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By R. W. Stahl

An emergency is defined as an unforeseen combination of circumstances that calls for immediate action. When applied to a coal mine, an emergency may call for prompt removal of the men to the surface through travelways other than the haulageway or intake airways, which are generally contaminated with irrespirable air as a result of an explosion or fire. Therefore, maintenance of adequate and travelable escapeways from all working areas of a mine is vitally important insurance against disaster. Several mine disasters could have been avoided if well-defined escape routes had been provided and made known to all mine employees. Such occurrences, unnecessary as they generally are, unfairly indict the industry when only a small segment thereof is involved. As a result of a rather recent disaster, which might not have happened if good escape routes had been provided, the Bureau of Mines decided to delve into the escape procedure to determine (1) what is being done in the industry and (2) what might be done at reasonable cost.

Jan 1, 1962

By Todd M. Ruff

Researchers at the National Institute for Occupational Safety and Health (NIOSH), Spokane Research Laboratory, are investigating technology and methods to monitor the blind areas around large haulage equipment used in surface mines. On average, six fatalities a year can be attributed to equipment colliding with other vehicles or pedestrian workers, or backing over the edge of a dump point. Several off-the-shelf technologies exist for monitoring areas that an equipment operator cannot see from the cab, including radar, video cameras, and radio signal detection systems. NIOSH researchers have tested many of these systems on large dump trucks both at their test facility and at surface mines. This article discusses the technologies available for this application and their effectiveness in detecting objects near an off-highway dump truck. Also, guidance is presented for mine safety personnel who are planning to evaluate collision warning systems or cameras on their haulage equipment. Available Technology Over the past few years, the number and types of systems available for monitoring the blind areas around heavy equipment have increased. Systems marketed for the automotive and recreational vehicle industries have been around for a while. Small video cameras can be found

In July 1982 the Committee on Underground Coal Mine Safety completed its study of safety in U.S. underground coal mines; the results of the study were published in the National Research Council report entitled Toward Safer Underground Coal Mines. One of the findings of this study was: THERE IS A STRONG CORRELATION BETWEEN MINE SIZE AND FATAL INJURIES. THE FATALITY RATE IN MINES WITH 50 OR FEWER EMPLOYEES IS NEARLY THREE TIMES THAT OF LARGE MINES (WITH OVER 250 EMPLOYEES), AND ABOUT TWICE THAT OF INTERMEDIATE-SIZED MINES (WITH 51-250 EMPLOYEES). Although the Committee explored possible reasons for the higher fatality rate in the smaller mines, it was not able to explain this phenomenon fully. Therefore the Bureau of mines requested that the Committee undertake a supplementary study of fatalities in small underground coal mines. The Committee met in the fall of 1982, discussed the problem, developed an approach to it, approved a program of statistical analyses, and authorized a panel of four committee members to explore the problem in greater depth. The panel, in turn, reviewed the results of the statistical analyses and met with the president of the National Independent Coal Operators Association and with several owners of small underground coal mines for a detailed discussion of the unique problems of small mines. Panel members examined 66 individual fatality reports prepared by Mine Safety and Health Administration (MSHA) inspectors who investigated fatal accidents that occurred in small underground coal mines in 1979 and 1980. This report is the result of those studies, analyses, and deliberations. The first draft was prepared by the panel, but the report has been reviewed and approved by the entire Committee.

Jan 1, 2011

By James W. Wade

This paper describing the mining practices at the Tintic Standard mine is one of a series being prepared by the United States Bureau of Mines. In the preparation of this paper each subject has been presented by the engineer in charge. L. R. Dobbs wrote the part pertaining to tae technique of square-set mining, J. M. Snow the part on geology, and M. D. Paine, the part on ventilation. All of the drawings are the work of H. W. Waterfield of the engineering department. The statistics of the Tintic district ware prepared by A. G. MacKenzie. Each writer has attempted to show the difficulties that arise in operating and the practices used to overcome them.

