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By J. J. Pfeiffer, J. W. Myers, A. A. Orning

A study was made of the feasibility of using washery refuse in the manufacture of lightweight aggregate for building materials . Preliminary caking and burning tests showed that the refuse could be converted into lightweight aggregate but that refuse passing a No. 14 U.S. Standard screen could not be used without additional processing . The aggregate was prepared by pelletizing the refuse and burning out the carbonaceous material on a chain- grate in a refractory - lined furnace . A small stationary - grate furnace was used to study the process variables involved and establish optimum ignition and combustion conditions . Maximum ignition rates were obtained at air rates of approximately 200 lb per sq ft hr , but air rates of 450 or higher were required in the burnout period to obtain temperatures high enough to sinter the ash . The data obtained from this unit were used as a guide in the operation of the chain- grate furnace . In the chain - grate furnace , satisfactory results were obtained by using primary air rates of 200 lb per sq ft hr in the ignition zone and 500 lb per sq ft hr in the burnout zone . The ignition- zone air was preheated to 500 ° F , but the air for burnout was not preheated . A total of 2-1/2 tons of aggregate was prepared in this unit and made into experimental block . A commercial development based upon the results of this study yielded a product which met the ASTM specifications C 130-42 for lightweight aggregate , and blocks made from the aggregate were of good color , durable , and light - inweight .

Jan 1, 1964

The concept of isokinetic measurement of strength was originally related by Hislop and Perrine.(1)Characteristics of an isokinetic exertion are constant velocity throughout a predetermined range of motion. Strictly speaking, a means of speed control, and not a load in the usual sense, is applied in isokinetic exertions.(1)However, load and resistance are definitely present in this technique. In this case, the load is a result of the energy absorption process performed by the device to keep the exertion speed constant. The device prevents energy from being dissipated through acceleration in isokinetic exercise. The energy is instead converted into a resistive force, which varies in relation to the efficiency of the skeletal muscle. Since the speed of motion is held constant in isokinetic exercise, the resistance experienced during a contraction is equivalent to the force applied throughout the range of motion. For this reason, the technique of isokinetic exercise has sometimes been referred to as accommodating resistance exercise. This type of exercise allows the muscle to contract at its maximum capability a tall points throughout the range of motion. At the extremes of the range of motion of a joint, the muscle has the least mechanical advantage, and the resistance offered by the machine is correspondingly lower. Similarly, as the muscle reaches its optimal mechanical advantage, the resistance of the machine increases proportionally. It must be understood, however, that while isokinetic devices control the speed of the exertion, this does not assure a constant speed of muscle contraction. The speed of isokinetic contractions is constant during individual exertions; however, it is also possible to compare muscular performance over a wide range of isokinetic velocities. Increasing the isokinetic speed of contraction will place increasing demands on Type II muscle fibers (fast twitch and fast oxidative glycolytic). Workplace Assessment It is clear that isometric strength testing cannot substitute for dynamic strength assessment when examining highly dynamic occupational job demands. As most industrial work tasks contain a significant dynamic component, analysis of isokinetic strength capabilities appears to offer some advantage to isometric testing in this regard. However, it must be recognized that isokinetic devices are not entirely realistic compared with free dynamic lifting in which subjects may use rapid acceleration to gain a weight-lifting advantage.

Jan 1, 1998

By Wilbur L. Webb

This publication reports on the design, fabrication and test of an Improved methane monitor system for compliance to 30CFR75.313. The system will Initiate automatic shutdown of mining machinery when excessive concentrations of methane are encountered. The prime consideration: In the design were small size, Improved accuracy and reliability, fast response and a transient resistant power supply capable of reliable operation from any mine power source. The power supply contains an internal battery that provides operating power to the detection system prior to mining machine start-up or after machine shutdown. This report documents the development program from conception through in-mine testing.

Jan 1, 1978

The original manuscript of section 2 of this series of miners' circulars devoted to accident prevention in bituminous-coal mines was completed in September 1944. At that time roof bolting had been tried with some success in the lead-mining district of south-eastern Missouri, but information on the subject was so fragmentary that it was not included as a method of roof support. References to roof support in bituminous-coal mines, therefore, were confined almost entirely to conventional timbering methods. In 1947 the Bureau instituted a research program and intensive study of the general problem of roof control, which emphasized roof-bolt application. The rapid increase in mechanized mining following the close of World War II provided the impetus for the Bureau's roof-control investigations, because the vertical supports used with conventional timber restricted the maneuverability of mechanical face equipment, and the industry wanted to explore every possible method of eliminating interference with the production cycle to gain full advantage of mechanized mining. Moreover, the accidental dislodgment of vertical supports greatly increased the roof-fall hazard. As roof falls have killed and seriously injured more mine workmen every year than any other cause or classification of injury since records have been kept, the Bureau assumed this investigative leadership with the prime objective of substantially reducing the annual toll from falls of roof, including falls of rib and face.

