Search Documents

By Rudolf E. Greuer

The existing computer programs for the simulation of ventilation systems under normal ventilation conditions are reviewed and a suitable program for including the influence of mine fires is selected. New program parts are written for the consideration of methane productions in coal mines, heat and gas productions of mine fires, temperature and air composition changes in ventilation systems, and the ventilation forces resulting from the latter. Other program parts are provided for the detection of danger zones and reversed air currents and for the inclusion of recirculated air currents in the network analysis. Existing program and new program parts are combined. The resulting new program can be used for a multitude of assignments. It is designed for the practical ventilation engineer and should be applicable to all types of ventilation emergency plans, in particular mine fire plans. The organization of the program and its mathematical basis are described. A FORTRAN IV listing and several flow diagrams are included. Eight executed examples are discussed, input and output for these examples explained. Storage requirements and execution times are estimated.

Jan 1, 2011

By John F. Elliott

Six major trends that have had and are continuing to have major effects on the use and supplies of pig iron and scrap in the United States are (a) gradual replacement of the basic open hearth furnace (OH) by the basic oxygen furnace(BOF); (b) use of the electric furnaces for the production of plain-carbon steels, a trend which is closely related to the first; (c) United States changing from being a net exporter to a net importer of steel; (d) replacement of ingot casting by strand casting; (e) increased exportation of scrap; and (f) the lack of growth of the capacity of the U. S. steel industry to produce pig iron in the last 5 to 8 years. This report gives an analysis of the relationships between these trends and the use of processes for the production of raw steel in solidified form.

Jan 1, 1975

By Peter de Bakker

The objective of this contract was to develop a simple, reliable, economical, remote-control roof bolting module for installation of mechanical and resin bolts. It was to be capable of placing longer than seam height bolts, up to 10 ft lengths, from a seam height of 36 to 72 in., while keeping the operator under supported roof. The resulting machine, called REM-Bolter, is a low profile unit that utilizes Foster-Miller Flexible Shaft Roof Drill, a Bendix Roof Bolt Inserter and a newly designed. Roof Bolt Lifter/Torquer. Every effort was made to strike a compromise between complete automation and complete manual control. In a controlled laboratory environment the REM-Bolter remotely installed 1000 bolts. Subsequently the machine was tested in an operating coal mine where 500 holes were drilled (and an equal number of bolts were installed) remotely, over a 4 month period. The results of all tests Live shown that the operator of a machine of this kind can quickly, and repeatedly, install rootbolts remotely from his operator compartment some 8 ft away from the drilling/bolting action. The report includes recommendations for improvements to the present REM-Bolter design that would translate the present test bed into a second generation test bed and a potential first generation production unit.

Jan 1, 1983

By Forrest T. Moyer

All general measures of the safety record of the coal mining industry worsened appreciably in 1970. Injury experience for the year was 260 fatal and 11,552 nonfatal injuries at respective frequency rates of 1.00 and 44.40 per million man-hours of worktime. The fatality total was 57 higher and the rate of occurrence was 18 percent higher than the corresponding figures of 203 fatal injuries with a frequency rate of 0.85 in 1969. The worsened fatality record in 1970 resulted primarily from a major disaster (a single accident which results in the death of five men or more) on December 30, 1970, that killed 38 men. There were no major disasters in 1969. The total of 11,552 nonfatal injuries in 1970 was the highest annual total since 1960. It was 1,635 higher and the frequency rate was 6 percent higher than the corresponding totals for 1969 of 9,917 nonfatal injuries occurring at a rate of 41.76. The injury severity rate of 8,308 days lost or charged per million man-hours was 13 percent worse than that of 7,359 in 1969. Similarly, the average severity of 183 days lost or charged per injury in 1970 was 10 days or 6 percent higher than in 1969. Aggregate worktime of 260.2 million man-hours and production of 609.8 million tons in 1970 were, respectively, 10 and 7 percent higher than in 1969. An average of 144,480 men were at work on an average of 227 active days in 6,316 mines and 544 mechanical cleaning plants during 1970.

