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By Ren G. Dong, Kristine M. Krajnak, Dan Welcome

Continual occupational exposure to vibrating hand tools can damage the neural, vascular and other soft tissues of the fingers. Rat tail models have been developed to investigate the biological responses of the tissues to vibration.1-2 However, the biodynamic response of the tail relative to that of the human fingers has not been characterized. The objective of this pilot study was to compare the transmissibilities of rat tails measured via a scanning laser vibrometer to those of human fingers gripping a handle. Methods In Part I of this experiment, four male Sprague Dawley rats (6 weeks old) were exposed to discrete 5g-rms sinusoids of 32, 63, 125, 160, 250, and 500 Hz. The rats were restrained in Broome-style restrainers with their tails constrained without compression to an exposure platform via elastic straps as shown in Figure 1. The platform was attached to a vertically vibrating shaker. The vibration was measured for the array of points shown in Figure 1 using a scanning laser vibrometer (Polytec) and the transmissibility calculated for each point on the tail relative to the reference points on the platform. In Part II, three male human subjects were exposed at the frequencies specified in Part I - with the addition of 1000 Hz - at a magnitude at the ANSI <0.5-hr limit up to 63 Hz, after which the acceleration was held constant at 5g-rms. The subjects gripped an instrumented handle at 20 N as shown in Figure 2. The transmissibility was calculated relative to the reference points on the handle. [ ]

Jan 6, 2006

By J. S. Stachulak, G. H. Schnakenberg

The objective of the Diesel Emissions Evaluation Program (DEEP)-sponsored project at Inco&apos;s Stobie mine was to conduct a long term field evaluation of diesel particulate filter (DPF) systems available to the underground mining industry. Some of the major issues studied were criteria for selecting the filter media, means of DPF regeneration, efficiency of DPF systems and the occurrence of unwanted secondary emissions, and reliability and durability of DPF systems. Nine state-of-the-art diesel particulate matter (DPM) filtration systems have been retrofitted to heavy-duty and light-duty vehicles and have been subjected to extensive long-term in-mine evaluation. Periodic efficiency tests were conducted at various stages of the study (2001, 2002 and 2004) to establish in-use efficiencies and durability of the tested DPF systems. The results were used to assess the effects of the filter systems on the concentrations of particulate matter, nitric oxide, nitrogen dioxide and carbon monoxide in the vehicle exhaust. The variety of filtration systems and regeneration concepts used in this study offered the opportunity to investigate their advantages and disadvantages. This paper also offers a review of selected experiences with the installation and operation of the DPF systems on underground mining vehicles at the Inco Stobie Mine.

By G. L. Oldright, F. S. Wartman

"In the process of smelting copper ores and secondaries in the reverberatory furnace to produce a copper matte and a slag low enough in copper content to be discarded on the dump, it is essential to the best functioning of the process that most of the iron in the material charged into the furnace be at the end in the form of sulphide in the matte or ferrous oxide in the slag. Ferric oxide and magnetite present in the charged material should be reduced to ferrous sulphide or oxide. Ferric oxide offers no difficulty in reduction, at least to the magnetite stage, because it reacts very readily with sulphides at quite low temperatures. Magnetite is less reactive and consequently more resistant to slagging, so that the furnace man must take advantage of all factors favoring its reduction in order to prevent accumulations in the furnace.In order to determine these factors more definitely, the Bureau of Mines in cooperation with the Department of Metallurgy, University of Arizona, has undertaken at the Southwest Experiment Station an investigation of the effect of various factors upon the rate of reduction of magnetite by ferrous sulphide. A previous paper's reported the nature of the reactions taking place and the effect of various physical factors when only pure sulphide and oxide were present. Since in the actual smelting operation, many other substances are also present, it seemed desirable to make a study of the effect of their presence upon the rate of reduction of magnetite by ferrous sulphide. Such a study has been made; the work done and the results obtained are described herewith.As will be shown later, it has been found that of the substances usually present in the smelting charge, silica and magnesia accelerate, whereas lime, alumina, and cuprous sulphide hinder the reduction of magnetite by ferrous sulphide.No report of a previous laboratory investigation of this subject has been found. Almost all furnace operators have made at one time or another at least qualitative ccmparisons of the effect of various changes in operating oonditions upon the behavior of magnetite in the furnace, but the conclusions derived from the experiments have never been published."

