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By R. H. Fernald

In 1900, as far as available records show, there were only two producer-gas power installations in the United States. In June, 1915, the number probably exceeded 1,000. Of this number, some 84.5 per cent comprised small plants using anthracite, and only about 15 per cent of the total number utilized bituminous coal and lignite. In addition to these, two plants used wood, and three or four used oil. In the main, however, the larger sized units are operating on bituminous coal and lignite.

Jan 1, 1916

By J. H. Wiggins

In 1919 the United States was threatened with a shortage of gaso- line. In spite of this well-known fact, a detailed field investigation has shown that in one stage only of handling crude oil the volume of gasoline that evaporates is equal to one-thirtieth of the country's yearly gasoline production. This loss occurs during the few days that the oil is stored on the leases before being taken by the pipe line, and in 1919, in the Mid-Continent field alone, it amounted to 122,100,000 gallons. Large as it is, it is only a part of the loss on the lease. Investigation has further shown that the gasoline in crude oil evaporates from one-half to six-tenths as rapidly as the same gaso- line after being distilled and stored, all evaporative conditions being the same. Many wastes in the oil fields are called "necessary." By this is meant that the cost of preventing the waste is greater than the gain through saving. Evaporation losses have fallen heretofore in this category, but now they must be considered unnecessary. In other words, it is no longer economical for any handler of crude oil to permit losses through evaporation. In accordance with its purpose of seeking to conserve mineral resources, the Bureau of Mines investigated the loss of gasoline by evaporation in the storage and handling of petroleum. Inasmuch as most producers had not decided that their losses justified cor- rective measures and no evidence was available on the comparative losses in various stages of handling the oil, the investigation was limited to determining by experiment and observation the nature and magnitude of evaporation losses, where the greatest losses are, and the factor controlling evaporation.

Jan 1, 1922

By R. H. Grau

Researchers from the National Institute for Occupational Safety and Health have demonstrated that mine-wide ventilation in large-opening stone mines can be improved by using low-pressure, high-volume propeller fans and constructing stoppings in key locations to direct and control airflow. In light of these findings, a comparative study was conducted to determine if a portable diesel-powered propeller fan could per-form more efficiently for dust dilution and transport than an axial vane fan for localized ventilation. The objective of this study is to evaluate both fan types for ventilation efficiency at an underground dump/crusher facility in a limestone mine. Results showed an improvement with the propeller fan to dilute both the respirable dust and the respirable silica dust around the dump/crusher facility. Overall, an average reduction of 20% in respirable dust and silica was observed at the dump/crusher location with the propeller fan.

By W. W. Scott

Measurements of the absolute value of electromagnetic noise and attenuation along a hoist rope were made in an operating hard-rock mine, Lucky Friday Mine, located near Wallace, Idaho. Spectra of electromagnetic noise generated by various pieces of equipment, spectra of specific noise signals at various depths, and noise and attenuation on the 4250 foot (1295 meter) hoist, were measured. Three techniques were used to make the measurements. First, noise was measured over the entire electromagnetic spectrum of interest for brief time periods. Data were recorded using broadband analog magnetic tape for later transformation to spectral plots. Second, noise amplitudes were recorded at several discrete frequencies for a sufficient amount of time to provide data for amplitude probability distributions. A third technique gave attenuation data through the direct measurement of field strength at various depths. The specific measured results are given in a number of spectral plots, amplitude probability distribution plots and amplitude curves as a function of depth.

Jan 1, 1974

By F. P. Haver

The Bureau of Mines has investigated the electrochemical reduction of lead chloride as a method for producing lead without the pollution problems associated with smelting. It was determined that high-purity metal (>99.9 pct Pb) could be obtained, using PbC12 prepared by ferric chloride leaching of galena concentrate: PbS + 2FeCl3?PbCl2 + 2FeC12 + S°. Optimum results in small-scale electrolytic tests were achieved with a bath consisting of 40 to 70 wt-pct PbCl2 dissolved in KC1-LiCl eutectic, an operating temperature of 450° C, a current density of 2.5 amp/in2, and an electrode spacing of 0.5 inch. In large-scale tests made to develop a cell design for commercial application, the optimum electrode arrangement proved to be a bipolar configuration with horizontal plates. This gave a current efficiency of 86 pct with an energy requirement of 0.52 kwhr/lb lead. To determine the effect of impurity buildup in the bath, 1,200 lb of PbC12 prepared by ferric chloride leaching of galena concentrate was electrolyzed over a period of 2 months. Little deterioration of the metal quality occurred in that time; all of the lead produced had a purity equal to or better than corroding grade (>99.94 pct Pb).

