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By C. W. Owings, F. E. Cash

"Transportation of explosives in mines is extremely hazardous, and where electric haulage is employed the danger is intensified. Insulated mine-car couplings have been adopted by at least five companies in Alabama and Pennsylvania - and undoubtedly in other States - to prevent an electric current passing from a mine locomotive to a car or between care joined by this coupling. The need for such protection is recognized in the report of an explosion.""Four hundred kegs of black blasting powder had been loaded into four mine cars at the railroad, to be hauled to the magazine, upgrade, by a trolley locomotive. On starting, the motorman put sand on the rail and a grounded circuit passed through the hitchings and so exploded the powder. No insulation was used between the locomotive and cars."" When used on man trips the insulated coupling further serves the purpose of guarding the men against shock. Four couplings are described so that a clearer understanding may be obtained of the details of construction.ConstructionThe general principles of construction are similar in all insulated couplings. The piece containing the hole for the coupling pin is made of steel and the steel parts are separated by an insulating material, such as fiber or wood. The coupling is either rigid or semirigid to prevent the bumpers of the mine cars from coming in contact and to keep the cars insulated from one another at all times."

Apr 1, 1928

By Jürgen F. Brune, R. Karl Zipf, Kenneth L. Cashdollar

This paper outlines the legal standards and methods for protecting underground coal mines in the United States from explosions of methane gas and coal dust. It will discuss inspection and monitoring of mine atmospheres, dilution of methane through ventilation, methane drainage prior to, during and post-mining, as well as explosion prevention through rock dusting and sealing of mined-out areas. Recent research findings of the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory on the magnitude of pressures obtained during methane explosions from modeling and full-scale explosion tests at the NIOSH Lake Lynn Experimental Mine will be presented. This work is currently being applied to modeling the structural response of explosion-proof mine seals to pressures from gas explosions. Also, new research will be presented on the inertization of float coal dust in mines through the addition of inert stone dust and on the application of the Coal Dust Explosibility Meter (CDEM), a handheld device developed by NIOSH to directly measure the explosibility of a coal dust - limestone dust mixture based on optical reflectivity.

By R. J. Hundhausen

The continued worldwide shortage and strategic value of nickel place great importance upon the continued development and exploitation of new sources of nickel in the United States, The deposits of nickel-bearing minerals in Oregon and Washington have attracted considerable attention, particularly since the Hanna Development Co. has engaged in development work aimed at producing ferronickel from the Nickel Mountain deposit, near Riddle, Douglas County, Greg. The Red Flats nickel deposit in Curry County, Oreg., was first examined by the Bureau of Mines in dune 1945, but it was not until 1952 that the deposit was drilled and sampled. In 1953, a 15-ton sample of Red Flats material was procured and subjected to continuous smelting tests in the Bureau's Northwest Electrodevelopment Laboratory, Albany, Greg.

Jan 1, 1954

1. In 2002, a total of 256 metal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Metal mines were the smallest mining sector,1 comprising 1.8% of all mining operations. • Gold mines comprised 44.1% (n = 113) of all metal mining operations. Other types of metal mines were copper ore (n = 31; 12.1%), iron ore (n = 25; 9.8%), and lead and/or zinc ore (n = 21; 8.2%). • Nevada is the state with the largest number of metal mines (n = 53; 20.7%).

Jan 1, 2004

By Burke Cartwright, S. F. Ravitz, Lloyd R. Michaels

This method is similar to the reduction of dolomite by ferrosilicon, in that it does not require the direct use of electrical energy; like ferrosilicon, the calcium carbide must be produced in an electric furnace, so that the reducing agent in both processes may be considered in some respects as “stored” electrical energy. The reduction of magnesium chloride by calcium carbide is exothermic, takes place rapidly at ordinary pressure and at relatively low temperatures, and can be carried out in ordinary steel equipment, whereas the reduction of dolomite by ferrosilicon and the carbothermic reduction of magnesium oxide are endothermic, require high temperatures, and present serious problems with respect to materials of construction. Because of its apparent simplicity and other advantages, the Bureau of Mines has briefly investigated the reduction of magnesium chloride by calcium carbide. Published data on the reduction of magnesium chloride by calcium carbide are meager. Matignon states that reduction is fairly rapid at 1,200º C. Matsuura claims that magnesium chloride is not reduced by calcium carbide at atmospheric pressure and 800º C; however, by keeping the pressure under 10 mm. of mercury he was able to obtain small globules of magnesium at 800º C.

