Search Documents

By N. Kumar Kittusamy

By Henry P. Chandler

COMBINED sales of abrasive materials in the United States during 1956 increased at about the same rate as the value of the Gross National Product in terms of 1954 dollars,3 which was nearly 3 percent. However, some segments of the industry did not follow the general pattern. Sales of abrasive grinding wheels increased 9 percent in value. Sales of surface-coated abrasives declined 5 percent in quantity hut increased 1 percent in value, Production of crude silicon carbide in the United States and Canada advanced both in tonnage and value, but that of abrasive-grade [ ]

Jan 1, 1958

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 R. L. Hopkins

Some typical thiacyclopentanes and thiacyclohexanes were synthesized to provide reference compounds needed for the identification of sulfur compounds in crude oils. Two general methods of synthesis were employed: (1) cleavage of 2-alkyltetrahydropyrans with hydrogen bromide followed by the reaction of the resulting dibromoalkanes with sodium sulfide and (2) the catlyzed reaction of cyclic ethers or 1)4-or 1)5-alkanediols with hydrogen sulfide. Both methods produced mixtures of 2-alkylthiacyclopentanes and 2-alkylthiacyclohexanes with 2-alkyltetrahydropyran as the starting material. The structures of the reaction products were established by analysis for sulfur; desulfurization; gas-liquid chromatography (GLC); mass, infrared, and nuclear magnetic resonance (NMR) spectra; and an alternate synthesis. The synthesis of the cyclic sulfides contributed substantially to the identification of 10 members of this class of sulfur compounds in crude oil.

Jan 1, 1967

By E. L. Garton

[The oil-producing district, "Southern Oklahoma," is generally considered to be that part of the: State lying; southwest of the Arbuckle Mountains. It includes six counties: Carter, Cotton, Garvin, Jefferson, Kiowa, and Stephens. At present cost of the oil is produced from formations of Pennsylvania age. The individual crude oils resemble those produced in other parts of the State, except that the sulfur content is rather high. This report is a continuation of a study of Oklahoma crude oils3/ being made, by the Bureau of Mines, Petroleum Experiment Station, Bartlesville, Okla. in cooperation with the State of Oklahoma. Analyses are given of 27 samples obtained from 21 fields in the southern part of the State, end the physical and chemical characteristics of these crude oils are discussed briefly. Analyses of crude oils from other Oklahoma areas and publications in which these analyses may be found are listed in tables 2 and 3.]

Jan 1, 1941

By E. H. Denny

The subject of haulage and heisting hazards is one that merits the attention of everyone engaged in mining. The purpose of this circular is to the importance of such hazards as are shown by Bureau of Mines accident figures, to give some examples of recent accidents and briefly analyze the immediate contributing causes, and to discuss some general means found by metal- and coal-mining companies to minimize those hazards. Haulage and hoisting accidents collectively constitute the second most common cause of accidents in and about coal mines and the third most common cause in and about metal mines. In both these types of mines falls of ground cause more accidents than haulage, and in metal mines falls of persons in raises and similar openings also exceed haulage accidents in number.

