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By Carl Fisher

A microseismic roof fall warning system was field tested in Western and Eastern coal mines in the United States to better define the capabilities and limitations of the microseismic method in predicting roof fall Microseismic event and energy type data were obtained and documented for twenty-three coal mine roof falls. Field test results indicate that both the microseismic event and energy methods, as applied in this development effort, have a high probability for successful application in a commercially practical roof fall warning system. Based on the results and experience obtained during field testing, a commercial prototype microseismic roof fall warning system was designed and constructed. Although it was the intent of the program to field test the commercial prototype system, delays in equipment fabrication and contract time limitations did not permit field testing.

Jan 1, 1980

By Edward E. Johnson

The U.S. economy boomed in 1965, completing its fifth consecutive year of expansion. Although the advance was somewhat irregular, previous records for production, sales, employment, and income were topped. During the first few months of 1965, as the economy recovered from the depressing effects of the automobile strikes of late 1964, increases were unusually large. The gains moderated in early spring, but were stimulated at midyear by sharply rising capital outlays, excise tax cuts, in? creased Social Security payments, and accelerated Viet-Nam defense expenditures. Gross national product (GNP) in cur-rent dollars rose $49.5 billion or 7.8 percent, to a total of S681.2 billion. In constant dollars (effects of price changes eliminated), GNP increased 5.9 percent, a rate considerably higher than the historical postwar annual average growth of 3.5 per-cent. Demand increased in most final markets and was especially strong for business fixed investment and consumption expenditures. With the exception of construction, most of the increases in GNP were real, since prices increased less than 2 percent.

Jan 1, 1966

By W. N. Hoskins

This report covers the final results of a two-phase contract study conducted between July 1974 and October 1976. A comprehensive summary of the initial phase of the study is included. Phase I of the study involved the investigation and evaluation of all potential candidate underground systems for mining the deeper deposits of oil shale and associated minerals in the Piceance Creek basin of northwestern Colorado. Phase II called for the refinement and the detailed technical and economic analysis of the most promising system or systems, thus disclosed. Of the several systems initially investigated and evaluated, four Showed considerable merit for exploiting the deeper deposits: (1) chamber and pillar mining with spent shale backfill, (2) sublevel stoping with spent shale backfill, (3) sublevel stoping with full subsidence, and (4) block caving mining using LHD's. Final refinement and analysis of these four systems indicated their technical feasibility over at least part of the range of conditions expected in the deeper deposits. Their economic feasibility also was indicated under certain operating and market conditions. A variety of engineering, production, and cost information is provided on each of these systems.

Jan 1, 1976

By Allan J. Clark

This paper, describing the milling practice of the Homestake Mining Co., is one of a series being prepared by the Bureau of Mines. The author acknowledges the assistance of T. G. Chapman, one of the consulting engineers of the Bureau of Mines, in arranging this paper for publication.

Jan 1, 1931

By G. Stecklein

This report summarizes the results of research into the areas of the fragmentation and entrainment of Airborne Respirable Dust (ARD). The objectives of this program were four-fold: first, to review the present state of knowledge regarding ARD; second, to expand this state of knowledge through the identification of hypothetical microscopic mechanisms by which the coal is fragmented and the dust becomes entrained; third, to specify the informational requirements to verify or nullify these hypotheses; and fourth, to relate experimental techniques that will produce that required information. Additionally, insights are provided regarding potential methods of extraction and/or treatment which may reduce the concentration of ARD.

Jan 1, 1982

By Robert S. Sanford

The demand for aluminum for military use during World War II called for an expansion of aluminum production in the United States A large part of the bauxite (the normal ore of aluminum) consumed in this county comes from Netherlands Guiana, South America. During the war, enemy activities were at times a serious threat to the flow of bauxite to the United States. The need for aluminum. stimulated the investigation of domestic deposits of bauxite and emphasized the wisdom of studying other aluminous materials, such as high-alumina and diaspore clays, to determine their possible use as aluminum ores. The occurrence in Pennsylvania of high-alumina flint clays and nodular diaspore clays has been known for many years. Several companies are mining these high-alumina, low-iron (less than 3 percent Fe2O3) clays and using them for the manufacture of refractory brick. Most of the production has come from Clearfield County, but clay deposits arc known also in Cambria, Centre, Clarion, Clinton, Indiana, Jefferson, Somerset, and Westmoreland, Counties.

