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By J. M. Harrington, C. W. Owings

"The transportation of explosives, and especially their distribution from the supply magazines of the manufacturers or dealers to the mines, quarries, or other points where they are to be used, by means of horse-drawn vehicles is an old-time practice, and the records of accidents of the past show this to have been a hazardous undertaking requiring for safety the taking of many precautions not required in the transportation of other merchandise.Displacement of the horse-drawn vehicle by the motor vehicle for the transportation of explosives is increasing rapidly. A consideration of the facts that the vehicle is operated by an explosion engine, using easily vaporized liquid fuel; that the charges in the engine are fired and the vehicle lighted by electricity; and that the vehicle, being operated insulated from the ground, may accumulate static charges led to the conclusion that new hazards are being introduced into the transportation of explosives through the use of motor-operate& vehicles, and that therefore additional special precautions must be taken against these additional hazards.That accidents have already occurred in this use of motor-vehicle transportation is evidenced from the following examples:Recently in California a driver loaded a box of granular powder in the rear of an automobile truck and a box of electric detonators in the front. Suddenly, while traveling along a highway, the explosives detonated, demolished the truck, and blew the body of the driver into small pieces. No evidence was left to show the cause of the explosion, but it is assumed that a jar or other means caused the detonators to fire, and that they in turn detonated the explosive. It should be recognized that it is unsafe to transport detonators and explosives in the same compartment, and this rule should be strictly enforced. At present this rule appears to be either unknown or, at least, frequently ignored.There are usually so many possible causes of ignition or detonation of a truck load of explosives that it is often impossible to state definitely the exact cause in a given case. This is well illustrated in the following account of an accident: A trucking company was hired to haul a truck load of explosives about 200 miles. The driver had had experience in driving trucks of explosives, and it was stated that he inspected the truck carefully before leaving the garage. Eighty 50-pound boxes of explosive were placed in tiers on each side of the truck and 265 25-pound kegs of black blasting powder were placed in the center of the truck. The boxes were placed flat and the kegs were placed on end, arranged in tiers. While the truck was being driven along the highway there was a muffled explosion. When some men, who were about a quarter of a mile away, arrived at the scene the truck was in flames and they could get no nearer than 100 feet. The driver was sitting in his seat and had apparently been killed instantly either by shock or fumes. When the flames were finally quenched, the driver's body was recovered, badly charred. It was, found that several boxes of explosives had been thrown about 40 feet by the initial explosion but were uninjured. A total of half a ton of dynamite was recovered. The cover to the gasoline tank could not be found."

Aug 1, 1930

By Launa Mallett, Charles Vaught, Jr. Brnich

This paper introduces a technique for incorporating employee participation into the prevention component of a contingency plan. Companies sometimes focus so much energy on response that they forget to put resources into the basics of emergency prevention. The training program discussed here was designed to make employees part of the prevention system. Examples of training materials from the program are provided, a sample method for introducing risk assessment to employees is shown, and a strategy to address limited training time using short videos is explained. Methods for tailoring the training to any worksite and for specific risks are also included. The program is being designed and tested by the Pittsburgh Research Laboratory/NIOSH and employees of an underground coal mine. Examples are taken from the implementation of the program at the mine during the summer and fall of 1998. Results of the program evaluation and lessons learned during the implementation are discussed.

By J. Walden, S. Rhoades, R. E. Miller, R. Gibbs, P. Boman

Accelerometers and pressure transducers mounted in suspension components can be used to monitor the ride of haulage trucks. Presently, it is difficult to tell what caused a jolt to the truck using either pressure or acceleration data alone. When information horn a Global Positioning System is recorded at the same time as shock pressures or acceleration data, then the exact location of an event can be determined. Mine management can then determine what caused the jolt to the truck.

By Lloyd A. Morley, Robert Stefanko

The most time-consuming research segment was assembling the ref¬erences. These are provided immediately after the conclusions but are divided into two categories. The first is directly applicable publi¬cations, correspondence and personnel communications. The second listing contains those publications that are not directly tied to the research but where a probable application exists. In both listings, all important USBM publications are provided. The reference numbers used in the report apply only to the first reference portion. Further¬more, it should be noted that all entries are not used but are retained to help anyone who wishes to look further into different or allied areas of this research topic. Explosion-proof enclosures have been researched since approxi¬mately 1906. Even so, little is understood about the mechanism by which they are effective. Due to the voluminous literature published, there is a good probability that the assembled list is still incomplete. The literature search took the following directions. Work was first directed to reviewing the several references assembled by the Department of Mineral Engineering - Mining Section prior to the present project year. As a result, some duplications and inapplicabilities were found and eliminated. The primary sources of the previous search were the commonly available and usually superb library listings, such as Engineering Abstracts. Because these sources have enormous content on all subjects, they were cross-checked in the first semiannual period several times by different individuals to make sure all normally avail¬able literature were uncovered.

