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By R. L. Derick

On a regular basis, mine personnel should obtain air samples directly from active underground areas as well as remotely from sealed locations. These samples provide mine officials with data relative to the makeup of the various atmospheres. Should conditions underground change, these results can provide a baseline that can assist officials in determining the extent of change. Relating the concentrations of individual gases to time, applying gases to equations, and examining their change over time are tools that have been successfully used to determine if a heating event exists and, if so, the extent of the emergency. These atmospheric status equations have either been developed for the mining industry or adapted from other industries. They serve as tools to assist personnel in determining the condition of underground mine atmospheres. As long as the problem area continues to be ventilated, certain gases, gas ratios, and equations can be used to determine if a fire exists, what type of material could be burning, and what quantity of coal is burning. Once the mine or the involved section has been temporarily sealed, gases, ratios, and gas-derived equations can assist personnel in determining how conditions within the sealed volume are changing over time. To alleviate potential explosions when fresh air is once again introduced into the sealed volume, equations and a diagram have been developed to predict the likelihood of an explosive atmosphere. Similarly, prior to commencing recovery of a mine or section, equations exist that can assist in determining if the fire will rekindle when air is reintroduced. This paper serves as an overview to remind and/or instruct readers about gas-sampling methodologies and gas analyses to assist in determining the status of underground atmospheres.

By Robert F. Randolph, Christa L. Themann, Efrem R. Reeves, Thais C. Morata, Babette L. Verbsky, David C. Byrne

Objective: Workers with hearing loss face special problems, especially when working in noise. How­ever, conventional hearing conservation practices do not distinguish between workers with normal hearing versus impaired hearing. This study col­lected information from workers with self-reported noise exposure and hearing loss, supervisors of such workers, and hearing conservation program managers through focus groups and in-depth inter­views to evaluate their perspectives on the impact of hearing loss on safety and job performance, the use of hearing protection, and information needed to appropriately manage hearing-impaired workers who work in noisy environments. Results: Concerns about working in noise with a hearing loss could be grouped into the following 10 categories: impact on job performance, impact on job safety, impaired ability to hear warning signals, impaired ability to monitor equipment, interfer­ence with communication, stress and/or fatigue, impaired communication caused by hearing protec­tor use, reduced ability to monitor the environment as the result of hearing protector use, concerns about future quality of life, and concerns about future employability. Mostly, there was an agree­ment between the perceptions of workers, supervi­sors, and hearing conservation program managers regarding difficulties associated with hearing loss and consequent needs. These findings suggest that noise-exposed workers with hearing loss face many of the same problems reported in the literature by noise-exposed workers with normal hearing, with additional concerns primarily about job safety as the result of a reduced ability to hear environmental sounds, warning signals, and so forth. Conclusions: The study outlines potential chal­lenges regarding job safety and hearing conserva­tion practices for noise-exposed, hearing-impaired workers. Awareness of these issues is a necessary first step toward providing appropriate protective measures for noise-exposed, hearing-impaired workers. Of the 19 million adults in the United States with some degree of hearing trouble, nearly half are currently employed in the workforce (NCHS, 1994). More than 30 million US workers are exposed to hazardous noise levels, and noise-induced hearing loss is the most common occupational disease in the United States (NIOSH, 1996). Many workers incur their hearing losses during the first 5 to 10 yrs of employment (Rosler, 1994; Ward et al., 2000) and subsequently work the rest of their careers in an environment where noise and hearing loss interact to impair their ability to hear communication and other important signals. Workers with hearing loss who are exposed to hazardous noise levels present a dilemma to hearing loss preventionists. On the one hand, it is of great importance to ensure that their residual hearing is protected from the damaging effects of the noise to which they are exposed. On the other hand, how­ever, traditional hearing protectors serve to further “deafen” such workers, making communication more difficult and impairing the detection of environmen­tal sounds and warning signals. These workers have special needs that must be addressed. However, conventional hearing conservation practices do not distinguish between workers with normal versus impaired hearing; and, to date, no governmental or professional organization has developed specific guidelines or policies concerning the accommodation of noise-exposed, hearing-impaired workers. Some research regarding noise-exposed, hearing-impaired workers has been completed. These studies have primarily focused on three areas: (a) speech intelligibility in noise versus quiet, with and without various types of hearing protection devices (Abel et al., 1982; Abel et al., 1993; Abel & Spencer, 1997; Rink, 1979; Suter, 1989); (b) signal detection and localization under similar conditions (Abel et al., 1993; Abel et al., 1985; Abel & Hay, 1996); and (c) the use of hearing aids as hearing protectors (Berger, 1986; Dolan & Maurer, 1996; Hétu et al., 1992; Hétu et al., 1993). Research in these three areas has provided an initial framework for development of a management para­digm for these workers. However, each of these studies addressed a very specific research question, examining

