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By J. Howard Bird

The purpose of this publication is to describe the power-distribution system of the mine and refinery of the Duval Sulphur & Potash Company at Carlsbad, N. Mex. This distribution system has been excellently predesigned to meet requirements and fit special conditions encountered at the property. In presenting the material, the authors point out various features that would be desirable for incorporation in other systems under similar conditions. Central location of switchgear in pressurized vaults and ventilation of such equipment with filtered air prevent salt accumulations and contribute to trouble-free operation. The simplification of power-distribution circuits and overload protection, as a result of centralization of switchgear, the use of individual control circuits enclosed in conduit (which aids troubleshooting), and central location of control panels, are factors which contribute to efficient, safe operation. Those features are applicable to many operations where fire or explosion hazards are encountered, or where dusty conditions may exist, as well as in operations where numerous individual drives are involved.

Jan 1, 1959

By R. E. Kennedy

"INTRODUCTION In a previous publication4 results were given of numerous experiments made on the in-flammability of gas mixtures consisting of methane, hydro a. carbon monoxide, nitrogen, and carbon dioxide. Data were obtained and tables prepared giving the inflammable limits of each of these combustibles when mixed with various proportions of carbon dioxide and nitrogen. By the use of these data and the application of Le Chatelier's law, it was found possible to calculate the limits of inflammability of any gas mixture containing any or all of the above gases.Various mixtures of the five gases given above were prepared and their limits determined experimentally and then calculated. Good agreement was found between the determined and calculated results when complex gases encountered in mine safety work were tested. Of special significance was the accurate calculation of the limits of inflammability of gases from mine fires, gases from mine explosions, detonation products of explosives, blast—furnace gases, automobile exhaust gas, and other gases of a similar character.Using the method given in the above report, Yeaw5 investigated a number of industrial gases including oven, coal, producer, blue, carbureted blue, and dry quencher gases, and found the determined and calculated results to agree remarkably well, thus giving further proof of the value of such a means of determining dangerous conditions when combustible gases are encountered in practice.GASES FROM A POTASH MINEGases were recently encountered in a potash nine in New Mexico, containing the com-bustibles, methane, hydrogen, and ethane. In one special case a mild explosion occurred when these gases were mixed with the right proportions of air and ignited it therefore became necessary to know the inflammability of these mixtures in order that the proper precautions could be taken to prevent explosions."

May 1, 1932

By J. M. Mutmansky, L. Xu

"This paper outlines the results obtained when sampling twenty underground coal mine sections, each in a different mine. The sampling effort was oriented toward a detailed characterization of coal mine dusts and thus eight-stage Anderson Model 298 impactors were used as the primary collection instrument. This instrument allowed a rather detailed size distribution for each of the particulates sampled. Because four of the mines used diesel outby equipment and/or diesel shuttle cars at the face, it is possible to make some comparisons on the particulate distributions in diesel versus non-diesel mines.One of the more interesting results is the pattern that exists in mines that contain only diesels used for outby utility haulage. Particulate in these mines seem to be consistently heavy in the fine size ranges, perhaps being of significant concern to the industry. While no definite conclusions can be achieved from the limited data collected in this study, the data indicates that more detaile~ study of particulates in diesel mines is needed so that some idea of the particulate loadings in diesel mines can be achieved."

Jan 1, 1988

By R. S. Dean

In general, the Division conducts investigations relating to the treatment of ores and metallurgical products from the condition to which they are mined to the refined metal. At the object of conserving natural resources and eliminating waste by furnishing information on current methods of metallurgical practice making fig fundamental studies of metallurgical processes and developing new processes and alloys to the point of demonstrating their or value. Office of the Chief Engineer The functions of the technical units of the Office of the Chief Engineer are indicates

Jan 1, 1941

By W. W. Adams

Because of insufficient funds for printing, the Bureau of Mines was unable to publish its annual bulletin covering accidents at metal mines in the United States for the year 1933. A brief mimeographed summary of the principal statistical data for that year was released to the public late in 1934. Since then reports for 1934 have been received from the mining companies, and in order to avoid further delay in releasing this information to the mining industry and others interested in the prevention of accidents in mining, statistics for both years are presented in this publication with a minimum of interpretation and comment. The fatal-accident rate for the metal and nonmetallic mines (excluding coal mines) of the United States was more favorable in 1933 than in any previous year since 1911, the first year for which the Bureau of Mines obtained reports from the operators. Further progress was made in 1934, when the fatality rate was even lower than that of 1933. On the other hand, the nonfatal-accident rate, which had reached its lowest level in 1932, increased in 1933 and increased further in 1934, although not to such an extent as to prevent the rate for either of those 2 years from being better than that for any year previous to r1931.

