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The National Institute of Occupational Safety and Health has classified diesel exhaust as a potential human carcinogen. Though standards for diesel particulate matter (DPM) in the work place have not been established, concern for the health of miners is prompting mine operators to consider methods for reducing worker exposure to diesel exhaust. Approach One of many methods for reducing DPM being investigated by the Bureau of Mines is the use of additives in diesel fuel to improve combustion. Research Results Three fuel additives have been tested in Caterpillar and Deutz diesel engines which are similar to types used in underground mines. One iron-based additive containing ferrous picrate had no effect on emissions. A second iron-based additive containing ferrocene reduced DPM between 5 and 45 pet depending on engine operating conditions. The 37-pct reduction for an 8-minute duty cycle, which includes a wide range of transient loads and speeds, is considered to represent in-mine performance.

Jan 1, 1990

To develop a system which will effectively detect and extinguish fires in underground fueling areas while also providing a warning for nearby miners. Approach A system involving optical fire sensors. automatically-released dry chemical and aqueous film-forming fluid (AFFF) fire suppressants, and automatic alarms was designed from off-the-shelf, state-of-the-art components, and was in-mine tested at two mines in the two typical underground fueling area situations: fuel transfer areas and fuel storage areas. How It Works As mines become more mechanized, the number of fire hazards increases since fueling areas are more abundant. Fire hazards are especially serious in deep mines, since escape time is longer. To help solve this growing problem, the Bureau of Mines, in cooperation with the Mine Safety and Health Administration (MSHA) and the National Fire Protection Association (NFPA), has developed and in-mine tested a cost-effective fueling area fire protection system. The system was designed to be rugged enough for reliable, long-term use, yet to utilize state-of-the-art, off-the-shelf components to maintain cost-effectiveness. The system consists of cross-zoned, ultraviolet flame sensors used for quick response to fire, and a dual-agent fire suppression subsystem. A dry chemical is used for fast fire -knockdown," and AFFF (or "light water") is used for long-term, fire-securing capability. The basic components of the system are shown in the schematic illustration.

Jan 1, 1982

By E. G. King

Enthalpy increments above 298 K were determined by the Bureau of Mines for magnesium hydroxide (brucite) between 298 and 900 K by the method of drop calorimetry. Enthalpy and entropy increments from this investigation were combined with other data from the literature to calculate absolute entropies, free energy functions, enthalpies of formation, Gibbs energies of formation, and equilibrium constants of formation from 298 to 900 K. By the use of published PVT data for water, a table of Gibbs energy change was given for the reaction MgO (periclase) + H2O = Mg(OH)2 (brucite) as a function of temperature and pressure.

Jan 1, 1975

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

Develop a user-friendly computer program that permits those interested in mine health and safety to access and analyze on a personal computer (PC) employment, production, and accident data for U.S. coal and metal-nonmetal mines. This software is being designed with a major focus on flexibility and case of use. The Mine Accident Decision Support System (MADSS) will be available for distribution in mid-1994. Currently, the U.S. Bureau of Mines (USBM) is seeking volunteers willing to pilot test a preliminary version of the software and to provide suggestions for its improvement. Background Since 1975, the Mine Safety and Health Administration (MSHA) has compiled large data bases of information about U.S. mines and the reportable accidents, injuries, and illnesses that have occurred in those mines. Employment and production data arc collected on a quarterly basis from each mine and accident information is collected on an incident -by-incident basis. The USBM has compiled estimated costs for each of these accidents using computer models. All of this information is potentially useful to mine health and safety researchers. However, it has been underutilized because it is stored in large mainframe data bases that arc inaccessible to many users and/or are cumbersome and difficult to use.

Jan 1, 1993

Eliminate the need for roof bolter operators and their helpers to work under unsupported roof while setting or removing temporary supports before or during the roof bolting cycle-a task that annually accounts for approximately 20 percent of all roof fall fatalities. Approach The Bureau of Mines designed, built, and field tested an auto-mated temporary roof support (ATRS) that can be carried from place to place on the drill head of a single, fixed-head roof bolting machine (squirmer) used in low coal seams (less than 42 inches thick). How It Works The ATRS is designed for installation on any streamlined squirmer. It consists of a ten? foot-long, steel, wide-flange beam supported by two double-acting, telescoping hydraulic cylinders. A steel sleeve, mounted on the bottom center of the beam, is designed to fit over top of the