Mar 1, 1947

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

1 14 THIS IS A DIGITAL COMPUTER SIMULATION OF THE VENTILATION SYSTEM OF A MINE LOCATED IN WASHINGTON COUNTY, PENNSYLVANIA. THE VENTILATION SURVEY ON WHICH THIS SIMULATION IS BASED WAS RUN FROM OCT. 27-30 AND ON NOV. 2, 1976 IN THE ACTIVE PORTION OF THE MINE INBY COMBS SHAFT AND THE INACTIVE PORTION AFOUND AND INBY DONAHOO SHAFT. FOLLOW-UP SURVEYS WERE THEN RUN ON FEB. 18 AND FROM MARCH 7-11, 1977 TO INCLUDE THE MAIN HAULAGE SYSTEM OUTBY THE ACTIVE AREAS OF THE MINE. ALL SURVEY DATA WAS NORMALIZED TO A STANDARD DENSITY OF 0.075 POUNDS/CU.FT. PRIOR TO THE CALCULATION OF INPUT PARAMETERS FOR THIS SIMULATION. IN THIS RUN, THE ORIGINAL VENTILATION NETWORK HAS BEEN MODIFIED TO INCLUDE NEW INTAKE AND RETURN AIRSHAFTS AT THE WEST MAINS. IN ADDITION A CONNECTION HAS BEEN MADE BETWEEN THE MINE UNDER STUDY AND A SHAFT IN A WORKED OUT MINE IN THE 1 FACE AREA. THIS SHAFT IS CONSIDERED AN INTAKE SHAFT FOR THIS RUN.

Jan 1, 1977

By R. H. Sprute

Hydraulic backfill consisting of siliceous mill tailings was successfully dewatered and consolidated by electrokinetics in a field test conducted by the Bureau of Mines at the Star mine, Burke, Idaho. A stope at the 2,000-foot level was filled in such a way that slimes and coarse sand were retained in the scope. Following settlement of solids and decant of surface water, direct current applied between buried electrodes created a firm, dense material in approximately 3 hours. This rapid densification of fine-grained material demonstrated the utility of this method and suggests other applications, particularly in the control of slime deposits that cause serious problems in many deep mines.

Jan 1, 1975

By D. R. Tesarik, R. W. McKibbin

Material properties affecting slope stability were measured in a large 50-year-old, partially consolidated rockdump located in an active open-pit mine. Field tests included single-ring infiltration and density. In addition, a nuclear depth-moisture gauge was used to measure water content in six stainless-steel-cased drill holes on the crest and an upper bench of the rock dump. Precipitation, evaporation, wind speed and direction, and temperature data were collected at a weather station installed on the dump’s crest. Laboratory tests included particle-size distribution, specific gravity, Atterberg limits, and water content. By measuring material properties of a rock dump presumed to be stable, the safety of miners working on or at the toe of old rock dumps constructed of similar material and located in a similar climate can be assessed.

Jan 1, 1999

By J. J. Rutledge, C. A. Herbert

In 1916 the Bureau of Mines, the Illinois Geological Survey, and the University of Illinois, working under a cooperative agreement, began an investigation of the subsidence of the surface above coal- mining operations. Four widely separated places where mining was in progress were selected as observation stations-one in the northern Illinois longwall coal field, one in the central Illinois coal field where the room-and- pillar panel system of mining was being used, and two in the thick coal of southern Illinois where the room-and-pillar panel system of mining was employed. These four points of mining activity gave a rather wide opportunity for observing subsidence when different mining methods were used. The four places selected for investigation of surface subsidence due to coal mining have been designated as follows: 1. A, in the northern Illinois longwall coal field, where the coal company has been operating coal mines for 30 years and where long- wall advancing is the only method of mining. 2. B, in Perry County, where panel room-and-pillar mining of a thick seam of coal is in progress and where mining operations have been carried on about 40 years. 3. C, in Macoupin County, where the coal company has been min- ing coal by the panel room-and-pillar method for about 15 years. 4. D, in Franklin County, where the coal company has been mining coal for 10 years by the panel room-and-pillar method.