Jan 1, 1936

By Ronald Branstetter

Gaseous and particulate exhaust emissions from 20 diesel engines in service at five underground mines were measured with high accuracy instrumentation. The engines that were tested were checked for faults or maladjustments. The vehicle and engine maintenance organization was studied at each mine and an idealized maintenance program was devised. Faults were induced in a new diesel engine to determine their effect on the characteristics of the exhaust emissions. The results, conclusions and recommendations from this investigation are presented in this final report.

Jan 1, 1983

By S. L. McGill

The U.S. Bureau of Mines has determined the microwave heating rates for a suite of minerals and reagent-grade compounds. Maximum temperature achieved for the samples and the time required to reach temperature are reported. Heating rates of powdered samples are presented as a function of incident powers up to 3,000 W at 2,450 MHz. Descriptions of the microwave cavities, test cells, and a thermocouple assembly used to measure temperature in the microwave field are given. Many minerals of value heated in the microwave field, whereas host rock or gangue materials did not. In general, heating rates increased as incident power was increased. Exceptions to this were some very good (CuO, Fe304, and PbS) and very poor (CaC03 and SiO2) microwave-absorbing materials that showed negligible changes with increased power. Applications demonstrating the use of microwave energy in mineral processing that are described herewith include oxidation-reduction reactions, mineral liberation, and mercury retorting-vaporization. Microwave data on mineral heating rates will provide insight to possible chemical and mineral processing applications as well as assist in predictions of processing parameters.

Jan 1, 2010

By O. C. Blade

Studies on more efficient utilization of petroleum have been made for 50 years by the Bureau of Mines. As part of this work, the Bureau has analyzed thousands of samples of crude oil by its standardized routine method, and many of these analyses have been published, sometimes in special compilations, other times in connection with reports of research on petroleum. This report is a finding index for all analyses published from 1921 to 1959, and brings up to date the information in Information Circular 7470 3 and in the appendix of Bulletin 490.4 The routine method of analysis and the equipment originally were described in a report by Dean and associates. 5 This report has long been out of print, but Bulletin 490, bringing the procedure and its modifications to date, was published in 1951. 6 Briefly, the procedure consists of testing, by standard methods, small samples of a crude oil for gravity, sulfur, color, viscosity, pour point, and (more recently) nitrogen; and, by a standardized procedure, distilling a portion of the crude oil and determining certain properties on the separated fractions and residuum. Careful records are made during the procedure, and the distillation data obtained are used to compute the approximate amounts of products present in the sample--such as percentages of gasoline, kerosine, gas oil, and lubricants. The principal data and results are recorded on a standard analytical report form. An analysis of a sample of crude oil from a recently developed field is shown in table 1. Compilations of these analyses, sometimes in tabular form and usually for specific geographic areas, are published from time to time. Analyses often are included in connection with other studies, such as engineering field reports.

Jan 1, 1959

By R. S. Dean

[In E;encralt the I~8:al:ul',~,C,-J. Div:'sion conducts in\'8stigations relat-ing to the treatment of OrGR o.nd L!\3tallurl..'"lcal prod tctR froJ] t~e condi tion in :hich they are Itinod to t!1e refi!l(,u r.etal, . ' th 'the ob,icct of conserving natmal' resources .e..nd 81:mir..3.tin~ wacte by furn.i:::hir..g :nforInf'_tiou on current methods of metal11:.rgical practice, Tfu'..:.kir..g fund T!l;ntal .;;.otudie'" of metal-lurgical processe~, and de~eloping ~e~ proc6sses O~Q lloys to the point of dewonctrati:r:g the:'..r practicab'lity or va.lue}

