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By William P. Diamond

Ventilation has long been the primary means of controlling methane emissions in underground coal mines. However, as mining has progressed into gassier areas of U.S. coal basins, supplemental means of methane control have become of interest, if not a necessity, for continued safe and productive mining operations. This paper describes the history and technology of methane drainage in the United States and other countries. The methane drainage technology developed in European countries is a valuable resource since their longer history of mining has already forced mine operators to deal with methane emission problems only now being experienced in the United States. Methods for assessing the need for methane drainage and the data required for planning and implementing an appropriate system are reviewed. The effectiveness of the various technologies for reducing methane emissions underground and/or the in-place gas content of individual coalbeds is illustrated with case studies. In addition to the safety and productivity gains to be realized from methane drainage systems, the potential for commercialization of coalbed methane is discussed.

Jan 1, 1994

By M. A. Lucas

The Bureau of Mines has developed a computerized mathematical model to predict the distribution of accessory elements throughout a metallurgical process. The model can be used to determine process conditions that effect better accessory element control consistent with continued high primary metal recovery. The model presented is specific for determining the bismuth distribution in lead smelting but can be adapted to most extractive metallurgical processes. Thermodynamic, kinetic, and process parameters form the base for the model. Its logic and structure are described in detail.

Jan 1, 1983

By S. J. Schatzel, J. Cervik, A. A. Campoli

The cross-measure borehole technique is being studied by the Bureau of Mines as an alternative to the use of surface gob boreholes as a means of controlling methane in gobs during longwall mining. Small-diameter holes are drilled from underground locations into strata overlying the mined coalbed. When the roof strata are fractured by the mining opera- tion, a partial vacuum applied to the boreholes draws the methane out of the fractured strata and prevents it from entering the mine ventilation system. Tests in the Upper Kittanning Coalbed showed that 50 pct of the methane produced by the longwall mining operation was captured by the cross-measure boreholes. Borehole inclination and penetration into the gob are two important borehole parameters that affect the performance of the cross-measure borehole system.

Jan 1, 1983

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

MINE VENTILATION NETWORK ANALYSIS

Jan 1, 1977

By E. L. Burwell

Application of the in situ recovery process to oil shale was tested during two field experiments near Rock Springs, Wyo. The results of these tests demonstrate that a self-sustaining combustion zone can be created in an oil shale body, that this zone can be moved through the oil shale, and that the process will produce shale oil. Evaluation of the combustion process by monitoring produced fluids for physical and chemical properties and volumes is described. The material and energy balance obtained is compared with a second evaluation based on extensive coring of the test area after the test was terminated. Several side results of the research are noted such as ground surface heating by underground burning and production of low-to medium-Btu gas during retorting.

Jan 1, 1973

By R. V. Subramanian

This project financed by the Bureau of Mines investigated the use of polymers to achieve rock bonding and reinforce coal mine structures for better or permanent ground support. Support was achieved by pumping the polymers into the rock interstices to bond the mass together for increased structural competence. Holes were drilled in the mine roof, after which the polymers were injected at about 100 psi to permeate the cracks. Initial laboratory work indicated that of all the resin systems tested, the epoxy resins could most likely be modified to be suitable for rock injection. This was confirmed when several potentially suitable resin systems underwent intensive evaluation. In a series of three field tests, two conducted in a copper mine with coal mine-type shale and the third in a coal mine, it was shown that the polymers penetrated cracks less than 0.005 inch wide. The fast-setting epoxy systems, cured out in thin films under mine conditions, produced a bond exceeding the strength of the uncracked virgin rock.

Jan 1, 1974

By T. M. Nasiatka

This report sterns from a study undertaken by the Federal Bureau of Mines to determine the possibility of reducing filter-cake moisture by applying radiant heat. Suitable laboratory equipment was set up to study the effect of heat, heating time, proximity of the heater to the filter cake, cake thickness, and other variables related to the final filter-cake moisture. A minus-48-mesh coal slurry and application of heat for 60 seconds resulted in filter-cake moistures 5.6 to 13.2 percentage points lower than could be accomplished by filtration alone at 24 inches of Hg for 1-1/4-and 1 1/2-inch cake thickness, respectively. The moisture reduction can be attributed to the combined effect of lower fluid viscosity and evaporation.

Jan 1, 1959

By I. N. Beall

The present survey indicates 'that the average volatility of motor gasoline now being marketed throughout the country falls well within the limits of Federal Specifications. As would be expected, there is a slight decrease in volatility as compared with the gasoline marketed last wine:., but on the average the gasoline sold today is about the same as that sold last summer. During the past five years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States. To obtain a sample of each gasoline sold is obviously impracticable, but the cities in which samples have been collected have been so chosen as to be representative of the more important marketing territories. It is believed, therefore, that the samples obtained are indicative of the quality of gasoline marketed throughout the country.

