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The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment; including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that are recommended in this document, but all of the panic bars are characteristically of the ?fire door? type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they are required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in "Guidelines for the Design and Installation of Devices for Deenergization of Self -Propelled Electric Face Equipment/Automatic Emergency Brake s II by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel at the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By R. D. Van Zant

The method for smelting zinc in horizontal retorts developed several centuries ago is still in use. This process consists essentially of the reduction of zinc oxide by carbon at 1,200° to 1,400° C. in a fire-clay retort. The reaction is highly endothermic, and a high radiation loss occurs in transferring the heat of reaction through the fire-clay walls. In recent years, silicon carbide retorts with much better heat-transfer characteristics than fire clay have been supplanting the old retorts. The practical impossibility of recovering the carbon monoxide formed in the reduction causes a large loss of fuel. Intermittent smelting is done in small retorts that are manually charged and discharged, and the furnace crews must be specially trained if efficient results are to be obtained. During the past 20 years several processes have been introduced that have substantially improved the horizontal-retort process. One of these, developed by the New Jersey Zinc Co., consists of a continuous process in which a briquetted mixture of zinc sinter, reducing agent, and binder is coked at 750° to 900° C. and charged into a vertical silicon carbide retort. A supply of displacement air or exhaust combustion gas is introduced at the base of the retort at an appropriate pressure in order to keep the zinc vapor from condensing on the cooled residue in the lower part of the retort. Any .oxidizing constituents in the displacement gas are converted to carbon monoxide by reaction with the carbon in the charge. The spent residue is continuously removed at the bottom of tl1e retort. The chief advantages of this process are said to be increased output per man-day, improved working conditions, high recovery of zinc, increased thermal efficiency, and long retort life.

Jan 1, 1950

By E. C. Lane

This paper is the first part of a report giving the results of the Bureau of Mines' twenty-third semiannual survey of motor gasoline marketed in the United States. A companion report, Part II, is in preparation and will give a more detailed discussion of the whole survey. Results of the determination of copper-strip corrosion, color, sulphur content, copper-dish evaporation residue, and gum content as given by the Bureau of Mines steam-oven method will be presented in the second paper, which will also include the prevailing retail price and the tax at the time the sample was taken. This paper deals specifically with data relative to gravity, Reid vapor pressure,5 and distillation (method 100.13).6 The samples tested were divided into "competitive-price gasolines" and "premium-price motor fuels," a method of presentation that was begun with the twenty-second semiannual survey.7 A total of 312 samples were collected from service station pumps in 20 cities throughout the United States. Of this number of samples, 207 were "competitive-price gasolines" and 105 were "premium-price motor fuels." All of the samples were collected in March, 1931, and analyzed at the Petroleum Experiment Station of the United States Bureau of Miner at Bartlesville, Okla.

Jan 1, 1931

By Frank E. Cash, Roy G. Stott

This circular describes four modern change houses of the Lake Superior iron - ore district , all conceived and constructed since 1937. The oldest change house described herein was constructed and occupied in 1938 , yet it embodies the modern improvement of air - conditioning . The purpose of this report is to describe and illustrate improvements with regard to health and safety features combined in the construction , arrangement , ventilation , heating ,lighting , and other features , with the aid of photographs , sketches , and diagrams . The modern change house is a fire - resistant structure in which intermingling of men in mine clothes and men in street clothes , hazardous dust , heat and humidity , crowding , poor lighting , slippery and muddy floors , and inadequate facilities for clothes and for bathing have been largely eliminated . The miner coming off shift at a modern mine no longer faces the elements when he gets off the cage . He travels through a tunnel to the change house , where he is cooled gradually by room temperatures as he passes from the mineclothes section and shower room to the street - clothes room . He is assured of dry clothes when he is ready for them . No longer is he sent out of the change house into a muddy yard to drive away as best he can . The modern change house has an improved parking lot and graveled or concreted walkways from it to the change house entrances .

Jan 1, 1949

By P. B. Altringer

Searles Lake, CA, contains the largest known domestic tungsten resource. The brines in this near-dry lake bed, located in the Mojave Desert 130 mi northeast of Los Angeles, contain an estimated 135 MMlb of tungsten. However, the low concentration of tungsten (0.080 g/L W03) in the supersaturated brine makes selective tungsten extraction very difficult. Although many brine chemicals are extracted from the lake, tungsten recovery was an elusive goal prior to Bureau of Mines development of an ion-exchange technique. This publication describes the Bureau process. The following subjects are ad-dressed: ? The Searles Lake tungsten resource. ? General problems associated with tungsten recovery. ? Bureau research objectives. ? Synthesis of ion-exchange resins. ? Development of a two-stage ion-exchange tungsten extraction and concentration procedure. ? Product recovery and purification. ? Economic evaluation. Flowsheets for recovering three products (calcium tungstate, sodium tungstate, and tungstic oxide) are presented and evaluated, as well as a summary of the research effort and potential applications.

