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By R. V. Rahfuse

Noncaking 0- by 2 -inch subbituminous coal from New Mexico was gasified with air and steam at 205 prig using a stirred-bed producer to determine coal losses by entrainment in the gas for this low-sulfur, high-ash coal which contained 20 percent particles smaller than 1/16-inch sieve size. The use of fine-sized coal has particular importance because most production from mechanized mines is smaller than 2-inch size. This initial attempt showed technical feasibility for gasifying New Mexico subbituminous coal containing small-sized particles in fixed-bed producers without excessive coal loss by entrainment. Dust loss averaged about 2 percent of moisture-free coal, most of which was recovered from the gas. Ash clinkering was controlled by adding 1,010 lb/hr steam to reduce tempera¬tures in the combustion zone. Yield of low-Btu fuel gas, 150 Btu per scf, dry, amounted to 69,800 scfh from 1,490 lb/hr coal (as received) and 3,450 lb/hr air (dry).

Jan 1, 1974

By R. W. Fatzinger

The accident-frequency rate for placer mining in 1942 is reported as 36.923 accidents per million man-hours worked. This figure places placer-mining accident frequency slightly higher than that given for quarrying-35.7-but considerably under the 78.0 for coal mining and 56.5 for metal mining.4 Placer mining is subdivided into four types of activity: Underground, surface, dredging, and hydraulicking. It is the purpose of this paper to present and discuss safety practices in dredging and hydraulic mining; therefore, the following considerations will be limited to these two types of placer mining.

Jan 1, 1948

The Department of Interior, U.S. Bureau of Mines performs the task of estimating the quantity of coal reserves existing in each state on a county by county basis. As a part of Information Circular 8655, the Bureau of Mines established the criteria for the uniform estimations of coal reserves and listed the most recent estimates of coal reserves by county and by seam. At the same time however, the Bureau recognized that these figures represented the upper bound with regard to the estimated actually usable or obtainable reserves. Recovery of these reserves are subject to the mining methods used and to the resolution of such problems as the use of poor quality coal and competition provided by conflicting land use. These problems, in practice restrict the recovery of the estimated quantities of coal reserves listed in IC 8655. Another impact, the subject of this manual, is the impact resulting from previous mining activities. In particular, many of the reserve seams included in the reserve estimates overlie or underlie mined-out coal beds. Portions of these reserve seams may therefore be unmineable or at best may have a reduced quantity of extractable coal. In order to improve the accuracy of the coal reserve base estimates, the Bureau of Mines funded an effort1 to develop a systematic methodology for estimating the coal loss associated with the impact of previous mining activity. The coal loss calculation model (CLCM) described in this manual is a result of that effort and addresses the percentage of coal loss in reserve seams due to previous overmining or undermining.

Jan 1, 1976

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 John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By Elaine T. Cullen

Human beings are natural storytellers and story listeners. We learn very early that stories entertain us, but also give us the ?rules? about what is expected of us and how to make meaning of our experiences. Stories are integral to our lives, and have great power to change or influence how we think or how we react. They are an innate part of how we learn, and have obvious benefits to trainers or educators who are trying to impact what and how we learn. This paper and presentation discuss the social and cultural power of stories, and how they have been used to develop training for skilled blue-collar workers. Included will be examples as well as suggestions for trainers on where to find stories, what type of stories to pay attention to, and how to use them to improve occupational safety training.

Jan 1, 2008

By Mayo D. Hersey

This problem was taken up by the Bureau of Mines as a result of the oxygen explosion at the Jefferson Physical Laboratory of Harvard University , and other similar explosions , in order to supply technical information which would serve as a basis for safety precautions in the future . At the Harvard inquiry the fact was emphasized by the Massachusetts State Chemist , Mr. Walter M. Wedger , that we do not know the limiting pressures and temperatures above which compressed oxygen and lubricating oil are capable of spontaneous explosion . The problem is also of importance to the Army and Navy and to the Bureau of Mines in connection with the hazards incurred in the use of compressed and liquified gases in the repurification of helium. In fact , the risk of fires and explosions due to traces of lubricating oil coming into contact with high pressure oxygen is of serious interest to all concerned with the manufacture and use of oxygen , a commodity which is now being produced and distributed on a rapidly increasing scale . Part of the money expended on this investigation was from Army and Navy funds . The problem was undertaken by the Bureau of Mines at the suggestion of Dr. Charles E. Munroe , Chairman of the Committee on Explosives Investigations of the National Research Council , and referred to the Pittsburgh experiment station of the bureau.

