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Develop a safe, efficient filter for removing diesel particulate matter (soot) from the exhaust of underground mining machines equipped with water scrubbers. Approach The Bureau of Mines and the Donaldson Company, Inc., jointly developed a low-cost, disposable, pleated-media filter (PMF) system. The system is intended for use on Part 36 permissible equipment or other machines equipped with water scrubbers. The PMF is installed downstream of the water scrubber to take advantage of the cool exhaust produced by the water bath. This demonstration system was tested on three Jeffrey 4114 Ramcars and a Wagner LST-5 scoop at Utah Fuel Company's Skyline mine near Scofield, Utah. Figure 1 illustrates a clean filter element being inserted into the canister on the Ramcar. How It Works The PMF system consists of a water trap, an optional over-pressure relief valve, filter canister, and PMF Under normal operations exhaust from a vehicle equipped with a water scrubber is heavily laden with water, especially on immediate startup of the engine. The water trap is designed to remove most of the water droplets from the exhaust before they enter the PMF, thus improving PMF performance. The over-pressure valve is designed to limit the exhaust backpressure by venting off some exhaust gas before the: filter. It is attached to the water trap upstream of the PMF. Figure 2 illustrates and shows a break out sectional view of the location of the PMF on the Ramcar.

Jan 1, 1991

To enhance safety and efficiency when moving large mining equipment under energized trolley lines, and to assist in compliance with Section 75.1003.2, 30 CFR. Approach A system was designed, using established technology, that permits a remotely located circuit breaker to be controlled from the cab of a mine locomotive moving large mining equipment under energized trolley lines. This control consists of setting the desired trip current, automatic or manual tripping, resetting, and voice communications between the locomotive and a remote Circuit breaker location. How It Works According to 75.1003.2, 30 CFR, whenever a piece of off-track equipment (such as a longwall chock or a continuous miner) is moved by rail under energized trolley or feeder lines, power for the locomotive that is moving the equipment must come from only one' circuit breaker. This circuit breaker must be adjusted to permit no more than one-half its rated short-circuit current to flow. The intent is to lessen the danger if an accident should occur, and if the equipment contacts the trolley line. Even so, the danger is great. This half setting can still represent many hundreds or even thousands of amperes, enough to endanger personnel, the equipment, or the mine. The Remote Control System reduces this danger substantially by giving the personnel associated with the move total control over the associated circuit breaker. The system as designed, is intended to be used with portable circuit breakers that are pulled on a small flat car by a mine jeep, and either precede or follow the equipment, depending on the direction of the power. This portable circuit breaker is equipped with a commercially available solid state overcurrent relay and associated shunt. This circuit breaker is connected via heavy duty clamps around an open trolley line tie breaker such that the current through the shunt is also the current in the trolley line. A receiver, interfaced with the overcurrent relay and shunt, completes the remote system.

Jan 1, 1981

By R. W. Nash

This report describes the design and operation of a digital instrumentation package for the Bureau of Mines improved torsion pendulum, a scientific instrument that measures the vibration damping of metallic materials. The new design eliminates manual analog-to-digital conversion, reduces the data acquisition time, and increases the precision of the measurements. The digital output can be coupled directly to a micro-processor or computer to produce the final data in real time.

Jan 1, 1983

To provide a method for locating trapped miners promptly and accurately. The Approach: Develop a wireless emergency system that is intrinsically safe, compact, easy to operate, reliable, sturdy, and economical. How It Works: A (one transmitter has been developed under Bureau of Mines contracts. The transmitter weighs only a few ounces, is powered by a cap lamp battery, arid can be carried on the miner's belt. A compact loop antenna, which could either be carried by the miner or strategically located in the mine, is used to generate a magnetic field that is sensed by a mobile receiver on the surface. When needed, the antenna is deployed to form a single loop. In mines where the overburden is less than 600 feet, a loop of No. 19 wire approximately 30 feet in circumference is normally adequate. This antenna weighs less than one half pound. In deeper mines, a heavier wire and bigger loop is required; a No. 10 wire deployed around a pillar has been used.

Jan 1, 1974

By C. M. Mason

Mechanical mining produces large quantities of very fine coal dust called float dust. The associated increase in hazard requires a reexamination of the Bureau of Mines method of evaluating the incendivity of explosives in coal dust-gas-air mixtures. A technique recently developed by Bureau of Mines laboratories for evaluating the incendivity of explosives in coal dust-air mixtures was applied, with modifications, to coal dust-air-natural gas mixtures. A series of permissible explosives were evaluated by this modified technique. Results indicate that the modified technique could be the basis of a more discriminatory procedure than that presently in use.