Jan 1, 1983

By David P. Lindroth

The Bureau of Mines has developed and successfully tested a hangup clearance module for use in clearing hangups in underground mine chutes and ore passes. The Bureau's tests showed that the hangup clearance module can be effectively used to clear mine hangups. Furthermore, it is believed that clearance using this module is quicker, safer, and more efficient than the method currently used. The hangup clearance module uses a ballistic disk explosive charge that can clear hangups located as far as 50 feet (15.2 m) from the position where the charge is detonated. Mine personnel can therefore set up the module and the charge it contains without being exposed to dangerous areas. This report describes the principles of operation of the module, provides data and drawings for its construction, and gives instructions for its setup and use. The report also summarizes the development of the module, briefly discusses preliminary and underground tests, and lists the current and potential applications of the hangup clearance module to underground mining.

Jan 1, 1982

By Gordon H. Dechman

This Bureau of Mines report presents an iterative approximation method for microseismic source location that was developed to adapt microseismic techniques for rock structure analysis to investigations of surface problems, such as slope failure in an open pit mine. The source location method and two derivative location algorithms are described in detail, and the speed and accuracy of the two algorithms are compared.

Jan 1, 1977

By E. W. Dean, W. A. Jacobs

"The petroleum division of the Bureau of Mines in its laboratory investigations, has had occasions to develop a number of types of electrical heating equipment. It was found that electric heaters could be used to particular advantage in the standard distillation test for gasoline. (Dean, E.W., Motor Gasoline, Properties, Laboratory Methods of Testing and Practical Specifications, Bureau of Mines Technical raper 214, 1919, 33 pages.) In order to assist in rendering this type of heater available for general use, a description of the apparatus developed by the Bureau was published. (Dean, E.W., A convenient electric heater for use in the analytical distillation of gasoline,. Jour. Ind, and Eng. Chem., Vol.10, 1918, page 823.) Shortly after the article was printed a chemical supply house undertook the manufacture of an electric heater suitable for gasoline distillation. A preliminary model was examined and tested by the Bureau and modifications were suggested that were incorporated in the type of heater that was finally marketed.Description of the Bureau of Mines-heater: The electric heater developed by the Bureau has an inverted conical resistance Plament surrounded by a layer of heat-insulating material and mounted in a metal case having a top of hard asbestos (Transite) board. The resistance element is a helix of nickel-chromium alloy wire held by a molded core of alundum. The Bureau heaters are generally of about 330 watts capacity and are used with stock types of regulating rheostats capable of reducing the effective wattage to about 43 the full-load maximum."

Jun 1, 1920

By H. W. Frevert, A. C. Fieldner, S. H. Katz

"The Bureau of Mines, in its investigations of as masks for use in mines and allied industries tests masks that are voluntarily submitted by manufacturers for examination, and issues approval certificates for masks that meet the bureau's specifications. This paper describes the tests that were conducted on an ammonia gas mask by the Bureau of Mines, which successfully met all requirements and tests for ammonia, masks. The mask tested, known as the GMD ammonia gas mask, is manufactured by the Mine Safety Appliances Co., Pittsburgh, Pa. This ammonia gas mask, which forms a pocket over the face and allows breathing through the nose, consists of a face-piece with non-shatter eyeglasses; this is attached by means of a corrugated rubber tube to a canister supported on wearer's chest by a harness. The canister is green in color and is of tinplate construction. It was a disc valve at the bottom to prevent exhalation through the canister. The filling of the canister consists of a specially impregnated activated charcoal, about 750 c.c. in volume and weighing about 520 grunn. The material is supported above the check valve by a dome of wire screen covered with toweling. Above the granular material is a filter of absorbent cotton screens, and all materials are hold firmly in place by pressure from strong"

May 1, 1926

By R. F. Abernethy

The work discussed in this report was done by the Bureau of Mines to develop a method for determining trace amounts of fluorine in coal. Samples of coal mixed with calcium oxide as a fixative agent for fluorine were ashed at 600° C and the residue was fused with sodium carbonate. The melt was dissolved in phosphoric and sulfuric acids and distilled to separate the fluorine) which was determined in the distillate by a SPADNS-zirconium spectrophotometric method. Fluorine determinations of 83 commercial coals ranged from 0,001 to 0.019 percent.