Mar 1, 1931

By Russell E. Griffin

The current state-of-the-art of fire and smoke detection technology is reviewed from the standpoint of suitability for use in underground metal and nonmetal mines. Detection modes, fire signatures, and environmental considerations are included. Preliminary results of long-term in-mine tests are presented.

Jan 1, 1979

The general nature of the special constructional features that are required to provide safety from explosion hazards on machines approved as permissible by the Bureau of Mines is fairly well known to mining men who are at all interested in safety. These requirements are outlined in the schedules, under the provisions of which the investigations of such machines are conducted. Also, the method of conducting inspections and. tests of such machines has been described in Bureau of Mines Bulletin 305, Inspection and Testing of Mine Type Electrical Equipment for Permissibility, published in 1929. A more detailed knowledge of the special safety features of a particular machine is often useful and sometimes essential for inspectors, safety engineers, maintenance men, and engineers in selecting machines for a particular application. Three bulletins that give information of this nature have been published by the bureau, viz., Bulletin 313, Permissible Storage-Battery Locomotives and Power Trucks. Bulletin 343, Permissible Coal-Handling Equipment. Bulletin 382, Permissible Coal-Cutting Equipment.

Jan 1, 1937

By R. V. Ramani

One area of study in the Coal Mine Injury Analysis project was to illustrate and enhance the ability of mine safety management personnel to apply analytical techniques to injury experience data and to justify requests for funds for safety enhancement actions on a cost/benefit and other quantitative basis. Four volumes of this final project report detail (1) the objectives and scope of the mine safety management research, (2) the results of literature review, and case studies, and (3) models developed for mine safety management. The four volumes are titled as Volume III: Mine Safety Management, Volume IV: Analytical Techniques for Mine Safety Management; Volume V: Mine Safety Management Case Studies and Volume IX: Training Cost Model. In this volume, the quantitative procedures that have been developed for the mine-specific analyses of accident/injury experience data are presented and their applications are demonstrated in a summary form through case study examples. The quantitative procedures will aid mine safety management personnel to develop focused accident prevention strategies including training, as well as to justify the investment in such proactive programs through cost-benefit analyses.

Jan 1, 1993

By L. A. Neumeier

The Bureau of Mines evaluated creep properties of Zn-Cu-Ti alloys that were annealed after finish-rolling either cold) or at 480° F (249° C). Compositions ranged up to 1.25 pct Cu and 0.36 pct Ti. Most data are for sheet annealed after finish-rolling to 92-pct total reduction. Annealing times were varied at temperatures between 320° and 560° F (160° and 293° C). For a number of the alloys, annealing after hot-rolling at 480° F affects creep properties very differently in longitudinal and transverse sheet directions. The detrimental result is that the anisotropy in creep properties between the two directions can be vastly increased. Conversely, specific annealing treatments of certain heavily cold-rolled alloys result in surprisingly low anisotropy in creep properties and the low anisotropy coincides with excellent creep resistance for both directions. Supplemental data are presented on tensile, hardness, and thermal expansion properties, and microstructures.

Jan 1, 1972

By David S. Yantek

Miners in underground coal mines experience prolonged exposure to high noise levels, often with A-weighted sound levels in excess of 90 dB. Field tests have shown that the continuous miner conveyor is a dominant noise source. This paper will identify the most significant noise-radiating surfaces on the continuous miner tail section using vibration levels and surface areas to estimate the sound power levels of each surface. In addition, using five test cases, this study will examine the effects of three engineering noise controls on the surface-averaged vibration levels and average sound levels measured with four microphones located two meters from the tail section. The noise-radiating surfaces of the conveyor’s tail section include the top and bottom decks, the sideboards, and the flex plates. Emphasis is placed on the changes in the estimated sound power levels in the 500 – 2500 Hz 1/3-octave bands since this frequency range accounts for 80-85% of the sound energy near the tail section. The results show that the bottom deck is the most significant noise radiator for the untreated miner. Installing a coated bottom deck reduces the estimated sound power level radiated from the bottom deck by 11 dB and the average sound level by 2 dB. Using a coated tail roller results in reductions of the estimated sound power levels for individual components from 1 to 4 dBand reduces the average sound level by 2 dB. Coating the slide plate has little effect on both the estimated radiated sound power levels and the average sound level. The test results indicate that modifications that reduce flex plate vibration and reduce energy transfer from the tail roller into the tail section will be effective in reducing noise when combined with a coated tail roller and coated return deck.

