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By Charles D. Litton

A new prototype ionization-attachment fire detector was developed by the Bureau of Mines for detecting combustion-generated submicrometer particulates. It is much more sensitive than the conventional ionization smoke detector, and it has the following added features: 1. A primary charging current of unipolar air ions is generated by a gold-coated, radioactive center electrode of a cylindrical diode. 2. Submicrometer particulates are flowed axially through the unipolar cloud where they acquire charge. The charged particles impinge upon a third electrode, located downstream, resulting in a current which is directly proportional to the particulate concentration. 3. Additional electrodes analyze the particulates in terms of their mobility and thus determine their size distribution. 4. A filter and cyclone assembly protect the ionization chamber against ambient dust. An analysis of conventional ionization smoke detector performance is also presented in terms of source strength, chamber geometry, and applied potential.

Jan 1, 1977

By Nancy Estrada, Jane Nowell, Cathy Jennings, Debra Yniguez, Carol Lavery, Kristin Harrer

Pilots of the MH-60S helicopter are exposed to continuous whole body vibration (WBV). Pilot fatigue is a growing operational concern due to the increased frequency of extended durations of missions (6-8+hours) in support of Operations Iraqi Freedom and Enduring Freedom. Endurance aspects of the currently used rotary wing seating systems were not optimized for the longer missions and wide range of pilot anthropometric measurements, which is now typical of naval aviation. The current seating systems were designed primarily to meet crashworthiness requirements, not for the wide range of pilot anthropometry or to mitigate WBV. Albeit, an issue, pilot fatigue and reduced mission effectiveness are also critical concerns. Current Hazard Reports indicated that pain in pilots’ legs and backs begin two to four hours into the flight and increase with time. Mission readiness also decreases with an increase in flight duration due to the constant distraction of pilots shifting in their seats while trying to get comfortable. Froom, et al [2] reported a dose-response relationship between the length of military helicopter flights and back discomfort. He also concluded that this pain is typically dull, over the lower back, and its prevalence and intensity are dependent on the total flight hours of exposure. Methods This study evaluated WBV produced in the pilot seating systems onboard the MH-60S. The purpose of the study was to test and compare the effectiveness of two different seat cushions, the current seat cushion versus an anti-vibration seat cushion. Both seat cushions were measured for acceleration levels averaged over five-minute intervals using a triaxial seat pad accelerometer. The recordings were completed for a 3-hour straight and level flight. A frequency analysis from 0-80 hertz (Hz) was conducted on all acceleration measurements to determine the dominant axis and frequency of the pilots’ vibration exposure. The results were then compared to the applicable Threshold Limit Values (TLVs) established by the American Conference of Governmental Industrial Hygienists (ACGIH) [1] and the International Organization for Standardization (ISO) 2631.1 [3] to determine the MH-60S pilots’ permissible exposure time for both seat cushions. Results The results of the study showed that for both seat cushions the vibration levels of the z-axis at 16 Hz had the shortest allowable exposure duration, according to the ACGIH TLVs. In the z-axis at 16 Hz, the MH-60S’s current seat cushion’s acceleration levels indicated an exposure time limit of approximately 6 hours, while the anti-vibration seat cushion’s acceleration levels pierced the 8-hour exposure time limit curve. This is shown in the graph below.

Jan 6, 2006

By Kathleen M. Kowalski-Trako?er

National Institute for Occupational Safety and Health re­searchers conducted a study to investigate the human response issues related to wearing a self-contained self-rescuer (SCSR). The goal was to develop training to educate miners on what they could expect from their units during an escape. Subjects included miners who had experience wearing SCSRs, manu­facturers, and researchers. Results identified nine key areas of concern: (1) starting the unit, (2) unit heat, (3) induction of coughing, (4) unit taste, (5) difficulty in breathing while wearing the unit, (6) quality of the air supplied, (7) nose clips, (8) goggles, and (9) the behavior of the breathing bag. In addition, researchers reviewed the literature on human response under duress. This article describes the expectations training program, which comprises the findings of the SCSR study and what is known about the normal human response in an emergency. The authors present background on SCSRs and the SCSR switchover procedure mandated in the recent federal Mine Improvement and New Emergency Response Act of 2006, which provided the impetus for the expectations training. Keywords disaster, escape, mining, self-contained self-rescuer, training

Jan 1, 2008

By Staff

A major emphasis of the U.S. Bureau of Mines is to perform research on the prevention of fatal accidents at mining operations. The leading cause of fatalities in the underground coal mining industry is groundfalls. This proceedings volume presents several new developments that are helping to prevent fatalities and reduce injuries by groundfalls. The papers focus on the problem from two different perspectives. About half of the papers present information and techniques that can be used to train and motivate miners to protect themselves from groundfalls. The other papers explain how to identify and respond to various geologic conditions that affect the stability of the mine roof. Of the 95 groundfall fatalities that occurred during 1986-90, 75% took place in Kentucky, West Virginia, and Virginia. The rate of groundfall fatalities was much higher at small mines. During 1986-90, the rate of groundfall fatalities at mines employing fewer than 20 people was 4.3 times higher than the rate for larger mines. Because so many groundfall fatalities are occurring at relatively small mines in the southern Appalachian coalfields, many of the papers focus specifically on the needs of this category of mine operations.

