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Roof falls continue to be the greatest single safety hazard faced by underground coal miners. During 1996-99, 44 coal miners lost their lives in rock falls, and nearly 2,400 were injured. In addition, nearly 6,000 noninjury roof collapses were reported. Roof supports are installed to protect the miners, but support system failures contributed to most of these incidents. Reducing the terrible toll taken by ground falls continues to be a major goal of research by the National Institute for Occupational Safety and Health (NIOSH). The purpose of these proceedings is to provide the mining community with a comprehensive survey of coal mine roof supports. Drawing on many years of research undertaken by the NIOSH Pittsburgh and Spokane Research Laboratories, this volume describes what types of support are available, how they work, and when they should be used. The major subjects covered include roof bolts, standing roof supports, cable supports, and longwall shields. Some special topics are also addressed, including an analysis of roof fall accident statistics, techniques for better skin control, material handling considerations, and longwall mining through recovery rooms. This proceedings volume also contains information on several important new technologies, which are described here for the first time: •Guidelines for selecting roof bolt length, pattern, and capacity that were derived from statistical analysis of the roof fall experience at 37 underground mines; •A new design method for longwall tailgate supports; and •A technique for measuring loads developed within cable bolts. The papers in these proceedings were presented at open industry briefings conducted by NIOSH on New Technology for Coal Mine Roof Support. The briefings were held in Norton, VA, Charleston, WV, Evansville, IN, Tuscaloosa, AL, Price, UT, Glenwood Springs, CO, and Washington, PA. The papers were also presented at the Mine Safety and Health Administration (MSHA) Preventative Roof-Rib Outreach Program (PROP) Seminar, which was held at the National Mine Health and Safety Academy near Beckley, WV.

Jan 10, 2000

By J. E. Meacham

The U.S. Bureau of Mines investigated recovery of manganese from basic oxygen furnace (BOF) steelmaking slags because the slags represent a large potential resource of a metal for which there is no domestic production. BOF slags were leached using fluosilicic acid, a byproduct of the fertilizer industry. Manganese and iron were extracted as soluble manganous and ferrous fluosilicates while the calcium and magnesium remained in the tailings as insoluble fluorides. Treating the pregnant liquor with sodium chloride, precipitated sodium fluosilicate (Na2Sif6) which was recovered as a byproduct. Manganese and iron were precipitated as hydroxide-carbonate salts with the addition of sodium carbonate to the treated liquor. Recoveries for manganese and iron were 73 to 83 and 67 to 70 pet, respectively.

Jan 1, 1991

By William H. Schiffbauer

This paper details the computer hardware and software integrated to provide computer-assisted control and monitoring of four different coal mining machines. The backbone of each system is a U. S. Bureau of Mines integrated distributed microcomputer control network called BOM/NET. The network provides connections for intelligent sensors and systems that provide for navigation, diagnostics, and computer control. Many different computer systems using various operating systems (including RMX I, UNIX, VXWORKS, DOS and DCX51) have been connected to the network and each have had complete network functionality. A description of the network's integration to Joy' 16CM, a Joy 14CM, a Jeffrey 102, continuous mining machines, and a custom built auger machine is provided. The networks for the Joy 16CM, the Joy 14CM, and the Jeffrey 102 have been installed and extensively tested at the Bureau's surface test facility. The Jeffrey 102 system has also been tested in a highwall coal seam. The Joy 14CM will soon be tested underground.

By Robert C. Hickman

"INTRODUCTION The Big Four fault and the Sandy Creek fault, with several cross faults, traverse the Stalion-Curnel fluorspar prospect in a northeasterly direction. The Big Four mine, about three-quarters of a mile northeast of the prospect, is the only active mine in the immediate area.A resistivity survey was made of a portion of the prospect by the Division of Geophysical Exploration, Bureau of Mines, in May and June 1946. As a result of this survey, five holes were drilled by the Bureau of Mines during the period from October 8 to December 16, 1946. Two Longyear No. 12 Junior Straitline diamond drills were used for the work.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The project was under the supervision of Mitchell H. Kline, chief, Raleigh Branch, Mining Division."