Jan 1, 1930

By W. R. Huff

This report describes the development and operation by the Bureau of Mines of a pilot plant designed for using high-volatile A bituminous coal-in-water suspensions as a source of preheated coal and superheated steam in the pressure gasification of coal with oxygen. Figure 1 on page 2 is a block diagram of the integrated gasification process, in which a total of 70 tons of coal was fed from slurry and gasified. The present work included (1) development of equipment and methods both for mixing pulverized coal and water to produce slurry and for pumping and metering the slurry at gasification pressure; (2) development of equipment for heating the flowing slurry and, because slurry that can be pumped produces more steam than is necessary as a gasification reactant, developing equipment for removing and metering the excess steam; and (3) demonstration of the process under actual gasifier operating conditions, at a coal rate of about 800 pounds per hour and gasification pressures in the range 100 to 300 pounds per square inch gage. By using the forced-convection principle, a flow of slurry made from a caking, high-volatile A bituminous coal can be continuously heated to 600° F. in a coil-type heater. The flow rate and concentration of the slurry and the temperature gradient along the length of the heating coil must be closely controlled. In a radiant-type heater, involuntary reductions in flow rate, even momentary, can lead to coking and plugging of the heater coil.

Jan 1, 1961

By S. P. Sandoval, A. E. Clark, S. W. Yopps, J. S. Gomer

The U.S. Bureau of Mines conducted Cu exchange tests for six common clays under simulated in situ leaching conditions. Regression equations were obtained from the data expressing the Cu exchange capacity as a function of Cu concentration, pH, and temperature. Using these equations, an analysis was made of the impact each clay could have on overall Cu recovery. The results suggest that Ca and Na montmorillonite clays could have a major impact on Cu recovery and that attapulgite and illite clays could have a smaller, but still significant, impact. Kaolinite and ripidolite clays pose little threat to loss of Cu from in situ leaching solutions.

Jan 1, 1992

By LaMar G. Evans

The rapid determination of uranium in ores by radiometric means was investigated by the Bureau of Mines. Among the various procedures and schemes tested, two showed most promise. They were the ratio scheme developed in the Bureau's Tucson, Ariz., laboratory and the equilibrium method developed by the Canadian Department of Mines and Technical Surveys. The ratio method is a simple, empirical procedure for classifying the state of equilibrium in ores by measuring their radioactivity by means of a Geiger-Muller counter under three different conditions, using filters. The principal merit of the method is in providing a clue as to the reliability of equivalent uranium determinations.

Jan 1, 1958

By Joseph A. Holmes

The perpetuation of the supply of anthracite coal in Pennsylvania is a national as well as a State problem. Any investigation that shows how larger percentages of this coal may be saved in mining, without excessive cost, and without dangerous subsidence of the overlying surface ground, has a national as well as a local interest. Messrs. Conner and Griffith, who conducted the investigations described in this report largely for the city of Scranton, are consulting engineers for the Bureau of Mines for investigations similar to those they have already made in connection with their Scranton work; and this report is published by the bureau in response to numerous requests, because of the fact that the information it contains will prove useful in the general solution of similar problems in many of the country's coal fields. A study of the accompanying maps will show that the city of Scranton is underlain by 11 separate beds of coal, varying in thick- ness from 2 to 24 feet. It is estimated that before mining opera- tions were begun these beds of coal contained underneath the present city limits of Scranton 600,000,000 tons of coal. The 27 collieries operating within the city limits, working independently of each other, had excavated and removed, up to March, 1911, an aggregate of 198,000,000 cubic yards of coal and accompanying rock, or 3,000,000 cubic yards more than the total amount of material excavated and to be excavated by the United States in constructing the Panama Canal. This fact illustrates something of the magnitude of the problem that the city of Scranton, with the aid of these engineers and of a special commission or advisory board, has undertaken to solve. The excavation has included 177,000,000 tons of coal and 44,000,000 tons of rock and accompanying refuse. This leaves about 420,000,000 tons of coal still to be removed. As a result of other investigations and of experience in adjacent anthracite mines, Messrs. Conner and Griffith and the advisory board of engineers have advised that, as far as may be necessary to prevent dangerous surface subsidence, the spaces remaining beneath the city of Scranton from the excavation of the above-described material should be filled with sand and other materials by flushing or other processes. This operation is expensive, but it is believed to be not beyond the reach of what is practicable, nor in excess of the value of the coal that may be removed and the amount of damages that may result from the caving in of the surface if such a plan is not carried out. No one realizes so fully as do the authors of this report the need of additional tests and other investigations before the data now pre- sented by them can be fully accepted as sufficient for all purposes in the solution of the problem; and it is expected that at some early date a more extensive series of similar tests can be made by the Bureau of Mines under the supervision of Messrs. Conner and Griffith on a larger scale and under a greater variety of conditions. The field examinations made for the Bureau of Mines by N. H. Darton, which are described briefly in a chapter of this bulletin and will be discussed at length in a bulletin to be published later, indicate the extent and distribution of the sands, gravels, and other materials in the Scranton-Wilkes-Barre district available for flushing purposes if further tests indicate their relative merits; and it is expected that the relative merits of these different materials will soon be tested under such conditions as will furnish the desired information.

