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By J. C. Franklin

The Spokane Mining Research Center of the Federal Bureau of Mines is placing major emphasis on chemical stabilization as part of the ground support program. Development of polymeric material suitable for bonding rock fractures around the mine opening is one phase of the program. Some of the problems that must be considered are viscosity, applicability, adhesion, cure times, strength, toxicity, and flammability. Epoxies and polyesters were investigated, but shrinkage in polyesters caused redirected effort toward epoxies. Test results with the latter showed that bonded fractures in mine-roof strata were stronger than the virgin rock. Further tests showed that polymeric materials have good potential for bonding, and in conjunction with polymer roof bolts, are expected to result in an economic and useful new support concept.

Jan 1, 1974

By J. D. Hadden

The Bureau of Mines conducted drilling studies in the Pocahontas No. 3, the Pittsburgh, and a western coalbed to establish the gas migration characteristics for each. Gas pressures in the Pittsburgh coalbed were about 260 lb/in2 and in excess of 550 lb/in2 in the Pocahontas No. 3. Caving in drill holes prevented pressure measurements in the western coalbed. The Pittsburgh coalbed contained intersecting "clay veins" which formed gas pressure cells. Although these geological features hamper mining, they can be used to control the flow of methane into a mine working. Methane control techniques are proposed for the Pittsburgh and Pocahontas No. 3 coalbeds.

Jan 1, 1969

By William L. Crentz

This Investigation of the preparation characteristics of the coals in Armstrong County, Pa., is the third in a series of Bureau publications by counties appraising the practicability of upgrading marginal deposits to metallurgical standards. Earlier investigations covered the washing characteristics of the coals occurring in Cambria County, and the principal reserves remaining in Indiana County. In Armstrong County, the Upper Freeport bed is the major source of production, the Lower Kittanning bed being of secondary importance. The Lower Freeport bed is mined to some degree, but it is usually too thin and spotty in occurrence to support large-scale operations. The remaining production is taken from the Pittsburgh, Middle Kittanning, and Upper Kittanning beds, but the quantities are insignificant. Table 1 shows the county's coal production) by beds, during 1948. The coals of Armstrong County are not generally considered to be of metallurgical quality because of the high sulfur content. The raw coals usually analyze more than 2 percent sulfur, and more than 4 percent sulfur is not uncommon, especially in the Lower Kittanning bed.

Jan 1, 1951

By Wing G. Agnew

The drilling and bit-sharpening practice in the southwest Wisconsin zinc district generally conforms to the procedure described herein, except at very small properties, where drill steel is sharpened by hand. Though hot milling of rock-drill bits is practiced in South Africa on some of the large-scale operations, it is seldom seen at American minus in any form. Because of the simplicity and low cost of the equipment, it was thought that a brief description might prove interesting to same of the operators in ether districts who do not have enough steel to sharpen to warrant equipping an elaborate sharpening shop.

Jan 1, 1936

By Wallace W. Roepke

The Bureau of Mines has a well-established health and safety research effort directed to fundamental studies of the mine cutting system. This report describes the ignition danger of using cutting bits with flat wear area on still-intact carbide inserts.

Jan 1, 1983

By Wilbur L. Webb

An electrically powered methane sampling system for application on mining machines was designed, fabricated and laboratory tested. The system will sequentially draw sample air at a controlled rate from up to three machine positions across the mine face and deliver the air to either an approved methane monitor, methanometer or flame safety lamp. The prime considerations in the design were to provide an intrinsically safe, water and dust resistant control box and an explosion-proof power box capable of being operated from the various mining power sources. The power box contains an internal battery that provides operating power prior to mining machine start-up and alter machine shut-down. The internal battery is recharged automatically when mining machine power is available.

Jan 1, 1977

By Liane L. M. Kacinuck

This U.S. Bureau of Mines publication is intended to provide mining industry representatives and regulatory authorities with a reference package dealing with studies on hydrology and underground mine subsidence. An annotated bibliography and a list of additional sources are given and represent references published prior to June 1993. Ninety-two references ware identified and 72 obtained for assessment. Annotating the references included evaluating the study methodology and summarizing the basic results. The references are also compiled based on geographic location to aid the user in identifying articles of particular interest.