Jan 1, 1976

By C. C. Furnas

Despite the fact that a great many industrial processes depend on efficient contact between a gas stream and a bed of broken solids for their operation, the data in the literature are very meager. Several investigations3 have been undertaken, but the work has been limited in scope and application. BUREAU OF MINES PROGRAM OF RESEARCH For the past 10 years the United States Bureau of Mines has been engaged in research with the object of formulating a more or less complete quantitative theory of the workings of the iron blast furnace. Obviously, in order to do this one of the essentials is to have considerable definite information on the laws of gas flow through beds of broken solids. This report in a brief summary of the experimental work on the problem which has been done at the North Central Experiment Station. The complete report with more detailed tabulation of the data and explanations of the experimental procedure is in process of publication in the form of a bulletin.

Jan 1, 1928

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

By Joseph A. Vanous

The inductive communication system was developed under this contract for use in the hoist of deep mines. This program was a four phase program with experimental dual frequency equipment resulting from Phase I, emergency single frequency equipment developed under Phase II, and equipment documentation required under Phase III. An additional emergency system was provided under Phase IV.

Jan 1, 1976

By D. A. Larson

The Bureau of Mines conducted research to develop preliminary engineering data necessary if the cobalt-rich manganese crusts that occur in the Exclusive Economic Zone (EEZ) of the Hawaiian Archipelago are to be mined. The research was divided into the following sections: (1) physical, mineralogical, and chemical descriptions; (2) mechanical property testing, such as compressive strength, tensile strength, and a rippability index; and (3) mechanical cutting characteristics, including average and peak cutter forces, the specific energy, and cuttings size distribution. Section 1 utilized microscope, X-ray powder diffractometer, and electron microprobe analyses. Section 2 utilized standard mechanical property testing techniques. Section 3 utilized a converted planer mill with full-size coal cutters to fragment the crust and substrate samples. The manganese crust samples were mainly manganese and iron oxides and hydroxides with an average cobalt content of 1 pct and had a nucleus or substrate of rock or sediment. The significant results shown by the mechanical property and cutting tests are that the crust and all but two types of substrates (basalt and trachyte) are weak materials and easily cut with standard drag cutters. The crusts are generally comparable to medium hard coal in strength and in their resistance to cutting.

Jan 1, 1987

By Irvin Pritts

This report describes the design, fabrication, and testing of a prototype instrument which demonstrates the feasibility of determining respirable coal dust concentrations by light reflectance photometry. Coal dust is collected on a filter and the quantity collected is continuously monitored by reflectance-photometry. Light emission and detection is accomplished by reflective object sensors, which have both light source and detector in one chip. The use of a pulsed light source insures low drift characteristics of the measuring circuitry. The collection of the respirable coal dust on filters facilitates accurate calibration and also allows measurement verification, if desired, by well-accepted, gravimetric methods.

Jan 1, 1981

By S. M. Marshall

The investigations recorded in this bulletin were conducted by the Pacific Coke & Coal Co. in cooperation with the United States Bureau of Mines and the University of Washington. They cover one phase of a comprehensive investigation to determine whether coals from an extensive, undeveloped area of Pierce County, Wash., can be used in the manufacture of coke for the iron blast furnace. The completed investigation had three parts: (1) A geological survey of the coal property, (2) washing and crushing tests of the coals, and (3) coking and by-product tests. The geological survey, which was not conducted in cooperation with the Bureau of Mines and the University of Washington, included systematic tracing of the coal beds by test holes throughout the property, except some portions covered by an impenetrable layer of glacial drift. By this means all of the beds were correlated, their thickness and general character were determined, and tonnage estimates were made. Only such parts of the survey results as are necessary to a full explanation of the investigations described herein are included in this bulletin.

Jan 1, 1931

By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining the potential for reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A bibliography of pertinent literature is included as an appendix. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978

By Kenneth G. Skinner

The rapid growth of the metallurgical, chemical, and allied industries on the Pacific coast just prior to and during the war caused a sudden increase in the demand for refractories, which was the immediate cause of a revival in interest in refractory clays available on the Pacific coast, particularly in the Pacific Northwest. Population increases and shortage of shipping facilities caused an increase in the amount of various ceramic materials and products used and produced on the Pacific coast, with accompanying demand for information regarding sources of clay. In an effort to supply part of this information, the Bureau of Mines, in cooperation with the College of Mines, University of Washington, started a program in 1944 to test the refractory and other properties of clays from seven Pacific Northwest deposits that had been drilled and sampled as part of the Bureau of Mines alumina from clay investigation. Figure 1 shows the location of these deposits.