Jan 1, 1973

By Clyde L. Brown

The ignition source of fires and explosions in coal mines is sometimes difficult to explain because resulting widespread destruction often erases valuable evidence that might reveal the cause. However, through years of experience, investigators have been able to piece together enough evidence to establish the reasons and, thereby, have been equipped to recommend corrective or preventative measures. The pattern of hazards is not constant. It changes with the development of new practices and new equipment. Important among the new hazards to coal mining are those introduced by electricity. In addition to the dangers of electric shock, fires and explosions from heat and arcs, and premature blasts, certain others have developed as a result of stray electric currents from direct-current traction systems. The conventional direct-current power-distribution system in coal mines is conducive to electrolysis damage to mine tracks, metallic pipelines, grounded power conductors, and structures in a position to become conductors of stray currents. The voltage drop resulting from power demand on intentionally grounded power conductors and accidental grounds on insulated conductors are common sources of stray currents in coal mines. Uncontrolled electric cur-rents flowing through the earth and metallic structures can be a menace, and these contribute to the estimated $6,000,000,000 annual loss caused by corrosion. The purpose of this publication is to discuss some of the electrolysis hazards in the coal-mining industry and to outline corrective measures to alleviate them.

Jan 1, 1962

By E. D. Gardner

This paper is the third of a series of three on placer mining in the western United States. The first paper4 discusses the history of placer mining in the Western States and the production of placer gold, geology of placer deposits, location of placer claims on public lands, sampling and estimation of gold placers, and classification of placer-mining methods, together with hand-shoveling and ground-sluicing. The second papers deals with hydraulicking, sluice boxes and riffles, recovery of gold and platinum from placer concentrates, treatment of amalgam, and marketing of placer gold. The discussion of sluice boxes and subsequent subjects in the second paper applies to all forms of placer mining. The present paper treats of dredging and other forms of mechanical handling of placer gravels, and drift mining.

Jan 1, 1934

By ALBERT E. HALL, Arno C. Fieldner, Alexander L. Field

As a safeguard against excessive clinker troubles, specifications for the purchase of coal can be drawn to include the "softening" or "fusing" temperature of the ash. The value of such information has been recognized by the Bureau of Mines and has induced the bureau to investigab~ laboratory methods of determining the fUSIbility of coal ash, and the bearing of the results on clinker formation in fuel beds. The bureau realized that the fusibility of a mixture of oxides and silicates snch as is comprised in coal ash ,'aries according to the conditions under which tests are made, and that in the absence of any generally accepted method, no agreement is to be expected among tests made in differ«:-nt laboratories. Indeed, Marks a has recently called attention to differences as great as 3900 C. that were obtained with the same sample of ash by two different laboratories. Therefore if a fusion-temperature clause is to have any place in specifications for coal, a standard m('thod of t('sting should be adopted in order to insure comparable results by different laboratories and to obtain the softening or fusing temperature of the ash unde:'r conditions similar to those of a fuel bed. After a consistent method has been devised for obtaining comparable:' results at different laboratories, there will remain the correlation of these results with those from the burning of coal in furnaces before the value of fusibility tests in coal specifications can hE' finally determined.

Jan 1, 1918

By Donald H. Koch

The project investigated the impacts of coal and mineral storage piles on both ground and surface water quality. The study consisted of two major tacks, Task 1 had two phases. The first phase was field investigations in which ten cons and mineral stockpile sites (5 coal, 5 mineral: phosphate, lead, copper, iron, uranium) across the country were visited to determine the actual impart of coal and mineral stockpiles on writer quality. The second phase of Task I was a series of leaching experiments in which drainage from the ten coals and minerals was controlled and monitored to survey the extent to which storage piles release toxic ions to ground and surface waters. Task IT was n review of pollution abatement techniques with three generic treatment examples applied to lead-zinc ore, eastern coal, and uranium ore stockpile leachate. Major conclusions drawn from the completion of Tasks I and II include: water quality impacts are site specific, there is n high correlation between sulfide content of u material and its solution potential, and the selection of the best treatment alternative for n specific coal or mineral storage area must be based on site-specific criteria, pilot studies on representative leachate samples, and sound engineering design.

