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By D. P. Schlick

As of June 30, 1970, Federal regulations required the operator of each underground coal mine to maintain the average concentration of respirable dust below legislative standards. As of March 1, 1971, over 152,000 respirable dust samples have been processed by the Bureau of Mines. Approximately 75 percent of underground working sections are being sampled in accordance with Federal regulations. Results indicate that 72 percent of the sections which have completed at least one basic sampling cycle are below 3.0 mg/m3, the standard in effect under the Federal Coal Mine Health and Safety Act of 1969 (P.L. 91-173). Notices of Violation were issued on 1,670 underground mines for failure to begin a sampling program; Withdrawal Orders were issued in 64 of these instances. Notices of Violation were issued on 1,121 sections where applicable dust levels were exceeded; Withdrawal Orders were issued in seven of these instances. There are 381 mining sections currently operating on permit; from the interim Compliance Panel.

Jan 1, 1971

By N. A. Eilertsen

Procedures of mining high-calcium limestone underground at the Kimballton mine of the Standard Lime and Cement Co. in Giles County, west-central Virginia, are described. Drilling and blasting procedures area discussed in detail, and direct mining costs are tabulated in percentage of total cost. Output, about 1,725 tons of limestone a day, is attained with heavy trackless equipment by the room and pillar method of mining modified by benching floors. Operating features include underground air compression, electric-eye control of curtained doorways, use of a single jumbo drill rig for all drilling, and an effective plan for maintenance of equipment. The company's safety program has contributed to an outstanding safe mining record. The mine is integrated with a plant on the property which converts the stone to metallurgical and chemical grade lime.

Jan 1, 1964

By Everett A. Sondreal

Data are presented on the characteristics of lignites with emphasis on the composition and fusion properties of the ash. Differences in the analyses of commercial-grade lignites are related primarily to variations in moisture and ash contents. Lignite ash is generally characterized by high concentra¬tions of alkaline earth oxides and a greater tendency for retention of sulfur in the ash than higher-rank coals. Composition of ash varies significantly within and between mines. The differences within mines are significant for short distances and may be eliminated under certain circumstances by normal mixing occurring during mining. The sulfur in lignite averages 0.6 percent and is found primarily in the organic or pyritic forms with only a trace of the sulfate. During the stan¬dard laboratory asking procedures, from 60 to 100 percent of the original sul¬fur is retained in the lignite ash. Trace elements, such as uranium and germanium, in the ash from commercial¬-grade lignites are present in low concentrations, but others, primarily copper and silver, are present in specific samples in concentrations approaching those found in some commercial ores.

Jan 1, 1968

By Forrest T. Moyer

THE injury data and experience in this bulletin are presented in three general sections. The first section contains general and detailed data relating to 1948 injury experience in bituminous-coal and Pennsylvania anthracite mines, separately and combined into totals for all coal mines. The related employment, worktime, production, and productivity data are given in each breakdown of the statistical data. Tables 1 through 22 constitute a subsection and present statistics on number of injuries, frequency and severity rates, average severity, detailed and major causes of injuries, injury records of the coal-producing States, distribution of injuries by part of body, and distribution of injuries by days of disability. Tables 23 through 45, the second subsection, present injury experience in bituminous-coal mines by various selected factors of physical or operating conditions that ma contribute to the occurrence of injuries. The degree of mechanical loading, productivity, size of mine by number of men working and by tonnage mined, thickness of bed, length of shift, number of shifts, type of cap lamps, rating of mine as gassy or nongassy, type of ventilation, and combinations of these factors influencing mine safety are presented in this group of tables. Similar data on Pennsylvania anthracite mines are listed in tables 46 through 63, which comprise the third subsection. The second section of the report contains the generalized annual injury records of bituminous-coal, Pennsylvania anthracite, and all coal mines from the earliest available data through 1948. Tables 64 through 97 list the number of fatal and nonfatal injuries, injury rates, and causes of injuries on an industry basis, the long-term injury records of each coal-producing State, and the related employment, worktime, and production data.

Jan 1, 1952

By James R. Boyle

The mining methods and practices used at the Young zinc mine, American Zinc Co. of Tennessee, have resulted in a low-cost, high-yield operation. Zinc ore (sphalerite) occurs in limestone-dolomite beds of the Kingsport Formation and is mined by modified room and pillar method. Utilizing trackless mining equipment which incorporates a high degree of flexibility, this operation has had a steady increase in productivity.

