Search Documents

By Robert J. Timko

Water-jet-assisted cutting involves the use of a mechanical cutting bit in combination with a high-pressure water jet directed just in front of the bit tip. Such a jet can offer benefits in terms of improved cutting, reduced dust and fines, and improved bit wear. The Bureau of Mines, through a contract with the British National Coal Board, has re- searched the use of water-jet-assisted cutting on roadheaders. After several engineering design problems were overcome, this program led to the successful underground testing of these roadheaders. Today, more than 60 water-jet-assisted roadheaders are in operation around the world, and numerous others are on order. This paper details the evolution of these machines and the benefits to be gained by their use.

Jan 1, 1986

By E. J. Ostrowski

The Bureau of Mines experimental blast furnace, Bruceton, Pa., was operated to determine the feasibility of replacing part of the burden coke requirements with solid fuels injected directly into the smelting zone. This report describes preliminary experiments and information resulting from such an interchange. These experiments were made on an all-sinter burden, using two parts sinter to one part fuel. Anthracite fines were injected intermittently into the smelting zone of the furnace by compressed air through auxiliary tuyeres. The interval between injection periods ranged from 5 to 15 minutes. A maximum of 28 percent of the stock column coke bur-den was replaced. This percentage replacement caused furnace malfunction, but the overall percentage of these experiments indicated that 20 to 24 percent of the coke requirements could be replaced in this way. The metallurgical coke consumption was decreased by as much as 377 pounds (25.3 percent) per ton of pig metal produced. Buckwheat anthracite No.4 was used in this experiment; however, such solids as bituminous coal or coke fines also could be used. The frequency as well as the quantity of solid fuel injected has a direct bearing on furnace performance.

Jan 1, 1960

By B. H. Eccleston

The Bureau of Mines, in cooperation with the American Petroleum Institute, studied the effect of fuel volatility and front-end fuel composition on the amount and photochemical reactivity of automobile exhaust and fuel-system evaporative emissions. The study involved six gasolines--the base fuel, three fuels of varied volatility, and two fuels differing from the base and from each other in front-end olefin content. Data were obtained from 16 vehicles operated on a chassis dynamometer using a speed-load-time cycle that approximated a typical urban trip. Tests were made at ambient temperatures of 20°; 45°, 70°, and 95° F, using a climate-controlled dynamometer room. The amount of hydrocarbon emission and its probable photochemical effect, a potential contribution to pollution, is expressed as weight (reactivity equivalent) of a moderately reactive material, ethylene. Emissions of oxides of nitrogen, car-bon monoxide, and aldehydes were also observed. Results showed that reduction of volatility from currently typical levels serves to reduce both the amount and the reactivity equivalent of evaporative losses with a slight penalty by way of higher exhaust emissions. Alternatively, reducing the amount of light (low boiling) olefin in the fuel had no effect on the amount of hydrocarbon pollutant but did significantly reduce the reactivity equivalent of the emissions. Neither volatility change nor chemical changes to the fuel significantly affected the nonhydrocarbon emissions.

Jan 1, 1970

By David A. Benjamin

In 1989 and 1990, the Bureau of Mines conducted a mineral resource investigation of the 122,000-acre Trinities study area, located in the Trinity Mountains of south-central Idaho. No identified mineral resources were delineated during this study. There are 58 lode mining claims within the area. Five localities contained elevated metal concentrations which may indicate precious metal mineralization at four localities and molybdenum-precious metal mineralization at another. Four of the five localities appear to form a northwest trend through the center of the study area. Twenty-eight individual sites contain anomalous concentrations of gold, silver, bismuth, molybdenum, and beryllium.

Jan 1, 1991

By Daryl E. Radcliffe

Ninety-seven roof bolts were instrumented with strain gages and resin-grouted in three areas of the Bear coal mine, Somerset, Colo., by the Bureau of Mines. Measurements taken with these instruments indicate roof support is achieved through a combination of point suspension and resistance to vertical and horizontal stresses caused by localized shearing in the roof. The localized shearing results in bending of the bolts, yielding due to high vertical stresses, and the transfer of high loads to the bolt head or plate.

Jan 1, 1980

By Karl C. Dean

The Bureau of Mines studied the precipitation of copper from dilute acidic sulfate solutions using shredded automobile scrap in a rotary drum. The tests established that the scrap in the rotary drum precipitated copper faster and more completely than shredded, detinned, tinplate scrap in a launder, with comparable iron consumption. Although power is required to rotate the drum, the faster precipitation and continuous recovery of cement copper are advantages of the tumbler method. Cost evaluation indicates that the rotary drum method, which uses relatively low-cost and readily available shredded automobile scrap, is competitive with the launder method, which uses relatively high-cost shredded tinplate scrap or detinned shredded cans.

Jan 1, 1968

By Andrew B. Cecala

The Bureau of Mines conducted laboratory and in-mine tests on the Racal airstream helmet (Model #AR21) to evaluate its protection efficiency. Laboratory tests indicated that as ambient air velocity increased, the protection offered by the helmet decreased. In tests conducted at several coal mine long-wall sections with face velocities under 400 fpm, the helmet was 84 pct effective at reducing respirable dust in the miner's breathing zone. However, at a high-velocity section, 1,200 fpm, the efficiency of the helmet was significantly reduced, confirming our laboratory results.

