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Research workers from the Bureau of Mines and industry met with other government and industry representatives at the Mont Chateau Lodge, Morgantown, W. Va., on May 30-31, 1973, to discuss the current status of methane control in eastern U.S. coal mines. The opening remarks, the eight technical presentations, and the discussions of the members of a government-industry panel are published here for the benefit of those concerned with the control of methane in coal mines. In addition, an introduction has been added to present the background of work in this field.

Jan 1, 1973

By Elizabeth A. Johnson

The effect of slag composition on lead losses to slags and on the behavior of associated accessory elements in lead blast furnace smelting has been studied by the Bureau of Mines. Equilibrations of 30 g of lead and synthetic slag doped with Cu, In, TI, and Sb at 1,200° C in CO-C02 atmospheres revealed the importance of the FeO:Si02 ratio and the basicity ratio, (CaO+MgO):SiO2, of the slag. Lead losses to slags increased with an increasing FeO:Si02 ratio and decreased with an in-creasing basicity ratio. Copper and indium distribution coefficients, [Lx =] increased from 15 at the lower basicity ratios to near 60 at higher basicity ratios. LTI values increased from 20 to 150 as slag basicity increased. Lcu, Lin, and LTI were relatively in-dependent of the FeO:Si02 ratio, but increased with greater amounts of accessory elements in the system. Antimony distribution alone was shown to be strongly affected by FeO:Si02 ratio, although data were scattered. LSb values ranged from 20 to 800 and decreased sharply with increasing FeO:Si02 ratios. The basicity ratio and the level of accessory element load did not have any noticeable effect on LSb.

Jan 1, 1983

By d&apos, Kathleen J. Amico

THIS SUMMARY is shown in volumes I and III of this series on mineral production in the United States (including Alaska and Hawaii), its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, and on the principal minerals imported into and exported from the United States. For further details on production, see the several commodity and area chapters. A summary table comparing world and U.S. mineral production also is included. [ ]

Jan 1, 1960

By V. R. Miller

The Bureau of Mines has developed a technique to separate and recover the three major components, Pb, Zn, and Cd, from lead smelter flue dust. This research was conducted as part of the Bureau's effort to reduce environmental conflicts and occupational hazards associated with mineral-processing operations and to recover valuable constituents in emissions and effluents. The laboratory process utilizes sulfation roasting of the flue dust followed by water leaching to extract over 95 pct of the cadmium and zinc. Ninety-nine percent of the cadmium was recovered from solution by cementing with zinc dust, and zinc was electrowon from the resulting solution after purification. Zinc electrolysis was carried out in a 1-liter cell at 35° C with a cathode-current density of 8 A/dm2 in a solution containing 65 g/l Zn++ and 180 g/l H2S04, Current efficiencies of 80 pct were obtained. The leached residue consisted largely of PbS04, which was converted to PbC03 and leached with H2SiF6 to produce PbSiF6 electrolyte. Ninety-five percent of the lead contained in the residue was converted to electrolyte. Lead was electrowon from solutions containing 70 gil Pb++ and 90 g/l H2SiF6 using a lead cathode, Pb02-coated titanium anodes at 28° C, and a current density of 1.6 A/dm2. Current efficiencies approaching 92 pct were obtained. Accessory minerals such as cobalt and nickel were separated into purification residues and liquor.

Jan 1, 1982

By A. T. Iannacchione, D. G. Puglio

This Bureau of Mines study covers 25 underground mines that were active in the Upper and Lower Freeport and Lower Kittanning coalbeds in 1976. The coal ranges from low to medium volatile in rank; its primary use is for steam generation. Seven mines emit more than 100,000 cfd of methane gas; those mines are the deepest and largest producers. The methane gas content of three core samples of the Lower Kittanning coalbed was estimated by the direct method. A sample from a depth of 320 feet contained 0.5 cu cm of gas per gram, at 620 feet there was 0.8 cu cm of gas per gram, and at 1,060 feet there was 11 cu cm of gas per gram. These results suggest that methane control problems will be encountered in the future as deeper coal is mined.