Jan 1, 1967

To improve efficiency in producing clarified water from mineral and metallurgical processing streams containing suspended particles. Approach Particles suspended in mineral and metallurgical processing streams are filtered out by granular magnesium oxide (MgO) used as the medium in deep bed filters. How It Works MgO is substituted for the silica sand or garnet sand currently used in conventional deep bed filters. These filters presently consist of a 24- to-48-inch-deep layer of either silica sand or mixed media, consisting of a stratified combination of anthracite coal, silica sand, and garnet sand. As waste water containing fine solids is percolated through the granular bed, the suspended particles become attached to the filter grains. When MgO replaces sand as a filter medium, the overall filter capacity is generally increased 50 to 80 percent, and no equipment modifications are necessary for filter operation. MgO is unique because it has a positive surface charge in water while most suspended materials are negative. The attraction of these negatively charged suspended particles to MgO enhances filtering performance. As is necessary for all good media, MgO is insoluble and nontoxic.

Jan 1, 1983

By F. E. Spencer

This Bureau of Mines report provides a complete mathematical description of the algorithm employed by a general multiphase chemical equilibrium program developed particularly for the purpose of studying problems in coal combustion, although the generality of the program will allow its application to any equilibrium system in which an appreciable gas phase is present. When applied to coal combustion problems, the program predicts composition and quantity of slag and unconsumed carbon phases as well as calculates accurately the composition of the gas phase including trace species such as free electrons and ions which are important for predicting electrical properties.

Jan 1, 1973

By Rimas Pakalnis, Tom Brady, Lewis Martin

A major focus of ground control research presently being conducted by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is to incorporate weak rock masses (such as are associated with operations in the Carlin Trend in Nevada) into existing design relationships. The original database that led to most of the empirical design relationships presently employed in hard-rock mining was derived from fair-to-good-quality rock. In this study, the relationship between weak rock quality and opening design (non-entry/entry methods) is being investigated. The common factor in all mines is a weak back or wall. This work attempts to provide tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment. Tom Brady (for correspondence - E-mail- thb6@cdc.gov)and Lewis Martin are at the Spokane Research Laboratory, National Institute for Occupational Safety and Health, 315 East Montgomery Avenue, Spokane, WA 99207-2291, USA (E-mail• ljm8@cdcgov); Rimas Pakalnis is at the Mining Department, University of British Columbia, Vancouver, British Columbia, Canada (E-mail: rcp@mining.ubcca).

Improve face ventilation in mines with large cross-sectional entries. Approach Oil shale, salt, and limestone mines typically have large entries. Providing adequate airflow to the working faces of such mines for worker comfort, health, and safety is a substantial ventilation problem. If diesel equipment is used at the face or if a methane hazard exists in the mine, the problem becomes even more complex. To address this problem, a study was conducted under a joint contract between the Oil Shale Committee of the Colorado Mining Association and the Bureau of Mines. The study evaluated two face-ventilation concepts for large-entry mines. Improving Ventilation Two face-ventilation systems were selected for testing of an oil-shale mine, based on results of a cost/benefit analysis. The systems were a free-standing jet fan and a ducted fan operating in the blowing mode. The jet fan was spotted on the intake side in the mouth of the entry being advanced with final positioning, in or out, deter-mined by minimum recirculation. The ducted fan was also positioned in the mouth of the entry being advanced, with its tubing terminating 75 feet from the working face. The mine face entry was a dead heading 55 feet wide, 30 feet high, and 320 feet long. Sulfur hexafluoride (SF.) tracer gas was used to measure the performance of the two systems in diluting mine face pollutants including after-gases from blasting, hot diesel emissions, methane roof layers, and methane emitted from muckpiles.

Jan 1, 1987

By Wilbur I. Duvall

In a previous report, entitled A Gage and Recording Equipment for Measuring Dynamic Strain in Rock, a control circuit for a drum camera was described. The purpose of this control circuit was to provide a means for firing seismic caps, synchronizing the firing of the cap with the opening of the camera shutters and generating an electrical impulse at the instant of detonation. The operation of this circuit depended on the following two characteristics of seismic caps: (1) these caps contain a bridge, which breaks at the instant of detonation, and, the firing delay time of the cap is a function of the firing current. During the course of the Bureau's studies, considerable difficulty was experienced from "firing hash", i.e., spurious vibrations that appeared on the records at the time of detonation. The cause of most of this "firing hash" was traced to the intermittent grounding of the cap leads at the time of detonation. As the cap leads were still connected to the firing battery, the grounding of the leads permitted current to flow through the rock to the gage and to return to the firing battery through the shield on the gage cables. The intermittent flow of current along the cable shield produced potentials on the gage leads that were recorded as the "firing hash." To eliminate this difficulty, it is necessary to remove the firing voltage from the cap leads the instant the cap detonates. This report supplements the previous report and describes an improved circuit that can be used to fire seismic caps, remove the firing voltage from the cap leads the instant the cap fires, control the firing delay time in the cap, and generate reference signals at the time current starts flowing in the cap circuit and at the time the cap detonates. These reference signals can be used to determine the firing delay time of seismic caps and the time at which the seismic wave is generated by the explosion.