Jan 1, 1958

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the fourteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned & name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled except the deep holes drilled to test geophysical anomalies. The locations of those holes are shown on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By Slavoljub Makslmovic

One important element of the U.S. Bureau of Mines computer-assisted mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include use of natural gamma radiation (NGR), vibration, passive infrared, video, and radar. To help establish which CID sensor technologies need to be developed for a given seam, the Bureau has collected geological and mining practices data from over 460 underground and surface mines in the United States. Also, over 500 coal and rock samples have been obtained for laboratory analyses of ash content, sulfur content, heating value, and NGR. The Bureau's findings indicate that the immediate roof strata in 81% of the underground mines and 93% of the surface mines are made up of shale, draw slate, or claystone. The immediate floor strata in 88% of both the underground and surface mines consist of fireclay, shale, draw slate, or claystone. The results of the NGR testing indicate that the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1993

The original work statement of this contract was entitles: 'A Accident Analysis Model for Use in Underground Coal Mines.' The contract was scheduled for a duration of 26 months and was to be in three phases: Phase I - Model Development, Phase II - Application of the Model, and Phase III - Installation, Monitoring and Evaluation of the Model. Alter three months in Phase I, it became apparent that much of the needed data for the model was nut available and could not be made available within the original study schedule. Proceeding as plumed would have resulted in a model of limited utility. Personnel from Theodore Barry and Associates and the Bureau discussed the problem in detail and mutually decided to utilize the majority of remaining funds to assist the Bureau in solving these data problems and develop a stronger ongoing capability for safety analysis within the Bureau. Both tie contractor and the bureau officials involved believed that this decision greatly enhanced the Bureau's ability to develop future accident prediction models, whose rigor would greatly exceed what was currently possible.

Jan 1, 1972

By Robert A. Miller

This computer program determines the price per ton of coal needed to obtain a profit of 12 percent discounted cash flow. From a predetermined equipment and manning list, the program calculates all costs and prints seven tables, Including the equipment and manning tables and the discount cash flow table. Forty-four of the input variables may be readily changed to study their effects upon the final price per ton of coal or upon individual cost items. The method is adaptable for any type of mining and with additions, for beneficiation processes. This program was written in Fortran IV for use on the IBM 11302 and with few modifications can be used on other computers.

Jan 1, 1971

By Heinz W. Sternberg

The literature on electrochemical treatment of coal is reviewed, and possible avenues of further research in this field are discussed in this report. Electrolytic reduction of finely distributed coal resulted in the addition of as many as 9 atoms of hydrogen to 100 atoms of carbon. Reduction of coal extracts at controlled potentials indicated the presence of condensed aromatic hydrocarbons and reducible quinones in coal. As much as 65 percent of low-rank coal can be made alkali soluble by electrochemical treatment. Higher rank coals gave smaller yields of alkali-soluble products. However, the nature of this reaction is not clear. The difficulty of reducing coal electrolytically is probably due to the insolubility of coal and not to any structural peculiarity. Reduction of coal by electrolytically generated radical anions appears to be a promising approach for further research.

Jan 1, 1962

By Floyd R. Anderson

Noise control of existing pneumatic drills is difficult and runs into cost, performance and weight penalties. A need exists for a start-from-scratch approach for quiet pneumatic rock drills. The designs based on Leavell Principles which has been successfully used in demonstrating a quiet and vibration free paving breaker, is the concept chosen here. This report shows the feasibility of a quiet stoper for drilling roof bolt holes in coal mines. The work is directly applicable to pneumatic percussive rock drills. The report shows an oscillator based on patented Leavell concepts which results in a vibration free tool and noiseless exhaust. Dynamics of the oscilator is analyzed. Independant rotation of drill rod is provided by an air motor (screw expander) and flushing of cuttings is accomplished by an air ejector in a compact lower housing. The feasibility of no exhaust noise, low drill machine noise, and vibration free casing is discussed.