Jan 1, 1982

By George C. Branner

This circular is concerned with eight nonferrous scrap metals as they generated, collected, prepared, and consumed in California. Brief reference also is included with respect to Nevada and Hawaii. Four of these scrap metals - copper, lead, aluminum, and zinc - are of major importance and make up about 95 percent of the total value, whereas the remaining four - antimony, magnesium, nickel, and tin - make up the remaining 5 percent. For convenience, the subject matter is divided into three parts, (1) Data with respect to the collection, preparation, and marketing practices that are common activities to all the nonferrous scrap metals; (2) separate discussions and statistical data with respect to each of the eight nonferrous scrap metals in California; and (3) data with respect to Nevada and Hawaii.

Jan 1, 1962

By Hugo E. Camargo

Noise Induced Hearing Loss is the most common occupational disease in the U.S. and of paramount importance in the mining industry. According to data for 2006 from the Mine Safety and Health Administration (MSHA), Continuous Miner operators accounted for 30.2% of underground mining equipment operators with noise doses exceeding the Permissible Exposure Limit (PEL). This figure becomes more significant considering that 49% of the 2006 national underground coal production was extracted using continuous mining methods. Thus, there is a clear need to reduce the sound radiated by Continuous Mining Machines. The first step towards efficient noise control of a Continuous Mining Machine requires identification of the various noise sources under controlled operating conditions. To this end, a 42-microphone phased array was used in conjunction with 4 reference microphones to sample the acoustic field of a machine in the Hemi-anechoic chamber of the Pittsburgh Research Laboratory. These data were processed using a frequency-domain beamforming algorithm to obtain acoustic maps of 5 sides of the machine. The focus of the test was on the conveyor noise since previous studies showed that operation of the conveyor is the most important contributor to the sound radiated by the machine. From the acoustic maps, the following potential areas for noise control were identified, and included: chain-tail-roller interaction, chain flight tip-side board interaction, and chain-upper deck interaction.

Jan 1, 2008

By Robert W. Van Dolah

On December 27, 1961, a fire and explosion destroyed the blasting agent mixing plant and an attached storage barn of the Whitaker-Atlas Supply Co., near Norton, Wise County, Va. Five residences, an office building, four trucks, and three automobiles were completely destroyed; a house trailer and several other trucks and automobiles were severely damaged; and other property damage, including much window breakage, occurred up to 3 miles or more airline distance away. Through the quick action of the fire marshal of the Norton Fire Department, Norton, Va., there were no fatalities and only five persons required hospitalization. This incident is of particular interest because of the widespread practice of mixing fuel oil (FO) with ammonium nitrate (AN) to prepare low-cost blasting agents, in many cases under conditions and circumstances not very different from those presented here. A representative of the Bureau of Mines Explosives Research Laboratory, Pittsburgh, Pa., and field representatives of the Bureau's Health and Safety Activities conducted the investigation. Information in this report was obtained from representatives of the Whitaker-Atlas Supply Co., the Norton fire marshal, and others who were on the scene either shortly before or after the incident occurred. Representatives of the Manufacturing Chemists' Association, the Institute of Makers of Explosives, and individual ammonium nitrate producers participated in the inquiries and investigations.

