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By Manuel Gomez

A computerized moving average technique was developed to interpolate coal seam characteristics between sample points. The interpolative method coupled with multivariate regression analysis and simulation procedures was used to forecast coal properties not readily obtained from an analysis of drill core samples. Coal property forecasts were of two kinds: (1) specific mine property forecasts that are suitable for mine product control and yield a good approximation of the local variation along both the vertical and horizontal axes of the seam, and (2) regional estimates where much of the local seam variation is smoothed out, but the general trends are maintained. Forecasts of the volatile matter, ash, total sulfur, and the heating value for part of the Pittsburgh seam located in Ohio, Pennsylvania, and West Virginia were in good agreement with independent evaluation data. Spatial configuration for preparation characteristics, particularly, the effect of crushing on sulfur release, low-and high-temperature carbonization properties, the Hardgrove grindability index, the coal hardness index, gasification variables, and hydrogenation factors were constructed for the same area of the Pittsburgh seam. These forecasts may be developed from drill core data collected in the exploration phase of mining. The results, which may take the form of a series of maps, are useful to mining, chemical, and combustion engineers, to economists and mine managers, as well as to coal users for mine design, economic analyses, energy forecasts, utilization studies, mine product control, and environmental control and programming.

Jan 1, 1974

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

2. Preliminary Study - Initial Probing 2. 1 Introduction Initial probing of the mine passage is required prior to the emplacement of the sealant material or deployment of the seal checker system. Factors which are of interest in sealing and checking include a. size and condition of the mine passage b. location of the borehole with respect to the ribs c. the presence of water flows d. the proximity to an intersection The importance of each of these factors depends strongly on the sealant material. Because the sealant material had not been selected at the time of the initial probing study, a broad survey of probing techniques was conducted. The capabilities and limitations of each technique as they applied to probing through the borehole were identified. To facilitate this comparitive evaluation, Table I was prepared which lists all passage conditions which might affect the emplacement of sealant material in the passage. The most satisfactory techniques for observing each condition of interest are listed together with the effects of the observation on the sealing operation. Table II summarizes the environmental conditions likely to be encountered in the passage being probed and the physical

Jan 1, 1973

This Part describes a mine pager phone to public telephone interconnect sys tem that permits mine paging telephones to be selectively interconnected with the public telephone system, as illustrated by Figure 1. This interconnect concept was first conceived and demonstrated in breadboard form by H. E. Parkinson of Industrial Hazards and Communications, PMSRC, as one means for providing improved emergency and off-hours communications. The third-generation prototype unit described in this Part was designed and fabricated by Arthur D. Little, Inc. This unit is a small desk-top or wall-mounted unit that connects directly to both the public telephone line and the mine pager phone line, and requires no modifications to either the public dial telephone or mine pager phones. As part of this task, ADL also built, under a very compressed time schedule, a second-generation prototype unit suitable for reliable demonstration of the interconnect concept during the Bureau's technology transfer seminar on mine communications in March 1973. * A major objective of the design of the third-generation unit described in this Part was that it be compatible with present mine pager phone systems utilizing DC voltage on the mine phone line to activate the phone loudspeakers. Therefore, this unit was designed to operate in a push- to-talk, push-to-listen mode that accommodates the inherent design differences and operation modes of the mine phones of different manufacturers. Though this push- to- talk, push- to-listen mode of operation may seem slightly unusual at first sight, we have found it is easily learned by new users. However, mine phone manufacturers wishing to expand their product lines with such an interconnect system will probably find it to their advantage to customize the design of this system to their particular mine phones, thereby utilizing the unique attributes offered by their individual product lines. This customization should not be difficult, and Section III below suggests some of the features that can be easily added to future designs. Detailed parts lists and circuit schematics for the present third-generation proto- type system can be obtained from the system manual submitted to PMSRC and placed on public file.

Jan 1, 1974

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 the 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.

Jan 1, 1984

By Robert L. Crosby

The Bureau of Mines investigated the substitution of cement copper powder for commercial copper powder in an Fe-7 pct Cu-l pct C powder metallurgy alloy. Copper powders from six different commercial cementation operations were separately upgraded by screening and hydrogen reduction. They were then mixed with commercial iron and graphite powders to form the Fe-7 pct Cu-l pct C alloy. Various chemical and physical properties were determined on the upgraded cement copper and the alloy powders. Mechanical, physical, and chemical properties were determined on green and sintered specimens made from the alloy powders. Mean tensile and bending strength of sintered specimens were significantly lower than the means from specimens made from commercial metal powders. The lower strengths are apparently related to poor sinterability.

Jan 1, 1970

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 the 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.