Jan 1, 1979

Water infiltration control techniques are designed to reduce the total volume of water entering an underground mine, and thus, reduce the volume of mine water discharge During the development of underground mines, water may be encountered in various quantities This water must be pumped from the mine during active mining, and in many situations, the weight of water removed will be more than the total weight of mineral extracted After abandonment of the mine, infiltrating water either floods the mine workings or discharges from the mine (27, 127) Infiltrating water may enter underground mines from above, below, or laterally through adjacent rock strata Earth fractures such as faults, joints, and roof fractures resulting from surface subsidence are commonly primary causes of water entrance Into abandoned underground mines Factors affecting the quantity of water entering a mine will be the depth of the mine, location of water bearing strata, and ground water flow patterns Investigations of the quantity of water entering underground coal mines have found the average rate of infiltration to range from approximately 6,262 to 10,280 liters per hectare per day (670 to 1,100 gal/acre/day) (27) Water flowing through underground mines flushes pollutants from the mine and may result in their discharge to the environment A reduction in the amount of flow usually results in a reduction in total pollution load discharging from the mine The techniques discussed in this section can be used to reduce the volume of surface and groundwater available to enter the mine system and transport pollutants The selection of a control technique will depend upon the characteristics of the mine system and the expected cost effectiveness of the technique In order for water infiltration control to be effective in controlling mine drainage pollution, the reduction in mine water flow must not be accompanied by an increase in concentration of pollutants (127) REFERENCES 2, 27, 51, 58, 127, 132

Jan 1, 1975

By Jeffery M. Listak, Ernest A. Curth

"It took only 9 years from the first appearance of roof shields on the U.S. longwall mining scene to the present predominance of shield faces. An apparent consequence is the welcome downward trend in accidents related to failures in longwall ground control. The report addresses load prediction, the effects of shield geometry on support loads, factors contributing to ground control, and related techniques. The Bureau of Mines took an active part in the evolution of longwall mining, including developing one of the first shield faces in 1975, the first lemniscatetype shields in 1976, the Mine Roof Simulator completed in 1980, the first shields in steeply pitching coalbeds in 1981, and the first multilift working of a thick coalbed in 1982. The information offered in this state-of-the-art report will assist in establishing criteria for roof support selection. INTRODUCTIONIn terms of roof support technology, the introduction of shields in the seventies and eighties was a major step forward. Table 1 indicates the predominance of shield faces on the U.S. longwall mining scene and its apparent consequence, a welcome downward trend of ground-control related accidents.The rapid progress of longwall technology began in 1975 and is highlighted by a development leading from the caliper shield to the modern lemniscate type. Shields have been gaining preference over chocks since their advent to longwall mining in 1975. Safety and productivity factors favoring shields over chocks are--1. A sheltered working space requiring minimum cleanup work.2. Structural stability that allows advancing without delay even with brushing roof contact and, by controlling all lateral loads, removing the requirement for cumbersome leg restraint and restoration devices.3. Wide hydraulic range of mining height.The development of roof shields in the Federal Republic of Germany preceded and paralleled their rapid adoption by U.S. miners. In 1983, 87 pct of the total production in Germany came from shield faces (1).2 In Great Britain, the National Coal Board introduced the first shield support system in 1977 to initiate Advanced Mining Technology (ATM) and Heavy Duty Mechanization (HDM) programs; as of mid-1982, 44 shield faces were operating, or 7.5 pct of a total of 581 faces CJ_)."

Jan 1, 1985

By M. M. Fine

A satisfactory mean: of beneficiating a Brazilian phosphate rock was developed in a mineral-dressing-research study by the Bureau of Mines. High-grade concentrates well ever the specified minimum grade of 70 percent tricalcium phosphate, were produced, with goad recoveries by agglomerate tabling and flotation. A lower gads but usable secondary product was recovered by sedimentation of the minus-200-mesh fraction of the ore. The ore wan representative of an extensive deposit recently discovered near Recife in the State of Pernambuco, Brazil, which will be exploited in a plant planned to eventually produce at the rate of 500,000 tons of concentrate annually. Although Brazil has been reported to Lave a substantial reserve of phosphate rock,3/ the country has never been more than a small producer of this commodity. From 1945 to 1950 the highest production of phosphate rock attained in Brazil amounted to 10,421 tons. Production in 1949, the most recent year for which figures are available, was 4,553 tons.4/

Jan 1, 1954

By Christopher C. Jobes, Alan G. Mayton, Farid Amirouche

Based on prior mine vehicle studies of operators’ exposure to whole-body vibration, researchers from the National Institute for Occupational Safety and Health (NIOSH) evaluated four seat designs on mine haulage vehicles, with regard to roadway-induced jarring/jolting and operator comfort. Investigators collected objective and subjective data from vehicle operators on two existing and two NIOSH seat designs. This study included time and frequency response data using accelerometers and a data recorder, operator perceptions of jarring/jolting and discomfort levels using a linear visual analogue scale, and data from a questionnaire developed for this study. Results from the analysis of subjective data show that operators generally favoured the NIOSH-designed seats over the existing seats. The results of analyses from the absorbed power method and the threshold limit method, based on ISO 2631-1 (ISO, 1985), support the premise that NIOSH seat designs are superior to the existing vehicle seat designs on both models of mine shuttle cars used in the study. The NIOSH seat designs, featuring viscoelastic foam padding, were more effective in reducing vibration energy for operators exposed to vehicle jarring/jolting. In this paper, the performances of the NIOSH and existing seat designs are compared relative to the operator’s exposure to vehicle vibration (mainly jarring/jolting).

