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By N. A. C. Smith, A. C. Fieldner, R. R. Sayers

Gases and vapors given off by petroleum and its products have long been recognized as somewhat injurious, when inhaled in high enough concentrations. The petroleum industry has recognized these effects and has tried to minimize the possibility of employees encountering dangerous concentrations of the vapors. Petroleum gases and vapors have not, however, been considered as actively poisonous, in the sense that hydrocyanic (prussic) acid and phosgene are poisonous; men have been exposed to them repeatedly, and for long periods, without any marked ill effects. Light Mexican crude oil when first introduced into the United States for refining was handled in much the same way as was customary with other apparently similar crudes; but experience soon showed that some toxic substance escaped from the crude during production and transportation and in most of the refinery operations. After a preliminary investigation several of the larger companies decided that the gases from the petroleum were the source of trouble, and therefore took precautions, wherever possible, to protect the men from exposure to these gases. With the increasing use of Mexican crude, this problem has become important. The present report covers the work done on the subject by the Bureau of Mines and the Public Health Service under a cooperative agreement with the American Petroleum Institute.

Jan 1, 1925

By D. Harrington

"Up to the last 10 or 15 years, responsibility for accidents in mines was generally, though not universally, placed upon the person or persons immediately involved. Present-day thought is rapidly veering toward holding the industry responsible for accidents, with ultimate payment of the bill by the consumer, if financial expenditure should be necessary. While it is undoubtedly correct in principle that responsibility for accidents in and around mines should be shouldered by the employer and while it is probable that as time passes the burden will become even more definitely than now that of the mining companies, on the other hand it is an undeniable fact that large numbers of accidents occur through acts of omission or of commission of some person, very frequently the victim of the accident being the offender.Out of about 3,000 persons killed every rear in our -mines and quarries, nearly half or approximately 1,500 of the fatalities are due to falls of overlying material or of persons, about 500 to haulage, about 350 to fires and explosions, about 125 to explosives, approximately the same number to electricity, and about 300 to various miscellaneous accidents.Generally the accidents from falls involve but one or two persons at a time, and the tendency is now as it always has been to charge the victim or possibly a coworker with the responsibility. Usually this sort of accident occurs at or near a working face (statistics indicate that about 80 per cent of fatalities from falls of roof or rib occur near the face), and as it is Generally agreed that it is the duty of the worker to keep his working place safe, the worker and especially the face worker is given the blame in case of accident."

Apr 1, 1930

By Jon G. Bredeson

The electromagnetic noise that exists in a mining environment is quite severe and was shown to have been reasonably well documented by a number of researchers in the Phase I Report. The noise levels are such that prudent communication design requires the careful use of all the electromagnetic noise data available. A comprehensive survey was undertaken to determine techniques used in various industrial environments to achieve secure communications in the presence of electromagnetic interference. The techniques were given in the Phase I Report and are rudimentary, but have produced reasonably good results. A number of these techniques could be applied to the mining environment.

Jan 1, 1980

By Hillary W. St. Clair

This is an initial progress report on a theoretical study of the iron blast furnace. The purpose is to develop a thermochemical model that will simulate mathematically a real furnace. An analysis is made of the behavior of a hypothetical furnace, operating adiabatically on pure ferric oxide, graphitic carbon, and dry air. Relationships are derived for carbon consumption, gas composition, and reaction temperature for a furnace operating at steady state, and in which the smelting rate is slow enough for the gas and solids to approach thermal and chemical equilibrium. Analyses are made for two contrasting types of gas flow: (1) Nonturbulent flow, having no vertical mixing; and (2) turbulent flow, having perfect mixing during each step of the process. It is shown that some vertical mixing is essential for complete reduction of ferrous oxide and that the extent of vertical mixing is one of the critical factors in the behavior of the furnace, This analysis indicates that the thermochemical relationships in a blast furnace can probably be best simulated by a finite series of gas-solid reactors through which gas and solids flow countercurrently and in which the temperature and composition of gases and solids are assumed to be uniform. Any degree of vertical mixing can be approximated by the proper choice of the number of reactors.