Jan 1, 1985

By B. J. Dalton

The Bureau of Mines Helium Research Center has as a long-range objective the development of an equation of state for helium that will allow all of the thermodynamic properties to be calculated within the accuracy with which they are known. If this objective is to be realized, a method of calculation must be known. This report gives the principles of the method we use in such problems. A computer program was developed for predicting these properties, including those at the critical point, that is perfectly general and applicable to any equation of state. To demonstrate the efficacy of our method, this computer program was used to evaluate thermodynamic properties of a Redlich-Kwong fluid in the two-phase region. Expressions for calculating various thermodynamic functions specific for this particular equation of state are derived. Numerical values are tabulated and graphs are presented for all functions calculated. It is shown that for a Redlich-Kwong fluid there are finite discontinuities in (1) the second temperature derivative of the Gibbs free energy or chemical potential at the critical point, (2) the second derivative of the vapor pressure curve with regard to the temperature on passing through the critical point, and (3) the measured heat capacity at constant volume on passing through the critical temperature when the calorimeter is filled to the critical density. It is also shown that the heat of vaporization is infinite for a Redlich-Kwong fluid at absolute zero.

Jan 1, 1969

By A. W. Henderson

The growing importance of halide metallurgy for preparing high-purity metals has stimulated research to extend halogenation reactions to the direct extraction of metals from low-grade sources. This Bureau of Mines investigation involves a pioneering study of chlorination reactions in the presence of a fluorine donor. Tin slags containing tantalum and columbium and a zircon concentrate containing a relatively high ratio of hafnium to zirconium were studied. Direct chlorination of these materials at 500° C. yields only a 5-percent conversion of tantalum and columbium or zirconium and hafnium to anhydrous chlorides. This investigation showed that small additions of calcium fluoride to the reaction increased the recovery of tantalum and columbium to 95 percent and the recovery of zirconium and hafnium to 27 percent. These results were achieved with ratios of calcium fluoride to mineral or slag of only 0.2. Silica, the major impurity in the materials studied, was found to be converted to silicon tetrafluoride during chlorination in direct proportion to the quantity calcium fluoride added to the charge. However, large additions of calcium fluoride decreased the volatility of the resulting halides of tantalum, zirconium, and hafnium. Smaller amounts of calcium fluoride also favored recovering minor metal constituents in the zircon concentrate (uranium, thorium, and rare earths).

Jan 1, 1962

By P. L. Loyselle, B. D. Comilsen, D. H. Carlson, J. H. Johnson

"In-mine airborne particulate samples have been successfully collected and the relative amounts of diesel and coal determined using the Laser Raman Quantitative Analysis (LRQA) method. This method allows analysis of filters which have been collected by a method similar to that used to determine the airborne respirable dust concentration in us underground coal mines. Samples were taken near the feeder-breaker, on haulage vehicles, and in the returns. Sampling methodologies were developed for coal-only and diesel-only particulate reference samples with sufficient filter loading for the LRQA method. A statistical analysis of reproducibility has been carried out. Samples have been collected simultaneously at two locations using the LRQA and the size-selective sampling methods. Good agreement between the two methods has been found.INTRODUCTIONThe goal of this research has been to develop the Laser Raman Quantitative Analysis (LRQA) method to measure the composition of respirable particulate, i.e. the fractions of coal and of diesel particulate, in the mine ambient air. In earlier Bureau of Mines sponsored research, we successfully demonstrated that the LRQA method could be used to measure the fraction of Diesel Particulate Matter (DPM) in coal/diesel particulate mixtures which were prepared in the laboratory.(I) 'The immediate objective was to test and refine this LRQA method on samples collected in a diesel underground coal mine.Specific objectives required to meet this goal include:I) Develop in-mine sample collection methods which will insure sufficient particulate loading on filters for LRQA. ,2) Develop methodology for in-mine collection of reference samples (""coal-only"" and ""diesel-only"" filters) which arc required for quantitative LRQA. 3) Analyze precision and accuracy of the LRQA method. 4) Compare composition measurements with another analytical method, i.e. the University of Minnesota/Bureau of Mines size selective sampling Micro-Orifice Uniform Deposit Impactor (MOUDI) method.An advantage of the LRQA method is that it allows analysis of filters which have been collected by a method similar to that used to determine the respirable dust concentration in US underground coal mines. No new sampling instruments and techniques are required. Transfer of sample from collection substrate to analysis substrate is not necessary. Furthermore, other analyses can be made on the same sample since the technique is nondestructive."

Jan 1, 1988

By D. B. Dow

The appearance of water in an oil field is the forerunner of various difficulties, and probably represents the greatest technical problem that the producer must face. Water conditions bear-directly on the quantity of oil recovered, and the length of the life of a field. Presence of mater increases the cost of operation, for example, gifting costs. On account of the corrosive action of oil-field waters on pumps and other equipment, frequent replacement of equipment is necessary. Furthermore, water may affect the marketability of the oil produced, as detrimental emulsions of water in oil (?B.S.?, "cut oil", etc.) are often formed. The writer has recently completed a study of oil-field emulsions. The present paper deals with the factors responsible for the formation of emulsions. This will be followed by another dealing with methods now utilized for dehydrating oil-field emulsions, and by a third dealing with the physical chemistry involved in the formation and resolution of such emulsions.