Jan 1, 1962

By J. E. Fraley

Full-column anchored resin bolts were first used in underground mines in 1972. These bolts appear to improve support in many roof bolt applications, as indicated by the use of about 30 million resin bolts in 1980. In the mid-1970's, Bureau of Mines in-vestigators began looking for a substitute for resin because of its short supply and rapidly increasing price. The investigators selected accelerated gypsum plaster (CaSO. ·1/2H20), which becomes gypsum (CaSO.· 2H20) when mixed with water. Gypsum makes an effective alternate grout material because it hardens quickly, is readily available, and is inexpensive in comparison with other cementitious materials. The Bureau received a patent (U.s. patent 4,096,944) for a system combining water capsules (wax-encapsulated water) with plaster into cartridges resembling resin cartridges. This report presents the results of tests conducted by the Bureau on the plaster, the water capsules, and their combined use in cartridges. The tests were designed to determine how the gypsum-plaster water capsule bolting system performs and what happens in the hole while the bolt is being inserted through the cartridge. The test results indicate that water capsule plaster cartridges are a workable alternative to resin cartridges under normal or dry conditions.

Jan 1, 1987

By Virgil Marple

In the summer of 1979 the University of Minnesota Mobile Laboratory (UMML), designed for the analysis of airborne particles and gases was used to study fugitive dust from an open pit coal mine. The analysis consisted of determining the particle size distribution and concentration of dust from various mining operations, such as blasting, draglines, loading, roadways and bottom scrapers. For some operations the particles size distribution and concentrations were determined at varying distrances. Details of the dust concentration within the plumes as the plume passed the UMML were measured with an optical particle counter. For line sources, such as roadways this enabled the calculation of the particle flux at the sampling location. In addition to the standard instruments associated with the UMML, the applicability of some new instruments were investigated. These included a uniform deposit cascade impactor and a flux meter. Finally, a technique in identifying plume origins which utilized elemental X-ray flourescence analysis of filter samples was shown to be effective.

Jan 1, 1980

By Rudy J. Matetic

The National Institute for Occupational Safety and Health (NIOSH) at the Pittsburgh Research Laboratory (PRL) is conducting research to reduce the noise exposures of roof bolting machine operators and to prevent additional cases of Noise Induced Hearing Loss (NIHL) thru the development of engineering noise controls. This paper describes and evaluates an engineering noise control for the roof bolting machine, namely the collapsible drill steel enclosure. The results of the evaluation demonstrated that using the collapsible drill steel enclosure provided a 7 dB(A) reduction in sound pressure level at the operator?s position of a roof bolting machine.

Jan 1, 2008

By W. L. Cornell

The Missouri lead ores are the only domestic sources of cobalt presently being mined and processed for other materials. They represent the best short-term solution for meeting up to 13 pct of the Nation's strategic and critical cobalt needs from domestic sources. Presently, the cobalt is lost as an impurity in the copper, lead, and zinc concentrates and in the mill tailings because the technology to recover it with minium impact on present production does not exist. This paper presents results of research, built upon earlier Bureau of Mines laboratory research, to enumerate the problems encountered in cobalt recovery from the copper concentrate under actual mill conditions; to present alternative solutions to these problems; and finally, to describe the best available technology for cobalt recovery within the imposed constraints. Mineralogical analyses showed the cobalt present as a distinct mineral phase, predominately siegenite, amenable to a physical separation method such as froth flotation. Flotation was chosen for recovery because of easy adaptation by the mills. Unit processes of grinding, conditioning, and flotation were studied individually and in concert, and a series of continuous tests were run based on the parameters developed to obtain engineering data for subsequent economic analysis. Overall cobalt grades of 3.00 wt pct at a recovery of 64.0 pct were achieved.

Jan 1, 1987

By R. E. Zane

[The Northwest Experiment Station of the Bureau of lines, in cooperation with the College of Mines, University of Washington, has completed a detailed investigation of the physical and chemical properties of western cokes made or used in the Pacific Northwest, as evaluated by standard methods. 4/ One of the chemical properties determined, to which more or less importance has been attached, was reactivity or combustibility. As no standardized procedure is available, it was necessary to develop a workable method for evaluating this property. The combustibility of coke is usually measured by the formation of carbon dioxide with time at a particular temperature or by the reduction of carbon dioxide to carbon monoxide. Analysis of the resulting gases commonly is required to evaluate the result. The method described in this paper is simple and direct in that the sample of coke or other carbonaceous material is weighed as it burns; the loss in weight and time is indicated by a balance and clock arrangement. Gas analyses are not rewired. Methods similar in principle have been used by Tu, Davis, and Hottel6/ and by Oshima and Fukuda7/ for determining the combustion rate of carbon and for studying the effect of ash on combustion characteristics. Both methods: are more elaborate in procedure and apparatus required than teat described here. Brief the method comprises burning a sample of coarsely grained. coke or]