Jan 1, 1981

By W. W. Adams, V. E. Wrenn

"Production of explosives in the United States during the calendar year 1936, as represented by reports of sales by manufacturing companies, totaled 391,604,500 pounds, an increase of 27 percent over the amount produced during 1935. This quantity included 81,698,375 pounds of black blasting powder (granular and pellet), 262,047,106 pounds of high explosives other than permissibles, and 47,859,019 pounds of permissible 5/ explosives.The manufacturers' reports to the Bureau of Mines classify the sales of explosives according to five main classes of work in connection with which the explosives were used.Coal mines used 87 percent of the total amount of black blasting powder sold, bituminous-coal mines 79 percent, and anthracite mines 8 percent; coal mines also consumed 98 percent of all permissible explosives and 9 percent of the high explosives other than permissibles. The coal-mining industry consumed 16 percent more explosives in 1936 than in the preceding year, the increase at bituminous mines being 21 percent and that at anthracite mines 4 percent.Metal mines used 29 percent of the high explosives other than permissibles and less than 1 percent of the black blasting powder and permissible explosives. The total quantity of the three classes of explosives used in metal mining in 1936 was 36 percent more than the quantity so used in 1935."

Jul 1, 1937

By C. A. Herbert

"Haulage accidents usually are responsible for about 17 or 18 percent of all coal-mine fatalities and about 21 percent of all non-fatal coal-mine accidents. When the relatively small number of employees continuously exposed to haulage hazards is considered, it would appear that haulage is more hazardous than any other phase of coal-mine operation.Haulage accidents have increased from year to year, doubtless due to the increase in electrical haulage, and particularly to the use of larger cars, heavier locomotives, longer hauls, and greater speed. Unless very definite steps are taken to eliminate the causes of these accidents, they will continue to increase rather than be reduced, as they can and should be.Underground haulage in many of the large modern mines of today is similar in many respects to railroad practice. In recent years the railroads have made wonderful strides in reducing accidents, and instead. of being one of the most hazardous occupations, as it once was, railroading is now one of the safest. Doubtless, if thought and action, similar to that given to reducing accidents among railroad passengers and employees, were given to safety in mine haulage, under¬ground haulage accidents could be reduced in about the same ratio.Haulage accidents may be classified, according to responsibility, into two groups - those for which management is largely responsible and those for which the employee is largely to blame; there is, however, an overlapping of responsibility from one group to the other. If, therefore, haulage accidents are to be reduced, it is absolutely essential that both management and employees cooperate to this end.In the first group, for which management is largely responsible, may be included accidents due to faulty equipment, moor track, a poorly arranged system of haulage, lack of clearance or of overhead protection, and dirty roadways; even in these features, however, the employee is not without a measure of responsibility, as failure of haulage equipment possibly may be due to lack of care on his part, failure to report when equipment is out of order, or failure to do a good workmanlike job of installing or repairing or operating.To the second group of accidents for which the employee may be largely responsible, belong those caused by such careless practices as jumping on and off fast-moving trips, coupling on the ""fly"", running at excessive speeds, failure to properly block cars, and similar hazardous and unnecessary acts of omission or commission. If, however, management condones such practices, or, as in some instances, insists upon them, it must accept its share of responsibility for the accidents that inevitably result.Some of the most prolific sources of haulage accidents will be discussed briefly, together with the steps that may be taken to minimize their occurrence."

Oct 1, 1939

By R. H. Grau, S. B. Robertson, F. Garcia, A. C. Smith, T. P. Mucho

Researchers working for the National Institute for Occupational Safety and Health (NIOSH) at the Pittsburgh Research Center are developing ways to protect the health of miners. Part of that effort is improving the air quality in metal/nonmetal mines by developing proper ventilation techniques. The air quality of large opening nonmetal mines can be greatly improved by using engineering controls of contaminant prevention and proper ventilation techniques. Contaminant prevention includes methods to reduce contaminants from entering the mine air. Ventilation can be improved with appropriate fan selection and fan operation used in conjunction with air coursing using manmade and insitu rock stoppings.

By W. D. Monaghan, G. L. Mowrey, C. W. Ganoe

In addition to developing various types of coal-interface detection system, the US Bureau of Miner is actively in involved in developing a coal rib-thickness monitoring system for highwall mining applications. One particular system that shows promise in a ground-pentetrating radar system to detect the coal-air boundaries of coal rifts. Based on preliminary laboratory and field tests results indicate that this method can be applied successfully in highwall mines to maintain constant rib thickness. The coal seam should be relatively clean in the vicinity of the antenna (e.g., have minimal partings or dirt bands) for best results.