Jan 1, 1974

By Charles Enzian

This report is issued by the Bureau of Mines as one of a series dealing with methods of increasing safety and efficiency in mining operations. It is intended purely as a preliminary statement of the present development of hydraulic mine filling as conducted in the anthracite region of Pennsylvania. A discussion of different methods, their variations and modifications, as well as their probable extension as a result of amplified tests of the various roof-supporting materials, will be presented in a future bulletin. The history of the development of the anthracite-mining industry, from the time when the Indian tribes in the Wyoming and Lacka- wanna Valleys first discovered the existence of "stone coal," on through subsequent events-the purchase of lands containing enor- mous deposits of coal for insignificant sums of money, the develop- ment of the first mine, the formation of the first company, the build- ing of canals and railroads-up to the present time when the industry has become of such tremendous importance to the prosperity of north- eastern Pennsylvania and of the Nation itself, is intersprinkled with romance, tragedy, and pathos. The great economic lessons to be learned from a study of mining operations in the anthracite region suggest to the person interested in the efficient utilization of natural resources the need of applying such methods as will make possible the conservation to posterity of this invaluable deposit of coal that has resulted from the operation of the processes of nature during probably hundreds of millions of years. It is the opinion of many prominent mining men familiar with mining operations in the United States and abroad that under certain conditions the most practical way of preventing loss of unmined coal in pillars and of protecting surface property from damage by sub- sidence is by filling the workings with refuse material. This bulletin aims to present a general discussion of hydraulic mine filling, its origin, development, and practicability in anthracite mining.

Jan 1, 1913

By Steven J. Page

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

Jan 1, 2008

By F. C. Trutt, J. Sottile, J. L. Kohler

Presented in this paper is a theoretical review of the relationships that should exist between electrical winding parameters and the mechanical vibration of a-c machine elements under normal and faulted operating conditions. Also included is data from an experimental study that relates stator vibration and bearing vibration to selected winding faults in a synchronous machine. Consideration of these results indicates a significant relationship between electrical deterioration and mechanical vibration and thus provides the motivation for additional study and a basis for future applications.

By K. Rubow, Z. Zhlqun, V. Marple

A theoretical technique has been developed and verified experimentally for determining the aerodynamic diameter of irregular shaped particles. The aerodynamic diameter of a particle is a very important property in determining where that particle deposits in the respiratory tract. Many instruments, such as impactors and cyclones, will determine the aerodynamic size distributions of aerosol particles but few analyze the particles individually. The theoretical approach of our technique is to solve, by use of high speed computers, the three dimensional Navier-Stokes equations to obtain the flow field around an irregular shaped particle of any contour. The computer program will then determine the drag on the particle, and thus the aerodynamic diameter of the particle can be calculated. The experimental approach has been to pass the particles through a centrifuge and collect the particles upon a collection foil. The position of a particle on the foil is an indication of its aerodynamic diameter. These particles were then shadowed in two orthogonal directions and inspected under an SEM. The top view of the particle in the SEM plus the views of the two orthogonal shadows allows one to determine the three dimensional shape of the particle. Studies have been performed on silica, coal and talc particles with aerodynamic diameters in the 1 to 4 um size range. The three dimensional shape, as is determined from SEM analysis was used in the theoretical computer program and the results compared. It was found that in most 'cases the agreement between the experimentally and theoretically determined aerodynamic diameters was within 5%.

Jan 1, 1988

By R. H. Grau

Improving the air quality in metal/nonmetal mines is important in protecting the health of miners. Air quality can be improved in metal/nonmetal mines by developing proper ventilation techniques. Mine ventilation systems require stoppings to direct the airflow and establish pressure differentials throughout the mine. Due to their large size, stoppings in large-opening mines are cumbersome and costly to construct and maintain. As part of its mining health and safety program, the National Institute for Occupational Safety and Health (NIOSH) designed and tested two novel stoppings (Super Stopping and the EZ-Up Curtain Stopping) at its Lake Lynn Laboratory (LLL). The Super Stopping is designed as a long-term permanent stopping for use in the main entries of the mine, while the EZ-Up Curtain Stopping, although very durable, is designed more for portability and ease of installation. This paper describes the design, materials, and construction methods used for these stoppings as well as their performance and durability when subjected to tests simulating actual production face blast pressures.

