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The principle activities of the Explosives Research Laboratory from July 1, 1961 to June 30, 1962, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1962; in general, the research reported in these publications antedates the report period. Part 3 gives the results of an investigation which, although too limited to warrant separate publication, merits presentation in some detail because of current interest in ammonium nitrate-fuel oil compositions.

Jan 1, 1964

By Manuel Gomez

This report presents low-temperature tar data from studies by the Bureau of Mines of tars produced in an externally heated (entrained state) pilot-plant-scale retort. Analytical data covering 20 low-temperature tars, derived from the. carbonization of various ranks of foreign and domestic coals, are tabulated. The character of the tar is discussed in relationship to carbonizing conditions and the rank of coal. It is seen that in carbonization techniques that employ entrainment or fluidization of the coal particle, carbonization conditions are secondary to coal rank with respect to tar-oil yields and composition. The influence of distillation conditions on recoverable yields of tar products is presented. The probable yield of commercially important chemical products, based on a ton of pure (moisture- and ash-free) coal, are predicted. INTRODUCTION Low-temperature tars produced by entrainment or fluidized carbonization techniques that employ internally heated reactors represent the most nearly primary tart produced by industrial processes. In brief, such a process involves the application of a heat gradient to the coal particle "boiling" or suspended in a turbulent state in the reactor chamber. Conditions are observed so that the coal particle remains suspended within the reaction zone by a gas stream for a time interval commensurate with maximum tar-oil yield. The heat necessary for the carbonization reaction may be obtained entirely from the hot (preheated) gas stream, or it may be derived partly from the combustion of the volatile products and char by the transport gases, usually air. The volatile material moves out of the carbonizing zone at a rate that approaches the velocity of the transport gas. Carbonizing conditions are ideal when a minimum particle residence time is obtained within the reactor at a given temperature and a maximum yield of condensable volatile matter is released. In industrial practice this objective is a compromise.

Jan 1, 1957

By J. F. Neill, O&apos

The manganiferous schists occurring in the vicinity of Kings Mountain, North and South Carolina, suggest significant tonnages of potential submarginal ores. Although some reconnaissance work in connection with these deposits has been reported, no recent information has been published. Evaluation of the schists as a possible domestic manganese resource has not always adequately considered the fact that the manganese content occurs quantitatively both as oxide and as the silicate, spessartite. The Bureau of Mines investigation herein reported includes preliminary studies to indicate the extent of manganese oxide mineralization and to deter-mine the amenability of the material to sulfur dioxide leaching. The field reconnaissance studies suggest a resource containing in one area an average of 6.4 percent manganese as oxide. The procurement of depth information was beyond the scope of the investigation.

Jan 1, 1962

Longwall minim; is a highly mechanized, high productivity mining method that is finding increasing applications in coal. Although the method would be highly advantageous in certain hard rock mining applications it cannot be applied in hard rock because no suitable cutterhead exists for such materials. The wedge longwall cutterhead is a, roller cutter device that is wedge-shaped, with cutters arranged to eliminate the very large normal force ordinarily required to cause such cutters to penetrate hard rock. However, the wedge geometry cannot be extended to a point: special nose cutters are needed to open a narrow slot for the wedge. This report describes the design, fabrication, and successful field testing of these critical nose cutters.

Jan 1, 1974

By Terry R. Neumann

In 1987 and 1988, the U.S. Bureau of Mines conducted a mineral resource investigation of the 31,400-acre Muddy Creek Wilderness Study Area (UT-060-007). The investigation was requested by the Bureau of Land Management and authorized by the Federal Land Policy and Management Act of 1976 (Public Law 94-579). The study area is located in Emery County, Utah, about 50 air-miles southwest of Green River, Utah. The wilderness study area is in the San Rafael Swell region of the Colorado Plateau Physiographic Province. Rocks in the area consist of gently dipping sedimentary strata of Permian, Triassic, and Jurassic age.

Jan 1, 1988

By Dipak C. Talapatra

This report describes the development of guidelines for design, inspection and maintenance of automatic couplers. In order to devise the guidelines, performance requirements for automatic couplers were carefully established. This was clone through a comprehensive survey of coupler manufacturers and extensive observation of automatic couplers in service in a broad spectrum of mines. The capability of the couplers to withstand the demands of the mining environment in terms of strength characteristics, gathering range, curve negotiability, and other factors were all carefully evaluated. An analysis of coupler related accidents for the years 1972-1976 was carried out to provide information on the safety and reliability of existing automatic couplers. This formed an important input to the development of the guidelines. It is expected that these guidelines will he useful to coupler manufacturers for establishing designs for improved automatic couplers, and to mine operators for maintaining their couplers in a safe and good operating condition throughout their expected lifetimes. This report is in two volumes: Volume l - Technical Report Volume 2 - Design, Inspection, and Maintenance Manual

Jan 1, 1977

By J. D. Noll

Elemental carbon (EC) is used as a surrogate for regulating the exposure to diesel particulate matter (DPM) of underground metal/non-metal miners. EC was chosen as a surrogate because EC is selective to DPM and is a major component of DPM. Using EC as a surrogate also gives one the advantages of no sampling artifacts and being able to sample at all locations in the mine. Currently, EC represents DPM well in underground mines. Some control technologies have been shown to possibly alter the relationship between DPM and EC and characteristics of DPM. Therefore, future work will investigate the relationship between DPM and EC as new control technologies are implemented.

