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By Clyde L. Brown

The ignition source of fires and explosions in coal mines is sometimes difficult to explain because resulting widespread destruction often erases valuable evidence that might reveal the cause. However, through years of experience, investigators have been able to piece together enough evidence to establish the reasons and, thereby, have been equipped to recommend corrective or preventative measures. The pattern of hazards is not constant. It changes with the development of new practices and new equipment. Important among the new hazards to coal mining are those introduced by electricity. In addition to the dangers of electric shock, fires and explosions from heat and arcs, and premature blasts, certain others have developed as a result of stray electric currents from direct-current traction systems. The conventional direct-current power-distribution system in coal mines is conducive to electrolysis damage to mine tracks, metallic pipelines, grounded power conductors, and structures in a position to become conductors of stray currents. The voltage drop resulting from power demand on intentionally grounded power conductors and accidental grounds on insulated conductors are common sources of stray currents in coal mines. Uncontrolled electric cur-rents flowing through the earth and metallic structures can be a menace, and these contribute to the estimated $6,000,000,000 annual loss caused by corrosion. The purpose of this publication is to discuss some of the electrolysis hazards in the coal-mining industry and to outline corrective measures to alleviate them.

Jan 1, 1962

By Richard C. Moore

The U.S. Bureau of Mines contracted a study to estimate what effects the underground mining of thick coal seams in the western United Slates would have on the surrounding water resources. Potential coal fields in the western United States where this type of mining might occur were identified. The foreign literature was searched for studies of effects on hydrology from thick seam underground coal mining. Based on the limited information obtained from the foreign literature, estimates of the effects of this type of mining on the ground and surface water in the western states were made.

Jan 1, 1980

By O. C. Blade

"INTRODUCTION This report on the properties of motor fuels sold through service stations in the United States is a continuation of a series of reports made in accordance with a cooperative agreement between the Coordinating Fuel Research (CFR) Com¬mittee of the Coordinating Research Council (CFC) 3/ and the Bureau of Mines of the United States Department of the Interior. The first of these reports presented data on motor gasolines sold during the winter of 1935-36. 4/ Further re¬ports were issued describing motor gasolines sold during the succeeding summers and winters to and including the summer of 1941.4/ No reports were made on motor gasolines sold during the winter of l941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed. The present report presents analytical data for 3,011 samples, representing the products of 113 companies. Most of the samples represented in this report were obtained during July and August 1946. As in previous surveys the companies covered by the survey include both large and small suppliers. Conforming to former reports, the data cover three groups of samples - regular-price, premium-price, and third-grade gasolines.As the number of analyses submitted for samples of third-grade gasoline are not considered adequate to represent this type of motor fuel, data for the analyses have not been averaged, but the individual items are tabulated. The number of samples, items, and brands comprising each group is as follows: Regular-price, 1,585 samples, 311 items, and 99 -brands; premium-price, 1,422 samples, 280 items, and 94 brands; third-grade, 4 samples, 4 items, and 4 brands. The meaning of these terms as used in the survey is as follows:"

Dec 1, 1946

By E. Morrice

The metallurgical laboratory data developed in this study indicate an improved electrowinning process for producing higher purity cerium ingot. A typical sample of the Reno electrocerium contains 99.9 weight-percent cerium and the following impurities: Total other rare-earth elements, less than 0.04 percent; iron not detected; silicon and aluminum, less than 0.02 percent each; calcium plus magnesium, less than 0.01 percent; carbon, 0.01 percent; oxygen, 0.002 percent; hydrogen, 0.0003 percent; and nitrogen, 0.0015 percent.

Jan 1, 1960

By Frank J. Perzak

This report describes a U.S. Bureau of Mines study on the hazards of large-scale conveyor belt fires in underground coal mines, as a function of both air velocity and distance from belt surface to gallery roof. The fire hazards considered were smoke obscuration, toxic effects of carbon monoxide (CO), and elevated air temperatures downstream of the fire. All of these hazards scale with the ratio of fire intensity to ventilation airflow. These hazards were all found to be greater at the lower belt-to-roof distance, owing to the greater fire intensities that resulted. The hazards of smoke obscuration and elevated CO levels were greater at lower air velocities. Smoke obscuration was found to be the earliest hazard, reaching critical levels before the stage of belt flame spread. Critical levels of CO and downstream air temperatures were not reached until the later stages of flame spread. Fire growth rates during rapid flame spread were much greater than rates measured during the early stages of belt burning. Data were analyzed to determine the early-warning capability of fire sensors. Smoke sensors provided the earliest warning, followed closely by CO sensors. Thermal sensors did not exhibit any early warning capability.

