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By Walter W. Kaufman

The braking performance of underground, rubber-tired, non-coal mining vehicles is evaluated. Surveys of mining equipment and braking manufacturers and underground stopping tests are discussed as they relate to this evaluation. Stopping performance recommendations are included as well as related aspects of roadway construction and runaway vehicle protective devices.

Jan 1, 1977

This report on the Venezuelan coal industry is the seventh in a series of studies on coal exporting countries requested by the House Appropriations Committee, The committee asked that the basic differences in mining costs for U.S, and foreign mines be identified, especially those costs incurred in complying with health, safety, and environmental regulations.1 Basic costs in extracting raw coal are analyzed in this report for surface operations, This report also provides a limited analysis of the relative market competitiveness of selected Venezuelan and U,S. steam coal mines in three electric utility markets: New England and the east coast of Florida in the United States, and western Europe. Although some Venezuelan coal has coking characteristics, all coal-producing regions of Venezuela sell coal in steam markets.

Jan 1, 1994

By E. D. Gardner

Placer mining is the mining and treatment of alluvial deposits for the recovery, of their valuable minerals. The method has been used principally for mining gold, but a large proportion of the world's production of tin, platinum, and diamonds and other gem stones and minor quantities of other heavy minerals have been won in this manner. In the United States, as in the world at large, gold has been the principal mineral obtained by placer mining. Minor quantities of metals of the platinum group are recovered with the gold in some localities. Important quantities of sapphires have been produced at placer mines in Montana, and tungsten minerals have been obtained on a commercial scale from placer deposits in California and Colorado. Other heavy minerals or gem stones, however, have not been mined to any important extent by this method in the United States. The search for placer gold and the working of the deposits when found have had much to do with the early development of the West. Placer mining has been gradually overtaken and surpassed in importance by lode-gold mining, until in 1932 less than a quarter of the country's total gold production was from placers or about an eighth, excluding Alaska. In 1932 about 76 percent of the placer gold produced in the United States was recovered by dredging. Although other forms of placer mining still are important, they have been declining for many years, as the richest and most readily mined deposits of gravel along the stream courses have been exhausted. During 1931 and 1932 there was a revival of small-scale mining, but few new deposits were discovered.

Jan 1, 1934

Helium has probably aroused more varied scientific curiosity than any other single element. Discovered by spectroscopic examination of the sun during an eclipse in 1868, helium is now known to exist not only in the sun and other stars but on earth occluded in minerals, accumulated with natural gases in pockets in the earth's crust, and in the atmosphere surrounding the earth. Astronomers study its presence in the various stars of the universe for clues to their origin and history. Geochemists and geologists study its occurrences in rocks, minerals, and meteorites to determine the age of the earth and the manner of its formation. Pathologists study its effect on living tissues in search for the ideal combination with oxygen for artificial breathing mixtures in medicine, diving operations, and space vehicles. Chemists study its physical properties and use it to trace the sequence of events in reactions in which it does not participate. Geneticists and bacteriologists use it for special studies. Physicists study its behavior when liquefied and the behavior of materials cooled to nearly absolute zero by its use. Nuclear physicists learn more about the universe through study of the nuclear reactions that produce it. Through study of helium and greater knowledge of its origin and properties, science continues to unlock some of nature's more closely guarded secrets. Unknown on earth before 1895, and not discovered as a minor constituent of natural gas until 1905, helium with its simple atomic structure--a nucleus with two electrons orbiting in a closed shell--is a unique element. It is next to the lightest gas, only hydrogen is lighter. It occupies position number 2 in the Periodic Table of the Elements and heads the list of so-called "rare" or ?noble? gases. Most of the naturally occurring helium has an atomic mass of 4.003874 (oxygen = 16). A trace (1.7 x 10-5 mol percent) is the light isotope helium-3 whose atomic mass is 3.0169800 Unstable isotopes of mass numbers 5 and 6 have been authenticated. Isotopes of mass numbers 7 and 8 have been reported, but their existence is less well established. All the heavier isotopes are radioactive and are the product of nuclear reactions.

Jan 1, 1968

By William H. Lesser

Never before have mine managers in the anthracite region of Pennsylvania been so seriously concerned about the rising cost of pumping mine water. Many of them know that future pumping charges may affect their operating profits adversely to an extent that will make it necessary to abandon some mines. Increased pumping charges in the anthracite industry are currently comparable in importance with higher mining costs; in fact, profitable operation of some mines depends not only upon the cost of mining coal but also upon whether they can be kept free from water at reasonable cost. Pumping charges are relatively low during the early development of a mine, but they increase rapidly as development progresses. Numerous crop falls, strippings, and. abandoned adjacent properties contribute unfavorably to the volume of water produced during mining. The foregoing conditions and the existence of large underground pools below existing mining levels present water problems of such magnitude and cost that some mine owners cannot continue to operate profitably.