By E. H. Denny

The subject of haulage and heisting hazards is one that merits the attention of everyone engaged in mining. The purpose of this circular is to the importance of such hazards as are shown by Bureau of Mines accident figures, to give some examples of recent accidents and briefly analyze the immediate contributing causes, and to discuss some general means found by metal- and coal-mining companies to minimize those hazards. Haulage and hoisting accidents collectively constitute the second most common cause of accidents in and about coal mines and the third most common cause in and about metal mines. In both these types of mines falls of ground cause more accidents than haulage, and in metal mines falls of persons in raises and similar openings also exceed haulage accidents in number.

Jan 1, 1942

By Michael J. Jorgensen, Anoop Polsani, Khurram S. Khan

Riveting operations in aircraft manufacturing involves the use of power tools for manually drilling holes for the rivets, power drills for the setting of the holes for the rivets, as well as rivet guns to drive and set the rivets. To close the rivet, the rivet is driven against a metallic bar commonly called a “bucking bar”. The bucking bars are typically held firmly to increase the quality of the riveting, as well as keep the bucking bar from “dancing” against the metal piece being riveted. Thus, employees in aircraft manufacturing involved in riveting are exposed to hand-arm vibration from several sources, and epidemiological evidence suggests that vibration-related musculoskeletal disorders are associated with long term exposure to riveting tasks in the aircraft manufacturing of aircraft.1,2 Recently, tungsten technology has been introduced into aircraft manufacturing for bucking bars, which are heavier than traditional steel bucking bars of the same size. Rivet guns with tungsten pistons instead of steel pistons have also recently been introduced with the objective of reducing vibration exposure to the riveter. The objective of this study was to assess vibration characteristics of steel and tungsten bucking bars and rivet guns to identify the combination that simultaneously reduced the combined exposure to both the “riveter” and “bucker”. Methods Vibration (10g tri-axial accelerometer, Biometrics S2-10G-MF Series 2) was measured from eight experienced employees using seven different rivet guns on size 6 rivets, with the same person bucking for all subjects. Vibration was also measured on two different bucking bars for these same eight subjects, with the same person driving the rivets using the various rivet guns. The rivet guns consisted of three E4 steel piston guns with different RPMs (Guns A-E4, B-E4, C-E4), an E4 vibration dampened rivet gun (Gun D-E4D), an E3 steel piston rivet gun (Gun E-E3) and an E3 and E4 tungsten piston rivet guns (Guns F-E3T and G-E4T). The bucking bars were made of 90% tungsten (1694g) and cold-rolled steel (843g), and were the same shape and size. A two-way repeated measures analysis of variance was performed on the vibration (mean frequency weighted resultant acceleration) on both the rivet gun side and the bucking bar side, and mean rankings were used to assess the vibration simultaneously for the rivet gun and bucking bars to investigate which combinations provided the lowest vibration exposure. Results Frequency weighted resultant acceleration was significantly lower on the E3 tungsten (F-E3T) rivet gun than the E4 steel piston (B-E4) and the E4 tungsten piston (G-E4T) rivet guns (Figure 1). When measuring vibration on the bucking bar, the E4 (A-E4) steel piston rivet gun resulted in lower vibration on the bucking bars than the E4 tungsten piston (G-E4T) and E4 vibration dampened (D-E4D) rivet guns (Figure 2). Additionally, use of tungsten bucking bars resulted in a 35% decrease in resultant frequency weighted acceleration than when using steel bucking bars.

