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By D. E. Hirsch

The Bureau of Mines has developed a systematic procedure for separation, characterization, and semiquantitative analysis of high-boiling (350° to 550° C) distillates of crude oils. Isothermal and molecular distillation were used to prepare the 370° to 530° C distillate of Recluse, Wyo., crude oil. The distillate was separated into fractions by chemical treatment, silica-alumina gel adsorption, and gel permeation chromatography (GPC). The fractions were analyzed by use of GPC correlations and mass and nuclear magnetic resonance (NMR) spectrometry. The increased knowledge of petroleum composition obtained from the data will contribute to improved petroleum processing and utilization and energy conservation.

Jan 1, 1974

By B. Dimitriades

Data on smog-forming reactivities of exhaust aldehydes are scarce. Such data were obtained by irradiating in a smog chamber typical exhaust aldehydes, individually and in exhaustlike mixtures. Observed reactivity manifestations were rate of nitrogen dioxide formation (RNO2) and yields of oxidant, peroxyacetyl nitrate, and formaldehyde. Results showed that exhaust aldehydes vary widely in reactivity. Formaldehyde showed high RNO2 reactivity but low oxidant yield; benzaldehyde, [m]-, and [p]-tolualdehyde were totally unreactive when irradiated individually; [o]-tolualdehyde was reactive. In mixtures, benzaldehyde manifested reactivity in terms of peroxybenzoyl nitrate yield. Exhaust aldehydes as a group are judged to be as reactive as the exhaust olefin group. The importance of the aldehyde contribution to exhaust reactivity and methods for assessing such contribution are discussed.

Jan 1, 1971

By John J. Sammarco

Mining has one of the highest annual average fatality rates among major US industries. Health and safety dangers have been inherent to mining since the early days of picks and shovels. Even though miners' health and safety has improved over the years, mining is still one of the most dangerous occupations. Mining was traditionally a low tech industry. It is now driven by competitive pressures to go high-tech by using programmable electronics (PE) for machine control, atmospheric monitoring and material processing. The industry's experience with the functional safety of PE is limited compared with other industries. Thus, PE is an emerging technology for mining that can potentially create or worsen hazards. The US National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory in Pittsburgh, PA is addressing the safety of this new technology. NIOSH has a proactive project to generate recommendations for addressing the functional safety of PE-based mining systems before the technology proliferates. The recommendations take the form of a safety framework encompassing the entire life cycle for a PE-based mining system.

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 Susan M. Moore

Many challenges are faced by workers in lower-seam (42 inches or less) mines. The lower-seam heights confine mine workers to their knees as they perform their daily tasks such as installing roof bolts, delivering supplies, repairing belt, or cutting coal. Miners working in these lower seams often consider kneepads to be their only line of defense against knee injuries. However, healthy knees do not start and stop with kneepads. Other interventions such as changing postures, proper hygiene, and work station design may also be used to reduce mine workers? risks for developing knee injuries. Incorporating these and many other interventions into a mine worker?s ?way of life? is an important step to ensuring a long, healthy career and retirement. Keeping knees healthy is also a key aspect to reducing costs in low-seam mines as the industry battles rising health care costs, and training/recruitment of replacement workers is time-consuming and costly. Educating the workforce about the possible interventions to reduce knee injury risk is a primary objective for the National Institute for Occupational Safety and Health?s (NIOSH) Pittsburgh Research Laboratory (PRL). Therefore, NIOSH researchers, along with industry and academia, developed a training package to educate the mining com­munity about some possible interventions beyond kneepads that may be used to help decrease knee injury rates. Increased awareness and simple changes are the first steps to reducing knee injuries.

Jan 1, 2008

By V. C. Petersen

The titanium-rich end of the titanium-germanium system was investigated by x-ray and metallographic methods and verified by resistivity and dilatometer measurements. A constitution diagram is proposed. The titanium-rich portion of the phase diagram is characterized by eutectic and peritectic reactions. The eutectic composition is 19 percent germanium, and the eutectic temperature 1,360° C. The peritectic reaction occurs at 905° C. and 4 percent germanium. Germanium is soluble in alpha titanium to a maximum of 4 percent at 905° C. and in beta titanium to a maximum of 12.5 percent at 1,360° C. Both limits of solubility decrease with decreasing temperatures. Although substantial quantities of germanium are soluble in beta titanium, beta is not retained on quenching. The beta phase probably transforms to alpha by a martensitic reaction.

