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By Gilbert A. Wray

This report presents the results of a study of the overturning Stability of Front End Loaders and the development of an Obstacle Detector to warn of Obstacles in the blind regions of the vehicle. The contributing factors have been identified, the FEL stability characteristics have been determined and six overturn warning indicators were fabricated and two were field tested in a mine operation over an extended time period. A simplified overturn indicator, based on the principle of sensing wheel load, was designed, constructed and field tested. The principle was demonstrated to be sound, however, the method of sensing wheel load must be revised. An obstacle detector capable of detecting a man sized target at ranges of two feet to one hundred feet was designed. A "Breadboard" device utilizing existing microwave devices was constructed and tested successfully.

Jan 1, 1977

By R. Demont, A. Pranesh, S. Rakheja

Ethical concerns of in-vivo procedures and poor repeatability of non-invasive techniques have been major limitations in estimating vibration-induced spine loads through experiments. The biodynamic models of seated human body exposed to whole-body vibration (WBV) have evolved for defining the frequency-weightings, enhancement of human responses to WBV, and developing anthropodynamic manikins for seating assessment activities. The widely reported mechanical-equivalent models, solely based on through- or to-the-body biodynamic response functions, do not seem to resemble the biomechanical structure and do not yield information on the dynamic loading and deflections of segments of concern, namely the spine. On the other hand, biomechanical models with representative anatomical structure and anthropometry are being attempted to simulate segmental movements and the coupling effects, using Finite elements (FE) or multi-body dynamics (MBD) formalisms, which could provide important insights into the inter-vertebral forces [1]. While the FE models pose considerable complexities primarily related to characteristics of the bio-material properties, the MBD technique with discrete rigid bodies offers the flexibility to create multi-segment models with relative ease and lower computational cost. In this study, a preliminary multibody dynamic model of a seated human body exposed to WBV along the vertical direction is formulated using MSC/ADAMS software. The model validity is demonstrated by comparing selected responses with the available measured data. Methods The seated human is represented by nine rigid body segments, including: head, neck, thoracic and lumbar torso, pelvis, hands and thighs, as shown in Fig. 1. The rigid bodies are coupled through different rotational and translational joints, some of which are force elements to allow vertical translations and sagittal–plane rotations of the segments. The measurements of transmission of vertical vibration through-the-body generally require subjects to voluntarily maintain a vertical head position to reduce head-accelerometer orientation errors. The head–neck–shoulder joint is thus considered to be rigid. The shoulders are assumed to be rigidly attached to the thoracic segment. The torso is made up of three (upper, middle and lower) segments connected by visco-elastic revolute and translational joints to permit relative pitch and vertical motions. The forces and torques generated by the joints are derived assuming linear stiffness and damping properties, which were identified from published studies. The pelvis is connected to the rigid seat by similar elements representing the visco-elastic properties of the buttock tissues. The two thighs are rigidly connected to the pelvis, while the segment masses are chosen from the anthropometric data for the 50th percentile male subject. The initial model parameters for the joints were obtained from [2]. The model was analyzed to determine the force-motion relationship at the buttock-seat interface expressed in terms of

Jan 6, 2006

By Robert L. Lagace

This final report documents the work done by Arthur D. Little, Inc. (ADL) on behalf of the U.S. Bureau of Mines, Pittsburgh Mining and Safety Research Center (PMSRC), on Contract H0122026 (which began in August of 1971). Under this contract ADL provided technical assistance to the Bureau on a task basis on virtually all aspects of the Bureau's programs related to present and planned emergency and operational communications and miner location systems for underground coal mines. The work consisted of independent investigations, analyses, experiments, breadboard and prototype hardware development, workshops and technology transfer seminars on mine communications, and on-going evaluations and guidance related to the Bureau's contracted programs on electromagnetic noise, mine communications systems, and trapped miner location. This final report documents the work in two volumes, Volume I, "Emergency and Operational Mine Commun¬ications," and Volume II, "Seismic Detection and Location of Isolated Miners." The Tables of Contents of both Volumes are included in each Volume.

Jan 1, 1974

By James C. Fowler

This report contains a description of the contract activities performed by ENSCO, Inc. under contract H0292025. The purpose of this project was to prove the feasibility of detecting hazards in a coal seam using a synthetic pulse radar. This work was conducted in three phases. The first was an analysis of the types of errors which might cause problems. The second was to build a breadboard radar and the third phase was to conduct a field test with the system. The work from each phase is discussed and the results of the field tests are presented. These results show propagation of the radar signal through 200 feet of coal along with reflections from 50 feet away. The final section contains recommendations for future development.