Jan 6, 2006

By Jos. R. Guiteras

This paper describes the pumping operations at the Ajax, Cresson, and Vindicator dines in the Cripple Creek mining district of Colorado during the summer of 1936. At that time the three mines wore pumping 6,500 gallons of water per minute into the Roosevelt drainage tunnel. Cripple Creek is the most important gold district in the State; it has yielded gold valued at over $365,000,000. The mines engaged in pumping are among the largest producing properties in the district. ACKNOWLEDGMENTS The author wishes to acknowledge the friendly cooperation of mine officials at the properties visited. At the. Ajax mine information was courteously given by Clayton Kissel, mine superintendent, and his staff; R. Y. Roby contributed the drawings. For information on the Cresson mine, thanks are expressed to Al H. Bebee, mine superintendent, and his staff, especially to Guy Rorabaugh, master mechanic, and to engineer Carlton. At the Vindicator mine, J. S. Anderson; mine superintendent, and Robert Welch, master mechanic, assisted; the latter furnished most of the information about that mine. Acknowledgment is also made of the cooperation of M. H. Salsbury, engineer at the Portland mine, who supplied technical data on the Roosevelt drainage tunnel.

Jan 1, 1937

By H. Nelisse, S. K. Patra, A. Natani, S. Rakheja

The current laboratory methods for assessing the vibration attenuation performance of seats involve repetitive trials with a number of human occupants, and raise certain ethical concerns. Moreover, the measurements with human subjects yield considerable variability in the data. Alternatively, several anthropodynamic manikins have been developed for effective assessments of the coupled seat occupant system [1]. The effectiveness of a manikin in predicting the response of a coupled seat-occupant system lies in its ability to reproduce the biodynamic response of the seated human body in terms of force-motion relationship at the body-seat interface, such as apparent mass (APMS). A number of prototype manikins have thus been developed on the basis of biodynamic characteristics of vertical vibration-exposed seated occupants of different body masses in the vicinity of 5th, 50th and 95th percentile male population. This study concerns with the analysis of a passive prototype manikin to enhance its ability to reproduce the idealized APMS response characteristics of the vibration-exposed seated human subjects defined in ISO-5982[2] for mean body masses of 55, 75 and 98 kg. Methods The APMS responses of a prototype anthropodynamic passive manikin were thoroughly characterized in the laboratory under different excitations and body mass configurations. The manikin was designed with sufficient flexibility to configure mechanical-equivalent models corresponding to seated body masses of 55, 75 and 98 kg, by adding/removing specified masses and springs (Fig. 1). The manikin, configured for a specific body mass, was positioned on a rigid seat without a backrest, which was fixed to the force platform of a whole-body vertical vibration simulator. The simulator was programmed to synthesize random vertical vibration with flat acceleration power spectrum in the 0.4-20 Hz frequency range with two different magnitudes: 1 and 2 m/s2 overall rms acceleration. The total static and dynamic forces of the manikin to and the seat were measured using the force platform, while a single axis accelerometer was installed on the seat pan to measure acceleration due to vertical excitation. The measured data was appropriately corrected for the rigid seat inertia force, and the apparent mass [ ]

