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By Harold W. Lipper

A NEW record was set for helium shipment in 1962 for the 13th successive year. For the first time since 1949, the production of helium from natural gas at Bureau of Mines plants was less than in the previous year. The Bureau shipped 599.5 million cubic feet, 9 percent more than the 1961 volume, and produced 680.9 million cubic feet-a decrease of 6 percent from the record set in 1961. The Bureau added 77.2 million cubic feet to the volume stored for future use. Of the total 524.6 million cubic feet in storage, 522.4 million cubic feet is accumulated excess production from Bureau of Mines plants. The remaining 2.2 million cubic feet was purchased during 1962 from industry under the helium conservation program. The first two of five private plants began production in December to recover helium for conservation storage and ultimate use. A 425-mile pipeline system to transport helium from the five private plants to the Cliffside field was constructed by the Bureau at a cost of about $8 million.

Jan 1, 1963

By Thomas V. Falkie, R. Venkataramani

Hand portable truck axle scales were purchased from the Martin¬Decker Company, Santa Ana, California, for weighing the rubber-tired mine shuttle cars. The scales consisted of two hydraulic load-pads, measuring 4" thick, and 21" long by 13" wide at the pad surface and one totallizer-dial indicator unit. The development of a technique to install the scales effectively for shuttle car-weighing followed an evolutionary process. The setup which finally proved to be effective entailed countersinking and level¬ling the load pads in the floor on the shuttle car trackway such that the tops of the pads were three inches below the floor level. A plat¬form consisting of two braced side-by-side 3" x 8" lumber planks was made. The platform was placed across the load pads with six inches of overlap on each side to provide room for imperfect tracking of the shuttle car. Additionally, 3" x 8" lumber planks were imbedded across the runway immediately behind and ahead of the platform. These auxili¬ary planks were firmly braced into the floor by vertical posts or jacks set against the roof; the planks constituted a stable approach platform to enable the shuttle car to roll unimpeded onto the scale platform in either direction of travel. Figure 22 shows this arrangement in detail. The setup of the scales was done during non-production hours prior to the first working shift of the week. This task took seven to twelve hours with two men. During the actual weighing experiment, the following limitations were realized. 1. Delays will be introduced into the cycle of operations because the shuttle cars must be stopped and positioned on the platform. However, these delays can be held to a minimum, time wise, as the

Jan 1, 1972

By R. V. Ramani, A. S. C. Owili-eger

This report was prepared by The Pennsylvania State University under USBM Contract No. G0111808. The contract was initiated under the Coal Mine Health and Safety Program. It was administered under the technical direction of DMSE, with Mr. G. R. Schottler acting as the technical project officer. Mr. J. A. Herickes was the contract administrator for the Bureau of Mines. This report is a summary of the work recently completed as part of this contract during the period June, 1971 to December, 1973. This report was submitted by the authors on March 31, 1974. Part of the research reported here was originally done on a grant from the Department of Environmental Resources, Commonwealth of Pennsylvania and reported in Special Research Report No. SR-95 (February 25, 1973) of the Coal Research Board, The Pennsylvania State University.

Jan 1, 1974

By Steven E. Mischler

The exposure of mine workers to diesel particulate matter (DPM) and gases is an issue of great concern to the underground mining community in the United States. Approximately 30,000 underground miners are potentially exposed to high concentrations of DPM. In January of 2001, the U.S. Mine Safety and Health Administration (MSHA) promulgated rules setting compliance standards for both underground coal and metal / nonmetal mine workers. As industry works to achieve compliance with these standards, mine operators are looking for feasible methods for reducing DPM concentrations in their mines. In addition, the industry needs methods to accurately measure DPM to ensure that the control strategies they adopt are working successfully. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) conducts research to evaluate control technologies and monitoring instrumentation that can be used to reduce the diesel particulate matter (DPM) exposure of mine workers. An overview of the strategies being utilized in underground US mines to reduce DPM concentrations will be presented. Also, updates on the development of diesel monitoring instruments such as the continuous elemental carbon monitor or the Personal Dust Monitor for DPM measurement will be provided.

Jan 1, 2010

By Jr. Zipf

Highwall mining is an important surface coal mining method, and it may account for approximately 4% of total U.S. coal production. Highwall stability is the major ground control related safety concern. Ground control plans for highwall mining should specify hole width, web pillar width, barrier pillar width and number of holes between barriers. This paper offers simple design charts for these parameters aimed at providing “ball park” checks. Web pillars containing pre-existing auger holes are analyzed and a design chart for estimating their minimum width is also presented. Finally, close proximity multiple seam highwall mining, which may have caused several serious highwall failures, is analyzed. Web and barrier pillar recommendations for this special situation are presented.