Jan 1, 1957

By F. J. Gallagher

Some serious fires have occurred in bituminous-coal mines because of short circuits on direct-current power systems that do not have adequate circuit-breaker protection. The writer's observation of circuit-breaker installations in numerous coal mines leads to the conclusion that many persons am not properly informed as to the true functions, limitations, and operation of circuit breakers. Faulty protection results in fire hazards that endanger lives and property. Proper circuit-breaker protection would greatly minimize or, in many instances, eliminate the hazards; moreover, many operating advantages of proper application of modern circuit breakers would be gained. The purpose of this circular is to show why fire hazards exist in many mines despite the use of circuit breakers and how, the hazards may be overcome. A method is given for determining whether additional circuit-breaker, protection is required for a specific 250/275-volt direct-current distribution system, and, if so, the approximate locations and capacities of the required supplemental breakers.

Jan 1, 1951

By R. J. Matetic

Researchers associated with the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory (PRL), are investigating injuries (fatal and nonfatal) attributed to water well drillers during well drilling activities. Injury data, obtained from various sources, suggest that many water well drillers are experiencing unnecessarily high insurance premiums and very avoidable citations or violations from the direct result of accidents, injuries, and fatalities occurring throughout the water well drilling industry. Expensive insurance premiums and unnecessary citations are the direct result of poor health and safety practices. Visits to numerous water well drilling sites were conducted by NIOSH personnel to characterize and identify the injury data collected and to provide inexpensive strategies to prevent, minimize, and eliminate safety and health issues associated with water well drilling activities.

Jan 1, 2001

By W. H. Frederic, A. C. Fieldner, W. A. Selvig

"Low-rank coals have a pronounced tendency to disintegrate or ""slack” when alternately dried, and wetted by exposure to the weather. The more readily a coal slacks the greater is its tendency to ignite spontaneously and the more care must be used in its shipment and storage. Lignite slacks very readily when exposed to the weather. Slacking trouble is also experienced in shipping and storing subbituminous coal, but not to the same extent as with lignite. As a rule, bituminous coals are only slightly affected by weathering and in general may be classified as nonslacking coals. The slacking tendency of subbituminous coal is one of the characteristics that is used to distinguish it from bituminous coal. An accelerated laboratory method of test was developed to measure such slacking tendencies. This method was applied to a number of coals, principally from the State of Washington, and the method and the results obtained are given herein.Helpful information concerning slacking tendencies of coal was received from Marius R. Campbell, senior geologist U. S. Geological Survey.Coals that slack readily contain relatively large amounts of moisture. When exposed to the weather such coals lore moisture rapidly. As the coal loses moisture at the surface there is a gradual drift of moisture from the interior of the piece to the surface. If the loss of moisture at the surface proceeds at a faster rate than it is replaced by moisture from the interior of the coal piece, there undoubtedly in greater shrinkage of the coal at the surface as tom-pared to the interior of the piece and stressed are generated in the surface coal.These stresses in the surface coal cause it to crack and disintegrate.Likewise, when the air-dried coal is wetted by rain, the exposed surface of the coal pieces gain moisture more rapidly than the interior of the piece, causing greater expansion in the surface coal and the coal breaks down further. As this process of air drying and wetting is continued when the coal is exposed to the weather, the slacking proceeds and the exposed lumps of coal may disintegrate completely."

Nov 1, 1930

By F. S. Crawford

Companies which have been engaged in safety work for a number of years are becoming increasingly aware of the fact that it is not enough to supply guards for various pieces of machinery and equipment and to supply safety inspection to see that rules are being carried out. Studies of many safety organizations have demonstrated that the accidents which could have been prevented by proper guards constitute only a small percentage of the total acci- dents, and amount to perhaps not more than 15 per cent. Evidently, if success is to be attained in preventing all accidents which it is humanly possible to prevent, a company must have the cooperation of every employee. Mining particularly presents probably the greatest hazards of any industry. Prevention of accidents. is made increasingly difficult because men often work alone, although generally in pairs, and only in the concentrated systems of mining do they usually work in groups of more than three or four. Supervision is difficult, therefore, and much reliance must be placed upon the individual workmen. In mining, as perhaps in no other occupation, it is of the greatest importance that individual workmen should receive continuous safety education. Within the last few years safety education has come to the front as one of the most important of accident-prevention measures, although it is true that its importance has been repeatedly stressed by the United States Bureau of Mines and other national safety organizations since the inception of the safety movement many years ago. A review of the safety educational methods of some companies in the Lake Superior district should be of interest. Perhaps better methods are in use in other parts of the country, but the methods shown have been instrumental in many cases in reducing the number of accidents. In one mine in the district whose methods are described the frequency of accidents has been reduced to zero within the last two years. A number of other mines in the district have recently gone into the class having no lost-time accidents for considerable periods of time. One company in the Lake Superior region, operating over 30 mines, succeeded during one month of 1930 in operating every mine without having a single accident which caused lost time beyond the day of the injury. Records like these are increasing in number, and while it is believed that they are the combined result of different means of safety activity, it is undoubtedly true that many of these results were obtained through safety educational methods.