Jan 1, 1949

By M. D. Aldridge

This document reports the results of a two-year research effort aimed at improving communication systems used in coal mines. This work was conducted under a program whose original goal not only involved the development of practical and effective electronic systems for operational communications, but also for monitoring, at a central location, remote instruments at key positions in a mine. About half way through the originally proposed three year effort, the program was redirected to phase out the communication effort at the end of two years and to concentrate the program" resources on the investigation of new monitoring system concepts developed by this research. Thus, the work reported here is incomplete relative to the originally pro- posed program. However, the work was carried to the point of providing sufficient evidence to aid in the comparison of certain new communication concepts. For the concepts chosen for this study, the work was stopped short of hardware development and field testing, Several reports in the form of Master's theses and a Doctoral Dissertation have resulted from this research. They each report in considerable detail the results of several individual" contributions to this program. In preparing this report, an attempt has been made to provide a complete description of the significant results but with- out burdening the reader with the minute details. These more detailed reports are referenced heavily for the convenience of those interested. PRESENT COMMUNICATION METHODS Two types of communication systems are presently used In coal mines. They are: 1, Various forms of telephone systems, and 2. Carrier current radio systems using the trolley line as the interconnection circuit. Carrier current radio is used almost exclusively for control of rail trafflc by the dispatcher. Almost all other communication uses the telephone system, Telephone lines generally extend to areas where trolley lines are not present such as the outside offices and warehouse. Therefore the telephone system provides the primary means of voice communication. Telephones - Telephone systems employed in American coal mines fall into three categories. 1. Paging type telephone systems - these systems have individual stations which use battery powered transistor audio amplifiers to boost signal levels for normal communication. When in the page mode,

By K. P. Wang

SIGNIFICANT general developments took place in the Far East during 1964, with far-reaching repercussions on the mineral and industrial economies of individual countries and the region as a whole. Japan, during this, "the Year of the Open Door," ushered in the era of industrial maturity, greater independence in economic policy, and expanded technical assistance to less developed countries. Symbolic of its dynamic economic growth is the fact that Japan out-produced the Federal Republic of Germany in steel during 1964 to take over a third-ranking world position. Mainland China, recovering from the "Leap Forward" debacle, made significant gains in industrial output. Mainland Chinese trade with Japan was on the upswing, and discussions were held between the Chinese and the Soviets for possibly resuming Soviet aid in industrial and mineral development. Meanwhile, United States aid to Taiwan was being phased out because of progress achieved. Rapprochement between South Korea and Japan was imminent late in 1964, a factor which may well affect South Korean mineral development. The Indonesian-Malaysian confrontation created economic difficulties in both countries. The war in Viet-Nam seriously disrupted industrial activities, particularly in the south.

Jan 1, 1966

By Carl R. Peterson

This report describes the development and testing of a prototype tunneling machine. Principal efforts were aimed at testing of the fragmentation subsystem of a continuous drill and blast hard rock excavation machine suitable for use in underground mining and tunneling applications. The concept utilizes a unique self -shielding spiral blasting pattern that permits efficient performance with relatively small single shots, while at the same time directing major blast fragments at right angles to the tunnel axis. A major accomplishement was the development of a remote controlled, loading and initiation system in which explosive slurry and a detonator are Simultaneously placed (pumped) into the blasthole via a loading hose. The special electric long-delay detonator is inductively ignited upon emplacement, and the machine remains at the face during the blast.

Jan 1, 1976

By J. L. Wiley

THIS REVIEW contains abstracts of the technical literature and patents dealing with the history, development, and commercial application of the Bergius and related processes for the hydrogenation, under greater than atmospheric pressures, of liquid and solid carbonaceous materials such as coal, lignite, their distillation and extraction products, pitches and tars, and petroleum and its distillation residues. An attempt has been made to include abstracts of all the published information on this process and of as much of the captured foreign documents and reports compiled therefrom as could consistently be reviewed during the time allotted for the work. Contact with the current literature and patents and review of the foreign documents will be continued and the information will appear in Synthetic Liquid Fuels Abstracts, which is being issued bimonthly as a Bureau of Mines publication. The material in this review is divided in two sections-literature (part I) and patents (part II)-and each of these is arranged alphabetically by author or patentee with further chronological arrangement under each author or group of authors. Secondary authors and patentees as well as assignees are cross-indexed to the main entry. In serial articles or reports the complete series appears in the alphabetical arrangement according to the author of the first member of the series. Succeeding members as well as secondary authors are entered as cross references; Titles of the journals are used as the authors in anonymous references. By following such a procedure, an author index is not required. However, a detailed subject index and a numerical patent list by countries are given as part III.

