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By Seth C. Schaefer

The Bureau of Mines investigated the thermodynamic properties of Bi203 (bismuth sesquioxide) and Sn02 (stannic oxide). Standard Gibbs energies of formation (AGfO) of these compounds were determined with high-temperature electromotive force (emf) cells using stabilized Zr02 (zirconia) as the electrolyte. Potential measurements were obtained from the cell

Jan 1, 1984

By Michael Rieber

An analysis of coal slurry pipelines was presented in our May 1976 study, Route Specific Cost Comparisons: Unit Trains, Coal Slurry Pipelines and Extra High Voltage Transmission (4]. The present study extends that analysis. The earlier work included technical and economic cost descriptions of the black Mesa and ETSI pipelines as well as some hypothetical pipeline routes. Water problems, safety and environment, required resources, and labor impacts were discussed at some length. Additionally, pipeline impacts on competing railroads, slurry-rail comparisons, and cost escalation. were analyzed. The difference in pipeline profitability to an owner-operator versus a promoter-builder was suggested. These aspects are not redone in this study. Here, we present a synopsis of the previous results and a general statement of coal slurry pipelines. Extensions of the arguments are presented where they appear warranted. New material is developed in the area of pipeline branching and tapping. This would appear necessary if slurry pipelines are to function as more than private lines; if they are, for example, to be responsive to common carrier requirements.

Jan 1, 1977

By Michael J. Bertoldi

The purpose of this Bureau of Mines report is to describe the methods and establish the basic economics for dragline, shovel-truck, and scraper mining systems. An overall view of the techniques of preliminary design and the cost involved is presented. Considerations of equipment selection, emphasizing short-range evaluation of required equipment, and a long-range evaluation are considered at a constant production rate over the life of a hypothetical mine. Separate cost analyses for each system were based on 1977 equipment prices, prevailing wage rates, and associated mining costs. Specific engineering and cost breakdown for such items as access roads, transmission line installation, rail spurs, etc., are beyond the scope of this report.

Jan 1, 1977

"To prevent the propagation of mine explosions, the Bureau of Mines recommends:1. That all coal and lignite mines, except anthracite mines shall be rock dusted.2. That rock dust shall be distributed upon top, bottom, and sides of all underground openings of every description, to within. at least 4o feet of all working faces and the areas not rock dusted shall be kept wet.3. That the rock dust shall be maintained in, such quantity that the incombustible material in representative samples of dust collected shall not be less than 65 percent. Where methane gas is present in the ventilating current, the minimum percentage of incombustible matter in the mine dust shall be increased 1 percent for each 0.1 percent of methane.4. That when the rock dust in any area becomes caked so thatit cannot be dispersed readily as a cloud in the air, that part of the mine shall be redusted immediately.5. That the dust to be used shall not contain more than 5 percent of combustible matter nor. more than 25 percent of quartz or free silica; all of the dust shall pass through a sieve having 20 meshes per linear inch and 60 percent or more shall pass through a sieve having 200 meshes per linear inch; the dust shall not absorb moisture from the air to such an extent as to cake and destroy its effectiveness as a dry dust.6. That rock-dust barriers shall not be regarded as a substitute for generalized rock dusting.Research and experience have shown that maintenance of an adequate percentage of rock dust in all underground openings, whether gassy or not, of bituminous and subbituminous coal and lignite mines (anthracite dust does not propagate explosions) is the best means of preventing coal dust explosions. In rare instances where all fine coal particles on the floor, ribs, roof, and timbers are in a muddy condition continuously rock dusting is unnecessary.The term ""underground openings"" refers to all unsealed openings whether they contain track or not, and includes rooms, entries, crosscuts, breakthroughs, rock tunnels, slopes, haulageways, airways, and travelingways. The sealing of unused or abandoned parts of a mine in accordance with Mine Safety Board Decision avoids the necessity of rock-dusting the sealed-off openings.The kind of rock dust to be used should have the approval of the State Mine Inspection Service. Pure limestone or pare dolomite produces the best rock dust, as these dusts have low silica content, little tendency to cake, and a light color that aids illumination. To reduce tendency to cake it is preferable that not more than 75 percent of the dust pass the 200-mesh sieve. All sieve sizes are those of the Tyler screen scale. If the mine personnel is repeatedly exposed to breathing high concentrations of the dust, the percentage of free and combined silica should be as low as possible, preferably less than 5 percent. Persons engaged in the application of rock dust should wear approved dust respirators as listed in Bureau of Mines Information Circular 7030 or revisions thereof."

