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Under the Bureau of Mines Research Contract Number H0252071, Foundation Sciences, Inc. has compared the relative effectiveness of roof bolts installed at an angle over the rib with that of bolts installed vertically at the rib side, The information gathered during this investigation was sufficient to supply supplementary information on the mechanics of roof support systems and the general acceptability of field instrumentation methods. During the 140 days of field investigation, 235 bolts were installed, 45 inclined and 190 vertical, in two adjacent intersections. Of these 235 bolts, 30 were in-stalled with load cells and 38 were tested for anchor capabilities. In addition to this instrumentation, the deformation of the opening was measured by convergence meter on 9 lines throughout the two testing areas, and a borescope and photo-elastic gauges were utilized to obtain information on the roof action beyond the surface.

Jan 1, 1977

By James M. Stuckey

In a search for improved methods of upgrading tar obtained by low-temperature carbonization of coal, monoethanolamine (MEA) was found to be effective in extracting tar acids from coal tar distillates derived from a subbitunwous and a lignite coal. Patch extractions showed that both yield and purity of the extracted acids improved with increasing volume ratios of monoethanolamine to tar acid, varied from 1:4 to 8:1. Yield improved, but purity decreased as the concentration of monoethanolamine was changed from 30 to 70 volume-percent, and as the concentration of tar acid in distillate was increased ad from 14 to 45 percent. In a continuous countercurrent extraction employing a double solvent (monoethanolamine and hexane) approximately 80 percent of the tar acids was extracted from 170° to 350° C. tar distillate when using 1.6:1 volume ratios of amine:tar acids. Tar acids isolated from his extract, although of improved purity, contained appreciable quantities of neutral oils and some tar bases. Aqueous monoethanolamine was not effective for extracting the last 10 to 15 percent of tar acids in 170° to 350° C. distillate oil from lignite coal. The highest yield of isolated tar acids and the best recovery of monoethanolamine were obtained by diluting the extract with water and saturating with C02. Some losses of solvent were encountered when aqueous monoethanolamine solutions were heated through decomposition of the amine with the liberation of ammonia.

Jan 1, 1960

By Blade O. C.

This report is one of a series made by the Bureau of Mines under a cooperative agreement with the Coordinating Fuel and Equipment Research Committee of the Coordinating Research Council, Inc., on the characteristics of commercial aviation gasolines. The series of surveys is a continuation of like work conducted from 1940 to 1946 by the National Bureau of Standards under a similar cooperative agreement. A list of reports of previous surveys is given at the end of this paper.

Jan 1, 1950

By J. R. Thoenen

During 1928 questionnaires covering the calendar year 1927 were sent to over 1700 quarries: producing stone for purposes other thaw cutting to dimension. These inclined producers of stone for limn burning; cement manufacture, rip rag, and crushed stone. The various rinds of stone represented were limestone, trap rock, sandstone, granite, and marble. Replies received from limestone producers prior to November, 1928, were compiled into tables and published in February, 1925, as a preliminary report (Bureau of Mines Report of Investigation 2911).

Jan 1, 1930

By Robert J. Hundhausen, GEORGE M. GRISMER

This circular describes the methods and costs of deepening the Silver Summit three-compartment shaft in the Coeur d'Alene mining region of Idaho. A noteworthy rate of advance was achieved at this operation by the successful use of a mechanical shaft-mucking machine. The Silver Summit mine is 1 mile west from the town of Osburn, Idaho, via U. S. Highway 10. The adit-level portal of the mine is on the south slope of the Coeur d'Alene River Valley at an altitude of 2,700 feet. The Silver Summit shaft is 6,000 feet from the portal. In past years this shaft had been sunk from the adit level to a depth of 1,500 feet. During 1946 the Polaris Mining Co, deepened it to 3,095 feet. The work was done under a co- operative development agreement between the Silver Summit Mining Co. and the Polaris Mining Co.

Jan 1, 1948

Unfortunate occurrences resulting in injuries, loss of life, and destruction of property by explosion, fire, and other mishaps during shaft sinking in the past few years have focused the attention of the Bureau of Mines on the need for safety standards for such operations. Several States have some rules and regulations applicable to local conditions, and several Bureau publications (including some now out of print) cover the hazards that may be encountered in shaft sinking. Certain requirements of the Federal Mine Safety Code and Federal Coal Mine Safety Act may be applied, but there are no definite, uniform standards that will guide those desiring to sink a shaft safely and bring about uniform safety inspections.