Jan 1, 1963

By James D. Noll, M. Eileen Birch

A monitoring method for diesel particulate matter was published as Method 5040 by the National Institute for Occupational Safety and Health (NIOSH). Organic and elemental carbon are determined by the method, but elemental carbon (EC) is a better exposure measure. The US Mine Safety and Health Administration (MSHA) proposed use of NIOSH 5040 for compliance determinations in metal and nonmetal mines. MSHA also published a rule making for coalmines, but no exposure standard was provided. A standard based on particulate carbon is not considered practical because of coal dust interference. Interference may not be a problem if an appropriate size-selective sampler and EC exposure standard are employed. Sub micrometer dust concentrations found in previous surveys of nondieselized, underground coal mines were relatively low. If a large fraction of the sub micrometer dust is organic and mineral matter, sub micrometer EC concentrations would be much lower than sub micrometer mass concentrations. Laboratory and ?eld results reported here in indicate the amount of EC contributed by sub micrometer coal dust is minor. In a laboratory test, a sub micrometer EC concentration of 31µg m 3 was found when sampling are spirable coal dust concentration over three times the US compliance limit (2mg m3). Laboratory results are consistent with surveys of nondieselized coal mines, where EC results ranged from below the method limit of detection to 18µg m 3 when size-selective samplers were used to collect dust fraction shaving particle diameters below 1.5µm sub micrometer EC concentrations were ?7µg m3. In dieselized mines, sub micrometer EC concentrations are much higher.

By Clayton M. Rumsey

No producing or developing mines nor known mineral resources are in the Lower Saline Valley Wilderness Study Area. The inactive Bonanza Prospect has low potential for copper-gold-silver resources. Stone and sand and gravel deposits in the WSA do not constitute mineral resources because transportation costs to major markets are prohibitive. INTRODUCTION The Lower Saline Valley Wilderness Study Area (WSA) covers 2,241 acres in southeast California adjacent to and west of Death Valley National Monument (fig. 1). Access to the WSA is by the Saline Valley gravel road 28 mi northerly from its junction with State Highway 190. The junction is about 35 mi southeast of Lone Pine, CA. The WSA is characterized by moderate to steep, sparsely-vegetated slopes; elevation ranges from about 1,800 ft to 3,560 ft.

Jan 1, 1984

By T. Bajpayee, J. Ellenberger

Microseismic monitoring and evaluation is one aspect of the National Institute for Occupational Safety and Health (NIOSH) research program. Roof falls are often preceded by a period of elevated microseismic activity, but not all periods of elevated activity result in a roof fall, nor do all roof falls occur after some amount of elevated activity. The objective of this study is to review periods of elevated microseismic activity and determine whether fracture activity rate can be used to anticipate the initiation of roof falls. The study was carried out at an underground limestone mine where major roof falls are associated with excessive horizontal stress. The progression of roof falls was detected by the microseismic signature produced by the rock falling from the mine roof onto the mine floor, which is termed a roof fall impact event. A total of nine elevated fracture activity periods that resulted in seven major roof falls were examined. It was observed that elevated fracture activity preceded the initial roof fall impact event in three out of four major roof falls. The initial impact event was not identified for the remaining three roof falls. Fracture event rates were analyzed and a roof fall alarm trigger of five fracture events in a ten minute time period was established for this test case. The fall alarm trigger was tested against six of the elevated activity periods. Four roof falls occurred in the six periods of elevated activity, and two would have triggered the alarm before the roof fall occurred, while two false alarms were generated. The results show that limited success would have been achieved by the microseismic system as a roof fall alarm trigger. However, the trigger would have been successful at warning of the onset of elevated activity, allowing mine employees to respond appropriately. The study highlighted some issues with implementing such a system in an operating mine, including the need for real time identification of fracture related microseismic signals among mining induced signals, and accurate location and identification of fracture clustering.