Jan 1, 1981

By Howard B. Hamilton

Laboratory performance of mercury filled current limiting devices (CLD) used for high speed switching of DC circuits (600 volts and below, up to 1000 amperes) using a system involving a parallel connected vacuum switch with CLD and an additional series connected vacuum switch was verified in USBM Contract #HO 357079. This report details analytical work and field experimental tests to predict and control voltage surges associated with the high switching speed associated with the switching system. It also details tests conducted to demonstrate the fault current limiting ability of the CLD. Problems associated with designing a fault current limiting system are discussed.

Jan 1, 1978

The objective of this study was two-fold: 1. To perform a world literature search pertinent to the analysis, selection and design of hoisting systems and their components and to codify the search into a literature compendium. The search resulted in a technical data file of over 1500 hard copy items. The compendium index was also suitable for establishing a comprehensive computer-loaded data base on the subject. 2. To develop a comprehensive system of guidelines to cover salient aspects of analysis, selection and design of electrical, mechanical and structural components of a hoisting system with a view to establish parameters for maximum safety and efficiency of operation, installation and revision of the system. 3. Major mechanical components in the hoist and mechanical drive train are considered. Design and specification criteria based on American standards and practices are developed as they apply to typical mine hoist arrangements.

Jan 1, 1988

By Joseph L. Buckley

A total of 55 conveyor belt fire tests were conducted in the Bureau of Mines Fire Test Gallery, located at the Factory Mutual (FM) Fire Test Center West Glocester, R.I. The objectives of these tests were to: 1) determine the fire resistance and burning characteristics of various conveyor belt materials under simulated mine conditions; 2) provide essential data for designing a reliable bench-scale conveyor belt fire resistance test; and, 3) determine fire test conditions that will discriminate between low, moderate and high fire resistant materials. Belts, representative of those which mold he found in underground coal mines were examined under n umber of experimental conditions which included; ignition intensity; air flow rate; ratio of belt bright (h2) to overall gallery height (h1); exposure time; and, belt width. It was found that fire propagation could be achieved for some "fire resistant" belts (complying with the present Schedule 2G standard for approval) when exposed to an Ignition source of =6000 Btu/min for a 15-min period at a belt height ratio of 01.66. There appears to be a dependency of flame propagation on air flow rates and belt width, although the tests performed do not provide a quantitative trend. Recommendations are made for additional work to resolve some anomalous date and to fill voids in the rest program.

Jan 1, 1978

By Paul J. Remington

The field data gathered as part of the measurements described in Volumes I and II were re-analyzed in the low frequency regime (.1 Hz to 1 Hz) where motion sickness normally occurs. These data were compared co the international standard ?ISO 2631 Addendum 2: Evaluation of exposure to whole body z-axis vertical vibration in the frequency range 0.1 to 1.0 Hz." For both underground mining machines and surface mining machines the results showed that one would not expect motion sickness to .be a severe problem. New field data were gathered on the vibration reduction performance of various seat designs found on surface coal mining machines. The vibration during normal operation was measured on the seat using the standard seat pad accelerometer package described in the previous two volumes and simultaneously on the floor of the machine at the base of the seat. Preliminary indications are that the so-called high performance seats used for operator vibration reduction do not offer significant improvement over conventional seats.

Jan 1, 1984

By L. C. IlsLey

"There is an old saying that ""It is too late to lock the stable after the horse is stolen"". Is not this just what is being done by many mine operators today when it comes to buying safe electrical equipment for gaseous and dusty coal mines?The ""open type"" of electrical equipment or even the ""half safe"" type represents the unlocked stable. After the mine disaster, and after men have lost their lives, the lock is put on - that is, safer equipment is installed.For example, an open type of electric coal drill was used in a gaseous mine in West Virginia, This was the probable cause of the death of 27 men. A half safe type of electric coal-cutting machine was used in a gaseous mine in Pennsylvania. This was likely the cause of the death of 36 men. An unapproved, unsafe type of flame safety lamp was used in a gaseous and dusty mine in Utah. This was the all¬eged cause of the death of 171 men. All three disasters happened within the last six months, and seem to have been avoidable if proper equipment had been used.It is understood that more rigid requirements will be enforced in West Virginia. The committee of State mine inspectors made definite recommendation for im¬proving the conditions in the given mine in Pennsylvania. The Industrial Commission of Utah have already issued new orders which will remedy the use of unsafe lamps in that State.These acts and recommendation are all good and will help prevent accidents in those States in the future. Is it not a pity that such recommendations and order were not made a little earlier before the tell of life had been exacted? Is it not a pity that other States will not take these lessons to heart and safeguard their mines before and not after disasters take place?Electric current can cause accidents in five general ways as follows: (1) By shock to persons; (2) by igniting powder; (3) by igniting gas; (4) by igniting coal dust; and (5) by setting fire to inflammable material such as timber and coal. A great many accidents from these causes are preventable if proper care is taken. Most of the accidents caused by sparks and flashes from electrical apparatus would not take place if approved electrical equipment was used. By approved equipment, the writer means equipment that has been tested and formally approved by the Bureau of Mines. So far as known, up to the present time, no disasters have been caused by sparks or flashes from equipment having the Bureau's approval."

