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Control dust generated during overburden drilling at surface coal mines using either wet suppression or dry collection systems. Approach For the wet suppression systems, a range of water flow rates was tested over a number of holes. Each hole was drilled at a specific and constant flow rate. A recording flow meter was mounted in the water line near the control system pump. For the dry collection systems, each drill was tested with the front of the shroud set at different heights above the ground. Because of the irregularity of the ground surface, all height measurements were taken at the front of the shroud. Background Wet drilling systems consist of a water tank mounted on the drill from which water is pumped into the downhole air line. The water droplets in the bail air conglomerate dust particles as they travel up the the annular space of the drilled hole, thus controlling dust as the air bails the cuttings from the hole.

Jan 1, 1987

By Ernest L. Corp

The natural marine environment can be divided into four basic categories: the air-sea interface, the water zone, the seafloor, and the subbottom. Efforts are being made to accumulate data to delineate the conditions in each of these areas and to conduct engineering studies which will determine how these environmental parameters affect the mining process. Laboratory facilities have been constructed and equipment and techniques for scientific data collection and laboratory research have been developed. Major emphasis is being placed on studying the subbottom material. The objective of this emphasis is to study the engineering properties of marine placer deposits in order to assess their influence on the design and performance of the various mining subsystems involving penetration, excavation, transportation, and disposal. Presented are the results of engineering properties tests on a placer simulant which is currently being used for model and prototype testing of coring tools. The effect of these engineering properties on penetrability, core recovery, and sample recovery is discussed.

Jan 1, 1970

By James Rowland

On June 1, 2004, the underground coal mine ventilation safety standards under the Code of Federal Regulations (Title 30, Part 75) became effective for the use of a conveyor belt entry as an intake air course to ventilate working sections. These standards, also known as the Belt Air Rule, contained a section which limited the air velocity in the conveyor belt entry to no greater than 500 feet per minute unless otherwise approved by the US Mine Safety and Health Administration in the fire suppression system section of a mine?s ventilation plan. The Belt Air Rule included a requirement dictating compatibility of air velocity with fire suppression systems. The final rule of limiting air velocity in the belt entry was challenged in the Court of Appeals for the District of Columbia Circuit. The court granted that petition and vacated the requirement on the air velocity cap, according to MSHA. The removal of the air velocity cap from the final rule, paired with the compatibility requirement, led to a need for research on high air velocity?s influence on fire suppression system performance in belt entries. Test data was needed that illustrated the relationship between fire suppression system performance and air velocity, especially with the increased use of wider belts in underground coal mines, so National Institute for Occupational Safety and Health and MSHA collaborated to obtain the data. However, this work was initiated before the revised Belt Air Rule was promulgated on December 31, 2008, when 1000 fpm air velocity became a requirement. Four different

Jan 1, 2009

By R. Ward Stahl

Fire has been one of man's most useful tools through the ages and certainly is a "must" for industrial progress but when uncontrolled is one of the most destructive agencies. This fact is even more important in a coal mine, where many persons and much expensive equipment are confined in a relatively small area. Means of escape from a burning area, as well as from the products of combustion, are often limited; and in many instances the entire surroundings are combustible. Numerous mine fires, which resulted in a high death toll and great financial loss through the years, have caused mine owners to search for the best fire-fighting equipment; much of this has been installed, the quantity depending largely upon the experience of the individual companies or neighboring mines in certain coalfields. A mine owner or operator has meager published information on the actual fire protection afforded and systems of fire-fighting inaugurated in the coalfields, by which he could compare his efforts and get some idea of the adequacy of his own protection. To further general knowledge of the subject, it was decided to survey a representative number of mines in the field and show what has been accomplished. Representative mines were selected in various coal beds; some had similar tonnage, so comparison could be made if desired.

