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By N. F. LeJeune, Earl C. Lane

This is the third of a series of reports on a survey of petroleum prod- ucts manufactured on the Pacific Coast from California crude oils. California crudes differ in many characteristics from the petroleum produced in the other parts of the United States, and the claim has been made that some of the present Federal Specifications for petroleum products tend to discriminate against Cali- fomia products. The purposes of the present survey are to determine what par- ticular specification requirements Califomia petroleum products characteristical ly fail to meet, how widely the products deviate from these requirements, and if possible to show whether the fault lies with the specifications or the products, or along what lines investigation to determine this question should proceed. The first report of the series gave the physical and chemical properties of the samples of gasoline and mineral spirits. A second report**, gave the physical and chemical properties of samples of lubricating oils. The present report deals entirely with burning and fuel oils. The refin ing companies have continued their very cordial and helpful cooperation. Seven samples of kerosene, four samples of Diesel fuel and eight samples of fuel oil were obtained. The methods of analysis used are those adopted by the Interdepartmental Petroleum Specifications Committee, published by the Bureau of Mines in Technical Paper No. 323. The specifications used for corparison are those officially adopted by the Federal Specifications Board for the use of the various Depart- ments and Independent Establishments of the Government, effective February 3, 1923, and published by the Bureau of Mines in Technical Paper No. 323, Part 1. Specific gravity, degrees A.P.I., viscosity and other special tests al- though not required by the specifications have been given for comparison. All temperatures are recorded in degrees Fahrenheit. Tables have been prepared giving data on physical and chemical propertios of the individual samples. Before each table the classification and specifica- tions for the particular class of oil considered in the table are given. Follow- ing each table, brief notes show wherein samples deviate from specification re- quirements.

Aug 1, 1923

By E. J. Gleim

Contact with trolley wire in the mines of the United States has taken a considerable toll of life throughout the years that trolley locomotives have been employed as a means of' transportation. A study3/ of the records over a 15-year period for one State alone showed that, of 98 fatalities resulting from contacts with electrical circuits and equipment, 75 were caused by direct or indirect contact with unguarded trolley wire in coal mines. The law relating to guarding trolley wires in the mines of this particular State, as amended in 1935, reads in part as follows: "All trolley wires carrying 220 volts or more, and less than six feet six inches above top of rail, must be guarded at all points under which men and animals are required to pass***,'" The natural conclusion to be drawn from such records is that lack' of guards or shields must be held responsible for these fatalities. As a preventive measure, it has been advocated that every foot of trolley wire in mines should be guarded. Although some such drastic steps may appear to be amply justified, closer examination of the records nor this and other coal-mining States shows that absence of guards is not entirely responsible; but rather that other factors, such as carelessness and neglect it the observance of certain well-established simple rules concerning installation and location of trolley wires, also are responsible. In other words, if trolley wire is installed carelessly and its maintenance is neglected, it should not be expected that the mere installation of guards will overcome such carelessness and neglect. This publication discusses Various types of guards that have been used in Coal and metal mines of this country, together with related steps bearing upon the problem of 'preventing shock and fatalities from contacts with trolley wire. The material herein contained is taken largely from Information Circular 6577,4/ now out of print, and has been revised to include some types of guards that have been used in metal mines, together with a discussion of guard materials not covered in that publication.

Jan 1, 1945

By John M. Dower, Ralph W. Plummer, Terrence J. Stobbe, Hyunwook Kim

"The relationship between exposure to coal mine dust and the development of various respiratory diseases is well recognized. The cause of these diseases however. Is still uncertain. To study this cause-effect relationship, It Is necessary to characterize the coal mine dust In terms of the quantity of dust present and mineral content of the dust. Dust samples were collected using a Portable Continuous Aerosol Monitor (PCAM) and 4-stage cassette Impactors at various locations in an upper Freeport seam coal mine In West Virginia. The samples were analyzed using an X-ray microdiffraction film technique and energy dispersive scanning electron microscopy. This paper presents the results of the first phase of this characterization work which Includes determining the size distribution of the dust and the mineral content of the size intervals.IntroductionDiseases associated with dusts in coal mine environments continue to afflict miners in today's modem mines. These diseases still persist because, as Olishifski points out an employee rarely experiences exposures to a single environmental stress but rather to an Intricate Interplay of multiple stresses.(1) In the case of coal mining the multiple stresses are varying sizes of dust particles originating from coal imbedded minerals. Immediate roof strata bottom strata. Incombustible rock and the coal itself. The site of this Intricate Interplay Is the miner's lungs and the resulting diseases are a function of the composite dust exposures.The proper study of coal mine dust toxicity requires that the dusts used replicate existing coal and mineral dust compositions in their relevant size fractions. The purpose of this project is to develop the size and mineral content data necessary to support this ongoing toxicological effort.Existing coal mining standards and regulations also address total and respirable dust exposures. These dust terms refer to both the quality and quantity of the dust segment in the mine atmosphere. Dust quality addresses its coal and mineral content. whereas dust quantity Is described by mass per unit volume (mg/m3) The comprehensive characterization of coal mine dust exposures will enable revision of these standards and regulations to address the specific minerals and size fractions found to be toxic to human lung tissue."