By Oliver Bowles

[In an endeavor to promote greater efficiency in the lime industry, the United States Bureau of Mines is preparing a series of preliminary reports dealing with particular problems of the industry. Through the circulation of these reports, it is hoped that sufficient interest may develop among lime-plant operators to prompt them to discuss with the bureau their our experiences with these problems. By such an interchange of ideas, it is believed that conclusion may be reached which will be of practical benefit to try entire industry. The first report, "Stripping problems it Limestone quarries of the Shenondoah Valley", Serial No. 2401, was issued during October, 1922. This report t is the second of the series. It is hoped that may operators will contribute additions to the information now at hand.]

Jan 1, 1922

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 Martin H. Stanczyk

Two methods of recovering zinc from zinc ammonia complex solutions were investigated. One method studied was distillation of the ammonia from the solutions to recover a basic zinc sulfate, which after calcining to zinc oxide was reduced to metallic zinc using hydrogen at 900° C. The second method tested was electrolysis. The tests were made of synthetic and leach solutions analyzing about 80, 100, and 115 gpl (grams per liter) of Zn, NH3, and SO4, respectively. The leach solutions were prepared by oxidation leaching of a sphalerite flotation concentrate, assaying 55 pct zinc at elevated temperature and pressure. The distillation method recovered about 98 pct of the zinc in a product analyzing 97 pct zinc. Ammonia losses incurred during the leaching and distillation operations were about 0.1 lb per lb (pound per pound) of metallic zinc produced. Electrolysis of the solutions at a cathode current density of 25 amp per sq ft (ampere per square foot) yielded zinc deposits assaying in excess of 99.9 pct zinc. About 1.5 kwhr (kilowatt-hour) of power were consumed per pound of zinc deposited; the current efficiency was 72 pct. Other electrodeposition tests revealed that small amounts of ferric iron in the cell liquor were deleterious to electrolysis unless about 5 lb of glue per ton of zinc were present in the electrolyte. The use of glue and vigorous agitation of the electrolyte gave smooth zinc deposits from solutions containing as much as 0.1 gpl iron.

Jan 1, 1962

By Henry E. Blake

The purpose of this Bureau of Mines investigation was twofold. The first phase of the work was to determine the technical and mechanical feasibility of defluorinating low-grade siliceous fluorspars on an intermediate scale by high-temperature pyrohydrolysis in a rotary kiln. The second phase was to react the liberated hydrogen fluoride (HF) offgas with alumina monohydrate to produce commercial-grade aluminum fluoride (85 percent AIF3). The two phases of the work were to be integrated into a single continuous process. Evaluation of the data shows that low-grade siliceous fluorspars can be successfully defluorinated, either in a solid or a molten state, in a gas-fired rotary kiln in the presence of water vapor at 1,250° to 1,350° C. The water produced by combustion of propane was sufficient to yield defluorinatians of 75 to 85 percent.

Jan 1, 1962

[ ]

Jan 1, 2012

By D. E. Ingersoll

This report describes the preparation characteristics of anthracite from the Mammoth and Holmes veins in Schuylkill County, Pa., as determined by the Federal Bureau of Mines laboratory separations at specific gravities of 1.50 to 1.90. The Holmes vein anthracite contains approximately 13 percent ash, and the Mammoth vein contains about 9 percent as fed to the breaker. Crushing Broken, Egg, and Stove sizes from each vein produces Pea-size anthracite of lower ash content than that contained in Buckwheat No.1 size and smaller. The Buck-wheat No.5 size has the highest ash content of all the sizes examined. Potential recovery from a mixture of the two veins as received at the breaker, separated at 1.90 specific gravity, is approximately 64 percent of the feed at 11.0 percent ash. The same materials separated at 1.80 specific gravity yield about 61 percent with an ash content of 10.1 percent. All rejects are from the Holmes vein, because the entire Mammoth material is less than 10.0 percent ash.

Jan 1, 1960

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 G. C. Reed, J. A. Herdlick

The Blackbird district, Lemhi County, Idaho, has long been recognized as a potential source of cobalt and copper. Exploration of the early discoveries in the area was largely discouraged by the comparatively low grade and small size of the known ore bodies, the slight demand for cobalt, and the lack of adequate roads throughout the region. Recent advances in the field of alloy metallurgy culminated in a steadily expanding demand for cobalt. This demand was finally accentuated to critical proportions in 1940 by worldwide rearmament programs and by the threatened disruption of foreign imports by submarine warfare.

Feb 1, 1947

By M. J. Ackerman, C. R. Waine, W. M. Merritts, L. P. Mokwa

Tests were conducted in the Pocahontas No. 4 coalbed in southern West Virginia to determine if successful degasification techniques, developed during an earlier study in the Pittsburgh coalbed, would be effective in removing methane from those usually more gaseous coals. Specially designed long-hole drilling equipment and Bureau of Mines continuous recording devices were used to measure the quantity and methane content of the ventilating air during the investigation. Infusions were made with water at normal waterline pressures ranging from 200 to 220 psi or at pump pressures ranging from 400 to 650 psi. Results of the tests showed that methane emissions from free-flow bleeder holes were as much as 131 cfm. Infusions of some of the holes increased the methane emission from other holes and from the exposed coal surfaces near the working areas as much as 1,540 cfm. The methane content in the main return-air currents after infusion was reduced more than 86 percent of the amount recorded before tests were made.

Jan 1, 1963