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Haiti has been prepared from the best available information in Washington, but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State .

Sep 1, 1930

By J. C. Edwards

Fire experiments were conducted in the Safety Research Coal Mine (SRCM) at the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, with coal, diesel-fuel, electrical-cable, conveyor-belt, and metal-cutting fire sources to determine the response of fire sensors to products-of-combustion (POC). Metal oxide semiconductor (MOS) and smoke fire sensors demonstrated an earlier fire detection capability than a CO sensor. This capability was of particular significance for a conveyor-belt fire in which the optical visibility was reduced to 1.52 m with an increase in CO of less than 2 ppm at a distance of 148 m from the fire. Application of a neural-network program to the sensor responses from each type of fire source resulted in correct classifications of coal, diesel-fuel, cable, belt, and metal-cutting combustion with a mean of 96% of the test data correctly classified.

Jan 1, 2000

By V. A. Marple, K. L. Rubow

"IntroductionA particle dispersion system has been developed to aerosolize bulk powders or material deposited on surfaces such as filters. The size distribution of the aerosolized particles can then be obtained by sampling the particles with an aerosol sizing instrument such as a TSI aerodynamic particle sizer (APS) or a cascade impactor.Of particular interest is the applicability of using this technique to obtain the size distribution of particles collected on filters. This system has been used to determine the size distribution of coal dust particle collected on membrane filters. The use of this device in this application is quite intriguing in that, if this technique can be shown to accurately determine the size distribution of airborne particles, one can easily collect particle samples using either personal or area particle samplers, determine the mass concentration of the collected material through gravimetric techniques and then use the particle dispersion system coupled with the APS to determine the particle size distribution. With this technique one can determine the particle size of dust in environments, such as underground mines, where it would be inconvenient or impossible to use a particle sizing instrument.Particle Dispersion SystemA prototype particle dispersion system has been developed for aerosolizing particles. A schematic diagram of the system is shown in Figure 1. The system consists of mechanism for advancing the particle sample beneath a dust pickup tube, a venturi for deagglomerating the particles, and a instrument for analyzing the aerosolized particulate matter.The procedure to analyze a particle sample is as follows. The particles to be aerosolized are placed on a sample plate from where the particles are picked up by an air stream flowing upward in a small capillary tube (dust pickup tube). This tube operates as a small vacuum cleaner passing over the sample plate. The air is drawn up the capillary tube at a rate of 2 L/m by a venturi aspirator. This is accomplished by placing the outlet of the capillary tube near the throat of the venturi. The accelerated velocity of the air creates a low pressure in this region which draws flow up the capillary tube. From the outlet of the capillary tube particles are transported to the inlet of the APS where a small fraction are sampled and the aerodynamic diameter of the particles determined. The particles which are not measured by the APS are passed into a HEPA filter."

Mar 1, 1989

By J. F. Barkley

"A knowledge of the carbon dioxide (002) content of the products of combustion, particularly from the boiler furnace, is very valuable. An instantaneous indication of the CO2 can be used as a useful guide to efficient burning. A permanent record over a. period of time gives a story to the management which tends to keep the operators more alert. Many instruments that indicate and record CO2 have appeared within the last fifteen years. More are about to appear. Although simple principles involving chemical, physical, or electrical qualities, are being used, there is at present a general feeling of uncertainty about such instruments in the boiler room any instruments are bought, run awhile, then lie idle indefinitely.Inquiries as to CO2 machines continually come to the Bureau of Mines from the general public, as well as from other branches of the Government. Some ten years ago a series of tests was made on certain instruments at that time on the market. The following test was made quite recently on four of the newer types, including one using an electrical principle. The four instruments were installed on one boiler each, according to the instructions of the makers, and the recommended routine attention was given them. The test was of a service nature duplicating the conditions under which the instruments ordinarily serve. The boiler that was available for this purpose was practically banked for some hours of the night. This caused the average CO2 for the entire twenty-four hours to be rather low, although it reached the higher ranges of the instruments during the day.Each day the charts were averaged and the results plotted to form the accompanying curve. The record of each instrument is shown by its particular mark, the dot, circle, cross and square being used in addition there is plotted for each day a rectangular area representing 1 % CO2 in height. The proper positions of this area was determined by means of the Crsat. Where the plotted point for an instrument falls within the rectangel its accuracy is within 1/2% CO2, which is considered satisfactory. Where it falls outside the rectangle, inaccuracy is indicated."