Mar 1, 1989

This Technical Memorandum Report is a collection of three working memoranda, prepared during the course of our work for the Bureau of Mines and bound together for convenient reference. These working memoranda present preliminary performance estimates, for baseband voice and narrow- band through-the-earth electromagnetic communications systems of principal interest to the Bureau, for operational/emergency mine communications. The calculations were prepared to obtain early indications of the feasibility and governing parameters of such communications systems. They are based on limited, but pertinent, coal mine electromagnetic noise data acquired to-date by Bureau of Mines contractors; and of theoretical signal-attenuation characteristics for two transmitter antenna types of present interest to the Bureau. The memoranda examine the cases of baseband voice and narrowband communications for uplink and downlink transmissions, for frequencies up to 3kHz. Downlink transmissions are via a horizontal wire antenna, up- link transmissions via a vertical-axis loop antenna, for typical mine depths of 300, 600, and 1000 feet. Representative coal-mine overburden conductivities of 10-2 mhos/meter (moderate and common) and 10-1 mhos/meter (high) were used; for voice and narrowband, 10-1 for narrowband only. Examples of high, moderate, and low; surface and subsurface; harmonic and broadband-impulsive noise conditions were taken from NBS and Westinghouse (WGL) mine noise data, together with examples of high- and low levels of ELF atmospheric noise taken from M.I.T. Lincoln Laboratory data. These feasibility calculations are not intended to serve as definitive and complete treatments, but as a starting point: to establish first-order estimates of the magnitude and variability of transmitter power requirements under different noise, overburden conductivity, and mine depth conditions; to identify relationships, conditions, or frequencies that are likely to limit or enhance system performance; to reveal items requiring further investigation and data still required; and to suggest practical methods for optimizing system performance. These objectives were met by the calculations. Simple experiments to support these calculations can and should be carried out; together with more detailed investigations of specific modulation, coding, noise-suppression, voice-compression and signal-conditioning techniques, aimed at producing through-the-earth operational/emergency mine-communication systems that are not only effective, but practical and economically sound.

Jan 3, 1972

Although the technology involved in removing material from below the earth's surface has a long history, communication systems in underground workings are relatively new to the industry. Communication equipment did not begin appearing in underground mines until the early 1900's. Figure 1-1 shows a miner using a Western Electric standard telephone set for underground mines in 1913. These early phones were essentially the same as those used aboveground, except that they were enclosed in cast-iron boxes as protection against moisture, acid fumes, and gases. In the 1950's, the Chesapeake and Potomac Telephone Co. of West Virginia introduced a telephone set for use in explosive atmospheres that was designed around the philosophy of explosion containment. To contain an explosion within the telephone set required a 39-pound casing, which greatly limited portability. [ ] Both of these telephone sets required "pipe" or conduit, not a very practical item for a 100-squaremile coal mine. A common thread prevalent in the first 40 years of design and development is that the primary effort was placed on the telephone set. In the early 19701s, as work began on the design of modern communication systems for use in underground mine environments, the following requirements were established: 1. Must meet intrinsic safety standards .--This applies not only to coal mines, but to other explosive environments. 2. Must be compatible with the environment.--The system must with- stand dust, moisture, and corrosive conditions. 3. Must be rugged in structure.-- The system must withstand maintenance by 10-inch pliers and 4-pound hammers, as well as impact from a falling piece of roof. 4. Must be size-flexible.--Whatever is built must be sized for the small operator as well as the large companies. 5. Must be a total system in design.--The system must be intrinsically safe, including cable, power supply, and station set. 6. Must work with present telephone system.--The system should be compatible with aboveground communications already in place; it should not be the single cause of change in aboveground communications. 7. Value-added pricing.--The system should be reasonably priced so that savings created by its introduction will more than offset the installation cost.

