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By N. S. Dalal, B. Jafari, X. Shi, M. M. Suryan

"It is well known that prevalence and severity of coal worker's pneumoconiosis (CWP) differ markedly in different regions and mines despite comparable exposures. These variations in the pathogenicity of different coal mine dusts can only partially be explained by the mineral composition of the coal mine dust and the rank of coal. Laboratory studies also do not correlate with the human experience. One major difference between human exposure and laboratory studies is that the coal miner breathes dust from freshly broken coal, while the animals or cells are exposed to stale dust. In an effort to find biochemical clues for resolving this apparent paradox, we have carried experiments to detect differences in chemical reactivities of fresh versus stale coal dust from several U.S. coal mines. Electron spin resonance (ESR) was used as a technique for the direct detection of the concentration and reactivity of free radicals. ESR measurements of freshly ground coal dusts of different ranks and composition showed significant differences in the amount and reactivities of the organic free radicals produced. The half-lives and reactivity patterns of these newly formed species of free radicals seem to correlate with the expected toxicity and pathogenicity of the dust, thereby, providing new clues to the biochemical mechanisms and pathogenesis of CWP. Similar detection of free radicals in freshly crushed quartz suggest that free radicals might play a significant role in the pathogenicity of quartz in causing fibrosis and eventually silicosis.IntroductionThe pathogenesis of coal workers' pneumoconiosis (CWP) has been an important topic of concern for decades, but the mechanism of CWP is still not understood. It is well known, for example, that the prevalence and severity of CWP differ markedly in different regions and mines despite com¬parable exposure'(1,2) but these observations can only par¬tially be explained by differences in mineral composition and rank of coal (3-5) Specifically, while epidemiological studies of coal miners indicate (1,2) that the effectiveness of coal in producing CWP correlates roughly with the rank (i.e. %,carbon content) of coal, such correlation has not been established via biological studies.(4-6)"

Mar 1, 1989

By A. J. Kraemer

[During the past several years a great deal of discussion has centered around the question of the permissible limit of sulphur content in fuels for automotive and aviation motors. Under certain conditions of operation, sulphur in motor fuels causes the formation of corrosive substances which attach bearings, wrist pins, and other parts of engines. On the other hand, in making gas¬oline from certain stocks, the gasoline fraction normally contains a relatively large proportion of sulphur compounds. By the generally used processes of reducing the sulphur content, a significant part of the gasoline fraction is lost as motor fuel, and added expenses are entailed for chemicals, labor, and other process costs. This condition has been an economic burden to some refiners of high-sulphur crudes. In some instances the treating losses have been rather severe and the treating costs relatively high, but the data presented in this paper indicate that the reduction of sulphur content of motor fuel is a problem to a relatively small number of refiners and of little or no concern to the remainder; in fact, more then 90 per cent of the 153 samples analyzed passed the Federal specification requirement, which limits the sulphur content to 0.10 -nor cent. 3 This report is based upon the results of an examination for sulphur content, Doctor test, copper strip corrosion, and color of the samples collected during January, 1930, for the twenty-first semiannual gasoline survey of the Bureau of Mines. The results of the gravity and distillation tests of the survey were published as Report of Investigations 2995. The numbering of the samples given in this report is the same' as in Report of Investigations 2995; for example, No. 25 of this report is the same sample as No. 25 of Report of Investigations 2995.]

Jan 1, 1930

By Harry R. Johnson

Laboratory experiments were conducted to study the carbon deposition characteristics of a high-gravity, paraffin-base crude oil. The results of these experiments indicate that a fuel supply adequate to initiate a combustion wave can be deposited in high-gravity-oil reservoirs. These results are significant because there has been considerable doubt whether oils over 35° API gravity are able to deposit sufficient fuel. Considered in these studies were the effects of air flux, temperature, initial oil saturation, and time on carbon deposition. Conditions that maximized carbon deposition in the laboratory and an understanding of the nature of carbon formation are shown by graphical interpretation of the data. Statistical techniques were used to design and analyze the results of the retort tests. For the same amount of laboratory work, this approach yields more information about the systems that were studied than the classical method of research presently used in many laboratories. In addition, the accuracy of calculating the effect of each variable on carbon deposition is twice that of the classical approach. This paper develops the statistical approach to research without complex mathematics, thus enabling the reader to grasp the concept of how statistics can be applied to study many complicated problems.