Jul 1, 1923

By Douglas Milne

Most empirical and numerical approaches to design in rock mechanics incorporate rock mass classification. Numerical design methods generally use classification values to calculate input parameters for stress-based failure criteria. Empirical methods use classification to allow comparisons between similar rock mass conditions, generally based on a graphical design technique that differentiates stable and failed opening geometries. Classification systems are the best tool available for assessing rock mass properties; however, there are problems with classification systems that should be high-lighted. Rock mass performance can only be realistically estimated by coupling a unique description of the rock mass with known loading conditions. Current classification systems cannot provide a unique classification value. The weightings applied to quantify rock mass properties for classification can result in significantly different rock masses having the same classification values. These weightings have been proven effective for tunnel design and support, but classification systems are now used for many more applications. Rock classification systems evolved from a quick and easy field tool for estimating tunnel stability and support requirements. The need for a rapid field tool means that rock mass classification is relatively insensitive to improved methods of measuring rock mass properties. Problems with classification systems and their application are highlighted in this paper. These problems must be recognized and documented before improvements can be made. An understanding of the evolution of classification systems and their application for both numerical and empirical design approaches is invaluable in highlighting current shortcomings.

Jan 5, 2007

By D. A. Reynolds

THIS PAPER gives results of an investigation of the composition and carbonizing properties of coals from the Beckley bed, Caretta No. 5 mine, Susanna, McDowell County, and Glen Rogers No. 2 mine, Glen Rogers, Wyoming County, W. Va. The investigation included BM-AGA carbonization tests at. 800° and 900° C. and various chemical and physical tests designed to evaluate agglutinating, plastic, and expanding properties of coal. Both coals were of low-volatile bituminous rank, and each was blended with 70 and 80 percent high-volatile A coal from the Pittsburgh bed, Warden mine, Allegheny County, Pa. The Beckley bed was 39 to 58 inches thick at three points in the Caretta No. 5 mine, and the coal was 39 to 49 inches thick. The carbonizing sample contained 83.0 percent fixed carbon on the dry, mineral-matter-free basis. It contained 3.1 percent moisture, 15.8 percent volatile matter, 72.4 percent fixed carbon, 0.7 percent sulfur, and 8.7 percent ash, as carbonized. The ash softened at 2,680° F. The free-swelling index was 7;i, and the agglutinating value was 7.7. This sample fused weakly in the Gieseler plastometer; its blends with 70 and 80 percent Pittsburgh coal attained maximum fluidities of 830 and 600 dial divisions per minute, respectively. The single coal yielded 83.0 percent coke at 900° C. Yields of other carbonization products per ton of coal at 900° C. were: Gas, 9,950 cubic feet; tar, 3.5 gallons; light oil, 1.36 gallons; and ammonium sulfate, 16.3 pounds. Blending with Pittsburgh coal lowered the yield of coke and raised the yields of other products significantly. Caretta coal yielded strong, blocky coke at 900° C., 89 percent of which was plus-2-inch size. Strength indexes of 900° C. coke from 30:70 blends of Caretta No. 5 and Pittsburgh and of Pocahontas No. 3 and Pittsburgh coals were, respectively: 2-inch shatter, 68 and 53; 1%-inch shatter, 90 and 85; 1-inch tumbler, 50 and 53; and %-inch tumbler, 62 and 65. The specific gravity of the 900° C. gas from Caretta No. 5 coal was 0.272, and the heating values were 491 B. t. u. per cubic foot and 2,440 B. t. u. per pound of coal. The blends yielded much richer gas. Yields of tar acids and bases (0.09 and 0.04 gallon per ton, respectively) were within the normal ranges for low-volatile coals. Caretta No. 5 coal expanded 7.5 percent in the sole-heated oven at a charge density of 55.5 pounds per cubic foot. The blends containing 70 and 80 percent Pittsburgh coal contracted 4.8 and 7.5 percent, respectively.

