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By Jr. Watts, B. K. Cantrell, D. H. Carlson, K. L. Rubow, S. T. Bagley

"Permissible exposure limits (PELs) have been established for gaseous pollutants, carbon monoxide (CO), carbon dioxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and some gas-phase hydrocarbons emitted in diesel exhaust. There is, as yet, no PEL recommended for diesel exhaust aerosol (DEA), nor is there a standard method for sampling this aerosol.The University of Minnesota and the U.S. Bureau of Mines have collaborated to develop a personal diesel exhaust aerosol sampler (PDEAS) which utilizes size-selective inertial impaction and gravimetric analysis. During the field tests of this sampler, numerous air quality measurements were made in underground coal mines that use diesel equipment.The mine mean DEA concentrations for the five mines surveyed, determined with the PDEAS in the haulageway, was 0.89 mg/m3, with a standard deviation of 0.44 mg/m3. DEA contributed 52 % of the respirable aerosol at this location.In three of the mines filter samples were collected for DEA-associated polynuclear aromatic hydrocarbons (PAHs) and biological activity determinations. Two of the mines were also monitored for the major gaseous constituents found in diesel exhaust. In general, the PAH and biological activity levels were similar for all three mines, and indicate that up to 25 % of the haulageway concentrations may be contributed by outby diesel vehicles. Measured concentrations of CO, CO2. NO, NO2, and SO2, were well below regulated levels.INTRODUCTIONDiesel exhaust contains pollutant gases, such as carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and gas-phase hydrocarbons, as well as DEA. Much of the health-related concern focuses on DEA and associated organic compounds (Watts, 1992a). A wide variety of these PAHs have been identified and some are known carcinogens and/or mutagens. The U.S. Mine Safety and Health Administration (MSHA) has proposed new PELs for these and other contaminants (MSHA, 1989). MSHA has also published an advance notice of proposed rulemaking to establish a separate PEL for diesel particulate (MSHA, 1992)."

Nov 1, 1995

By Joseph A. DeCarlo

For the first time the Bureau of Mines is combining, in one report, comprehensive tabulations on both beehive and slot-type ovens. This publication presents statistical data on the number and capacity of all such coke ovens in the United States on December 31, 1957. Combining data on both types of ovens should prove helpful to those interested in keeping abreast of the latest changes in carbonizing capacity, particularly since the coke has similar properties and uses. Annual reports furnished to the Bureau of Mines by coke-oven operators shared that 78 oven-coke plants were operating in 22 States on December 31, 1957. This was a decline of one plant from December 31, 1956, as the Republic Steel Corp. took the ovens at Canton, Ohio, out of production on December 17, 1957, for dismantling and rebuilding in 1958. Total oven-coke capacity was 80,299,400 tons in 1957.

Jan 1, 1958

By Ludwig Schmidt

The economic value of reducing the evaporation losses of crude oil and of gasoline is so well founded that the petroleum industry is constantly seeking new and improved storage tanks and methods of handling its products to further reduce these losses. A comparison of the methods and apparatus used in handling and storing crude oil and its products today with those in general use 10 years ago would show that an oil tank is no longer simply a container for holding liquid, but is now considered an important piece of equipment which if, subjected to constant inspection and care. In fact, the modern vapor-tight tank often requires as much care as a boiler or pump when one considers Its various component parts such as vapor-tight gage hatches and thief-hole covers, vacuum and pressure relief valves, swing line apparatus, vapor-recovery systems, insulation, cooling devices, and often automatic gaging devices. As an auxiliary to the physical equipment of the tank itself the subject of paints and paint colors is now given considerable attention. In addition to vapor-tight tanks and auxiliary equipment, other types of tanks for reducing, evaporation which are new to the industry have also been developed and placed on the market within the past few years. The development of the floating roof type was an innovation in tank construction, directed toward the reducing of evaporation losses. This type of roof rides on the surface of the oil and thus eliminates all vapor space. It is especially valuable for working tanks.3 A recent development in tank construction is a new type of tank roof known as the diaphragm or "breather roof," Which practically eliminates the movement of air-vapor mixture from a storage tank filled with oil. It is of especial value for use on tanks in which oil is stored over long periods.