Jan 1, 2010

By B. W. Dunning

The Bureau of Mines investigated the concentration and distribution of precious metals in the various fractions produced from mechanical processing of obsolete military electronic scrap. Whole avionic units, printed circuit cards, and electrical connectors were processed and analyzed. Materials recovered included baghouse lights, wire bundles, mag-netics, and metal concentrates from eddy-current and high-tension sepa-ration. Higher value fractions were processed by a commercial toll refiner for recovery of gold and silver. Lower value fractions were analyzed by the Bureau. Three fractions, the lights, wire bundles, and metallics from high-tension separation, contained most of the precious metals. Depending on the type of scrap feed, these fractions represented 34 to 60 pct of the original sample weight. Collectively, they represented 68 to 97 pct and 75 to 98 pct of the contained gold and silver, respectively.

Jan 1, 1983

By Frank L. Wideman

THE TREND towards larger quantities of waste in materials handled at metal and nonmetal mines (excluding fuels) continued. A gain of 10 percent from 1962 in the tonnage of waste removed in mineral operations reflects the kind of technological problems being encountered. Technology has a major role in the mineral industry in the task of supplying raw materials obtained from resources occurring beneath the surface of the earth and used in manufacturing commodities essential to modern living. Changes in technology are often brought about by such factors as variations in economic conditions, differences in physical properties of raw material and changes in mineralogical compositions of ore. Mining is usually begun on the richest and most accessible of known deposits, and when these are exhausted, is continued with leaner ores or with less accessible deposits that are either lying at greater depths or are more remote from markets. The increasing difficulties of extraction and depletion of reserves are offset by improvements in extraction technology, improved transportation, and exploration for new deposits. Although depletion has prevailed at many individual mines and in many districts, technology has been the means of providing for increasing demands of an expanding economy with adequate supplies of minerals despite either the changing character or decreasing grade of certain ores. This has been accomplished by various methods applicable to minerals. Among the implements of technology are utilization of lower grade or more complex refractory ores by mass mining, concentration, processing, recovery of byproducts, and mechanization. Better methods to find concealed deposits or to penetrate to greater depths also have been helpful in maintaining a supply of particular minerals.

Jan 1, 1964

By Northcutt Ely

This volume- summarizes mining and petroleum legislation in 18 European jurisdictions. Within these jurisdictions, primary attention is given to requirements that must be met in each country for acquisition of rights to permit development of mineral resources. Coverage includes: First, identitication of the controlling laws or statutes governing minerals acquisition and reference to the administrative authority; second, analysis; of the laws governing mines and quarries and their products; third, analysis of laws applicable to natural gas, petroleum, and related materials; and fourth, mention of laws regulating offshore operations. Where pertinent, sections dealing with historical background or administration have been added in countries where minerals are subject to control of States or Provinces, those areas are considered separately from the central government.

Jan 1, 1974

By C. H. Fisher

[Mxny methnhs of ,analyzing tpr oils fnr thoir tar acid ~nd base cnntent hava boon employL~d in connection mith both ac~d,.mic and. industrial investigs- tions. Mnst of thznu nnalyticel proc?durn~s aro bpsed nn th; diminution in volums caused by extract lon sit5 alkali 5 minL+ra,l acids (cantrsction rn,>thod) , although othrr mr~thrids havu &apos;sL<on ?q~lnglt 8 . In many instmccs th-: donti ti on of RT~ m~lytic~l m ithod was not ;r.:c ~d~d by ~d.jqunt9 study, and, ns 3 cone+ qucnce, tha lit .,ratur ? on thls sub,jr:.ct is consoScuous for its cnntr~dictnry . claims and rocnmmondatinna.. 1.t tiR.s b9~n shoyn in th;, cnsn of c.lrtn.in synth?tic solut innsfi/ thnt larg~ jr-orn sny rcsult if th2 ,mnlysis is c~rri~d out by sim~la extraction wi.th alidi r.nd min 3rd ncids.]