Jan 1, 1950

By David E. Siskind

The U.S. Bureau of Mines and the State of Indiana cooperated with AMAX Coal Co. and its consultants to determine the effects of coal mine overburden blasting on nearby pipelines. Five pressurized 76-m pipeline sections were installed on the Minnehaha Mine highwall near Sullivan, IN, for testing to failure. Four 17-to 51-cm-diameter welded steel pipes and one 22-cm PVC pipe were monitored for vibration, strain, and pressure for a period of 6 months while production blasting advanced up to the test pipeline field. In contrast to previous studies of small-scale, close-in blasting for construction, these tests involved overburden blasts of up to 950 kg per delay in 31-cm blastholes. Analyses found low pipe responses, strains, and calculated stresses from even large blasts. Ground vibrations of 120 to 250 mm/s produced worst case strains that were about 25 pct of the strains resulting from normal pipeline operations and calculated stresses of only about 10 to 18 pct of the ultimate tensile strength. No pressurization failures or permanent strains occurred even at vibration amplitudes of 600 mm/s.

Jan 1, 2010

By W. R. Hardwick

This Information Circular describes the development of block-caving methods and practices by the Miami Copper Co. at the Miami mine in Gila County, Arizona. It is one of a series published by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. This report gives a history of the district and outlines early prospecting and exploration including methods of sampling and estimation of ore tonnage and value at the Miami mine. Early mining methods are described, particularly those that influenced developments in the caving method. Mine exploration, development, and operating methods for block caving are described with particular attention to those factors, physical, economic, engineering, and managerial that have improved efficiency in the mining operations over a long productive period. Extraction, ventilation, wage system, safety, water supply, power plant, and shop facilities are discussed. The last section gives a brief summary of such costs as are available for publication.

Jan 1, 1965

By W. R. Hardwick

This Information Circular describes the development of block-caving methods and practices by the Miami Copper Co. ar the Miami mine in Gila County, Arizona. It is one of a series published by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. This report gives a history of the district and outlines early prospecting and exploration including methods of sampling and estimation of ore tonnage and value at the Miami mine. Early mining methods are described, particularly those that influenced developments in the caving method. Mine exploration, development, and operating methods for block caving are described with particular attention to those factors, physical, economic, engineering, and managerial that have improved efficiency in the mining operations over a long productive period. Extraction, ventilation, wage system, safety, water supply, power plant, and shop facilities are discussed. The last section gives a brief summary of such costs as are available for publication.

Jan 1, 1965

By J. H. East

THE RIFLE, COLO., oil-shale project of the Bureau of Mines was a facet of the re-search and development activities conducted under the Synthetic Liquid Fuels Act (Public Law 78-290) of April 5, 1944. The principal objectives were to devise efficient methods to mine and retort oil shale and to refine shale oil into usable products, at a total cost low enough that shale oil could supplement the domestic supply of petroleum at competitive prices. The Rifle project included three major divisions: (1) Mining, (2) retorting, and (3) refining. The major functions of the mining program were to supply oil shale to the retorts, to devise mining procedures, and to develop an under-ground-mining method by which oil shale could be produced safely at an unusually low cost per ton. The selected mining procedures and direct mining costs were demonstrated by sustained test runs.

Jan 1, 1964

By J. A. Cooper

The objectives of this research were to define the chemical composition and physical characteristics of the aerosols associated with attached radon daughters in operating uranium mines, and to investigate the relationship between these aerosol parameters and operating conditions. Major Results and Conclusions The organic, inorganic and radiological characteristics of test chamber and active U-mine aerosols have been measured as a function of particle size. These measurements represent the first detailed analyses of the organic and inorganic components in U-mine aerosols and the first determinations of the details of the individual and total radon daughter distributions in operating U-mines. The following is a list of the major results and conclusions:

Jan 1, 2012

The objective of this handbook is to provide the inspector with guidance for recognizing hazards from inhalation contaminants in above ground work areas of underground and surface metal and nonmetal mining and processing facilities and evaluating these hazards by collecting samples or making field determinations and interpreting the analytical results. Portions of the handbook that should prove most useful to the inspectors include a survey check list, rules for determining if sampling is required, list of most frequently encountered contaminants, list of candidate contaminants and their sampling conditions, interpretation of results, and a procedure for a health and safety inspection.