Jul 1, 1924

By A. R. T. Denues

[Liquid oxygen explosives are ordinarily made from a carbonaceous absorbent and from liquid oxygen of high purity. These explosives have a limited but definite field of usefulness; their properties have been described in the literature, which includes several publications of the Bureau of Mines, the most recent dealing with fire-retardant treatments.3/ It seems generally conceded that the outstanding hazards in the use of these explosives are their high inflammability and their relative sensitivity to mechanical action. Each of these topics has been studied, and some interesting practical results have been obtained. Treatments have been described that render liquid-oxygen explosives prepared from granular carbonaceous absorbents practically immune to the action of igniting agents representing or exceeding practical hazards in violence.]

Jan 1, 1941

By Jules Gordon

Presents the results of mining tests conducted on a forward rotating bucket wheel excavator designed to continuously mine coal at 1080 tons/hour, Goals of the program are to determine the feasibility of the forward rotating bucket wheel principle as an effective means of reducing fragmentation and loading costs associated with surface mining, with additional benefit in reducing, coal preparation costs and stripping overburden. Tests took place at the Navajo Mine in Fruitland, New Mexico, Results show that the excavator performed as expected and can reduce fragmenting and loading costs up to 80°. Presented are: 1) production machine design specifications and projected economies extrapolated from the test data, and 2) recommendations for further work in dust control.

Jan 1, 1977

By Richard H. Bares

One criterion central to most definitions of reclamation is the restoration of mined lands to their original productive potential. This is often difficult to achieve on mined lands in the Northern Great Plains because of the rigorous climate (Bares 19;2) and various soil related problems including sodicity, salinity, soil permeability, low organic matter and plant nutrient deficiencies (Malakondaiah and Safaya 1982). Field study sites were established on recontotured mined areas during the early 1970's (prior to the topsoil mandate) in which several amendments were tested for their ability to improve spoil/topsoil conditions and, hence, increase plant production. Physical and chemical properties of these control (untreated) and amended spoils and topsoils have been summarized (Safaya et al. 1982). A number of grass and legume species combinations were studied. The general effects of one time (prior to seeding), single rate (approximately 100 mT ha-1) application of leonardite and/or slack coal to spoils and topsoils was the reduction of grass dry matter yields (NB 1 test site: dry matter yield (DMY) without slack was 110 g m 2 yr I ; DMY with slack was 80 g m -2 yr 1 I and the promotion of legume establishment and yield (SB test site: DMY without leonardite was 13 g m 2 yr -1; DMY with leonardite was 93 g m 2 yr 1). On South Beulah topsoil, treated with leonardite, production of weedy species was remarkably lower than that without leonardite (SB test site: DMY without leonardite was 252 g m - yr -1; DMY with leonardite was 177 g m 2 yr 1). The general effect of commercial fertilizer applied one time prior to seeding (rates ranging from 9-13-0 to 44-1 12-28 kg ha-1 of N-P-K) was to increase plant production during the first two to three years after which the effect disappeared. This effect was much more pronounced on spoils (NB I test site: DMY on spoils without fertilizer was 53 g m -2 yr -1; DMY on spoils with fertiliser was 132 gm -2 yr -1). Weedy species accounted for most of the biomas, production during the first growing season. Three of the test sites were designed to study plant production on topsoils and spoils. Establishment and production of grass species were comparatively better on topsoils (30 cm in depth) than on spoils while legumes were most successful on the soils (Center test site, 1979; DMY of grasses on topsoil was 170 g m 2 yr -1 DMY of grasses on spoils was 52 g m -2 yr -1; DMY of legumes on topsoil was 20 g m -2 yr -1; DMY of legumes on spoil was 191 g m 2 yr -1). Total plant production on topsoiled (302 m thickness) plots at the South Beulah site (DMY in 1979 of 269 g m 2 yr 1) was comparable to that of native western wheatgrass prairie (DMY of 262 g m -2 yr -1). An experiment was conducted to find out if time of planting would have any effect on establishment of grasses on spoils. It was fund that late fall seeding was superior to spring planting for establishment of wheatgrasses at NB 3 test site (Control Plot, 1975: DMY on spring-seeded was 1 g m -2 yr - 1; DMY on fall-seeded was 55 g m -2 yr -1). In general, wheatgrasses (slender, streambank, thickspike and western) yielded the most aboveground biomass of all the grass species tested; yellow sweetclover was the most successful legume. Yellow sweetclover established and was productive on both spoils and topsoils but only where competition with grasses was apparently minimal. Durar hard fescue established and thrived on topsoil but dry matter production was low compared to that of wheatgrasses. Emerald crown-vetch demonstrated a potential for growth on spoils where water conditions were adequate, whereas side-oats grama, prairie sand-reed, alkali sacaton, and bird's -foot trefoil demonstrated only sporadic success. Little bluestem did not become established at any of the test sites. Peak production of the planted species, especially grasses, was generally reached by the second week of July. Legume and weed production continued to increase into late August.