Jan 1, 1925

By Paul B. Harder

Round Mountain Gold (RMG) in central Nevada, reports that over a nine-year period and a million operating hours, its fleet of 150-ton and 190-ton haul trucks has averaged better than 93% availability, with some of the trucks approaching 70,000 operating hours. Repair costs have been far below industry averages. Mine operations manager Pete Kesl credits the high availability and low repair costs to a succession of Product Support Agreements between RMG and Caterpillar dealer Cashman Equipment. He adds that good equipment and a high level of trust and co­operation between all parties to these agreements have been essential to their success at Round Mountain.

Jan 1, 1998

By R. D. Leitch

Tests have recently been conducted by the Bureau of wines on the ignition hazard of exposing heated filaments of electric mine lam bulbs in an explosive mixture of methane and air. This investigation was undertaken in order to settle a question that had arisen in connection with the safety of miners? electric lamps. For several years, in view of former studies made by the Bureau and reported in Bulletin 524, the fact that the heated filaments of even low voltage, lour candlepower bulbs constitute a danger was generally accepted by the Bureau's engineers. These early tests, as well as subsequent tests, were conducted with Pittsburgh natural was as the testing medium.

Jan 1, 1925

Continuous remote sensing of methane concentration in underground mines. Approach A methane transducer, developed as a fixed point rib-or face-mounted operating device, measures ambient levels of methane and produces a signal that is proportional to the measured concentration. How It Works The methane transducer, developed under contract for the Bureau of Mines, uses a catalytic-type sensor which will detect methane concentration. The transducer is mounted vertically, as shown. This type of mounting minimizes dust accumulation on the sensing element, which might cause degraded operation. The unit must not be located in an area where water can continuously drip or run on It. The transducer generates an electrical signal proportional to methane concentration at the sensor. A sensor failure output indicates the status of the sensing element A circuit within the methane transducer detects whether the sensing element is shorted or open. A high signal (approximately 8 Vdc) on the failure output Indicates the sensor element is operating In Its normal range. A low output (less than 1 Vdc) indicates an element fault. The methane transducer, enclosed in a stainless steel

Jan 1, 1982

By S. E. Khalafalla

The Bureau of Mines investigated the metallothermic reduction of copper oxide as a function of temperature, reactant proportions, form of reductant, and gaseous environment, using iron and steel scrap reductants. The reaction proceeded rapidly with powdered iron at temperatures above 560° C, attaining over 95 percent copper metallization within 3 hours. The importance of inter-reactant contacts on the extent of the reaction was evident from the variable, but usually lesser, degree of metallization obtained with iron from tin cans and automobile steel scrap. Reduction decreased as the molar ratio of copper to iron increased between 1 and 3. The most favorable gaseous environment for the reaction was a static helium atmosphere containing about 0.6 percent water vapor. Ferrothermic extraction of copper from its oxides appears to be essentially a "solid-state cementation" process. While ordinary cementation processes must be preceded by leaching, the ferrothermic method avoids this generally slow step and also the water pollution caused by the leaching agents. Sulfidic copper concentrates could likewise be reduced with metallic iron following their complete oxidative roasting.

Jan 1, 1969

By Fred A. Williams

The cause of many deaths and extensive property damage in coal mines resulting from explosions and mine fires has been directly attributable to electric cable failures (including splice failures). The Federal Bureau of Mines data show that out of 355 underground coal mine fires investigated from July 1952 to January 1960, 103 (29 percent) were directly related to trailing cables. These cable failures resulted in the death of 7 men and injuries to 37 others. These potential hazards have become greater, obviously, through the widespread adoption of mechanized mining methods with electric-driven machinery powered through trailing cables according to Young,4 68.1 percent of the total bituminous and lignite production of the United States was mined underground in 1959. About 85 percent of this production was attained by mechanized loading methods. A large majority of the mines using the hand- loading methods also used equipment with trailing cables such as cutting machines, drills, and gathering locomotives. The problem of minimizing the loss of life, resources, and equipment from cable failures should be of concern to the management of all coal mines. It would be misleading to imply that no consideration has been given to the problem and its associated hazards. Through research cable manufacturers have endeavored to develop trailing cables that will withstand the severe service imposed by underground mining conditions. Technical research groups have undertaken studies for determining improved procedure and materials for field splices. Coal companies have instituted cable maintenance programs with a view toward the reduction of cable failures and consequent improvement in safety and efficiency of operations. Safety agencies are alert to unsatisfactory cable handling practices, poor workmanship in field splicing, mechanical