Jan 1, 1930

By Lawrence W. Scott

The performance of RETIMET metal foam as a flame arrester on explosion-proof enclosures was investigated by the U.S. Bureau of Mines both in laboratory tests and at the U.S. Mine Safety and Health Administration's (MSHA's) Approval and Certification Center, Triadelphia, WV. The objective of this research was to develop a permissible pressure vent for use on lightweight, vented, explosion-proof enclosures. In laboratory tests, four grades of RETIMET, a stainless steel foam material, were evaluated: (1) 45 NC-7, (2) 45 NC-13, (3) 80 NC-7, and (4) 80 NC-13. Explosive gas mixtures were prepared by a dynamic flow system. Ignition was by a low-voltage arc. Each grade of RETIMET metal foam successfully arrested the flame front in all methane-air tests. To evaluate RETIMET metal foam on large, commercial size enclosures,a multi compartmented enclosure was designed and tested in MSHA's explosion gallery in Triadelphia, WV. Extensive explosion testing revealed that a minimum vent-area-to-enclosure-volume ratio of 11.33 in2/ft3 is required to keep internal pressure rises below 3 psig. The RETIMET metal foam functioned satisfactorily in all tests as evidenced by the absence of external ignitions.

Jan 1, 2010

By R. W. Van Dolah

An important function of stemming used to confine explosives in shot holes in underground coal mines is to minimize the chance of ignition of firedamp or coal dust by the detonation products. Until 1952, the Bureau of Mines approved only the use of fireclay or similar incombustible material for stemming permissible explosives. At least 2 feet of stemming were required except in holes less than 4 feet deep; in such short holes the stemming was required to be half the depth of the hole. Over the years, several special stemming devices have been proposed in the United States as substitutes for fireclay. Many economic and safety advantages were claimed for these devices, but only one approved device has been marketed in this country. Bureau requirements for stemming explosives in coal mines were modified at that time to permit the approved stemming device to be used as a substitute for the required fireclay.

Jan 1, 1961

By John Furness Park

This paper, which describes the mining methods and practices at the Jarbidge mines of the Elkoro Mines Co., is one of a series of papers being issued by the United States Bureau of Mines on mining methods and costs in various districts throughout the United States. LOCATION AND HISTORY The Elkoro Mines Co.'s property is located at Jarbidge in the northeast corner of the State of Nevada (fig. 1). The camp is 9 miles south of the Idaho line; the nearest railroad point is 70 miles to the northeast at Rogerson, Idaho. A road leading to the south and connecting with Deeth, Nev., is passable during the summer months; the heavy snowfall which generally takes place early in the winter usually closes the road until the first of July.

Jan 1, 1931

By Bruce D. Hanson

The Bureau of Mines conducted a series of ignition tests with two types of conical bits (plumb bob and pencil) used on continuous mining machines, to determine their ignition potential at various bit speeds, cut depths, and wear conditions. The tests were conducted using single bits mounted on a 34-in-diam drum in a Bureau ignition test facility. The bits impacted blocks of Berea sandstone in a 6.5 pet methane atmosphere at various bit speeds and cut depths. In a new condition, the plumb bob bits were considerably more incendive than the pencil bits, causing ignitions in 32 of 35 tests at 60 rpm, compared with ignitiolls in 2 of 22 tests for the pencil bits. The results from new bit testing also show that reduction of bit tip velocity to 180 fpm does not eliminate ignition potential. When subjected to progressive wear, bits of both types were more incendive when they were locked in place, unable to rotate, than when they were free to rotate.