Jan 1, 1984

Develop an environmentally feasible method of mining shallow oil sands without removing overburden. Approach Oil sands are extracted through a single borehole by cutting into the sands around the borehole with a high pressure water jet, and pumping the resulting slurry to the surface. Although oil can be extracted from shallow fields by open-pit mining methods, this type of mining may create significant environmental impacts, including; (1) disruption of the surface, (2) accumulation of waste rock piles, (3) accumulation of tailings, (4) damage to the ground water quality, and (5) surface water pollution. The borehole mining system developed and successfully field tested by the Bureau of Mines offers a method for extracting oil from oil sand with minimal disturbance to environmental quality. (For examples of other applications of borehole mining, see Technology News Nos. 95, 63 56, and 48.) How It Works Prior to the start of mining operations, baseline conditions for ground subsidence and ground water quality are established at the test site so that the degree of subsidence and changes in ground water quality can later be determined. Oil sands mining is conducted using the Bureau of Mines borehole mining system. The borehole mining tool consists of a 12-inch-diameter pipe string and accessories capped with a three passage swivel terminated with a mining section. The mining section has an auger at the bottom. Four slurry inlet holes and an eductor are located above the auger, and a single cutting nozzle is located near the top of the mining section. The tool generates a high velocity water jet that erodes and slurrifies ores. The slurry is drawn into the inlet of the eductor which lifts the slurry to the surface where it is deposited into a slurry discharge sump. To detect evidence of subsidence, surveys of the land surface are made at regular intervals during, and until 30 days after, the termination of the mining operations. Samples of ground water from the borehole and two adjacent monitor holes are taken on alternate days during the mining operations, and are later analyzed to determine if any ground water contamination has occurred.

Jan 1, 1981

By A. C. Fieldner

It is estimated that 6,202,235,000 gallons .of- gasoline was produced during the year 1922. The crude light oil- output Burin- the same year is estimated at 111,000,000 gallons, or 1.8 per cent of the gasoline production. In fact, if all the coal mined were coked in by-product ovens, and the light oil recovered therefrom, this product would amount to only 15 to 20 per cent of the quantity of the petroleum gasoline now produced annually. It is obvious therefore, from these figures that the light oils by present coking processes can not assume great importance as a gasoline substitute in a national sense. However, the use of light oil as a motor fuel is of real importance in districts adjacent to by-product coking operations from which a reasonable proportion of the local motor fuel supply may be derived. The certainty of diminution of petroleum resources in the relatively near future demands the utmost utilization of gasoline substitutes from the distillation of coal as well as other sources. Motor benzol is a by-product from the destructive distillation of coal. From 11/2 to 3 gallons of refined motor benzol is obtained per ton of coal carbonized. The light oil vapors are extracted from the by-product coke-oven gas by passing it upward through a series of towers in which these vapors are absorbed in a descending current of "wash" oil (petroleum distillate). The light, oil is recovered from this wash oil by distillation with live steam, the resulting crude light oil consisting of a mixture of benzol, toluol, xylol, solvent naphtha, and a small amount of other substances (unsaturated hydro-carbons, carbon disulphide, and other sulphur compounds, phenols and pyridines) is then transferred to an intermittent still and fractionated into crude motor benzol, which includes the toluol and a part of the xylol or light solvent naphtha. The crude, motor benzol is yellow in color, contains sulphur compounds which corrode copper and brass, and also contains unsaturated bodies which oxidize and polymerize on standing, producing sediment and forming gummy deposits highly objectionable when the benzol is used in motors. These objectionable

Jan 1, 1923

By C. Travis Anderson

"A recent critical study by Ralston3 of the iron system points out the importance of and necessity for work upon the preparation of ferrous oxide. Not only are ferrous oxide samples desired for determination of the important physical and chemical properties, such as specific heats and heats of formation, bat also information on the stability and behavior of this material is of considerable technical importance. Related. problems where the properties of Fe0 are important have to do with desulphurization of iron, the formation and occurrence of magnetite in copper smelter slags, and sulphur elimination in copperFerrous oxide also has valuable catalytic properties, as is demonstrated in nitrogen fixation.Pure ferrous oxide has never been prepared in quantities large enough to furnish adequate physical and chemical data on its properties. Only two or three experiments4 have produced a fraction of a gram in a state approximating purity and have collected evidence that has been sufficient proof of their having done so. Ferrous oxide is stable only above about 570°C., and below that splits into magnetite and iron according to the reactionUp to about 1920, those who had endeavored to prepare FeO made no provision for rapid chilling, so that although their product. may have had the proper iron oxygen ratio for FeO, in reality it-probably did not consist of pure FeO. The above reaction is reversible; above 570oC. magnetite and iron are supposed to recombine almost completely, and if so, should constitute a direct and easy method of preparation. The data, however, were somewhat conflicting, and the extent to which the reaction goes in either direction needed checking. Preliminary experiments on the interaction of molten Fe304 with solid Fe gave Fe0 of about 85 per cent purity, corresponding to. the approximate purity obtained by some previous investigators. The present work is concerned chiefly with the results cf repeated interaction between partly reduced magnetite and iron, and the calculations which may be made from such results. Repeated treatments are necessary, because molten impure ferrous oxide and iron can not be kept in contact for more than short periods of time."