Jan 1, 1957

By J. T. Schimmel

The purpose of this investigation was to obtain complete information on some of the uses of a 24-inch-diameter auger in the underground mining of pitching anthracite beds. The auger was placed in operation early in 1958 to drive ventilation connections between coal gangways driven by a continuous miner. Although designed to drill rise holes only, it was used also to drill dip holes. The latter holes were drill id from an adjacent gangway to avoid interference between the auger and the continuous miner. These holes established immediate ventilation returns when intersected by the continuous miner. Bureau participation in the project covered 361 working days. The auger was used on 288 shifts, usually one 7-hour shift per day, and drilled 3,246 feet, of which 493 feet were reamed. The longest hole was 87 feet; hence the maximum drilling depth of the machine (rated at 100 feet) was not required. Holes drilled normal to the strike of the bed ranged from 30 to 66 feet deep, averaging 45 feet. The continuous miner drove gangways on 575 shifts. Thus, the auger worked one shift for each two worked by the continuous miner and was used on less than 80 percent of the workdays. The auger drove 24-inch holes 10 times faster than the larger, conventional openings could have been driven by usual mining methods and exceeded the workload for which it was purchased. Augering eliminates exposure to the hazards encountered in driving chute-work by conventional methods and provides adequate circular ventilation openings, which are strong in self support and are adaptable to reaming when required. With alterations, the auger may have limited use as a production machine in thin-bed pitch mining but cannot compete with established methods of thick-bed pitch mining.

Jan 1, 1962

By P. L. Woolf

Oil was successfully injected into the tuyeres of the Bureau of Mines experimental blast furnace. Determinations were made for the minimum oil addition necessary to permit the maximum available blast temperature of 2,250° F. and the maximum oil rates at blast temperatures of 1,900°, 2,000°, and 2,100° F. From these tests, the upper and lower levels of high-temperature heat input, which limit the smoothly operating furnace, were established. Substantial coke saving was realized with maximum oil injection. Oil-to-coke replacement ratios have been calculated for various conditions, and oil is compared with natural gas and moisture in somewhat general terms. A study of the effect of variations in slag volume and basicity on the sulfur content of the metal at high sulfur loads was made.

Jan 1, 1963

By Janet Torma-Krajewski, Pauline Lewis, Paul Gust, Lisa Steiner, Kean Johnson

Since 1990 and the publication of the Ergonomics Program Management Guidelines for Meatpacking Plants by the US Occupational Safety and Health Administration, numerous reports of companies implementing ergonomics program have been published. However, despite these numerous reports, no examples of implementing an ergonomics program in the mining industry have been reported. In 2000, NIOSH initiated a long-term project to demonstrate the implementation of an ergonomics process designed to identify and reduce exposures to ergonomic risk factors found in mining. The mine selected for this project was the Jim Bridger Mine, a surface coal mine located 35 miles northeast of Rock Springs, Sweetwater County, WY. This paper discusses how a large, surface coal mine implemented an ergonomics program and the lessons learned while doing so.

By D. S. Kingery

The data obtained from this study cover test areas that are gassy to ultragassy and pillared areas of different sizes and degrees of tightness. The methods of controlling ventilation, applying bleeders, and supporting bleeder entries varied in the different test areas. It was not possible to study all conditions likely to be encountered in coal mines. Undoubtedly, there are areas where bleeder entries, even though properly planned and maintained, might prove unsatisfactory. However, on the basis of this study, the following observations were made: 1. Tests showed that each bleeder system studied provided some movement of air through the pillared area; the quantities of air delivered to the pillar line, ranged from 23 to 82 percent, depending mainly on the extent to which bleeder re-turns were used as main returns from the section. 2. Pressure measurements taken across pillared areas showed maximum pressure drops ranging from 0.05 inch of water for a shallow gob to 2.69 inches for a very deep gob. The pressure differentials varied with the size and tightness of the gob but proved adequate to induce airflow across worked-out areas or through fringes of the gob to the bleeder return system.

Jan 1, 1957

Provide a central source of subsidence reference in formation for industry, academia, and government agencies interested in improving subsidence prediction and analysis under U.S. mining conditions. Approach Develop a comprehensive bibliography about mining related surface subsidence and store this information in a computer file. Make specific references accessible through a key word retrieval program. Supplement these key word identifiers by entry of author's name, title of publication, subject of text, or sponsor of publication. How It Works Requests for subsidence in-formation are made by phone or mail to the Bureau of

Jan 1, 1982

By L. W. Higley

Particulates generated in electric furnace (EF) steelmaking constitute approximately 1 to 2 pct of the charge. This flue dust is a rich source of zinc (values are substantially higher than in ore), but although there are several processes for recovering the metal, none are considered economic in the United States. This report reviews extraction technology and presents results of Bureau of Mines reduction-volatilization tests on pelletized EF dusts which achieved high recoveries of zinc. The data are sufficiently encouraging to warrant consideration of EF dusts as raw material for primary zinc smelters.

