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By R. L. Grayson, W. E. Wallace, J. W. Stephens, M. D. Attfield, P. S. Brower, V. Vallyathan, M. J. Keane, J. C. Harrison

Pure respirable quartz is a known pathogenic agent for lung disease. However, for mixed dusts, neither mineralogical nor in vitro cytotoxicity assays unequivocally predict the contribution of quartz to their pathogenic potential.First, although Coal Workers' Pneumoconiosis (CWP) and Progressive Massive Fibrosis (PMF) prevalence have been found to correlate with total respirable coal mine dust exposure, and with coal rank (Attfield and Morring, 1992), epidemiological studies generally have not found the quartz component of coal mine dust as measured by X-ray diffraction or infrared spectroscopy (each of which essentially measures the mass-percent quartz in a bulk sample) to be clear predictors of CWP prevalence or incidence (Walton et al., 1971). Second, the properties which distinguish the extreme fibrogenic potential of quartz are not revealed by conventional in vitro bioassay comparison with other silicate mineral dusts. As an example, quartz and kaolin (aluminosilicate) clay in vitro cytotoxicities are comparable for lavaged primary pulmonary macrophages.The studies discussed here address these two anomalies from a general hypothesis that the pathogenic activity of respired quartz particles is associated with properties of, and interactions with, the particle surfaces. One factor in the expression of toxic activity by a particle surface is the biological availability of that surface. Anomalous lack of correlation of disease prevalence with mass percent quartz in exposures to some mixed composition respirable-sized dusts suggests that individual particle surface features, invisible by bulk sample mass analysis, may alter the biological availability of a fraction of quartz particles in a dust. For pure-surfaced mineral particles, the comparably strong prompt membranolytic activities of quartz and kaolin in vitro suggest that upon deposition of such particles in the lung there must be other interactions with particle surfaces which distinguish quartz. This might be due to toxic surface-associated sites specific to silica, or to interactions of other sites on other mineral particles which affect the biological availability of their toxic functional groups. For example, alurninol groups on clays affect the availability or activity of adjacent silanol groups. Surface activities which distinguish quartz pathogenici ty might be manifest in one or more of the sequential interactions upon deposition in the lung; first with the pulmonary surfactant system, then with extracellular and phagolysosomal enzymatic digestive processes, or with subsequent cytotoxic processes.

Dec 1, 1995

By N. F. LeJeune

For a number of years the Bureau of mines has conducted semi-annual surveys to determine the changes in the characteristics of the motor gasoline being sold in the United States. The Bureau of Mines surveys, from April, 1917, to January, 1943, indicated a progressive decrease in the end point range. The survey for July, 1923 showed an interruption in this progressive decrease. This interruption, as shown in Table 1, in the line marked "Difference," was apparently a definite one, for the data obtained in the surveys of July, 19233, January, 19244, and the present one, apparently substantiate it. The figures in Table 1 were obtained by averaging the end points of the least volatile and most volatile samples of gasoline. For example, of 850 samples analyzed in 1919, the 10 per cent (85 samples) having the highest end points and the 10 per cent having the lowest end points were grouped, and the end points of each group averaged. These averages are represented in the table as the "Maximum 10 per cent" and the ?Maximum 10 per cent," respectively. The same scheme was used on the succeeding surveys.

Jan 1, 1924

By B. T. Brady

Laboratory measurements by the Bureau of Mines indicate that failure in dry rock specimens measuring approximately 13 cm in length is preceded by tilt anomalies lasting a few milliseconds. The tilt behavior is qualitatively similar to that reported to precede earthquakes. Test results suggest that the time duration of this tilt anomaly for laboratory specimens of this length is independent of rock type, in agreement with theoretical predictions and other experimental data on rock failures including earthquakes.