Oct 1, 1928

By G. Nuñez, M. A. Pathak, C. F. Stanley

"Holographic interferometry is a non-destructive technique to detect small deformations1 of an object. It is a whole-field technique· with an accuracy of a few microns. An adaptation of holographic interferometry is time-averaged holographic interferometry which is particularly useful in detecting small vibration amplitudes of an object under investigation. Its application to biological tissue is especially difficult due to the combination of (a) the high sensitivity of the technique, and (b) the tendency of these objects to deform excessively, or move during the testing period. (This is also compounded by the changing moisture content of the tissue surface.)Ideally, a pulsed laser and fast-acting thermoplastic film camera could be chosen to overcome these difficulties, but the total equipment cost could exceed $75,000. In this paper we describe our relatively economical method to apply time· averaged holographic interferometry to an excised animal lung, utilizing holographic plates and a mechanically-shuttered continuous-wave Argon laser.EXPERIMENTAL METHODThe schematic of the experimental setup is shown in Fig. 1. The holographic equipment, including the laser, is fixed on a 3 ft x 6 ft x 4 in. honeycomb holographic table. This table is functionally similar to one described by Mark and Horsch2 which can be constructed for about one thousand dollars. The holographic table itself rests on six inner tubes to absorb floor vibrations. All unnecessary vibrations must be reduced to preserve the quality of the holograms. A laser beam from a 0.5-watt continuous-wave Argon laser is split by a circular variable beamsplitter (Newport Corporation Model 50GOOAV.1) into two beams, i.e., an object beam and a reference beam. The object beam is again split into two beams of equal intensity by a 50150 beamsplitter (Newport ·Corporation Model BS.1). These beams are optically filtered and expanded by spatial filters (Newport Corporation Model 910) to cover as much area of the object as possible. Soft biological tissues exhibit low reflectives, resulting in a relatively high reference to object beam ratio of roughly 5 : 1 at the holographic plate."

Jan 1, 1989

By R. V. Ramani

"Exposure to respirable contaminants in mine atmospheres has long posed a serious hazard to miners. The control of these hazards, some of which can have sudden and catastrophic effects and some others, slow and long enduring consequences, has been a major concern for labor, management and government alike. This concern has manifested itself in four primary mechanisms of control -- (1) regulatory control through minimum standard setting by the passage of mine health and safety laws, (2) engineering control through design and operation of 'mines according to the best recommended practices, (3) medical control through periodic physical examinations, wearing personal protection devices, etc., and (4) legal and social control through workmen's compensation laws for occupation related health deterioration:-The respirable contaminants in mine atmo¬spheres are toxic and explosive gases, toxic and explosive dusts, diesel exhaust particu¬lates, radon progeny, etc. Perhaps the most important of all these and the most widely occurring in mine atmospheres is respirable dust, an inevitable product of fragmentation, a unit operation fundamental to all mining operations. In fact; the-most serious health hazard for workers in the mining and minerals processing industries is still the exposure to respirable dust, and solutions to the problem of respirable dust disease remain to be found.The 1969 Coal Mine Health and Safety Act and its provisions for the respirable dust standards in underground coal mines are briefly reviewed. An overview of the research accomplishments in meeting the standards is presented. The current state of knowledge on the effectiveness of the standards and the new and emerging problems are discussed. A brief summary of the research programs of the Generic Technology Center on Respirable Dust is presented.In general, underground mines are becoming increasingly safe. The mine atmospheric environment is definitely improving * Professor and Head, Department of Mineral Engineering,-The Pennsylvania State University, University Park, PA for the better. Significant progress has been made in lowering the dust levels in mines. It is generally agreed that mines are less dusty today than they were a decade ago. However, as long as the risks of occupation-related diseases are not completely eliminated, vigilance can hardly be relaxed, and the search for engineering solutions must be intensified."

