Search Documents

By G. E. McClelland

As part of its mission to assure an adequate domestic supply of metals essential to the Nation's welfare, the U.S. Department of the Interior, Bureau of Mines, investigated a particle agglomeration technique as a means for improving the flow of leaching solution through heaps of clayey or finely crushed, low-grade, gold-silver ores. Bench-and pilot-scale experiments showed that the percolation rate of cyanide leaching solution was markedly enhanced by mixing the ore with a portland cement binder, moistening the mixture, and mechanically agglomerating and aging the feed prior to heap building and leaching. The rate of gold and silver recovery markedly increased because of the increased, uniform percolation of leaching solution through the agglomerated feed. The use of concentrated cyanide solution instead of water during the agglomeration procedure decreased the leaching time required to obtain maximum recovery. Results of bench-and pilot-scale experiments are discussed.

Jan 1, 1981

By Jr. Reistle

The tests reported in this paper were made in the East Texas field in the summer and fall of 1932 as a part of the Bureau of Mines study of the operation of flowing wells and reservoir performance; and to determine, if possible, the minimum reservoir pressure necessary to produce the wells in this field by natural flow through different sizes of flow strings. The minimum reservoir pressure that would be required to Maintain natural flow through 2 1/2-inch tubing was determined experimentally for the existing energy conditions in the East Texas field. With the present available data, however, it is impossible to predict accurately or to determine by calculation the necessary energy requirements for maintaining the vertical flow of oil and gas mixtures under all conditions. Although some valuable data were obtained which seem to have application to the solution of problems involving vertical flow, this important research of the petroleum industry is so involved that more study of the complicating factors influencing the flow of oil-gas mixtures through vertical pipes is required.

Jan 1, 1933

By Joseph L. Buckley

A total of 55 conveyor belt fire tests were conducted in the Bureau of Mines Fire Test Gallery, located at the Factory Mutual (FM) Fire Test Center West Glocester, R.I. The objectives of these tests were to: 1) determine the fire resistance and burning characteristics of various conveyor belt materials under simulated mine conditions; 2) provide essential data for designing a reliable bench-scale conveyor belt fire resistance test; and, 3) determine fire test conditions that will discriminate between low, moderate and high fire resistant materials. Belts, representative of those which mold he found in underground coal mines were examined under n umber of experimental conditions which included; ignition intensity; air flow rate; ratio of belt bright (h2) to overall gallery height (h1); exposure time; and, belt width. It was found that fire propagation could be achieved for some "fire resistant" belts (complying with the present Schedule 2G standard for approval) when exposed to an Ignition source of =6000 Btu/min for a 15-min period at a belt height ratio of 01.66. There appears to be a dependency of flame propagation on air flow rates and belt width, although the tests performed do not provide a quantitative trend. Recommendations are made for additional work to resolve some anomalous date and to fill voids in the rest program.

Jan 1, 1978

By E. E. Ungar

Criteria applicable to noise in coal cleaning plants are presented, and the generally applicable noise control principles and approaches are discussed. The operating characteristics and equipment of coal cleaning plants are described. Considerations entering in the selection and design of noise control means are delineated, and specific means for equipment noise reduction are described. The limited utility of acoustically absorptive materials in plant spaces is indicated, administrative means for reducing worker noise exposure are pointed out, and ear-protective devices are described briefly. The reduction of plant noise reaching nearby communities is discussed. Programs leading to quieter machines an coal cleaning plants are suggested.

Jan 1, 1974

By D. Randolph Berry

The United States Bureau of Mines (USBM) awarded a contract to Foster-Miller, Inc. to develop guidelines for the storage and use of Self-Contained Self-Rescuers (SCSRs) in underground non-coal mines. An SCSR is a device capable of supplying, in an emergency, one hour of self-contained oxygen (no breathing of mine air). The information and recommendations in this report were developed primarily from three sources: discussions with mine representatives (including management, labor, and government), site visits in underground mines I and a detailed analysis of every reported non-coal accident which produced d hazardous atmosphere during the 5-year period 1976-1980 -plus ten other major incidents from prior years. Volume IV has three major sections: Recommendations and Discussion (Section 2), Analysis of Mine Accidents (Appendix A), and a Summary of Discussions with Mine Representatives (Appendix B).