Mar 1, 1940

By Frederick C. Tompkins

A complete service system was established for the monitoring of personnel exposure to N02 based upon the use of passive dosimetry. This system is structured such that minimum effort is required of the user: manufacturing, analysis, reporting, and record keeping functions are provided by the service organization. A field evaluation program was carried out in a dieselized mine to assess the performance of two passive dosimeters, the Walden GASBADGE TM dosimeter, and a tubular dosimeter developed at New York University. Side-by-side comparisons were carried out to evaluate dosimeter suitability for monitoring in the field, and to assess relative accuracy characteristics.

Jan 1, 1976

By Roger J. Morrell

Bureau of Mines laboratory experiments with reduced scale cutter and cutter forces were performed to (1) define the fundamental relationships governing disk cutter performance and (2) to develop a method of predicting disk cutter performance in soft, medium, and hard rocks. The rock cutting experiments were performed in four igneous and metamorphic rocks that ranged in compressive strength from 38,000 to 67,000 psi. A special testing machine called a linear cutter apparatus (LCA) was used to load and traverse a free rolling disk cutter across a smooth rock surface. Each pass of the disk produced a single crater, and runs were spaced to avoid breakage between craters. During each run the normal and tangential cutter forces were measured and recorded. The soft and medium rock data were obtained from previous Bureau experiments with disk cutters. Crater depth, tangential cutter force, crater volume, specific energy versus normal cutter force, and crater width versus depth are defined within this study. With the use of standard physical properties, performance prediction equations were developed using stepwise linear regression analysis techniques. A method of using these prediction equations to calculate the boring rate, the cutter spacing, and the torque and energy requirements of a full-scale boring machine was also developed.

Jan 1, 1974

By Jr. Sayre

Results of studies of reservoir and wax-precipitation temperatures relating to wax deposition in the reservoir of the Bradford oil field are presented in this report. During 1949 and 1950 Bureau of Mines engineers made temperature measurements in 42 wells, which indicate that the Bradford Third-sand temperatures range from 59.7° F., at 1,150 feet, to 71.9° F., at 2,040 feet. Reservoir temperatures measured at the same depths in newly drilled wells and oil-producing wells differed as much as 4.5u F. Injection-well temperatures measured during water injection showed that the temperature of the water entering the sand was 11.5° F. lower than reservoir temperatures before injection. The cooling in the formation resulting froth the injection of low-temperature water was 11.5° F. in the vicinity of the injection-well bore, and a maximum of 2.1° F. 200 feet from the injection well. Sand temperature, after 5 months of water injection, was reduced 1.5° F. 90 feet from water-injection wells. The temperature at which wax begins to precipitate from solution in crude oil was determined at atmospheric pressure for 26 samples and ranged from 51° to 67° F. Oil samples from wells producing no water had wax-precipitation temperatures ranging from 51° to 58° F. and wax contents from 2.20 to 2.97 weight percent, whereas the samples from wells producing water and oil had wax precipitation temperatures ranging from 580 to 67° F. and wax contents from 2.57 to 3.42 weight percent .

Jan 1, 1952

By W. W. Adams

Increased employment and a lower accident-frequency rate were the outstanding features of the metal- and nonmetal-mining4 industries of the United States in 1939 compared with 1933, according to reports furnished by individual mining companies to the Bureau of Vines, United States Department of the Interior. Except for 1937, the reports for 1939 showed gains both in number of employees and number of mar -hours worked over all years since 1929. The accident-frequency rate per million man-hours of exposure to mining hazards was lower than in any year since 1925. Reports for 1939 revealed a total of 111,909 men employed in and about mines, an increase of inure than 8 percent over 1931 The total volume of labor performed at all mires was slightly more than 299 million plan-hours, an increase of mare than 10 percent over 1938. As these gains suggest, the average employee had a longer period of work in 1939, the increase amounting to r workdays per employee.