By C. A. Geffen

This report, sponsored by the U. S. Bureau of Mines, presents the results of an examination of the safety of the impactor shaft sinking system in comparison to conventional shaft sinking technology. Detailed study of the impactor system was also performed to identify and recommend design changes for optimum safety conditions. A comparison of the impactor machine and its support systems with conventional shaft sinking was made on the basis of relative risk levels. Risk incorporates measures of both the frequency and the potential consequence of accidents. A safety evaluation of the com¬ponent operations of the impactor shaft sinking system was performed using a Failure Modes and Effects Analysis (FMEA) methodology. The results of this analysis show generally that the impactor shaft sinking system is safer than conventional shaft sinking. The potential risk of conventional shaft sinking operations could be reduced by an average of over 35 percent with use of the impactor shaft sinking system. Design change recommendations to further improve the safety of the impactor system include a revised fire suppression system, improved access to and from the operator cabs, reliable noise attenuation measures and improved communication systems. An operational safety manual was also developed for the impactor shaft sinking system.

Jan 1, 1982

By R. H. Grau, S. B. Robertson, R. B. Krog, T. P. Mucho

Due to the difficulties of ventilating large opening stone mines, the effective dilution of diesel particulate matter and noxious gases has often been problematic. Since stone mines have large openings that develop low air resistances, and propeller fans are designed for low pressure-high volume applications, main mine propeller fans may be a feasible option for ventilating underground stone mines. This paper describes the results of a case study where researchers from the National Institute for Occupational Safety and Health have demonstrated that significant increases in total mine airflow can be achieved and the ventilation improved in a large-opening stone mine by replacing an axial-vane mine fan with two 12-ft diameter propeller fans and adding a line of stoppings. In this study, the use of the propeller fans more than doubled the air quantity from 300,000 cfm to 750,000 cfm, while operating at 50 horsepower less than the original axial-vane fan.

By W. A. Calhoun

This report gives results of metallurgical investigations performed by the Bureau of Mines on mineral samples taken during April 1959, from Hawaiian bauxite deposits on the islands of Kauai, Maui, and Hawaii. The bauxite samples were tested at the Bureau&apos;s Rolla Metallurgy Research Center, Rolla, Mo., to determine if alumina could be extracted. The results were encouraging. Extraction of the alumina by the American Bayer type digest of crude ore samples from Kauai, Maui, and Hawaii recovered 78.8, 73.1, and 70.0 percent, of the total alumina, respectively. These recoveries were increased to 82.8, 85.5, and 79.5 percent by modifying the treatment, which consisted essentially of calcination and weak caustic desilication to provide a residue. The residue was then treated with calcium oxide and digested in a strong caustic solution to extract the alumina.

Jan 1, 1962

By Nicholas Kyriazi, John P. Shubilla

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory, has undertaken a study to determine how well self-contained self-rescuers (SCSRs), deployed in accordance with Federal regulations (30 CFR 75.1714), hold up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSRs in the sixth phase of testing from mid-1996 to early 1998. The SCSRs were tested on human subjects and on a breathing and metabolic simulator. These results indicate that most of the apparatus, if they pass their inspection criteria, perform satisfactorily. However, the deployed CSE SR-100s exhibited significantly higher inhaled CO2 levels than new units, as in the previous phase. This will cause higher ventilation rates in most users, which will, in turn, result in higher breathing pressures, possibly causing users to prematurely remove the apparatus. CSE Corp. has developed a noise test that can identify apparatus suffering from chemical-bed degradation causing the early CO2 breakthrough. This test was added to the inspection criteria for the SR-100. In addition, several of the MSA Portal-Packs that passed their inspection criteria were found to have KO2 dust in their mouthpieces. Further investigations by NIOSH and the Mine Safety and Health Administration confirmed these findings, which resulted in the decertification of the apparatus and their removal from service.

Jan 1, 2000

By R. G. Gürtunca, J. A. Breslin

This paper briefly describes the progress in mine safety in the United States, with emphasis on recent events that have followed since the explosion at the Sago Mine in January 2006. Legislation following the mine accidents last year and areas of work carried out by the National Institute for Occupational Safety and Health (NIOSH) related to the accidents are discussed. American coal production in 2006 was 1,150 million short tons. Most of this coal is consumed domestically, with annual exports of coal about 50 million tons. One third of annual production is produced at surface mines and the rest from underground. This coal is produced by about 82,000 miners working at 1,400 coal mines. Major improvements in coal mine safety have been made in the US since the Federal Mine Safety and Health Act of 1977. The fatal injury rate in underground coal mines between 1977 and 2004 was reduced by 47.8% to 0.036. The annual number of fatalities dropped from 112 to 14 during that period. Likewise, the non-fatal days-lost injury rate was reduced by 42.6% from 10.87 to 6.24. The improvements in mine safety during this period can be seen in the graph of underground coal mine explosion fatalities and injuries from 1980 to present, which is shown in Figure 1. Between 1984 and 1993 (9 year period) there were 5 explosions and one major mine fire, for a total of 55 fatalities. Over the seven year period from 1993 to 1999 there were no fatalities from coal mine fires and explosions. However, in the six years since 2000 there have been 5 explosions and one fire, which have caused 37 fatalities. [ ]