Jan 1, 1962

By R. Craig Smith

The Bureau of Mines conducted a study of production costs for the secondary lead industry and determined costs for present, pending, and proposed environmental legislation. Operating costs for smelters by capacity groups range from 16.8 to 19.6 ¢!lb of refined lead. Present regulatory compliance costs for these groups range from 2.2 to 2.4 ¢!lb. Pending compliance costs could add 3.5 ¢!lb of refined lead, and proposed regulations could add another 1.3 ¢!lb. The individual capital costs necessary to comply with pending environmental regulations are estimated to be $1.8 million for small smelters and $10.4 million for large smelters. Proposed regulations could require additional expenditures from $1.9 million for small smelters to $4.9 million for large smelters. These cost estimates, based on average 1985 dollars, indicate that pending and proposed legislation could add significantly to capital and operating costs of the secondary lead industry. These regulatory compliance costs may result in a loss of up to 40 pet of secondary lead production capacity.

Jan 1, 1987

By Jacqueline H. Jansky

The Bureau of Mines conducted a study to determine the relation-ship between geologic features and linears. Cleats, kettlebottoms, and roof rolls were mapped and superimposed on the linear plots for a coal mine in West Virginia. No clear relationships were evident. This may be due, in part, to the mining practice of leaving head coal, which obscures geologic features that may exist in the roof. Future studies should concentrate on mines where roof is extensively exposed.

Jan 1, 1982

By James E. Hill

In the course of exploratory drilling during World War II by the Bureau of Mines under the Strategic and Critical Minerals investigations Program, a problem arose as to the ultimate disposal of the drill core resulting from that program. The difficulties experienced in obtaining factual information to evaluate mineral deposits examined (during that program) influenced the Bureau in a decision to catalog and store the drill cores for future reference. Initially, the drill cores were stored at the nearest Bureau of Mines station that had space available for the purpose. Recently the Bureau stations at Minneapolis, Minn., and Denver, Colo., were designated as the locations of permanent drill-core storage facilities. Drill cores that are retained from Bureau of Mines mineral-exploration projects are stored at these two locations and are given preference in selecting cores for storage. Drill cores are accepted also for storage from other Government agencies, State agencies, private companies, or individuals on the basis of available facilities and consistent with the significance of the core in relation to Bureau of Mines objectives and national interest. Selection and acceptance of such drill core are determined by the Bureau of Mines. The drill cores stored at the two locations are available for inspection by any person having a legitimate interest in the mineral deposits represented by the cores. Approximately 1,850,000 feet of drill core can be stared in the facilities now available to the Bureau of Mines. Approximately 475,000 feet of drill care is stored or scheduled for storage at Minneapolis, Minn., and 240,000 feet of core stored or scheduled for storage at Denver, Colo. A list of drill core now in storage at the Bureau of Mines core-storage facilities at Denver and Minneapolis is included as appendix A.

Jan 1, 1957

By J. W. Adams

Measurements of surface magnetic field noise were made at various locations over the Geneva Coal Mine near Price, Utah, on June 12, 1973. The locations selected were on the surface over emergency locator beacons underground at depths between 3S0 meters (1150 ft.) and 488 meters (1600 ft.). The surface terrain where these measurements were made was mountainous, and access was difficult. There were no power lines within several miles, and the weather was clear; therefore, the magnetic noise levels were about as low as will normally occur. Results of measurements of distant sferics indicate rather sharp cutoff frequencies below which broadband, impulsive noise is attenuated. The mechanism of propagation for this noise above the daytime cutoff frequency of 3500 Hz and the nighttime cutoff frequency of 1700 Hz is deduced to be a waveguide formed by the D or F layers of ionosphere as an upper plane and the earth as a lower plane.

Jan 1, 1974

By W. P. Diamond, B. M. Bench, C. M. McCulloch, Maurice Deul

As part of the Bureau of Mines methane control program, the Pittsburgh coalbed was studied in Washington and Green Counties, Pa., and in Marion and Monongalia Counties, W. Va., where this coalbed is now being mined at its greatest depth. The coalbed thickness appeared to be structurally controlled; the bed was generally thinner near the axes of anticlines and thicker near the axes of synclines. The overburden isopach shows a similar relationship. Most of the clay veins in coal occur in the synclinal troughs, generally under sandstone roof. Cleat orientations measured in 18 underground mines showed that face cleats are perpendicular to the axial trends of the folds, and the butt cleats are parallel to the axial trends, indicating structural control of the cleat. Measurement and analysis of surface joint orientations provide a method for predicting the cleat orientations of the coalbed, but linears measured from infrared photographs and photoindex sheets helped only to determine regional trends. The results of these investigations provide a geologic framework for rational planning for underground mine development to use the best available technology to cope with methane emissions, coalbed discontinuities, and related ground support problems.

Jan 1, 1975