Jan 1, 1983

Collins Radio Company, through this contract with the Bureau of Mines, has conducted a System Study of Coal Mine Communi¬cations. The program was a three phase program to establish a data base, perform communication system analysis and optimi¬zation, and prepare equipment specifications to be included in this final report. At the start of establishing a data base both a knowledge of mine communication and coal mines in general was obtained. Communication system requirements and constraints were determined along with a survey of current and potential mine communication equipment. An investigation was completed concerning theoretical LF and VLF propagation characteristics, and UHF propagation tests were conducted in a working coal mine. Different mines were contacted and on-site surveys completed with respect to coal mine communication requirements.

Jan 1, 1973

By R. F. Chaiken

The Bureau of Mines has carried out experimental and theoretical studies with prilled and pulverized ammonium nitrate-fuel oil (AN-FO) mixtures containing varying amounts of fuel oil in an attempt to quantify the effects of stoichiometric composition, nonideal detonation behavior, and expansion volume on the production of CO, NO, and N02 fumes. Experimental fume measurements were obtained in the Bureau's large closed gallery facility (7.2 X 104 liter expansion chamber) and in the standard Crawshaw-Jones apparatus (90--liter expansion shamber) using a prepackaged charge configuration containing about 450 g of explosive.4 The theoretical calculation of toxic fumes was achieved with an equilibrium detonation code called "TIGER,," Contrary to initial expectations, the NOx (= NO + N02) fumes from the large gallery test were found to be in essential agreement with the Crawshaw-Jones results. It was also concluded that (1) "TIGER" calculations offer a good approach to the prediction of toxic fumes; (2) there is a basic problem in extrapolating laboratory measurements of CO fumes to mine conditions--this being due to postdetonation oxidation of CO to CO2; and (3) the detonation velocity decay rate of an explosive is a useful experimental parameter for correlating toxic fumes production with nonideal detonation behavior.

Jan 1, 1974

By James Gibbs

In order to provide an initial approach to the deposits of oil shale, nahcolite, and dawsonite in the central area or the Piceance Creek Basin in northwestern Colorado, the U.S.B.M. and associated contractor personnel drilled and cased a 96-inch ID shaft to a depth of 2,371 feet. The shaft was constructed using ?big hole? drilling techniques and succeeded in giving access to previously inaccessible deposits of the above minerals. This report documents the construction from its beginning in January 1977 to its completion in January 1978. Procedures used and problems encountered are discussed in detail.

Jan 1, 1978

By David D. Rabb

A report on location, sampling, assays, mineral examination, amenability leach tests, and evaluation of certain mine dumps in Mohave County, Arizona. Extractions of greater than 30 percent of the gold and silver were achieved during simulated heap leaching of selected mine dump material. Consumption of reagents was relatively low and results suggest leaching of prepared heaps is technically viable and could be economically attractive.

Jan 1, 1980

By R. Stefanko

This Final Report covers the work performed for Contract No. H0377043, "Cables for Face Equipment" from August 1, 1977 to April 1, 1981. It reports the findings in three areas of research: cable protection, circuit-breakers, and high-voltage cable couplers. Laboratory and analytical studies have been conducted in the three areas to determine proper circuit-breaker settings, cable sizes, and coupler performance. Also, an extensive field-monitoring program was established to relate in-mine epxerience to laboratory findings. Further, various pieces of equipment was designed for laboratory testing, particularly in the area of cable reeling and unreeling.