Sep 1, 1931

By J. F. Messerly

The purity of three specially prepared samples of benzene was determined with an adiabatic, low-temperature calorimeter with automatic control of shield temperature. Extensive measurements were made on each sample to determine how variations in operating procedures affect melting-point and freezing-point as well as purity data obtained by the calorimetric method. Detailed results of the investigations are presented, and effects of different operating procedures are discussed, together with problems encountered in interpretating experimental results.

Jan 1, 1963

By Francis X. Cannaday

The Bureau of Mines developed equipment to measure the sonic velocity of pulses transmitted through rock samples varying in size from laboratory specimens to mine pillars in place. Pulses are produced by electronically excited piezoelectric ceramic transducers. Special equipment components were developed by Bureau facilities; other components are commercially available. The technique permits a nondestructive, repetitive, stable, shaped pulse to be used in place of explosive caps or hammer blows. Longitudinal wave travel time measurements were taken on an oscilloscope screen; transverse wave measurements were taken under special field conditions. Results were consistently repeatable within the accuracy of the oscilloscopes utilized.

Jan 1, 1966

By Ivan F. Avery

PRODUCTION of carbon black decreased 4 percent in 1961. Output in the major producing States of Texas and Louisiana decreased 1 percent and 8 percent, respectively. Production of channel black continued downward, declining 10 percent in 1961 compared with 9 percent in 1960. Furnace black production also decreased 3 percent from 1960. Total domestic sales, however, increased 2 percent, Sales to most major consumers increased, but sales to the ink industry decreased 10 percent. Producer's stocks decreased 5,083,000 pounds during the year. Exports decreased 4 percent. SCOPE OF REPORT Carbon black is a very pure grade of quasi-graphitic carbon; particle diameters range from 50 to 5,000 angstrom units. Annual reports were submitted to the Bureau of Mines by operators of all commercial plants in the United States.

Jan 1, 1962

By P. G. Clites

This study was conducted to determine the patterns of heat transfer to water-cooled copper crucibles during vacuum arc melting. Values of heat flux from the ingot to the crucible were determined during nonconsumable electrode vacuum arc melting of zirconium and during consumable electrode vacuum arc melting of titanium) zirconium) and steel. The results of these studies con-firm the existence of a high thermal resistance between the ingot and the crucible wall which results from the shrinkage of the ingot as the metal solidifies. Maximum heat flux occurs near the top of the ingot where maximum values of heat flux of 1.4 X 106 Btu/ft2 hr were observed during small-scale consumable electrode arc melting of zirconium and titanium. The maximum heat flux for consumable electrode arc melting of 8-inch-diameter ingots was 0.5 X 106 Btu/ft2 hr. The effects of electrode material) electrode diameter) arc current) and arc potential on heat flux from the ingot to the crucible were studied. Data were also obtained on crucible wall temperatures and on the effect of very narrow annular water jackets.

Jan 1, 1967

By Dennis A. Long

Slip and fall accidents are a major cause of lost-time injuries associated with large mobile equipment in surface mines. An evaluation of the safety hazards associated with getting on and off large surface mining vehicles showed that most of the accidents occur at the point where personnel attempt to mount or dismount the machine at ground level. The major hazardous design conditions were identified as excessively flexible supports for lower steps or rungs, inappropriate ground-level-to-first-step distances, poor step designs, access designs that use vehicle components as steps or walkways, and inadequate hand- rail and guardrail designs, Additional hazards are introduced by the lack of proper maintenance of ladder hardware and the work practices of operators in carrying articles while mounting and dismounting the vehicle. This Bureau of Mines report describes the design and in-mine testing of improved access system for large mobile mining equipment.

Jan 1, 1984

By Michael T. Nigbor

The Bureau of Mines assisted the Rocky Mountain Energy Co. in a pilot-scale in situ leaching experiment at Casper, Wyo., to determine if sulfuric acid can be used as a cost-effective alternative lixiviant (leachant) for uranium in situ leaching. This experiment, which lasted more than 2 years, is the first fully documented pilot-scale operation in which the leaching-restoration cycle was completed using sulfuric acid instead of the more common carbonate-bicarbonate leachant This report describes activities at the experimental site, presents extensive geochemical data from startup to site restoration, compares laboratory and field experiments, and discusses the environmental aspects of acid leaching. The data showed that sulfuric acid is apparently an effective leaching solution. Three to five grams of acid per liter of ground water resulted in a production solution grade of 80 to 100 ppm uranium. Restoration was successful, but required extended flushing. The pH was the last chemical parameterto return to baseline, requiring about 350 days. This was longer than was predicted in laboratory simulations. The data also showed that mobilization of toxic elements such as selenium, arsenic, radium, thorium, and molybdenum stayed within reasonable limits and quickly fell back to preleach concentrations during restoration.