Jan 1, 1975

By C. W. Owings

When explosions have occurred in mines where rock dust has been used to some extent, generally to a very limited extent, the press has immediately characterized those mines as "rock-dusted." To persons familiar with the method of rock-dusting, it is apparent that if rock-dusting is done properly, if all mine surfaces are rock-dusted to within at least 40 feet of the faces of rooms and entries, and if the incombustible content of the dust is more than 65 per cent, there is little likelihood that an explosion of coal-dust will occur. The report that an explosion has occurred in a "rock-dusted" mine immediately conveys to the mind of the alert safety advocate the information that the mine is inadequately rock-dusted or that either dust sampling of the rock-dusted surfaces has not been done or, if done, the mine has not been redusted with sufficient promptness. Rules for Collection of Samples Collection of dust samples is by no means intricate, but a few simple rules must be kept in mind if the results are to be dependable. A sample must represent the true average conditions of the dust in the section or zone in which it is taken, and therefore 'the point at which the sample is to be collected must be selected with care. During an explosion much if not all of the dust on the ribs, roof, timber, and road in the affected region is blown into the air; the sample, therefore, should contain all loose dust and material on: the surfaces to a depth of about 1 inch, if that amount is present. If there is considerable sand locally along the track, care must be taken not to include enough of this material to vitiate the sale and distort the results; however, if the sand is distributed throughout the region being sampled it should be included. Dust should not be collected from recesses in the ribs, such as hitches cut for timber, as the character of the dust in such places is often different from that on the ribs proper. Samples should not be collected at points where the dusting machine has been loaded or at a point where the machine has stopped and discharged for a longer period than at other points on the entry or in the rooms. In short, the sample must represent AVERAGE CONDITIONS, and if there is any doubt as to the character of the dust it is far better to have too much combustible matter than too much incombustible matter in the sample, as it is best to err on the side of safety if it is necessary to err.

Jan 1, 1929

By Howard F. Puariea

This paper is one of a series describing methods and costs of recovering sand and gravel from alluvial deposits in the United States and deals directly with the methods employed by the Portland Gravel Co. in operating a clamshell dredge on the Willamette River near Portland, Oreg., and a pump dredge on the Columbia River near Vancouver, Wash. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local expenditures only and not total production costs. It is recognized that publication of total costs may in some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand operating costs are essential to the technical discussion and study of methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue.

Jan 1, 1932

By W. Wallace, T. Ong, M. Gautam, M. Keane, S. Xing, J. Harrison

"Diesel exhaust soots were assayed in the Ames Salmonella typhimurium histidine reversion assay system using TA 98, the soots being applied as the following preparations: dispersion in dipaimitoyl glycerophosphoryl choline (DPL), dispersion in dipalmitoyl phosphatidylethanolamine (DPP!), and dispersion in dipalmitoyl phosphatidic acid (DPPA) in physiological saline, and in physiological saline without added surfactant. The extracts of soots by dichloromethane / dimethylsulfoxide (DCM/BHSO) were also assayed. Studies were performed both with and without :IQ microsomal activation of the soot preparations. The DPP! and DPPA surfactants were chosen as phospholiridz with two palmitic acid moieties esterified to a glycerol as is the case with DPL, but with hydrophilic groups having different electrophilic characters. The soots, without S9 activation, showed mutegenic activity when extracted in the conventional procedure with DCM/DMSO. The mutagenic activity of soots dispersed in DPL was quantitatively comparable to, and in some cases greater than, the activity expressed by an equal mass of soot extracted by DCM/DMSO. Soots in other surfactantpreparations, DPP! and DPPA, also expressed positive mutagenic activity. Praincubation with S9 microsomal enzyme fraction reduced the activity of solvent extracted soots, and greatly diminished the activity of DPL dispersed soots. Initial sister chromatid exchange (SCE) assays using the Chinese hamster V79 cell line indicated DPL dispersed soot also can cause SCR in mammalian cells. Results thus far suggest that surfactant suspended or ""solubilized"" respirable soot particles could provide a mechanism for transport and expression of mutagens in the lung."

Jan 1, 1989

By Wm. W. Odell

In distributing natural and mixed gas, the industry is each year confronted with the problem of manufacturing gas in increasing amounts as the supply of natural gas becomes more nearly exhausted. The manufactured gas is now used in mixtures with the still available natural product, and will subsequently be used straight as a substitute gas. The gases that might be considered, and are producible by tried and developed processes, include water gas, carbureted water gas, and coal gas. Singularly, these gases can be used in this manner in ordinary appliances only when proportional amounts of them in the mixtures do not vary beyond rather definite limits, unless burner adjustments are made. The limits are defined by the specific gravity, content of inerts, and burning properties of the respective gases. Anticipating a future standard for city gas lower than that of natural gas during the period when considerable natural gas is available, there is justification for considering the possibility of re-forming natural gas and making a product that has substantially the same properties as other gases which can readily be generated. This report gives the results obtained during a series of tests made under a cooperative agreement by the U. S. Bureau of Mines with the Ohio Fuel Gas Co., re-forming natural gas at Toledo, Ohio, in full-scale operation in a water-gas generator having a grate area of 25.1 square feet. ACKNOWLEDGMENTS The Ohio Fuel Gas Co. constructed a special water-gas generator for the tests and provided men and the necessary funds for its operation. Appreciation is expressed for the general spirit of helpful cooperation which was evidenced in the activities of all those who took part in the work. Particular acknowledgment is made of the assistance rendered by C. W. Wallace, manager, and by C. F. Cramer, superintendent, and A. Upp, foreman of the plant.