Jan 1, 1992

By D. B. Taliaferro

[Recovery of core specimens from subsurface formations and their subsequent analysis are important aids in efficient development and operation of oil and gas fields. Core specimens first were obtained mainly for the geologic information they revealed; now they are analyzed to determine many of the physical characteristics and conditions of tae subsurface formations as well. Cores recovered from the producing formations may be analyzed for porosity, permeability, oil content, "connate" water content, and other physical and chemical properties of the formation, all to the end of furnishing enough data for making reliable estimates of the quantity and availability of oil and gas within a reservoir and in devising, efficient means for their withdrawal.]

Jan 1, 1939

By J. L. Konchesky

The technical feasibility of gasifying powdered, noncoking, low-rank coal with steam in an externally heated tube has been demonstrated. The tube, 112 ft. of alloy-steel tubing shaped into a helix, served as an electrical conductor of electricity used for heating. The effects of the following variables were studied: Residence time of coal in reactor, average reaction temperature, steam concentration, and rank or geologic age of coal. Reaction pressure was maintained in the range 19-26 p.s.i.a. High carbon conversions and large yields of synthesis gas were obtained with low-rank coal. In one test, for example, about 88 pct. of the carbon in a subbituminous C coal was gasified at 1,910* F. with a residence time of 1 sec. The gas contained 58 pct. H2, 19 COD 15 CO, and 3 CH4; the yield was 30 cu. ft. (at 32' F. and 14.7 p.s.i.) of synthesis gas (CO + H2) per pound of dry coal.

Jan 1, 1960

By Constantine C. Popoff

The Hermada antimony deposit is in the Sewtooth Range in southwestern Idaho, about 77 miles by road northeast of Boise. Stibnite mineralization occurs over an area one mile wide from west to east and two miles long. It is locally referred to as the Swanholm district. In 1947 high- grade stibnite ore was discovered on the East Fork of Swanholm Creek. Since then, ore in commercial quantity has been produced by the Hermada Mining Co. The total output for 1947-50 was about 5,000 tons of ore, containing 640 short tons of antimony metal.

Jan 1, 1953

All of the coal resource in North Dakota is lignite. The lignite fields of North Dakota cover approximately 40 percent of the total area of the state, with reserves estimated to be 9.8 billion tons, two percent of the U.S. base. The first commercial coal mine in North Dakota opened in Morton County in 1873. As the railroads crossed the plains, the demand for coal increased. Coal for fuel was supplied by the state's underground mines. By 1884, North Dakota's lignite production had reached 35,000 tons. North Dakota was among the fist states to shift from underground to large-scale commercial surface coal mining. By 1927,40 percent of the total production was by surface mining, compared to 2 percent for the nation as a whole. By 1959,86 percent of the total production was by surface mining, while the national average was 22 percent. Since 1966, surface mining has been the exclusive coal production method in North Dakota. North Dakota's regulatory program received conditional approval December 15, 1980. Following approval of amendments to the program, it received full approval February 18, 1986. The Abandoned Mine Lands Program was approved December 23,1981.

Jan 1, 1992

By J. L. Holman

In conjunction with its research program on separation, recovery, and recycling of metal, mineral, and energy-based materials in urban refuse, the U.S. Bureau of Mines is developing means to reuse and recycle plastics discarded in raw municipal waste. Experimental work on plastic waste from a community collection has produced some guidelines for systematic methods of processing, including air classification, cleaning, separation, and use or disposal. Sink-float methods are a practical means of separation into types. Methods for final disposition of the plastic waste include refabrication, thermal decomposition, and incineration.