Jan 1, 1977

By L. J. Prosser, G. Esterhuizen, A. T. Iannacchione

The potential for roof fails in underground mines remains a clear and present danger for mine workers An investigation of ground conditions in nearly 50 percent of the nation’s underground stone mines fold that the slate of roof stability is primarily determined in a limited and subjective manner. These large-opening mines with roof heights typically 7 m (23 ft) or more, make physical observation difficult. Although some mines use monitoring techniques to gain additional information an roof stability, this practice is usually short term and localized to address ground conditions in a particular section or part of the mine. A roof-fall hazard-assessment techniques was development based on engineering judgment acquired from extensive underground stone mine experience and on exanimation of the related literature. This technique utilizes observational processes to determine roof fall likelihood Case-study scenarios offer a realistic picture of model implementation. Providing the mine level decision-maker with an accurate assessment tool to ascertain the level of ground fall hazards is expected to reduce mint worker injuries and fatalities Moreover; the presences of danger can be overcome with a clear picture of quantified ground conditions.

By Elaine T. Cullen

Educating the public about the role of mining and minerals can be a challenge. While it sometimes seems that little is being done to counteract negative publicity, there are many exciting things happening across the country that are helping meet this challenge. This paper will discuss existing minerals education activities and will provide tips for developing successful programs for a variety of groups, from students to industry to minerals educators themselves. The paper will also include an overview of the 9th annual National Minerals Education Conference held in July 2000 in Spokane, WA.

By Edward A. Mihok

This paper presents plant design and cost estimates for limestone treatment of acid mine water covering a wide range of quality and quantity conditions. The treatment process consists of limestone neutralization, aeration, solids settling, and concentration. The design criteria for the various operation functions are based on pilot plant performance, laboratory data, and established mine water treatment standards. Unit costs have been assumed and are related to general market prices and conditions. These estimates serve as preliminary indicators of what it would cost to construct and operate a mine water treatment plant.

Jan 1, 1970

By D. Litton, H. Dobroski, J. G. Kovac

Since 1910, the U.S. Bureau of Mines (USBM) has investigated practical ways of dealing with the consequences of major fires and explosions in underground mines. The results of this research have had a significant positive impact on the mining community by enhancing mine workers’ chances of surviving an underground mine disaster. Today, the Bureau continues to conduct research in mine disaster mitigation. Much of this work has direct application to search and rescue situations, such as: emergency evacuation through smoke-filled or otherwise unbreathable atmospheres, locating and rescuing survivors from rubble piles, and fire fighting in confined spaces. Three USBM research areas are discussed: (1) Life Support -- This effort is directed toward research into and development of closed-circuit breathing apparatus for use in hazardous environments which are likely to be encountered in the aftermath of a mine disaster. (2) Trapped Miner Location -- A mine disaster may result in the entrapment of miners whose normal escape routes are cut-off. This research activity resulted in the development of transportable seismic technology that can be used to locate trapped miners. (3) Mine Fire Diagnostics -- This research involves developing practical techniques for remotely monitoring how the atmosphere inside a mine changes during a fire, in order to estimate the spread and severity of an underground fire. This information is critical in deciding how best to fight a mine fire, or whether it is safe to mount a rescue and recovery mission.

Measure the leakage through individual crosscut stoppings quickly and economically so that the worst ones can be identified and repaired. (Typically 60 to 80% of the air supplied to a mine short circuits before reaching a working face.) Approach Most of the leakage through a permanent stop-ping is channeled through two windows in a temporary stopping, and air velocities through the windows are measured; leakage is determined from a formula. How It Works A temporary stopping made of plastic brattice is erected in the same cross cut as the permanent stopping, either upstream or downstream. The brattice is fastened to the roof, bottom, and ribs of the entry with spads. Normal leakage of brattice was allowed for in deriving formula, and does not effect results. For best accuracy the brattice and the stopping should be separated by a distance of one hydraulic diameter.