By P. L. Woolf

Blast furnace coal injection tests conducted by the Bureau of Mines in cooperation with a consortium of 22 steel companies in 1963-1964 are described. These tests were part of a program of extensive investigation of auxiliary fuel injection in the Bureau's experimental blast furnace located at Bruceton, PA. Seventeen coal tests are described on various coals ranging from anthracite to subbituminous. Factors affecting maximum rates of injection were studied. These included coal size, coal type, and oxygen enrichment. The effect of high sulfur content coal and the means to control metal sulfur were investigated. An epilogue briefly describing the commercial experience with coal injection from 1960 to the present has been included.

Jan 1, 1985

By Wilbert J. Huff

The organization of the'Explosives Division is indicated by the accompanying chart (fig. 1). As this has been discussed in a previous report3/, it will not be considered further in this report. The activities of the various units are outlined below. I. INFLAMMABILITY OF GASES AND VAPORS4/ Determination of the Explosion Hazards of Combustible Gases and Vapors Found in Mines and Industries The Explosives Division maintains, at the Pittsburgh Experiment Station, a laboratory specially equipped for the determination of the explosion hazards of combustible gases and vapors. Of particular importance, is the determination of the chemical composition within which explosions may occur and beyond which there is no danger of explosion, combustion or inflammation. These limits, known as the limits of inflammability, as determined by this and other laboratories, have been compiled in Bulletin 279 of this Bureau. The last revised edition (1931) of this bulletin has been exhausted. Since it was published, the Pittsburgh laboratory has determined the limits of about 40 combustibles and has ascertained more precisely and accurately many previously published limits.

Jan 1, 1938

By Frank E. Cash

As a part of its safety program the United States Bureau of Mines has fostered the development, use, and improvement of portable electric mine lamps. Although there is still need for better illumination in mines and the replacement of open lights has been slow, improvement in electric cap lamps and increase in their use indicate one phase of recent progress toward safer and more efficient mining This report is the result of a recent survey of electric-lamp installations in the Alabama mining; district; it shows the misuse, increase in use, and relation to certain classes of accidents of these installations.

Jan 1, 1935

By Dennis R. Dolinar, Gabriel S. Esterhuizen

In this National Institute for Occupational Safety and Health (NIOSH) investigation, numerical modeling is used to evaluate the degree the pillar strength is increased with a rectangular pillar over a square pillar. Three-dimensional models are developed with pillar sizes and geometries typical of underground limestone mines in the United States. Physical properties for the models are based on geotechnical surveys of nearly 30 underground limestone mines. To examine the effects of pillar length on pillar strength with the modeling, a parametric study was conducted where the pillar width was held constant while the length and height were varied resulting in width-to-height ratios ranging from 0.5 to 1.5 and width to length ratios ranging from 1 to 6. There are two aspects to pillar strength and failure. At relatively low stresses, pillars can fail as a result of geologic structure. At greater depths and sufficient extraction ratios, the pillars can also fail as a result of the vertical stresses exceeding the pillar strength. The effects of increasing pillar length regarding both strength aspects are presented in this study. Equations were developed for the increase in pillar strength with both height and length based on the model results. The results from these equations were compared to those from previously developed empirical equations for rectangular pillars. For the more slender limestone pillars with a width-to-height ratio below one, there is little increase in pillar strength for length-to-width ratios above 2 and almost no increase with length for a width-to-height ratio of 0.5. Only with the more squat pillars is there a significant improvement in strength with length. The gain in pillar strength with length for the pillars is explained by the change in the ratio of the area of the pillar affected by the ends to the area of the pillar. For the squattest pillar, the change in strength is also affected by an increase in pillar confinement along the central length of the pillar as the pillar transitions from a square to a long rectangular pillar. With geologic structure, added pillar length can significantly improve the pillar strength, depending on the strike of that structure with respect to the long pillar axis.