Jan 1, 1941

By William K. Cunningham

The investigation described in this report was begun as part of the Bureau of Mines progress to develop acid processes for the extraction of alumina from low-grade bauxite and. clays. A domestic shortage of high-grade bauxite sui table for treatment by the Bayer process became acute as a result of' World War II; an intensive search for a practical acid process using lower-grade alumina-bearing raw materials was therefore warranted. The laboratory development was described in a preceding Bureau of Mines publication wherein the basic theory for the design and erection of a pilot plant maybe found. A 2-ton-per-day continuous pilot plant was constructed and successfully operated at College Park, Md., which demonstrated conclusively the chemical and mechanical feasibility of a solvent purification process for aluminum sulfate. The estimated production cost of $38.64 indicates that under present market conditions the process would not be economically feasible.

Jan 1, 1948

By M. J. Ferrante

Laboratory-scale tests were undertaken to examine several electrolytes for possible use in separating nickel and cobalt from products being prepared at Nicaro, Cuba. The most extensive work was done with nickel sulfate-ammonium fluoride, ammonium fluoride, ammonium sulfate, and nickel sulfate-boric acid electrolytes. All four electrolytes exhibited some selectivity for dissolving nickel carbonate from Nicaro basic carbonate used for regeneration. The nickel sulfate-ammonium fluoride electrolyte exhibited less selectivity for dissolving nickel carbonate from Nicaro basic carbonate than it did from synthetic mixtures. Ammonium fluoride leaching experiments showed that a low concentration and high temperature gave a good nickel extraction with C. P. reagents; however, this was not confirmed in tests using Nicaro basic carbonate. Electrolytic tests employing ammonium fluoride leach liquors gave no further separation, since approximately 90 percent of the cobalt was deposited at the cathode with the nickel.

Jan 1, 1958

By D. Randolph Berry

Volume II contains appendices which explain and document the recommendations of Volume I. The following topics are covered: Appendix A Discussion of Recommended Guidelines Appendix B Worldwide Use of Oxygen Self-Rescuers Appendix C Hypothetical Use of Oxygen Self-Rescuers in Post-1972 Coal Mine Explosions and Fires Appendix D Vibration Testing of SCSRs Appendix E Testing of In-Service Chemical Oxygen SCSRs Appendix F Discussions with Representatives of Underground Coal Mining Appendix G Recommendations for SCSR Storage Containers Appendix H Example SCSR Storage Plans Appendix I Testing of In-Service Compressed Oxygen SCSRs Appendix J 30 CFR 75.1714, 30 Regulations Pertaining to Self-Rescuers

Jan 1, 1981

By John C. Machisak

INJURY and employment figures for nonmetal mines and mills in 1959 are presented in this publication. Data for nonmetal mines are presented separately from those for nonmetal mills. The Bureau of Mines is authorized to send questionnaires to the nonmetal mining industry each year requesting their voluntary submission of injury experience and employment data. The voluntary response to these requests has contributed greatly toward the promotion of safety in the industry, and every effort has been made to make the information as complete as possible.