By F. P. Haver

The Bureau of Mines developed a process to extract about 90 percent of the sulfur from molybdenite flotation concentrate by compacting the concentrate with one-quarter of its weight of aluminum powder, heating it at 800° C for 30 minutes, and then allowing the product to react with water. This thermite reduction yields an impure molybdenum alloy plus aluminum sulfide. The latter readily hydrolyzes, to yield pure hydrogen sulfide which can be converted to elemental sulfur by the Claus process. At least 95 percent of the molybdenum can be subsequently recovered as 99.95-percent-pure molybdic oxide.

Jan 1, 1968

By Richard J. Kline

This publication comprises tables listing friction loss for a flexible, spiral-reinforced circular ventilation tubing system. The tables were constructed with the following parameters: a friction factor of 62 X 10-10, 10-foot sections of tubing ranging in total length from 100 to 550 feet, air quantities ranging from 1,000 to 15,000 cfm, and one to four 90° bends in the tubing. The aim of this publication is to improve ventilation tubing analysis and to provide a method of proper fan selection.

Jan 1, 1971

By Paul C. Turner

The U.S. Bureau of Mines, through an Interagency Agreement with the U.S. Army Tank-Automotive Command (TACOM), has successfully developed a steel expendable pattern casting process (EPC) for the manufacture of armorplate. The new armor is lighter and more ballistically effective than conventional rolled homogeneous armor (RHA), and costs less. An applique armor spinoff from the program was field-tested during the Gulf War. The applique armor withstood direct impacts from enemy munitions without failure.

Jan 1, 2010

By John M. Devine

The oxygen bomb-is used extensively for determining sulphur in petroleum, although it has been suspected that the results obtained with this method are somewhat lower than the true varies. In this paper are compared the results given by the oxygen-bomb and Carius methods, the latter being generally accepted as the standard procedure for the determination of sulphur in organic compounds. The Carius determinations given hero were made in connection with a special study of this method.4 Only petroleum oils of the less-volatile type are covered in the present work. Summary and Conclusions. When used with oils containing 2.3 to 0.15 per cent of sulphur the oxygen-bomb method gives results that are consistenly if slightly lower than those obtained with the Carius method. This variation, for the oils used, amounts to 3.1 per cent (on tae basis of sulphur present) for the sample containing 2.47 per cent of sulphur, and gradually increases (as the percentage of sulphur in the oils decreases) to 7.3 per cent for the oil containing 0.15 per cent of sulphur. With the oils studied the presence of ammonium nitrate in the bomb does not influence the results materially.

Jan 1, 1928

By Hal H. Engel

This publication was written in response to numerous requests for information about the Federal Bureau of Mines' "Demonstrated Lecture on Flame Propagation and Permissible and Explosion-Proof Electrical Equipment." The requests came principally from: (1) Persons wanting to know more about the demonstration before requesting it for groups they represented; (2) persons wishing advance information to help publicize a meeting where the demonstration was to be given; and (3) members of audiences desiring something to help them remember the salient points, facts, and figures presented during the lecture and demonstration. The purpose of the demonstration that accompanies the lecture is to show: (1) Variations in flame speed and pressure at various percentages of flammable gas within the flammable range; (2) effect of flame speed on the "pressure piling" within the area confining the mixture; and (3) the application of flame speed and pressure piling to the combustion of surrounding gas and to the design and maintenance of electrical equipment used in hazardous locations.

Jan 1, 1960

This chapter describes the adverse health effects associated with exposure to respirable coal mine dust. Epidemiological studies of underground and surface coal miners in the United States and other countries are discussed. Also discussed are animal studies that add to our understanding of particle deposition and retention in the lungs and associated disease responses. This chapter emphasizes studies that (1) were performed since the passage of the Federal Coal Mine Health and Safety Act of 1969 [P.L. 91- 173], (2) used standardized methods of exposure monitoring and disease classification, and (3) investigated exposure-response relationships between respirable coal mine dust exposure and disease. Several published review articles contain further discussion of health effects studies of coal miners [Attfield and Wagner 1992b; Petsonk and Attfield 1994; Cotes and Steel 1987; Merchant et al. 1986; Morgan and Lapp 1976; Morgan 1975].

