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By G. M. Kintz, E. H. Denny

Although some engineering colleges recognize the importance of instructing young engineers in industrial safety , the different institutions handle this instruction in various ways . It is believed that a recent industrial safety course , conducted at the Colorado School of Mines through the cooperation of this school and the Bureau of Mines , U. S. Department of Commerce , presents some unusual features that are of interest to other schools and to the mining public .

Sep 1, 1930

By Frank K. McIntosh

The Wood mine area was investigated by the Bureau of Mines in -1941 by a magnetic survey and a gravitational survey. Surface trenches were excavated, and diamond-drill holes were bored at the strongest anomalies developed in common by the two surveys. In the last century', several widely separated bodies of chromite with some magnetite had been exploited in a 'serpentine belt near its contact with schist. At one time this district held a virtual monopoly on the production of chromite. Known ore bodies now are exhausted. Owing to the relatively high specific gravity of chromate compared to normal rocks, a gravitational survey was run to determine which magnetic anomalies were worthy of diamond drilling. Linear feet of trenching totaled 1,710 feet. Ten holes were diamond drilled, which totaled 2,272 feet. The log of the drilling is shown in the text in a tabulation of drill-hole data.

Jan 1, 1948

By C. J. Johnson, C. J. Bise

"As the US coal industry moves into the next century, it is becoming more apparent that the effective application of new technology is the only way it can remain competitive in the energy marketplace. Examples of this emphasis are with us today in such diverse areas as face-ventilation and excavation-equipment applications. The focus of this new technology is directed toward improvements in health and safety, cost control, and productivity.Room-and-pillar mining accounts for approximately 68% of the nations underground coal production; this percentage is not expected to decrease markedly in the near future. As such, this paper analyzes the impacts of the changing technological climate on future room-mid-pillar operations by comparing a base-case section (current) to three scenarios incorporating new or emerging technology. A microcomputer-based comparative analysis will reflect the changes in section production and costs.IntroductionThe ultimate goal for any coal mining company is to effectively use its human and financial resources to maximize its profits through the extraction of its reserves. Although recent workforce reductions in the industry have resulted in a more efficient use of labor and increased productivity, there comes a point in time when further reductions in the numbers of workers in each operating section are impossible with existing equipment. For example, Farinelli and Bise (1987) found that labor cost constituted 62% - 73% of the cost per ton of coal at the mining section, with a minimum crew size. Thereafter, efforts to increase productivity must focus on more efficient mine plans and technology.The fact that an increase in productivity can be realized by reducing non-productive time (change-out and tram time) and converting it to productive time has been known and demonstrated for quite some time. What has not been demonstrated frequently is the quantification of the potential productivity increase of currently emerging technology or ""add-on"" equipment. It is one thing to be able to say that a piece of equipment will make an operation more productive, but it is another thing to be able to quantify the productivity increase that will justify the purchase of the new equipment. Not only is a financial benefit possible in room-and-pillar mining with an increase in productivity, but a decrease in the time necessary to develop a longwall panel can also occur.The purpose of this paper is an analyze the impacts of a changing technological climate on future room-and-pillar operations by comparing a base-case section (current) to several scenarios incorporating emerging technology. To do this, four cases will be developed. A base case, consisting of the typical manner in which continuous-miner sections are currently operating, is compared to three layouts incorporating: (1) flooded-bed scrubbers on radio remote-controlled continuous miners, (2)a continuous miner with side-mounted roofbolters, and (3) a continuous miner with side-mounted roofbolters used in conjunction with a continuous-haulage system."

Jan 1, 1989

By D. W. Frommer

The investigation reported in this paper is one of several included in a broad program of developing new or improved concentration processes for the oxidized and partly oxidized deposits of lead and zinc, A sample from the Playter lease, Newton County, Mo., containing pyromorphite was successfully concentrated by fatty acid flotation to a grade of over 62 percent lead. Owing to the presence of a high content of slime-size values, the overall recovery of lead at that grade was limited to 44 percent. DESCRIPTION AND HISTORY OF PROPERTY The mineral pyromorphite is a chlorophosphate of lead containing 76.4 percent lead, and, although it occurs frequently in association with other lead minerals, it is considered a minor ore mineral of lead. The manner of occurrence of oxidized lead minerals, including pyromorphite, which frequently are no larger in grain size than the clay with which they are found, militates both against development of a simple beneficiation process and high recovery. The profitable exploitation of such deposits depends not only on a successful treatment procedure but a highly favorable metal market as well. For these, and perhaps other reasons, very little research has been done on the recovery of pyromorphite from its deposits.