Jan 1, 1988

By Oliver Bowles

"The introduction into mines, quarries and manufacturing plants of machines and tools operated by compressed air has revolutionized methods of operation to an extent comparable only with that occasioned by the invention of explosives and the utilization of electricity. The use of compressed air in pneumatic tools, in rock drills, and for the operation of pumps and other machinery is well known to most miners and quarrymen, but its application as a substitute for explosives for breaking rock in a few granite quarries has received little publicity.In the region of Lithonia, a few miles from Atlanta, Georgia, is a dome of massive granite used widely for building stone and for paving blocks. The most remarkable structural feature of the granite is the absence of joints and sheeting planes. The term ""joints"" is applied to open fractures that commonly occur in rocks, usually vertical in direction or nearly so, and spaced from a few inches to several feet apart. On the Lithonia granite outcrop, however, one may walk over the bare rock surface for hundreds of feet without finding any indications of a joint, ""Sheeting planes"" are open fractures at various levels, approximately parallel with the rock surface. The presence of such planes when spaced several feet apart greatly facilitates quarrying, and where absent, as at Lithonia, the necessary fractures must be made artificially.The forcing of artificial sheeting planes is accomplished as follows: Two holes of about 3-inch diameter arc drilled close together and to a depth of about 8 feet. Two men work at these holes all summer, and sometimes part of a second summer. A very small charge of black blasting powder, not more than a spoonful, is placed in each hole, tamped with clay, and the charges are fired simultaneously with an electric battery. This starts a small fracture running outward from the bottoms of the holes. There is in most granites one direction of easy splitting known among quarrymen as the ""rift"", and as the rift direction in the Lithonia granite is horizontal the fracture follows a horizontal plane,"

Aug 1, 1920

By Jeanne A. Zimmer, Charles D. Taylor, Edward D. Thimons

On a continuous miner coal face methane concentrations are affected by the quantity of fresh intake air reaching the face. When mining the box cut on a 12.2-m (40-ft) two-pass extended cut face, the continuous miner is always at the point of deepest penetration, and operation of the machine-mounted dust scrubber and water spray system improve the flow of fresh air to the end of the box cut. However, when the continuous miner leaves the box cut to begin cutting the 40-ft slab, little is known about how much ventilation air reaches the end of the box cut. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health conducted a full-scale study to answer this question. Tests were run to determine how much ventilation air reaches the end of the box cut with the continuous miner at three locations in the 40-fttwo-pass extended cut mining sequence; at the end of the 40-ft box cut, at the start of the 40-ft slab cut, and 6.1 m (20 ft) into the slab cut. During these tests, methane gas was uniformly released at the end of the 40-ft box cut. Methane concentrations measured0.3 m (1 ft) from the roof and face of the box cut were used to estimate face airflow quantities. Fresh air flow rates of 1.89and 4.72 m/sec (4,000 and 10.000 cfm), scrubber flow rates of 0, 4,000 and 10,000 cfm, water spray pressures of 0 and3827 kPa (0 and 120 psi), and a blowing curtain setback position of 15.2m (50 ft) were used during these tests. To improve ventilation to the end of the 40-ft box cut when the continuous miner was starting the 40-ft slab cut and 20 ft into the slab cut, the blowing curtain was advanced from its 50-ft setback to locations 40-ft and then 8.5 m (28 ft) from the face. KEYWORDS: Face ventilation, Extended cut, Methane, Box cut, Continuous miner, Scrubber