Jan 1, 1981

By John R. Rhodes

The objective of this project was to investigate the feasibility of analytical techniques potentially capable of determination of Mg, Al, Si, S, Ca and Fe in 1 to 2 mg samples of respirable coal mine dust, in a total analysis time of not more than 10 minutes per sample, using equipment capable of being truck mounted for field-laboratory operation. It was not essential that the technique be non-destructive, but the chosen technique is, and this enables the analysis to be performed directly on the 37 mm diameter membrane filter on which the respirable dust sample is normally collected. The sensitivity requirements are therefore quoted in terms of the units of measurement, µg/cm2. The detection limit (3o of the background criterion) should be 0.5 µg/cm2 or less. The precision should be 5% or better, at concentrations above which the detection limit is not the determining factor.

Jan 1, 1972

By G. R. Hopkins

[Apparent progress in fuel economy at petroleum refineries, as measured by the average amount of .seat units required to refine a barrel of crude oil, received a set-back in 1935, when the average rose to 562,00 B. t. u., compared with 562,000 B.t.u. in 1937 (see fig. l). The primary factor in the rise in average heat requirement's per barrel of crude oil refined in 1938 wan the decline in total runs to Invariably the average requirement increases when crude ins to stills decline, and vice versa. In other words, annual gains in fuel efficiency at refineries arc masked by the degree to which the capacity is utilized. Additional crude runs give lower average e heat requirements in two ways - first, because they are mane with the c expenditure of comparatively small amounts of auxiliary heat, and, second, because the additional runs generally represent simple topping operations. In 1938 crude runs, to stills declined 1.6 percent (from 1,183,440,000 barrels in 1937 to 1,165,015,000 barrels in 1938), but the total heat consumption declined only 0.4 percent, or from 663,866 billion B. t. u. in 1777 to 660, 56 billion in 1938 .]

Jan 1, 1939

By J. P. Powell

Records show that systematic water flooding was begun as early as 1935 in Greenwood County and in 1937 in Butler County. Water flooding on some earlier projects in Greenwood County were described in a Bureau of Mines Report of Investigation.2/ This report presents a discussion of 4 projects -2 in Butler County, 1 in Greenwood County, and 1 in Butler and Greenwood Counties. The location of these projects is shown in figure 1. The projects have been in operation 6 to 12 years and have recovered about 6.6 million barrels of additional oil from the injection of 84.7 million barrels of water. Three of the projects take advantage of the elevation of the nearby hilly terrain, and water from the treating ponds flows by gravity through the filters into the clear-water tanks. By utilizing gravity flow, fewer pumps and less electrical energy is required, resulting in more economical operation.

Jan 1, 1956

By G. R. Hopkins

The petroleum-refining industry established a new record in fuel efficiency at refineries in 1936, when 597,000 B. t. u. of heat were required to refine a barrel of crude oil, compared with an average of 615,000 B. t. u. in 1935 (see fig. 1). The principal factor in the "indicated gain in fuel efficiency at refineries in 1936 was an increase in crude runs of 11 percent over 1935. A large part of the heat utilized at refineries is consumed elsewhere than under stills, or in ways quite independent of crude-oil distillation. In other words, as the operating ratio (crude runs divided by capacity) for refineries increases toward the maximum of 100 percent, the fuel requirements show progressively smaller increases and the average E. t. u. consumption per barrel of crude refined declines.