Jan 1, 1994

By Larry R. Wilson

The development effort described herein was directed toward the design and development of a flexible communication system to provide two-way section communications between any telephone on an MCM-101 telephone FDM exchange and a miner provided with a uhf walkie-talkie transceiver. The system also provides normal communication between miners within a working section through the uhf coupler interface repeater.

Jan 1, 1976

By Bernadette C. Michalski

THE RAPID GROWTH of the small Albanian mineral industry in the 1950's began to taper off by 1961 and slackened sharply in 1963. The abandonment of Soviet and East European technical assistance programs in mid-1961 greatly affected Albania's mineral development, since four-fifths of all technical aid personnel were engaged in mineral activities. Chinese assistance apparently has not been able to fill the void. Overall mineral production increases during 1961-63 averaged 1 percent per year in value, as compared with 3 percent in 1959 and 5 percent in 1960. Although by world standards Albanian mineral output, except for chromite, is insignificant, it is vital to the country's domestic economy. The mineral industry generated about 14 percent of the gross industrial product in 1962 and employed a notable share of the industrial labor force. In recent years, mineral products have provided about three-fifths of the country's exports by value. Chromite and iron-nickel ores together constituted from one-fourth to one-third of the total export value. In 1963, total trade turnover increased 12 percent over 1962.

Jan 1, 1964

By T. W. Johnson

The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past several years the flow of natural gas through high-pressure pipe lines. This report deals with that part of the study involving the design off pipe-line systems consisting of lines laid parallel to each other. The lines are referred to as the original line and the parallel line. The paralleling line may or may not extend the entire length of the original line; however, the parallel line is connected at its two ends to the original line. As a result of the large expansion of the natural-gas industry almost all markets within economic distance from the developed gas fields have at least one pipe line supplying them with natural gas. Small increases in the consumers' demand for natural gas can be met usually by increasing operating pressures, but any marked increase in demand necessitates paralleling sections of the existing systems. It is believed that to a large extent future

Jan 1, 1934

By J. L. Shultz

The Bureau of Mines extended its investigation of methanation catalysts. The noble metals (platinum, palladium, ruthenium, rhodium, osmium) and rhenium), molybdenum, and tungsten were tested in hydrogenations of carbon monoxide and carbon dioxide at 21 atmospheres in a temperature range between 200° and 600° C. From the 8 metals studied) 25 catalysts represent 5 catalyst types were prepared and tested. The impregnated 0.5-percent-ruthenium catalyst proved to be the most active and versatile of all the catalysts produced. Tungsten and the noble metals other than ruthenium were low in activity and usually required temperatures above 500° C for appreciable production of hydrocarbons. Molybdenum was moderate in activity, but further improvement in molybdenum catalysts seems possible.

Jan 1, 1967

By R. Hogg, E. Kaya

"The presence of agglomerated particles in airborne dust in coal mines has been confirmed by SEM examination of static samples collected on substrates. In addition, the effect of agglomerated particles on the performance of cascade impactors and cyclone-type personal samplers has been studied. Simple procedures have been developed for evaluating the extent of agglomeration in air-borne dust by comparing the observed size-selectivity of the sampling devices with that expected under idealized conditions. Applications of these techniques in the laboratory and in underground mines are discussed.INTRODUCTIONAirborne dust is invariably present in mine atmospheres. Particle size is a primary factor in determining the behavior of the dust, its effects on miners' health and the effectiveness of dust control measures. Obviously, agglomeration of the dust particles can have important effects on: ""natural"" dust removal processes such as settling• the use of water sprays etc., for dust control• pulmonary deposition characteristicsIn addition, the presence of agglomerates could influence the effective toxicity of the dust. For example, ultrafine particles are often thought to be relatively unimportant in the development of respiratory ailments because of their low deposition efficiency. However, the latter could be substantially increased if such particles were present in larger agglomerates. It is by no means obvious that there should be significant agglomeration of the airborne dust in a mine atmosphere. In fact, calculations based on the classical coagulation theories indicate that, at the kinds of dust concentrations that exist even in what would be regarded as “very dusty"" atmospheres, the coagulation half-time* .should be of the order of weeks or even months. On this basis, agglomeration would be expected to be essentially negligible. On the other hand, laboratory experiments (Polat et al., 1991) have revealed very extensive agglomeration in the airborne dust released during the crushing of individual coal and mineral particles. It is postulated that such agglomeration occurs immediately at the point of dust generation. In other words, many of the fine fragments produced on fracture are never completely separated from their neighbors."