Jan 1, 1940

By William A. Stickney

The zirconium-hafnium separation plant at Albany, Oreg., was the result of a chain of events that started with studies by A. R. Kaufmann at the Massachusetts Institute of Technology. Variations in the listed neutron-absorption cross-section of zirconium caused him to suspect a misprint. As a result of these discrepancies and following his suggestions, Oak Ridge scientists made studies establishing a value of 0.4 barn or lower. This meant that the potential of zirconium for reactor application was greatly enhanced. Since hafnium is invariably associated with zirconium and has a high neutron cross-section, it was necessary that an efficient hafnium-separation method be developed before the superiority of zirconium as a structural material in nuclear reactors could be realized. The Albany plant was built and operated for the Atomic Energy Commission (AEC) under Letter Agreement AT-(11-1) -140, patterned after a plant operated by the Carbide and Carbon Chemicals Corp. at Oak Ridge, Tenn. Construction was begun in April 1951. Hafnium was to be extracted preferentially as hafnium thiocyanate from an aqueous mixture of zirconyl and hafnyl chlorides in hexone (methyl isobutyl ketone) by a liquid-liquid countercurrent system.

Jan 1, 1959

By Louis Schaffer

A literature review concerning dredging hazards and dredge safety practices and an examination of MSHA accident and injury statistics on dredge mining in the United States provided the background for an analysis which was completed by visiting 31 dredge operations, dredge manufacturers, and dredging experts. The principal hazards are discussed and countermeasures are suggested in several areas. Drowning is the single largest fatal injury category. Special emphasis is given to the design, care and use requirements of personal flotation devices.

Jan 1, 1984

By Ronald W. Stingelin

The geology of the roof of the Pittsburgh coal bed was studied and mapped in nine contiguous counties containing the bulk of the remaining reserves of this coal bed in the northern Appalachian Coal Basin. Drill core records from Belmont and Monroe counties, Ohio, Washington and Greene counties Pennsylvania, and Ohio, Marshall, Wetzel, Monongalia, and Marion counties, West Virginia provided the data for twelve computer generated regional geologic variable maps. Four of these geologic variables (overburden thickness, vertical distance to the rider coal, lithology at the five foot horizon above the roof of the mineable Pittsburgh seam, and the number of lithologic changes within the 30 foot interval above the roof of the mineable Pittsburgh seam) were used to estimate the risk of potential roof falls by a methological scheme developed during this study. A hazard zone risk map was developed showing a generalized regional trend of increasing risk from west to east across the basin. Mapping of individual geologic variables and mapping of hazard risk can be done at any scale. The accuracy of the mapping is primarily dependent on the density of the drill core records. Geologic feature maps and the hazard risk map contained in this report are reduced (1 :500,000 scale) versions of the larger scale (1 :62,500) maps prepared for the Bureau of Mines as map folios.

Jan 1, 1979

By John C. Machisak

This publication, for the calendar year 1959, contains statistical data on injuries and employment pertinent to metal mines, ore-dressing plants, and primary nonferrous smelters, refineries, and reduction plants. The Bureau of Mines is authorized to request data on injuries and employment in the metal-mining industry, and the information, voluntarily submitted by the operators, contributes immeasurably to the promotion of safety in the metal-mining industry. Every effort has been made to make the annual canvass as complete as possible. The data presented are classified according to the hind of ore mined and includes information on copper, iron, lead-zinc, gold-silver lode, placer, uranium- vanadium, and miscellaneous metals. A breakdown of miscellaneous metals by commodity is shown in tables 17 and 18.

Jan 1, 1963