Jan 1, 1977

By Catherine C. Kilgore

The Bureau of Mines investigated the availability of fluorspar (CaF2) from 36 U.S. and 50 foreign mires and deposits in 13 countries. Only 6 U.S. properties are considered to be economic, as 29 domestic deposits were found to have an average total cost of production that was uneconomical at a breakeven (0-pct) discounted-cash-flow rate of return (DCFROR). The 50 foreign properties evaluated represent at least 55 pot of demonstrated fluorspar resources located in market economy countries and China. Al I evaluated foreign operations were found to be economic to marginally economic in January 1984 dollars when compared against published prices for each country. Reserves for 56 properties totaled 97 million metric tons (mt) (recoverable Ca F,) from demonstrated ore resources of 344 million mt that contained 123 million mt CaF2. The average total cost needed to cover all costs over the life of each operation was determined for all recoverable fluorspar products. Comparisons of ruining, beneficiation, and transportation costs per metric ton of fluorspar concentrate illustrate advantages between countries. Of the three countries with the greatest fluorspar production, China, with its high-grade, low-cost operations had the lowest weighted-average total cost of production ($38/mt concentrate), Mexico was next, at $54/mt concentrate, and benefited in U. S. dollar terms from the devaluation of the peso. The Republic of South Africa needed an average of $90/mt of concentrate to cover all costs of production at its large low-grade deposits.

Jan 1, 1985

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1987 was $446.6 million, an increase over that of 1986 and the first increase in 3 years. Alabama was second in the Nation in production of bauxite and ferroalloys; third in bentonite, crushed dolomite, crushed marble, and fire clay; and fourth in masonry cement. Trends and Developments.-Employment in the minerals industry remained relatively low for the second year even though the overall unemployment rate dropped to 7.9% by December. Employment in mining and primary metals dropped about 10% and 2%, respectively.

Jan 1, 1989

By W. J. Wiehagen

The Work Crew Performance Model (WCPM) seeks to define performance variability within similar tasks of an underground work crew and relate observed variability to a cost consequence. Performance variability is described using work site observations to determine the adherence to job elements con¬tained within a standard operating procedure. Key components of the WCPM include (1) job definition through task analyses and the ranking of job elements by perceived cost consequence, (2) observational techniques for establishing performance baselines by measuring adherence to safe and proficient job procedures, and (3) cost linkages between adherence to task procedures and measures of consequence for noncompliance. Data presented within this report were obtained through the study of shuttle car operation in an underground mine in Appalachia. Observed adherence to safe and proficient job procedures by opera¬tors matched well with the consensus profiles (measured through a nominal group technique) with min¬ing personnel. It was also found that experienced operators consistently outperformed less experienced, incidental operators. These findings imply potential use of the WCPM as a practical procedure for thinking systematically about the choices available to reduce performance variability. Field application of the model can offer useful data to evaluate training and financially support performance improvement strategies that can be tested for their ability to reduce human error.

Jan 1, 1994

By Henry P. Chandler

TONNAGE of natural abrasives sold or used in the United States in 1959 increased 12 percent. Artificial abrasives produced in the United States and Canada jumped 24 percent. Imports, exports, and reexports of abrasive materials also showed gains. Sales of grinding wheels were up 33 percent and coated abrasives 17 percent. FOREIGN TRADE Imports of abrasive materials totaled $91 million, an increase of nearly 51 percent over 1958. Chief commodities contributing to [ ]

Jan 1, 1960

By D. Bienstock

Using a nitrided fused-iron catalyst, the Bureau of Mines investigated the Fischer-Tropsch reaction in the oil-circulation process. The nitrided iron was quite stable and permitted the longest run obtained thus far in the oil-circulation process without the need for reactivating the catalyst--3,700 hours of operation. The effects of several operating variables--temperature, pressure, gas-recycle ratio, space velocity, synthesis-gas composition, and synthesis with and without reflux of oil to the reactor--on the production of oxygenates were studied. The importance of removing reflux oil and of high gas recycle in increasing the oxygenate content was shown. A finished gasoline containing 28 percent by weight alcohols was produced. The research octane number (RON) was 92.9 clear, increasing to 98.5 with the addition of one milliliter of tetraethyl lead (TEL). INTRODUCTION The Federal Bureau of Mines has been engaged since 1944 in a research and development program on the synthesis of gasoline from coal. Gasification of coal with steam and oxygen to yield a "synthesis gas"--a mixture of carbon monoxide and hydrogen--is being investigated at Morgantown, W. Va., and the synthesis of gasoline by catalytically reacting carbon monoxide and hydrogen over iron by the Fischer-Tropsch reaction is being investigated at Bruceton, Pa.