Mar 1, 1925

By E. J. Gleim

During the past 10 years the Bureau of Mines has had a broad experience in the tasting and inspection of electric motors for gaol-cutting machines, cowl drills, storage-battery locomotives and other equipment Which is used in mines where explosive mixtures of methane and air may be encountered. From this experience the Bureau's engineers have reached the conclusion that the most satisfactory method of protecting a motor so as to prevent any sparks resulting from rough commutator, loose contacts or short-circuits in it, from igniting he surrounding atmosphere, is to totally inclose the motor with a substantial casing; having flanged joints. These joints should be metal-to-metal contact so that the shortest path from the interior to the exterior Of the casing is not less than one inch in length. On account of this experience with mining machinery, the Bureau has been asked whether an equal or loss degree of protection would be sufficient for motors for service in or about places such as refineries, gasoline filling stations, cleaning establishments and pumping stations, or in any place where there is liklihood of explosive mixtures of gasoline or naphtha vapors and air accumulating.

Jan 1, 1922

By R. Hogg

"Some basic features of the science and technology of particle systems are reviewed in the context of agglomeration processes. Emphasis is placed on the force of interaction among particles and with their environment and on their dependence on particle characteristics and interfacial phenomena. The complex role these forces play in the various stages of agglomerate formation, growth, consolidation and structure development, and their influence on final product properties is discussed.INTRODUCTION Agglomeration is an example of a process where the technology has generally preceded the science. Process development• has very often been by trial-and-error albeit with an eye on some basic principles. Nevertheless there is' a scientific basis to the process and a better understanding of the fundamentals can surely lead to improvements in process design and control.Successful processes for the agglomeration of fine particles depend on proper control of the adhesional forces between particles, to encourage agglomerate formation and growth and to provide adequate mechanical strength in the product. At the same time the rheology of the particulate system can be critical to the rearrangement of particles necessary to permit densification of the agglomerate and the development of an agglomerate structure appropriate to the end-use requirements.AGGLOMERATION SYSTEMSUltimately, the performance, of any agglomeration process depends on the• characteristics of the particles and their environment. The specific effects, however, are often complex and may be very difficult to pinpoint by simple observation of the process. A typical agglomeration process involves a number of concurrent or consecutive steps - adhesion, growth, compaction, etc., - each of which is affected by the characteristics of the system, but not necessarily in the same way. The effect of particle size, say on agglomerate growth may be quite different from its effect on compaction and its optimum value may differ widely from one stage to the other. Obviously there.is a general need for compromise in the design and operation, of agglomeration systems. Furtnermore, an understanding of the details of the process and their complexities can be critical to process optimization and improved product quality control."

Jan 1, 1989

By Charles D. Litton

Laboratory experiments were conducted to determine the responses of a prototype smoke detector and a commercially available photoelectric smoke detector to smoke particles generated from various combustion sources. The prototype smoke detector combines optical scattering measurements with ionization chamber measurements in order to reduce/eliminate nuisance alarms due to the presence of airborne dusts or diesel exhaust particles. The commercially available smoke detector is designed for use in harsh environments where airborne dust represents a major problem due to both nuisance alarms and detector contamination. In the experiments, the responses of the two detectors were measured when exposed to smoke particles from the exhaust of a diesel engine and from a variety of fire sources, including wood, coal, styrene butadiene rubber, and No. 2 diesel fuel. For the solid fuels, data were obtained for both smoldering and flaming combustions. This report describes the experiments, their results, and the use of these results as they apply to early-warning fire sensors capable of the rapid and reliable detection of fires in atmospheres that may or may not be contaminated by either airborne dust or the products produced from diesel engines.