Jan 6, 2006

By Launa Mallett, Charles Vaught, Michael J. Brnich

Purpose: This training material focuses on the content of emergency warning messages. Research has shown that when an emergency occurs, people often do not get the information they need for the purpose of taking appropriate action. This safety talk presents a procedure, using mental cues that can be used by senders and receivers of emergency warnings. Intended Use: This material has been developed for use in short safety-training sessions such as start-of-shift safety or Atoolbox@ talks. The information can be presented in approximately fifteen minutes and is appropriate for workers at all experience levels. While the examples and illustrations are taken from the underground coal mining industry, the training can be tailored to any work setting by substituting appropriate examples. Materials Needed: The instructor will need to prepare the figures provided in a form that can be seen by the entire class. Suggested methods include the use of: (1) overhead transparencies, (2) laminated pages that can be held up for small groups, and/or (3) handouts with copies of the figures for each trainee. As a supplement, stickers featuring the communication triangle can be placed on hard hats, telephones or other communication devices to remind workers about the key to effective emergency communication. The Talk: The accompanying script is a guide for presenting this safety talk. Training is enhanced if these materials are covered but not simply read by the trainer. Examples given in this guide are from real experiences. To make training more interesting and effective, the instructor can substitute examples from his/her workplace. Additional Resources: The following references will provide further information about communications during emergencies. Auf Der Heide, E. (1989). Disaster Response: Principles of Preparation and Coordination. The C.V. Mosby Company, St. Louis. Mallett, Launa, Charles Vaught, and Michael J. Brnich Jr. (1993). A Sociotechnical Communication in an Underground Mine Fire: A Study of Warning Messages During an Emergency Evacuation@, Safety Science, 16, pp. 709-728. Nigg, J.M. (1987). A Communication and Behavior: Organizational and Individual Response to Warnings@ in Sociology of Disasters: Contributions of Sociology to Disaster Research, R.R. Dynes, B. De Marchi, and C. Pelanda (eds.), Franco Angeli, Milan, Italy, pp. 103-116.

Jan 10, 1999

By Donald Giroux

This report documents the design, fabrication, testing, and coal mine demonstration of a hopper-feeder-bolter during a four-phase program for the U.S. Bureau of Mines. The machine was designed to increase productivity and safety in under-ground room-and-pillar mining. It performed well as a hopper-feeder for continuous haulage during a coal mine demonstration. Testing in a simulated mine showed that the machine also has good roof bolting capability.

Jan 1, 1987

By Ren G. Dong, Thomas W. McDowell, John Z. Wu, Chris Warren, Dan E. Welcome, Chun L. Dong

Hand forces are important factors for risk assessment of hand-arm vibration syndrome (HAVS).1 Grip force is one of the most important force components in the operation of powered hand tools. A considerable number of studies on grip force have been reported. It is well known that the grip force applied on a cylindrical handle is not uniformly distributed on each axis across the center of the handle cross-section.2 Therefore, maximum and minimum orientations of grip force exist around the handle. Such orientations have not been clearly identified. In a recently proposed international standard (ISO/CD 15230, 2005),3 it is stated that “the direction of the main gripping force is generally parallel to the z-axis defined in ISO 8727.” 4 This assertion is questionable, and further examinations are required. The objective of this study was to establish a fundamental theory on the distribution of the grip force around cylindrical handles. Methods As shown in Fig. 1, the grip force is defined as a vector composed of normal and shear components (FN & FT) in this study. Fig. 2 shows the hand coordinate system defined in this study, together with the ISO systems.1,4 Based on this novel grip force definition, we derived four fundamental properties and a theorem. More significantly, we formulated a novel hypothesis: similar to Mohr’s circle of stress, the normal and shear components can be represented approximately using an ellipse on the plane of the two force coordinates, as shown in Fig. 3. The maximum and minimum grip normal forces are termed as the first principal grip force (F1) and the second principal grip normal force (F2), respectively. Their corresponding orientations are termed as the first principal grip angle (a1) and the second principal grip angle (a2). A series of experiments were conducted to test this hypothesis. Twelve

