Search Documents

By Carl R. Christiansen

The primary objectives of this project are (1) the determination of manpower demand in primary lead and zinc production for the years 1985 and 2000, and (2) the estimation of the availability of the required manpower for these years. In order to meet the first of these objectives relationships between employee requirements and metal production in the various states were established, The total primary lead and zinc production from United states mines in 1985 and 2000 has been predicted by the U.S. Bureau of Mines. These forecasts and the 1974 figures are as follows: [1974 1985 2000 Lead metal, tons 669,000 700,000 900,000 Zinc metal, tons 494,000 585,000 995,000] Mining By analysis of ore reserve data and industry characteristics, the authors estimated the portion of the primary production which each state would yield in the future years. As manpower requirements are determined by the tons of ore produced and by worker productivity, these figures were determined for each mining state and district by developing relationships between lead and zinc metal production, ore production, ore to recoverable metal ratios, employee productivity, and number of employees required. The number of new employees required annually to compensate for attrition and production growth is provided, also.

Jan 1, 1975

By E. H. Denny

The presence in the Cripple Creek district, Colo., of irrespirable gas or gases, generally known to consist mainly of nitrogen and carbon dioxide, has been recognized by members of the mining industry in that region almost since underground mining was begun there; the occurrence, origin, and possible control of these gases have been discussed in several articles cited at various places in this report. Similar gases have also been studied in other metal-mining districts, as later discussed. In March, 1925, there were two fatalities from rock-strata gases in the shaft of the Index mine, near Cripple Creek. Two men repairing the bell or signal line preparatory to reopening the shaft were lowered into irrespirable gases and died. Their bodies were recovered by rescue crews from the United States Bureau of Mines and .the Portland mine, Victor, Colo. These crews found it necessary to use oxygen breathing apparatus. In October of the same year a miner was trapped on the 6 level of the Midget mine by an influx of gases that filled the shaft to a point above that where he was working. Oxygen breathing apparatus was again used by Bureau of Mines employees, who were in the vicinity, and the man was brought out in time to save his life. These two fatalities and one near fatality seemed to show that additional investigation of the gases and methods of control might be warranted. Accordingly, field and laboratory studies were begun by the authors of this report after a visit to the district by M. van Siclen, then engineer in charge, mining research division, Bureau of Mines, and after conferences with the Mine Owners' Association of Cripple Creek and with J. T. Joyce, metal-mine commissioner of the State of Colorado. The mine operators of the Cripple Creek district and the State mine commissioner's office gave whole-hearted cooperation in this work.

Jan 1, 1930

By William C. Cooley

[ ]

Jan 1, 1975

By James Westfield

A brief résumé follows of recent activities of the Division of Coal-Mine Inspection that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code for Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous-coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reporting to the Coal Mines Administrator any violations of the Federal Mine Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority (under Executive Order 9728) was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1958

By Charles J. Haas

The objective of this research was to investigate the interaction phenomena of rock and types of rock bolts to develop design principals for using grouted roof bolts. The investigation was to determine the effectiveness of grouted bolts in resisting lateral displacement and axial separation along fracture planes, and also to determine if grouted bolts eliminate the axial tensile stress near the anchor and the resulting rock fracture. The first year's effort involved defining the post-tensioning response of grouted bars and determining the amount of shear resistance generated by conventional and resin-grouted bolts. A finite-element analysis showed that if the rock and resin grout behave in an elastic manner, the post tensioning of a grouted bar will affect mine roof stability only if movement occurs near the collar. An experimental shear test program revealed that both conventional bolts and resin-grouted reinforcing bars significantly increase shear resistance along fracture or bedding plane when the average normal compressive stress on that plane is low (in the order of 25 psi) and when the bolt is oriented so that the shear displacement tends to lengthen the bolt. An increase in shear resistance is also noted at the higher normal pressure of 250 psi; however, the increase is small compared to the corresponding shear resistance without a bolt. Conventional bolts oriented so that they tended to loosen with shear displacement added no significant shear resistance.

Jan 1, 1974

By G. B. Sonneman

This final report summarizes the work done by The Bendix Corporation, Environmental Science Division, under contract to the Bureau of Mines to design, develop and test two improved systems for remote sampling the air at the working face of a coal mine in conjunction with approved portable methane detectors and machine-mounted methane monitors respectively. The work was started in May 1973 with preliminary design studies and was completed in May 1975. Five portable and two machine-mounted sampling systems were delivered. Contract "add-on" requirements for (1) modification of the machine-mounted system to accommodate a flame safety lamp and (2) a study of sensor response time improvement for the machine-mounted system were also completed.