Jan 1, 1965

By D. Harrington

The desirability of efficient control of air currents, and the necessity of supplying metal-mine workers with better and safer working conditions, has created an active interest in metal-mine ventilation, especially in recent years. This paper discusses the subject both with regard to efficiency and economy, as well as safety and health. It is based on personal observations of the writer from over four year's study of metal mines in six States, in which more than 50 mines were visited. Many of these were studied in detail; in all several thousand working places were examined, and readings taken relative to ventilation run into the tens of thousands.Object of ventilating metal mines:Whereas in coal mines ventilation is generally regarded as essential, in many metal mines, especially shallow ones, the operators pay little attention to ventilation, or ignore it altogether. Recent shortage of labor, and numerous accidents to which State compensation laws have directed attention, are causing metal-mine operators to regard ventilation more seriously, especially in deep, large mines.There is, in fact, greater necessity for adequate ventilation of metal mines than of coal mines. The latter require air currents to remove explosive gases and the fumes of explosives, but metal mines, in addition to the need of removing fumes of explosives, and occasionally explosive gases, frequently have need of removing dusts dangerous to health, reduction of high temperatures and high humidity, and removal of inert but unhealthful gases like CO2 and nitrugen. The generally accepted superior healthfulness of coal miners as compared with metal miners, is probably due in large part to the better air circulation in working places of coal mines.

Jun 1, 1920

By John F. McCoy

The U.S. Bureau of Mines (USBM) awarded? a contract to Foster-Miller, Inc. to develop guidelines for designing, constructing, stocking, and maintaining rescue chambers in underground mines. This report develops information and recommendations which could be used by a mine operator who desired to install a rescue chamber. Volume I covers the following major areas: atmospheric life support, configuration and construction, chamber location, power and lighting, equipment and supplies, communications, and psychological aspects and training. Volume II contains the following appendices: History of Barricading, Chamber Pressuriztion Considerations, Diffusional Infiltration of Gas, Compressed Air Storage, Location Examples, and Psychological Aspects.

Jan 1, 1983

By H. Tomlinson

This circular is one of a series of papers on coal mining methods and costs which being prepared by the United States Bureau of Mines for the purpose of making available to those interested in the industry a knowledge of the mining methods employed, the places here mechanical and hand loading are practiced, and coat data on the several operations pertaining to the removal of coal from the working faces and its transportation to the tipple for loading into railroad cars. Mining costs are governed by the relative efficiency of the mining method employed. The method is selected for Its adaptability to the local natural physical conditions such as the nature and thickness of the coal bed, its dip, the character of the coal, and the thickness of the overlying strata.

Jan 1, 1930

By Albert L. Toenges

This circular deals primarily with the various methods of longwall mining used in some mines in certain districts of the Middle Western States. In some instances underground methods were considered comprehensively, and in others only the actual methods of mining and face advance were noted. Results obtained by the mines in output per man were compared only on the basis of an operating day, since idle time and number of men employed would not, be comparable due to the great difference between mines in different districts. Man-hours per ton per operating day are noted in a general way. Material and power costs are not included. ACKNOWLEDGMENT The information used in preparing this paper was obtained through the courtesy and cooperation of the presidents and other officials of the comparnies operating the mines described. The approval of the executive of each property was obtained for publishing this manuscript, and the accuracy was checked.

Jan 1, 1936

By Ludwig Schmidt

Large quantities of gasoline are lost each year by evaporation from bulk-storage station tanks. The rate of evaporation from bulk-station tanks is influenced by two principal factors: First, the vapor pressure of the gasoline in the tank; and second, the amount of "breathing" of the tank. The vapor pressures of the gasoline govern the amount of the gasoline vapor in the air-vapor mixture above the gasoline in a tank at a given temperature. This is one of the principal factors in determining the total pressure of the air-vapor mixture within the tank. The "breathing" of the tank is caused by the inflow of air from the atmosphere during certain periods of the day and the expulsion of the air-vapor mixtures at other times, caused by atmospheric variations. The pressure built up within a tank and the amount of gasoline in the air-vapor mixture are both a direct function of the temperature existing within the tank. Therefore, two of the most common methods for reducing evaporation losses from bulk-station tanks are: (1) The use of vapor-tight tanks equipped with relief valves and operated at 1 or 2 ounces of pressure and about 1/2-ounce vacuum; (2) reducing the temperature of tanks and their contents by painting them a light color, by insulation, and in some instances by using water sprays. Water sprays, although effective, usually are too expensive to operate economically. In order to determine and compare the effects of various colors, insulation, and pressure in reducing the evaporation losses of gasoline held in storage in bulk-storage tanks, the Bureau of Mines made observations from May 29 to October 15. 1930, on five horizontal tanks of 12,000-gallon capacity each, which were erected at the plant of Black. Sivalls and Bryson Manufacturing Co., Kansas City, Mo. This report gives in detail the results of these evaporation tests.