Jan 1, 1963

By A. G. Mayton

Vehicle vibration exposure has been linked to chronic back pain and low back symptoms among agricultural tractor drivers. The objectives of this study by the National Institute for Occupational Safety and Health (NIOSH) were to assess driver whole body vibration (WBV) exposures and recommend interventions to reduce the risk of back related injuries, particularly relative to vehicle jarring/jolting (the transient mechanical shock components of WBV). The methodology included collecting, from two independent samples, ?eld data and health and work history data of farm equipment operators. Data were collected during mowing, raking, baling, chiseling, tilling, and road travel for different model tractors. Spraying using a sprayer and shrub removal with a skid steer loader were also included. Based on ISO 2631 (1985), the American Conference of Governmental Industrial Hygienists, threshold limit values, presents 0.5 m/s2 as the action level recommended by the Commission of European Communities for overall weighted total RMS acceleration (vector sum for axes x, y, and z) [ACGIH, 2006. Threshold limit values and biological exposure indices. Cincinnati, OH]. WBV measured at the operator/seat interface exceeded this action level. The roughest rides and highest vector sum accelerations occurred with small utility tractor mowers (3.3 and 2.8 m/s2) and a skid steer loader (1.7 m/s2). Major ?ndings from health and work history data showed 96% of participants reported having to bend or twist their necks, although 24% reported neck symptoms. Sixty four percent of participating operators reported experiencing back symptoms (e.g., pain, aching, stiffness, etc.). Recommendations included: specifying a seat that ??better?? isolates operators from jars/jolts with new tractor purchases; maintaining the seat/seat suspension and replacing worn or damaged cushions with NIOSH tested viscoelastic foam padding; using larger diameter tires with radial ply instead of bias ply construction, particularly on small utility tractor mowers, to aid in attenuating ride ??roughness??; using a swivel seat to reduce the stress on the neck from bending or twisting; and improving efforts to educate owner/operators of the adverse effects of WBV exposures. Since the data presented in this paper were collected from two independent samples, the authors were unable to draw any correlations or etiological inferences from the study. However, results were compared and contrasted with other studies which included similar vibration measurements in agriculture.

Jan 1, 2008

By L. C. Brichta

The Tri-State zinc-lead catalog, compilation of which was initiated by the Bureau of Mines in August 1949, is designed to provide a continuing record of avail-able drill-hole logs and maps of mine developments in the zinc-lead district in southwestern Missouri, southeastern Kansas, and northeastern Oklahoma. The maps and data thus preserved constitute a reservoir of factual information readily available to individuals and firms interested in planning mineral explorations, to Government agencies for formulating estimates or ore reserves, and to the mining industry in the district for general uses. The areas to be included in the catalog embrace the explored and mined tracts within 760,000 acres of the more active western part of the district. The consensus among local mine operators, geologists, and mining engineers is that over 100,000 boles, costing more than $30,000,000, have been drilled in the district. Records of some of the early drilling and mine developments are destroyed or lost, but the Bureau of Mines has copies of about 47,500 drill-hole logs and is accumulating and recording on microfilm those that are currently available. As of May 1, 1954, the logs of approximately 28,000 drill holes had been microfilmed and are available for inspection at the Bureau of Mines office, Joplin, Mo.

Jan 1, 1955

By Keith L. Harris

The performance of the world economy improved significantly in 1984. Real world output!/ grew 4.3% (compared with 2.6% in 19831, the highest since the 4.4% increase recorded in 1978 (table 1). The output of industrial nations rose 4.9%, while that of the developing nations rose 3.7%. The United States and Japan had the largest increases in output of the major industrial nations, with respective increases of 6.8% and 5.8% (table 2). The components of real output with the most significant growth in the industrial countries were gross fixed investment (9.2%), consumer expenditure (3.1%), and public consumption (2.5%) (table 1). Industrial output, as measured by industrial production indices, has returned to about the 1980 level for most of the major industrial nations (table 2). Exceptions to this were industrial production in Japan and the United States; Japan's industrial production rose steadily throughout the 5-yr period and is now more than 16% above the 1980 level, and the industrial production index for the United States reached 11 1.2 (1980=100.0). Real total domestic demand grew at 8.7% in the United States, more than double the rate of Japan, which, at 4.0%, had the second-largest growth. Average demand for all industrial countries was up 5.1%. During 1984 the U.S. dollar showed great strength on international markets, contributing to large current-dollar negative net exports of goods and services and even larger negative net exports of the merchandise sector. While growing U.S. imports helped spread the benefits of the recovery, they also led to a widening of current account imbalances and growing trade tensions throughout the world.3/, 4/