Jan 1, 2002

[RESULTS OF THE PRIMARY CONVENTIONAL PERFORMANCE AND COST MODEL OF THE UNIT OPERATIONS OF UNDERGROUND PERCUSSIVE DRILLING AND BLASTING]

Jan 1, 1977

By D. E. Wolfson

As part of its overall program of coal-carbonization research, the Bureau of Mines is studying the coking properties of coals from various fields of this country. Few of the coals included in this survey are used for the manufacture of metallurgical coke, although some well-known coking coals necessarily are tested to provide comparative data, particularly on blending properties. The overall objectives of the study were given in detail in a previous report.3/ The inherent suitability of coal for metallurgical purposes, as distinguished from economic considerations, depends primarily on (1) the available reserves, (2) chemical composition, (3) preparation characteristics, and (4) carbonization behavior. These items are considered in selecting coal for carbonization tests.

Jan 1, 1956

By William W. Adams

A larger measure of safety attended the operation of the stone quarries and related plants in the United States during the calendar year 1935 than in any other year for which annual records are available for the industry. The accident rate, covering fatalities and nonfatal injuries that disabled an employee beyond the remainder of the day on which the accident occurred, was 38.19 per million man-hours of work performed. The nearest approach to this favorable record was in 1932 when the rate was 38.48. The rate for 1934 was 41.82; hence the record for 1935 was 9 percent better than that for 1934. Reports from operating companies showed that 51 men were killed by accidents in 1935 and 4,152 men were injured. (See table 37.) The industry employed 73,005 men and performed 110,033,341 man-hours of labor, an average of 1,507 hours of work per man. Measured in man-days, the total volume of labor was 14,623,303, or an average of 200 days of 7.52 hours per day for each man employed. These figures are not strictly comparable with similar figures for the preceding year, as the, coverage of the industry was more complete for 1935 than for 1934 because special facilities were available to the Bureau of Mines for conducting the 1935 canvass that were not available for the 1934 canvass. Reports covering identical plants that were active both in 1934 and 1935 indicate a reduction of about 7 percent in the number of men employed in 1935. This fact suggests that the apparent increase in the number of workers in 1935 is attributable chiefly, if not entirely, to the more complete coverage of operating plants in 1935. The plants from which this inference is drawn employed 21,799 men in 1934 compared with 20,248 in 1935.

Jan 1, 1937

By Russell J. Foster

In this Bureau of Mines report a selection process has identified 14 nonstockpiled materials (cesium, gallium, hafnium, indium, osmium, rhenium, rhodium, rubidium, ruthenium, scandium, selenium, tellurium, thallium, and zirconium) that are linked to the continuing evolution of high-technology fields such as electronics, catalysis, and energy, and that have limiting factors associated with domestic availability. A qualitative assessment of the "potential criticality" of these materials was made through a consideration of end uses, demand trends and forecasts, production, mineral reserves, byproduct status, alternative supply sources, substitution and conservation options, and recyclability.

Jan 1, 1988

By A. J. Barry

Recent developments in mechanizing longwall it mining in Europe have aroused considerable interest among American coal-mine operators because this method provides an opportunity to improve safety, production, efficiency, and recovery. The success of longwall mining in Europe has depended to a large degree on development of effective roof-control systems. One of the major contributing factors in designing these systems is development off improved supports, which combine high load-bearing capacities with controlled yield characteristics, to use in the face areas. Other factors that relate to successful longwall mining involve knowledge of the structural properties of the strata above end below the coal bed being mined, movements of these strata induced by mining, and effects of the strata movements on the strata itself, as well as on the support system used. Extensive studies of the above factors relating to long-wall mining have been made in coal-mining countries abroad, and corresponding studies (1, 2, 3, 4, 5)3/ of room-and-pillar operations have been made in this country. Although descriptions and results of experiments of mechanized longwall operations in the United States have been published (6, 7, 8), this is the first instrumented study of roof behavior on a longwall operation. In view of the possible widespread application of this method of mining to American coal mines, where underground mining conditions are different from those found in European mines, an investigation was conducted at a mechanized longwall operation inn the Lancashire No. 15 mine, Barnes & Tucker Co., Cambric County, Bakerton, Pa., to study the factors that affect roof control. This report describes this investigation and discusses the results. ACKNOWLEDGMENTS This investigation was made under a cooperative agreement between the Bureau of Mines and the Barnes & Tucker Co., Barnesboro, Pa., end was conducted in the Lancashire No. 15 mine located at Bakerton, Cambria County, Pa. The authors acknowledge the cooperation given by Richard Z. Todhunter, Sr., president, Richard T. Todhunter, Jr., general manager, and other mine officials and employees of the Barnes & Tucker Co. Mr. Edward Thomas, chief, Roof Control Section, Bureau of Mines, Washington, D. C., and Dr. Leonard Obert, chief, Applied Physics Branch. College Park, Md., collaborated in the planning and promulgation of the program investigation.