Jan 1, 1956

By Clyde L. Brown

Recent developments in portable communication equipment for use in emergency recovery work following mine fires and explosions have wade possible a convenient and dependable means of directing rescue teams working under hazardous conditions. INTRODUCTION Mine rescue and recovery operations following; fires and explosions are frequently conducted under adverse conditions that require the use of oxygen breathing apparatus by members of a 5- or 6-man team. Conventional apparatus used for this purpose for many years was equipped with an oxygen supply adequate for at least 2 hours. The design of the apparatus is such that the nose passages are closed with a clamp, and breathing is accomplished through a mouthpiece connected to the apparatus by tubes and arranged to prevent inhaling air or gases from outside sources. The use of the mouthpiece has presented difficulties in the development of telephone communication because of the wearer's inability to speak while wearing the mouthpiece. The method of conducting operations of rescue teams requires a person to direct operations at a fresh-air base as close to the rescue team as possible. At least one standby rescue team and 2 or 3 other persons assigned to various tasks are stationed at the fresh-air base. An efficient and reliable means of communication between the director of operations and the rescue team is necessary for reasonably safe and efficient work in hazardous areas.

Jan 1, 1957

By J. C. Franklin

The Bureau of Mines substantially reduced shale degradation in a coal mine by two spray coat applications of a water-base epoxy sealant. More than 12,700 square feet of passageways were treated, and in 18 months only one failure occurred. This failure was due to improper spray application, Material costs averaged 13 cents per square foot, and labor costs were 7 cents per square foot. Labor included moving all materials into the mine, the setup time for each of the areas coated, and application of coatings.

Jan 1, 1977

By L. J. E. Hofer

The Bureau of Mines determined rates of adsorption and desorption of methane as a function of particle size and temperature, using coals from the Pocahontas No.3 seam (lvb) from the Bishop mine of western Virginia, and the Pittsburgh seam (hvab) from the Pursglove No. 15 mine of northern West Virginia. For a given coal sample and temperature, the rate curves for adsorption and desorption are essentially the same when expressed on a fractional approach to equilibrium basis. The rates of adsorption and desorption increased eightfold as the particle size was decreased from 6-8 to 270-325 mesh per inch. The adsorption process appears to be diffusion controlled. Rate of sorption processes increased with increasing temperature; however, the amount adsorbed at equilibrium decreased.

Jan 1, 1966

By H. E. Perlee

The concentration limits of flammability and autoignition temperatures of trichloroethylene in atmospheres of air, oxygen, and nitrogen tetroxide have been determined in a spherical vessel. The autoignition temperatures of TCE in atmospheres of air, oxygen, and nitrogen tetroxide were found to be 419°, 396°, and 221° C, respectively. The flammability zones of TCE-air, TCE-oxygen and TCE-nitrogen tetroxide mixtures at 100° C were found to be 10.5 to 41, 7.5 to 91, and 13.5 to 69 volume percent TCE, respectively. In addition, maxi-mum combustion pressures of 50 ps and 140 were recorded for constant volume combustion of the lower limit mixtures of trichloroethylene in air and oxygen, respectively.

Jan 1, 1966

By H. D. Baylor

This paper, describing the operations of the Louisville Cement Co. in quarrying limestone for the manufacture of quicklime, is one of a series being prepared for and published by the United States Bureau of Mines on stone quarries throughout the United States. Those papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating only and not total costs. It is recognized that publication of total costs might in many instances cause embarrassment to individual operators as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author acknowledges the assistance of J. H. Lemmon, plant superintendent, Charles Taylor, plant engineer, and F. H. Compton, chief engineer, of the Louisville Cement Co. in the compilation and preparation of this paper.

Jan 1, 1932

By C. A. Komar

Renewed interest in the underground gasification of coal evolves from comprehensive studies of earth fracture systems that indicate that the movement of fluids can be controlled in the coalbed. In particular, directional property studies of natural microfissure occurrence, permeability, ultrasonic velocity, tensile strength, and orientation of intervals of inherent rock weakness, together with geologic structure setting and fracture trace analysis, can predict the gaseous flow paths in the coalbed. Having this information, the dominant direction in which gases generated and/or liberated by heat would move can be determined so that appropriate well patterns can be developed. Together with advances made in drilling technology that permit long horizontal holes to be drilled through the coal seams, tests can be conducted to determine whether directional control will permit devolatilization of the coalbed and gasification of the remaining hot coke in a systematic manner to produce a low-Btu gas suited for the generation of electricity.