By John R. Parker

Work places of an underground coal mine are required (30 CFR 1719) to be illuminated while self-propelled equipment is used. Permissible machine mounted systems have been developed and applied satisfactorily to many mining operations. However, some low seam and thin seam equipment has been difficult to illuminate because reliable, direct current systems and compact, low output, low glare luminaires were not available. This program resulted in the design and prototype construction of compact, low glare luminaires and AC and DC power systems, particularly suited to resolving illumination problems on low and thin seam mining equipment. Design objectives were based on enhancing the prospects for thin seam illumination solutions through definition of a product which could challenge markets enjoyed by higher glare luminaires and through reduction of technical risks associated with any new product development as well as the MSHA certification process.

Jan 1, 1982

By C. R. Carpenter

A dynamic gas-mixing system assembled by the Bureau of Mines for the generation of precise gas mixtures from sources of concentrated or pure gases and diluent gases is described. A set of electronic mass flow controllers with maximum flows ranging from 10 to 5,000 ml/min, a so-called Pure Air Generator, and gases in cylinders are used to generate differing gas concentrations. The repeatability of the delivery rate of a flow controller, measured on different days, has a precision of 0.3 pct of the setting. This dynamic gas-mixing system reduces the cylinder inventory and the demurrage charges for special gas mixtures. Gas mixtures that cannot be shipped commercially, such as flammable mixtures of methane in air, can be conveniently prepared by this system. The maximum dilution ratio is 2.5 x 104. Thus, gas mixtures can be made over a wide range of concentrations, from the percent region (by dilution of a pure single-component gas) to fractional parts per million (by dilution of a premixed standard, e.g., a 1,000-ppm mixture). This system is especially useful in determining the response of gas detection devices over the entire range of their measurement. Because the controllers are voltage controlled they lend themselves easily to automated control using computer-based systems.

Jan 1, 1983

By John G. Palmer

Continued development of an especially impregnated silica gel capable of reversible chemical detection of carbon monoxide (CO) was reported. The affects of changes in mine-related ambient conditions on the detection catalyst's response were explored. Temperature, humidity, and several interfering gases were found to affect the detection catalyst. The interferents include hydrogen sulfide, nitrogen dioxide, acetylene (and methylacetylene), and ammonia. High humidity decreased the detection catalyst's sensitivity to carbon monoxide for some formulations. Increasing temperature generally decreased the reaction time of the detection catalyst with carbon monoxide. Badges and carriers for the visual presentation of the detection catalyst were constructed. Several variations of these devices included provisions for absorbants and filtering agents which help protect the detection catalyst from gaseous interferents. A variety of catalyst support agents were tested in an effort to find the most suitable. Included were alumina, magnesium oxide, magnesium silicate, and several forms of silica gel. In addi tion to free-flowing forms of these sorbents, thin layer chromatography plates coated with cellulose, alumina, and silica gel and newly developed PTFE entrained silica gels were examined. A limited physical, chemical, and mechanistic characterization of the detection catalyst and the materials used to prepare it has been carried out. Metal component ratio studies, spectral, analytical, pH, and rate measurements were done.

Jan 1, 1982

To allow the controlled yielding of mine walls in order to reduce rock-burst hazards and reduce maintenance caused by excessive squeezing forces. Approach Rock bolts that elongate and continue to sustain a load, have been fabricated and tested. This device is an adoption of a concept originally developed in South Africa for use where unusually adverse conditions may warrant the added cost. How It Works A coupling in the rock bolt allows controlled elongation if the load increases beyond the bolt's design strength. (The load can build up either slowly, as during heaving, or rapidly, as before a rock burst.) The elon¬gation of one or more rock bolts surrounding a mine opening, allows the rock to move from its original position to c new position in a controlled manner. This movement relieves the rock stresses, and the mine opening reaches a new state of equilibrium. The elongatible coupling of the rock bolt consists of a

Jan 1, 1977

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag composition. Liquidus and solidus temperatures and solid solubilities were determined for the BaF2-Y203 system, and the information is presented as the phase diagram. The phase diagram was constructed from data obtained by ceramography, X-ray diffraction, and thermal analysis of specimens encapsulated in small molybdenum ampoules. The data indicate a simple eutectic system with maximum terminal solid solubilities of less than 1 mole pct. The eutectic temperature is 1,343° C, and the composition of the eutectic is less than 1 mole pct Y203.