Jan 1, 1982

By R. G. Bottge

To better understand those factors which increase mining costs in Alaska, a Bureau of Mines study was conducted to compare the estimated costs of operating a 100,000-tpd open pit copper mine located on a hypothetical ore body in the Lake Clark area, Alaska, with the costs of mining a similarly sized hypothetical copper ore body near Tucson, Ariz. The information derived should be beneficial to the State and Federal governments in appraising the potential for development of large, low-grade porphyry copper deposits in south-central Alaska. Conventional mining and concentrating methods were assumed, and capital and operating costs were derived using flowsheets and standard costing methods. The total price required for copper mined in Alaska and Arizona was $1.12 and $0.63 per pound, respectively, plus or minus 20 percent. These values were obtained assuming no leaching of low-grade copper, recovery of gold, silver, and molybdenum as byproducts, 100-percent equity financing, and a 12 percent discounted cash flow rate of return. The average domestic and international prices for copper in July 1973 were $0.60 and $0.916 per pound, respectively. The existence of a developed transportation and power system in Alaska would have reduced capital and operating costs subs tantially. The required price for copper would have declined from $1.12 to $1.05 per pound, plus or minus 20 percent.

Jan 1, 1974

By Wilbur I. Duvall

In a review of so 40 papers on damage to residential structures resulting from blasting, only 3 were found that present data on the observed amplitude and frequency of the vibration levels produced by blasting together with an observed degree of damage to a residential structure. The data from these three reports have been analyzed statistically to determine if one of the quantities, displacement, velocity, or acceleration, is more reliable than the others for estimating the degree of damage to a residential structure. From this analysis the conclusion is drawn that a given degree of damage to a structure is most closely related to the magnitude of the particle velocity of the wave motion passing thru the earth at the structure location. On the average, only minor damage it observed for peak particle velocities of 5.4 inches per second, and major damage is observed for peak particle velocities of 7.6 inches per second. When the spread of the data is taken into consideration, the following statement can be made: Wave motions that have a peak particle velocity in excess of 2 inches per second have a fair probability of producing some damage to structures, whereas wave motions that have a peak velocity less than 2 inches per second have a very low probability of causing any damage. Therefore, the recommendation is made that vibration levels in the vicinity of residential structures should be maintained below a peat particle velocity of 2 inches per second. The above criterion for safe blasting is considered to hold over a wide variety of soil and rock conditions because the original data were obtained for a wide range of soil and rock conditions and on various types of residential structures. INTRODUCTION Ever since explosives were discovered and developed for mining purposes, there has existed the problem of what effects the air and ground vibrations resulting from blasting have on structures of various types. This problem is

Jan 1, 1962

By David L. Veith

This Bureau of Mines bibliography of U.S. and Canadian literature pertaining to revegetating coal-mined lands contains 805 references published from 1977 to 1984. Each reference is evaluated by keywords, providing the reader with a means of rapidly sorting through the references to locate only those dealing with the coal mining region and subject of interest. All references are annotated. Other sources of information are given, including Office of Surface Mining (OSM) and State reclamation agencies and other published bibliographies.

Jan 1, 1985

By L. D. Johnson

On a project which is to develop a system to suppress coal dust explosions, a facility has been built and several devices tested. The facility is a 317-foot, 4.5-foot diameter shock tube and to date 53 tests have been carried out with methane-air and methane/coal dust-air as the explosive mixtures. Suppression of slowly propagating (up to 300 ft/sec) flame fronts has been successfully carried out on two tests using the dry chemical extinguishing agent Purple K. Delivery of the material directly into the flame front Seems to be required if effective suppression is to be accomplished.