Mar 1, 1992

By James J. Scott

Eleven workshops were held in various locations throughout the country in an attempt to reach the many diverse groups working in various mineral commodity areas and special ties. These meetings were held between March 1, 1974 and June 25, 1975. They were held under the auspices of the Bureau of Mines Contract to the University of Missouri-Rolla which was designed to help define Bureau research and development priorities. At each workshop a summary of current Bureau research and development was presented and the attendees were asked to present their ideas on what Research and Development programs should be undertaken to meet their needs locally. Participants included representatives of federal and state agencies, educational institutions, mining companies, equipment companies and other interested parties. The workshops covered under this report include lead mining in Missouri, limestone mining, coal mining both surface and underground in the midwest and in the Rocky Mountain area, iron mining in Minnesota, two top management meetings on institutional problems and, finally, a special two-day meeting on roof control.

Jan 1, 1977

By Frank Chase, M. Terry Hoch, George Karabin, Joseph C. Zelanko, Christopher Mark

Pillar recovery continues to be a significant ground control hazard. During the past decade, 10 miners were killed during pillar extraction operations in southern West Virginia. Studies conducted during the past decade have identified a number of “risk factors” that can be used to evaluate pillar extraction plans: •Cut sequence •Final stump •Timber or Mobile Roof Supports •Roof bolting •Intersection span •Depth of cover •Roof quality •Age of workings For each of these factors, rock mechanics science suggests which alternative would be expected to be more risky. For example, numerical models were used to evaluate different cut sequences, and indicated that less roof convergence occurred with the outside lift method than with the Christmas tree in the particular environment simulated. For many of the risk factors, accident statistics confirm the science. One finding was that currently almost 70% of the retreat coal in southern WV is being mined with MRS. In contrast, timber supports were used in 70% of the past decade’s pillaring fatalities. This paper discusses each of the risk factors in turn, presents the relevant accident statistics, and shows how the risk factors can be combined to estimate the overall hazard. It also addresses the use of pillar design to minimize the risk of global stability hazards including squeezes, massive collapses, and bumps.

By Donna lynne Anderson

This report documents the status of a laser-based underground guidance system for tracking and controlling the movements of underground mobile mining equipment. This research is part of a multiple project effort at the U.S. Bureau of Mines to increase mine safety and efficiency by developing technology for computer-assisted mining. Guidance systems, which can track and control the movements of underground mining equipment, are essential during computer-assisted mining operations. A continuous mining machine at the Bureau's surface test facility served as the test-bed for initial development and experimentation of this guidance system. Subsequently, a continuous mining machine in an underground mine served as the platform for in-mine experimentation The first section of this report includes details of the laser sensors, communication network, and computer hardware. The next section includes experimental results, which show the system capable of accurately tracking and controlling the tram maneuvers of a continuous miner underground. The final section discusses conclusions and recommendations.

Jan 1, 1992

By Welby G. Courtney

The Bureau of Mines conducted a field test program in the Pittsburgh coal seam to investigate the effect of water sprays in the suppression of respirable dust being formed while cutting with a continuous-mining machine. Emphasis was given to the location of spray nozzles on the top and bottom of the cutting boom. Results showed that (1) sumping caused about 60 percent of the dust escaping the face area, and shearing and loading caused the other 40 percent; (2) during sumping, top and bottom sprays were equally effective in dust suppression and reduced dust ~13 percent; (3) during shearing and loading, bottom sprays reduced dust 61 percent and were about 50 percent more effective than top sprays; (4) the combination of top and bottom sprays was slightly more effective than the separate systems, but water consumption increased 60 percent; and (5) inclusion of throat sprays decreased dust reduction by removing some of the water from top and bottom sprays where it was more effective.