Jan 6, 2006

By R. W. Huber

Three arc-melted ingots, two of a titanium-7 percent manganese alloy and the third of unalloyed titanium, were forged and rolled into 3/4-inch plate; comparative data were obtained on these processes. The finished plate, part of which was used by the Naval Bureau of Ordnance, was tested for mechanical and other properties. These properties were correlated with sponge purity, forging technique, rolling temperature, and cooling rate from the rolling temperature. For the alloy material, transformation data were obtained, and their age-hardening characteristics were studied. The temperature-impact relationship was established for rolled sections from all three ingots. INTRODUCTION Arc-melted ingots of unalloyed titanium and a titanium-manganese alloy were fabricated into plate under closely controlled conditions by personnel of the Metals and Alloys Section, Physical Metallurgy Branch, Bureau of Mines, College Park, Md. This program was cosponsored by the Naval Bureau of Ordnance. Bureau of Mines interest lay in correlating the processing procedures with the mechanical properties of the finished plate.

Jan 1, 1955

By E. D. Gardner

"Trolley lines used in connection with electric haulage in mines are a source of danger and many lives have been lost by men accidentally coming in contact with the wires. Usually the wires in metal mines are sufficiently guarded to prevent men from touching them with their person or by pieces of steel which they may be carrying or their shoulders, while walking along the level. However, it is difficult to guard effectively the wires at loading chutes along the haulage ways and in spite of safe guards, chute tappers have been electrocuted through loading bars accidentally touching the trolley line.To overcome this danger the Calumet & Arizona Mining Co., at Lowell, Arizona formely used a hinged V-shaped trough made of 1-inch by 6-inch lumber, that was dropped over the wire in front of the chute, when the cars were being loaded. This arrangement interfered with the easy operation of the chute, and a cut-out device for the trolley line was devised by W. R. Gibson, chief electrician for the company. This cut-out is efficient easily constructed and roes not interfere with the operations at the chutes or with the motors operating on the same level.When the cut-out is open the electric current is carried past the gap by an insulated wire on the opposite side of the drift. A hinged board drops down over the ends of the trolley guard when the slide is open and Prevents anything touching the live wires. About ninety of these cut-outs are now in use in the mine,The levels under the scopes are timbered with drift sets placed 5 feet apart, and the loading chutes take up the space between two sets. All trolley wires in. the company's mines are carried 6 feet above the rails and guarded by two 1/2 by 6-inch boards placed on either side of the wire."

May 1, 1921

By Van H. Manning

The term war minerals has been applied t.o those ores and minerals that were largely imported. before the war. Among the mon important of these are manganese, essential for making high-grade steel for munitions and industrial use; graphite, for u,.akin1 crucibles; tin, for plating utAmsils and for bearing-met.al; mereury, used as fulminate t.o explode shells; pot.uh, for making fertilizer and explosives; tungsten and molybdenum, for high-speed t.ool steel; antimony, for hardening bul!et lead; chromite, for tool steel, for tan- , ning leather, and as a refractory lining in furnaces; magnesite, for :refract:A>ry linings; mica, as insulating material; platinum, for the manufacture of sulphuric acid and for electrical apparatus. When the United States entered the war it was clear that every ship would be needed and that the number available for importing minerals would be small. Hence a quick and thorough survey of domestic resources was necessary. . Throughout the war the scope and volume of the war-minerals work increased until it covered practically every mineral that was known t.o be or was liable to be in short supply.