Jan 1, 1938

By Robert L. Lagace, Michael A. Grossman, Alfred G. Emslie

This supplement to the final report is a collection of interim and monthly reports and working memoranda prepared during the course of this program to document the progress, methods and results of the work. The supplement is divided into the self-contained sections briefly described below. I. SELECTED MONTHLY TECHNICAL LETTER REPORTS - This section is a collection of selected monthly technical letter reports that briefly summarizes the chronological development of the analyses and results, including the different concepts, theoretical approaches, and methods of data reduction and analysis explored, and the discoveries, insights and findings made along the way. More detailed treatments of the key developments and results are presented in the interim reports and working memoranda reproduced in subsequent sections of this supplementary report, and in the separately published final report. II. BACKGROUND THEORY FOR MEASUREMENT PROGRAM ON MEDIUM AND HIGH FREQUENCY RADIO TRANSMISSION IN COAL SEAMS - Working Memorandum - This working memorandum gives the initial background theory needed to guide the planned measurements and data analyses of this program to describe the propagation of radio waves-in coal seams for the frequency range of 50 to 5000 kHz. III. MODELLING AND DATA ANALYSIS OF IN-MINE ELECTROMAGNETIC WAVE PROPAGATION - Interim Report - This interim report presents detailed treatments of the data analysis and modelling techniques used, and the associated results obtained from conductor-free area propagation data measured by T. Cory in the first set of six coal mines. The mines were located in three highcoal seams; the Pittsburgh seam in northern West Virginia, the Pocahontas No. 3 seam in Virginia, and the Herrin No. 6 seam in Illinois. IV. ANALYSIS OF MF PROPAGATION DATA FROM MARGARET NO. 11, NANTY GLO, EHRENFELD, AND ADRIAN COAL MINES - Interim Report - This interim report presents detailed treatments of several improved data analysis and Modelling methods applied to, and results obtained from, conductor-free area propagation data measured by T. Cory in the second set of four coal mines. These mines were located in three low-coal seams; the Upper Freeport seam in Pennsylvania and West Virginia and the Lower Freeport and Lower Kittaning seams in Pennsylvania. In addition, this report contains a reprint of two papers presented at a Bureau of Mines sponsored EM Guided Waves in Mine Environments Workshop held in Boulder Colorado. One paper describes the three-layer theoretical model and its application to the conductor-free data from the first six mines, while the second paper describes the theory developed for the coupling of loop antennas to a cable in a mine tunnel in a coal seam, and the model's application to data in the vicinity of cables taken at the Margaret No. 11 mine. V. A METHOD FOR NONINTRUSIVE, IN-SITU MEASUREMENT OF COAL AND ROCK CONDUCTIVITIES IN A COAL MINE TUNNEL - Working Memorandum - This working memorandum briefly describes a possible direct method, and its potential advantages and shortcomings, for performing in-situ measurements of coal and rock conductivities. VI. MODELLING AND DATA ANALYSIS OF IN-MINE ELECTROMAGNETIC WAVE PROPAGATION FROM 50 to 5000 kHz - Interim Report - This interim report presents a summary comparison of theoretical and experimental results for conductor- free areas in eleven coal mines located in seven coal seams. It also summarizes the findings and their implications for intrinsically-safe, portable radio communications between roving miners.

Jan 2, 1980

By Arnold O. Tanner

The recession that took hold of the domes-tic mining industry in 1981-82 finally abated somewhat in 1987, resulting from increases in many commodity prices, especially in the metals sector, and from continuing success in lowering operating costs. By no means was the work finished; the mining industry was in a sense entering a new era. The struggle for survival was still very evident for many companies and various commodities, but increasing productivity and profits were accompanied by indications that these trends were more long term than short term. Raw nonfuel minerals produced in the United States during 1987 had an estimated value of $26.3 billion, an increase of $2.9 billion over the 1986 value. This is the fifth consecutive year that the value has increased. Except for a decrease in 1982, the value each year has increased since 1971, or 15 of 16 years. The value of raw metals production increased by an estimated 28%, an impressive improvement since the drastic fall in 1982. Industrial minerals growth was comparatively flat, with an estimated in-crease in value of 0.1 %, continuing a trend of the previous 2 years. Metal mine production dropped considerably in 1982 and maintained its resultant lower level until 1987, when production significantly recovered.