Jan 1, 1937

By V. F. Parry

The major industrial uses of char or semicoke produced by low-temperature carbonization of coal4/ are as fuel for generating electric power, for blending with metallurgical coking coal as a substitute for low-volatile coals, and for gasification to produce synthesis gas for chemical purposes. This paper discusses various methods for carbonizing coal, emphasizing processing of the noncoking coals to produce char for thermal power-plant fuel and for blending with metallurgical coking coals and tar for chemical use. Low-temperature carbonization is a relatively simple processing step involving heating coal to about 900° to 1,200° F. to decompose the coal into 4 main products: (1) Semicoke or char; (2) complex, partly oxygenated liquid hydrocarbons or tar; (3) fixed gases; and (4) water. If the coal is heated rapidly under conditions that prevent decomposition of the primary products, 68 to 87 percent of the net heat in the raw coal is left in the char and 10 to 23 percent of the potential heat appears in the primary tar. Fixed gases represent approximately 7 percent of the heat and approximately 2 percent is lost or dissipated in the reactions of decomposition. Considering the different ranks of coal in the United States, the yield of tar will vary from about 9 to 44 gallons per ton, therefore it is important that each coal be carefully considered if it is to be carbonized for industrial use.

Jan 1, 1955

By William H. Tavenner

1. The 1952 Annual Report of the West Virginia Department of Mines lists nine beds that arc being mined in Logan County, of which the Cedar Grove and Chilton are the most important. The Cedar Grove group, No. 2 Gas, and Alma beds have the largest remaining reserves, in the order given. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 5,411 million tons as of January 1, 1954. Of this total, 3,939 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics were too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimate reserves.

Jan 1, 1956

By R. Ward Stahl

The underground junction or intersection is analogous to the doorway or window in a building in that the continuous wall or support for the overhead structure has been weakened by making the opening. Some type of bridge or support seems necessary to prevent roof sag and possibly eventual failure at this point, although frequently it appears that little is done until a fatal accident induces action. The intersection generally represents less than 15 percent of the exposed roof area. As a result of recent multiple fatalities, some of which occurred at or near intersections, the Bureau of Mines was asked to examine the junction-support problem more thoroughly and to report its findings. A national survey of the junction-support systems in use has been made by correspondence, and the local area has been canvassed rather thoroughly to determine just what and how much is being done.

Jan 1, 1962

By A. J. Kraemer

The twenty-fourth of a series of semiannual surveys pertaining to motor gasoline marketed in the United States was made by the Bureau of Mines in August, 1931. The first part of a report giving the results of that survey as they pertain to specification data is given in this paper. A companion report, Part II, is in preparation and will discuss the results of other determinations made on the samples, including octane number ratings on the individual samples (to be made by the Bureau of Standards) and results of the determination of gravity, color, doctor test, and "gum" content by the copper dish method and the Bureau of Mines steam-oven method. The retail price and the tax at the time each sample was taken will also be reported.

Jan 1, 1932

By P. D. Lindahl

[A cost/benefit analysis was conducted by comparing the industry cost to protective structures on low-coal face equipment with the benefits paid for injuries/fatalities considered preventable by the use of these structures. Th industry costs were based on estimates by OEM&apos;s and rebuild shops for install protective structures on new and rebuilt face equipment. The accident benefit was based on evaluations performed by the USBM Accident Cost Indicator Model. Industry wide population data were developed on low-coal face equipment and injuries/ fatalities preventable with protective structures. The results of the analysis are to be used as a tool by USBM in determining the feasibility of continuing development of cab and canopy technology for low-coal equipment.]

Jan 1, 1983

By Alvin Kaufman

Increased exploration in Alaska has resulted in many requests to the Bureau of Mines for facts about the mineral resources and mining conditions in the Territory. This report presents information about the minerals of Southeastern Alaska and the factors that affect development of a mining industry in that area. Southeastern Alaska is a narrow coastal strip of rugged mountains and many islands. The climate is mild, with an average annual temperature of 40° and heavy rainfall. Geologically, the region is favorable for deposition of ore; geographic-ally, it is difficult to prospect and to develop, except along areas immediately adjacent to the coastline.

Jan 1, 1958

By Leslie H. Sharp, Martin J. Gavin

"Introduction.Investigations of the oil shales of the State of Colorado were begun February 1, 1920, by the U. S. Bureau of Mines and the State of Colorado, under cooperative agreement entered into by the Bureau and the State, funds for which were provided by the State. The investigations are for the purpose of determining by large-scale Laboratory retorting tests, those conditions which will produce optimum yield of best quality products from Colorado shales. (For an outline of the work and description of the apparatus, see Gavin, Martin J., and Sharp, Leslie H., ""investigations of the Fundamentals of Oil-shale Retorting,"" Reports of Investigations, Bureau of Mines, July, 1920.)In the preliminary work which is usually required when a new material is being dealt with, certain physical and chemical constants of the shales being investigated, and their products, were determined; these data will be of much value not only to the thorough retorting tests now under way at Boulder, but to engineers who will design and construct oil-shale plants. While the figures presented in this report apply only to the shale used in the determinations, strictly speaking, the shale used was selected to represent, as well as possible, an average of the massive type of oil shale encountered in Colorado. The figures, therefore, can probably be applied with little danger of serious error to any massive Colorado oil shale which yields in the neighborhood of a barrel (42 gallons) of oil to the ton.This paper is based on a more complete article now being prepared in which experimental methods are explained in full, and complete experimental data. For the purpose of presenting the data with as delay as possible, it has been decided to anticipate the more complete article with the present report."