Jan 1, 1942

By Robert L. Lagace, Michael A. Grossman, Alfred G. Emslie

This supplement to the final report is a collection of interim and monthly reports and working memoranda prepared during the course of this program to document the progress, methods and results of the work. The supplement is divided into the self-contained sections briefly described below. I. SELECTED MONTHLY TECHNICAL LETTER REPORTS - This section is a collection of selected monthly technical letter reports that briefly summarizes the chronological development of the analyses and results, including the different concepts, theoretical approaches, and methods of data reduction and analysis explored, and the discoveries, insights and findings made along the way. More detailed treatments of the key developments and results are presented in the interim reports and working memoranda reproduced in subsequent sections of this supplementary report, and in the separately published final report. II. BACKGROUND THEORY FOR MEASUREMENT PROGRAM ON MEDIUM AND HIGH FREQUENCY RADIO TRANSMISSION IN COAL SEAMS - Working Memorandum - This working memorandum gives the initial background theory needed to guide the planned measurements and data analyses of this program to describe the propagation of radio waves-in coal seams for the frequency range of 50 to 5000 kHz. III. MODELLING AND DATA ANALYSIS OF IN-MINE ELECTROMAGNETIC WAVE PROPAGATION - Interim Report - This interim report presents detailed treatments of the data analysis and modelling techniques used, and the associated results obtained from conductor-free area propagation data measured by T. Cory in the first set of six coal mines. The mines were located in three highcoal seams; the Pittsburgh seam in northern West Virginia, the Pocahontas No. 3 seam in Virginia, and the Herrin No. 6 seam in Illinois. IV. ANALYSIS OF MF PROPAGATION DATA FROM MARGARET NO. 11, NANTY GLO, EHRENFELD, AND ADRIAN COAL MINES - Interim Report - This interim report presents detailed treatments of several improved data analysis and Modelling methods applied to, and results obtained from, conductor-free area propagation data measured by T. Cory in the second set of four coal mines. These mines were located in three low-coal seams; the Upper Freeport seam in Pennsylvania and West Virginia and the Lower Freeport and Lower Kittaning seams in Pennsylvania. In addition, this report contains a reprint of two papers presented at a Bureau of Mines sponsored EM Guided Waves in Mine Environments Workshop held in Boulder Colorado. One paper describes the three-layer theoretical model and its application to the conductor-free data from the first six mines, while the second paper describes the theory developed for the coupling of loop antennas to a cable in a mine tunnel in a coal seam, and the model's application to data in the vicinity of cables taken at the Margaret No. 11 mine. V. A METHOD FOR NONINTRUSIVE, IN-SITU MEASUREMENT OF COAL AND ROCK CONDUCTIVITIES IN A COAL MINE TUNNEL - Working Memorandum - This working memorandum briefly describes a possible direct method, and its potential advantages and shortcomings, for performing in-situ measurements of coal and rock conductivities. VI. MODELLING AND DATA ANALYSIS OF IN-MINE ELECTROMAGNETIC WAVE PROPAGATION FROM 50 to 5000 kHz - Interim Report - This interim report presents a summary comparison of theoretical and experimental results for conductor- free areas in eleven coal mines located in seven coal seams. It also summarizes the findings and their implications for intrinsically-safe, portable radio communications between roving miners.

Jan 2, 1980

By D. Harrington

Although it is impossible to give definite final figures at this time on Nation-wide accident occurrence in 1933 , enough data are at hand to indicate that the progress in safety in the mining industry, which first became apparent in 1930 and was accentuated in 1931 and 1932 , was continued and much improved in 1933. This improvement was of considerable magnitude in mining both bituminous coal and anthracite but was not so great in other branches of the mining industry . While the volume of work done in all phases of mining increased in 1933 over that in 1932 , the exact amount of the increase is not yet known . Usually increased activity in mining is accompanied by even greater increase in the rate of occurrence of accidents to the workers , but happily it appears that this " rule " was not operating in 1933 --at least in the coal -mining industry .

Oct 1, 1934

Overexposure to noise is a widespread, serious health hazard in the mining industry, and causes hearing losses to a large percentage of the mining population. Recognizing this fact, the Bureau has a major on-going research effort to address this problem area. These proceedings include an overview of the Bureau noise control program and summarize nine selected noise control research programs.

Jan 1, 1984

By R. R. Sayers

"An important, function of the U.S. Bureau of Mines is to instruct miners in first aid, and as a means of promoting interest in it first-aid contests are held under the auspices of the Bureau, usually in coop; ration with other interested organizations, especially the American Red Cross, the National Safety Council and various operators' and Miners' associations. It was early found that the method of judging first-aid meets is one of the most vital factors in determining the degree of success of the meet.It may be safely stated that there is no method for the judging of first-aid contests that has proved ideal. A method that would give the most uniform judging would necessitate the rating of each team by the same judge or committee of judges and, in order that a judge may rate a team satisfactorily, he should see that team perform several events and average the ratings. Such a procedure is not practicable where there are many terms entered in the contest, as it would prolong the meet indefinitely. To overcome this objection the method has been tried of assigning separate judges to each team but this brings in a new factor the individuality of the various judges, some of whom rate closely, others loosely. The next development was to average the judging by having the judges rate different teams for each event. This would seem to solve the problem out it has been found, after using the method over a wide area for a considerable period of time, that the differences in the judging are too marked to be at all satisfactory. The next development was to appoint a committee of chief judges three to five in number especially trained and experienced, to aid the individual judges in rating the teams. This method has proved satisfactory at small meets but, as committee must review the work of each judge on each event, it has not been deemed feasible for a large meet."

