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Reduce fire warning time and avoid activation of false alarms in underground mines. Approach A heat activated stench/tracer gas system was developed which automatically releases the gas mixture into the mine ventilation air. How It Works A canister approximately 12 inches long and 3 inches in diameter is charged with 50 grams of ethyl mercaptan or other appropriate stench gas and 500 grams of instrument detectable Freon. The canister is then pressurized to 100 psi with nitrogen. A disc is used to seal the contents of the canister. A low-temperature alloy designed to melt at a predetermined temperature is used to restrain a spring loaded plunger. Upon exposure to heat, the alloy melts and the plunger is released. The plunger ruptures the disc and the mixture of stench and tracer gas is released from the canister. Canisters are mounted in areas of a mine which are susceptible to fire such as near

Jan 1, 1983

By Richard L. Unger

Equipment is the primary cause of injury in 11% of all mining accidents and a secondary cause in another 10%. Purchasers should select new equipment carefully to ensure that the machine incorporates good ergonomic design criteria that maximize the safety of their mine workers. One potential problem area is the workstation-the control center of the machine. Safety problems often occur when the workstation provides insufficient clearance or visibility to the operator or has controls that are difficult to reach. This is especially true for underground mines, where confined space is an issue. In reclined or stooped postures, operators will have less strength and agility and often experience reduced visibility. We have conducted and published much research in Human Factors design of mining machine workstations. This information is currently being compiled into a series of Human Factors design recommendation reports. The reposts dl cover many topics, including workstation layout, control design, seating, and visibility. Each topic has a list of basic or first principles of design. Understanding these principles is the key to designing or purchasing a workstation that is both safe and efficient. Following is a sampling of these main topics and first principles.

Aug 1, 1996

By T. E. Gray

This report describes the preparation characteristics of the more significant coal beds in Washington County, Pa. It is one of a series planned to determine coals suitable for producing metallurgical coke, either as mined or after beneficiation. More than 15 million tons of coal was produced in Washington County in 1956; 89.8 percent was cleaned mechanically in 10 cleaning plants. The Bureau of Mines has estimated that 2,280 million tons of recoverable coal remained in beds 28 inches thick or more as of January 1, 1954.

Jan 1, 1959

By Hillary W. St. Clair

The effective coefficient for rate of reduction of a sample of granular iron ore may be determined by passing the reducing gas through a bed of the are at constant flow rate and periodically analyzing the effluent gas, The method of analyzing the data is based on a mathematical model that takes into account the variation in composition of the gas and solids with time and position in the bed. A method is described for determining the value of the rate coefficient that gives best agreement between the observed and calculated analyses of the effluent gas.

Jan 1, 1967

By Stephen D. Smith

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Also included are tables that show the principal nonfuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of Volume I and in the State chapters of Volume II of this edition of the Minerals Yearbook. Although crude mineral production may he measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1989

By Rose L. Ballard

This chapter summarizes data on crude non fuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are the tables that show the principal non fuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production, The detailed data from which these tables were derived are contained in the individual commodity chapters of Volume I and in the State chapters of Volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1986

By Gregory J. Chekan

In This Chapter [Drilling, blasting, and crushers Diesel particulate Enclosed cabs Ventilation with jet fans Stopping construction methods Propeller fans as main fans] This chapter explains how to control dust in large-entry stone mines, including both silica dust and diesel particulate. Most stone mines are limestone mines, but a substantial minority are marble, sandstone, and granite mines. These mines differ from most others in that entry widths are 30 ft or more and entry heights are 25 ft or more. Such mines, developed with room-and-pillar methods, have large open areas that can make ventilation and dust control more difficult. Because of the difficulty of ventilating stone mines, improved ventilation is a major focal point of this chapter. However, the chapter also covers the control of dust from drills, blasting, and crushers. Another part of the chapter covers enclosed cabs, an effective dust control technique for some workers. BACKGROUND The major dust compliance problem in stone mines is caused by silica (quartz) in the rock. Mines in high-silica rock, 8% or more, are far more likely to have a dust problem than those where there is less silica. Geographically, the limestone in the Northeastern and South Central United States has higher silica than the rest of the country. Chekan and Colinet [2002] have analyzed Mine Safety and Health Administration (MSHA) dust sampling results [MSHA 2001] from the stone industry. They have concluded that, on average across the United States, the workers exposed to the highest dust concentrations are rotary drill operators, front-end loader operators, truck drivers, and crusher operators. However, there are many regional differences. Also, occupations that work outside of cabs, such as blasters, roof bolters, and laborers, can be exposed to high dust levels.