Jan 1, 1953

By Alan G. Mayton

A prototype end-cab shuttle car (SC) design has been developed to improve protection and address ergonomic concerns of the SC operator in low coal mines. The new design features an end cab transversely mounted to the SC and equipped with a closed-circuit video system. The end cab was retrofitted to a low-coal SC and evaluated in surface trials at the U.S. Bureau of Mines. During surface trials, test operators evaluated the end-cab SC relative to visibility; cab features-space, seating, controls, and operator position; tramming-inby, outby, and turning corners; and dumping. Trials were conducted using 12 test subjects; 6 were experienced SC operators. Results of the trials were promising. Of the experienced operators, the only operator with low-coal experience gave the new design the highest rating. Four experienced operators rated the end-cab design "better" to "much better" than a standard center-driven, side-cab SC for visibility when tramming, protection from roof and rib hazards, and no change in seat position with direction of travel. This report discusses research to modify a used 21SC JOY SC, retrofit the SC with the Bureau-developed end-cab, and evaluate the retrofitted end-cab SC in surface trials.

Jan 1, 2010

By August J. Kwitowski

This report presents the results of a joint Bureau of Mines-U.S. Department of Energy project that evaluated a newly developed low-coal mining system: the 4M miniminer system. The evaluation took place from April through October 1981 and determined potential health, safety, and productivity factors for the mining system using the surface test facilities at Bruceton, PA. The planning, testing, results of testing, and a summary evaluation of the 4M miniminer system are included in the report. The miniminer system was found to be a very good concept with future potential for safe, healthful, and economic production in thin-seam mining. The mining system was also judged to have considerable potential for use in some coal seams that are presently considered unminable by other existing mining equipment. The preproduction, prototype version of the miniminer system that was tested suffered from several safety and production problems. These problems are also described, along with suggested remedies.

Jan 1, 1989

Research 82 highlights significant studies conducted during the past fiscal year at Bureau facilities and offices. Readers who want more information about the projects and studies summarized here can contact the researchers whose names and locations appear with each summary. General information on Bureau of Mines programs is available from the Office of Technical Information, 2401 E Street, NW., Washington, D.C. 20241. A listing of principal officials, a location map of field facilities, and a selected bibliography of publications and patents issued on Bureau developments during the past 3 years are provided.

Jan 1, 1982

By Richard L. Rains

The U.S. Bureau of Mines conducted a field study of mines and prospects of the Black Canyon RARE II area (No. 5061), Inyo County, California, from June to October 1981. Geological) geochemical, and geophysical studies were conducted by the U.S. Geological Survey. The Black Canyon RARE II area is east of Owens Valley and 6 mi east of Bishop, California. The principal mineral commodities are gold, silver, lead, zinc, and tungsten. Properties with resources in and adjacent to the area are listed in table 1; the locations are shown on figure 1.

Jan 1, 1983

By E. J. Gleim

[THE ORGANIC act under which Federal Bureau of Mines was established provided for the investigation of the safe use of electricity in mines. Each Congress appropriates funds for conducting this investigation. As part of this investigation, electrical apparatus used in mines is studied to determine if its operation and use might introduce a hazard. From this study, certain safety standards have been developed. These standards, established with the aid of both the manufacturer and user of such apparatus, are published in schedules, and apparatus that complies with the requirements set forth these schedules is classified as "permissible." This term is defined to designate apparatus as "completely assembled and conforming in every respect with the design formally approved by the Bureau of Mines." In the judgment of the Bureau, the manufacturers of such apparatus have adhered to certain minimum standards of safety in supplying a product that when properly used and maintained is safe for operation in mines where flammable gas or coal dust may accumulate. This work of the Bureau of Mines for increasing safety does not make it obligatory for manufacturers of mine equipment to produce only that of permissible classification. Before the effective date of the Federal Mine Safety Code,5 the Bureau sought to promote safety by recommending that mine operators install permissible equipment in gassy mines as a preventive measure against gas and dust explosions initiated by electrical equipment. For some years, the mining laws of several States have prescribed the conditions under which permissible equipment must be used. The Federal Mine Safety Code requires that ?all new electric face equipment and replacements of equipment purchased for mines where nonpermissible equipment is now being used shall be of a permissible type approved by the United States Bureau of Mines,]