Jan 1, 1983

By Michael P. Moore, Christopher J. Rise

"Over the past twenty years, there have been numerous studies which have attempted to correlate the prevalence of Coal Workers' Pneumoconiosis (CWP) with different characteristics of the coal seam. Some investigators have tried to find a relationship, or the lack of a relationship, between the rank of coal seams and the incidence of CWP. Others have attempted to show that there is a positive correlation between the mean mass of respirable dust in the mine atmosphere and the prevalence of CWP. Still others have tried to determine the influence of the quartz content of respirable dust on the incidence of CWP. Unfortunately, many of these different investigations have conflicting conclusions.One area of research with conflicting conclusions deals with the relationship between the rank of the coal and the incidence of CWP. For example, an inves¬tigation conducted in Pennsylvania and West Virginia coal mines concluded that the prevalence of CWP increases with an increase in coal rank (1). A study in Great Britain also observed a close relationship between the rank of coal and the prevalence of CWP (2). However, another study involving 312 Appalachian coal miners concluded that the association between coal rank and CWP might be fortuitous and that other factors may be more important (3). In addition, an investigation involving 2,600 miners during a period of twenty years in Great Britain established that there is only a weak correlation between the prevalence of CWP and the rank of the coal (4). Consequently, it appears that there is still uncertainty as to whether or not the rank of the coal seam has an influence on the development of CWP.Another area of investigation concerns the relationship between the mean mass of respirable dust present in the mine atmosphere and the prevalence of CWP. A study involving 4,122 miners over a period of ten years in Great Britain noted a high correlation between the mean mass of respirable dust and the incidence of CWP (5). Another investigation involving 3,154 British face workers con¬cluded that the overall mass of respirable dust is the factor most closely related to the ten-year attack rate of CWP (6). However, a study conducted in thirty-one mines in the United States concluded that it is doubtful that the quantity of respirable dust alone is responsible for the difference in the prevalence of CWP (7). Even though there are conflicting conclusions, there are many more investigators who confirm, rather than deny, the relationship between the mean mass of respirable dust and the development of CWP.The third subject of investigation is the role of quartz in the incidence of CWP. For example, two studies in Great Britain concluded that the quartz content in coal mine dust has no relationship to the prevalence of CWP (8,9). But a study involving 312 Appalachian coal miners revealed that the level of exposure to free silica plays an important role in the development of CWP (10). Once again, the conclusions reached by different researchers are conflicting.Probably the most important factor in the discrepancy among the studies is the variability among different coal mines. A mine operating in an inherently ""dusty"" seam may have a low concentration of respirable dust while a mine operating in a less dusty seam may have a high concentration of respirable dust. This discrepancy is a result of variables such as the effectiveness of ventilation or the efficiency of the water sprays. Consequently, it is very difficult to compare the dustiness of different coal seams by in-mine measurements of the respirable dust concentration. A laboratory test would more accurately characterize a coal seam according to its respirable dust production."

Jan 1, 1988

By W. L. Schmidt

The effect of a water-repellent film in sandstone cores on the effective permeability-saturation relationship was investigated as part of a cooperative research program between the Bureau of Mines and the American Gas Association. The repellent film was formed by the reaction of methyltrichlorosilane3 with the connate water in the core. Other researchers have reported on the use of silicone chemicals to alter the flow characteristics of porous media (1-3, 5-7, 9, 10).4 The previous studies, however, dealt almost entirely with oil-water or oil-gas systems and not with water-gas systems. The primary purpose of this study was to determine the feasibility of using silane to retard the influx of water into natural-gas storage wells and to determine the necessary requirements for achieving this result. The success or failure of silane treatment as a remedial measure depends on its effect on gas-production rate and attendant water production.

Jan 1, 1961

By David E. Fogelson

The breakage of rock by explosives depends largely on the ability of an explosive to transfer its stored potential energy to the rock as strain energy. Therefore, the relative rock-breaking abilities of explosives can be determined indirectly by determining the relative amounts of strain energy transferred to the rock at the time of detonation. This report presents experimental data on the strain energy contained in explosion-generated strain pulses in a granite gneiss. Six explosives were tested. The scaled total radial strain energy Es/W flowing outward through a spherical shell of scaled radius R/W1/3 surrounding the point of detonation was found to follow an exponential decay propagation law of the form [ ]

Jan 1, 1959

By E. J. Matson

From February until July 1943 the Bureau of Mines conducted an exploration project at the Majuba Hill mine to determine tonnage aria grade of the copper and tin ore and to search for extension of the mineralization. The work comprised sampling, long-hole drilling, underground excavation, and ore-dressing test.