Mar 1, 1948

By Erica E. Hall, Robert H. Peters, Charles Vaught, Jon C. Volkwein

Coal workers’ pneumoconiosis is the leading cause of death due to occupational illness among U.S. coal miners. This disease is caused by miners’ exposure to excessive levels of respirable coal mine dust. A personal dust monitor (PDM) has recently been developed to provide near real-time feedback to miners regarding the level of respirable coal dust in the air they breathe. The main objective of this report is to document coal miners’ reactions to this device and how they make use of the information it provides. It summarizes a field study by the National Institute for Occupational Safety and Health that documented the opinions of 30 miners at 4 underground coal mines concerning the use of PDMs.

Jan 2, 2008

By S. C. Tadolini, T. M. Barczark

Mines in the western United States have had limited choices for standing support. Wood cribs were often too soft and unstable. The introduction of the Can support in the earl v 1990s provided an effective alternative, (lilt/ it remains the dominant form of tail¬gate support. Water-filled prestressing cells are now used to cap the Can and preload it to provide an active roof load. The Cluster Prop, consisting of three timber wedge props bundled to¬gether; provides more capacity than (m equivalent sized Call support and improves transport efficiency. However the Cluster Prop is less stable and does not maintain a consistent load throughout its loading profile. Pumpable roof supports are another alternative support, but the \' have not been proven in high deformation en¬vironments. This paper compares the performance characteristics o f these various support systems.

By D. Harrington

"The fire boss in coal mining and the shift boss in metal mining, though held responsible to a large extent for safety of underground employees and of the mine, are, it seems to me, not always vested with sufficient authority nor given compensation commensurate with their duties. The metal-mine shift boss, although his position as regards his relations between employer and employee, is frequently an unenviable one, has as a rule much more authority than the fire boss and is not expected to perform the menial tasks required of the latter by many coal-mining companies.In most coal-mining States the coal-mine foreman and the fire boss are re¬quired to possess a certificate of competency obtained by passing an examination. The foreman is legally responsible for the safety of the miners, as in most instances the superintendent is not required to pass an examination. Although the foreman is held legally responsible for the safety of the miners, the law does not, in general, compel the superintendent or other higher officials to delegate sufficient authority to the foreman to enable him to put his wishes or judgment into effect; and this condition has tended in many instances towards perpetuation of unsafe conditions.The fire boss is held legally responsible for conditions in his ""beat"", but he is generally given only such authority as the mine foreman sees fit to delegate, frequently very little, Moreover, the fire boss is generally required to cover his ""beat"" within two hours before the entrance of the underground workers. Only too often his territory is so great that in order to reach all the working faces and chalk the required date at the face, he must travel at a rapid walk or even run. When such haste is necessary to cover the required ground, it is manifestly im¬possible for the fire boss to make a careful inspection or examination of the roof, timbering, wiring, gas, etc., at each place, and doubtless in his hurry many unsafe conditions escape his notice."

Sep 1, 1920

By Rimas Pakalnis, Ted Williams, Tom Brady, Wilson Blake, Mary MacLaughlin, Kathryn Clapp, Cristian Caceres, Mario Morin

This paper describes a focus of work presently being conducted at the Rock Mechanics Research Group at the University of British Columbia. The underhand method under consolidated fill ensures a high recovery under an engineered back that is comprised of cemented rock fill and/or cemented paste fill. This method of mining is generally necessary either due to a weak rock mass comprising the immediate back and/or high induced back stresses. A major concern in the design of sill mats is the loading and strengths associated with the overlying sill mat. This paper reviews past practice coupled with present observations and measurements from over ten (10) mines throughout North America. It outlines areas of concern in terms of design requirements.

By Fred N. Kissell

Experimental work by the Bureau of Mines indicates that when a coalbed is degassed by boreholes, the flow of methane may actually increase with time. This phenomenon appears to be the result of a relative-permeability effect; that is, the coalbed permeability to the gas increases sharply with decreasing water saturation. This report reviews the background of experimental evidence indicating a relative-permeability effect, and presents the results of a computer simulation of two-phase flow in coal.