Jan 1, 1912

By Oliver Bowles

"INTRODUCTION Slate has earned a high reputation as a roofing material, carefully selected and properly placed it is rainproof, attractive, and extraordinarily durable. Despite there qualities in its favor, the slate industry during the past 30 years has suffered marked reduction in volume of sales. An increase in building construction and general improvement in business will doubtless bring renewed activity, but considerable ground has to be recovered before the industry can become prosperous. Influences tending to dwarf this long-established industry producing materials of world-wide reputation are analyzed briefly in the following pages in the hope that they may be rectified.HISTORY OF SLATE PRODUCTIONFigure 1 shows graphically the rise and fall from year to year of sales of roofing slate since 1885. In quantity, the peak was reached in 1902, and the most serious decline was from 1912 to 1918, sales at the end of this 6-year period being only one third those at the beginning. Unlike most building materials, slate experienced only a slight recovery in volume of sales during the post-war period, 1920-29. The value closely parallels the volume up to the World War period. Subsequently, however, as unit values increased the aggregate value rose sharololy above the volume curve, attaining in 1928 the point reached in 1903, although the Lumber of squares sold was scarcely one third as great. The increased unit value was due partly to larger sales of heavy architectural grades."

Nov 1, 1933

By E. L. McHugh, R. T. Mayerle, J. M. Girard

Ground control problems at surface mining operations can occur for a variety of reasons. Stress, gravity loading, rock strength, geology, pore pressure, weather effects, underground workings, and many other factors contribute to slope instabilities that range from small rock falls to massive slides of material. While some of these failures can be predicted or controlled by preventive measures, each year many completely unexpected failures occur. Current methods for monitoring generally involve measuring displacements at a few, selected points in and around the suspected area of instability. While most of the displacements along these points will be in a downslope direction, freeze-thaw cycles of water-filled joints, horizontal stresses or pressure, buoyancy in saturated soils, human measurement errors, or other situations can produce deformation in almost any direction, even without any instability in the slope. Determination of which, if any of the observed movements represents a potential hazard is essential. Because of the enormous surface area of many large open-pit mines, several varieties and scales of instability can occur. Small, unexpected rock falls may indeed be more hazardous than a massive failure that involves slow displacement of material over a longer period of time. Complete vigilance to detect all small potential falling blocks is neither feasible nor economical and certainly is not attainable using today's most common point displacement monitoring techniques. As part of an on-going study at the Spokane Research Laboratory, several new methods for monitoring slope instabilities are being investigated. This paper describes the potential adaptation of systems such as interferometric synthetic aperture radar, imaging spectroscopy, and time-domain reflectometry, to slope monitoring and design.

By C. L. Brown

The frequency of mine fires during recent years, with an apparent increase in recent months, has focused attention on the necessity of reducing this hazard by every means possible. Investigation reports are available on 51 mine fires of electrical origin between August 15, 1949, and August 16, 1954. Nine other fires in the same period were suspected as being of electrical origin. Every mine fire is a potential hazard to underground workmen; it is remarkable that only six lives were lost as a result of these fires, since the injury list was very high. Modern mining methods, with increased power demands and extended distribution systems underground, involve greater electrical hazards and possibilities of costly production delays as a result of inadequate electrical service. Improvements in electric-power-distribution facilities in many underground coal mines is desirable. The purpose of this paper is to show the need for this improvement as revealed by studies and investigations of electric-power-distribution systems representative of those in a large number of coal mines.