Nov 1, 1920

The purpose of this study is to develop designs to facilitate and accelerate auger rotation stoppage (and auger rotation start up so as to promote auger disengagement during auger miner repositioning) and to provide a time delay and warning signal prior to auger start up to permit any miner s near the augers to get away from the augers before they start rotating. In the underground coal mines in the U.S., there are four auger miners that are currently in use. They are the Jeffrey 100L (see Figure 1-1) and 100M (see Figure 1-2), and the Wilcox WCM and the MK20A (see Figure 1-3).

Jan 1, 1974

By R. H. Schutz

This publication lists the respiratory protective devices approved by the Bureau of Mines as of December 31, 1968, and the names and addresses of their manufacturers. The purpose of this publication is to inform the public about approved equipment for safe use in mines and mineral and allied industries.

Jan 1, 1969

By Frank K. McIntosh

Bauxite was first discovered in Tennessee, at Chattanooga, in 1906, during the construction of' the McCallie Street tunnel through Missionary Ridge. Several years later, bauxite was found in sinking a well on the Perry or Isabella Stewart property. These and other deposits furnished a substantial tonnage for the abrasive and chemical industries during the years 1906 to, 1920. The search for domestic sources of war material prompted by World War II brought the Tennessee bauxite deposits to the attention of the Bureau of Mines. During the summer of 1942, James S. Cullison and E. Godwin, geologists of the United states Geological Survey, made a survey of the bauxite deposits of the area. In August 1942, Harold B. Ewoldt, a Bureau of Mines engineer, accompanied by the Geological Survey party visited the area and a drilling program was prepared. Drilling was started in November 1942 and continued until March 1943. A total of 2,519.5 feet in 38 holes was drilled on three properties.

Jan 1, 1949

By Clyde E. Williams

[As a results of work conducted during the past three years, the Northwest Experiment Station of the Bureau of Mines, in cooperation with the University of Washington at Seattle, Washington, has developed a process for the production of sponge iron. Commercial operation of this process in a 3 to 4-ton scale has been so satisfactory that its use on a large scale (20 to 100 tons per day) can be safely considered. Description of Process. The process consists in passing a mixture of iron ore and coal through a rotating kiln heated at one end to a temperature sufficient to convert iron oxide to metallic iron, discharging, cooling, and separating the sponge iron from the residual coke and silicious material on a magnetic separator. Both the coal and the ore should be crushed to peso as 6-meth scream, tans producing particles finer then 1/12 of an inch. Seventy-five parts of coal or other carbonaceous material arc charged with every 100 parts of ore), This large amount of coal is required in order to supply sufficient carbon to maintain a strongly reducing atmosphere in the charge, but may be reduced to about 65 parts per 100 parts of ore by recovering and using tae carbon that remains in the discharge product. Large-scale operation and refinements in furnace design should lower this ratio to perhaps 56 or 60 parts of coal to 100 parts of ore.]