Jan 1, 1919

By J. W. Town

The Bureau of Mines made continuous-circuit beneficiation studies to determine the optimum conditions for concentrating phosphate minerals from the intermediate-and marginal-grade ores of the Phosphoria Formation in southeast Idaho. Intermediate-grade ore was represented by a sample from Georgetown Canyon and marginal-grade ore from the Gay mine near Fort Hall. Two flow-sheets were developed: The first involved roasting, attrition scrubbing, sizing to remove a concentrate, grinding of the oversize, des liming, and flotation; in the other flowsheet roasting was eliminated. Controlled attrition scrubbing was used to remove clay and silt-size quartz particles imbedded in the phosphate pellets without breaking the pellets. The minus 35-plus 200-mesh fraction was removed by sizing as a finished acid-grade concentrate. The plus 35-mesh material was ground in a rodmill to minus 35 mesh and recycled to the attrition scrubber. The minus 200-mesh fraction was des limed at about 800 mesh to remove clay slimes and floated with 3 to 4 pounds of emulsion per ton of feed. The aqueous fatty-acid oil emulsion consisted by weight of 3 parts No.2 diesel oil, 3 parts crude tall oil, and 0.5 part water-soluble petroleum sulfonate.

Jan 1, 1967

By James W. Wade

This paper describing the mining practices at the Tintic Standard mine is one of a series being prepared by the United States Bureau of Mines. In the preparation of this paper each subject has been presented by the engineer in charge. L. R. Dobbs wrote the part pertaining to tae technique of square-set mining, J. M. Snow the part on geology, and M. D. Paine, the part on ventilation. All of the drawings are the work of H. W. Waterfield of the engineering department. The statistics of the Tintic district ware prepared by A. G. MacKenzie. Each writer has attempted to show the difficulties that arise in operating and the practices used to overcome them.

Jan 1, 1930

By P. Wearden, K. Bryner, K. Vrana, V. Castranova, R. Dey, R. Reist, J. Blackford

"Summary: Fibroblast proliferation and enhancement of collagen synthesis are key steps in the development and progression of pulmonary fibrosis. The current investigation presents a fibroblast proliferation assay to detect the release of competence factors from pneumocytes. The specific objective of this study was to define cell culture conditions for fibroblasts that would allow selective detection of competence factors in test media. The results indicate the following: (a) fibroblasts should be cultured for 2 days in plasma-free medium rather than 2% plasma to assure complete quiescence; (b) 1% plasma was optimum for producing progression activity for the bioassay of a competence factor, while 0.5% plasma did not produce sufficient progression activity (yielding false negatives) and 2% plasma often contained significant competence activity (yielding false positives); and (c) fresh plasma should be used since the progression activity of plasma was adversely affected by freezing and thawing. Under these conditions, this bioassay can be employed with either rat or human lung fibroblasts to detect competence factors such as platelet-derived growth factor (PDGF), at levels as low as 25 ng/ml.Fibrotic lung disease, as a consequence of occupational exposure to silica dust. is characterized by the development of concentric hyalinized nodular lesions in the lung and the progressive loss of pulmonary diffusion capacity. Proliferation of pulmonary fibroblasts and enhanced synthesis of collagen by these pneumocytes have been shown to be key steps in the development of chronic silicosis ( 1 ). The regulation of lung fibroblast proliferation by cytokines released from alveolar macrophages may be an important pathogenetic mechanism in the development of the fibrotic process (2). Some cytokines stimulate fibroblast proliferation by activating specific phases of the cell cycle (3,4). In particular, platelet-derived growth factor (PDGF) promotes fibroblast proliferation by inducing the movement of quiescent (G0 ) cells into the G1 phase of the cell cycle (5). Insulin-like growth factor (IGF) and transforming growth factor-P (TGF-P). on the other hand, regulate the rate of transition of fibroblasts from G 1 into the S phase (5,6). These two classes of cytokines have been termed competence and progression factors, respectively. One approach used to examine the release of cytokines from macrophages is the fibroblast proliferation assay in which quiescent fibroblasts are exposed to culture supematants from macrophages exposed to various stimuli. In most of these assays, the supernatant contains fetal calf serum (FCS), which provides the competence factor(s) necessary to facilitate the proliferation of fibroblasts (7-9). Recently, a fibroblast proliferation assay using platelet-poor .plasma [lacking competence factor(s)] as a substitute for FCS bas been described (I 0, 11 ). In this assay, the release of a competence-inducing PDGF-like growth factor from rat and human macrophages can be distinguished from other cytokines that act as progression factors."