Jan 1, 1972

By S. Gallagher, C. A. Hamrick, A. G. Mayton, R Sonier, R. L. Unger

Introduction Industrial safety professionals recognize that adequate illumination is essential to a safe and productive work environment. The need for effective, lighting in underground coal mines is even greater.1 Designing appropriate lighting systems for these mines is no easy [ ] task because of the unique environment and work procedures encountered in underground coal-mining operations. Miners must depend totally on artificial lighting systems to see. Moreover, the working face is a low-reflectivity and low-contrast environment and is continually advancing or retreating.2 Laboratory mock-ups have been a major part of the process lighting equipment manufacturers must under- go to design an underground machine-mounted lighting system. The mock-ups often have taken considerable time. Furthermore, modifications to a lighting system (using different luminaires with an existing configuration or changing a luminaire's location, orientation, etc.) could require more time with additional mock-ups and laboratory measurements. Understanding the need to improve this situation, the US Bureau of Mines has developed an alternate method for facilitating lighting system mock-ups. A PC-Program (CAP),* with the latest software technology enables users to design, alter, and evaluate under- ground machine-mounted illumination systems. Lux levels and distance are measured as the luminaire is moved incrementally through angular traverses about horizontal and vertical axes. The measurements and angles subsequently are entered into the model. From this input data, three-dimensional isolux or isofootcandle profiles are constructed for luminaires that can be placed at various locations and orientations on a mining machine. As an example, Figure 1 shows a computer display of 21.5 Ix or 2.00 fc profiles for luminaires mounted on a simulated mine-shuttle car. Using this information, the model allows the user to determine the lux level at different locations in space about the shuttle car. How the model calculates illumination During initial development of the CAP model, the isolux profile of the luminaire was determined using the inverse square law (ISL) .3 The method of gathering data comprised recording a single measurement of distance at 21.5 ± 1.21x (2.00 ±11 fc) for angular traverses following 0.09 rad (5 degree) increments. This data was then used to find the illumination in space for any other distance at a given azimuth and elevation using the ISL. Limitations, however, exist with this method.4 The main one is that the ISL assumes a luminaire is a single point source of light, so long as the distance is greater than five times the 1al;gest dimension of the luminous area of the luminaire.5 Also, by using a single measurement to calculate the illumination for a given luminaire in the CAP model a large error could result from an inaccurate measurement.

By Naoki Hosoya, Setsuo Maeda

This paper addresses establishment of an experimental system for measuring biodynamic response (BR) of hand-arm system at the NIIH in Japan. BR measurement system at the NIIH is nearly equivalent to NIOSH installed system. The feasibility of the system is examined through the apparent mass (AM) measurement of the empty handle and a set of calibration masses. Apparatus The grip force was measured by using the handle shown in Fig. 1. The handle has two force sensors (KISTLER, 9212) and one accelerometer (PCB, 356A12). A low-pass filter with 5 Hz cut-off frequency was used to the grip force from measured force signal. Figure 2 shows BR measurement system in this study. The push or pull force at the handle was measured by using the force plate (KISTLER, 9286AA). The grip force and the push / pull force were displayed on a monitor. The shaker (IMV, VE-100S) is used to vibrate the hand-arm system along the forearm axis (Zh direction) (ISO 10068, 1998; ISO 5349-1, 2001). In most situations force actions for operating tools are expressed by grip, push, pull and combined these actions. These actions can be simulated in the test system. AM was obtained by performing H1 estimator in the PULSETM system (B&K, 3109) and it is denoted at the one-third octave band center frequencies. [ ] Methods In order to investigate the reliability of the system, AM measurement of the handle was performed. It is assumed that the handle is rigid in the upper limit of adoptive frequency range in this study. This assumption is validated in AM measurement of the empty handle. A pseudo-random vibration in the frequency range of 10 to 1,250 Hz was used and its amplitude is 1.0 (m/s2)2/Hz with a flat power spectral density (PSD) in the experiment. Measured AM includes the mass effect of the measuring cap in a subject experiment. Compensated apparent mass AMc(?) is obtained by Eq. (1) 1-2.

Jan 6, 2006

By Sidney Katell

This report covers the period January 1963 through December 1963; it is a continuation of the series that began with the publication of Information Circular 7516 in October 1949. Also, it is the fifth in a series of reports prepared under a cooperative agreement between the Bureau of Mines and the American Association of Cost Engineers. The agreement provides for the publication of an annual cost bibliography with the work load involved in the preparation shared equally. The abstracted articles, concerned with all facets of cost engineering in the field of chemical and petroleum plants and related subjects, are from the following sources:

Jan 1, 1964

By E. A. Rowe, G. H. Keith, B. D. Jones

An evaluation of electrowon tungsten powder was made by comparing its characteristics with conventional hydrogen - reduced tungsten powder . Electrowon tungsten powder was investigated with respect to particle size and shape , apparent density , flow rate , compressibility , green strength , and sintering characteristics . In addition , its chemical purity , absolute density , and purification by melting were determined . Significant findings were higher flow rates and better compressibility than hydrogen - reduced tungsten powder . However , the large particle size peculiar to the electrowinning process effectively prevented conventional sintering to a high- density material . The possibility of producing high - density material , using a new technique of hot swaging sheathed sintered - tungsten compacts , was demonstrated by the achievement of densities of 92 percent of theoretical .