Jan 1, 1950

Provide a machine for economically drilling probe holes in coal mines (required where there's a possibility of unmapped, abandoned workings) to check for possible water flood or gas hazards ahead of the face. Approach A lightweight air-powered drill, that mounts on a light-weight frame anchored to the face with an expandable packer, is used to drill one or more probe holes. The anchor installs quickly and will lock the drill in any desired position. How It Works The drill is portable and can be broken down to small components for ease of transportation. One man can carry these sections through restricted access routes to the working place. Components that are separable are the anchor assembly, drill frame assembly, and drill motor assembly. The drilling sequence is as follows: A 2-inch-diameter anchor hole is drilled 2 feet deep. The fixed anchor tube is rubber packer is expanded. A second anchor hole is drilled through a bushing in the anchor frame. The removable anchor tube is inserted and its rubber packer expanded. (This anchoring system withstood pulls of up to 14,000 pounds.) Next, the frame is attached to the anchor with two screw knobs, and the motor is attached to inserted in the hole and the rubber packer is expanded. A second anchor hole is drilled through a bushing in the anchor frame. The removable anchor tube is inserted and its rubber packer expanded. (This anchoring system withstood pulls of up to 14,000 pounds.) Next, the frame is attached to the anchor with two screw knobs, and the motor is attached to the frame with a single locking pin. Installing the anchor and drill takes less than 12 minutes.

Jan 1, 1981

Reduce mine worker dust exposure by capturing airborne coal and quartz dust generated by a continuous mining machine. Approach Install a water-powered scrubber system operating at 1,000 psi on the side of a continuous miner boom. Dusty air under the boom is drawn through the scrubber, and cleaned air is discharged into the face return. How It Works Most coal mines use exhaust face ventilation to send fresh air over the miner operator, and contaminated air behind the line curtain to the section return. The difficulty with exhaust face ventilation is that the line curtain should be within 10 feet of the face for maximum effectiveness. If the line curtain is not extended properly, or water sprays for dust control are poorly installed, dust rolls back toward the operator. A scrubber mounted on the mining machine will effectively reduce this dust rollback and the dust in the return airstream.

Jan 1, 1989

By C. E. Jordan

Under its program of advancing minerals technology, the Federal Bureau of Mines has invented a laboratory apparatus for continuous separation of minerals based on differences in dielectric properties. The separator consists of a rotating drum electrode and a wire screen electrode positioned 3 mm apart. A high voltage applied across the electrodes that are immersed in a dielectric fluid produces a high-gradient electric field. The high-dielectric-constant (K) minerals are attracted to and conveyed through the separator by the rotating drum electrode, while the low K minerals settle through the screen electrode. Several design and operating parameters, such as electrode configurations, the dielectric liquid and its dielectric constant, electrical voltage and frequencies, feed rates, and particle sizes were studied. In addition, 28 different mineral mixtures were tested with the dielectric separator. In typical tests, a sample of rutile and quartz gangue containing 10-percent rutile was concentrated to 62-percent rutile with 94-percent rutile recovery. A second-stage dielectric separation of the rutile concentrate produced a 92-percent-rutile concentrate. The overall rutile recovery for the two-stage dielectric separation was 86 percent.

Jan 1, 1980

By John J. Sammarco

Mining, traditionally a low-tech industry, is now utilizing surprisingly complex programmable electronic (PE) systems. The functional safety of PE-based mining systems is an international issue and concern. From 1995 to 2001, there were 11 PE-related mining incidents reported in the U.S. and 71 PE-related mining incidents reported in Australia. These incidents are due, in part, to unprecedented levels of system complexity. The National Institute for Occupational Safety and Health (NIOSH) is addressing this issue of system complexity by conducting research to develop a quantitative complexity assessment methodology based on Normal Accident Theory (NAT). The methodology models the behavioral interactive complexity at the level of system requirements. A graph-theoretical approach is used for creating quantitative metrics from Software Cost Reduction (SCR) dependency graphs. This complexity assessment methodology will help realize simpler, safer systems that will be easier to validate and verify. The methodology will benefit mining and other industries as well.