Jan 1, 1966

By F. S. Crawford

The average visitor to a large electric-shovel operation may wonder how electric power can be treated as carelessly as apparently it is in open-pit mining, and how the mining company can string it carelessly along the ground in great, black, hoselike cables, whereas the power company, which has learned to respect his deadly agency, keeps power lines far out of reach. This is explained by the fact that this particular kind of application of power to moving machinery requires the use of trailing cable instead of the more permanent type of construction that permits a moving contact, such as a trolley. The cables are designed to insulate fully the enclosed power lines against damage and loss of current; and employees are taught to handle them carefully, although engineers are not satisfied that the trailing cable is foolproof and are seeking constantly to improve methods and equipment to insure greater safety. In some sections they rely mainly on the construction of the cable and perfection of equipment, while in others additional precautions are taken, such as handling the cable with rubber gloves, slings, tongs, or loops. In some sections no temporary repairs are made to cables, while in others such repairs are made and later are vulcanized in the shop. At some operations the cycle of shovel duties is arranged so that cables are very seldom exposed to flying rock fragments while at others this exposure appears to be unavoidable. Methods of fastening the cable to the shovel frame and transporting the loose cable vary. Inspection and care of the cable are important in insuring its safety and durability. A limited amount of information was obtained by field engineers of the United States Bureau of lines from operators in various parts of the United States, as methods of handling electric-shovel operations differ with the districts; practices followed and equipment used in these districts are described in this circular.

Jan 1, 1936

By A. L. Engel

This report is a compilation of preliminary and, in some cases, more extensive concentration experiments by the Federal Bureau of Mines on low-and medium-grade fluorspar ores from three localities in Nevada and one in California. The work was done on samples obtained from Shoshone mine, Nye County, Valery mine, Pershing County, and the Broken Hills mine, Mineral County, all in Nevada, and Dirty Weather mine, Inyo County, Calif. These investigations were made to aid in the development of domestic fluorspar resources, in line with the Bureau's long-established program of conservation of mineral resources. The treatment methods employed in the experimental work described included simulated or "heavy-liquid" gravity concentration of coarse minerals and comparatively fine-grained minerals, and flotation concentration of finely-ground minerals. These methods were attempted in order to beneficiate the ores and produce concentrates which could be marketed readily, with as high a recovery rate as possible, while using simple treatment methods suitable for small-scale operation.

Jan 1, 1961

By R. V. Ramani, R. Bhaskar

"While the National Academy of Sciences has stated that gravimetric sampling technology for compliance purposes is adequate, research into various aspects of respirable dust control require data on many other parameters of airborne dust. These, in turn, have created the need to use many instruments, other than personal gravimetric samplers, in mi ne environments for dust measurement. There is a need to evaluate the performance of these instruments under conditions of potential use.As part of research in the Generic Technology Center for Respirable Dust, cascade impactors, gravimetric personal samplers and gravimetric samplers collecting dust using isokinetic sampling principles were employed for dust measurements under identical conditions in a mine airway. During the course of the experiments, 8-stage cascade impactors and gravimetric samplers drawing air isokinetically were located in the center of a mine airway at various stations. Two types of data were examined - concentration of dust and size distribution of the dust collected in the samplers. The data show that the amount of dust collected by an impactor is less than half the amount collected isokinetically. The size distributions of the dusts collected from the two instruments, though comparable, show a consistent difference in median diameters. The cause for this bias is examined.The paper presents and discusses the results of the tests, including the concentrations and size distributions obtained from the two instruments for different experimental conditions. There is a need to document the performance of various dust measuring devices in mine airflow conditions.INTRODUCTIONThe sampling of airborne dust in mines can be done for several purposes. Traditionally, dust sampling has been restricted to the gravimetric measurement of airborne respirable dust to comply with the regulations governing the mining industry. Instruments such as the MRE gravimetric sampler, and personal gravimetric samplers that have collection characteristics similar to the human respiratory system have been in use for the last two decades. Presently available instrumentation for the purpose of regulation have been considered adequate by the Committee on the Measurement and Control of Respirable Dust in Mines (National Academy of Sciences, 1980),"

Jan 1, 1989

By W. W. Agey

The Calico silver-barite deposits near Barstow, Calif., are a potentially important resource. Exploration performed by two major mining companies out-lined large tonnages of ore that assayed at 2 to 3 ounces of silver per ton and 7 to 15 percent barite. Laboratory beneficiation work was done by the Bureau of Mines on four samples to develop methods for recovering the silver and/or barite. Cyanidation recovered from 47 to 60 percent of the silver from ore ground to approximately 100 percent minus 325 mesh. Salt roasting minus 10-mesh material, followed by regrinding and cyanidation, recovered 75 to 85 percent of the silver. From 75 to 90 percent of the barite was recovered in a plus 92-percent barite product from either the natural ore or from cyanidation residues. Salt roasting before cyanidation precluded recovery of the high-grade barite concentrate from the leach tails.