Jan 1, 1931

By R. J. Leary

A small electronic digital computer employing punched cards has been used to facilitate the solution of a variety of problems in Bureau of Mines pyrometallurgical research. In this work the computer has been found to be economical for solving both simple problems that occur repeatedly and those involving complex or iterative calculations. Each of these classes of problems and their respective solutions are described. These small computers can be used effectively by researchers when they work in consultation with a computer specialist. Close team work produces the required solutions in less time, and, oftentimes, in a more useful form. Participation in programming by researchers develops in them a skill for evaluating the suitability of problems for electronic computing.

Jan 1, 1960

By W. J. Kroll

This report is concerned with the many sidelines that were investigated incidental to developing a process to produce ductile Zirconium by members of the staff of the Bureau of Mines laboratory, Albany, Oreg. The results of the main investigation, concerning the production of malleable zirconium by reduction of chloride with fused magnesium under helium, have been described in previous publications. These should be taken as a background to facilitate understanding of this work. Literature on the metallurgy of zirconium has been summarized in a separate publication (2), and references are given in this report only when new publications have to be considered or old ones stressed. Most of the observations described in this report can be applied to the problems involved in making titanium with virtually no change. In general, titanium is easier to reduce than zirconium, since its affinities are lower. Also, its chloride is easier to handle and keep clean because it is a liquid at room temperature.

Jan 1, 1952

By James R. Boyle

The mining methods and practices used at the Young zinc mine, American Zinc Co. of Tennessee, have resulted in a low-cost, high-yield operation. Zinc ore (sphalerite) occurs in limestone-dolomite beds of the Kingsport Formation and is mined by modified room and pillar method. Utilizing trackless mining equipment which incorporates a high degree of flexibility, this operation has had a steady increase in productivity.

Jan 1, 1965

By L. B. Berger, W. P. Yant, J. B. Littlefield

"INTRODUCTION Hydrogen sulphide (H2S) is one of the most toxic industrial gases and of relatively wide occurrence in industry. Among its common industrial occurrences are, in the production and refining of high-sulphur petroleum, in natural gases, in gypsum and sulphur mining, in rock strata and underground waters (where it is encountered in tunneling and caisson work) in blasting with black powder and in blasting high-sulphide ores with other explosives, in gas manufacture, in the carbonization of coal, and in the manufacture of chemicals.The usual methods of detection, other than by the sense of smell, which is lost in 2 to 15 minutes' exposure to 0.010. to 0.015 percent of this gas, 5/ either are too cumbersome for frequent and rapid analyses or, like the wet lead acetate paper test, afford only qualitative results. A qaantitative determination usually involves the use of solutions, bubblers, flowmeters, standard solutions, burettes, and indicators manipulated by trained technical men. All apparatus and methods in common laboratory use are, in general, unsuitable for the field.The physiological response attending exposure to various Concentrations of hydrogen sulphide in air, is as follows, in percent by volume 6/:0.005 to 0.010: Subacute poisoning - slight symptoms, such as mild conjunctivitis and respiratory-tract irritation after 1-hour exposure."