Aug 1, 1920

By Doerner H. A.

From thermodynamic calculations Maier predicted that zinc oxide and methane would react at specified temperatures substantially according to equation (1). (1.) ZnO + CH4 = Zn (gas) + CO + 2H2. Other reactions that may take place are (2.) CH4 = C + 2H2. (3.) ZnO + CO = Zn (gas) + CO2. (4.) ZnO + H2 = Zn (gas) + H2O. Maier predicted that 870°C would be the critical temperature above which reaction (1) would take precedence over reaction (2) and that reaction (1), at equilibrium, would be substantially complete at or above 927°C. Theoretical considerations indicate that reaction (1) is reversible: this is supported, but not proved, by experimental data. The other reactions are known to be reversible. At low temperatures reaction (2) requires a catalyst and it is slow below 1000°C. Reactions (3) and (4) are rapid, but the equilibrium constants are such that only small concentrations of CO2 or H2O can be produced below 1000°C. Maier calculated that CO2 should not exceed 0.5 per cent at 870°C., and the calculation for water vapor gives a still smaller order of magnitude.

Jan 1, 1931

By S. Gallagher, A. G. Mayton

Back injuries account for a high proportion of lost workdays in the mining industry and are a leading cause of disability in mine workers. Two risk factors for low back injuries are manual lifting and whole-body vibration exposure when operating mobile equipment. Recent research has shed light on possible mechanisms through which low back injuries may occur, and the results of these studies can be used to improve the design of lifting tasks and seats to decrease injury risk. This article discusses recent research results and how this knowledge can be leveraged to reduce the risk of low back pain.

By B. W. Gandrud

To say that the treatment and handling of the "fines" is the most difficult phase of coal preparation is probably an understatement of facts. It is the fine sizes from about 1/16-inch to 0 that are mainly responsible for the inescapable sludge and slurry problems at plants using wet methods of preparation. Sludge and slurry are a problem from the standpoints of both cleaning and dewatering. They cannot be cleaned satisfactorily by "gravity" methods, which are used so extensively on coarser Sizes, due to the fact that fine sizes, particularly from 65-mesh to 0, do not follow the same laws of settling as do the coarser sizes. Although fine sizes are cleaned more successfully on wet-wash tables than in jigs, even tables as usually operated in coal-preparation plants fail on sizes below 100-mesh. As to other phases of the, sludge and slurry problem, wet coal preparation plants are almost universally beset with troubles in connection with the recovery and dewatering of the fine sizes from about 14-or 20-mesh to 0. The sizes finer than 100-mesh further complicate the problems in a wet preparation plant by their tendency to stay in suspension and build up a troublesome load of solids in the circulating water. In order to prevent too much trouble from this source, it is, customary at most plants to bleed a fair-sized stream out of the circulating system continuously and replace it by addition of fresh make-up water. The slurry water withdrawn from the circuit is usually run to waste, in which case it carries with it a considerable amount of fine coal, thus increasing the "washer loss." Another evil results from wasted slurry water in that quite often it finds its way into creeks and larger streams, creating stream-pollution problems.

Jan 1, 1948

1. ACKERMAN, C. L. The Binary System Manganese-Zinc. Ztschr. Metall., vol. 19, 1927, p. 200. 2. ADKENASY, P., AND KLONOWSKY, S. Über die Manganatschmelze. Ztschr. Elektrochem., vol. 16, 1910, p. 107. 3. AKTIEBOLAGET FERROLEGERINGAR (assignees). Method for the Manufacture of Manganese Alloys Poor in Carbon or Silicon or Else Manganese. British Patent 163262, Apr. 28, 1921; U. S. Patent 1480267, Jan. 8, 1924. 4. Method of Producing Manganese or Manganese Alloys Poor in Carbon or Silicon. British Patent 174923, Jan. 25, 1922.

Jan 1, 1934