Jan 1, 1965

By Townsend. James W.

"INTRODUCTION As a byproduct of its mineral investigation program, the Bureau of Mines has developed a number of operating devices and techniques worthy of note. This paper, prepared under the direct supervision of Paul T. Allsman, chief, Salt Lake City Division, Branch, and under the general supervision of Lowell B. Moon, chief, Mining Branch, reports upon one such device. A simple device has been developed for measuring angles of deviation from the horizontal as recorded on a glass tube by acid etching. The device has facilities, also, for measuring the angle between the long axis of the ellipse and the north-south reference points established by a Maas compass or from an established axial lamina, on the tube, which was ori¬ented to a specific direction in the hole by rod alinement.The device was found accurate within half a degree on repeated orientations of the same tube. However, the degree of accuracy is dependent on the accuracy of personal manipulation in orienting the tube to the correct plane."

May 1, 1947

By Bertrand L. Johnson

Langbeinite, a comparatively rare mineral that has been reported from only five countries in the entire world, has recently attained considerable economic importance in the United States and Poland. Since September 1940, several hundred thousand tons have been produced in one of the Carlsbad (N. Mex.), potash mines for chemical and fertilizer use. As it is a newcomer in this field, and as it is the source of fertilizers possessing special advantages, notably for soils deficient in magnesium or requiring sulfate fertilizers, a discussion of its properties, occurrences, uses, mining, and treatment is appropriate at this

Jan 1, 1944

By N. Kumar Kittusamy

Operators of construction equipment perform various duties at work that expose them to a variety of risk factors that may lead to health problems. A few of the health hazards among operators of construction equipment are: (a) whole-body vibration, (b) awkward postural requirements (including static sitting), (c) dust, (d) noise, (e) temperature extremes, and (f) shift work. It has been suggested that operating engineers (OEs) are exposed to two important risk factors for the development of musculoskeletal disorders: whole-body vibration and non-neutral body postures. Method: This review evaluates selected papers that have studied exposure to whole-body vibration and awkward posture among operators of mobile equipment. There have been only few studies that have specifically examined exposure of these risk factors among operators of construction equipment. Thus other studies from related industry and equipment were reviewed as applicable. Conclusion: In order to better understand whole-body vibration and postural stress among OEs, it is recommended that future studies are needed in evaluating these risk factors among OEs.

Jan 1, 2004

By Robert C. Gabler

Three filter cloth fabrics commonly used in drains for coal waste embankments were tested by the Bureau of Mines for clogging behavior and deterioration under simulated field conditions. The objective was to provide guidelines for the mining industry for the proper selection and use of filter cloths to assure safer embankments at mine waste disposal sites. The filter cloths were tested with three coal waste samples in stand-pipes used to simulate coal mine waste disposal environments. Two of the cloths showed a tendency to become clogged with fines from the wastes. One waste caused clogging by precipitating an iron-silicon compound on the test cloths. No apparent cloth deterioration resulted from exposures to the simulated coal waste environments. (The exposures ranged from 2 to 12 months.) In other tests, exposures to waters in the pH range of 2 to 12 and to reagents used in coal-preparation plants resulted in insignificant or no deterioration, as measured by tensile strength. However, long exposures to sunlight (ranging from 4.6 to 6 months) caused major deterioration in two of the cloths (86-and 98-pct losses in tensile strength) and slight deterioration in the third cloth (9-pct loss in strength).

Jan 1, 1984

By John T. Dieckmann

This report documents the work performed and the results obtained in a 2-year development of a Mobile Inert Gas Generator for use in the Bureau of Mines Remote Sealing System for fighting underground coal mine fires. The performance requirements of an inert gas generating system for the Remote Sealing System were clearly established. A thorough review of seven possible system designs meeting these requirements was conducted. An air cooled, distillate oil fired combustion type inert gas generator was selected for further detailed design, hardware fabrication, and performance testing. The Inert Gas Generator constructed under this program has been thoroughly performance tested and has been operated in the field for approximately 200 hours. The system has met or exceeded all important performance requirements. The system was used in the fire fighting efforts at the Bethlehem Mines Corporation Cambria Division Mine 33 fire and contributed to the successful containment of the fire. The system was also employed in the demonstration of entire Remote Mine Sealing System at the Jenney Mine in the fall of 1978. The system is currently avail-able for fighting any future underground coal mine fires.