Jan 1, 1955

By Raymond O. Dannenberg

The gas-combustion retort developed by the Federal Bureau of Mines at the Rifle Oil Shale Project near Rifle, Colo., is a continuous, gravity-feed retort. The heat required to convert the kerogen in the oil shale to liquid oil is generated by the combustion of product gas and carbonaceous residue remaining on the retorted shale after the kerogen has been converted to oil, gas, and residue. A study of the effects of the process variables on retort operation, product yields, and product properties is important to the successful solution of the problems encountered in the development of a satisfactory process. Statistical methods were used to design the experiments and analyze the effects of the rate of shale throughput, the composition of dilution gas, the height of the shale bed above the air entry, air-gas distributor design, shale size range, and the ratios of the flow rates of the various gas streams entering the retort to the rate of shale throughput.

Jan 1, 1960

By Joseph A. Holmes

The investigations carried on at the fuel-testing plant of the United States Geological Survey at St. Louis in 1904-1907 included tests of the steaming and gas-producing qualities of many coals and of the possibilif3 of their improvement by briquetting, together with washing and coking tests and tests of some of the resulting coke in the cupola. These tests were part of a general inquiry into the manner of utilizing most efficiently each of the coals under investigation. The equipment used in the cupola tests of coke, the manner of conducting the tests, and the essential results have been described in publications of the Geological Survey," and only the more important conclusions to be drawn from the tests are mentioned in the following pages. The tests were made to show the fitness of the cokes for foundry purposes, but an incidentlll result was to show foundry men and the coke producers the advisability of studying the conditions of foundry practice. The present bulletin, published by the Bureau of Mines because the analyzing and testing of fuels have been transferred from the Gilological Survey to the Bureau of Mines, briefly reviews the status of the coke industry, some features of practice in the use of coke in the foundry, the probable happenings of a cupola heat, and the reasons for modifying charging practice so that a particular coke can be used to best advantage.

Jan 1, 1910

By E. A. Barrett

The U.S. Bureau of Mines (USBM) conducted experiments to determine if training using a latent-image, three-dimensional (3-D) slide simulation exercise improved miners' ability to recognize roof and rib hazards. The effectiveness of this innovative type of classroom training was investigated by measuring workers' performance on a hazard recognition task. The study was unique in that hazard recognition skills were assessed in the workplace using actual coal mine roof and rib hazards. Results showed that training with a latent-image, 3-D slide simulation exercise significantly improved each subject's performance on the in-mine hazard recognition task. Further, the USBM researchers concluded that transfer of learning from the classroom to the workplace occurred.

Jan 1, 2010

By R. L. Hopkins

Fifteen alkyl cycloalkyl sulfides and three dicycloalkyl sulfides were synthesized to provide reference compounds in the search for these classes of sulfur compounds in crude oils. In synthesizing sulfides by alkaline alkylation the order in which the reactants were added was shown to determine the yield and purity of the product.

Jan 1, 1966

By Richard H. Otto

Three longwall mining methods practiced in foreign countries are described that have potential for increasing underground recovery and productivity in thick coalbeds of the Western United States. The methods are multislice long-walling, longwall caving, and high-face longwalling. Foreign practice and possible application in the United States are discussed.

Jan 1, 1979

By Oliver Bowles

The manufacture of lime is one of the oldest industries. Plants are distributed widely and furnish an essential raw material for numerous industries. The use of lime by the building trades, in agriculture, and in hundreds of manufacturing and chemical processes has created demands for a large production and has necessitated exhaustive research on methods of manufacture and uses. The bibliography of lime is an extensive one, but for the most part each publication has dealt with only certain operations. The purpose of this paper is to present a general picture of the industry as a whole. The abundant literature has been abstracted and quoted freely, and the National Lime Association has rendered valuable assistance in furnishing data for certain sections. Publications containing more detailed information on the various branches of the industry are referred to in the footnotes and in the bibliography.

Jan 1, 1936