Jan 1, 2011

"INTRODUCTION These inspection standards have been prepared for use as a guide for the Federal inspection of anthracite mines. They are a revision of ""Tentative Inspection Standards for Anthracite Mines,"" published as Bureau of Mines Information Circular 7231 in January 1943 and used as a guide for Federal inspections. Numerous changes in the original standards have been made, due in part to recognition of shortages of some types of safety equipment due to the war, in part to need of additional standards to cover certain mine conditions and practices, and in part to conditions not foreseen when the original standards were prepared.Throughout these standards reference is made to determining the methane content of the mine air by using a permissible flame safety lamp. The Bureau has approved various electrical devices for the detection of methane, but it is recognized that new devices for determining the percentage of combustible gases as well as the percentage of oxygen, might be perfected for general use in mines, and therefore it may be necessary to revise certain standards to include the use of such equipment if and when the device is accepted as being permissible.About one-fourth of these standards are marked with an asterisk (*) as being of particular importance in preventing accidents in many coal mines; however, failure to carry out the suggestions made in such of the other standards as are applicable may also lead to loss of life.With continuing change in mining methods, some of these standards may become inapplicable, and further revision will be advisable. Therefore, question regarding these standards and suggestions regarding new standards should be brought to the attention of the Bureau, so that changes may be made from time to time. Numerous changes proposed by mine operators and by State mining departments have been incorporated in these standards."

May 1, 1944

By M. S. Fleming

The objective was to evaluate central lubrication systems for potential use on underground mining equipment. Previous use on continuous mining equipment resulted in poor system performance because of improper selection of lubricants, component failures, and an inconsistent delivery of lubricant to the bearings. The principles and operational characteristics of systems are reviewed and evaluated, and it was concluded that systems are available which can provide reliable central lubrication if properly applied, installed, and maintained. The procedures for applying a system to a continuous miner are discussed. Investigation revealed the lack of significant information on lubrication-related equipment failures and injuries related to maintenance and repair operations, the lack of significant failure rate data for central lubrication system components, and the lack of performance standards for central lubrication systems and components. To continue the development of systems for underground mining equipment it is recommended that a data bank on failures and reliability for equipment with and without central lubrication systems be created, and standardized specifications and performance criteria be developed for central lubrication systems and components which will be used on underground mining equipment.

Jan 1, 1979

By Raymond B. Ladoo

Talc is a hydrous magnesium silicate having the chemical formula H2Mg3 (SiO8 ) 4 ; it is often called steatite, soapstone or potstorie, and by the trade names talc clay, agalite, asbestine, and verdolite. The term talc may be used to include all forms of the pure mineral, whereas steatite denotes particularly the massive, compact variety, and soapstone the impure, massive form that often contains only 50 per cent of talc. Merrill 1 says: The name soapstone is given to dark-gray and greenish talcose rocks, which are soft enough to be readily cut with a knife, and which have a pronounced soapy or greasy feeling; hence the name. Such rocks are commonly stated in textbooks to be compact forms .of steatite, or talc, but as the writer has elsewhere pointed out, and as shown by the analyses here given, few of them are even approximately pure forms of this mineral, but all contain varying proportions of chlorite, mica, and tremolite, together with perhaps unaltered residuals of pyroxene, granules of iron ore, iron pyrites, quartz, and, in seams and veins, calcite and magnesian carbonates. When pure, talc is soft, having a hardness of 1, but when impure or when it grades into its varieties, the hardness increases to 3 or 4. Talc ranges in color from pure white and silvery white through gray, green, apple green, gray green to dark green, nlso yellow, brown, or reddish when impure. It is rarely, if ever, found in wellformed crystals, but often occurs in foliated plates or in fibrous aggregates. It is commonly compact or massive or in fine granular aggregates. Several analyses of talc from different regions ·are given in Table 1. Talc has several varieties, the most important of which is Rensselaerite. This variety, found in a small area near Gouverneur, St. La.wrence County, N. Y., is a hard, fibrous, -waxlike mineral having the same chemical composition as talc, but lacking its softness and its peculiar greasy feel. Its hardness and its peculiar fibrous form, even when ground, have made its grinding and separation a separate problem. In addition to the varieties of talc and soapstone, the mineral pyrophyllite or agalmatolite, a hydrous silicate of alumina, with the formula H2Al2 (Si08 ), is also mined and sold as talc. It resembles talc in color, feel, luster, and structure, and may be successfully substituted for true talc for most uses. In this paper it will be considered as one of the commercial forms of talc.