Jan 1, 1982

By Maria I. De Rosa

The major fire and fire injury findings for all metal/nonmetal mining categories for 1990-2001 are shown in tables 64-65. Table 66, partly illustrated in figure 22, shows the number of fires, fire injuries, fire fatalities, risk rates, employees' working hours, and lost workdays for all metal/nonmetal mining categories by time period. For all metal/nonmetal operations (including stone and sand and gravel), a total of 518 fires occurred during 1990-2001; 296 of those fires caused 308 injuries and 4 fatalities (Ewhr = 4,012 x 106 hr, In = 0.015, LWD = 36,204). Thirty fires and 26 injuries involved contractors. The greatest number of fires and fire injuries occurred at surface operations; the highest risk rate values were also calculated for surface operations. The number of fires increased during the first four 2-year time periods (1990-1991, 1992-1993, 1994-1995, and 1996-1997), then decreased during the last two periods (1998-1999 and 2000-2001). The number of injuries showed a decrease throughout the periods, accompanied by an increase in employees' working hours. Twenty-five firefighting interventions by mine rescue teams in underground mines and at least 30 interventions at surface operations were required to combat these fires. However, 45 fires destroyed or heavily damaged facilities and equipment (including 19 pieces of mobile equipment) because of failure of firefighting methods, late fire detection, undetected fires, or fire size. Ninety-seven fires were detected late, and 30 fires were undetected. The ignition sources that caused the greatest number of fires were flame cutting/welding spark/slag/flame (169 fires or 33% with 137 injuries), hydraulic fluid/fuel sprayed onto equipment hot surfaces (89 fires or 17% with 46 injuries and 3 fatalities), heat source/explosion and flammable liquids/ gas/refueling fuel on hot surfaces (98 fires or 19% with 73 injuries), electrical short/arcing (51 fires or 10% with 16 injuries), and spontaneous combustion/hot material (46 fires or 9% with 17 injuries). The flame cutting/welding spark/slag/flame source caused fires usually involving welders' clothing or oxyfuel/grease and other materials (including chute and dust collector liners, flammable liquids, belt material, crusher, hopper and shaker deck materials, washer plants, equipment mechanical components, stampler breaker, hydraulic fluid, rubber tires and hoses, gear boxes, bin feeder, dump rope cables, screen liner and screen panel, kiln and shaft material, pipelines, liquor pumps, wood pallets, electrical junction boxes, handrails, grease, refuse, shop and wood). The spontaneous combustion/hot material and electrical fires were usually detected late due to lack of combustion gas/smoke detection systems. At least 55 of the 89 mobile equipment hydraulic fluid/fuel fires became large fires (requiring 12 mine rescue team interventions in underground

Jan 1, 2004

By Thomas M. Barczak

This U.S. Bureau of Mines study evaluates factors that influence longwall support and strata interaction. The longwall system is composed of an immediate and main roof structure and three supporting foundations: longwall panel, powered roof supports, and gob waste. The main roof forms a structure that is generally supported by all three foundations, while the immediate roof acts as a beam that cantilevers from the coal face to the powered support. In most cases, shield loading involves a complex interaction of both main roof and immediate roof behavior and is a combination of loads produced from convergence of the main roof and displacements of the immediate roof caused by deformations of the cantilevered roof beam. Since the shield stiffness remains constant for all leg pressures and main roof convergence is irresistible in terms of shield capacity, the shield must be able to control the behavior of the immediate roof or floor structure for shield loading to be sensitive to setting pressures. If the goal is to minimize total shield loading, any active setting force must be offset by reduced passive shield loading to justify the active setting loads. Field data sumest that the typical reductions in passive loading do not justify the required increases in setting pressure in some applications.

Jan 1, 2010

A Helix Pressure Gauge to Indicate roof bolt loads was designed, fabricated and field tested. The gauge indicated loads between 3,000 and 15,000 pounds with a ± ten per cent error. The coat of fabrication of the gauge was estimated to be $3.39 including an assumed overhead and profit per indicator for a series production of 5,000 unite. The unit can be read on a bolt to within ± 1,000 pounds load from a distance of twenty feet.

Jan 1, 1974

By J. M. Stuve

Standard heats of formation (AH°p) of YbCl3 (c) and TmCl3 (c) were measured by solution calorimetry. Heat of solution data are given for ytterbium and thulium metals and corresponding anhydrous trichlorides in 4.360 molal hydrochloric acid. The derived standard heats of formation of YbCl3 (c) and TmCl3 (c) were -229,370 ±720 and -235,820 ±400 cal/mole, respectively, at 298.15° K. The resulting heats of formation for YbC13 and TmCl3 are about 1 kcal and 6.3 kcal more negative than previously published values.

Jan 1, 1967