Jan 1, 1929

By Robert Blickensderfer

Equipment and procedure for the continuous roll bonding of metal strips are described. The reels, mill rolls, and furnace were located within a vacuum chamber capable of operation at a residual gas pressure of 1 x 10-4 to 1 x 10-5 torr. Several metals were successfully clad at rolling temperatures of 930° to 1,050° C in lengths up to 120 ft. The bimetals that were clad included stainless steel to carbon steel, molybdenum and nickel to stainless steel and carbon steel, and titanium to carbon steel. Bend tests of bond integrity are described, and microstructures of the interfaces are presented. The amounts of brittle intermetallic phases formed at the interface are minimized by this cladding method.

Jan 1, 1980

By Donald P. Schlick

This report presents a representative cross section of methods success- fully used to ventilate continuous-miner places as well as various factors that should be considered when selecting auxiliary ventilating equipment. Line brattice can direct fresh air to the active face reasonably well, provided that adequate area for installation is available. Continuous mining equipment, however, often restricts clearances to such an extent that proper installation of line brattice is impossible. Consequently, in many instances face ventilation is inadequate; therefore, many methods of auxiliary ventilation for continuous-mining equipment have been developed and have been discussed in this study.

Jan 1, 1963

By Andrew B. Cecala, Edward D. Thimons

The Bureau of Mines has successfully tested a method to simulate methane (CH~) flows from face areas through the returns of noncoal mines. This technique' involves releasing a small quantity of tracer gas at a working area and sampling for that gas downstream in the re- turn airways. By measuring the dilution of the tracer gas, the dilution of any volume of CH4 released at the face can be calculated. This information is useful in selecting locations for CH4 monitors and in deciding the necessity for permissible equipment in the returns.

Jan 1, 1984

By John R. Shattuck

Preliminary examination of the McCormick chromite property was made by the Federal Geological Survey and the Bureau of Mines during the spring and summer of 1943. In October 1943 an exploratory project was undertaken by the Bureau in cooperation with the Survey and was completed in February 1944.The urgent need during the war for high-grade lump chromite such as produced at the McCormick mine, was one of the pertinent reasons for the project. The McCormick mine is situated about 12 miles southwest of the town of Sonora, in the foothill belt of the Sierra Nevada Mountains, Tuolumne County, Calif. The chromite occurs as irregularly shaped lenses in masses of dunite contained in a steeply dipping, sheared, serpentinized zone of peridotite, near a contact with granodiorite.

Jan 1, 1949

By G. S. Rice

The recommendations of the Bureau of Mines on rock-dusting practices are embodied, except in a few details, in the Recommended American Practice for Rock-Dusting Coal Mines to Prevent Coal-Dust Explosions,5 approved by the. American Engineering Standards Committee,6 December 30, 1925 It is specified that the dust to be used is of a size that all will pass through a sieve having 20 meshes per linear inch and that 50 per cent or more will pass through a sieve having 200 meshes per linear inch.

Jan 1, 1930

By J. B. Newson

This is one of a series of circulars dealing with mining methods, practices, and costs. It describes the method of sinking a shaft 60 inches in diameter with a shot drill, as employed at the Idaho Maryland mine, Grass Valley, Calif. The operation involved a great deal of experimentation in applying the shot-drill method to large bore drilling, overcoming mechanical and other difficulties which developed during sinking, and developing operating technique. Under such circumstances, costs are obviously higher than they would be after the pioneer work has been done, but even so, these actually obtained compare favorably with costs of sinking by more conventional methods. ACKNOWLEDGMENTS The authors are indebted to Mr. Errol McBoyle, president of the Idaho Maryland Mining Co., not only for his cooperation and advice during the sinking of this experimental shaft, but for permission to prepare this article for publication with the inclusion of cost data.

Jan 1, 1936

By Donald P. Schlick

This report presents a representative cross section of methods successfully used to ventilate continuous-miner places as well as various factors that should be considered when selecting auxiliary ventilating equipment. Line brattice can direct fresh air to the active face reasonably well, provided that adequate area for installation is available. Continuous mining equipment, however, often restricts clearances to such an extent that proper installation of line brattice is impossible. Consequently, in many instances face ventilation is inadequate; therefore, many methods of auxiliary ventilation for continuous-mining equipment have been developed and have been discussed in this study.