Jan 6, 2003

By BUREAU OF MINES

Atentative Draft of a standard smoke abatement ordinance has been prepared by a joint committee made up of representatives of the American Society of Heating and Ventilating Engineers, the Stoler Mamufacturers Association, the American Civic association, and the Fuels Division of the American Society of Mechanical Engineers. The Committee is desirous of obtaining helpful criticism and suggestions about this ordinance, which should be mailed to the chairman, Dr. O. P. Hooi, Bureau of lines, ashington, D. C. Te personnel of the committee is as follows: Dr. O. P. Hood, chairman, and Henry Kreisinger, representing the Fuels Division of the American Society of Mechanical Engineers; P. J. Dougherty, representing the American Society of Heating and Ventilating Engineers; Lloyd R. Stowe, representing the Stoker Mam- facturers Association; Everett L. Hillard, representing the American Civic Ascociation; and Osborn Monnett and Harry 3. Meller, members at large.

Mar 1, 1930

By E. D. Gardner

"The Bureau of Mines has studied blasting practices in metal mines of the Southwest. The investigation of blasting drift rounds showed among other results, that cut-holes in ground difficult to break could be chambered to advantage under some conditions.In open--cut mines, chambering nearly all holes before blasting is the common practice. Two or more free faces are generally maintained in this type of work, and the amount of explosive necessary to break any bench or bank can usually be estimated from the yardage to be moved. However, in blasting drift or tunnel rounds only one free face is available before the cut-holes are shot, and the quantity of explosive required is generally ascertained best by trial.In addition to being the most difficult to break, the cut-holes are the most important of a drift round. When the cut-holes ""break bottom"" less work is required of the other holes, and a full break of the round is generally obtained. In ground difficult to blast, extra care and expense are justified to insure that the cut-holes ""break bottom.""At many mines the work is so organized that all blasting is done at the end of the shift, and a decided advantage would have to be gained to make chambering of the cut-holes economical. Also, in many mines blasting during the shift would not be practical. One or two holes could probably be drilled during the time necessary to do the chambering. However, under certain special conditions, such as in small operations or those where ""leasers"" or contractors are working, drill holes could be chambered should there be an advantage in doing so. Moreover, in some mines it might be practical to chamber the cut-holes at the lunch hour. In ordinary rounds the cut-holes are generally drilled by noon. It would not be necessary to tear down the drill or remove tools from the face to do this work of chambering."

Feb 1, 1928

By A. L. Murray

"Welfare endeavor in connection with both the metal and the coal mines of Utah has shown gratifying progress during recent years, and in most mining towns of the state, both the operators and their employees deserve much credit for the efforts put forth to better the living, working, educational and recreational conditions. Progress has been and is being made, but there are still a few important towns where purer water and better sewage disposal are pressing needs.In the older metal-mining towns that are incorporated and are independent of the mining properties operating in the vicinity, less opportunity is presented for the companies to exercise efforts looking toward improved welfare conditions than in company towns controlled by the mine operators.However, even in such towns the companies can do much to better welfare conditions, as shown by the progress in Bingham Canyon during the past several years. The Utah Copper Company has spent $800,000 since 1920, in the erection of modern brick cottages, apartment houses and the Germnell Memorial Club. The cottages and apartment houses have every convenience to be found in up-to-date city homes. The Gemmell Memorial Club erected and equipped at a cost of $175,000 was provided by the company for the benefit of the Utah Copper employees living in the canyon and has been made the recreational center for the camp. Another improvement is the $100,000 fireproof hotel built by the United States Mine of the United States Mining, Smelting and Refining; Co. in the Copperfield section of Bingham Canyon. This hotel will accommodate 105 men exclusive of hotel help and has all the conveniences of a city hotel."