Jan 1, 1925

By Dean E. Bluman

The Bureau of Mines investigated the convective heat transfer coefficients for recirculated suspensions of 30-micron glass beads in inert gas. Coefficients for the suspensions were not significantly higher than coefficients for the pure gas. Reynolds numbers of the suspensions were 20,000 to 35,000; solids loadings ranged from 0.0 to 0.7 pound per pound of gas. Comparison of the results with published data showed the direction of heat flow to have no effect at the test conditions.

Jan 1, 1967

By P. R. Tisot

The structural response of propped oil shale fractures was determined for each of two different grades of Green River oil shales (38.0 and 29.0 gpt) as they were heated in an inert atmosphere from ambient to subretorting temperatures (below those required for rapid pyrolysis of the organic matter). Small oil shale cores were propped apart by 3-mm glass beads to simulate a small cross section of a propped oil shale fracture between an injection and a producing well. These specimens were then heated at a uniform bate up to 800° F in a specially designed test cell under stress levels from 100 to 1,000 psi in biaxial and in triaxial confinement. Under the conditions of heat and compressive stress utilized in this study, all of the propped fractures in the two oil shales underwent structural deformation ranging from partial to complete collapse, as evidenced by proppant embedment. Structural collapse of induced fractures would in turn result in serious impairment or complete loss of the fracture flow capacities of the specimens. Results from this Bureau of Mines study indicate that underground retorting of Green River oil shale may be seriously impaired by loss of permeability when utilizing propped fractures in oil shales assaying more than 28 gpt.

Jan 1, 1975

By Donald P. Mickelsen

The raining and quarrying trends data shown in this report were reported to the U.S. Bureau of Mines (USBM) by mining and quarrying companies on the Mine Information Supplement survey, as well as by mineral producers on 58 annual USBM production and consumption surveys covering 59 nonfuel mineral commodities. The 1993 data presented in the tables of this chapter, were processed for the first time using the USBM Automated Mineral Information System. Domestic mining of nonfuel mineral materials totaled 3.7 billion metric tons in 1993, including 2.2 billion tons of crude ore nun& or quarried and 1.5 billion tons of mine waste and ore from development. This \vas an overall increase of 11% over that of 1992. These data do not include construction sand and gravel which until 1993 has been surveyed biennially. Starting in 1994, construction sand and gravel and the stones, which were also surveyed biennially, will be surveyed annually.

Jan 1, 1993

By K. Robert Dorman

This Bureau of Mines report describes laboratory and field experimentation in building mine ventilation stoppings, air-door frames, and fan bulkheads with a civil construction technique. Shotcrete is applied to a free-standing, three-dimensional wire-truss panel, which is easily cut and rapidly erected. In mines where shotcrete equipment is available, this technique should be faster and cheaper than conventional block-and-mortar or monolithic concrete construction.

Jan 1, 1980

By Stuart Lipoff, John E. Trombly, Paul Brien, O&apos

System objectives and design criteria for an in-mine ULF radio paging system are discussed. Coding formats, frequency and bandwidth selection criteria leading to the system design are discussed. The prototype call alert transmitter and pocket page receiver is functionally described. The report includes circuit descriptions, schematics, parts lists, printed circuit fabrication and assembly drawings. The report concludes with an estimate of the manufacturing cost for each assembly.

By D. E. Hirsch

The Bureau of Mines, as a part of American Petroleum Institute Research Project 60, Characterization of the Heavy Ends of Petroleum, has made extensive use of gel permeation chromatography (GPC). Data developed in this study were used to develop several correlations that greatly expanded the usefulness of GPC and the data have been used as an aid in the interpretation of mass spectra (MS). GPC retention volume data on pure compounds were used with molecular structure to develop correlations that can be used to accurately predict retention volumes, molecular volumes, densities, chain lengths, and ring numbers of many components of petroleum without resorting to further laboratory experimentation. Conversely, the correlation can be used to select or reject some compounds from several possible compounds that are indicated on the basis of MS analysis. The utility of these correlations in compound type characterization is demonstrated by showing their application to 330° to 550° C fractions from a low-sulfur and a high-sulfur crude oil.

Jan 1, 1974

By H. William Zeller

The Bureau of Mines performed laboratory research to determine the effects of a barium-based fuel additive on diesel particulate emissions. The test engine was typical of types used to power underground coal min-ing equipment. Test parameters consisted of baseline measurements without additive, three fuel additive concentrations, and five steady-state engine loads, all at 1,200 r/min. Additive effects on soot mass concen-tration, opacity, particle size distribution, volatile fraction, and NOx emissions were determined. Important findings are as follows: Using the manufacturer's recom-mended additive concentration increased the gravimetrically measured mass of particulate by 30 to 80 pct at four of the five steady-state load conditions. Soot measurements by optical methods did not agree with those by gravimetric techniques, for additive-treated fuels. The additive reduced volatile hydrocarbons adsorbed on filter deposits by up to 50 pet. At most engine loads, carbon particulate was also reduced. About 40 pet of the barium added to the fuel was accounted for in the exhaust. The health implications for miners were considered, but no firm conclusions were drawn or recommendations made because the results are for steady-state conditions, which may not be representative of real-world operation of diesel-powered equipment underground.