By Kihong Park

A hygroscopicity tandem differential mobility analyzer (HTDMA) technique is used to determine size-effect of nanoparticles (NaCl, (NH4)2 SO4, KCl, NH4NO3, MgCl2,CaCl2) on their hygro­scopic properties (deliquescence relative humidity (DRH) and hygroscopic growth factor (GF)). The HTDMA system uses a combination of two nano DMAs and two regular DMAs to measure particle size change in a wide dynamic particle size range. Particles are subsequently analyzed with a transmission electron microscopy to investigate the potential effect of particle structure or morphology on the hygroscopic properties. We found that structural properties of NaCl and (NH4)2SO4 particles also play an important role in determination of the DRH and GF and are more pronounced at smaller diameters. Data show that the DRH of NaCl nanoparticles increased from *75% up to *83% RH at 8 nm and that their GF decreased with decreasing size. The extent to which the GF of NaCl nanoparticles decreased with decreasing size was greater than theoretically predicted with the Kelvin correction. The GF of furnace-generated NaCl nano­particles that have pores and aggregate shape was found to be smaller than that of atomizer-generated particles that are close to perfectly cubic. For the case of atomizer-generated (NH4)2SO4 nanoparticles, we observed no signi?cant size-effect on their DRH, and the measured GF agreed well with predicted values using the Kelvin correction. For furnace-generated (NH4)2SO4 nanoparticles, a gradual growth at moder­ate RH without noticeable deliquescence behavior occurred. Their TEM images showed that contrary to atomizer-generated (NH4)2SO4 nanoparticles the fur­nace-generated (NH4)2SO4 nanoparticles are not perfectly spherical and are often aggregates having pores and holes, which may favor holding residual water even in the dried condition. For atomizer-generated KCl, MgCl2, and CaCl2 nanoparticles, we observed no signi?cant size-effects on their DRH and GF for the mobility size as small as 20 nm.

Jan 1, 2008

By T. H. Ueng, S. D. Thompson, Y. J. Wang

"INTRODUCTION There is considerable interest among mining companies and government agencies in finding new ways to better control the generation and dispersion of respirable coal dust. Mine face ventilation generally has been considered the most effective tool for lowering the concentrations of respirable dust. Unfortunately, only a limited amount of research has been undertaken to determine the relationships between the various face ventilation parameters and the dust dispersion patterns. If these relationships are better understood, more efficient ways of controlling dust generation and dispersion may be evident. A practical and economical way to gain more in-depth understanding of these relationships is through scale model studies. Past research (1, 2, 3) has substantiated that scale models can be successfully used in studying ventilation parameters provided that geometric, kinematic, and dynamic similitues are maintained.To better understand face ventilation and dust dispersion, a 1/5 scale model of a room and pillar mine face was constructed. This model was then used to conduct experimental investigation on two ventilation parameters. The parameters which were examined included the line brattice distance from the face and the air quantity. The values of these parameters were varied in numerous experiments so that their effects on dust dispersion could be measured.The experiments of this study were unique in two ways. First, two different substances were used to simulate the respirable coal dust. Experiments were conducted with a tracer gas (methane) serving as the dust simulation substance. They were then repeated with an actual dust (Arizona Road Dust) replacing methane as the dust simulating substance. In previous scale model studies, the dust simulation substance has been limited to a tracer gas such as methane. The validity of using a tracer gas to simulate dust is not clearly known yet. The other unique thing about these experiments was the number of points measured for methane (or dust) concentration. Twenty five points in a grid arrangement were measured during each experiment of this study. The number of points measured for concentration in other studies has generally been very small (often 2 to 4). It is difficult to obtain an accurate assessment of how the ventilation parameters are effecting dust dispersion when only 2 to 4 points are measured."

Mar 1, 1989

"A coordinated, integrated research effort aimed at studying the scientific, engineering and medical aspects of the respirable dust problem is underway in the areas of dust generation, dust dispersion and dilution, dust characterization, interaction of dust and lungs, and relationship of seam characteristics to dust generation and mobility. (FIGURE 24) The Center's research program explores these concerns with the objective of refining existing strategies and developing new respirable dust control techniques that are consistent with the dust-lung interaction processes that lead to mine worker disability. The fundamental aspects of this work are applicable to the control of respirable dust problems in both hard rock mines and coal mines and to other dusts such as diesel-generated.Research projects in the Generic Mineral Technology Center for Respirable Dust have effected several improved methods for the preparation and characterization of the dusts needed by these projects. Superior procedures for generating ""standard"" dust samples have been developed and are in regular use in the laboratory. Questions raised during the course of some projects regarding ""stale"" versus ""fresh"" dust have led to the development of sampling techniques where the dust is directly collected in a surfactant. MSHA and CANMET have requested and received information on Center generated software. An equipment manufacturer, TSI, Inc., requesting input on modifying the inlet of an aerosol sampler has been assisted as a result of research that was conducted at the University of Minnesota.The objectives, scope and progress of all the research projects in the Center, in the form of abstracts and reports, have been detailed in Volume 1 of this series. Research papers written by the principle investigators and resulting from the findings of projects (FIGURE 25) and which are funded by U.S. Bureau of Mines grant number G1135142 have been published in Volumes 3 through 6 and Volume 8 of this series. Volume 2 relates the cooperation and interaction of the U.S. Bureau of Mines and the Generic Mineral Technology Center for Respirable Dust in research on the problem of respirable dust in the mineral industries."