Jan 1, 1955

By William E. Dennis

"At the request of Philip S. Hoyt, the Eagle Mountain fluorspar deposits in section 35, block 68, Texas & Pacific Railroad Survey No. 9, were examined by an engineer3/ of the Bureau of Mines during March 1943: As a result of this examination; a preliminary program of trenching, sampling and core drilling by the Bureau of Mines was begun in. June 1943.4/ Eight deposits were explored.The Federal Geological Survey mapped the properties and furnished geologic information throughout the program, while the Texas .Bureau of Economic Geology6/ made preliminary maps that facilitated planning the exploratory work on section 35.The eight deposits explored by the Bureau of Mines are in block 68, Texas & Pacific Railroad Survey No. 9, Hudspeth County, Tex., approximately 7-1/2 miles south of. Hot Wells and 12-1/2 miles south of Allamoore, which is 10 miles west of Van Horn and 20 miles east of Gierra Blanco on U. S. Highway 80(fig. 1). A graded gravel road, built by the Public Roads Administration, leads from Hot Wells to the deposits in section 35, and there are unimproved roads, passable,by automobile, to all the other deposits.Carload shipments can be made to and from Hot Wells on the Southern Pacific Railroad, and complete railroad facilities are available at Allamoore on the Texas & Pacific Railroad.Van Horn and Sierra Blanca are the only local source of labor and. supplies. The prevailing wage for common labor is 60 cents an hour. Living accommodations are obtainable in Horn and Sierra Blanca.No electric power lines pass near the deposits. Diesel and gasoline motors are employed to furnish power for mining and milling operations.Two recently 'drilled water wells on section 35 furnish water for the mill. Other wells will be drilled if the present supply is inadequate for prolonged Peak operation.The properties lie in the foothills on the northeast side of the Eagle Mountains at 5,500 feet altitude. The Eagle Mountain Range rises sharply from a broad, flat valley known as Eagle Flat. Eagle Peak, the highest in the range, has an altitude of 7,510 feet. In the vicinity of the fluorspar deposits the topography is moderately reliefs ranging from 50 to 300 feet."

Jun 1, 1946

By C. E. Rork

This paper discusses various mechanical improvements that have been gradually incorporated in the copper-willing plants of the Southwest daring the past 14 years, power plants for concentrators, use of large-size units of equipment, and the effect of plant capacities on costs. The improvements in mechanical equipment and plant design have contributed in the reduction of operating costs; in some instances a saving in the capital cost per ton of daily capacity milled has resulted.

Jan 1, 1935

By M. A. Trvits, M. Cummins, A. C. Smith, T. P. Mucho

This paper evaluates the effectiveness of remotely applied nitrogen-enhanced foam to aid in efforts to isolate and suppress a mine fire. The foam, in combination with a remotely-installed cementitious mine seal and a novel borehole pressure sampling methodology to determine the location of the suspected ignition source, was used to help control ventilation and inert the area surrounding the suspected ignition source by isolating it from oxygen. This allowed mine rescue teams to safely enter the mine, seal the area, and begin recovery operations to successfully return the mine to full production.

By A. T. Coumbe

The first national survey covering sales of fuel oil by States and principal uses was made in 1926 by E. B. Swanson of the Bureau of Mines (then under the U. S. Department of Commerce) under a cooperative agreement with the American Petroleum Institute. This annual study, covering the market for fuel oil, was made through 1930 with the financial help of the institute bat has since been continued by the Bureau up to the present time. The scope and coverage of the survey have gradually changed over the years as new uses for fuel oil have been found and new products have come into importance resulting in market expansion. Range oil (No. 1 fuel oil or kerosine) came into use for cooking and space-heating daring the depression era in New England, and it was first reported as a total in the 1931 survey. In 1934 the sales were compiled on a State basis. State totals for distillate fuel oil, Diesel fuel, and residual fuel-oil sales were first shown for 1934 and by principal uses and States in 1937. Kerosine deliveries by States and main uses were also released for the first time in 1937.