Jan 1, 1978

By H. V. Makar

The Bureau of Mines successfully demonstrated, on a pilot plant scale, a sodium sulfate (Na2S04) refining process for removal of copper from molten ferrous scrap. Previous tests established technical feasibility on a bench scale for achieving low copper concentrations and determining the principal factors controlling process efficiency. The pilot plant study involved a 1-ton arc furnace for melting ferrous scrap and a 1-1/2-ton treatment ladle. Results of these tests showed that copper removals obtained in laboratory tests (approximately 40 relative percent copper removal with 10 weight-percent surface addition of sodium sulfate) could be achieved on the pilot plant scale when excess carbon was added with the sodium sulfate compacts. Data were obtained on temperature losses and carbon consumption related to Na2SO4 treatment.

Jan 1, 1974

By Roy E. Peterson

The Bureau of Mines conducted bench-scale research to evaluate materials which showed potential as low-cost reductants for use in the ironmaking industry. These materials were lignite, subbituminous coal, coal char, tree trimmings, refuse--derived paperboard, used crankcase oil, and peat. To compare their effectiveness, the materials were tested in the reduction roasting of nonmagnetic taconite and, except for oil and peat, in the reduction of iron oxide pellets to metallized pellets. Reduction was conducted in a 18-cm-diameter, rotary drum, which was externally heated in an electric furnace. Over 92 pct of the iron was magnetically recovered from a nonmagnetic taconite after roasting with any of the reductants, but greater quantities of reductant were required to achieve this when the waste materials were used. The fossil fuels were also more effective for metallizing pellets, although metallizations above 90 pct were also obtained with tree trimmings and refuse paperboard. However, refuse paperboard had to be frequently recharged to the furnace because it depleted rapidly.

Jan 1, 1983

By Clyde E. Williams

[As a results of work conducted during the past three years, the Northwest Experiment Station of the Bureau of Mines, in cooperation with the University of Washington at Seattle, Washington, has developed a process for the production of sponge iron. Commercial operation of this process in a 3 to 4-ton scale has been so satisfactory that its use on a large scale (20 to 100 tons per day) can be safely considered. Description of Process. The process consists in passing a mixture of iron ore and coal through a rotating kiln heated at one end to a temperature sufficient to convert iron oxide to metallic iron, discharging, cooling, and separating the sponge iron from the residual coke and silicious material on a magnetic separator. Both the coal and the ore should be crushed to peso as 6-meth scream, tans producing particles finer then 1/12 of an inch. Seventy-five parts of coal or other carbonaceous material arc charged with every 100 parts of ore), This large amount of coal is required in order to supply sufficient carbon to maintain a strongly reducing atmosphere in the charge, but may be reduced to about 65 parts per 100 parts of ore by recovering and using tae carbon that remains in the discharge product. Large-scale operation and refinements in furnace design should lower this ratio to perhaps 56 or 60 parts of coal to 100 parts of ore.]

Jan 1, 1924

By Gerald T. Homce, James C. Cawley

Electrical arcing injuries are the most common form of electrical injury in mining. MSHA data show that 381 "non-contact electric arc burn" injuries occurred in the mining industry from 1996 - 2005. A more detailed study of data from 1990-2001 showed that five types of apparatus - circuit breakers, conductors, nonpowered hand tools, electrical meters and test leads, and connectors and plugs were involved in two-thirds of the lost workday injuries. Many of the protections from electrical arcing injury available to workers in other industries stem from the application of National Fire Protection Association Standard 70E - Standard for Electrical Safety in the Workplace (NFPA 70E). NFPA 70E is a generally accepted industry guideline document, but excludes underground mining from its scope. Many of its practices and procedures, however, can be applied in the mining workplace to supplement the existing electrical safety requirements of Title 30 Code of Federal Regulations. This paper describes how NFPA 70E can be applied to mining workplaces after an analysis of the mine power system electrical arcing hazards has been completed (and Hazard/Risk Categories determined) using the tables from NFPA 70E or the calculation method as described in IEEE 1584. NFPA 70E can then be used to determine the levels and types of personal protective equipment (PPE) needed to protect miners against burn injuries. Appropriate lockout and tagout (LOTO) procedures for use in the mining industry are also described. Suggestions for better selection of electrically-rated hand tools are included. Recommendations for electrical meter selection and use based on transient withstand capability are also discussed.