Jan 1, 1975

By Dana Reinke, William Wiehagen, Launa Mallett, Charles Vaught, Kathleen M. Kowalski, Michael J. Brnich, Lynn Rethi, Lisa Steiner

Safety and health professionals from all sectors of industry recognize that training is a critical element of an effective safety and health program. A major concern in the mining industry today is how to train the present aging workforce plus the expected influx of new and less experienced miners and mine operators as the cohort of older workers retire. This paper defines the problem, offers a model to structure the inquiry, and presents the key issues a multi-disciplinary team of NIOSH researchers identified, based on an extensive review of the current literature in relevant areas. Issues include differences between cohorts, such as the newer workers (Generation M), and present workers (Boomers) with respect to their physical, social, psychological, and cultural characteristics, their learning styles and work expectations. Specific issues for an aging workforce are discussed. Some preliminary recommendations are offered on the type of training needed.

By W. M. Dressel

A simple field test for detecting the presence of germanium in rocks, coals, and flue dust has been developed by the Bureau of Mines. The method consists of dissolving germanium from the samples by either acid or fusion treatment methods, adding a few drops of hematein or phenylfluorone dye, and extracting the resulting colored complex with carbon tetrachloride. INTRODUCTION Germanium is obtained commercially as a byproduct of zinc production, as a coproduct of base-metal refining from germanium-bearing mineral, and as a recovered product from the ash of some coals. The growing use of germanium in the electronics industry has increased demand for this semiconducting metal to the extent that an intensive search for new sources of supply is necessary.

Jan 1, 1962

Native asphalt was produced by five companies in two States, Texas and Utah. Bituminous limestone, used primarily as a paving material for street and road repair, was produced by White Uvalde Mines and by Azrock Industries Inc., Uvalde County, TX. Gilsonite, a solidified hydrocarbon, found only in Utah and Colorado, was mined by American Gilsonite Co., a division of Chevron Resources Co. (a subsidiary of Standard Oil Co. of California), by Ziegler Chemical and Mineral Corp., and by Hydrocarbon Mining Co. (a subsidiary of Oberon Oil Inc., a Utah corporation) from properties in Uintah County, UT.

Jan 1, 1984

Provide a method of detecting and locating miners trapped underground following a mine disaster. Approach Develop a surface deployed system which senses the vibrations caused by a trapped miner pounding on the roof of the mine and effectively determines the miner's location. How It Works If trapped underground, a miner would strike the roof of the mine with any implement at his disposal. This pounding causes vibrations in the ground which are transmitted to the surface where they are sensed by receiving transducers called geophones. Multiple geophones are positioned together for noise cancellation purposes in a form called a subarray. Seven

Jan 1, 1981

By Scott Turner

To be successful , human exertion employed for the creation of value requires power and heat ; the ability to produce concentrated power in great quantities has resulted in the relatively recent industrial development that is so profoundly affecting the world . In our commercial history , we have advanced through several stages in the selection of the most suitable fuels , continuously striving to increase the flexibility and range of energy- transmission . The easy distribution of light , power and heat is the leading factor in the decentralization of industry which promises to correct some of the serious evils that have followed in the footsteps of our commercial development . The distribution of fuel in quantity in so convenient a form and with such an attractive reliability- factor as can be had with gas , meets the modern conception of efficient service . Natural gas has been used in this country for more than a century, but recently it has attained a prominence far in excess of anything known in its earlier history. We may consider that we are now getting into our real stride in the utilization of our natural- gas resources . : In a country like the United States , wherein we are accustomed to mammoth achievements , we may be inclined to accept casually the noteworthy technical and economic advances which have resulted in the expansion of natural- gas distribution . About three years ago , the transmission of natural gas a distance of more than 250 miles from its source was first accomplished , and this was really a noteworthy engineering feat . Today , this useful commodity is being transported twice that distance , and lines are being laid which will carry gas more than 900 miles from the points of occurrence . Let us not take such outstanding improvements too much as a matter of course ; the industry should be congratulated on its long steps forward .

Oct 1, 1930

By Julie Mitchell, Robert King, Len Eros

The Bureau of Mines has studied the Deserado Mine computerized monitoring and control system, located in Rangely, Colorado, to acquire knowledge about the overall costs and benefits of mine monitoring systems. The Deserado system is a complex system monitoring environmental parameters, electrical power, and operation of all mine equipment, and controlling the entire conveyor haul age system. This paper discusses the evaluation of the Deserado monitoring system from initial design through system installation and operation. It also examines the costs, benefits, and performance of the monitoring system.