Aug 31, 1989

By G. E. McElroy, D. Harrington

The use of shall electrically- driven fans , in conjunction with air- pipe of various diameters is becoming of increasing importance for the ventilation of working places in metal mines through which the general ventilating currents can not be coursed . It will probably continue to increase in importance since the concept that air motion is the most important factor in maintaining comfort in hot ( above 80° F . ) working places is more generally accepted , and as the inefficiency and greater expense of attempting to ventilate such places with compressed air is recognized . Managers of large properties can afford to experiment with fan- pipe installations until types are found that meet their conditions , but managers of shall properties , unless forced to it by extreme conditions , prefer to wait until they can obtain data sufficient to guarantee at least a measure of success from such installations . At present , such data , even in part , are available to only a few (mainly fan manufacturer's representatives , consulting ventilation engineers , and ventilatin engineers employed by large companies ) , and important recent developments are mostly of a confidential nature . One large metal - mining company cooperated with a fan manufacturer in some extensive experimental work on small blowers and found that instead of using stock fans , considerable power economy could be effected and equal quantities of air delivered by use of or 2/3 width fans with small motors rather than using stock fans and larger motors ; it was also found advisable to adopt certain sizes of tubing for certain lengths of run . In fact , many important facts were ascertained in this study , and it is now promised that they will soon be given to the public . It is true that a certain amount of data on industrial installations are available , but such data are only in part applicable to metal -mine conditions , because , until recently , little attention has been given to ventilation in metalmines , and the conditions encountered usually require a greater length of pipe , a more temporary type of construction , and closer attention to temperature control than the ordinary run of industrial installations demands ..

Feb 1, 1922

By George H. Ashley

Character The bituminous coals of Pennsylvania range from low volatile to high volatile, but are all low moisture coals The coals are of three types caking of coking, noncaking or splint, and cannel The percentage of volatile matter in all kinds changes from low at the east to high at the west This change is thought to be due to the pies sure and folding to which the coals along with the other rocks have been subjected In the Broad Top field, and in Somerset, Cambric, Clearfield, Centre, and other counties to the northeast, most coals contain from 3 to 5 times as much fixed carbon as volatile matter, the fixed carbon ranging from 67 to 75 per cent, and the volatile mattes from 16 to 24 per cent These coals are classed as lovol coals In the line of counties just west of those listed the coals are of the medium volatile class (midvols) This includes the famous Connellsville coking coal Still farther west, covering most of Washing ton and Westmoreland counties, and the counties to the north of them are high volatile coals of gas coals (hivols) This is discussed in Part I on the geology of the coals of Pennsylvania, where is given in isocaib map Cannel coals ale found in many par is of the bituminous coal field of Pennsylvania, but in particular in Beaver Butler, Armstrong, Indiana, and Clear field counties The cannels of Beaver and Butler. counties are typical high volatile cannels, many of which have been used in times past for oil distillation The cannels of Armstrong and Indiana counties are medium volatile cannels, and while main taming the physical character of cannels, have no more volatile neat ten than the coals around them The cannels of Clearfield County tie low volatile Splint coals of noncakmg coals are not abundant in Pennsylvania. The Sharon coal, formerly mined in Mercer County, was a noncaking or splint or block coal, and was formerly used in the raw state in non smelting Uses STEAM COAL Practically all of the coals of Pennsylvania are steam coals, though many coals in the Commonwealth, because of high ash, are not good steam coals The coal of the Pittsburgh district has long been famous

Jan 1, 1928

"Health standards in the U.S. are among the highest in the world. Achieving these standards have often had an impact on productivity, slowing output, and raising prices to levels that make it difficult to compete with many foreign industries. The answer to many of these problems lies in the development of new and advanced control techniques. This overview has identified some of the major respirable dust technological hurdles that have been overcome, and provided some insight into current and future approaches underway to remove these obstacles and to provide the United States with the most advanced state-of-the-art mining industry in the world from a respirable dust standpoint. The necessary developmental research is costly and time-consuming. The long-term, high-risk aspects of this effort are being addressed by the Bureau and the Generic Center on Respirable Dust, with support by industry. This should be recognized as one of the principal agents through which the great mineral potential of this Nation can be realized, and our international status as a mining power be assured without compromising the health and welfare of those who ensure it.The problem of more stringent dust standards will continue to grow. To date, approximately 40 pct of the coal mining industry has been placed on more stringent dust standards due to quartz. Control techniques must be improved if mandated levels are to be met. As longwall production increases, dust levels will also increase. In light of the industry trend toward longwall mining, if no new control technology is available, the Federal dust standard will act as a constraint on future output per hour. The Bureau has recently completed a survey of 18 coal preparation plants; 50 pct of these operate at dust levels which exceed 2.0 mg/m3; future work will be directed toward solutions in this area. The 2.0 mg standard for respirable dust is for dust particles which are below 10 pm in diameter. Recent studies have shown that dust in the range between 10 and 25 pm can cause obstructive airway disease. The Bureau is currently determining the extent of exposure to dust in this size range from various mining operations."