Jan 1, 1985

By D. S. Burgess

A commercially available Halon 1301 extinguisher has been evaluated as part of an explosion-suppression system for use in coal mines. Studies were made both of the dispersion pattern of the Halon 1301 at an initial pressure of 280 psig, and of the efficacy of this suppressant against 9.5 percent methane-air flames. These flames were quenched successfully only when the suppressant was applied before the fireball diameter exceeded 18 inches.

Jan 1, 1971

By Steven J. Schatzel

Prior research has suggested that the source of respirable silica dust in underground coal mines is typically the immediate top or bottom lithology adjacent to the mined seam, not mineral matter bound within the mined coal bed. Geochemical analyses were applied in an effort to identify the specific source rock of respirable quartz dust in coal mines. The analyses also demonstrate the compositional changes that take place in the generation of the respirable dust fraction from parent rock material. All six mine sites were mining coal with relatively low mineral matter content, although two mines were operating in the Fire Clay coal bed which contains a persistent tonstein. Interpretations of Ca, Mg, Mn, Na, and K concentrations strongly suggest that the top strata above the mined seam is the primary source of mineral dust produced during mining. One site indicates a mixed or bottom source, possibly due to site specific conditions. Respirable dust compositional analyses suggest a direct relationship between the quantity of mineral Si and the quantity of quartz Si. A similar relationship was not found in either the top or bottom rocks adjacent to the mined seam. An apparent loss of elemental Al was noted in the respirable dust fraction when compared to potential parent rock sources. Elemental Al is present in top and bottom rock strata within illite, kaolinite, feldspar, and chlorite. A possible explanation for loss of Al in the respirable dust samples is the removal of clays and possibly chlorite minerals. It is expected that removal of this portion of the Al bearing mineral matter occurs during rock abrasion and dust transport prior to dust capture on the samplers.

Jan 1, 2009

By John Nagy

The effect of low percentages of methane (0 to 5 pet.) in an air atmosphere on spark initiated explosions of coal dust was investigated. With low dust concentrations (0.1 to 0.4 oz./cu, ft.), small amounts of methane increase the explosion pressure; with larger dust concentrations (0.5 to 2.0 oz./cu. ft.), small amounts of methane decrease the explosion pressure. The rate of pressure rise of a coal dust explosion increases with increase in methane concentration; about 3 to 4 pct. further addition of methane yields a decrease in the rate of pressure rise. Convection currents created by the air or gas blast used to disperse dust produce an increase in explosion pressure and rate of pressure rise. The minimum explosive concentration of the coal dust decreases about linearly as the concentration of methane increases from 0 to 5 pct. The explosion pressure increases linearly as the initial pressure within the chamber increases. Similarities between coal dust and methane explosions are indicated, INTRODUCTION During coal mining, methane occluded in coal or adjoining strata is liberated into the mine atmosphere,4 Normally, the methane is diluted and swept away by the ventilating air. Under some conditions, through accidental disruption of the ventilation system, sudden outburst, or because insufficient fresh air is supplied to a working place, low percentages of methane may be present during mining operations. If it is permitted to accumulate, methane itself presents an explosion hazard; its limits of explosibility arc approximately 5 and 15 pct. The effect of low percentages of methane on the explosibility of coal dust was studied to provide a broader understanding of the hazards of ignition and explosion and thus to facilitate development of control

Jan 1, 1961

By M. D. Marshall

A survey showed that there were 24 bin-related fatalities in the 5 year period of 1975 to 1979 in the minerals industry. Only 4 victims wore safety belts and only 1 of these had a second person attending his lifeline, as mandated by Federal safety regulations. Not one victim observed the three main Federal safety regulations governing work in and around bins. A study was conducted on the force necessary to pull victims partially buried in sand and limestone. Recommendations are made on procedures and safety equipment that can minimize bin-related accidents. A Handbook, directed to the plant engineer responsible for bin design and safety, was also issued detailing bin designs and flow-aid accessories as a function of the flowability of the stored material to better maintain material flow from bins. A comprehensive table of the flowability of many materials produced in the minerals industry is presented and simple procedures given for determining the flowability of materials if not available.

Jan 1, 1984

By H. C. Ko

The Bureau of Mines maintains an active program in thermochemistry to provide thermodynamic data for the advancement of mineral science and technology. As part of this effort, the standard enthalpy of formation at 298.15 K, ?Hf°, for 2CdO-CdSO4 was determined by HCI acid solution calorimetry to be -345.69 ±0.61 kcal/mol.