Jan 1, 1941

This study estimates costs of producing bituminous coal and lignite by strip-mining methods in 12 hypothetical mines. Basic costs are developed by geographic area, rank of coal, and output capacity. Seam thickness and depth and type of overburden are considered typical for the area in which the hypothetical mine would be located. The cost analyses are based on the use of new equipment, the prevailing union wage scales, and the payment of all miscellaneous costs including royalties, contributions to the miners' welfare fund, and license and permit fees. All model mines are considered to have a life span of 20 years. Capital costs of bituminous strip mines with a capacity of 1 million tons per year range from $12.7 million in the Appalachian region to $16.0 million in the Interior province. The corresponding selling price, assuming a discounted cash flow return of 12 percent on investment, is $5.40 and $6.95 per ton, respectively. For bituminous coal strip mines producing 3 million tons annually, a capital investment of $24.9 million will render a selling price of, $3.46 per ton in the Interior province, whereas a similar mine in the Appalachian region requires a capital investment of $28.0 million to produce coal selling for $4.01 per ton. Subbituminous strip mines of 5 million tons of output per year range in capital costs from $28.7 million in the Southwest to $13.9 million in Wyoming and Montana. Coal produced in the Southwest would sell for $3.03 per ton, while coal from Wyoming and Montana would sell for $1.83 and $1.64 per ton, respectively. The capital costs for the strip mining of lignite range from $6.4 million for an output capacity of 1 million tons annually to $20.7 million for an annual capacity of 5 million tons. The corresponding selling prices of $3.01 and $2.12 per ton, respectively, Indicate the advantages of a large-capacity strip mine.

Jan 1, 1972

By M. Troyer

A coal shuttle car equipped with a pulsed laser optical ranging system to provide guidance for an automatic steering system was tested in production coal mining. Test results are presented for the two mines where testing took place, and some operator's reactions are included. Automatic steering control keeps the car cantered in an entry, and automatic turns are made at intersections as signaled by the operator. All other controls-tram, conveyor, brake, etc, remain manual and require operator control. Complete override of steering while in the automatic mode is retained by the operator, who may grab the steering wheel at any time and turn in opposition to the automatic signal by applying about 10 foot-pounds of torque.

Jan 1, 1976

MFIRE is a computer simulation program that performs normal ventilation network planning calculations, and dynamic transient state simulation of ventilation networks under a variety of conditions. The program is useful for the analysis of ventilation networks under thermal and mechanical influence. MFIRE simulates a mine's ventilation system and its response to altered ventilation parameters, external influences such as temperatures, and internal influences such as fires. Extensive output enables detailed quantitative analysis of the effects of the proposed alteration to the ventilation system Network simulation using digital computers has become widespread throughout the mining industry in recent years. However, as the sophistication of the simulator increases (MFIRE, for example), the complexity of input data requirements and interpretations of results requires more skill and knowledge from the users. Perhaps the most difficult part of using MFIRE is to construct the data set describing the mine's physical layout and its ventilation properties. The initial attempts to get the data set running often reveal unknown or ignored aspects of the mine's ventilation. MFIRE was written in Fortran 77 and compiled with Microway1 Fortran for the Intel 80386 based computers with a 80387 math co-processor. The source code is portable and available for users who wish to modify the source code to operate on other computers. This user manual describes the development of MFIRE, the input format and requirements, the output, common errors, fire parameters, and examples MFIRE application. Valuable reference material is included in the appendices. Knowledgeable users may skip directly to the PROGRAM INSTALLATION AND OPERATION section to begin using MFIRE immediately.