Jan 1, 1979

By Ren G. Dong, Dan E. Welcome

Instrumented handles or dynamometers are widely used to measure hand forces and/or the biodynamic response of hand-arm system. To study hand-transmitted vibration exposure, six generations of instrument handles were constructed or initially developed by researchers in ECTB/HELD/NIOSH. This presentation provided a summary of these handles. Their basic characteristics, limitations, and usefulness are described, which may help their appropriate applications and further improvements. Six Designs of Instrumented Handles Handle 1: The conceptual design is recommended in ISO 10819 (1996)1 for glove test. The grip force is measured by detecting bending strains on a measuring beam in the handle. A special handle fixture was designed to connect the handle to a shaker. Except the screws, the handle and fixture were made from aluminum. Handle 2: The design is based on the principle of shear strain measurement.2-3 Both grip and push forces can be measured simultaneously using this handle. This handle was directly designed for a simulated vibrating tool. Handle 3: This design is basically composed of a handle base, a measuring cap, and two charge-based sensors (Kistler 9212) sandwiched between the base and cap. The handle was also made from aluminum. The fixture for Handle 1 was also used with this handle. This generation of handle has three different handle diameters (30, 40, and 50mm).4 Handle 4: This design is an improvement from Handle 3. The handle fixture was totally redesigned and it was much stiffer than the previous one. The aluminum measuring cap was replaced with a magnesium cap. Handle 5: The basic structure of this handle is the same as that for Handle 3. However, the piezoelectric sensors were replaced with two strain gage based sensors (Interface SML-50). Handle 6: This handle includes two measuring caps, four piezoelectric sensors, and a handle centre base. The handle fixture was the same as that with Handle 4. Methods for Handle Examinations The static and dynamic characterizations were performed using the methods reported by Dong et al.5-6 Results and Discussion Handle 1: The static force measurement depended on the hand grip location on the handle. Its natural frequency was less than 200 Hz.5,6 Because the transmissibility of gloves may not vary significantly with the applied grip force, this handle may be acceptable for glove test. However, the force measurements with this handle may not be reliable. Handle 2: The static force measured with this handle was insensitive to the hand acting location. However, when the handle was vibrating, the force signals could be totally distorted. For this reason, it was not used for vibration studies.

Jan 6, 2006

By A. Salmoni, E. K. Gillin, T. Eger, A. Cann, P. Vi, M. Hunt

Kittusamy (Kittusamy & Buchholz, 2004) state that there have been few studies conducted to assess exposure to whole-body vibration (WBV) in the construction industry. They suggest that there is very little reliable data from the construction industry that characterizes exposure levels to various hazards including WBV or the health outcomes from such exposure and that there is a need for more exposure data. In a recent exploratory study of heavy construction equipment Cann (Cann, Salmoni, Vi, & Eger, 2003) looked at vibration levels for 14 different types of construction equipment. Eight of the 14 pieces of equipment tested exposed operators to levels of WBV that exceeded the recommended limits for an 8-hour period when comparing the measured VDV to the ISO 2631-1 standards. The purpose of the present research was not only to test a larger number of scrapers but also to investigate scraper operator exposure to whole body vibration (WBV) separately for each task. Methods 33 scrapers were evaluated for WBV in a variety of residential and road construction projects. Testing equipment consisted of triaxial accelerometers that allowed vibration data collection in all three orthogonal axes, with the x-axis positioned to measure vibration in the anterior-posterior direction, the y-axis in the medial-lateral direction, and the z-axis in the vertical direction. Root mean square accelerations (aRMS), vibration dose value (VDV), crest factor, and maximum transient vibration values (MTVV) were derived from this software and exported to an Excel™ spreadsheet for later data analysis. Test sessions for each piece of equipment lasted for approximately 20 minutes until at least three work cycles had been completed. Tasks included: idling while waiting for a bulldozer to push the scraper through the scraping phase, scraping, traveling loaded with dirt, dumping and traveling empty. Results Task breakdown by time reveals 25% of the work cycle was spent traveling fully loaded with dirt, 19% dumping, 21% traveling unloaded, 17% idling and 18% scraping. Calculation of aRMS vector sums gave values of 2.55 m/s2 during loaded transport, 2.46 m/s2 during dumping, 2.31 m/s2 during unloaded travel, 0.55 m/s2 during idling and 1.46 m/s2 during scraping (see Table 1). The highest acceleration values recorded were found in the z-axis during fully loaded transport reaching an average aRMS over three work cycles of 2.55 m/s2.

Jan 6, 2006