Jan 1, 1948

By Albert S. Konselman

This paper describes the mining methods and operating costs for 1938 at the South Burns shaft, situated in the Cripple Creek district, Colorado. The shaft is operated by Golden Conqueror Mines, Inc., through which portions of the properties of the Acacia Cold Mining Co., The Free Coinage Gold Mining Co., and The United Gold Mines Co. are worked under lease. During 1938, 30,773.61 dry tons of ore averaging $9.59 in gold per ton was mined. Of this, 10,138.439 tons averaging $10.65 per ton was produced on company account, and 20,635.171 tons averaging $9.05 per ton was produced by "split-check" lessees.

Jan 1, 1940

By John A. Organiscak

The Bureau of Mines conducted a survey of eight shearer longwall operations to identify factors that affect respirable dust generation from longwall roof supports. The longwalls surveyed were in coal seams located in different geographic regions of the United States. Data were collected on mining (geologic) conditions, support design, operational characteristics, and amount of respirable dust generated from roof supports. Analysis indicated that mining conditions are the main factors that affect the generation of dust during roof support movement. Both roof strength and depth of cover above the coal seam showed relationships with the amount of support dust generated. Several practices are currently employed to effectively control roof support dust; however, some of these controls are limited. More research and development is needed to improve dust control technology for longwall roof supports.

Jan 1, 1985

By Kenneth M. Earl

In its investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling at the New Galena Deposit in an endeavor to find an additional source of supply of lead. In Bucks County, lead and zinc minerals have been found in shales over a largo area west and northwest of Doylestown. Considerable mining has been done in the vicinity of New Galena on the North Branch of Noshaminy Creek, 3 miles northwest of Doylestown. It has not been possible to obtain a satisfactory history of the New Galena mine, as there is much disagreement in statements. Most of the mining was done in open pits. Two shafts were sunk to shallow depth; one of these became part of the main pit' which is 256 foot long, 50 to 75 feet wide, and 20 to 44 feet deep. Small pits 8 to 10 foot square wore sunk on the ore zone, which extends some 1450 feet to the southwest. The rock containing the minerals is either black or gray shale. The gray material closely resembles limestone. The following minerals have been reported from the mine: quartz, ankerite, calcite, galena, sphalerite, pyrite, chalcopyrite, and bornite. Some of the galena has yielded 10 to 15 ounces of silver and 10 cents in gold per ton. The average grade of the ore as mined is not known. To investigate the downward extension of the ore shoot, the Bureau drilled two holes aggregating 373.9 feet, No additional ore was developed by this work.

Jan 1, 1950

By D. W. Scott

Thermodynamics is a powerful tool for investigating rotational isomerism in substituted ethanes and related molecules. Accurate calorimetric data can be interpreted to give information, not only about the energy difference between conformations, but also about the shape of the potential barrier hindering rotation from one conformation to another. However, a deterrent to this use of thermodynamics is the labor required to calculate the contributions to the thermodynamic functions for assumed potential functions. Tables of thermo-dynamic contributions for appropriate potential functions can eliminate that labor and greatly facilitate the thermodynamic study of rotational isomerism. In this research, tables of contributions to the thermodynamic functions were compiled for two potential functions typical of some commonly encountered examples of rotational isomerism. TYPES OF POTENTIAL FUNCTIONS Potential function 1, illustrated in figure 1, A, has two equal minima higher than the third. It has the general shape of the barrier to internal rotation in n-butane, for example. The trans conformation of n-butane has the lowest energy, and the two skew or gauche conformations have equal but higher energy. Potential function2, illustrated in figure 1, B, has two equal minima lower than the third. It has the general shape of the barrier in 2-methylbutane, for example. The two C1 conformations of 2-methylbutane have equal energy much lower than the assumed Cs conformation, which has not been observed spectroscopically.