Sep 1, 1925

By James J. Olson

The Bureau of Mines recorded peak particle-velocity levels and vibration frequencies to determine the nature and intensity of ground vibrations for tunnel blast rounds at the NORAD Complex, Colorado Springs, Colo. Previous Bureau of Mines studies in quarries and underground mines had shown that scaling (dividing) the distance from the blast by the square root of the charge weight removed the effect of the various charge weights on vibration amplitudes. The analysis of variance tests performed on the NORAD vibration data, however, indicated that the cube rather than square root scaling exponent grouped the data more effectively. The empirical propagation equation, V = 560 (D/w1/3)-2.04, where V is the maximum peak particle velocity in inches per second, D is the distance from the blast in feet, and W is the zero-delay charge weight in pounds described the attenuation, with distance, of the particle velocities from the tunnel blasts in the Pikes Peak Granite of the NORAD Complex.

Jan 1, 1972

To enhance safety and efficiency when moving large mining equipment under energized trolley lines, and to assist in compliance with Section 75.1003.2, 30 CFR. Approach A system was designed, using established technology, that permits a remotely located circuit breaker to be controlled from the cab of a mine locomotive moving large mining equipment under energized trolley lines. This control consists of setting the desired trip current, automatic or manual tripping, resetting, and voice communications between the locomotive and a remote Circuit breaker location. How It Works According to 75.1003.2, 30 CFR, whenever a piece of off-track equipment (such as a longwall chock or a continuous miner) is moved by rail under energized trolley or feeder lines, power for the locomotive that is moving the equipment must come from only one' circuit breaker. This circuit breaker must be adjusted to permit no more than one-half its rated short-circuit current to flow. The intent is to lessen the danger if an accident should occur, and if the equipment contacts the trolley line. Even so, the danger is great. This half setting can still represent many hundreds or even thousands of amperes, enough to endanger personnel, the equipment, or the mine. The Remote Control System reduces this danger substantially by giving the personnel associated with the move total control over the associated circuit breaker. The system as designed, is intended to be used with portable circuit breakers that are pulled on a small flat car by a mine jeep, and either precede or follow the equipment, depending on the direction of the power. This portable circuit breaker is equipped with a commercially available solid state overcurrent relay and associated shunt. This circuit breaker is connected via heavy duty clamps around an open trolley line tie breaker such that the current through the shunt is also the current in the trolley line. A receiver, interfaced with the overcurrent relay and shunt, completes the remote system.

Jan 1, 1981

By H. E. Sanford

"INTRODUCTION Of the occupations in and about coal mines, those of the haulage crews are among the most hazardous. Statistics indicate that the second largest number of fatalities about coal mines occurs during haulage operations and through the use or misuse of haulage equipment. Despite the fact that relatively few coal-mine employees are engaged continuously at haulage operations, approximately 20 percent of all coal-mine fatalities are attributable to haulage.Most of the hazards in haulage operations could be very greatly reduced if more serious consideration were given to the problems of the haulage crews and if sincere efforts were made to reduce the hazards. Underground haulage is similar in many respects to railroading; yet, railroading is now considered one of the safest of occupations a distinction that has been attained only by honest effort and whole-hearted cooperation on the part of all concerned. Underground haulage is also similar to street and highway operation and has in it some of the difficulties encountered in the reduction of traffic accidents the seriousness of which has not by any means been con¬trolled as yet, notwithstanding the fact that much effort has been expended through a multiplicity of laws, ordinance regulation, etc., as well as by thousands of enforcement agencies and officers.The men working on the locomotives are among the most important members of a coal-mine organization; without skilled haulage employees, the production of coal would be greatly retarded. Their jobs, particularly the job as brakeman, require physical endurance, agility, and mental and physical alertness; in thin coal beds, especially where the roof is not brushed and the coal is loaded into mine cars by hand, the need for these qualifications is greatly increased."

May 1, 1948

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Jan 1, 2012

Develop a full-length-anchored roof bolt that is economical, nontoxic, nonflammable, and non-allergenic. Approach Grout roof bolts with a storable mixture of ultra-fast setting inorganic cement and water. How It Works A loose mixture of dry cement powder, and pinhead-size water droplets encased in waxy globules, are pack-aged in sausage shaped cartridges for storage and use. After the cartridge is inserted Into a drilled hole, the roof bolt is thrust In and rotated to mix the cement and water. The cement hardens in seconds, providing usuable anchoring strengths in minutes. Prior to filling of the sausage shaped cartridges, the microcapsules of water are Intimately mixed with the dry cement. The currently used grouting consists of a mixture of one part water (minimum) with three parts alpha-type gypsum cement and a minor amount of accelerator.