By M. D. Schlesinger

Mercury exists in coal in minute quantities, but the large tonnages of coal consumed could represent relatively large amounts of mercury entering the environment. Limits have now been placed on the emission of mercury, and it is important that reliable analytical methods be available to the chemist. The Bureau of Mines has evaluated analytical techniques used by a number of laboratories; most used vapor phase atomic absorption as the final detection method. Neutron activation was used by some of the laboratories. All of the methods described could be applied, but they require careful manipulation to prevent loss or mercury contamination. In the samples analyzed the mercury content ranged between 0.05±0.01 and 0.4l±0.06 part per million.

Jan 1, 1972

By N. H. Snyder

Coal analyses help to describe the character of coal as it lies in the ground of as it may he delivered to the user Analyses of samples of coal collected from the face of the bed in mines are plentiful, but available analyses of delivered coal are relatively few, and there is a distinct difference between "mine samples" and "delivered samples.” Mine samples are collected actor drag to a standard method. 13 The sampler cuts a channel. 2 by 6 or 3 by 4 inches from roof to, floor in the face of the bed, and excludes from the sample all partings more than 3/8 inch thick, and any lenses or concretions of sulphur or other impurities more than 2 inches in maximum diameter and 2 inch thick. Analyses of mine samples form a permanent and scientific record of the coal bed at the point sampled, they ale important in determining the character of the coal in any given mine or district These analyses, when the samples are taken by a standard method, are valuable to the operator When compared with analyses of delivered coal they show him whether his mine is being worked efficiently or whether the coal is being properly prepared, which involves the ques¬tion ii Nether he has suitable mechanical appliances for separating the impurities sties. In the purchase of coal, mine samples may serve as a sufficient guide for the experienced buyer who has knowledge of the impurities in the bed, and the degree to which these are eliminated in mining and preparing the coal To the average purchaser, however, unacquainted with these details, dependence on mine samples may be misleading The quality of coal indicated by the base samples call rarely, if ever, be attained in the delivered coal Certain impurities that are eliminated from the formally prepared mine sample may not be eliminated by the miner Some of the roof and floor may also be included if these are soft or flaky When coal prices are high and competition is lessened it is easy for the miner and the management to lower the standards of preparation, and a return to rigid stand¬ards is always difficult. In sampling delivered coal the Bureau of Mines follows a definite procedure. 14 A sample of not leas than 1000 pounds is systematically

Jan 1, 1928

By Richard G. Geyer

One aspect of a program to improve the chances of survival following coal mine disasters is the development of a communications system which will allow surviving miners to make their circumstances known to rescue teams. Various communications techniques can be considered, including electromagnetic systems, acoustic systems, and hybrid systems. The electromagnetic and acoustic systems would be independent of existing mine communications systems and set up specifically for use in emergencies. Hybrid systems might use a short emergency link to existing telephone systems in the mine. Many variations are technically possible, and the primary task is in evaluating the relative merits of each, so that the most workable system can be selected.

Jan 1, 1973

By Robert W. Freedman

This report describes sampling and analytical procedures used for measurement of sulfates in diesel tailpipes and in the diluted exhaust within dilution tunnels. A variety of methods exist for sulfate analysis for such systems, including ion exchange. Two chemical methods used by the Bureau of Mines are described in detail. These are based upon spectrophotometric measurement of chloranilic acid using barium chloranilate. The procedures are rapid and relatively inexpensive. In general, ion exchange is preferred by many analysts for sulfate analysis. However, it is more complex and expensive than chloranilic acid procedures, which are adequate for exhaust analysis.

Jan 1, 1982

By Howard E. Parkinson

An environment monitoring and communication system has been installed in the Bruceton Mine, and research is under way to improve mine safety. Standard day-to-day mine communications are available, along with additional systems installed to permit experimentation with wireless radio, through-the-earth phones, along-the-roof paging, and mine face machinery communications. Research is continuing and the essential concepts for a dependable whole mine communication system, providing simple environment monitoring, improved day-to-day communications and post-disaster communications, will be demonstrated in a larger mine with about 900 feet of overburden.