Jan 1, 1975

By A. U. Miller

Since coal -mining records have been kept , reports of all mining States show that each year the lives of many workers have been sacrificed in the production of coal , and Illinois has contributed its share , Illinois reports for the 50 years 1882 to 1932 , inclusive , show that 6,673 men were killed -- 6,121 underground , 340 in the shaft , and 212 on the surface . Of the fatalities underground , 3,116 were caused by falls of roof or sides , 1,111 by haulage , 630 by explosives , 577 by gas explosions , 139 by electricity, and 548 by other causes ; 166 of the shaft fatalities were caused by falling down the shaft , 143 by the cage , and 31 by other causes ; 108 of the surface fatalities were caused by railroad cars , 46 by machinery , and 58 by other causes . Most of those engaged in mining are still of the opinion that it is an extremely hazardous occupation and that it is practically impossible to operate without accidents ; however , students of safety in mining now believe that with the proper attention to accident prevention mining may be conducted with little , if any , greater accident rate than that of other supposedly hazardous industries . There is no mystery connected with accidents in mining ; reports show that the majority are due to two main causes , falls of roof and sides and haulage . Mining companies in Illinois , as well as in other States , have proved in the past few years that the hazards of mining , like those of other industries , can be controlled to a large extent and the mines operated with few if any accidents , provided a great enough effort is made by employer and worker . Although the past accident rate of Illinois may compare favorably with that of other mining States it is higher than it should be ; the fact that 6,673 men (an average of 133.46 per year) were killed in and around the mines of the State between 1882- and 1932 indicates that accident prevention should receive more consideration in the future than in the past .

Nov 1, 1934

By T. F. Curry, L. B. Berger, H. A. Watson, S. J. Pearce

The conduct of work at elevated air pressures , such as in caissons and in tunnel - driving in subaqueous strata , poses safety problems not encountered in mining and tunneling operations at ordinary atmospheric pressure . This publication discusses some of the problems involved and presents information on the following subjects : ( 1 ) Physiological effects of gases at elevated pressure . ( 2 ) Use of respiratory protective equipment in rescue or recovery operations in event of fire or other emergency in pressurized tunnels . ( 3 ) Effect of elevated pressure on performance of some gasdetecting instruments ; interpretation of the results . Various types of respiratory protective devices are discussed in relation to their possible use at elevated pressures , especially the 2 - hour , selfcontained , recirculating - oxygen - breathing apparatus , which has had wide use in the United States during rescue and recovery work in the mining industry . A modified procedure that eliminates the hazard of oxygen poisoning enabling the safe use of this apparatus at elevated pressures , up to 45 pounds per square inch , gage , and tests to verify its practicability are described . procedure involves control of the partial pressure of oxygen in the breathing

Jan 1, 1964

By John E. Lambert

Automatic control of drum head continuous mining machines was investigated as a means of reducing respirable dust generated and operator variabitity. Literature survey, manufacturer interviews and mine visits were the major information sources. Technically feasible automation concepts were Identified to control sump and shear rates, cutter head elevation limits and sumping distance. These are the elements of a programmed cutting cycle which maintains peak penetrating force on the cutter, to maximize depth of cut and therefore reduce dust generation. Based on the industry surveys, successful underground hardware demonstrations must be completed in order to stimulate the market demand for these advanced control features.

Jan 1, 1979

By Robert H. Ridgway

This circular outlines salient facts regarding the sulphur industry of the United States and the world. It is founded chiefly upon published information available in the literature of the subject. The Bureau of Mines has in its files additional, more detailed data upon many of the topics presented very briefly here, and will endeavor to assist the mineral industries and the public by giving further information in response to individual inquiries. It will welcome comments, criticisms, and contributions of data that may assist in making later editions of this circular more accurate, or in developing more fully the bureau's mineral files pertaining to sulphur. Throughout this paper sulphur is used to designate crude sulphur or brimstone, not sulphur produced from pyrites or' smelter gases.

Jan 1, 1930

By R. J. Fantel

The Bureau of Mines investigated the resource availability of titanium minerals from 63 mines and deposits in 12 market economy countries. These mines and deposits contain, at the demonstrated resource level, an estimated 438 million metric tons (mt) of titanium dioxide (TiO2) in the minerals rutile, ilmenite, leucoxene, and anatase. An additional 314 million mt of TiOz is available from inferred resources. If all titanium minerals and other recovered heavy minerals are sold at total costs at least equal to the January 1984 market prices, approximately 200 million mt of contained TiO2 could be recovered in total. In terms of mineral concentrates, this equals approximately 11 million mt of rutile concentrate, 187 million mt of ilmenite concentrate, 3 million mt of leucoxene concentrate, 13 million mt of synthetic rutile concentrate (in addition to the ilmenite), and 89 million mt of titanium slag. The study indicates that world resources of low-cost rutile are declining. In order to maintain future supply for high-grade titanium resources, alternate sources will need to be developed, which may include higher cost rutile mines, Brazilian anatase deposits, increased production from slag operations, or more synthetic rutile capacity from ilmenite resources, which are abundant.