Jan 1, 1973

By O. E. Traubert, E. G. Meiter

"The daily sulphur dioxide content of the air at the Pittsburgh Experiment Station of the Bureau of Mines was determined by the bureau at the request of Committee D-14 on Screen Wire Cloth of the American Society for Testing Materials. The purpose of the investigation was to obtain data for use in interpreting screen-corrosion tests, which were conducted simultaneously and jointly by the committee4 and the Bureau of Mines.The plan of this investigation was to vale a single daily determination, except on Sundays and holidays, of the SO2 content of the atmosphere at the exposed test screens, for a period of one year. No attempt was made to determine the variation during the day, except on the morning of October 15, 1927, when the atmosphere was unusually foggy and smoky. Several successive determinations were made on that date to ascertain changes in the SO2 as the morning haze disappeared. The SO2 determinations were begun on August 11, 1927, and continued until August 11, 1923.The Pittsburgh Experiment Station of the Bureau of Mines is in a residential section about 3 miles east of the central or main business district of Pittsburgh. The air samples were taken on the roof above the auditorium, or the center rear of the building. This was also the place where the pieces of screen were placed for corrosion tests. The height was about 40 feet above ground level. Several sources of considerable smoke and SO2 are in the immediate vicinity. On the west side of the building is a double-track railroad. At this point the line runs through a cat below the level of the building. The horizontal distance between the air-sampling position and the railroad tracks is about 400 feet, and the vertical distance about 70 feet. The power plant for the Bureau of Mines building is about 250 feet south of the sampling position. About 1000 feet farther to the south are the engineering building and power plant of Carnegie Institute of Technology, and 1/4 mile to the southwest is the power and heating plant for the Carnegie Library and Museum. About 1 to 2 miles farther south and also southwest"

Jun 1, 1930

By John E. Shelton

The growing interest in beryllium as a structural material, and its in-creased use in recent years for atomic energy application, have led both government and industry to express concern over the inadequacy of the beryllium resources in the United States and the free world. Contemplated and proposed uses for this unique material will surpass the capacity of the domestic beryllium mining industry to supply raw material, which is presently extracted from relatively small deposits by hand sorting. The need for a simple beneficiation process for beryl ores has long been recognized by the Bureau of Mines, but to date no single process has proved satisfactory for treating deposits containing a sufficient tonnage of beryl ore to warrant commercial exploitation. As a part of the Bureau's continuing effort to develop an economical recovery process, this report describes flotation research on samples of beryl-bearing pegmatites from the George Roebling mine in Connecticut, and the Colony mine in New Hampshire. The study resulted in two methods of treatment to which the ores responded reasonably well.

Jan 1, 1961

By James C. Cawley

This National Institute for Occupational Safety and Health study was conducted to focus future research on the most significant electrical problems in the mining industry. Data from 1,926 mine electrical accidents (including 75 fatalities) that occurred between 1990 and 1999 were studied. Coal and metalnonmetal operator- and contractor-reported data are presented. All data used in this analysis were MSHA closeout data, except 1999, which were preliminary data.

By N. S. Dalal, X. Shi

While it is known that vanadate and related compounds of pentavalent vanadium ( V (V)) exert potent toxic effects on a wide variety of biological systems, the underlying biochemical mechanism is still not fully understood ( 1- 3). One of the pathways is thought to involve the oxidation of NAD ( P) H. Thus, considerable effort has been devoted to finding the mechanism of NAD ( P) H oxidation by Vcvi (1-15). Erdmann et al. (5) first noted that vanadate stimulated the oxidation of NADH by plasma membranes and attributed this effect to a membrane containing NAD(P)H-dependent V(V) reductase. Later studies by Liochev and Fridovich indicated that endogenous superoxide ( 02 ) plays a central role in this reaction ( 4, 12, 13) . They proposed that NAD ( P) H dehydrogenases or oxidases produce 02, which causes VCV ) to stimulate NAD ( P) H oxidation via the following free radical chain mechanism ( 4, 12, 13) :