Jan 1, 2006

By Timothy J. Orr, Michael J. Beus, Frank T. Duda

The technology to enhance safety and control features for mine shaft hoists is being investigated by researchers at the U.S. Bureau of Mines (USBM). The objective of the research is to prevent injuries and fatalities related to hoist and elevator operations. Monitoring and controlling mine hoisting operations will allow hoist operators, inspectors, and maintenance personnel to increase their awareness of potentially dangerous situations and provide controls for safer operations. Process simulation and visualization software, real-time data sensing, and advanced programming techniques are being applied to this problem. Development of reliable and cost-effective sensors and data acquisition interfaces to monitor hoist loads and detect slack rope conditions is underway. Three-dimensional design software was used to visualize mine hoisting to enhance understanding of hoist operations. Quick Basic and Visual Basic (an object-oriented Windows interface) are being used for acquiring and processing hoisting data. Testing and evaluation of components are underway at USBM testing facilities. The resulting system will allow hoist personnel to assess critical operating parameters, such as hoist position, speed, acceleration, conveyance load, and rope tension.

By L. A. SCHOLL, J. K. CLEMENT

Among the problems investigated by the Bureau of Mines the coal- dust problem has received much attention. Several of the bureau's publications deal specifically with the subject. Bulletin 20° contains an account of preliminary experiments of the bureau to determine the explosibility of coal dusts as well as a review of pertinent literature. Bulletin 50 is a report of a laboratory study of the inflammability of coal dust. The first series of coal-dust explosion tests in the bureau's experimental mine at Bruceton, Pa., is described in Bulletin 56, and Technical Paper 56 presents notes on the prevention of dust and gas explosions in coal mines, and Technical Paper 84 discusses the causes of such explosions and describes methods and apparatus devised by engineers of the bureau for preventing and checking them. The present paper is a report of a detailed study of the bituminous dusts of Illinois mines, and is a part of the investigations conducted by the bureau in cooperation with the Illinois State Geological Survey and the department of mining engineering of the University of Illinois./ It is well known that bituminous coals like those found in Illinois yield dusts that may give rise to explosions of great violence. In order that proper methods might be devised for preventing dust explosions in Illinois mines it was considered desirable to obtain accu- rate information on the quantity and character of these dusts. Ex- periments and tests of dust explosions in an experimental mine as well as in a large steel gallery comparable in area of cross section to mine entries have been made by the Bureau of Mines. Similar experi- ments have been made in Austria, England, France, and Germany. Experiments under conditions similar to those of actual mining prac- tice are obviously more conclusive than tests made in a laboratory. On account, however, of the expense, time, and quantity of dust re- quired, it is not practicable to conduct large-scale tests in studying a large number of dusts and recourse must be had to laboratory apparatus and methods. Laboratory,devices for the study of coal-dust explosions have been devised by a number of investigators. Most of these were intended for qualitative tests only. Quantitative methods have been devised by investigators of the English and French mining-experiment stations." In the experiments described in this report, laboratory tests of inflam- mability were made with an apparatus devised by Dr. J. C. W. Frazer, formerly a chemist of the Bureau of Mines. Laboratory tests of inflammability have been made on more than 500 samples of dust from 100 representative Illinois mines. As a result of these tests it may be stated that: 1. The coals of Illinois when ground fine enough yield highly inflam- mable dusts which when suspended in air may give rise to violent explosions. 2. In the majority of the mines of the State the dusts adhering to the ribs are inflammable. In about one-fourth of the mines the quantity of rib dusts present in the entries is sufficient to form an explosive mixture with air. 3. Most of the road dusts are inflammable when ground to a suffi- cient degree of fineness.

Jan 1, 1916

The Ringelmann Smoke Chart fulfills an important need in smoke abatement work and in certain problems in the combustion of fuels. A knowledge of its history and method of preparation is, therefore, of interest to many. Since instructions on its use are not shown on the recent edition of the chart, those included in this revision of the previous Bureau of Mines publication now are a necessary complement to the chart. More detail regarding the use of the chart is included than was given in the earlier version.

By I. AITKENS

Tourmalines are among the most beautiful of all the semiprecious stones, and are unsurpassed even by corundum in variety of hue. The stones most suited to jewelry purposes are those comparatively free from iron. One reason for the fact that the tourmaline has advanced rapidly in public favor in this country is that it is found in California in great profusion and of extraordinary quality. The superb green and especially the pink crystals found at Pala and Mesa Grande in San Diego County, Calif., are deemed superior to tourmalines from all other localities.