Jan 1, 1927

By Thomas G. Carnahan

The Bureau of Mines conducted research to simulate in situ leaching of a chalcopyrite ore. The purpose was to obtain a direct comparison between moderate-temperature and elevated-temperature in situ leaching of copper trom minus la-inch ore and to analyze the sulfuric acid and oxygen requirements of the leaching system. Experiments employing oxygen were conducted at 35° and 90° C on 362-and 367-1b ore charges, respectively, under flooded conditions and at 400 psig. At 90° C, 47 pct of the copper was extracted in 913 days of leaching; at 35° C, 27 pct of the copper was extracted in 915 days. Diffusion into and out of the ore fragments con-trolled the rate of leaching. Oxygen consumption was 1.46 lb/lb of copper extracted at 35° C and 3.15 lb/lb of copper extracted at 90° C. Sulfuric acid requirements of the ore were 5.49 and 7.48 lb/lb of copper extracted at 35° and 90° C, respectively.

Jan 1, 1982

By G. F. Kuncir

The funding tables included in this report were defined in support of an evaluation of the Advancing Oil Sale Mining Technology Program undertaken by The Aerospace Corporation. Because of the sensitive nature of the fiscal planning information, the tables have been separated from the main analysis report and given a limited distribution.

Jan 1, 1977

By J. H. Heginbotham

As part of the total metallurgical system to recover metals from secondary resources, the Bureau of Mines conducted froth flotation research, using cationic reagents to recover glass from urban refuse. Batch flotation tests showed that high-quality cullet can be obtained from glass-rich aggregates derived from municipal incinerator residues and unburned refuse. This was confirmed by pilot plant operations treating 350 pounds of flotation feed per hour. Aggregates containing 85 to 90 percent glass were wet-ground to minus 20 mesh, deslimed in two stages, and fed to flotation cells. The glass was selectively floated using an amine collector, usually in an amount under 0.2 pound per ton of solids in the feed. The glass concentrates from the rougher cells were cleaned by refloating two or three times. Over 90 percent of the glass in the deslimed feed was recovered in the cleaned concentrates.

Jan 1, 1978

By F. C. Gregory

"Introduction.The third annual mine-rescue maneuvers of the Globe-Miami District First Aid and Mine Rescue Association were held at Globe, Ariz., on November 5 and 6, 1923. The first demonstration was held in October 1922, and the results** from that experiment, both in the practical training and the interest aroused in the apparatus men, were so much more satisfactory than those from the ordinary smoke-chamber training, that Orr Woodburn, director of the Association, decided to hold similar maneuvers at frequent intervals. The second test was held on March 21-22, 1923, in connection with the meeting of the Southwest Mining Section of the National Safety Council at Globe.Place and Organization.The recent maneuvers were held in the same mine and conducted in the same general manner as the first, and the points of interest not brought out previously are described below. By studying the accompanying map the movement of the teams can be better understood.Thirty-three apparatus men were out on the first day and thirty-two on the second day, a total of forty-three men being trained.Mr. Woodburn was aided in directing the work by his two assistants from the mine-rescue station, two local safety engineers, and an engineer from the Bureau of Mines. Local mine superintendents and the State deputy mine inspector were interested spectators."