Jan 1, 1957

By W. P. Haynes

To evaluate the potential use of battery-powered vehicles, the Bureau of Mines studied the performance of a battery-powered truck propelled by a 9.6 kw dc motor in considerable detail under various driving conditions. Some of the factors investigated were: Gear ratios, payload (1,468 lb maximum), road grade, stops made per mile, and charging time. With the exception of some difficulty with brush wear, operation and maintenance of the truck was generally trouble-free. On range tests carrying an 868-lb payload a distance of about 50 miles at an average speed of about 19 mph in normal driving, the Bureau's battery-powered truck averaged 1.6 to 1.9 miles per ac kwhr input. Stop-and-go tests indicated that prospects for the use of battery-powered trucks in house delivery service within city limits are good; performance of the Bureau truck was sufficiently high for that type of service. The estimated power cost of 2.65 cents per mile while making 10 stops per mile was attractively low from the standpoint of fuel costs.

Jan 1, 1967

By G. Asai

The purpose of this Bureau of Mines investigation was to determine the properties of arc-melted iron-chromium alloys ranging in chromium content from 12 to 50 wt.-pct. Alloys were prepared by consumable-electrode arc melting of electrodes composed of high-purity chromium and high-purity iron. Alloys were fabricated to rod and sheet, and the following data were obtained: Electrical resistivity, hardness, tensile strength, and impact strength at room temperature; and creep-rupture life at 650° C. (1,200° F.). As the chromium content of the annealed alloys varied from 12 to 50 pct., the properties varied as follows: The electrical resistivity increased proportionally from 41 to 53 microhm-cm,; the Rockwell hardness varied from A 38 to A 58; the tensile strength ranged from 52,000 to 96,000 p.s.i.; the impact strength of V-notched charpy specimens varied from 140 to 405 ft.-lb., and the 100-hour creep rupture life at 1,200° F. varied from 5,000 to 16,000 p.s.i.

Jan 1, 1962

By F. H. Nehl

The U.S. Bureau of Mines investigated the selective electrowinning of Ag and Au from cyanide solutions contaminated with Cu with the goal of decreasing the amount of Cu codeposited. Decreasing Cu codeposited will reduce refinery costs. Direct current was applied to the cell in pulsed and square wave voltages at 0.070 A?h per 150 mL of solution. Times tested for each cycle ranged from 1 to 10,000 ms. Graphite, lead, and stainless steel were evaluated as electrode materials. Square wave electrowinning at 70° C gave the best separation of Ag and Au from Cu. Applying 2.5 V during the duty cycle, 0.0 V the rest of the period, a duty cycle of 10 to 30 pct, and a period of 100 to 1,000 ms gave the following results: Ag concentrations decreased from 34 to 0.1µg/mL, Au concentrations decreased from 54 to 0.2 µg/mL, and Cu concentrations remained almost constant at 560 µg/mL.

Jan 1, 2010

By Ralph V. Higgins

The present methods of appraising the long-range performance of oil reservoirs are based upon physical properties of the crude oil and the permeability of the reservoir rock. By means of these methods the performance of a reservoir may be estimated throughout its entire life. Before these methods were used, the future performance was estimated mostly by extrapolating pressure-decline curves -a method that is satisfactory for extrapolating only for a short period into the future. One factor that affects satisfactory long-range prediction of reservoir performance is the extent to which small changes in the physical properties of the oil and differences in the choices of relative permeability influence the calculated oil recovery. Selection of the physical properties of the samples to represent those of the oil and rock for the entire reservoir is difficult. This report is concerned with the error in calculated recoveries that may result from these inherent difficulties.

Jan 1, 1956

By T. W. Johnson

The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past-several years the flow of natural bas through high--pressure pipe lines.4 This report deals with that part of the study involving the design of pipe-line, systems consisting of lines laid parallel to each other. The lines are deferred to as the original line and the parallel line. The paralleling line may or may not extend the entire length of the original line; however, the parallel line is, connected at its two ends to the original line. As a result of the large expansion of the natural-gas industry almost all markets within economic distance from the developed gas fields have at least one pipe line supplying them with natural gas. Small increases in the consumers' demand for natural gas can be met usually by increasing operating pressures, but any marked increase in demand necessitates paralleling sections of the existing systems. It is believed that to a large extent future