Jan 1, 1986

By George Watkin Evans

The United States Geological Survey has estimated 1 that the State of Washington contains 11,412,000,000 tons of bituminous coal and 52,442,000,000 tons of subbituminous coal, in beds more than 14 inches thick. As the present rate of production is about 4,000,000 tons a year, Washington apparently contains coal enough to supply Pacific coast markets for many years. The character of the coal beds of Washington renders the production of clean coal very difficult, and a considerable proportion of the output is washed before it is marketed. In 1915 Washington ranked fifth among the States in the amount of coal washed, though only twentieth in total output. In that year 37.9 per cent of the coal produced in the State was treated in surface cleaning plants.

Jan 1, 1924

By Harmon E. Keyes

Many organizations, including the Bureau of Mines, have made intensive studies of the application of leaching methods to relatively small low-grade disseminated deposits of copper ores, containing both oxide and sulphide minerals. One of the principal difficulties has been to obtain a solvent that could be made at a low cost and would effectively dissolve the copper minerals. Another drawback has been the high initial cost of a plant and the refined type of mechanism ordinarily required by standard practice for carrying out the leaching cycle. The Bureau of Mines has attempted to develop a cheap and efficient solvent that would especially meet the requirements of smaller plants. (See Bibliography.) It has been known that dilute ferric sulphate-sulphuric acid solution is an excellent solvent for most copper minerals, such as chalcocite, bornite, and oxidized forms, but not for chalcopyrite and certain silicates. A method of producing this solution from sulphurous products and waste liquors was developed by the bureau and tried successfully on a test-plant scale at the Southwest Experiment Station in cooperation with the department of mining and metallurgy, University of Arizona, Tucson, Ariz. However, this work did not involve the actual leaching of ores with the solutions thus produced or the cyclic use of the iron solutions in the regenerator cell. Except for certain laboratory tests, in which known impurities were added, no data were available to show the effect on regeneration if accumulations of impurities were built up in the leaching circuit.

Jan 1, 1930

By R. G. Warncke, D. Harrington

"INTRODUCTION The use of black blasting powder as an explosive in coal mines has long been recognized as hazardous and has been responsible for many of the worst disasters in American coal mines. One of the most pressing of the numerous problems confronting the Bureau of Mines, upon its creation in 1910 was to determine methods that would lessen the hazards created by the use of explosives in coal mines. The Bureau continued the study begun by the Technologic Branch of the Geological Survey as to the nature of explosives and made numerous tests to determine types of explosives suitable for blasting in coal mines. The Bureau has tested and approved hundreds of types of explosives and has disseminated information on methods and conditions for use underground to make them permissible as to safety. The Bureau of Mines has encouraged the use of permissible explosives for coal-mine blasting, and its experts both in the laboratory and in the field believe that the use of black blasting powder in any form (granular or pellet) is hazardous in any underground coal mine. Despite the information published at various times and innumerous ways and the general knowledge of the hazards that the use of black blasting powder in any form creates in the blasting of coal, the coal mines in the United States, during 1947 used approximately 34 million pounds of black blasting powder (granular or pellet), or approximately 11.8 percent of the total quantity of explosives used by the coal-mining industry.Many coal mines of the United States, for various and sundry reasons, probably will continue the use of black blasting powder, and this circular has been written for the benefit of such users, not that any suggested method or methods will make the use of this explosive safe, but it has been found that methods and conditions of use of black blasting powder can be improved so as to lessen, though not eliminate, the hazards created by its use."

Mar 1, 1949

By Joan Weinberg

Real gross national produce (GNP) grew at a seasonally adjusted annual rate of 2.0% in the fourth quarter (table 1). The restrained quarterly growth rate was the slowest in 2 years, and was substantially slower than the 2.5 % rate of the previous quarter. According to the U.S. Department of Commerce, the summer drought reduced the fourth-quarter growth rate by 1.1 percentage points. A growing trade deficit and a reduction in business investment were the key economic factors curtailing growth. The trade deficit widened by $6.8 billion, reflecting both a surge of imports and a slowing of exports. Business investment declined 3.7%, mainly as a result of a slowdown in computer sales. On a year-to-year basis, the economy grew at an inflation-adjusted rate of 3.8% for 1988, the fastest in 4 years, despite the drought. However, on a fourth-quarter-to-fourth-quarter basis, real growth measured 2.7%. Increased exports and business spending for plant and equipment accounted for much of the 1988 GNP growth. Employment continued to grow as the manufacturing sector added 414,000 new workers (table 2). Of these, the primary metals industry added 26,000 workers, and the clay, glass, and stone industry added 10,000. The civilian unemployment rate remained low throughout 1988, fluctuating between 5.3% and 5.4% during the last quarter.