By J. Bennetts

As part of its mission to develop technology that will help increase the supply of critical and strategic minerals from domestic resources, the Bureau of Mines has investigated methods for beneficiating platinum-group metal ores from the Stillwater complex, Montana. This report presents the result of a bench-scale study employing froth flotation to recover a sulfide concentrate containing platinum-palladium values from a mineralized gabbro. Best results were obtained with a flotation scheme utilizing a mercaptobenzothiazone collector and sulfuric acid. Rougher concentrates containing approximately 11 oz Pt-Pd/ton and 90 pct of the metal values in the ore were obtained. Subsequently, cleaner concentrates containing approximately 26 oz Pt-Pd/ton and between 80 to 85 pct of the Pt-Pd values in the ore were prepared.

Jan 1, 1980

By M. Hertzberg

Results of a comprehensive study of the absolute spectral radiance of the infrared emissions from methane-air explosions are reported. The spectral growth of these expanding flames were recorded with a time resolution of 1 msec in the spectral range of 1.7 to 5.0 µm. Time-resolved spectra were obtained for methane-air mixtures as a function of stoichiometry, nitrogen dilution, and Halon dilution, in a 9-liter vessel under different venting conditions. Data are also presented for coal dust-air explosions. Temperatures, obtained from the absolute radiances and from a band ratio technique for methane-air, are internally consistent and are generally 50° to 200°K below adiabatic flame temperatures. All near limit mixtures gave essentially the same flame temperatures (1,500° to 1,600° K) regardless of whether the limit was obtained by dilution with excess air, excess methane, excess nitrogen, or Halon. The coal dust explosion spectrum is essentially a blackbody continuum at 1,500° K with some selective emission at 4.4 µm from hotter CO2. The data are analyzed in terms of the radiative dynamics of a sperically expanding flame zone. The importance of radiative transport is assessed. An equation is derived which relates the instantaneous fraction of combustion power radiated to adiabatic variables.

Jan 1, 1973

By M. L. Bowser

Pulse-forming circuitry is described for use in explosives research that requires precise synchronization and control of events in order to investigate detonation parameters. Included are pulse generators for oscilloscope sweep control, counterchronograph actuators, and a raster-type oscillographic method for the determination of velocities of detonation that are applicable to studies on solid, liquid, and gaseous detonations. INTRODUCTION Prom time to time, requests have been received for information on electronic circuitry used in explosives work at the Explosives Research Laboratory, Bruceton, Pa. The methods used are not entirely original;4 5 6 however, modifications of earlier techniques and some novel design aspects have resulted in time-tested methods that warrant a more detailed description.

Jan 1, 1962

By Candice Stevens

The Territory of Afars and Issas is to receive its independence from France on June 27, 1977. The Territory&apos;s economic income was based on entrepôt trade through the port of Djibouti and trans-shipment of goods on the Chemin de Fer Franco-Ethiopian (CFE) railroad. The Territorial budget was scheduled to in- crease from $32.6 million3 in 1976 to $36 million in 1977, despite severe shortfalls in 1976 stemming from inflation and a persistent balance-of-trade deficit. Subsidies from France continued to sustain the economy, and the French pledged to provide approximately $140 million in aid annually after independence. In 1976, financial agreements were concluded with a number of Arab oil-producing countries, including Saudi Arabia which granted $10 million toward development projects. The new Republic of Djibouti is scheduled to become the 49th member State of the Organization of African Unity (OAU) and the 21st member of the Arab League, and to receive aid from their financial institutions. The port of Djibouti and the CFE railroad constituted the Territory&apos;s main economic resources. Traffic at the port greatly