Jan 1, 1983

By D. Harrington, W. J. Fene, H. B. Humphrey

In the fiscal years 1946 and 1947 the number of mine explosions decreased compared with the preceding years. However, the loss of life was so serious during the fiscal year 1947 the period when the Government administered bi- tuminous-coal and lignite mines that from April to June 1947 extraordinary measures were taken in mines then under Government possession to obtain com- pliance with provisions concerning rock dusting, ventilation, and blasting that had not been followed. The great loss of life in explosions during the fiscal year 1947 as compared with 1944, 1945, and 1946 is not easy to explain, but the necessity for maintaining adequate protection has been definitely demonstrated. Management, workers, and inspection agencies alike must keep the mines reasonably safe against explosions or allow them to lapse into a condition where chance is the principal protection against disaster. The at- tention given to protecting coal mines and the men employed in them against mine fires, following the disastrous fires in 1944 and 1945, has at least tem- porarily controlled this hazard loss of life from coal-mine fires was re- duced to 1 fatality in 1947. The number of fires was also less, and progress has been made in reducing the heavy losses in both life and property from un- derground coal-mine fires that occurred in the two years mentioned. Fatalities from mine explosions during the past 6 fiscal years, July 1942 to June 1947, totaled 674, and there were 149 explosions; during the preceding 6 years there were 655 fatalities in 132 explosions. The 6 fiscal years 1942- 47 cover the active period of Federal coal-mine inspection. During the fiscal year 1947, there were 154 fatalities from explosions compared with 58 during the fiscal year 1946, 64 in 1945, 94 in 1944, 152 in 1943, and 152 in 1942.

May 1, 1948

By W. W. Roepke

The linear cutting system, developed by the U.S. Bureau of Mines, uses geometric principles developed by Cardan to produce a nearly constant cut depth. The new system has been extensively tested in a synthetic material under laboratory conditions to verify mechanical capability and to identify operational characteristics. Comparisons between 15-rpm linear cutting and 50-rpm rotary cutting systems show significant improvement in respirable dust entrainment, product size distribution, and energy usage. Respirable dust is reduced by as much as 90 pct. Recovered product showed a 67-pct reduction in -0.32-cm (-1/8-in) material and a 200-pct increase in +5.08 cm (+2 in) material. Average power was reduced by 66 pct for the linear cutting. Because the bit cutting paths differ between linear and rotary cutting, it was necessary to compare the two at the same cut depths and bit types. These comparisons show that low revolution per minute rotary cutting entrains about the same amount of respirable dust as the linear cutting system, but the average shaft torque may be 55 to 130 pct greater for the rotary system.

Jan 1, 2010

By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1954 was made under a co-operative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 101 samples of aviation gasoline. Data also are given for 30 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers I 1954 production in their laboratories and the results submitted to the Bureau of Mines for compilation. The products of 19 manufacturers of aviation gasolines and of 15 producers of aviation jet fuels are represented.

Jan 1, 1955

By Launa G. Mallett, Charles Vaught, Dana C. Reinke, Lisa J. Steiner, Lynn L. Rethi, Kathleen M. Kowalski-Trakofler, Jr. Brnich, William J. Wiehagen

Safety and health professionals recognize that training is a critical element of any effective safety and health program. An extensive literature survey has led the authors to conclude that we are at the beginning of a revolution in training due to changes in the demographics of the workforce, the rapid growth of technology, and the universal ascendance of the information age. Of present major concern in the mining industry is how to provide appropriate training for an aging workforce and concurrently develop training for the expected influx of new and less experienced miners as older workers retire. This report explores the key issues in the changing safety and health training area as identified by the multidisciplinary team of NIOSH researchers who conducted the literature survey. Issues include generational differences between newer mine workers and the present workforce with respect to their physical, psychological, social, and cultural characteristics; their learning styles and work expectations; and the impact of technology. Some preliminary conclusions are offered for future training needs.

Jul 1, 2004

By Margaret R. Egan

This Bureau of Mines report presents results from experimental studies on wood crib fires in an intermediate-scale fire tunnel. Gas concentrations, smoke particle characteristics, heat release rates, and ventilation rates were determined. These measurements form a data base for wood, which can be used with previous analyses for coal and future studies of other mine combustibles, to comprehend the potential hazards of these materials in underground mine fires. A knowledge of the combustion products emitted from these materials will benefit fire detection and control. Results show the changes in burning rate and heat release rate produced by different crib configurations and ventilation rates. Also included are the effects that the burning rate has on smoke characteristics and gas production.

Jan 1, 1986

By Alan G. Mayton

The Bureau of Mines conducted one of the most extensive studies on surface mine illumination to date, to assess the illumination needs of mobile surface mining machinery with respect to the visual tasks required of machinery operators. Field Investigations were performed at 22 surface mining operations, coal and metal-nonmetal, within several mining regions of the United States. Visibility and illumination were measured for 159 visual tasks performed by equipment operators on or near 57 surface mining machines, including draglines, shovels, blasthole drills, bulldozers, loaders, haul trucks, graders, scrapers, and several service-type vehicles.