Jan 1, 1924

By R. J. Matetic

The National Institute for Occupational Safety and Health (NIOSH) has recognized that Noise-Induced Hearing Loss (NIHL) is the most common occupational illness in the United States. The use of heavy equipment, the drilling of rock, and the confined work environment are some of the factors that contribute to high levels of noise exposure to workers in the mining industry. Every day 80% of the nation’s miners go to work in an environment where the time weighted average (TWA) exceeds 85 dBA. Moreover, 25% of the miners are exposed to a TWA noise level that exceeds 90 dBA, the Permissible Exposure Limit (PEL). Furthermore, a NIOSH analysis of a large sample of audiograms showed that at age 50 approximately 90% of coal miners and 49% of metal/non-metal miners have a hearing impairment. By contrast, only 10% of the non-occupational-noise exposed population has a hearing impairment at age 50 (Franks, 1997) (Stephenson, 1998). Simply stated, the majority of miners have a hearing loss by the time they retire. While NIHL is the most common occupational disease in this country, this problem is especially acute among workers in the mining industry. There are several barriers to reducing NIHL in the mining industry. These include: gaps in knowledge of noise dose/source relationships, the unavailability of effective noise controls, and needs for worker education and worker empowerment. A related issue is the difficulty of communication in noisy workplaces by both hearing impaired and normal hearing workers. The Pittsburgh Research Laboratory (PRL) at NIOSH has strategically developed a hearing loss prevention program for overcoming these respective barriers in an attempt to reduce NIHL in the mining industry. This paper provides an overview of the research program being conducted at the PRL.

By Ronald D. Hill, Elmore C. Grim

Some of the terms defined here are not used in the text. However, the terms will be useful to those interested in this and other publications in the field of coal surface mining.

Jan 1, 1974

This Bureau of Mines report summarizes the research, development, and evaluation demonstrations conducted by the Bureau of Mines under the Health and Safety Act of 1969 to improve the means of notifying miners underground, who are away from their own phone, that they are being called.

Jan 1, 1977

By Rad B. Langston, Ted J. Williams, John A. Marjerison, Rimas T. Pakalnis, Tom M. Brady, Doug C. Bayer, Mark J. Bren

Underhand cut and fill mining methods are used at the Lucky Friday, Stillwater, and Galena mines in the western US in an effort to safely mine in difficult ground conditions and as a primary mining method where access below the ore is limited. The method has evolved at each mine to meet the unique situations associated with their milling procedure and mine layout. Details of the operational aspects of the backfilling and mining cycles at each mine are presented in this paper, accompanied by a summary of the mechanical properties of the backfill and its in-situ geomechanical behavior.

By J. F. Barkley

As part of the work of serving as Chairman of Subcommittee 3, Health and Industrial Requirements, of the American Society of Mechanical Engineers' Committee on Air-Pollution Controls, the author assembled the following information on accepted maximum permissible concentrations of air pollutants from the standpoints of health, damage to vegetation, damage to property, and requirements of industrial processes. A search in technical literature was made followed by direct inquiry to all State governments as to their regulations. The subcommittee membership - G. D. Clayton, senior sanitary engineer, Public Health Service, United States Department of Health, Education, and Welfare, Detroit, Mich., Dr. L. Greenburg, commissioner; Department of Air Pollution Control, New York, N.Y., Dr. M. Katz, Defence Research Chemical Laboratories, Ottawa, Ontario, Canada, and Dr. H. H. Schrenk, research director, Industrial Hygiene Foundation of America, Inc., Mellon Institute, Pittsburgh, Pa. - reviewed the information and made very helpful comments and corrections.

Jan 1, 1954

By Donald O. Capstick

A mineral survey of a 13,525-acre portion of the 21,875-acre Owyhee Canyon Wilderness Study Area in northern Nevada was conducted by the U.S. Bureau of Mines in 1984. Two samples from sand and gravel deposits in the study area contained minor placer gold typical of the Owyhee River area. The gold-bearing gravels are too low grade or of insufficient volume to support commercial placer mining operations. The sand and gravel deposits might have minor local construction uses.

Jan 1, 1986

By J. P. Baur

The sensitivity of radiochemical techniques makes possible the study of the initial-stage sulfuric acid leaching kinetics of chalcopyrite and other copper sulfide minerals. This Bureau of Mines study of the initial leaching of chalcopyrite used techniques to evaluate the molecular and electrochemical processes. High-grade Transvaal chalcopyrite was neutron-irradiated in a TRIGA reactor4 to produce radioisotopes copper-64, iron-59, and sulfur-35. Dissolution rates were measured in the time interval zero to 60 minutes, during which time significant anomalies were observed. First was an initial period of rapid dissolution lasting a few minutes; second, an arrest or ?plateau? region usually lasting from 6 to 10 minutes; third, a second period of dissolution of lesser rate than the first. The effects of solution variables such as pH, oxygen partial pressure, and ferric ion concentration at different temperatures were measured.

Jan 1, 1974