Jan 1, 1960

By J. Dean Warner

Alaska contains many critical and strategic minerals that are scarce in the conterminous United States. Among these are tin, tantalum, and columbium. This Bureau of Mines report summarizes available data on the production, reserves, and occurrences of these minerals in Alaska. Alaska produces about 200,000 lb of tin per year, with historical production since 1901 estimated to have totaled 5,830,600 lb. Measured, indicated, and inferred tin reserves total over 140,000,000 Ib. Much of the tin production has been from the placer mines of the western Seward Peninsula; however, most of the reserves are in that area's lode deposits. Alaskan tin occurrences are part of a belt of tin mineralization that extends along the western coast of North and South America. The Alaskan portion of this "tin belt" comprises placer occurrences and lode occurrences of five major types: greisen, vein, skarn, pegmatite, and volcanogenic massive sulfide. Greisen and vein occurrences are the most abundant, but skarn deposits have historically been the most economically important. Columbium and tantalum have not been produced in Alaska; however, they may be recoverable as byproducts of tin, tungsten, gold, or uranium mining. Approximately 135,000 Ib of columbium oxide (Cb205) are inferred within the Tofty placer deposits in the Manley Hot Springs district.

Jan 1, 1985

By F. W. Lee

List of GEOPHYSICAL ABSTRACTS

Jul 1, 1932

By T. T. Tomimatsu

This? Bureau of Mines paper discusses the corporate structure dynamics, methods of financing, and financial assessment approaches that should be utilized to evaluate the economic health of the coal industry. It suggests rates of return and other measures of corporate economies necessary to attract capital required to finance emerging coal demand, plus impact of coal sales to total revenues. The study illuminates the activities of 30 selected coal-producing companies, including their subsidiaries or affiliates, that were responsible for approximately 60 percent of the total U.S. production in 1974. The selected firms are not all primary coal producers; many of the larger producer's are classified by the financial institutions as petroleum, metal, and steel producers, public utilities, or chemical industries. The bituminous coal industry is highly competitive as to price, service, and quality of pronuct and is subject to competition from other noncoal energy sources. The top 15 bituminous coal-producing companies mined about 46.6 per-cent of the Nation's total production in 1974, and the balance of approximately 3,885 companies were responsible for the rest of the production. Thus, the U.S. bituminous coal industry is not an oligopoly. Today, about 65 percent of the Nation's total coal production is consumed by electric power utilities and 26 percent by steel, space heating, and other industries; the balance of 9 percent is exported.

Jan 1, 1976

By R. B. Anderson

SULFUR poisoning of iron catalysts in the Fischer-Tropsch synthesis was investigated at the Bureau of Mines, because synthesis gas produced from coal contains sulfur compounds. Tests of two typical iron catalysts with synthesis gas containing known concentrations of H2S were made to determine catalyst life as a function of sulfur concentration to ascertain the type of gas purification required. Fixed beds of activated steel turnings and a fused iron oxide catalyst were investigated in sulfur poisoning tests at 21.4 atmospheres with IH2+100 gas containing 6.9, 23, or 69 mg S as H2S per cubic meter (0.3, 1.0, and 3.0 gr per 100 cu. ft.). In tests of reduced catalysts at constant temperatures, more than 80 percent of the activity was lost when 0.5 mg S/g Fe was introduced. Poisoning of nitrided or carbided fused iron oxide catalysts to a given extent required more than twice as much sulfur than for the corresponding reduced catalyst. When the synthesis temperature was increased to compensate for loss in activity, tests of the fused iron oxide catalysts at constant productivity could be continued for 19 to 98 days. The tests were terminated by clogging of the reactor, presumably caused by carbon deposition. One objective of the present work was to determine if synthesis gas, purified by the Bureau of Mines' hot-potassium carbonate process for removing H2S, OOS, and CO2, is suitable for synthesis on iron catalysts. The sulfur content of the gas purified by tills process is in the range of concentrations used in the present work. In constant-productivity tests of nitrided fused iron oxide catalysts with synthesis gas containing 6.9 mg S/m3, catalyst lives are nearly long enough for serious consideration of tills mode of operation. However, factors relating to selectivity and stability of the catalyst indicate that this type of operation is impractical for a commercial process. On this basis additional gas purification, such as iron oxide boxes following a hot potassium carbonate scrubber, is desirable.

Jan 1, 1965

By Walter Kawa

Bureau of Mines research on the hydrogenation of coal has been concerned with developing processes that could be used to supplement the Nation's petroleum and natural gas resources. Motor fuel was produced in a subsidized coal hydrogenation industry in Europe prior to 1945, but the process used is still not economical and other methods of producing liquid and gaseous fuels from coal are being investigated. As an aid to the planning of coal hydrogenation research, a literature survey was made of processes or methods of hydrogenating coal that differ from the subsidized or conventional process. This report contains a bibliography of unconventional methods of hydrogenating coal and a brief discussion of the economics of the conventional method. A general discussion of unconventional methods is included, and the advantages and disadvantages are pointed out where possible. The survey supplements a previous Bureau of Mines survey3 and a comprehensive review published in 1930.4

Jan 1, 1964