Jan 1, 1970

By Irving Hartmann

Rock-dusting of coal mines is a most important safety measure for preventing or limiting the propagation of explosions. The Bureau of Mines has recommended for many years that rock dust be distributed on the top, ribs, and floor of mine entries and other workings of all bituminous coal and lignite mines in sufficient quantities to maintain the incombustible content of the dust above the minimum requirements. Rock-dust barriers constitute a secondary safeguard used occasionally to complement generalized rock dusting at entrances to panels and side entries or at other locations. In general, rock dust can be applied effectively with modern rock-dusting machines. However, in thin coal beds, in certain back entries, and in some other areas, rock-dusting machines cannot be used conveniently. Furthermore, many small mines find the purchase of machines costly. In such cases, rock dust is not used at all, or else it is distributed by hand, a relatively slow and costly procedure. In recent years some coal mines have started applying rock dust with the aid of permissible explosives. This may be done in various ways. One method consists in placing a stick of explosive on the floor of a room or entry midway between the ribs and covering the stick with two bags of rock dust that are slit on top and set crosswise one above the other. The explosive is then fired, causing the rock dust to be distributed on the nearby roof, rib, and floor surfaces. The procedure is repeated at desired intervals until the entire area is rock dusted. The method is claimed to be rapid, safe, and inexpensive.

Jan 1, 1950

By Charles L. Kimbell

Virtually every available measure of total world mineral industry activity demonstrated that 1982 was little, if any, better for the industry than 1981 had been. Levels of production, trade, and consumption for virtually every major commodity declined; unit prices for most commodities fell, particularly in terms of constant dollars, and as a result of cutbacks in output and lower prices, capital available for investment within the industry was reduced. These conditions, coupled with the existence of considerable idle capacity, tended to retard investment, although there was an upturn in U.S. oil industry investment overseas. Despite the overall depressed situation of the world's mineral industry, there were indications of possible improvements in market economy countries near yearend, as output of some materials increased marginally and as prices for some mineral commodities reversed their downward trends. The downturns in total world mineral industry activity were not universal from the viewpoint of individual countries. Indeed, output of a number of commodities increased in centrally planned economy countries, and these gains were insufficient to offset declines in market economy countries, thereby sharply altering the proportion of total world output accounted for by each of these two groups of countries. There was a similar shift in consumption on a percentage basis.

Jan 1, 1984

By Martin Hertzberg

This Bureau of Mines study concerns the use of the tube bundle method as a sensitive and reliable detector of mine fires. The method involves the pneumatic, sequential sampling of many points in a system through branching tube bundles that lead to a single analytic station of high sensitivity, good reliability, and convenient location. Two serious limitations inhibit its use: the relatively slow response times for long lengths of narrow sampling tubes and the wall-diffusion losses for submicrometer smoke particulates. These limitations were quantitatively evaluated by measuring tube transit times and smoke particulate transmissions as a function of tube length, diameter, and pressure drop. The comparison of the data with theory offered the challenge of extending the classical, incompressible flow solutions to the two compressible cases: isothermal and adiabatic. New equations were derived for these cases, and the measured transit time data gave reasonable agreement with calculated solutions in both the laminar and turbulent regimes. The measured transmission losses of smoke particulates from several combustion sources compared favorably with those expected from Brownian diffusion losses to the interior walls of the sampling tubes. Traveltime and smoke transmission graphs are provided and, pump power requirements are estimated.

Jan 1, 1976

By John D. Bardill

This report covers magnetic surveys in the Dannemora arca , which was part of a general survey of magnetite deposits in New York started in 1943 . The objective of these surveys was to afford a basis for the selection of exploration projects .

Jan 1, 1947