Jan 1, 1950

By S. R. Zimmerley

Recent investigations of finely ground materials have verified Rittinger's law of crushing.4, This law states that the surface produced is proportional to the work expended in the crushing operation. Thus, for a unit of work applied to crushing quartz a definite amount of surface will be produced. Obviously, this amount of work applied to some other mineral will not produce equivalent surface. It follows that in an investigation of mill practice, where ore is being crashed, the relative crushing resistance of the component minerals must be known. In a previous investigation of the Rittinger law,5 the crashing resistance that is, the work required to produce a unit of surface - was accurately determined for quartz. The surface values were obtained by means of the rite of dissolution of quartz in hydrofluoric acid.6 If it were possible so to measure surface on other minerals the determination of relative crushing, resistance would be a simple matter; however, the results obtained on minerals other than quartz by a dissolution method were not encouraging. Moreover, if accurate values could be obtained by dissolution this method could probably never be used on a mixture of minerals such as occurs in an ore.

Jan 1, 1929

By C. F. Jackson

This paper has been prepared as a progress report in connection with the series of articles on mining methods and costs which are being published by the U. S. Bureau of Mines in the form of information circulars. When enough circulars have boon completed it is planned to publish a more complete and comprehensive paper in bulletin form dealing with the subject of underground transportation. Progress reports, followed b., bulletins, will be prepared from time to time dealing with other subjects included in the general study of mining methods at individual nines, such as mine development, drilling, and blasting; stoping methods (each principal stoping method to be summarized in a separate paper); Ventilation; wage, contract and bonus systems, etc.

Jan 1, 1931

By Edward G. Cunney

Track in underground bituminous coal mines was investigated, and technology was taken from other industries in order to obtain information on conditions that impair the safety and efficiency of the track and to develop guidelines and useful information on the construction, inspection and maintenance of mine track. Volume 1 contains information on the investigations, observed track conditions, useful technology from railroads and other industries, derivations of track condition descriptors and recommended limits, conclusions, and recommendations. Volume 2, Guidelines, contains recommended standards and practices for mine track. It includes the relation of track conditions to safe speeds; descriptions and limits for measurable track features such as gage; descriptions of conditions for track components that are normally not measurable, such as subbase soils; construction requirements and techniques, inspection requirements and methods; and methods for managing and performing track maintenance work. As a research product, it does not repeat the summary or derivations. Volume 3, Inspection Handbook, summarizes recommended standards and procedures from Volume 2 and provides related information for' ready reference by inspectors in the mines. As a research product to be used in mines, it does not repeat the summary, derivations or references.

Jan 1, 1977

By W. N. Hoskins

This report covers the final results of a two-phase contract study conducted between July 1974 and October 1976. A comprehensive summary of the initial phase of the study is included. Phase I of the study involved the investigation and evaluation of all potential candidate underground systems for mining the deeper deposits of oil shale and associated minerals in the Piceance Creek basin of northwestern Colorado. Phase II called for the refinement and the detailed technical and economic analysis of the most promising system, or systems, thus disclosed. Of the several systems initially investigated and evaluated, four showed considerable merit for exploiting the deeper deposits: (1) chamber and pillar mining with spent shale backfill, (2) sublevel stoping with spent shale backfill, (3) sublevel stoping with full subsidence, and (4) block caving mining using LHD's. Final refinement and analysis of these four systems indicated their technical feasibility over at least part of the range of conditions expected in the deeper deposits. Their economic feasibility also was indicated under certain operating and market conditions. A variety of engineering, production, and cost information is provided on each of these systems.