Jan 1, 1973

By Merle Randall

Application of a new chemical spray in a mercury mine in which ore rich in native metal was causing salivation among the miners has given such favorable results that it is believed the process will be useful in other mines and perhaps in some plants where similar conditions exist. The process was originated by Merle Randall, professor of chemistry at the University of California. GENERAL PROBLEM The presence of native quicksilver in mines from which the metal is produced has long been a source of trouble and danger to the workers. Men have been sickened and some of them have been disabled by exposure to the vapors present (even in workings that were well-ventilated by ordinary standards) and to contact with dust, dirt, and moisture with which the finely divided quicksilver was mixed. Where the ore was rich and this exposure was considerable men were able to work only a few days or weeks; where the exposure was less they were weakened and subject to ailments often attributed to other causes.

Jan 1, 1942

By R. M. Gammell

"INTRODUCTION The Farmer prospect was examined by W. R. Green, an engineer of the Bureau of Mines, in June 1944. As a result, studies of this property were included in a general preliminary investigation of the Etevens County lead-zinc deposits by the Bureau in 1945. The exploratory work was designed chiefly to supplement the surface examination by determining the nature of the mineralization below the zone of oxidization. The results of the small-scale diamond-drilling program undertaken at the property are presented in the following report.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization our resources to the end that they make the greatest possible contribution to security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work and prepares the filial report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

Mar 1, 1947

By D. J. MacDonald

The Bureau of Mines investigated two alternative methods for treating a zirconium-bearing chloride-sulfate strip liquor to obtain reactor-grade Zr02. One method involves neutralization with NH3 and the other hydrothermal precipitation. The strip liquor was derived from zircon sand by a Bureau of Mines method for separating zirconium and hafnium via solvent extraction with a tertiary amine. Neutralization with NH3 to precipitate hydrous zirconium oxide required 0.9 to 1.1 g NH3 per gram of zirconium. The NH3 can be recovered for recycle. Zr02 that met reactor-grade specifications was produced by precipitation with NH3? Hydrothermal precipitation of Zr02 from strip liquor required that the solution be maintained at 2600 C and 680 psi for 10 min and in a non-corrodible pressure vessel. In bench-scale experiments both methods gave-zirconium recoveries greater than 99 pct.

Jan 1, 1984

By E. W. Pehrson

In making any canvass of secondary metals great care must be exercised to avoid duplication or exaggeration of net consumption. One of the major difficulties is to trace the metal accurately as it passes through the many cycles of manufacture. Greater or less duplication probably occurs in any canvass. The manufacturer of tin plate, for instance, purchases primary pig tin exclusively as a raw material. Most of it goes into the coating on the steel sheet, but a substantial part emerges in the form of byproducts such as scruffs and drosses. These are sold to other plants, where they are used in the manufacture of alloys and chemicals. Alloys and chemicals, however, are not necessarily articles for final consumption. The alloy may be sold in ingot form to a bearing manufacturer, who, in turn may produce some scrap, which he may sell to still' another plant that may make still other products. There is a considerable return of tin in the form of waste products from chemicals sold to the silk industry. Even tin plate does not represent an ultimate use of tin because the tin-can maker produces large amounts of clippings, which are sold to detinning plants, where the tin is recovered and used again for some other purpose. Thus the degree of duplication in consumption statistics depends on the point in the industrial cycle where consumption is measured.

Jan 1, 1936

By Oliver Bowles

"Introduction.During recent months the Bureau of Mines has conducted a detailed study of the slate industry with special reference to increased efficiency in its production, preparation and utilization. The results of these investigations will be incorporated in a forthcoming bulletin. The purpose of this preliminary paper is three-fold. One object is to bring to the attention of slate producers certain modifications in manufacture and classification which would encourage a wider use of slate. A second purpose is to direct the thought of roofers toward the importance of proper laying of slate, and the third object is to acquaint the general public with its enduring qualities.Origin and character.Without entering into any detailed discussion of the origin and history of slate, a subject to be covered in the bulletin mentioned, it may be of interest to the general reader to know that slate is originally formed from mud or soft clay, carried down by streams and laid down in successive layers in deep water. The pressure of superimposed materials gradually compresses the clay into a firm rock known as shale. In many places this shale was, during the succeeding ages, subjected to intense pressure and folding due to mountain-building forces within the earth. This intense pressure, together with high temperature, changed the clay into other minerals such as mica, chlorite, and silica, which are very resistant to weathering, and also developed a very definite cleavage or splitting direction which characterizes the rock as slate. It is this property which renders slate of value for roofing, for, by using a broad chisel and a wooden mallet, a slate worker can readily split it into thin sheets which are later trimmed into rectangles of various sizes."