Jan 1, 1934

By W. W. Adams

The extent to which coal mines have installed various types of haulage systems and mining machines is a subject about which there is little definite information available in convenient form for the country as a whole . A few State mine inspectors include in their annual reports such information for their respective States , but uniform data for the United States have not until recently been compiled . Several years ago the Bureau of Mines compiled from one of the standard mining directories * a statement showing the kinds of machines and haulage used in coal mines . The first statement was prepared from the 1918 edition of the directory in which detailed descriptions of coal mines were given . The information presumably related to the calendar year 1917. Similar statements have been compiled from the directories for 1919 , 1920 , and 1922 , the statement for 1921 having been omitted because the directory for that year did not become available . The latest statement is given below and is based upon the directory for 1922. It relates to conditions prevailing in 1921 , and covers a total of 7,088 coal mines . Of these , 5,064 mines . or more than 71 per cent , were using animal haulage . As compared with the total number of all classes of mines , those in the animal - haul age group constituted 71.4 per cent , the percentage having remained practically stationary during the past four years , although the actual number of mines in the group has increased . Rope haulage was reported by 1,066 mines , or 15 per cent of the total , representing a larger number of mines than in 1918 , but a decrease of 2 in the percentage for the group as compared with all classes of mines . Electric haulage was reported by 3,274 mines (46.2 per cent ) , and the number of motors in use was 11,265 . The percentage of mines in this class has not changed materially, but the actual number of mines has shown a gain of about 900 during the past four years . Compressed-air locomotives have not increased either in actual or relative number , the percentage for the past year being but 1.2 . The number of mines using storage- battery locomotives has increased from 3.6 per cent of the total shown four years ago , to 9.8 per cent for last year, the latest figures showing 693 mines with 1,428

May 1, 1922

By Daniel G. Di Canio

A computer based accident cost indicator model (ACIM) for estimating tangible costs of occupational injuries, illnesses, and fatalities in the U.S. mining industry is described. Studies performed to expand the scope of the ACIM to all mining sectors are presented. Validation of ACIM cost element estimation algorithms with actual costs of mining-related injuries and illnesses are presented. A study of the effect of a fatal accident on production in surface coal and metal/nonmetal mines is presented. The study is based on a sample of 15 fatalities in underground and surface mines. Evidence of significant long- term decline in postfatality production at 6 of 8 underground samples is presented. The average loss is shown to be 1.8% of annual mine production. A study of accident costs in U.S. mining from 1975 through 1981 using the ACIM is presented. The study shows that total annual costs increased from $180,000,000 in 1975 to $379,000,000 in 1981, a 15% annual increase after adjusting for inflation, with mining companies bearing 45% of the total and expected wage losses to mining families accounting for 42%. The study shows total costs of $12,400 per accident and $674,000 per fatal accident for 1981.

Jan 1, 1983

By D. P. Schlick

As of June 30, 1970, Federal regulations required the operator of each underground coal mine to maintain the average concentration of respirable dust below legislative standards. As of March 1, 1971, over 152,000 respirable dust samples have been processed by the Bureau of Mines. Approximately 75 percent of underground working sections are being sampled in accordance with Federal regulations. Results indicate that 72 percent of the sections which have completed at least one basic sampling cycle are below 3.0 mg/m3, the standard in effect under the Federal Coal Mine Health and Safety Act of 1969 (P.L. 91-173). Notices of Violation were issued on 1,670 underground mines for failure to begin a sampling program; Withdrawal Orders were issued in 64 of these instances. Notices of Violation were issued on 1,121 sections where applicable dust levels were exceeded; Withdrawal Orders were issued in seven of these instances. There are 381 mining sections currently operating on permit; from the interim Compliance Panel.

Jan 1, 1971

By G. W. Jones, R. E. Kennedy

A simple , quick, and relatively accurate device is needed for determining the presence of very small concentrations of organic halide gases in various atmospheres . Such a device would enable safety engineers , health officials , and others to discover quickly the presence of these gases in a suspected atmosphere and thus be able to apply protective measures promptly. This detector should prove useful in detecting leakage of halide gases from refrigerating and air - conditioning systems and in determining the presence of halide solvents in the atmosphere of dry - cleaning and degreasing establishments where organic halide solvents are used . Virtually all poison war gases are halide compounds . Because of the high toxicity of these gases , even in very low concentrations , a detector having the proper sensitivity should be useful in civilian defense for determining when atmospheres are relatively free of poison gases .

Apr 1, 1943

By P. A. Bloom

Bureau of Mines research was conducted to develop effective separation methods that might be used in exploiting substantial tonnages of complex barite-fluorspar ores in Arizona. The exploitable reserves now may be increased as recent batch and continuous flotation tests demonstrated that a complex barite?-fluorspar ore from the Red Chief deposit, Yuma County, Ariz., could be selectively treated to concurrently produce (1) fluorspar and (2) a barite byproduct of marketable grade. The sample contained 24.8 percent CaF2 and 24.3 percent BaS04. Processing comprised production of a fluorspar product containing 97 percent CaF2 with an 82 percent recovery, using a sodium fluoride-lignin sulfonate-fatty acid reagent combination. Concurrent retreatment of the fluorspar tailing, using sodium cetyl sulfate as a collector, yielded a barite product of 94 percent BaS04 grade with a 71-percent recovery. The products met specifications for acid-grade fluorspar and drilling mud-type barite.