Mar 1, 1992

By Paul Hatmaker

Diatomite is the name now generally given to a mineral substance composed of the tiny , skeletal remains of diatoms , which are microscopic , flowerless , water plants related to the algae ... This residuum is essentially hydrous amorphous silica. Common names for diatomite are : Diatomaceous earth , tripolite , kieselguhr , and infusorial earth . Strictly speaking , however , the latter material is not diatomite , as it is composed of the fossil remains of infusoria , which usually do not occur with the diatomaceae . Other synonyms for diatomite are : Diatomaceous silica , kieselmehl , bergmehl , diatomeenpeelite , polirschiefer , moler , molera , molererde , de smid earth , fossil flour , mountain flour , farine fossil , white peat , radiolarian earth , chalk rock, ceyssatite , randanite , and tellurine ; also various diatomite products of individual companies are known by their own trade names . Diatomite should not be confused with fuller's earth , for the two are separate and distinct substances . Bentonite , pumice , and tripoli , have also been used erroneously to designate diatomite . Tripolite , however , is a true diatomite formerly mined near Tripoli ..

Feb 1, 1931

By Alan Mayton, Bertrand Valero, Farid Amirouche

Handling of heavy vehicles such as tractors, trucks and buses require a large roll stiffness which causes large high accelerations at the seat level during impacts. To provide comfort and minimize the energy transfer from the chassis and the seat a pneumatic active seat suspension is proposed. An active seat suspension design and control algorithm under development at the University of Illinois at Chicago, UIC, is being developed and tested. Preliminary results are presented in this paper. The design of a passive suspension typically consists of optimizing the value of two parameters: the stiffness and the damping of the suspension. The general dynamic performance of the suspension is limited to the conditions under which these parameters were obtained. A change in the input conditions might lead to poor suspension and an amplification of the vibration transmitted to the body. The focus of this paper is a robust, semi-active suspension system with a variable controlled damping and using the body response an index measure to minimize the acceleration at the interface of the seat and operator. A summary of existing suspensions, such as MR and ER fluids, and spring loaded and dual valve shock absorbent will be discussed to highlight the need of a semi-active pneumatic suspension system design. Methods A model of the proposed suspension was developed in MATLB (Simulink) and different control strategies for the valve position in relation to the cylinder pressure tested. The effects of stiffening and softening resulting from pressure changes in the cylinder were examined. The vertical accelerations of the seat was computed for different control strategies and configurations of the suspension and compared to the response of a passive seat suspension. A lump -mass model was created to represent the human body including the head, the upper, middle and lower torso as well as the legs. The connective forces between body segments were modeled through modal analysis techniques from previous experiments at the Vehicle Technology Laboratory. ISO standards and absorbed power were used to evaluate the different configuration of the seat suspension system in relation to the dynamic response of the operator. Results Initial results of the semi-active suspension system show a significant reduction in the RMS value of the acceleration of the seat. A reduction of the total absorbed power by the operator is expected to provide an insight into the control strategies adapted in the active suspension.

Jan 6, 2006

By Richard L. Unger

The Crewstation Analysis Programs (CAP) is a package of computer programs that can be used to analyze some human engineering aspects of crewstation design (such as visibility and illumination) that have particular significance in underground mining. It was developed under the U. S. Bureau of Mines (USBM) Health, Safety and Mining Technology program at the Pittsburgh Research Center, Pittsburgh, PA. This manual describes the steps necessary to collect data in the laboratory to develop luminaire profiles for the CAP illumination analysis. It also describes how the CAP Illumination Model calculates illumination. 1.1 How CAP Calculates Illumination 1.1.1 Background -CAP currently includes assessments of visibility and illumination in the surrounding work area. The advantage of using computers for these types of analyses is that many design iterations can be tested quickly and efficiently to learn the effects of changes. This reduces the need for expensive testing using physical mockups. Another advantage is that design ideas can be tested in situations where it would not normally be possible. For instance, the effects of modifications to a lighting system or canopy design on visibility could be tested while the machine remains in service.