Jul 1, 1921

By John P. McDonnell

This U.S. Bureau of Mines report describes the results from an in-mine investigation of an alternative longwall gate road design. The coal mine operator modified the pillar layout (reversed the location of the big and small pillars) in a portion of a three-entry longwall gate road area. The modified pillar layout was an attempt to reduce stress and, subsequently, stress-related ground control problems (cutter roof and dynamic floor heave events) in the tailgate region during "second-panel" mining. The results from borehole pressure cells installed in the modified gate road area showed that the ground pressures in the panel edge and adjacent small pillar were significantly reduced during second-panel mining compared with ground pressures experienced in the typical pillar layout gate road areas. The reduced stress levels around the tailgate entry adjacent to the second panel, as compared with the tailgate stress levels with the typical pillar arrangement, contributed to improved tailgate ground conditions in the test pillar zone.

Jan 1, 2010

By Marting J. Gavin

The twentieth century has often been spoken of as the age of petroleum, and from many viewpoints it can be justly considered so. Certainly the petroleum industry is one of enormous importance to this country, industrially, financially, and economically. The United States, however, at present producing over 60 per cent of the world's total output of petroleum, is not producing petroleum at a sufficient rate to provide for its own domestic, consumption. For several years this country has been importing increasing quantities of crude and partly refined oils from Mexico, and has been drawing heavily on domestic stocks of petroleum. Production in the United States is increasing, but it is not increasing at the same average rate as domestic consumption, nor is it probable that in the future domestic production will increase sufficiently to satisfy the demands of domestic consumption, but on the contrary, in the opinion of those best qualified to know, the peak in the curve of domestic production of crude petroleum will be reached in a comparatively few years, whereas the consumption of petroleum and its product will increase at a continually growing rate. This country, then, must turn, and as the increasing imports from Mexico indicate, is turning to other sources than the crude petroleum, produced in this country to make up the deficit between domestic production and domestic consumption of petroleum and its products,

Jun 1, 1920

By A. J. Rambosek

An evaluation of diamond-bit performance data accumulated from core drilling in quartzite shows that core recovery and physical characteristics of drill bits and diamonds have economic significance. Relatively inexpensive, low-quality, small Congo diamonds will perform as well as, or better than, other diamonds used as drill bart. M-type bits set with oriented Congo diamonds provide those engaged in core drilling with near optimum combination. Various factors that affect bit performance, including size of diamonds, size and type of bits, grade or quality of diamonds, and percentage of core recovered, are evaluated by means of tables, charts, and discussion.

Jan 1, 1958

By Edward F. Divers

Tills U.S. Bureau of Mines report briefly evaluates the advantages and disadvantages of basic dust control techniques presently used by U.S. coal preparation and mineral processing plants. These include ventilation, baghouse-type collectors, wet scrubbers, electrostatic precipitators, source control, sprays, good housekeeping, and personal protection devices. Two specific problems in these types of operations are also considered: dust collector system duct clogging, and control room dust control. Information provided in this report results from dust control research projects conducted by the Bureau at various coal preparation and mineral processing plants over the past decade to reduce workers' dust exposure. These studies indicate that plant ventilation systems normally provide the most cost effective method for dust control. Baghouses and scrubbers were also effective in specific applications, and examples of each are given. In extreme dust conditions, personal protection devices, such as respirators or the dust helmet, can also be highly cost effective.

Jan 1, 1990

By W. P. Yant, G. W. Jones

During the testing of porcelain insulators with a " 60 - cycle flash - over apparatus " , gases are liberated having an odor greatly resembling that of ozone . Since the two main constituents of normal air are nitrogen and oxygen , and high voltages (approximately 90,000 volts ) are used during the tests , the conditions are favorable for the production of ozone or oxides of nitrogen , and perhaps both simultaneously . The presence of these gases is only noticeable during the testing period . They soon disappear after the test is over . No fatalities have ever resulted from these gases at the plant visited nor are there any records of any of the men who worked on the tests being confined to their homes from this cause . New employees sometimes complain of a depressed feeling and shortness of breath , which is most noticeable after leaving work and getting into fresh air , but they som become accustomed to it and no ill effects are noticed . In view of previous work*** which the Bureau of Mines has done on oxides of nitrogen in connection with mine gases and problems in gas analysis , tests were made at the plant of the Westinghouse High Voltage Insulator Company at Derry , Pa . to determine the kind and amount of gases liberated .

Jun 1, 1923