Jan 1, 1963

By A. W. Deurbrouck

Five preparation plants employing concentrating tables for washing 3/8- inch to 0 raw coal were tested. Two of the plants were washing Pittsburgh-bed coal, two were washing Pocahontas-bed coal, and one was washing Elkhorn-bed coal. Samples of the feed to and products from the tables were collected over the normal operating shift. These samples were analyzed, and complete performance criteria were determined. The results of this study show that the concentrating table is an effective fine-coal cleaner even when operating at 40 percent over the recommended 10 tons per hour feed rate. Recovery efficiencies for the 3/8-inch to 200- mesh size fraction ranged from 97.3 to 99.3 percent; maximum yield errors and ash errors were 2.4 and 1.0 percent, respectively; probable errors ranged from 0.074 to 0.115 specific gravity units and error areas from 52 to 73 square centimeters. The amount of minus 200-mesh material in the water used for feed water and dressing water to the table had no significant effect on the sharpness of the separation achieved but did have an effect on the ash content of the clean- coal product. In the one plant studied, the substitution of fresh water for plant circulating water reduced the ash content of the clean coal by about 6 percentage points.

Jan 1, 1963

By William H. Lyon

In 1950 the Program Staff of the Department of the Interior undertook an exploratory study in the projection of energy requirements of the nation. This work was reported in Bureau of Mines Information Circular 7582 by H. J. Barnett. In that preliminary study Mr. Barnett, after exploring the nature of the energy economy in some detail, evolved a method for estimating how much energy will be required in the future, based on estimates of trends in efficiency of energy utilization in specific applications, the physical output of specific energy-consuming industries, size of the population, productivity advances in the economy at large, consumer preferences, and other factors. Considerable new information was developed regarding the nature of energy demands and the possible levels of requirements for each fuel under various assumed business conditions. The study analyzed the interrelationships, including substitutions, among the fuels and emphasized the need for viewing the energy economy as an integrated albeit complex whole. This exploratory study showed a need for a single comprehensive statistical re-port that would assemble and show in a uniform manner the diverse published statistical data on energy commodities now scattered through many publications. A particularly important need was for a set of historical statistics showing the production and consumption of all energy on a B.t.u. basis. As the prospective size and nature of the future energy requirements of the nation are matters of continuing importance, this report was prepared to assist further investigations of the subject. In this report the authors undertake to assemble and present in tabular form, on a uniform basis, the production and use of each of the fuels and electric energy in the United states for three census years -1929, 1939, and 1947. The year 1947, rather than a later year, was selected because it is the most recent year for which census data are available showing the consumption of fuel by each of the manufacturing industries. It is hoped that making data for these 3 years available in one re-port will provide the needed statistical background for further studies of fuel requirements and supplies.

Jan 1, 1951

By D. A. Rice

As part of its mission, the U.S. Bureau of Mines continues to develop technologies that will enable cost-effective compliance with environmental requirements. To this end, investigations to improve the kinetics of chalcopyrite dissolution by simultaneous grinding-leaching in ferric sulfate solution were conducted using the Bureau-designed turbo mill. The development of such a hydrometallurgical process would provide a nonpolluting alternative to conventional smelter technology. The effects of mill rotational speed and volume percent solids on the leaching time and energy required for copper extraction from chalcopyrite were evaluated. The results of this laboratory study have shown that the simultaneous grinding-leaching of chalcopyrite concentrate using the turbomill is technically feasible with essentially 100 pet extraction of copper being possible at 90° C. An optimal energy consumption of 1,153 kW?h/st of copper leached was found in batch testing with the mill operating at 400 rpm with a slurry containing 35 vol pet chalcopyrite. This energy consumption, while higher than other proposed leaching processes (about 600 kW?h/st), is of the same order of magnitude. Further refinement of the energy requirements would require additional testing using a continuous circuit. Leaching times of less than 1 h, for 80 pct copper extraction, are achievable using the turbomill grind-leach process.

Jan 1, 2010

By Suresh K. Bhatt

This U.S. Bureau of Mines report reviews major developments in continuous haulage technology for underground coal mines. Haulage systems, both in use and under development, were investigated through a comprehensive literature search and visits to mines and manufacturers. The systems include flexible conveyor train, mobile conveyor, monorail bridge conveyor, multiple-unit continuous haulage, extensible, and belt turning systems. Strengths and weaknesses of the systems are assessed in light of their operating under remote control and their application to the computer-assisted continuous mining machine research being conducted by the Bureau. Through mining scenarios, candidate haulage systems are conceptualized to be consistent with the capabilities of the mining machine.

Jan 1, 1991