Nov 1, 1931

By Steven J. Page, John A. Organiscak, Thomas Mal

Monitoring the miner respirable quartz dust exposure for compliance with U.S. federal regulations is mandatory to protect the health of coal miners. However, there is no technique available for the direct measurement of the respirable quartz dust concentration in the mining environment. The only means to estimate the respirable quartz dust concentration is to perform an analysis of the respirable dust sample collected, which contains both coal and quartz dust as well as other mineral constituents. For samples collected at coal mines, the U.S. Mine Safety and Health Administration (MSHA) utilizes the P7 method for respirable quartz analysis. The objectives of this work are to 1) evaluate the performance of the P7 method on field samples of low quartz mass loadings, 2) evaluate the magnitude of dust mass spatial variability within an enclosed cab environment, and 3) estimate the subsequent propagation of error in calculating the per. centage of quartz over a broad range of mass and quartz filter loadings at a surface coal mine. These objectives were achieved by obtaining surface coal mine dust samples over a 9-month time period in enclosed cabs of three drills and three bulldozers. By measuring weighing precision and using reasonable estimates for sampler variability, the dust mass spatial variability component was calculated by difference. The results show that 1) the P7 method can be precise and linear with quartz mass loadings as low as approximately 5 µmg of quartz, 2) the dust mass spatial variability, even within an enclosed cab environment, is the dominant factor of variability in propagation of error in estimating the quartz content of the obtained dust samples on a percentage basis, and 3) weighing precision is not a significant factor in error propagation. In addition to the enclosed cab samples, samples from eight surface coal mine drills were collected at various locations exterior to the drill cab. Significant data scatter at these outside locations strongly suggests that the ambient dust mass spatial variability has a significant effect on the propagation of error in estimating quartz content of the dust samples on a percentage basis.

By A. J. Farstad, R. G. Olsen

The Coal Mine Health and Safety Act of 1969, passed by Congress in the wake of the disaster at Farmington, West Virginia, led to an extensive study by the National Academy of Engineering of the problems involved in coal mine safety. One of the results of this report and subsequent research conducted by the U. S. Bureau of Mines has been the investigation of electromagnetic techniques for the location of trapped miners after a mine emergency. The Westinghouse Georesearch Laboratory has been involved in both the 2 theoretical and field studies relating to this problem. A compact personal beacon transmitter has been developed which can be attached to and powered by a miner's lamp battery. A compatible lightweight loop antenna package has also been developed which can be easily carried on a miner's belt. This antenna can be quickly deployed on the mine tunnel floor. For the purpose of calculating its electromagnetic fields on the earth's surface, the loop can be considered to be a magnetic dipole buried in the earth. (The earth is assumed to be homogeneous and to have a conductivity of s mhos/m.) The surface of the earth is assumed to be uniformily sloping and the transmitter dipole oriented as in Figure 1. The fields on the earth's surface can be computed by using a superposition of the fields of a 4 vertical magnetic dipole3 and of a horizontal magnetic dipole in proportions which depend on the slope of the terrain. In the case of level terrain a null in the horizontal magnetic 5 field occurs on the surface directly above the dipole. This null is designated as the apparent source location and is the criterion by which the source is located. The criterion was tested at two hardrock mines and two coal mines in the fall of 1972. The apparent source locations were compared to actual locations determined by conventional surveying techniques. It was found that due to nonlevel terrain the apparent and actual source locations differed by up to 13 meters. This discrepancy can be resolved by an examination of the fields of a source beneath uniformly sloping terrain. Figure 2 shows the experimental and theoretical results for a

Jan 1, 1973

By Clyde E. Eilliams

In recent ye.ars much intere,t has been centered on the possibility of pro­ducing alumina from clq, a.nd proposed methods tor the recove:r,v of alumina are appearing constantly in parent lit,erature, As a good· grade of clay contains from 30 t<> 40 per cent of al"WDina, the prospect of tecovering it is alluring, al though obviously ditfieul t. A patent typical of m projected thermal processes is that 0£ Paul Migu.et, (U, S, Patent No, l,376,563) entitled nprocess for the preparation of pure alkaline alu:ninates.'' Re proposes to prepare alkaline a.luminate by fusing clay, lime, and acrap iron with a reducing aget in the electric furnAce, thereby reducing the silica a.r.d formin1s calcium alumina.te and ferrostlicon, The calcium aluminate, being lighter, would. float on top substantially free from foreign oxides, It could. then be tapped ott, cooledf ana later crushed and leached with aodium carbonate solution to torm, by double decomposition, sodium aluminate, and calcium carbonte. The fonMr is soluble and yields readily aluminum hydroxicie. 'l'he ferrosilicon wo'Uld be r,covered as such and sold at a profit.