Jan 1, 1989

By Lowell Stroud

Ten natural gases containing from 0.023 to 8.4 percent helium were investigated. In seven high-helium samples, the isotopic abundance of Ne21 was greater than in the atmosphere, being supplemented by 33 to 85 percent of "excess" or "radiogenic" Ne21. The ratio of He4/Ne21(rad) in these gases was evaluated and found to vary between 2.9 x 107 and 5.9 x 107 , a factor of approximately 2. Argon concentrations were determined by the isotope dilution method. The isotopic ratios of Ar40/Ar36 in the high-helium gases were from 5 to 75 times the atmospheric value, with the Ar40 being about 80 to 99 percent radiogenic in nature. The ratios of He4/Ar40(rad) in all 10 gases were evaluated and found to range from 4 to 18. The isotopic ratio of N14/N15 in four of the high-helium gases was essentially the same as in the atmosphere; in three cases it was approximately 5 percent higher than the atmospheric value of 272.0. The genesis of nitrogen and the relationship of nitrogen to helium in natural gases were reviewed and are discussed in terms of a theory for the concurrent generation of nitrogen, helium, radiogenic neon 21, and petroleum (hydrocarbon gases and liquids).

Jan 1, 1967

By V. F. Parry, W. S. Landers

"INTRODUCTION The primary object of this investigation was to determine changes in physical and chemical properties of subbituminous lump coal while in storage for 8 months in a typical residence and to demonstrate how this fuel may be stored without degradation or spontaneous combustion. The second object of the study was to determine how the stored coal performed in a hand-fired furnace operated under practical conditions.The investigation revealed that if care is exercised in placing sub-bituminous lump coal in a closed bin, no significant slacking or degrada¬tion occurs, no hazards arise, and over-all indicated efficiencies of about 65 to 69 percent can be obtained under practical,firing conditions that the average home owner can meet.Owing to the war emergency, much attention is being given to the proper storage of coal, and campaigns are being conducted to increase the quantity of coal being stored to relieve transportation and production overloads. Ordinarily, coal dealers do not recommend storage of subbituminous coal in homes owing to deterioration of the coal and to possible hazards from spontaneous combustion. This practice has grown from some troubles that have been experienced, which can be traced to improper preparation, improper bins, and poor technique in placing coal in a bin. There is no good reason why subbiturninous lump coal cannot be stored safely in homes."

Jun 1, 1944

By Kenneth L. Cashdollar

While underground coal technology has progressed over time, regulations on coal dust have not kept up ? the most recent rules are more than 80 years old. The National Institute for Occupational Safety and Health and the Mine Safety and Health Administration conducted a joint survey recently on coal particle ranges as measured in US coal mine samples. In underground coal mines, dust explosions are prevented by the addition of enough rock dust (usually limestone) to make the total dust mixture inert. The rock dust acts as a heat sink for the dispersed dust mixture by reducing the temperature below the value needed to propagate an explosion. Federal regulations require 65% in combustible content in intake airways and 80% incombustible content in return airways, where the coal dust is assumed to be finer in size. The regulations also require an additional 1% incombustible for each 0.1% methane in the ventilating air in intakes and 0.4% additional incombustible for each 0.1% methane in returns.

Jan 1, 2008

By S. H. Ash

THE MAGNITUDE of the drainage problem of the anthracite industry in Pennsylvania's Western Middle field is realized when it is known that in 1951 nine pumping plants in this field pumped nearly 36 billion gallons of water to the surface. This is almost 68,000 gallons per minute pumped against an average hydrostatic head of 350 feet for that year alone. In 1948 over 20,000 gallons per minute was pumped by relay pumps against an average hydrostatic head of 265 feet. In addition to the water pumped to the surface, it is estimated that 15,000 gallons per minute overflows to the surface from underground pools in idle mines. The volume (second-feet) of water pumped and overflow water is almost 1;z times the, average mean flow of the Schuylkill River at Pottsville for the 8-year period 1944--51 (7, 13).4 Mahanov and Shamokin Creeks drain an area of 99 square miles in the Western Middle field, and all surface drainage in this area must traverse some part, of the coal measures before entering these streams. On the basis of 46.03 inches of rainfall (the weighted average of 6 recording stations for 1948), the runoff from the drainage area during that period was 51 billion gallons, approximately 1 times the volume of water pumped by all mine-pumping plants in the Western Middle field. In other words, because of the pervious strata overlying the mine workings, approximately two-thirds of the total runoff in the drainage, area becomes mine water tributary to the pumping plants.

Jan 1, 1953