Nov 1, 1988

By V. A. Marple, K. L. Rubow

"In our laboratory several impactors have been developed in the past which have penetration characteristics that approximate that of the ACGIH or the British MRC respirable curves. In these impactors the large nonrespirable particles are collected on an impaction plate of a multiple round nozzle stage where the nozzles are of different diameters. The principle for designing a respirable cut impactor is quite simple in that the respirable curve is divided into two or more segments and the nozzles are designed with the correct diameters and number of nozzles to have collection characteristics with 50% cutpoints at the center of each segment. The particles not collected on the impaction plates are then collected upon a filter. These particles represent the respirable fraction of the aerosol. Therefore the respirable curve is approximated in a stepwise fashion with the approximation becoming better as the respirable curve is divided up into increasing numbers of segments. It has generally been felt that three segments is satisfactory for most cases.A new version of the respirable impactor has recently been developed in our laboratory. This impactor approximates the ACGIH respirable curve in three steps at a flow rate of 30 liters per minute. However, unlike previous models where all of the particles larger than the three cut points designated by the three steps are collected upon one impaction plate, a separate impaction plate is now used for each of the three cut sizes. To approximate the respirable curve in three steps, the cut sizes must be 2.2, 3.5 and 5.8 microns diameter. Therefore, on each of these stages the particles collected will be the mass of particles that are larger than these three cut sizes. By determining the mass of particles collected on each of these three stages plus that on the after filter using Gravimetric techniques, some information can be obtained on the size distribution of the aerosol being sampled. Furthermore, the impaction plates of the three stages are rotated and the nozzles are placed in such a position such that a uniform deposit is obtained on each of the impaction plates. Therefore, the deposits collected are suitable for X-ray fluorescence analysis or other types of analysis where a uniform deposit is required."

Jan 1, 1988

By Van H. Manning

EXPLOSIVES RESEARCH. As the physical laboratories of the explosives section of the Pitts- burgh experiment station were equipped for testing the physical properties of explosives, both the Army and Navy Departments for many years had requested the Bureau of Mines to make such tests. Chemical control of the physical tests through analyses, heat tests, analyses of gaseous products of combustion, and sand tests was exer- cised through the explosives chemical laboratory. Often an investigation was cooperative between two laboratories. The explosives chemical laboratory also aided the work of the Ex- plosives Regulation both by chemical tests and investigation of acci- dents in explosives plants. COOPERATIVE WORK FOR ARMY AND NAVY DEPARTMENTS. The explosives chemical laboratory devised, at the request of the Bureau of Ordnance of the Navy, a more economical method of making hexanitrodiphenylamine. This problem was assigned to the Bureau of Mines by Dr. C. E. Munroe, chairman of the committee on explosives of the National Research Council, acting as the depart- ment of science and research of the Council of National Defense. Before the United States entered the war the following reports of investigations were submitted to the Army or the Navy: 1. Report of sensitiveness and relative efficiency of TNT and ammonium picrate, dated February 6, 1913, undertaken at the re- quest of the Chief of Ordnance. 2. Report of tests and examination of two samples of TNT and one of TNA for the Ordnance Department of the Army, dated August 5, 1915, was undertaken at the request of commanding officer, Frankford Arsenal. 3. Report of tests for sensitiveness to detonation of mercury ful- minate of 21 samples of TNT crystallized from various solvents, for the Bureau of Ordnance, Navy Department, dated June 17, 1916. 4. Report of tests of two samples of mercury fulminate for Frank- ford Arsenal, dated December 2, 1916, undertaken at the request of the commanding officer, Frankford Arsenal. After the United States entered the war the following reports of investigations were submitted: 5. Report of pendulum friction and large impact tests on two samples of "sodatol" and two samples of "amatol." The final report was dated July 20, 1918; and the preliminary report, May 15, 1918. This investigation was undertaken at the request of the Ordnance

Jan 1, 1919