Jan 1, 1989

By R. W. Fatzinger

The accident-frequency rate for placer mining in 1942 is reported as 36.923 accidents per million man-hours worked. This figure places placer-mining accident frequency slightly higher than that given for quarrying-35.7-but considerably under the 78.0 for coal mining and 56.5 for metal mining.4 Placer mining is subdivided into four types of activity: Underground, surface, dredging, and hydraulicking. It is the purpose of this paper to present and discuss safety practices in dredging and hydraulic mining; therefore, the following considerations will be limited to these two types of placer mining.

Jan 1, 1948

By Cloyd M. Smith

Progressive mine management is placing increased emphasis on improved ventilation as a contribution to better safety , health , and productivity of miners . Management is on the alert for means of bettering the working environment by increasing the flow of air and distributing it more effectively to the working places , having in mind the necessity of avoiding exorbitant ventilation costs . A basic need in planning betterments of this kind is knowledge of existing rates of flow and air pressures , infCoorrmmaattiicon that is supplied through ventilation surveys . Some companies make partial surveys from time to time , but few make complete surveys on a routine basis . This report describes the practice of a large British anthracite -mining company , which operates 24 collieries in South Wales , in carrying out a routine program of ventilation surveying . Ventilation characteristics and climatic conditions in the working places of its collieries are determined at frequent intervals with a view to increasing the effectiveness of ventilation and protecting the health of workers . It is thought that many of the points of the procedure used in making the surveys and in compiling and reporting the results will be applicable to American practice and that a discussion of the program may be helpful to colliery managers who are planning similar work .

Oct 1, 1949

This volume constitutes the final report for the Rescue Subsystem portion of the Coal Mine Rescue and Survival System program conducted by the Westinghouse Electric Corporation under contract to the United States Bureau of Mines (Contract Number H0101262 dated Jung 17, 1970). The program was directed by the Special Systems Department of the Westinghouse, Baltimore, Maryland facility. The basic objectives of the CMRSS program were to develop and test hardware to determine the efficacy of a variety of coal mine rescue and survival concepts and techniques. These concepts were drawn from two major- sources: the Request for Proposal from the Bureau of Mines and the final report on the Mine Rescue and Survival Study conducted by the National Academy of Engineering (NAE).

Jan 1, 1971

By Morton Corn

The U. S. Federal Coal Mine Health and Safety Act of 1969 placed limits on the permissible concentration of airborne respirable coal mine dust. Evidence exists which suggests that the effects on health of respirable coal mine dust may depend on both host factors and dust properties other than concentration. Dust particle size, shape, density, specific surface area and chemical composition are among the dust parameters of interest in an epidemiological investigation of coal workers' pneumoconiosis and coal miner exposure to mine dust. The purpose of this investigation was to develop and demonstrate the feasibility of techniques to determine selected properties of respirable coal mine dust. An approved underground horizontal elutriator which samples air at 36 cfm was designed, fabricated and utilized in this study to collect respirable coal mine dust in three mines representing the Pittsburgh, Lower Freeport and Lower Kittanning coal seams. Analytical procedures for measurement of respirable dust sample particle size, density, random projected area, total surface area and chemical composition are presented. Results of analyses of three samples collected in each mine are presented. Up to five full work shifts of sampling were required to accumulate approximately five grams of respirable coal mine dust in each sample. Statistical tests were applied to determine the significance of differences between properties of dust samples collected in the same mine and between arithmetic mean values of dust properties representing three samples collected in each mine. A comparison was also made between

Jan 1, 1972

By F. S. LOTT

The number of petroleum refineries in the United States decreased from 399 on January 1, 1947, to 390 on January 1, 1948. On the latter date two additional refineries were under construction , a large one in New Jersey and a small one in Texas . This Crude oil charging capacity, based on complete facilities only , increased in 1947 from 5,569,482 barrels to 6,034,252 barrels per day , owing to material gains reported in all of the larger refining districts . great increase in effective capacity is only in part the result of the completion of major new units for crude-oil processing . Much of it is due to rearrangement and minor additions to existing facilities to permit more efficient and complete utilization . Recent experience has apparently demonstrated that many processing units are capable , with greater emphasis upon maintenance and precise controls , of sustained operations at higher volumes than were indicated in their old rated capacities . This situation doubtless has caused some upward revision in capacity data .

Aug 1, 1948