. Bureau of Land Management). The USBM examines 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. Although the immediate goal of this and other USBM mineral surveys ;s to provide data for 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 G. G. Morgis, J. J. Forbes

"INTRODUCTION The greatly diversified and increased uses of beryllium and its con& pounds in recent years have focused attention on the health hazards incident thereto. The Bureau of Mines has a fundamental interest in safety and the elimination or reduction of health hazards in the mineral and allied industries, and it recognizes that serious hazards are inherent in the production and use of beryllium and its compounds. This circular presents a review of the literature pertaining to such health hazards but does not describe original research by Bureau personnel. Most of the bibliography has boon either quoted in part or abstracted in an effort to present information in a comprehensive and readable form.In reviewing the literature, differences of opinions wore recognized in the writings of the respective authors, but no attempt was made to evaluate such differences. This presentation was devoted strictly to reporting without editorial comment.SUMMARYAlthough beryllium was known to industry for about 150 years, its toxicity did not present any serious problems in the United States until the advent of World War II, when the increased use of this element and its compounds brought to light several toxicologic reactions occurring primarily in the lungs and skin of workers handling it. The pulmonary effects, characterized as acute pnoumonitis and chronic pulmonary granulomatosis in beryllium workers, are far more serious than the dermatological manifestations.The addition of beryllium to the list of toxic industrial metals has boon so recent that there is still some confusion in the clinical picture. Data on magnitudes of exposure likely to be responsible for the production of disease are not yet adequate. There appears to be no relation between the severity of exposure and the development of cases some of those having had severe exposure have not developed a reaction, whereas those having a slight exposure in some instances have developed a response."

Jul 1, 1950

By Clarence O. Babcock

This report describes the results of a Bureau of Mines investigation in which an elastic inclusion, orebody, or mining system is replaced for purposes of analysis with an imaginary effective inclusion of rectangular shape that encloses the region. This effective inclusion has averaged physical properties that are directly related to the average inclusion stresses. The results were in excellent agreement with those predicted by Donnell's theory (2)2 for an isotropic elliptical inclusion in a state of plane strain for all height-to-width ratios and for all degrees of inclusion hardness from very soft to very hard. The results are exact for an isotropic circular inclusion and provide an easy method of evaluating the stresses obtained by cylindrical inclusions in boreholes when the Poisson's ratio for both host and inclusion equals 0.25 for plane strain or 0.333 for plane stress. The theory was also used to predict the average stresses in 48 finite-element models of single transversely isotropic inclusions of ovaloid and rectangular shape. An interesting and useful observation from this work was that the forces on elliptical inclusions in the x and y directions, produced by applied uniaxial stresses in the y and x directions, respectively, were equal in magnitude but opposite in sign when the applied stresses were equal. This occurred when the plane strain condition was used with a Poisson's ratio of 0.25. The practical usefulness of the method is given by treating a variety of mining problems: (1) The average stresses in an orebody of irregular shape; (2) the average stresses in single-level room-and-pillar mining systems; (3) the average stresses in multiple-level room-and-pillar mining systems; (4) the effect of mining sequence on the average stresses produced during mining; (5) the stresses in cylindrical borehole plug related to host rock stresses as a function of plug hardness; and (6) methods for simplifying finite-element analysis of complex structures.

Jan 1, 1974