Jan 1, 1997

By Joseph E. Matta

The Bureau of Mines conducted tests using a tracer-gas technique to measure the effectiveness of the jet fan, which is often employed in mines to ventilate dead headings. Results of these tests show that jet fans can (1) ventilate dead headings beyond the maximum penetration distance indicated by smoke-tube detection of air movement, and (2) redistribute available fresh air through larger working areas. However, if the fresh air base is insufficient, the fan will merely recirculate the contaminated air and disperse it over a larger volume.

Jan 1, 1978

By Paul Sands

Single- and two-stage tests were made with 6-inch, coal-cleaning hydrocyclones to determine the effect of hydrocyclone geometry, operating conditions, and feed composition on performance. Most of the testing was conducted in an open-circuit pilot plant that had a maximum capacity of about 9 tons per hour. The coals used in the investigation had top sizes of 1/4 inch and 28 mesh. Considerable latitude was found in the range of geometry variables that could be used without affecting performance adversely, although a certain minimum ratio of overflow to underflow openings had to be maintained for best operation. Two-stage cleaning proved distinctly better than operation with a single hydrocyclone, because clean coal lost in the refuse product of the primary unit can be partly recovered in the secondary. There is an unusually great difference in the specific gravities at which the individual sizes of the feed are separated in the hydrocyclone. This militates against high efficiency because maximum yield occurs when all sizes are cleaned at the same specific gravity. The size composition of the feed and, more particularly, the size composition of the impurity have a greater influence on the efficiency attainable in the hydrocyclone than in most other types of fine-coal cleaners.

Jan 1, 1968

By W. A. Haley

The purpose of this investigation was to develop and improve mining methods for mining thin coal beds, to increase productivity, and to increase the recovery of coal. German coal planers and a modified longwall system of mining were introduced into American mines and are bringing about increased productivity and better recovery as compared with the conventional methods displaced. Since the first installation, 4 additional planers have been purchased by coal companies and over 1-1/2 mil¬lion tons of coal has been mined by them, using the modified longwall mining method. INTRODUCTION Except from 1932 to 1934, the growth of mechanical loading in underground bituminous-coal and lignite mines in the United States has increased steadily. The amount of coal loaded mechanically in underground mines has increased from 0.3 percent in 1923 to 79.6 percent of the total underground production in 1953.3/ The use of new and improved mining machines and auxiliary equipment, together with new techniques in mining methods, usually has resulted in increased productivity.

Jan 1, 1957

By A. V. Hooker, E. J. Coggeshall

"The Bureau of Mines for some time advocated the firing of all blasts in coal mines as single shots, and this method of firing is the general practice in American bituminous-coal mines. All single shots can be fired with permissible single-shot units so designed that they will not ignite mixtures of methane and air.If several shots in a face are fired singly it is necessary to return the face after each shot. In some mines having steeply pitching coal seams, this may be dangerous or even impossible, under these conditions shots are usually fired simultaneously.Several shots cannot be fixed simultaneously with permissible single-shot blasting units, and safe types of multiple shots blasters are not readily available. This means that the firing of multiple shots in gassy mines is usually accompanied by the possibility of gas ignition as the blast occurs.Tests have been made at the Pittsburgh Experiment Station to determine the possibility of developing safe types of multiple-shot units suitable for such use, or of applying other type safely in gassy sections of mines where firing shots singly is impracticable.The tests may be divided into the following four groups:1. Tests to demonstrate hazard in the use of existing types of multiple-shot units of the portable generator type.2. Tests to show the electrical characteristics of multiple-shot generator units relative to the possibility of preventing igniting sparks and of modifying the design and application of such units in furthering safety."

Mar 1, 1935

By W. D. Bensema, J. W. Adams, W. W. Scott, H. Dobroski

Measurements of the absolute value of electromagnetic noise and attenuation along a hoist rope were made in an operating hard-rock mine, Lucky Friday Mine, located near Wallace, Idaho. Spectra of electromagnetic noise generated by various pieces of equipment, spectra of specific noise signals at various depths, and noise and attenuation on the 4250 foot (1295 meter) hoist, were measured. Three techniques were used to make the measurements. First, noise was measured over the en- tire electromagnetic spectrum of interest for brief time periods. Data were recorded using broadband analog magnetic tape for later transformation to spectral plots. Second, noise amplitudes were recorded at several discrete frequencies for a sufficient amount of time to provide data for amplitude probability distributions. A third technique gave attenuation data through the direct measurement of field strength at various depths. The specific measured results are given in a number of spectral plots, amplitude probability distribution plots and amplitude curves as a function of depth.

Jan 10, 1974