Jan 1, 1923

A unity of viewpoint emerged from the workshop. The concept that transmission is via characteristic modes was a common theme in many of the presentations. Also, the confusion an the meaning of monofilar and bifilar to describe these dominant modes was cleared up. But, there was still a healthy divergence of opinion on what constitutes an optimum system. It was generally agreed that further analytical and experimental work is definitely needed. In particular, it was stressed that independent measurements of the constitutive properties of the electromagnetic environment are needed. Also, there was considerable concern that laboratory measurements of rock samples could lead to misleading results for the effective conductivities. Also, there was a general recognition that over simplified propagation theory should not be used to interpret field data. From a theoratical and practical point of view, it was realized that mode coupling plays a vital role in the transmission channel. One must not only understand which and how many propagation modes are excited by the transmitting antenna, but the conversion of energy from one mode type to another must be accounted for. This conversion can either be done intentionally (by fixed mode convertors) or non intentionally (by random wall roughness). In fact, mode conversion can be quite complicated when various propagation paths exist such as when insulated cables, leaky feeders, grounded rails, coal seams, etc. all convey portions of the electromagnetic energy. However, this state of affairs should be regared as an. opportunity for extended communication coverage in mines rather than a limitation of a desig. procedure based on preconceived notions of the dominant propagation mechanism.

Jan 1, 1978

By Robert H. Peters

This U.S. Bureau of Mines report identifies the types of serious accidents that occur most frequently at small underground coal mines and describes the strategies that could help prevent these accidents. A wide variety of methods for improving safety are suggested, including improvements in the design of equipment, work procedures, work schedules, safety programs, and emergency response plans, as well as techniques for diagnosing the potential hazards associated with new technologies and work procedures. Some of the papers in this volume focus on preventing specific types of mining accidents--ones associated with materials handling (primarily back injuries), equipment maintenance, improper machine guarding, and ground failure during retreat mining. Although the recommendations in this volume are heavily influenced by research performed at underground coal mines in the Appalachian coalfields, most of the papers contain advice that is equally pertinent to almost any type of mine.

Jan 1, 1994

By Andrew B. Cecala

The U.S. Bureau of Mines has designed and evaluated total mill ventilation systems at two different mineral processing operations. Both systems have proven very effective at reducing respirable dust levels throughout the mill in a cost-effective manner. A 25,500-cfm system installed at a clay processing mill provided approximately 10 air changes per hour. This system reduced respirable dust concentrations by approximately 40 pct throughout the mill building. The second evaluation was performed at a silica sand operation. Tests were performed with 50,000 and 100,000 cfm of ventilation to the mill building, corresponding to 17 and 34 air changes per hour. Average mill-wide respirable dust reductions were 36 and 64 pct, respectively. Not only did these systems reduce respirable dust concentrations and increase visibility throughout the mills, they were also easy to install and required minimal maintenance. A total mill ventilation system provides a general purging of the mill air; the system should be viewed as a supplemental technique to assist other dust control systems in operation.

Jan 1, 2010

By Ruth F. Brinkley

Principle activities of the Bureau of Mines Explosives Research Laboratory from July 1, 1960 to June 30, 1961 are reviewed briefly in Part 1. Part 1 also includes data obtained in connection with several minor investigations which are not sufficient to warrant separate publications. Part 2 gives brief abstracts of publications that appeared during fiscal year 1961; in general, the research reported in these publications antedates this period.

Jan 1, 1963

By A. N. Baldwin

This report documents work performed under Bureau of Mines Contract J0265029 to study and develop two innovative mining systems: ? An underground auger capable of augering into the right and left ribs without repositioning the machine ? A conventional mining system employing recently developed innovative machinery. The report is separated into two volumes to document the two studies separately. Volume I describes work performed and the recommended concept for a bidirectional auger. Volume II describes the studies of mining equipment performance and mining plane developed to determine a conventional mining plan offering improved productivity.

Jan 1, 1977

By W. R. Hardwick

This Information Circular describes the development of block-caving methods and practices by the Miami Copper Co. at the Miami mine in Gila County, Arizona. It is one of a series published by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. This report gives a history of the district and outlines early prospecting and exploration including methods of sampling and estimation of ore tonnage and value at the Miami mine. Early mining methods are described, particularly those that influenced developments in the caving method. Mine exploration, development, and operating methods for block caving are described with particular attention to those factors, physical, economic, engineering, and managerial that have improved efficiency in the mining operations over a long productive period. Extraction, ventilation, wage system, safety, water supply, power plant, and shop facilities are discussed. The last section gives a brief sumary of such costs as are available for publication.

Dec 1, 1964