Jan 1, 1976

By R. E. Brewer

A critical review of the numerous test methods that have been devised for measuring the "plastic" and "swelling" properties of bituminous coking coals and the practical evaluation of the data obtained has long been needed. The author appreciates fully, first, the arduous problem of doing justice to the merits and limitations of the many original test methods and their manifold modifications and, second, the more difficult task of interpreting the test data obtained in their practical applications to the important problems involved in the coking process. It has been the constant aim of the author to point out the broader significance of the test principles employed in the different classes of test methods and the usefulness of the test data obtained in relation to the problem of coking bituminous coals, rather than to stimulate unduly a controversial criticism of the merits and limitations of any particular class of test methods or of individual test methods devised by different workers. The task has been quite difficult because of the almost total lack of accepted test standards and specifications.

Jan 1, 1942

This report briefly describes the broad program of research and technologic work conducted by the Bureau of Mines on coal and related subjects during 1966. In addition to n description of investigations on mining, preparation, and utilization of coal, an account is given of the Bureau's work in mine health and safety, coal resources, mine explosives, and environmental conditions relating to coal mining and utilization. Details of most of the projects are reported in publications cited throughout this report. Centers and laboratories conducting the coal research and related investigations appear in appendix A; organizations, institutions , and companies contributing to the Bureau's coal research and technologic program are listed in appendix B.

Jan 1, 1967

By P. L. Swanson, A. T. Iannacchione, W. J. Gale

This paper outlines the concepts used to correlate rock failure with microseismic events and presents examples of microseismic monitoring together with associated computer modelling of the rock failure. This study is motivated by the need to develop improved ways to reduce ground control hazards in underground mining. Toward this end we present and compare results from numerical modelling and micro- seismic monitoring studies conducted at several different mine sites. Emphasis is on integrating results obtained with these tools to characterize, and thus increase our understanding of, important mine deformation processes. The ultimate goal is to use this knowledge to design mine structures, and develop mitigation measures, that minimize specific ground control hazards.

Volume 2 presents the results of studies of Phelps Dodge Corporation's tailings embankments numbers 1West and 2 West, at Morenci, Ariz. The work involved compilation and description of pertinent factors relating to the physical features and operational characteristics of the facility, including information on embankment construction practices; investigation and research of the general geologic and seismicity characteristics of the site and vicinity; limited field exploration and materials sampling and testing at the site; installation and limited monitoring of piezometers, surface movement markers, and slope indicator casing; limited laboratory testing of materials to evaluate the basic index and engineering properties of the embankment and tailings materials; selected engineering analyses of the embankment for various types of potential "failure" conditions; and includes appendices.

Jan 1, 1974

By Richard L. Sayrs

The Eve Mills deposit is in Monroe County, Tenn., near the southeastern corner of the State. The deposit was examined in February 1943 by a Bureau of Mines engineer, and drilling the property was recommended to increase the on: reserves enough to justify mining should war needs require it. The deposits were explored, by 32 diamond-drill holes totaling 11,649 feet during the periods from July 1943 to November 7, 1945, and from April 1944 to August 17, 1944. The drilling campaign disclosed a large area of mineralization. The ore, however, is apparently confined to long, narrow sheets. The indicated grade of the ore bodies blocked cut by the Bureau of Mines is 4.o8 percent zinc and 2.10 percent iron.

Jan 1, 1949

By Graham W. Marks, Clyde A. Bridger

"INTRODUCTION An electrolytic process for the preparation of metallic cobalt has been developed recently in the Bureau of Mines Experimental Station at Boulder City, Nev. Chemical analysis shows this cobalt to contain impurities in small percentages, chief of which is nickel. It is desirable to be able to determine these impurities spectrographically. This report is concerned with a procedure for the spectrochemical determination of nickel in cobalt.Previous spectrographic work on cobalt was done by Breckpot and Mevis,/ who used the method of homologous pairs of lines. However, it was felt that a more detailed investigation was needed, employing the method of internal standards.ACKNOWLEDGMENTWe are indebted to B. G. Knickerbockor and his staff at the Boulder City, Nev., station of the Federal Bureau of Mines for their cooperation, and particularly to Richard W. Lewis and Robert G. Sanderson, who prepared nickel-free electrolytic cobalt for us."

Feb 1, 1948