Jan 1, 1978

By John Durkin

Information on vertical magnetic noise in the voice frequency band, both within and above coal mines, is needed for the evaluation of through-the-earth baseband electromagnetic communications at mines where horizontal loop antennas are used. This report discusses the theory of the source of electromagnetic noise, the propagation of this noise to an observation point above a mine, and its interaction with the local earth conductivity structure, which gives rise to vertical magnetic noise. The relationship of surface noise to underground noise is also discussed. Bureau of Mines investigators made surface and underground vertical magnetic noise measurements at a number of coal mines located through- out the United States. These data were modeled through regression analysis to characterize expected noise levels. The results are presented, including results in one-third octaves for use in evaluating the expected performance of through-the-earth communication systems by articulation-index studies.

By Frank J. Susko

The U.S. Bureau of Mines has developed a computer model to describe a flotation process. Coal data from conventional flotation has been converted to a simple, two-parameter kinetic model developed by Reuter and van Deventer (1,2)3. Each set of coal data was represented by two constants, a and ß, and an average flotation rate. The success of the model was demonstrated when the calculated and experimental recoveries showed good correlation. The two-parameter model allows complex data to be defined much more efficiently than traditional knowledge-based models.

Jan 1, 2010

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

8. Refuge Chambers 8.1 Refuge Chambers - Technical Discussion 8.1.1 Introduction As a part of the overall escape system, refuge chambers can provide a last resort when existing escapeways are blocked. These chambers are intended to provide both protection from toxic gases and a life supporting environment for a period of time before external rescue or further escape efforts can be carried out Escapeways may be blocked physically (due to cave-ins, etc), by fire, or by the presence of a toxic or oxygen deficient atmosphere. In the first two cases, the trapped miners would most likely await external rescue efforts, and hence the design of the chamber will have to consider the time durations that such efforts may take, It is also possible, in the second case, for fire fighting and fire protective equipment to be stored in the chamber so that miners may attempt their own escape. In the third case, it should be recognized that a compact, beltmounted 1-hour self-contained breathing apparatus has been developed(9), and that other, less compact equipment is available for up to 4 hours of self-contained breathing supply. If such equipment were stored in the chambers, then miners could escape by travelling from chamber to chamber, taking temporary refuge in each before proceeding to the next. 8.1.2 Background The concept of "barricading" has long been recommended for those emergencies where miners are trapped inby a fire. Barricading, which is the construction of a makeshift shelter in a crosscut or deadend, protects the entrapped miners from toxic gases and enables them to conserve a supply of air. In this manner, they can survive two or three days--hopefully enough time for them to be reached by rescue teams. In the past, many lives have been saved with this technique.

Jan 1, 1976

By Frank A. Peters

This description of process evaluation techniques used by the Bureau of Mines for studying proposed processing techniques has been prepared to provide those interested in using these studies with an understanding of the methodology. The methods used for preparing both capital and operating cost estimates are described. Each step in preparing the evaluations is described. Types of equipment costs are shown and factors used in the estimates are defined. Uses of the estimates are suggested and several examples are included. The accuracy of various types of estimates is discussed, along with an explanation of the reason for selecting the type used in the Bureau's process evaluation studies.

Jan 1, 1987

By R. C. Wang

Solid-liquid flow in different pipe geometries was investigated. This investigation was conducted by measuring delivered solids concentration and head loss. The delivered solids concentration was measured to study the effect of pipe geometry on the minimum carrying velocity above which solids do not lag behind the fluid. Head loss was measured to study the effect of pipe geometry on the friction loss. A mathematical formula was developed for determination of the minimum carrying velocity. Darcy-Weisbach's equation and Durand's equation were used for comparison of head losses of pipe shapes. Of the different pipe shapes studied, each having the same interior cross-sectional area, the rectangular pipe with the wide side oriented as the base yielded the lowest minimum carrying velocity at high solids concentrations. The minimum head loss at low velocity and high solids concentration also was attained with this pipe. Although the circular section is known to be the best for transporting liquid only, the present study suggested that pipe geometry is a factor in lowering the operating velocity and reducing head loss in solid-liquid flow.

Jan 1, 1973