Jan 1, 1987

By J. M. Mutmansky, C. Lee

"Measurement of the size and elemental characteristics was performed on airborne coal mine dust samples collected by multi-stage cascade impactors as well as channel samples of the geologic materials. Size distributions were obtained using precise weighing techniques on the impactor substrates. Elemental analysis on the samples was performed by the proton-induced x-ray emission (PIXE) method, a rapid and non-destructive method of multi-element analysis.The various analyses were performed on 9 major and 21 trace elements. The results indicate the importance of intake air and shuttle car movements as sources of dust. The association of coal dust characteristics with channel samples was investigated using the coefficient of proportional similarity as a statistical measure. Results show a strong relationship between major elements and the geologic material being cut but a similar relationship between trace elements and geologic materials is not consistent.1. INTRODUCTIONThe most significant occupational disease in the coal industry is known ·as coal workers' pneumoconiosis (CW'P). While CW'P has existed for centuries, its mechanism of occurrence and association with coal dust has been well understood for only a few decades. In the 1930s, the significance of this disease led state and government officials in the USA to perform extensive epidemiological and environmental studies in the major coalfields. Study of these results plus later studies in the coal producing countries of Europe eventually led to the dust regulations that appear in the Federal Coal Mine Health and Safety Act of 1969.The impacts of the 1969 act were a productivity decline and increased production cost. Many analysts attributed this in large part to difficulties in complying with the new dust standards (Brezovic 1981). However, compliance was met in most continuous miner sections rather quickly. The remaining problem area is that of longwall mining where the procedures and layout of the minin~ system make it difficult to meet the standards."

Jan 1, 1989

By Gregory J. Chekan

The Bureau of Mines, in an effort to improve planning and development in coal mining, is investigating strata interactions associated with mining of multiple coalbeds. Two common interactions that occur between adjacent coalbeds are subsidence and pillar load transfer. The study described involves underground observations and measurements conducted at two Pennsylvania mines, each affected by one of these interactions. At the mine affected by subsidence, measurements show that undermining had little effect on upper mine pillar stability, but had a more severe effect on the development and maintenance of entries. Roof-to-floor measurements recorded over four times more convergence in entries developed over gob as compared with entries developed over support pillars in the lower mine. At the mine affected by pillar load transfer, Initial in situ measurements have shown the existence of a pressure arch in the lower workings. Prior research has shown that arch interaction between two adjacent openings can create stress concentrations in the in-nerburden. Underground measurements and results obtained from both mine sites correlate with theoretical and photoelastic multiple-seam models, and eventually these field data will serve to refine model accuracy. Further study of multiple-seam interaction mechanisms will lead to improved mine planning, increased resource conservation, and a safer working environment.

Jan 1, 1986

By G. W. Birge, D. E. Wolfson, J. H. Lynch

Fourteen coal samples representing the Flag , Fire Clay , Whitesburg , Amburgy , Upper Elkhorn No. 3 , Upper Elkhorn No. 2 , Upper Elkhorn No. 1 , and Lower Elkhorn beds in Letcher County , Ky . , were carbonized by the Bureau of Mines - American Gas Association ( BM- AGA ) method , and yields of products and physical properties of cokes were determined . The samples tested were high- volatile A bituminous in rank , with dry , mineral - matter- free fixed - carbon contents ranging from 55.3 to 62.2 percent . Five of the samples , as received , were chemically unsuitable for metallurgical use because of excessive ash and/ or sulfur content . Generally , strength indexes of the cokes were low and all of the coals would require blending with higher rank coal to obtain satisfactory blast furnace fuel .

Jan 1, 1964

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag compositions. The present report deals with the SrF2-Y2O3 system for which liquidus and solidus temperatures and solid solubilities were determined. The information is presented as the phase diagram. The phase diagram was constructed from information obtained by ceramogra¬phy, X-ray diffraction, thermal analysis, and electron probe microanalysis of small specimens encapsulated in platinum-20 percent rhodium or molybdenum ampoules. The data indicate a simple eutectic system with limited terminal solid solubilities. The eutectic temperature is 1,457°±5° C, and the eutectic composition is 4±1 mole-pct Y203. Strontium fluoride containing up to 2 wt-pct 0 2 was studied to determine the effects of oxygen contamination. Oxygen levels in excess of 0.2 wt-pct resulted in eutectic formation between SrF2 and SrO. The eutectic composition is between 0.2 and 0.7 wt-pct 02, and the eutectic temperature is 1,447°±5° C. No intermediate oxyfluoride phases were detected.

Jan 1, 1974