Jan 1, 1952

By H. B. Hill

The discovery of the Oklahoma City field and its .rapid development into one of the major oil-producing districts is an outstanding epoch in the history of the petroleum industry not only of .Oklahoma but also of the United States. The relatively great depth to which the wells were drilled and the large initial production of high-gravity oil are of special significance. The field has boon under proration almost from the time that its development began, and many new production problems have developed out of the changed conditions of operation. The discovery well was first tested in December 1928 at a depth of 6,402 feet, with an initial production of 4,847 barrels of 38.5° A.P.I. gravity and several months later was completed at a depth of 6,624 feet. The large initial production, the high pressure, and the large gas volume in the different horizons of the discovery well suggested the potential possibilities of gas and oil, production in formations of Pennsylvanian and pre-Pennsylvanian age.

Jan 1, 1933

By H. B. Hill

The discovery of the Oklahoma City field and its rapid development into one of the major oil-producing districts is an outstanding epoch in the history of the petroleum industry not only of Oklahoma but also of the United States. The relatively great depth to which the wells were drilled and the large initial production of high-gravity oil are of special significance. The field has boon under proration almost from the time that its development began, and many new production problems have developed out of the changed conditions of operation. The discovery well was first tested in December 1928 at a depth of 6,402 feet, with an initial production of 4,847 barrels of 38,5.° A.P.I. gravity oil, and several months later was, completed at a depth of 6,624 feet, The large initial production, the high pressure, and the large gas volume in the different horizons of the discovery well suggested the potential possibilities of gas and oil, production in formations of Pennsylvanian and pre-Pennsylvanian age.

Jan 1, 1933

By John H. Soulé

This paper describes the location and general features of the ?Red Bed? or sandstone copper deposits in southeastern Colorado and New Mexico. Most of the areas containing this type of deposit were visited, and many deposits were examined. Some deposits were not visited because of lack of information as to their location. In the large area covered a great variety of climatic, geographic, and topographic conditions exists. Some of the deposits are in arid areas, whereas others are in heavily forested regions. Altitudes range from 3,400 to 9,200 feet, and the terrain varies from flat plains to rugged mountains. Transportation is a difficult problem in most of the districts, involving long truck hauls to a railroad and long rail hauls to a smelter.

Jan 1, 1956

By Frank E. Cash

Published or available data on safety in quarries are few except those pertaining to blasting issued by manufacturers of explosives. During the past 25 years the quarrying industry (including various types of quarries producing many different materials) has had a markedly improved accident experience. The downward trend has not been phenomenal or has it been uniform from year to year, owing to occasional major disasters; but from the information at hand it appears that improvement during the 25-year period has been definite.

Jan 1, 1941

By F. P. Haver

Primary lead is produced in the United States by the pyrometallurgical smelting of lead sulfide (galena, PbS) concentrates, which poses sulfur dioxide and lead air pollution control problems. The Federal Bureau of Mines has investigated an alternative hydrometallurgy procedure that does not generate gaseous sulfur oxides and diminishes the potential for the escape of lead into the atmosphere. The procedure involves leaching galena flotation concentrates with ferric chloride (FeC13) solution to obtain lead chloride (PbC12) and elemental sulfur as expressed by the following chemical reaction: PbS + 2FeC13 ? PbC12 + 2FeCl2 + S°. At 100° C, over 99 pct of the PbS in the concentrate is converted to PbCl2 in less than 15 min. The leach solution, composed of brine (NaCl) containing slightly more than the theoretical required amount of FeC13, dissolves the PbC12 as it is formed, leaving a residue of elemental sulfur plus gangue. High-purity PbC12 (>99.9 pct) crystallizes from the leach filtrate on cooling and is electrolyzed in a low-temperature, fused-salt cell to obtain corroding-grade metal (>99.94 pct Pb). Spent leach solution (FeC12) is regenerated for further use by reaction with the chlorine obtained in the electrolysis of lead chloride. Other values, such as Ag, Cu, Zn, and S°, are recovered by additional treatment of either the leach solution or leach residue.

Jan 1, 1976