Jan 1, 1987

By J. K. Richmond

Early research on coal dust explosions by the Federal Bureau of Mines and in other countries is reviewed to examine the effect of a single inhibitor, rock dust, on the explosion limits of coal dust. The parameters studied in this research included coal dust fineness, volatile content, and type of initiation. This research resulted in appropriate safety regulations in the respective countries. Also reported are the results of recent research in the Experimental Mine of the Bureau of Mines to investigate in detail the limits of coal dust explosions; the research used three types of coal with rock dust added as the independent variable. New experimental techniques and new criteria for defining propagation/nonpropagation were applied to the experiments. Also, a limit explosion propagation model is proposed based on the assumption of rapid devolatilization of the coal particles, with the subsequent combustion of the evolved volatile products contributing primarily to the propagation of the explosions. The model assumes also that the resultant char acts mainly as an inert diluent similar to the rock dust. The model also suggests that the function of stronger initiation is mostly to lift more dust from the mine surfaces.

Jan 1, 1975

By Thomas M. Barczak, Christopher Mark

Roof supports can only be understood in conjunction with the rock structure that they support. The strength of the rock depends on geology, and the loads are applied primarily by the in situ and mining-induced stresses. Other factors, such as wider spans and retreat or multiple-seam mining, can also reduce the stability of mine openings. Roof supports are used to help stabilize these openings, but their performance characteristics must be properly matched to the loading environment and ground behavior if they are to succeed. Roof supports include both intrinsic supports, such as roof bolts, and standing supports. The key characteristics of any support include its maximum load-carrying capacity, stiffness, and residual strength. Other important factors are the timing of installation, the stability of the support as it is loaded, and the capability of the support system to provide skin control. This paper explains in practical terms how supports work and the important factors in ensuring that a good support design and application strategy are developed.

Jan 10, 2000

By Harvard Eng

An industrial survey was made for the Missouri Basin Field Committee of the Department of the Interior to determine the type and quantity of water-borne mineral wastes and the water requirements of metal-processing industries in the basin in Kansas and western Missouri. Data are presented on metal-processing plants visited through June 30, 1959. Most of the plants were in the greater Kansas City area. This report is to be supplemented with a similar publication on other industries, including those producing sand and gravel, coal, petroleum, and chemicals. In 1958, 19 million pounds of waste materials was discharged from metal processing industries. Approximately 14 million pounds of this waste was in the form of ferrous sulfate, and 2 million pounds was ferric phosphate. Galvanizing, other hot dipping, and automotive industries contributed the greater part of iron compounds wasted; some of this waste occurred as sludge that was not discharged to water courses but was hauled to refuse dumps, podium was present in nearly all industrial wastes, and the total of more than 900,000 pounds constituted one of the larger material losses. Although small in quantity, electroplating and allied coating wastes contained metals that were expensive when originally purchased.

Jan 1, 1961

By C. R. Stephan, N. B. Greninger, J. R. Lipscomb

The U.S. Bureau of Mines and the U.S. Mine Safety and Health Administration (MSHA) are participating jointly in a research program to evaluate the strength characteristics and air-leakage resistance of various proposed seal designs for use in underground coal mines. The full-scale seals were constructed in the USBM's experimental mine at the Lake Lynn Laboratory, air-leakage tested, then subjected to pressure pulses of 20 psig or greater. bjected to pressure pulses of 20 psig or greater. In experiments prior to this study, seven seal designs using solid-concrete blocks were tested. Only the standard-type seal passed the explosion and air-leakage criteria. Tests also were performed on four seals constructed with low-density foam blocks. All four of these seal designs withstood the pressure pulse. In more recent studies, nine cementitious foam seal designs of varying thicknesses and densities were investigated. Six of the nine designs successfully survived the explosion overpressures. Six wood- block convergence seals also have been tested. The typical 3-ft-thick, wood-block seal design currently used in many coal mines did not maintain its integrity, in the absence of convergence forces, following the explosion test. Five modified wood-block seals successfully withstood the 20-psig pressure pulse. Based on these tests, three alternative seal construction materials, cementitious foam, low-density foam block, and wood, have been approved by MSHA for use in underground coal mines.

Jan 1, 1993

In this Part, we have included copies of the flip charts and overhead projector viewgraphs used in the two briefings we conducted as part of this seismic detection and location task. The first one was an overview and problem definition briefing given to the seismic consultants on September 7, 1972. The second was a formal oral presentation of study results to technical staff members of the Pittsburgh Mining and Safety Research Center on November 21, 1972.

Jan 1, 1974