Jan 1, 1963

By E. D. Gardner

"Introduction Ore from stopes in metal mines is generally dumped or drawn into chutes or raises through which it passes by gravity to the haulage levels. Occasionally, and under some conditions quite frequently, the ore in a chute will wedge or hang and refuse to run. This hanging of the ore may be due to the packing of damp or clayey material, to boulders forming an arch, or to loose lagging or other timber becoming lodged in the chute.In drawing material from a loading chute it is drawn out a car at a time, and the intermittent flow of the material .increases its tendency to hang. When the obstruction in the chute is near or at the loading gate, the chute pullers start the ore by punching it with iron bars inserted through openings in the chute gate. When the obstruction is beyond reach of the bars, other means of starting the ore must be used.In some systems of mining, chutes or ore raises are built with timber as the stope extends upward. Generally, a manway is left alongside of the chutes, and when the ore hangs in a chute usually it can be started by a miner from the manway ladder by pounding on the timbers of the chute or by punching the ore with a bar inserted through small holes in the chute lining. Special methods of starting clogged ore, such as shaking a chain left hanging in the chute, are used at some places.In other systems of mining, ore passes or chutes are run through solid rock and when the ore hangs in one of these passes, either it must be blasted or else started from the top. Sometimes the ore can be started by running water into the top of the chute, but if the water does not start the ore moving, it must be blasted from underneath. This is done by detonating a bundle of cartridges under the obstruction in the chute or raise."

Jan 1, 1927

By F. F. Hintze

In the group of minerals used in making this study, the cyanite is associated with quartz, mica, and feldspar in the schist. The amount of quartz is variable, but it is always an abundant mineral. Both large and small crystals of quartz occur in irregular masses, rarely ever showing crystal outline. Mica Is of the clear and dark varieties, the larger crystals being dark as a rule, and the finer crystals of light color. The present mineralogical composition of the mina is rather variable, as most of the original biotite and muscovite have suffered alteration, and much secondary mica is present as a result of alteration of the original mica and other minerals present, especially the larger cyanite crystals. A large part of the mica now found in the ore is chlorite, with varying amounts of Jefferisite and others, especially sericite. These are in the form of aggregates, or felt-like intergrowths filling the spaces between the quartz, cyanite, and feldspar. The feldspar is plagioclase probably mostly albite. It is white, possesses good cleavage, and is one of the hard brittle minerals of the rock. It alters to kaolin, and sericite, and more or less of these alteration minerals are present within the feldspar crystals but not separated from them. The cyanite is of two varieties, distinguished by their colors as blue and white cyanite. The blue color varies in intensity, being a pronounced blue in some crystals and paler in shade in others. Some crystals have been seen which posses the blue color in one-half of their mass and are pure white or clear in the other half. The purity of the cyanite is probably not affected by the color, but it is difficult to detect the white cyanite in the ore by macroscopic examination, so that great care has to be exercised in the selection of the ore in the field. Of the above minerals, cyanite is the heaviest, having a specific gravity of 3.6; none of the others approach it in specific gravity. The usual as opiates of cyanite in the mica schists are garnet, magnetite, and tourmaline, but these have not been noted in the group of minerals treated, and their absence is a point of great value in favor of this ore, as they possess high specific gravities and interfere in separation processes, and if not separated they are detrimental because of their easily fusible character. Small amounts of apatite and titanite have been noted, but not enough to cause trouble.

Jan 1, 1931

By Thomas M. Barczak

This report describes a study that examined load transfer mechanics in longwall shield supports as part of the Bureau of Mines research program to optimize support design and utilization. The objectives of this study were to determine the contribution of the leg cylinders and the caving shield-lemniscate assembly towards full shield vertical and hor-izontal load resistance capability and to determine how the interaction of these members affect overall shield response. Load-displacement characteristics of the leg cylinders and the caving shield-lemniscate assembly, independent of the full shield, were evaluated from controlled displacement tests in the Bureau's mine roof simulator and responses were compared with full shield responses to identify load transfer mechanics. It is concluded from this research that the participation of the caving shield-lemniscate assembly significantly affects the response of the shield support. It is likely that the caving shield-lemniscate assembly is not participating fully in current shield designs because of translational freedom in the numerous pin joints. It is also concluded that the shield will respond differently to different boundary condi-tions resulting from interaction with the strata. This report describes load transfer mechanics of shield supports and the implication of these research findings on shield design and utilization.