Jan 1, 1995

By V. R. Spironello

The Bureau of Mines is conducting studies of the slags related to ferrous technology to evaluate acceptable substitutes for the auxiliary flux, mineral fluorspar, in foundry operations. This work is directed toward the Bureau's goal of minimizing the Nation's dependence on scarce and critical minerals Comparative basic practice cupola (18-inch-ID) trials were made to evaluate a waste material called "used potlining," which contains significant levels of fluorine, sodium, and aluminum in various compounds. Used potlining is recovered from alumina reduction cells after its useful life, and was supplied by the Aluminum Co. of America (Alcoa) to the Bureau for evaluation. The material in the lump and pelletized form (with limestone) provided extremely fluid slags based on visual observation during cupola operation. No adverse effects were found on cupola performance, metal and slag chemistry, the environment, or mechanical properties of the castings produced. Fluorine recovery in the slag was equal to, or higher than, that of fluorspar; fluorine losses to the scrubber water and solids were lower. The acidity of the scrubber Hater was somewhat neutralized. No difference was observed in furnace-refractory attack, as determined by the level of magnesia in the slag and visual inspection. The recovery of sodium in the slag, presumably as the oxide, significantly increased slag fluidity, suggesting that less than equivalent fluorine may be required. There was no contamination of the gray iron by the aluminum from the used potlining. Used potlining was completely satisfactory as a substitute for fluorspar in cupola ironmelting.

Jan 1, 1981

By D. S. Burgess

About 100 tests of flammability were carried out with H2, CH4, and CO in mixtures with air using the Federal Bureau of Mines 12-ft-diameter spherical pressure vessel as an explosion test chamber. The LeChatelier approximation gave slightly conservative estimates of the limits of downward flame propagation (onset of significant pressure rise) using the following measured values for the individual gases, in percent: H2, 8.5; CH4, 5.25; CO, 13.0. No justification could be offered for using the LeChatelier law for upward flame propagation limits and indeed reported data suggest that calculated values would not be conservative. The observed upward limit for methane-air mixtures (4.85 pct) was less than the widely accepted lean limit for this fuel; those for lean hydrogen-air mixtures and carbon monoxide-air mixtures did not differ from the lowest accepted values. Diffusional effects on the propagation of single, binary, and ternary fuel mixtures are discussed.

Jan 1, 1982

By Eugene T. Sheridan

The Bureau of Mines annually canvasses the peat producers in the United states and publishes economic data on the peat industry, based upon reports submitted by producers. This publication lists all producers that reported commercial production to the Bureau for 1960 and presents data on individual plants. The companies named herein represent virtually all commercial producers, although a few small companies may not have been canvassed as the industry has many small operations that operate intermittently. Output of the various companies listed ranged from a few tons to more than 50,000 tons. Peat is included in the Bureau's annual surveys of the mineral industries because peat is classified as a mineral fuel. Although none is used for fuel in the United States, peat is a potential source of energy and ranks as one of our large mineral resources. The domestic peat industry sells peat, chiefly, for use as a soil amendment for general soil-improvement purposes. During the past decade the industry has expanded rapidly with operations increasing from 45 in 1947-494/ to 115 in 1960. Output during this period has more than tripled, increasing from 131,782 short tons to 470,889 short tons.

Jan 1, 1961

By E. G. Davis

This report summarizes an investigation to determine the occurrence and recoverability of heavy minerals in sand and gravel operations in the Southeastern United States. A total of 61 samples from 34 sand and gravel operations in Alabama, Georgia, South Carolina, and North Carolina were studied. Heavy minerals, in amounts ranging from 3 to 400 pounds per ton, were found in all of the samples. Eighty percent of the samples contained 20 to 40 pounds per ton of heavy min¬eral. Valuable heavy minerals, in order of decreasing amounts, were ilmenite, kyanite, zircon, rutile, and monazite. Large-scale concentration tests were made on five samples from four major producers. Gravity concentration by Humphreys spirals and tables resulted in bulk heavy mineral concentrates that graded from 82 to 98 percent total heavy minerals. Mineral recoveries ranged, in percent, as follows: Ilmenite 60 to 95; zircon 96 to 100; kyanite 37 to 77; rutile 89 to 100; and monazite 96 to 100. Separation studies on the gravity concentrates showed they would respond to high-tension and high-intensity magnetic separation techniques to produce individual mineral concentrates. The recovery of each individual mineral from fractionation of the heavy mineral gravity concentrates, in percent, was: Ilmenite 77 to 94; rutile 41 to 68; kyanite 62 to 79; zircon 49 to 83; and rare-earth products, monazite and xenotime, 42 to 96. The grade of each mineral concentrate was: Ilmenite 51.1 to 68.7 percent Ti02; rutile 93.7 to 94.3 percent Ti02; kyanite 55 percent A1203; zircon 58 to 61 percent Zr02; and rare-earth products containing 73.8 to 90.8 percent monazite and 4.8 to 12.7 percent xenotime.