Jan 1, 1980

By Kevin Connor

There was little change during 1988 in the production of minerals in Burundi. The Government of Burundi, which banned all commercial mining operations in the country in 1979, lifted the ban on mining of alluvial gold deposits and started a program of small-scale artisan gold mining in October. Along with the legal mining of gold, licensed gold trading counters were established. Other mineral commodities produced were kaolin clay, lime, and peat. In compliance with the Government ban, the only mineral wealth exploited for commercial sale and export was alluvial gold. Through financial assistance from the International Bank for Reconstruction and Development (World Bank) and the United Nations Development Program (UNDP), a study to inventory the country&apos;s mineral resources continued throughout the year. As part of this study, during the year, a West German company undertook a drilling program to further outline the nickel reserves of the Musongati area in central Burundi. Results of the work as of yearend were disappointing, with only 12 million tons of ore identified with better than 2% nickel content proven. Investigations also continued during the year regarding the centrally located deposits of vanadium-bearing titaniferous magnetite. A Norwegian company contracted to prepare a prefeasibility study for developing the deposit. The British Sulphur Corp. Ltd. was nearing completion of its $1.2 million2 study of the phosphatic limestone deposit at Matongo-Bandaga at yearend. Ore reserves of about 17 million tons grading 11% phosphorus pentoxide (P2O3) had been identified. The phosphate zone overlies a carbonatite rock, which could provide the basis for a cement industry. Additional drilling was planned for 1984. Exploration for gold was underway in 19S3 in northern Burundi through UNDP funding. Several primary deposits of shallow semimassive sulfides with gold values ranging from traces to 11 grams per ton had been discovered. With assistance from the Federal Republic of Germany, bastnasite reserves of 5,400 tons, with associated high europium oxide and cerium content, were verified, and the prospects for finding

Jan 1, 1985

By E. Shekarchi

A year after the Soviet Union invaded Afghanistan and replaced President Amin with their choice, President Karmal, Afghanistan remained in turmoil. In some respects, the political and economic situation in Afghanistan was no better by the end of 1980 than it was preceding the December 1979 invasion. The Government faced widespread and growing alienation and resistance, virulent factionalism within the ruling party, and an acute shortage of material. The mining sector of the country did not fare better either; the only raw material produced in a significant amount was natural gas, which was exported mainly to the Soviet Union. No statistics on production of other minerals and materials were available by yearend. Most of Afghanistan&apos;s gas production was from the Hodja-Gugerdag Field, southeast of Shibarghan. The gas flow from this field had been about 300 million cubic feet per day since 1961. An estimated 230 to 250 million cubic feet per day of Hodja-Gugerdag&apos;s production was moved by pipeline across the Amu-Darya River into the Soviet Union. Most of the remainder was transmitted eastward to a 105,000-ton-per-year fertilizer plant and an electric power station built near Mazar-i-Sharif with Soviet assistance. After the Soviet invasion, the second gasfield, Djar-Kuduk, in the Shibarghan area, was brought under production. This field, which will produce about 200 million cubic feet per day, consists of four gas zones in the Jurassic and lower Cretaceous zones between 3,000 and 8.500 feet deep. The gas has a high hydrogen sulfide content, with considerable carbon dioxide, A new treatment plant was built at Djar-Kuduk by Soviet technicians under a turnkey contract at the end of 1980. It is believed that most of the Djar-Kuduk&apos;s initial flow will be sent to the Soviet Union.

Jan 1, 1982

By D. J. Dollhopf

This research was part of an effort to investigate means of reestablishing non¬polluted hydrological systems in areas where surface mining directly impacts shallow ground-water resources. Chemically undesirable overburden material was selectively backfilled with the intent that it would be below the future root zone, be above the reestablished aquifer, and would not be leached as a result of deep percolation. After 2 years the buried material remains above the spoil aquifer and below the maximum rooting depth. Unsaturated water flow from the land surface to the buried material occurred during wet climatological periods. No significant leaching of buried material was observed, however. Overburden sample contamination from drill stem joint grease with Pb, Zn, and Cu additives caused substantial error regarding DTPA extractable trace metals. A grease with teflon and talc additives was recommended for use in future sampling programs. DTPA extractable trace elements in overburden material had no statistical relationship to post-mine ground-water quality. Overburden columns leached with water produced leachates comparable to overburden and spoil ground-water trace metal quality. A depositional model described the Rosebud Coal overburden as a fluvial system with distinct units of sand, silt, and clay, with distinct chemical properties. Physical and chemical characteristics of the model were comparable to the in situ geochemical system, a relationship which may aid in locating overburden materials unsuitable for reclamation.

Jan 1, 1979