Jan 1, 2008

By A. B. Hooker, R. A. Kearns

Material used for flame safety lamp gauzes should possess the following qualities: (1) mechanical strength, (2) resistance to corrosion under service con- ditions, (3) a relatively high thermal conductivity, (4) a melting point above the ignition temperature of mine gas. Heretofore, three metals have been used for flame lamp gauzes, namely: steel, brass and copper. While each of these has the requisite qualities to some extent, none of them is an ideal gauze material. Copper gauzes lack mechanical strength, especiall, after they have been heated; brass and copper both have comparatively low melting points so that before the gas ignition is reached the gauze metal is attacked and oxidized under the action of the heat. Steel corrodes readily in damp atmos- pheres and if the lamp stands unused under these conditions for some time, the gauzes become unfit for service. Tests of these three materials have shown that steel offers the highest degree of safety. Manel metal, the natural alloy of nickel and copper, is practically noncor- rodible. Its relting point is approximately the same as that of steel. From time to time it has been suggested that this alloy might be a better gauze material than steel, since gauzes made of Monel metal should have all of the good qualities that steel gauzes possess and, in addition, would not corrode appreciably in ordinary mine atmospheres. One advocate of this use for Monel metal, the International Nickel Co., through their development engineer, Mr. Robert J. McKay, cooperated with the Interior Department, Bureau of ines, to the extent of supplying twelve sets of 30 mesh, Monel-metal gauzes for tests. Those gauzes were made up by the same lamp manufactur- er ho rade the steel gauzes used in the previous investigation. Being made by the same processes as the steel gauzes, these Manel-metal gauzes were needlessly given the same anti-rust coating that is always applied to steel gauzes to prevent any corrosion before the gauzes are used. In previous tests the Bureau of Mines had collected data as to the behavior of steel gauzes. In determining the value of Monel metal as a gauze material, it was planned to obtain similar data with Monel-metal gauzes, and thus make a direct comparison with the steel gauzes. In addition, steel and Monel-metal gauzes

Apr 1, 1923

By Steven J. Page

Overexposure to airborne respirable crystalline silica dust can cause disabling or fatal respiratory disease, and mine worker exposure to silica dust continues to be an ongoing occupational health concern. Exposures of surface coal mine rock drillers to respirable crystalline silica are of particular concern. On surface coal mine drills, bailing air flushes the cuttings out of the drill hole. Conveyor belting material is typically used to fabricate a shroud around the drill deck in an effort to contain the drill dust so that it can be captured by a collector. Dust leakage from the drill shroud is usually the worst dust source problem on most drills. The focus of this work is drill shroud dust leakage and the relationships of various drill parameters on this leakage. Experimental data were obtained and used in combination with dimensional analysis to establish these relationships. In general, it is found that airborne respirable dust (ARD) concentrations vary in a direct relationship with shroud leakage area and in an inverse relationship with drill deck cross sectional area and shroud height. This work expands the testing and dimensional analysis previously reported for collector/bailing air flow ratios ranging from 2:1 to 4:1 to include ratios approaching 1:1. A semi empirical mathematical model has been developed and expanded to describe ARD generation on surface coal mine drills. Geometric parameters included are drill deck height and cross sectional area, shroud leakage associated with the deck shroud, and the operational parameters of bailing airflow and dust collector airflow. The relationships can be described by logarithmic functions and yield predictive ARD values, which fall in the range measured on operating drills for collector/bailing air flow ratios greater than 2. However, at values of collector/bailing air flow ratios of approximately 1.1, the amount of ARD shows minimal response, if any, to drill deck shroud improvements that do not result in near perfect seals. This is a condition that can occur in actual operation and is a substantially different result than previously expected and reported. Application of these results should provide mine operators with sufficient information to determine (1) the relative magnitude of their dust emissions, (2) where they should focus their efforts to reduce ARD emissions and (3) the improvement they could reasonably expect to achieve. Given that exposures of surface coal mine rock drillers to respirable crystalline silica are of particular concern, substantial reductions of airborne silica dust during drilling may be estimated and achieved through use of the analysis presented. Keywords: drill; dust; model; dimensional analysis

Jan 1, 2008

By BUREAU OF MINES

The Bureau of Mines in its investigations of respiratory apparatus for use in mines and allied industries, tests equipment that is voluntarily submitted by manufacturers in accordance with published schedules of tests. These tests are designed to insure that the equipment has the minimum require- ments for safety in use. Approval certificates are issued for apparatus that meets the bureau's specifications, and the memfacturer is permitted to mark his equipment with a seal showing that it has been approved as "Permissible." A complete list of permissible self-contained oxygen breathing apparatus, gas masks, and hose masks tested before July 1, 1930, was published in Bureau of Mines Information Circular 6362.1 The present list includes all equipment tested and approved up to and including April 1, 1931.

Sep 1, 1931

By Robert W. Freedman

This report describes sampling and analytical procedures used for measurement of sulfates in diesel tailpipes and in the diluted exhaust within dilution tunnels. A variety of methods exist for sulfate analysis for such systems, including ion exchange. Two chemical methods used by the Bureau of Mines are described in detail. These are based upon spectrophotometric measurement of chloranilic acid using barium chloranilate. The procedures are rapid and relatively inexpensive. In general, ion exchange is preferred by many analysts for sulfate analysis. However, it is more complex and expensive than chloranilic acid procedures, which are adequate for exhaust analysis.