Mar 1, 1992

By R. D. Leitch, W. P. Yant

"In the course of another investigation4 during 1926 and 1927, samples of water collected from a few abandoned coal mines indicated that their drainage was usually lower in acidity than water from active mines in the same locality. In order to determine whether this condition might have a bearing on the advisability of sealing abandoned mines, a number of such mines were visited, samples of drainage were collected, and as much information- as possible was obtained from officials of the mining companies and older residents of the district. The results of this work are the basis of the present report.The authors are indebted to E. W. Robertson, F. F. Spowart, J. H. Nagle, and W. D. Adams of the Northwest Mining & Exchange Co.; E. M. Fasset, Fred Lane, Wm. Humphreys, and Dr. T. A. Hutchison of Brockway, Pa.; C. W. .Faulk of the Shawmut Mining Co.; James Hau of Kersey, Pa., and to others for information received; and to Dr. R. R. Sayers of the Bureau of Mines, under whose direction the work was conducted.The Lower Kittanning is the most important bed in the locality studied. A great many of the abandoned mines examined are in this bed, and nearly all of the present active ones are. The Upper Freeport bed is also mined to some extent, and a number of the abandoned mines formerly worked this bed. As only three active mines are now (1927) working the Upper Freeport, the comparison of acidities is necessarily limited. Of these three, one had been idle since 1922 until shortly before it was sampled.The location of most of the mines was already known from previous work, but some of them had to be located by following up streams known to contain acid waters. A sample of the- outflow was collected in self-sealing bottles known as ""citrate bottles"" for the determination of dissolved oxygen by the Winkler method.5 Another sample was taken for the determination of acidity according to standard methods of water analysis.6 Ferrous iron was determined at the mine or very soon after taking the sample by titrating with a standard solution of potassium permanganate in acid solution. The hydrogen-ion value was determined by a standard double-wedge comparator.7From the total acidity values in each sample, which are the most important values, the total iron was calculated on the assumption that acidity as sulphuric acid was due to dissolved ferrous sulphate. This assumption is commonly made for mine waters, but is inaccurate to the extent that free acid is already present, and some of the iron is present as ferric, rather than ferrous, sulphate. The amount of ferrous sulphate may be a rough measure of the extent to which oxygen is lacking within the mine. The permanganate titrations just mentioned showed what part of this total iron was in combination as ferrous sulphate, and the difference .was assumed to be that in combination as ferric sulphate, after correcting for the amount of free acid already formed as shown by the titration values."

Oct 1, 1928

INTRODUCTION The pager phones used in many underground coal mines are battery- operated, party-line telephones with provisions for loudspeaker paging. The system is two-wire, non-polarized, and is operated by self-contained batteries. Many of the individual units are certified as permissible. Requirements for installation are specified in state and federal regulations, such as in the Code of Federal Regulations, Title 30, Mineral Resources, Part 75. The major federal regulations that affect communication in coal mines are noted below, with a brief description of the subject matter in each of the relevant paragraphs. Refer to the cited paragraphs of Title 30 for explicit details of these regulations. (This brief description is for reference purposes only.) Minimum Requirements (paragraphs 75.1600, 75.17 13-2, and 75.1003-1) Approved telephone or two-way communication will be provided between the surface and each main shaft landing and each working section ; to the nearest medical assistance; and shall be protected from contact with trolley wires or trolley feeder wires. Installation Requirements (paragraphs 75.5 16-2, 75.52 1, and 77.508-1 ) Communication wires will be supported on insulated hangers, attached to messenger cables, or buried, to protect against mechanical damage ; installed opposite trolley wires; and insulated near power conductors . . . each cable will have lightning arresters within 100 feet of going below ground . . . and arresters will be provided wherever telephone wires enter a building. Wire and Cable Requirements (paragraphs 75.5 16-2, 75.5 17, and 75.52 1) Communication cable means two or more insulated conductors, covered by an additional abrasion-resistant covering; power wires and cables shall be adequately insulated and fully protected; and lightning arresters shall be connected to low-resistance grounds, more than 25 feet from neutral grounds.

Apr 1, 1975

By R. H. Nicholas

Shuttle cars have undeniably proved their worth as a means of transporting coal underground; however, several factors have arisen in connection with their possible improvement. This report .discusses the effect of shuttle cars that employ rough-tread and smooth-tread tires on mine roadbed, the amount of dust thrown into suspension by the use of such tire treads, and the service rendered by each type of tire. Involved, also, in this study are observations on the use of different amounts of calcium chloride on the haulageways.