Jan 1, 1985

By I. D. Schleicher, L. H. Rorden, F. B. Curry, T. C. Moore

The purpose of this program is to extend electromagnetic (EM) techniques for use in locating miners trapped in mines as deep as 1000 m. A previously developed EM system is considered adequate for use at mines less than 300 m deep where it has a probability of detection of 54%. A system for deep mines must keep underground equipment simple, and use extremely low frequencies (ELF), sensitive receivers, and noise cancellation. The proposed location method, developed by Develco for other applications, is based on vector field measurements from two or more static sensors and computation of source location by iterative techniques. During Phase II, very sensitive search coil sensors were built and used in a separate test to verify the feasibility of atmospheric noise cancellation. A "Breadboard" location system version without cancellation, which is a fieldable test bed to evaluate receiving and location functions, was tested and supplied. Very good results were achieved from the first in-mine test with the transmitter at a depth of 380 m. It is expected the results of this work, and additional evaluation tests in the future, will be used to define the requirements for a prototype operational system.

By J. P. Rider

Operating practices and resulting production from longwall faces are continually improving. Consequently, longwall operators are continually seeking to improve the dust control capabilities on longwalls. The National Institute for Occupational Safety and Health (NIOSH) has been conducting dust surveys at longwalls throughout the country in an effort to document the types of controls that are being used and to quantify the relative effectiveness of these controls. To date, surveys have been completed at longwalls in Alabama, Colorado, Pennsylvania, Utah, and West Virginia. In addition NIOSH has been reviewing longwall dust parameters provided by mine operators to MSHA to assess the status of dust control technology being used throughout the industry. Results from the underground dust surveys and information obtained from MSHA will be summarized in this paper to provide an update on longwall dust control technology and practices.

By B. W. Gandrud

The upper part of the Alabama deposits of crystalline graphite consists of an oxidized ore derived from the underlying unoxidized ore through prolonged Weathering. The degree of oxidation in different sections and at different depths within the bed is not uniform. The original ore is hard and blue-gray; the weathered product is soft and brown and is the only part that has been mined to any extent. Samples of both oxidized and unoxidized ores were obtained from two of the large graphite deposits of Clay County. Three additional samples of oxidized ore were obtained from different portions of a third property in the same region. In this report, ores 1 to 5 are of oxidized material and ores 6 and 7 of unoxidized.

Jan 1, 1934

By Martin H. Stanczyk

Bench scale, laboratory batch attrition grinding tests were made of a coarse commercial kaolin in a stainless steel, 5-inch-diameter attrition grinding machine to study the effect of a number of basic operating variables on particle size reduction and electric energy consumption. The results of the investigation showed that the more important operating variables influencing the efficiency of kaolin comminution and energy consumption requirements were type, size, and shape of grinding media, grinding media to clay weight ratio, peripheral rotor speed, clay slip pulp density, degree of pulp dispersion, and the angular arrangement of the rotor and stator bars. The tests also indicated that variables having less influence on grinding efficiency and energy consumption were pulp temperature, design of rotor cage, rotor clearance, rotor-stator bar interval, addition agents, pulp level, degree of pulp aeration, and chamber liners. The research showed that grinding media had the greatest influence on abrasion of machine parts and that spherical-shaped grinding media were superior to sharp angular or long bladed media with respect to media degradation, machine abrasion as well as grinding efficiency.

Jan 1, 1968

By Wilbert T. Malenka

A modified factorial experiment was used to determine the effect of operating factors in hydraulic mining of anthracite. Seven basic factors at various levels were considered. The significant factors were found to be pressure-volume, pattern, and jet traverse speed. Mining data were programed for computer, and a prediction equation was determined from printout information based on the hydraulic "jumbo" operating parameters and characteristics of anthracite, The source of error is discussed. The prediction equation is general in nature and might be useful in delineating performance characteristics in the design of equipment and/or more effective utilization in a medium with characteristics similar to those of anthracite.

Jan 1, 1968