Jan 1, 1949

By William C. Cooley

This report includes a review of all relevant data on underground hydraulic coal mining technology collected during Phases I and II of the contract. Data collection and analysis procedures are discussed. Information is included on past and existing underground hydraulic coal nines in the USSR (27 mines), Poland (1 mina), Germany (1 mine), Japan (1 mine), Canada (1 mine), China (1 nine), as well as underground tests conducted in the United Kingdom (2 mines), and in the United States (5 mines). Data is also included on Czechoslovakia and New Zealand. In all operational hydraulic mines, coal is transported underground in flumes. In most cases, bituminous coal is broken by monitors with nozzle diameters larger than 16 mm (0.63 in.) and jet pressures of 50 to 125 atm (710 to 1780 psi). Technical design and performance data are included on all key types of equipment and components which have been developed for, used in, or which could be potentially be used in hydraulic coal mining systems. Data sheets are presented on 180 types of equipment, divided into 24 major categories. Where available, sketches, drawings, photographs, and price estimates are included. Data are included on pitching coal seams in the United States which potentially can be mined by hydraulic methods. Preliminary conclusions are presented, subject to revision as a result of economic feasibility studies to be completed during Phase III. An outline is presented of the final report, which will include economic studies and recommendations for research and development.

Jan 1, 1975

By R. W. Watson

A belt-wearable self-contained self-rescuer (SCSR) manufactured by the CSE Corp. and designated the "SR-1OO" was evaluated for safety in the underground mine environment by the U.S. Bureau of Mines. The evaluation consisted of laboratory tests on the chemicals contained in the unit and field trials to simulate the mine environment. This report summarizes the test results and compares the results with those from earlier tests with chemical and compressed oxygen self-rescuers. It was concluded that the new SCSR did not pose any different or more severe hazards than the earlier units. In view of the mine-proven safety record of the SCSR's now in service, no reason could be found to disallow use of the belt-wearable unit.

Jan 1, 1991

In 1990, the Bureau of Mines (BOM) conducted a mineral investigation of the mines and prospects in the East Mojave National Scenic Area (EMNSA), San Bernardino County, California During field work, BOM identified 701 mines and prospects in EMNSA for which the geology, mineral resources, and mining history were compiled and summarized. Analytical results for 1,188 rock samples collected are tabulated. Total value of identified resources in EMNSA is $5.0 billion. Twenty-four mines and prospects were deemed profitable under current economic conditions. Development could generate considerable economic benefits to San Bernardino County. Potential economic benefits from mining the deposits were evaluated under the following access restrictions for EMNSA: 1) full access, 2) HR 3460, and 3) S 11/HR 780. Under the full access scenario, cumulative mine revenues are $3.0 billion, cumulative personal earnings at mines and supporting industries are $0.94 billion, and annual jobs at mines and supporting industries are 2,379. Under HR 3460, mine revenues, personal earnings, and annual jobs are $2.9 billion, $0.88 billion, and 2,165, respectively. Under S 11/HR 780, mine revenues, personal earnings, and annual jobs are $1.0 billion, $0.32 billion, and 936, respectively.

Jan 1, 1990

By P. H. Mutschler

The Bureau of Mines studied the costs of transporting fossil fuels, coal, and residual fuel oil from areas of production to consumer regions. Transportation data were stratified by type of carrier, size of shipment, and distance to determine what general effects these variables have upon transportation costs. Economics of haul for coal exist for longer versus shorter distances, and for larger versus smaller trainload sizes. Tanker and barge transportation of residual fuel oil does not show economies of haul for longer distances. It is shown that tanker size and seasonal variation are primary factors influencing the cost of shipping. Railroad transportation data show that coal from western coalfields could be competitive with foreign residual fuel oil in selected midwestern fossil fuel markets. However, the western coal would not be competitive in the New England and the eastern seaboard energy markets.

Jan 1, 1973

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 S. H. Ash

A CLAY, sand, and gravel deposit known as the "buried valley" of the Susquehanna River is situated in the Northern field of the anthracite region of Pennsylvania near Wilkes-Barre. The presence of this buried valley and the uncertainty regarding the extent and physical condition of the water-bearing valley-fill deposits have made great care necessary in mining operations to avoid breaking the strata between the mine workings and the valley-fill deposits to the extent that inundation of the mine workings would follow. The principal factor that threatens to cut short the life of the anthracite industry, to curtail production, and to affect the economic structure of the people and business dependent on anthracite for their livelihood is inundation of anthracite mines (6,7).3

Jan 1, 1950

By J. A. Kost

The objectives of this contract were to determine the amount, size, and deposition of float coal dust (74 x 10 microns) generated during the mining and transporting of coal in underground U.S. mining operations. Rock dust distributed by trickle dusters was also sampled. In addition to four belt-transfer points, two continuous and two conventional mining sections were sampled at five mines located in Pennsylvania, West Virginia, Kentucky, and Illinois. Float-dust samples were collected on deposition pans; total airborne dust was collected with MSA Model C personal samplers equipped with Unico filter casettes; Andersen cascade impactors provided relative size distributions of the samples. Production, airflow, and water flow were monitored to examine their effect on dust levels.

Jan 1, 1981