Jan 1, 1949

By Andrew B. Cecala

The U.S. Bureau of Mines has designed and tested a system called the Bag and Belt Cleaner Device (B&BCD) to reduce dust levels in and around the bag conveying and stacking process. The device physically cleans either 22.7 kg (50 lb) or 45.4 kg (100 lb) paper bags by using a combination of brushes and air jets. It is completely self-contained and is kept under negative pressure by a baghouse to ensure that dust and product removed from the bags during cleaning does not flow into the work environment and contaminate workers. The bags travel through the device on a chain conveyor, which permits any product or dust cleaned from the bags to fall into a hopper at the bottom of the device and be recycled back into the process via a screw conveyor. Once exiting the B&BCD, the outside of the bags and the conveyor are essentially product and dust free. The B&BCD was evaluated at two mineral processing plants to determine reductions with the device in use. The results of both field evaluations showed that the amount of product removed from the outside of the bags varied from 77 to 93 pet.

Jan 1, 2010

By E. A. Loria

High-quality sheet of electrowon molybdenum was attained by a sequence of procedure on pressed and arc-melted crystalline powders. The procedures included high-temperature, high-vacuum sintering treatments and the use of metal deoxidizers instead of carbon to improve the mechanical properties of the molybdenum sheet. Rolled sheet 60 mils thick was evaluated by tensile and bend tests, hardness measurements, microstructures, and recrystallization treatments. After stress relieving, yield strength ranged from 85,000 to 110,500 psi (0.2- percent offset) and ultimate strength ranged from 87,200 to 117,250 psi with 4.5- to 25-percent elongation observed for arc-melted sheet, and 5.0- to 23- percent elongation observed for powder metallurgy sheet. In room temperature bend tests the sheet yielded plastically, indicating that the ductile-brittle transition point was below room temperature. The diamond pyramid hardness (DPH) of the molybdenum sheet changed from 214 to 293 DPH for the stress-relieved condition to 177 to 185 DPH for the fully recrystallized condition. The brittleness of recrystallized molybdenum, reported by other investigators as characteristic of sheet prepared from commercial-grade hydrogen-reduced powders, was not in evidence. Recrystallized tensile specimens pulled at room temperature had an average elongation of 31 percent.

Jan 1, 1966

By E. G. Valdez

Laboratory research demonstrated that ceramic wall and floor tile can be produced from electric furnace phosphorus slags composed of calcium silicates. Grinding the slag in a pebble mill, followed by magnetic removal of deleterious magnetite, produced a raw material that could be compounded and formed into wall tile by dry pressing, sintering, and glazing. The effects of process variables such as forming pressure and sintering temperature were investigated. Wall tile bodies produced by this method were comparable to commercial tile. The tiles were readily glazed to a smooth shiny finish and met ASTM Specifications C34-62 for structural clay load-bearing tile. The estimated cost of producing wall tile by this method compared favorably with the retail market value for similar wall tile. Addition of borax or other additives to the ground slag followed by dry pressing and firing likewise produced a commercial grade of floor tile.

Jan 1, 1974

By C. A. Komar

The Bureau of Mines conducted experiments on one synthetic and three natural sandstone samples to investigate the effects of acoustic energy on the flow of brine in porous media. Ultrasonic energy at a frequency of 20 kc per second and an intensity of 55 watts per cm2 was irradiated in the direction of the fluid flow and in the opposite direction for distances of 1/2 and 2 inches between the vibrating device and the sample face and under conditions of suppressed and nonsuppressed cavitation. Forty tests were conducted: 32 with a pressure differential of 0.64 psi across the samples, 2 with 5 psi, and 6 with 15 psi. Acoustic waves altered the rate of flow of the brine through the samples, but this effect was observed only at low differential pressures and from a practical point of view was insignificant. As a result of irradiation, however, the samples exhibited reduced permeability. This reduction was probably caused by the shifting of solid particles dislodged by the acoustic waves.

Jan 1, 1967

By Jon C. Volkwein

The U.S. Bureau of Mines has developed a method to measure methane and other gases during the auger mining of coal. An intrinsically safe commercial gas detector with a built-in data logger was mounted in the center of the hollow conveying auger. A sampling head through the wall of the auger conducted a gas sample to the detector. Results showed that gas levels can be monitored on a continuous basis during the auger mining of coal and the data retrieved upon completion of the hole.

Jan 1, 1994

By James V. Kelly

During the winter of 1946 and the spring of 1947, the Bureau of Mines conducted an investigation and drilling program in the vicinity of the village of Fairplay, Wis. Fifteen diamond drill holes totaling 2,457.6 feet of bore were completed. This work was part of a general study of the zinc-producing area of southwestern Wisconsin and had the particular purpose of investigating a structural trend, determined by the Federal Geological Survey, in an area some distance from known ore bodies or active mines.

Jan 1, 1948