Aug 1, 1922

The Crow Indian Reservation is located in the southeastern part of Montana, stretching from near Billings, in the center of the state, to the Wyoming border in the south. The Office of Surface Mining&apos;s Casper, Wyoming, Field Office is responsible for regulating mining and reclamation on Crow tribal land. Federal legislation enacted July 11, 1987, authorized the Indian tribes to implement approved Abandoned Mine Land Reclamation Programs. In early 1988 the Crow elected to develop an Abandoned Mine Land Program under the Title IV provisions of SMCRA. The tribe&apos;s plan received final approval on January 4, 1989.

Jan 1, 1992

By William D. Monaghan, Thomas H. Dubaniewicz, Kenneth L. Cashdollar

Emerging laser technologies are quickly gaining acceptance in the industrial workplace. Besides the risk of human exposure, one safety concern with the more intense lasers is the potential for ignition of flammable gases, vapors, dusts, fibers, or flyings often found in hazardous (classified) industrial settings. In underground coal mines, lasers are being considered for remote measurement of explosive methane gas. Current federal safety regulations for underground mines contain no specific guidance for evaluating the safety of optoelectronic components such as diode lasers. The National Institute for Occupational Safety and Health is conducting research to help provide a scientific basis for developing appropriate safety guidelines for optical equipment in the presence of flammable methane gas and/or coal dust. One phase of the study is an experimental evaluation of methane-air ignition by laser heated small particles. Minimum observed igniting powers for laser energy delivered by 200-, 400-, and 800-um core diameter fiber optic cables and directed onto selected targets in methane-air atmospheres were 0.6, L l, and 2.2 W, respectively. Comparisons are made with other ignition phenomena, including heated wires.

By R. V. Ramani, V. T. Burgos, J. A. McClay

Cost Data Library The data retained in the Cost Data Library is of a semi¬permanent nature in that it is held in storage for immediate use with the program although its contents may require periodic evaluation to maintain it in a current status. The library is composed of six arrays containing both technical and cost data. The following description of the library input system provides the information necessary to maintain an active storage file. Array POWERA: FORMAT (8F10.0) - contains the step groupings of the power rate schedule for power cost computations. Four input data cards are required to fill this storage area. Card Column 1 1 - 10 Demand in Kilowatts for the First Step of the Demand Rate Schedule 11 - 20 Demand in Kilowatts for the Second Step of the Demand Rate Schedule y 41 - 50 Demand in Kilowatts for Fifth Step of the Demand Rate Schedule 51 - 60 Maximum Demand Level for this Rate Schedule 61 - 70 Percent Power Factor for this Rate Schedule 71 - 80 Unassigned 2 1 - 10 First Step Demand Charge, $/Kw 11 - 20 Second Step Demand Charge, $/Kw 4¬ 41 - 50 Fifth Step Demand Charge, $/Kw

Jan 1, 1975

By L. C. IlsLey

"The underlying principle of the storage battery was discovered within the memory of many still living, hence storage-battery locomotives, which were made possible by this discovery, represent a still more recent development. The Journal of the Franklin Institute for December, 1883, gives an account of the building of an electrical omnibus by The Electrical Storage Battery Co., of Millwall, London, This, if not the first, was among the first attempts to, use the storage battery as the source of energy for locomotion.During the period 1888 to 1893 occasional attempts were made to apply this idea practically, but not much was achieved along useful lines.. The progress during the next, 15 years was slow, and little success was achieved. Therefore, the last two decades may be considered the successful development period of the storage-battery locomotive.In coal mining, the application of the storage-battery locomotive is chiefly in gathering service in competition with animal or cable-reel locomotives. The locomotive delivers empty cars to the rooms or working places where the coal is being mined and hauls the loaded cars from the rooms. The length of haul depends upon the distance of, the junction point from the active workings of the mine. As a rule the haulage from the junction point to the foot of the shaft or bottom of the slope is done by trolley locomotives, but in some instances where the grades permit this main-line haulage work it: performed by storage-battery locomotives.As the place storage-battery locomotives occupy with respect to safe haulage in gassy mines appears to be misunderstood, it is the purpose of this paper to clarify this point.Those who originally designed storage-battery locomotives had no thought of safety in mind and it is just as well that they did not, as these early types of storage-battery locomotives with open controller open motor, open rheostats, flimsy headlights, and crude wiring were very dangerous electrically and not at' all suitable for use in a gassy mine. These locomotives, however, were placed in mines in which open lights were permitted and they replaced considerable animal haulage. Later they were gradually introduced in mines where closed lights were used, but in most cases these mines were not extremely gassy."

May 1, 1928