Jan 1, 1954

By R. S. Dean

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

Jan 1, 1941

By R. S. Dean

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

Jan 1, 1941

By John J. Sammarco

This report details the testing and evaluation of a modular azimuth and positioning system (MAPS) to provide navigational information for a continuous mining machine. Vehicle navigation is part of the U.S. Bureau of Mines research program in computer-assisted mining serving as a tool to increase mining health, safety, and productivity. The Bureau is investigating other navigation systems, but MAPS seems to have the most promise. MAPS was installed on a continuous mining machine. An operator used the machine to cut coal while researchers collected machine and MAPS data. A comparison of MAPS data for xy position and data obtained with an electronic transit showed an increasing error for MAPS. After 30 min of operation, the easting position error was -0.02 m, and the northing position error was 0.019 m; after 60 min of operation, the easting position error was -0.19 m, and the northing position error was -0.26 m. Modifications to MAPS software and to the operational procedure of the machine significantly reduced this error by a factor of 3.7. Researchers continue to reduce these errors.

Jan 1, 1993

By Bruce Pinkston

This report presents a description of the Prototype Demonstration Vehicle developed under U.S. Bureau of Mines Contract No. JO 366003, "Improving Man Transit Safety". This vehicle was constructed to assess the feasibility of a set of equipment related guidelines which were drafted in Phase I of the same contract. State-of-the-Art improvements were embodied in such areas as collision survivability, occupant comfort, and multiple mode (on and off rail) operation. The electric battery-powered vehicle carries a twelve man section crew at speeds up to 12 mph. The description of the demonstration vehicle is presented in Volume I. Safety Guidelines are presented in Volume II.

Jan 1, 1981

The Federal Coal Mine Health and Safety Act of 1969 limits to 2 milligrams per cubic meter (for dust containing a maximum of 5% quartz) the average respirable dust concentration to which individual miners may be exposed. Section 205 of the Act directs that an appropriate exposure formula for dusts with quartz content in excess of 5% be established. This formula, entered in F. R. Document 70-12351 filed September 16, 1970, is 10 milligrams per cubic meter divided by % quartz. Thus, the total respirable dust exposure permitted limits the quartz to a maximum of 100 micrograms. For example, if % quartz is 5%, 10 mg/5 = 2 milligrams, and (.05) (2 mg) = 100 micrograms. Similarly, if % quartz is 10%, 10/10 = 1, and (.10) (1 mg) = 100 micrograms, etc. If the % quartz is less than 5%, the 2 mg/M3 limit prevails.

Jan 1, 1974

By Kim B. Shedd

The U.S. Bureau of Mines Particulate Mineralogy Unit examined the habits of six zeolite minerals commonly occurring in domestic zeolite deposits. Mineral habit is of interest because current theory on the potential for sarcoma production in test animals emphasizes the size and shape of mineral particles, without regard to composition or structure. A scanning electron microscopic study revealed that, of these six minerals, only mordenite and erionite crystallized in acicular to fibrous habits, The fibrous varieties of these two minerals were characterized by size and shape on the transmission electron microscope, and their dimensions were compared with those of asbestos and amphibole cleavage fragments. When comminuted, these two minerals possess "fibrosity indices" similar to those of amphibole cleavage fragments. One sample, a rare woolly erionite, has uniform widths, large aspect ratios, and a "fibrosity index" similar to those of asbestos.

Jan 1, 1982

By Robert H. Ridgway

This circular outlines salient facts regarding the sulphur industry of the United States and the world. It is founded chiefly upon published information available in the literature of the subject. The Bureau of Mines has in its files additional, more detailed data upon many of the topics presented very briefly here, and will endeavor to assist the mineral industries and the public by giving further information in response to individual inquiries. It will welcome comments, criticisms, and contributions of data that may assist in making later editions of this circular more accurate, or in developing more fully the bureau's mineral files pertaining to sulphur. Throughout this paper sulphur is used to designate crude sulphur or brimstone, not sulphur produced from pyrites or' smelter gases.

Jan 1, 1930

By James C. Fowler

As report covers the installation and testing of a permanent seismic monitor system at the Loveridge Mine in West Virginia. The testing of the system showed several things: 1. Getting the seismic data hack to the central computer in a usable form is possible 2. It is possible to detect small explosions. 3. The use of this system as a auxiliary system to detect hammer blows from miners trapped in the area of one of the geophones is possible.

Jan 1, 1974