Jan 1, 1962

By F. W. Lane

Some months ago the Bureau of Mines began research of a fundamental character on sulphur in petroleum. In the course of this work, the usual qualitative test for sulphur in organic compounds1 was applied to certain oils that were believed to contain approximately 0.5 percent sulphur. No sulphur was found, and, as a check on the qualitative test, the oils were subjected to quantitative determination of this element by the oxygen-bomb method.2 The sulphur content of the oils ranged from 0.10 per cent to 0.50 per cent. This experience led to further trial of the qualitative test for organic sulphur, both on the oils mentioned above, and on common sulphur-containing organic substances. No difficulty was experienced in detecting the element in the latter, but with the petroleum oils the test, as usually performed, could not be relied upon to detect less than 0.60 per cent of sulphur consistently. The use of mechanically polished pure sheet copper for the detection of free sulphur, hydrogen sulphide, and perhaps other sulphur compounds has been recommended.3

Jan 1, 1927

By T. H. Jeffers

The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials such as sphagnum peat moss for extracting metal contaminants from waste waters. The beads, designated as BIO-FIX beads, have removed toxic metals from over 100 waters in laboratory tests. These waters include acid mine drainage (AMD) water from mining sites, metallurgical and chemical industry waste water, and contaminated ground water. Following the laboratory studies, cooperative field tests were conducted to evaluate the metal adsorption properties of the beads in column and low-maintenance circuits, determine bead stability in varied climatic situations, and demonstrate the beads' potential as a viable waste water treatment technique. Field results indicated that BIO-FIX beads readily adsorbed cadmium, lead, and other toxic metals from dilute waters; effluents frequently met drinking water standards and other discharge criteria. The beads exhibited excellent handling characteristics in both column and low-maintenance circuits, and continued to extract metal ions after repeated loading-elution cycles. Based on laboratory and field data, cost evaluations for using BIO-FIX technology to treat two AMD waters were prepared. Operating costs for BIO-FIX treatment, which ranged from $1.40 to $2.30 per 1,000 gal of water treated, were comparable with chemical precipitation costs.

Jan 1, 2010

By Marcia L. Harris

The National Institute for Occupational Safety and Health (NIOSH), as part of its continuing research program for evaluating coal dust explosion hazards, has investigated several areas in which current practices may need to be updated in order to adequately protect mines against coal dust propagated explosions. In the United States, current rock dusting requirements remained largely unchanged since 1969. US Title 30 Code of Federal Regulations Section 75.403 is based on a coal dust particle size survey performed in the 1920s and later was supplemented by full-scale testing of the rock dust ability to inert a coal dust explosion. NIOSH recently conducted a comprehensive survey of US underground coal mines to determine the range of coal particle sizes found in dust samples collected from the mine entries. Due to advancements in technology and modern coal mining techniques, the current coal dust particles in intake airways are significantly finer than those found in the mines in the 1920s. According to past full-scale dust explosion test results, the current rock dusting practices used in today?s mines to inert a coal dust explosion may not be adequate. Other closely related issues such as rock dust testing methods and sampling procedures are discussed.

Jan 1, 2009

By J. W. Paul

This circular is one of a series of papers4 on coal-mining methods and costs which are being prepared through the sponsorship of the U. S. Bureau of Mines for the purpose of presenting information on present mining methods and certain features which govern costs, safety, and conservation. The methods employed are influenced by natural local conditions with respect to the thickness, character, and dip of the coal bed, the nature of the roof and thickness of the overbearing strata, and the means employed for roof support and its control.

Jan 1, 1929

By G. L. Neumann

The Andover-Sulphur Hill iron mines in Sussex County, N. J., have a production record extending over 100 years. The last production recorded was about 1880. These mines produced high-grade ore of two types: Bed ore (hematite) and blue ore (magnetite. Some sulfides (lead, zinc, and copper) were found underlying the iron deposits. Data as to size and grade of these sulfide bodies are very sketchy, Toward. J. Hewitt of Elizabeth, N. J., lessee of the Sulphur Hill mines from 194045, prospected for lead, zinc, and copper. .His Only production was several hundred tons of low-grade iron ore, which was crushed and used as heavy aggregate to make concrete blocks for ship ballast. In October and November 1942 made a magnetic survey of this area and bored six-diamond-drill holes with the dual objective of prospecting for sulfides and testing for extensions of the iron-ore deposits indicated by the magnetic survey. In 1944, an iron-mining company examined this property and diamond-drilled seven holes Between December 1949 and March 1950, the Bureau Of Mines in search of sulfide deposits, bored three additional diamond-drill holes. Two of these were on the Sulphur Hill tract and one on the adjoining Tar Hill tract.

Jan 1, 1952