Jan 1, 1988

By A. B. Needham

The Great Eastern nickel deposit is located in the western foothills of the Virgin Mountains in the Copper King or Bunkerville district situated in the southeastern part of Clark County, Nev. It is covered by a group of eight claims that can be reached by turning south from U. S. Highway 91 at Riverside, Nev., and driving about 12.6 miles southeast over a winding mountain road, which rises from about 3,000 feet to 4,000 feet in elevation. The climate is dry, with only a small amount of rainfall throughout the year. The temperature ranges from hot during the summer to short periods of freezing weather during the winter months. The vegetation is of the desert variety, and no timber is available for mining. Water for mining purposes would have to be pumped from lower areas. A granitoid gneiss comprises the largest part of the rock outcrops. It has a steeply dipping foliation that strikes about N. 75° E. The gneiss was intruded by basic dikes, which in turn were intruded by pegmatite dikes. The ore occurs as lenticular bodies formed by the convergence of several pegmatite dikes within the main dike. The principal sulfide minerals are pyrite, pyrrhotite, and chalcopyrite, which contain a small amount of nickel. Late in the year of 1939, the Bureau of Mines undertook an exploration project on the Great Eastern property to extend or delimit the known mineralization. Underground work, consisting of 590 feet of drifting and crosscutting, was completed in September 1940, and 1,091 feet of diamond, drilling for downward extension of an ore body in the Lower edit, which was completed in February 1941.

Jan 1, 1950

By A. W. Ambrose

"Records of individual wells form the basis for the successful operation of any company engaged in the production of petroleum. The expense attached to the compilation of records is negligible in comparison with the benefits resulting from their use. There a company has not a complete system of records, immediate attention should be given to the preparation of forms upon which to collect data, and, to the collection of data for these forms. The records needed vary with each district, but for each field a set should be adopted that will best meet the needs of each property. Practically all operators, and particularly all successful operators, agree on the necessity of good records, shopping what the wells have done, are doing, and may be expected to do in the future. Any operator realizes the value of records of sales of oil and should place almost equal emphasis on the records of well logs and histories showing the east and present performances of wells. Indeed, trustworthy records are absolutely necessary for the proper operation of any oil or gas property.Complete records should be kept on each well from the time the location and elevation are determined until the well is abandoned, and the engineer should review old records often enough to be familiar with the past performance of the various wells and with the conditions that affect production. Some of the forms that may be prepared are:--"

Mar 1, 1920

By R. V. Ramani, R. Bhaskar

"An airborne dust cloud is an ensemble of particles of varied size, density, shape and states of aggregation. An understanding and quantifying of the dispersion and deposition of the dust generated in mines is essential to the development of measures for reducing worker exposure to dust. In coal mining, the major portion of the dust is generated during the cutting of coal using a shearer or a continuous miner.The major phenomenon affecting ambient concentration is the deposition of dust. Particle deposition may take place due to the effect of gravitational, inertial, electrostatic, and thermal forces, and mechanisms such as Brownian and eddy diffusion and inertial impaction, The three major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. The mechanisms determining particle deposition are size depend,From a review of the literature, there appears to be a knowledge gap in the understanding of the deposition phenomena in mine airways. In order to obtain a better understanding of the deposition of dust for various particle sizes, and to develop a set of data for evaluating predictive mathematical models for dust-flow in mines, a series of dust flow experiments was performed under controlled conditions in mine airways. It appears that the deposition data generally follow the theoretical behavior of dust based on the combined effect of diffusional and gravitational deposition. In this paper, the findings of the study on the deposition of dust in mine airways and its dependence on size, velocity and concentration are discussed. A set of deposition equations that could be used to determine the approximate deposition at various points in a mine airway are presented.The major factor affecting ambient dust concentration in mine airways is the deposition of dust. Particle deposition may take place due to the effect of gravitational, inertial, electrostatic, and thermal forces, and mechanisms such as Brownian diffusion, eddy diffusion and inertial impaction. The major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. Inertial impaction is significant only during changes in direction, but the change in direction of flow with resultant powerful eddies may cause increased re-entrainment of the particles, thus having a compensating effect. While the literature in aerosol sciences contain several references on deposition, most studies were done in small diameter tubes for diffusional deposition (Liu and Agarwal, 1974). The deposition data from small diameter, short tube experiments may not be applicable to studying deposition in mine airways that have large areas and extend several hundred meters. Further, the change in concentration along the length of a mine airway may significantly affect the deposition, an aspect that may not be easily determined in short tubes in laboratory experiments."

Mar 1, 1992