Jan 1, 1972

As a result of early experiments in underground mine illumination, the Bureau of Hines recognized the need for additional experience with the underground lighting of coal mines having low seam thicknesses. There was already experience with tile illumination of coal mines having higher coal seams, and this contract with Ocean Energy Inc. (OEI) was undertaken to contribute to the "low coal" experience. For the purpose of this contract, a "low coal? mine is defined as one having less than 45 inches of overall headroom in the working places. As a practical limit, 26 inches was the minimum coal seam thickness to be encountered in this program. In one instance, the maximum coal seam thickness was eight to ten feet, however, this particular work was at the direction of the Technical Project Officer (TPO) by virtue of the unique type of lighting arrangement that was to be evaluated which would be useful for low coal. At the outset of the contract, three major tasks were established. The first two tasks involved the installation of permissible fluorescent lighting equipment at two low coal mines. The intention was to illuminate mining sections in each case consisting of one or more machines. The third task was to illuminate a variety or mining equipment including a longwall. For the purpose of this report, the fol-owing identifies the particular installations associated with each task.

Jan 1, 1976

By Charles L. Kusik

A study was conducted for the Bureau of Mines, U.S. Department of the Interior, to provide information which will lead to an increase in the recycling of mineral materials, in order to help conserve the Nation's mineral resources. Data were collected on energy requirements to recycle prompt industrial and obsolete scrap for nine metal commodities: Iron and steel, aluminum, copper, zinc, lead, stainless steel, titanium, tin, and nickel and nickel alloys. Major process routes for recycling were considered, starting from the first collection point through scrap preparation, transportation, smelting and/or refining to the molten metal, ingot, or other semi- finished form approximately equivalent to a primary metal of a similar composition. Available data for 1976 were collected on the amounts of each metal commodity recycled by major scrap categories. In addition, energy requirements were estimated for separating municipal solid wastes into four major categories: Refuse-derived fuel, and magnetic, aluminum, and glass cullet fractions. Finally, areas of research were identified to enhance recycling and/or increase the efficiency of energy use.

Jan 1, 1978

By Robert L. Lagace

This final report documents the work dune by Arthur D. Little, Inc. (ADL) on behalf of the U.S. Bureau of Mines, Pittsburgh Mining and Safety Research Center (PMSRC), on Contract H0122026 (which began in August of 1971). Under this contract ADL provided technical assistance to the Bureau on a task basis on virtually all aspects of the Bureau's programs related to present and planned emergency and operational communications and miner location systems for underground coal mines. The work consisted of independent investigations, analyses, experiments, breadboard and prototype hardware development, workshops and technology transfer seminars on mine communications, and on-going evaluations and guidance related to the Bureau's contracted programs on electromagnetic noise, mine communications systems, and trapped miner location. This final report documents the work in two volumes, Volume I, "Emergency and Operational Mine Communications," and Volume II, "Seismic Detection and Location of Isolated Miners." The Tables of Contents of both Volumes are included in each Volume. Phase I of the contract was devoted to performing an in-depth assessment of electromagnetic noise measurements taken by several contractors and other investigators, and then defining a new noise measurement program and instrumentation system tailored to obtain the necessary but missing noise data. These data are required for use in the design of new emergency and operational communication systems. This work, and the follow-on coordination and guidance activities of ADL on this noise measurement program in subsequent phases of the contract, are treated in Part One of Volume I.

Jan 1, 1974

Coal, America's most abundant fossil fuel, is expected to play a key role in our pursuit of energy independence. A substantial increase in coal exploitation will be required if we are to fulfill our future energy needs. It is essential that new developments continue if stable coal prices are to be achieved and maintained. The challenge of the mining industry is to continue these developments in the face of problems related to increasing labor costs, inflation and environmental restoration. With expectations of increased activity in surface coal mining, the U.S. Bureau of Mines has authorized this study to determine the preliminary economic and technologic feasibility of underspoil haulage in area strip coal mines and to identify geologic and geographic areas where such a system could be used. These objectives were met by literature search, data-gathering visits to several active area strip mines and by analyzing various haulage systems that were superimposed on three model mines. Potential advantages of such a system include: 1) improved mine design; 2) lower mine operating costs; 3) improved land reclamation; 4) lower manpower requirements; 5) lower mobile equipment requirements; and 6) smaller, less sophisticated maintenance facilities.

Jan 1, 1975