Jan 1, 1971

By D. N. Nilsen

A mathematical modeling method was developed by the Bureau of Mines for the prediction of the principal equilibrium species in the solvent extraction of copper. The use of models for predicting the amount of metal extracted can reduce the amount of experimental work required to characterize a system for purposes such as optimization studies. Models were developed for the extraction of copper from ammoniacal sulfate and carbonate solutions with commercially available extract ants commonly used by industry. Results from laboratory shakeout tests compared well with predictions of the equilibrium concentrations of copper and pH values. For example, the loading of copper onto the solvent was predicted for most cases within ±S pct of the measured values, and the pH to with-in ±O.l pH unit in sulfate systems and ±O.2 pH unit in carbonate systems. Both mechanistic and empirical extraction equations were developed from laboratory data for copper and ammonia. The empirical-based models were slightly more accurate than were the mechanistic-based mod-els. Industrial level concentrations of the aqueous and organic constituents were used in this work. Independent variables included copper concentration, ionic strength, and initial pH of the aqueous phase; extractants, diluents, and their concentration in the organic phase; and temperature.

Jan 1, 1988

Mining activity during 1977 was limited to the production of limestone, marl, and sand and gravel, all of which were used domestically. Public works projects consumed the major portion of the construction material produced. The consortium of oil companies operating as Esso Ventures Inc., drilled one exploratory well off the coast of southern Belize. For drilling the well, Exxon Corp. received a 57% working interest in the consortium's concession located 40 kilometers east of Puta Gorda. No other offshore drilling was attempted in 1977. Esso also drilled a well on the Anschutz Overseas Inc. concession in the Toledo District of south- eastern Belize. The attempt wee abandoned, but seismic activities continued.

Jan 1, 1981

By James E. Cairelli

The NASA Lewis Research Center, under U.S. Bureau of Mines program direction, performed an assessment of alternative mobile power sources for mining applications. A wide variety of heat engines and energy systems was initially examined to ascertain which could be considered as potential alternatives to presently used power systems. The present mobile power systems are electrical trailing cable, electrical battery, and diesel - with diesel being largely limited in the United States to noncoal mines. Each candidate power source was evaluated in terms, of the following requirements: (1) Ability to achieve the duty cycle (2) Ability to meet Government regulations (MSHA certification) (3) Availability (production readiness) (4) Market availability (5) Packaging capability An initial screening reduced the list of candidates to the following: (1) Diesel (2) Stirling (3) Gas turbine (4) Rankine (steam) (5) Advanced electric (batteries) (6) Mechanical energy storage (flywheel) (7) Use of hydrogen evolved from metal hydrides This list of candidates was divided into two classes of alternative power sources for mining applications - heat engines and energy storage systems. A summary of each class follows.

Jan 1, 1981

By W. C. Babcock

This report covers Phase V of .a continuing program to apply a new liquid membrane process called coupled transport to the recovery pf metals from hydrometallurgical leach solutions. During this phase of the program, a membrane system of moderate scale was constructed and field-tested at the Exxon Highlands Mine and Mill Co. site near Douglas, Wyoming. The test unit contained four hollow-fiber membrane modules, each with 100 ft2 of membrane area. In the field tests, about 1000 gallons per day of leach solution was processed. The unit was operated on the leach solution for about 50 days. Leach solution entering the unit contained 100 ppm uranium. This concentration was reduced to about 5 ppm by coupled-transport treatment, and the uranium was concentrated to about 2 wt% as a uranyl carbonate product. Under these conditions, a transmembrane uranium flux of about 2.5 lb/ft2-year was obtained. An economic analysis showed that the cost of recovering uranium from this leach solution via coupled trans-port is about $1.20/lb. At higher concentrations of uranium in the leach solution this cost is reduced. For example, at 1000 ppm the cost of uranium recovery is about $0.30/lb.

Jan 1, 1983