Jan 1, 1979

By J. N. Tomlinson

Trailing-cable splices are evaluated for moisture exclusion abilities after repeated travel over shuttle-car sheave wheels. Tests are conducted on cables with jackets made of neoprene, cholrosulphonated polyethylene (CSPE), and nitrile butadiene-polyvinyl chloride (NBR-PVC) to 50° C. The results show that some splice kits are effective as received, others are improved with minor but significant changes, and still others must be redesigned to be effective in underground applications. Laboratory results are compared with actual underground splice results. Recommendations for cable preparation prior to splicing are presented.

Jan 1, 1979

To develop a cost-effective tool for improving the performance of rock drilling systems used in detecting and delineating underground mine voids and for coal exploration. Approach To investigate admixtures of polyethylene oxide (PEO) at zero surface charge concentrations as drilling fluid additives to enhance penetration rates and extend bit life in rock drilling systems. Background Bureau researchers have investigated the use of chemical additives to enhance drilling performance and found that the most efficient drilling occurred when the drilling fluid was able to maintain a zero surface charge (ZSC) on the surface of the rock being drilled. Laboratory drilling studies have been performed on rock types such as quart¬zite, granite, taconite, and marble. The lab tests were conducted using 5/8-inch diameter diamond-impregnated coring bits with cationic compounds as the surface charge neutralizing additives. These studies demonstrated enhanced drilling performance, however, only at the singular additive concentration that produced the ZSC condition.

Jan 1, 1991

By Thaddeus B. Evans

This information circular is one of a series describing mining methods and costs, being published by the Bureau of Mines. The Sunbright mine of the Foote Mineral Co. at Sunbright, Va., is the southernmost underground limestone mine in the State. It is a comparatively recent operation, and a description of its rapid development to production stage may have particular interest for the limestone-mining industry. ACKNOWLEDGMENTS Acknowledgment is made to the executives of the Foote Mineral Company including F. B. Shay, vice president in charge of production, W. B. Towner, general production manager; and to the members of the company staff at Sunbright for their assistance in preparing this paper.

Jan 1, 1957

By M. M. Tilman

The Bureau of Mines conducted research to evaluate superplastic behavior in commercial magnesium-base alloys AZ6IA, ZK60A, ZW3, AZ3IB, ZWI, and an experimental Mg-12 pct Al alloy. Strain-rate sensitivity indices (m-values), maximum elongations, and effects of superplastic elongation on tensile properties were determined on fine-grained sheet. Inert-gas-pressure hemisphere-forming tests were conducted on selected sheet stock of the five alloys. Formability trials on AZ31B alloy sheet were conducted on industrial equipment for comparison with commercial superplastic forming of Zn-AI alloy. Closed-die-forming tests were performed on extruded ZK60A rod. All alloys exhibited well over 100-pct elongation, indicating superplasticity, at temperatures and strain rates near the maximum m-values. Tensile properties were generally reduced following 100-pct superplastic elongation, but not to an extent that would preclude use of the commercial alloys in the superplastically deformed condition. The potential for industrial superplastic forming of AZ31B sheet was indicated by hemisphere forming in the laboratory and substantiated in industrial forming trials.

Jan 1, 1982

Provide optimum visibility of mining operations while maintaining protection and comfort for machine operators. Approach A cab with hydraulically powered variable-height control was developed and used on a loading machine in underground operations. How It Works The cab is attached to the vehicle on a horizontal trunnion located near the forward end of the cab. A hydraulic cylinder, controlled by the operator from inside the cab, pivots the cab about the trunnion providing variations of up to 16 inches in elevation. The nominal tramming position of the cab is with its underside 6 inches above the mine bottom. From this position the cab can be pivoted up, or down, so that its back end is elevated 10 inches, or lowered to the floor. (See Figure 1.) The cab encloses the operator for protection against both overhead and lateral obstructions, and it raises or lowers, allowing the operator to select the most advantageous cab height. The cab is angled inboard 30 degrees to the machine line of direction. The operator's seat swivels to allow view of the conveyor during loading. All controls are located within the cab and move up and down with it.

Jan 1, 1978