Jan 1, 1982

By Fred N. Kissell

Tracer gas decay curves were experimentally obtained in a full-scale model coal mine working face area. The concentration of tracer gas was found to decay in exponential fashion but with a change in slope. This change in slope is attributed to eddy zones in the face area. A simple theory was developed that allows one to calculate the approximate amount of gas in the eddy zones and thus estimate the size of the eddy zones.

Jan 1, 1974

By Michael A. Trevits

The National Institute for Occupational Safety and Health (NIOSH) in partnership with Strata Products tested the sealing capability of Ventstop®? as part of an ongoing mine fire control and suppression research program. Ventstop®? is a multi-purpose, inflatable device that is produced by Minvent Solutions and is available world wide for use in the metal and nonmetal mining industry. Ventstop®? is also used in the Australian coal industry as a temporary ventilation control device. The device can be quickly deployed, is reusable and can be placed in horizontal and vertical mine voids to control dust, fumes and smoke. Deployment, multi-day inflation and air leakage tests were conducted at the NIOSH Lake Lynn Laboratory to determine the capability and limitations of Ventstop®? in a simulated coal mine setting. During the tests, Ventstop®? was also subjected to low level forces of a nearby methane gas ignition. It is thought that Ventstop®? could be used by the US coal mining industry to temporarily close an underground mine area in response to a fire or spontaneous combustion heating event, to temporarily redirect mine ventilation during longwall equipment moves or during stopping construction. This paper describes this inflatable temporary mine sealing technology and presents the results of the NIOSH tests. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

Jan 1, 2009

By P. Kovalchik, S. Peng, G. Cole, R. Matetic

Previous studies conducted by the National Institute for Occupational Safety and Health (NIOSH) have shown that approximately 90 percent of coal miners and 49 percent of metal/nonmetal miners had a hearing impairment by age 50 (Franks, 1997). Mine workers are exposed to additional noise levels underground due to the reflection of machine-generated noise that would otherwise dissipate in an aboveground setting. Determining the sound-absorption coefficients is essential in modeling the sound field in an underground mining environment. Sound absorption is a measure of the amount of acoustic energy that strikes a surface and is absorbed rather than being reflected. The acoustic environment that mining machines operate in is a critical factor affecting the sound pressure level exposure for mining machine operators. Impedance tube testing is an inappropriate method for determining underground absorption coefficients due to the brittle composition of materials such as coal and slate. Classic absorption coefficient estimation using T60 measurements will not work well in an underground environment because the theory assumes a finite room, a diffuse field and a relatively uniform absorption. None of these assumptions are true in an open-ended mine entry. This paper presents a method using a ray-tracing technique to determine absorption coefficients for underground mines. Absorption coefficients are determined and presented for octave bands from 63 Hz to 8 kHz. The absorption coefficients are essential for determining and predicting potential overexposure to machine operators in different mine environments.1

By Martin Harper

This paper concludes a five year program on research into the use of a portable X ray fluorescence (XRF) analyzer for analyzing lead in air sampling filters from different industrial environments, including mining, manufacturing and recycling. The results from four of these environments have already been reported. The results from two additional metal processes are presented here. At both of these sites, lead was a minor component of the total airborne metals and interferences from other elements were minimal. Nevertheless, only results from the three sites where lead was the most abundant metal were used in the overall calculation of method accuracy. The XRF analyzer was used to interrogate the filters, which were then subjected to acid digestion and analysis by inductively coupled plasma optical emission spectroscopy (ICP OES). The filter samples were collected using different filter holders or "samplers" where the size (diameter), depth and homogeneity of aerosol deposit varied from sampler to sampler. The aerosol collection efficiencies of the samplers were expected to differ, especially for larger particles. The distribution of particles once having entered the sampler was also expected to differ between samplers. Samplers were paired to allow the between sampler variability to be addressed, and, in some cases, internal sampler wall deposits were evaluated and compared to the filter catch. It was found, rather surprisingly, that analysis of the filter deposits (by ICP OES) of all the samplers gave equivalent results. It was also found that deposits on some of the sampler walls, which in some protocols are considered part of the sample, could be significant in comparison to the filter deposit. If it is concluded that wall deposits should be analyzed, then XRF analysis of the filter can only give a minimum estimate of the concentration. Techniques for the statistical analysis of field data were also developed as part of this program and have been reported elsewhere. The results, based on data from the three workplaces where lead was the major element present in the samples, are summarized here. A limit of detection and a limit of quantitation are provided. Analysis of some samples using a second analyzer with a different X ray source technology indicated reasonable agreement for some metals (but this was not evaluated for lead). Provided it is only necessary to analyze the filters, most personal samplers will provide acceptable results when used with portable XRF analysis for lead around applicable limit values.

Jan 1, 2007