Jun 1, 1935

By M. C. Irani

This Bureau of Mines report tabulates methane emissions from U.S. bituminous coal mines with daily emission rates of at least 100,000 cfd according to States, counties, and coalbeds. Most of the methane emitted is from mines in the Appalachian States. Total daily emission in 1975 was 216.3 MMcfd, compared with 227.0 MMcfd in 1971 and 214.5 MMcfd in 1973. Thirty counties in nine States hid daily methane emissions of 1 MMcfd or more. These emitted 93 percent of the total methane. The highest emissions were from Monongalia County, W. Va., which accounted for 18.9 percent of the total. This was followed by Marion County, W. Va., 9.6 percent; Buchanan County, Va., 8.3 percent; Jefferson County, Ala., 6.1 percent; and Washington County, Pa., 5.9 percent. The Pittsburgh coalbed emitted 45.7 percent of the total methane, followed by the Pocahontas No. 3 coalbed with 12.9 percent. The report lists 196 mines, of which 60 had daily methane emissions of 1 MMcfd or more. Included in this compilation are the identification and thickness of the coalbed, methane emission, coal production and ventilation rates, number of drifts, shafts, and slopes used for ventilation purposes, shaft depth, age of mine, and gas-to-coal ratio.

Jan 1, 1977

By Oliver C. Ralston

Nonmetallic technologic investigations of the U. S. Bureau of Mines are headquartered at experiment stations in three widely separated localities of the United States. During 1936, the Nonmetals Division of the Technologic Branch was formally set up by combining the direction off the work of these three experiment stations under one administration. The New Brunswick (N.J.) station which in the past has been known as the Nonmetallic Minerals Experiment Station, is henceforth to be at College Park, Md., as part of the Eastern Experiment Station, and its principal activities will be related to the nonmetallic resources of the Eastern and New England States.

Jan 1, 1937

By Dennis J. Grigal

The objective of this contract was to monitor operating conditions of, four flooded, fibrous-bed filter panels used during normal underground mining operation and to analyse clogging and structural problems. After observing structural and clogging problems and conducting laboratory and field tests, a final, Flooded, fibrous-bed filter design which minimizes clogging and structural problems was recommended to the Bureau of Mines. This report also describes the dust sampling procedures used to determine the dust concentration at the flooded, fibrous-bed scrubber intake duct.

Jan 1, 1979

By D. Harrington

The record of fatalities from mine explosions in the United States during the fiscal years 1934 to 1937 wars the best in the history of the mining industry; that for the fiscal year 1939, however, is not so favorable, since nearly as many men (170) were killed by explosions in 1938 as were killed during all of the previous 4 years (182). In spite of the large increase in fatalities from explosions during 1938, the average for the past 5 year period (70.4) is less than one-half the average (13) of the preceding 5 year period. The reasons for the large increase in the number of explosion fatalities during the 7 past year as compared with the previous 4 year are not entirely clear; it is: evident, however, that in some instances there has been laxity in the enforcement of State minim laws, and also that come of our coal-mining people, including workers and operating officials, have failed to carry out tine known precautionary measures to prevent explosions.

Jan 1, 1939

By R. L. Bolmer

Rapid depletion of our known mineral resources has stimulated exploration for new mineral deposit. Abandoned mines or prospects may prove to be commercial in today's economy. Often it is necessary to revaluate such properties. Some of these may be inaccessible because of caving of flooding. Many, however, remain in good condition, except that over the years the air in the workings has become depleted of oxygen. Each year the Bureau of Mines receives numerous requests for aid in entering old mines, the air in which is incapable of supporting life. Requests of many individuals who wish to examine or explore-such places with the help, of the Bureau's self-contained oxygen breathing apparatus have been denied because of the hazards involved in the use of this equipment for such purposes. The distance to be traveled in irrespirable gases may be too great for safety; under favorable conditions, a round trip of 2,000 feet from fresh air is the maximum distance that may be traveled.3/ The use of such equipment is hazardous unless a team of at least 5 men thoroughly experienced in its use is provided; and when extensive traveling from. a fresh-air base is required, a reserve team should be provided.3/ Usually, the apparatus is requested for use in exploring workings having only one surface connection, as mines having more than one opening usually are more easily ventilated;,and in some natural ventilation is sufficient or can be made so by cleaning out obstructed openings.

Jan 1, 1951

By Frank Ruskey

This report describes a computer program devised by the Bureau of Mines to model coal-mining situations where one or more panels encounter oil or gas wells. The program seeks in several hundred trials to evade the wells if possible or to minimize their influence by shifting or skewing the mine plan and/or adjusting the centerline dimensions of the entryways. Upon completion of computations, the program sorts the hundreds of models which have been tested, and lists the 10 best with their associated parameters. It also draws a mine plan of the best configuration, showing the entryways and crosscuts along with the "lost" coal remaining in the barrier pillars surrounding the various wells.

Jan 1, 1972