Jan 1, 1924

By Richard L. Fowler

Study and development of sensing techniques and sensors were performed to aid shuttle car drivers in detecting obstacles and in guiding the car along the face haulage route. Microwave, acoustic, and optical sensing techniques were considered as part of the feasibility study for obstacle detection. Various guidance techniques, including wire-following and rib-ranging were investigated. Active optical sensing was selected for obstacle detection to obtain the beam coverage and sharp angular cutoff characteristics required within the packaging limitations defined by the shuttle car configuration. Rib-ranging guidance was selected to achieve a completely self-contained shuttle car system which responds to the existing mine geometry without need for wires, stripes, or other path defining devices. Extensive hybrid computer simulation runs were performed to evaluate various guidance techniques during the feasibility study. Subsequent simulation runs were performed to establish parameter values for the rib-ranging guidance system. The obstacle detection and guidance system was designed, fabricated and installed on a standard shuttle car. The system satisfied all applicable permissibility requirements of Schedule 2G. An experimental permit was issued to Bendix for operation in an underground coal mine. System evaluation tests were performed first above ground at the Bendix Research Laboratories. The simulation model was validated by these runs. Final testing was performed underground in an operating mine with an experienced shuttle car driver. All sensors successfully demonstrated the predicted performance capability during underground face haulage tests. Dust did not impair system performance and lens cleaning was not required during working shifts. Further development is required to achieve the desired obstacle detection performance. Closed loop steering control with manual override is recommended for the lateral guidance system. The guidance system should be an invaluable aid to low-coal shuttle car drivers where continuous mining machines are utilized.

Jan 1, 1973

By D. L. Bickel

This report presents a Bureau of Mines study intended to determine if horizontal stress trends exist and if the stresses can be projected for improved mine design in a selected coalfield. The horizontal stresses were determined in three mines in the Yampa Coalfield and one mine in the adjacent Danforth Hills Coalfield of northwestern Colorado. Stresses were determined from stress-relief measurements using a three-component borehole deformation gauge and overcoring techniques developed by the Bureau. A least-squares method of calculating the average rock stress components in the horizontal plane was performed. Physical properties of the rock from the test sites are also included. For the Yampa Coalfield, the maximum horizontal compressive stress in the floor ranged from 363 to 1,956 psi, and the maximum horizontal compressive stress in the roof ranged from 235 to 875 psi. For the Dan-forth Hills Coalfield, the maximum horizontal compressive stress in the floor ranged from 360 to 1,494 psi, and the maximum horizontal compres-sive stress in the roof was 1,033 psi. Results indicated a trend of low horizontal stresses in the Yampa Coalfield that have not impacted ground control conditions in mines less than 1,000 ft deep.

Jan 1, 1988

By H. Herbert Hughes

Soapstone commonly is associated with talc , and reports on either commodity usually contain a discussion of the other . From a geological or mineralogical standpoint the combination is justifiable , for soapstone essentially is impure talc . Commercially , however , the relation between them is remote . About 95 per cent of all talc sold in the United States is in ground form, whereas practically all soapstone is sold as furnace blocks or as fabricated structural slabs for many and diverse applications .

Feb 1, 1932

By Nan C. Jensen

Modern high-temperature metallurgical processes have created a demand for raw material for furnace parts and lining that not only will with-stand high temperatures is but will not react with the substance being melted in the furnace. Spark-plug insulators, laboratory ware, tanks for the glassmaking making industry, and saggers and kiln furniture for the chinaware and pottery trades also must be made of materials hat have high melting points. Among the minerals that can be employed for such refractory uses ore those commonly known as the "sillimanite group' -kyanite, andaluste, sillimanite, and dumortierite - and the allied minerals topaz and pinite. Consideration of the occurrence, properties, qualities, uses, and sources of supply of these commodities and the markets for them constitute the subject of this paper. General Features of Kyanite and Related Minerals Kyanite, andalusite, and sillimanite ire composed of three elements - aluminum, silicon, and oxygen ? and are called aluminum silicates. The have

Jan 1, 1943

In 2006, a total of 7,178 sand and gravel mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 ? Sand and gravel mines were the largest mining sector, comprising 48.2% of all mining operations. ? Sand and gravel mines were found throughout all 50 states and Puerto Rico.

Sep 1, 2008

By Office of Public Information

"The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau of Mines to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable.·This issue of the Bureau of Mines. List of Publications and Articles describes reports and articles published during the period January 1, 1985, to December 31, 1989. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960;1 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960;2 the 5-year lists of publications and articles from January 1, 1960, to December 31, 1964,3 from January 1, 1965, to December 31, 1969,4 from January 1, 1970, to December 31, 1974,5 from January 1, 1975, to December 31, 1979;6 and from January 1, 1980, to December 31, 1984.7"

Jan 1, 1990