Jan 1, 1994

By John W. Buch

Hydraulic cutting tests made on samples of Pennsylvania anthracite (3,700 psi and 260 gpm) were promising enough for the Bureau to establish a full scale experiment in an anthracite mine. Water pressure and quantity for mining anthracite were arbitrarily established at 5,000 psi and 300 gpm (1,000 hp). For full-volume flow, hydraulic pressure is controlled by orifice size with the displacement pump. The hydraulic jumbo was designed for maneuvering on pitches from 0° to 20° in any direction and for a coalbed ranging in thickness from 10 feet 6 inches to 15 feet. All motions of the jumbo are by oil hydraulics. Jet flow is controlled (start-stop) at the face, through an interlocked pushbutton system. One button is in the operator's cab; one, at the pump station; and one (a safety shutoff), near the mining face. To December 1962, 7,400 tons of bed material had been mined at an average rate of 0.800 ton per minute, with an average power requirement of 14.125 kilowatt-hours per ton. In January 1963, the objective was changed from an engineering-development basis to a research basis--to determine, ultimately, the most efficient level of operating characteristics for maximum response, as measured by mining-out rate. This research phase of the project is not yet complete, but conclusions, and the method of arriving at them, will be made the subject of another Bureau publication. It should be noted that as of December 1963 nearly 13,000 tons of bed material had been mined, at rates as high as 1. 3 tons per minute for a complete face advance.

Jan 1, 1965

By A. C. Fieldner

In the course of its investigations on the properties of coal and in rendering fuel-inspection service to other agencies of the Government, the Bureau of Mines has accumulated a comprehensive file of coal analyses that includes data on virtually every coal field of commercial importance in the United States. As knowledge of the composition of coal is potentially valuable to every user of coal, the Bureau publishes its analytical records. Before 1921 such publications contained analyses of coal from all parts of the United States; individual analyses or average analyses of a series of shipments of coal were given with the name and location of the mine producing the coal. Beginning in 1921 the analyses were published by separate States because the quantity of data had become so great. The separate papers published to date, with Bureau of Mines Technical Paper numbers, are as follows: Alabama, 347; Arkansas, 416; Colorado, 574; Illinois, 634 and 641; Indiana, 417; Iowa, 269; Kansas, 455; Kentucky, 30S; Maryland, 465; Missouri, 366; Montana, 529; New Mexico, 569; Ohio, 344; Oklahoma, 411 ; Pennsylvania (bituminous), 590; Tennessee, 356; Utah, 345; Virginia, 365; Washington, 491 and 618 (618, published in 1941, supplements 491); West Virginia, 405 and 626; and Wyoming, 484. From time to time the various papers will be revised to include later analyses and other data. The Bureau of Mines annually receives many inquiries as to the composition of coals obtained from specific localities or, conversely, as to the localities from which a given kind of coal may be obtained. This paper presents a summary, in tabular form, of the composition of commercial coal resources of the country. Specimen analyses are given exemplifying the analysis of coal mined in each coal-producing county, or, where it was feasible, coal from each bed in each county; also, ranges of analyses, within which the composition of most of the coal represented will fall, are given where there were enough analyses to permit satisfactory determination of the ranges. In addition, the degree of metamorphism from lignite toward anthracite of much of the coal is indicated by the classification by rank. This classification reveals to more experienced users of coal some of the general properties of coal, that is, whether the flame will be long or short, whether the coal will cake in the fire, and how it is likely to behave on exposure and in storage.

Jan 1, 1942