Jan 1, 1968

By Robert C. Hickman

"INTRODUCTION Two holes were drilled on the G. S. Stiner zinc prospect, in the Lead Mine Bend area of Union County, Tenn. The holes were drilled in the vicinity of an area of gossan float and were bottomed in the Maynardville formation of the Nolichucky shale. Drilling was started January 24 and completed February 16, 1947. The total footage drilled was 421.2 feet.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative Work, and prepares the final report. The Metallurgical Branch, Cliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The project was under the general supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch, Raleigh, N. C.LOCATION AND ACCESSIBILITYThe prospect is located approximately 20.5 miles southwest of Tazewell, Tenn. It is reached from Tazewell by driving 13.8 miles southwest on State route 33, thence 6.8 miles over graveled roads in a northwesterly direction to Stiner's general store. The drill holes are located in the bottom land northeast of the store (fig. 1 and 2)."

Feb 1, 1948

By M. J. Friedel, D. E. Scott, T. J. Williams

Rock masses in deep level mines are subject to high stresses, which can result in unexpected failure of rock into mined-out openings. Historically, various independent methods have been used to discern the causes of rock bursts and to evaluate stress conditions in rock masses susceptible to violent failure. Personnel from two research centers of the former U.S. Bureau of Mines, Spokane and Twin Cities, investigated a rock burst that occurred in May of 1994 in a rock mass between the 4400 and the 4600 levels of the Sunshine Mine, Kellogg, ID. The team evaluated the current state of stress in the pillar and the most likely cause of the rock burst by studying the seismic history of the pillar, examining the geology, analyzing the available in situ stress data, calculating possible fault-plane solutions for the burst, and performing a seismic velocity tomographic survey. The results of the study showed that post-rock-burst seismicity was concentrated about 15 to 30 m west of and about 15 m above the rock-burst location. The pillar is composed of a very hard sericitic-to- vitreous quartzite of a type rarely found in the mine, but that is often found in other district mines having a history of seismic activity. In situ stress analysis of the pillar and the surrounding rock mass showed a probable stress rotation from northwest-southeast to east-west. Of four fault plane solutions, the most probable was either a left-lateral, strike-slip movement with a compressive principal stress oriented nearly north-south, or a right-lateral, strike-slip movement oriented east-west. Finally, tomographic images showed low-velocity areas (interpreted as areas of low stress) associated with the crosscuts and haulageways, and high-velocity areas (interpreted as areas of high stress) associated with the rock-burst location. High velocities were also found in a planar area oriented in an elongate northeast-southwest direction.

By Linda L. Chasko, Larry D. Stowinsky, Ronald S. Conti

Mine operators often rely on mine rescue teams to save lives during an underground emergency such as an underground fire, explosion or roof fall. It is extremely important that team members are provided with adequate exploration equipment and that training simulations are conducted in a realistic manner. A series of mine rescue training exercises was developed, conducted and evaluated by the National Institute for Occupational Safety and Health (NIOSH) in cooperation with the Pennsylvania Department of Environmental Protection, Bureau of Deep Mine Safety. The exercises were conducted at NIOSH’s Lake Lynn Laboratory during 1995 to 1998 and resulted in improved technology and training for mine rescue teams. For example, existing technologies were identified to help rescue teams during exploration. These included chemical light sticks to identify team members and mark crosscuts and mine materials, strobe lights for mapping out escape ways, and a helmet mounted thermal imaging system to see through smoke. A hands-free communication system showed potential for enhanced communications between team members and the fresh air base. A new high-visibility team lifeline that allows for flexibility of movement between team members was developed. A positive-pressure inflatable escape device (IED) was used to isolate the “hazardous” environment from fresh air and allow rescue team members to traverse through. An inflatable feed-tube partition that can rapidly block large openings such as underground passageways and simultaneously provide a feed-tube for high-expansion foam generators was also deployed for several simulations. During the simulations, mine rescue team members donned self-contained breathing apparatuses (SCBA) and traversed more than 305-m of mine passageways filled with nontoxic smoke. Visibility ranged from 0.3 to 0.9-m. In one area of the mine, a kerosene heater was used to simulate a fire and reduce the oxygen concentration. In another area, a 1.5 pct methane zone was established. The team members searched for "victims,” mapped the passageways, built temporary stoppings and ventilated the smoke-filled entries. The teams indicated that the simulations were challenging and very informative.

By R. V. Ramani, A. S. C. Owili-eger

This report was prepared by The Pennsylvania State University under USBM Contract No. G0111808. The contract was initiated under the Coal Mine Health and Safety Program. It was administered under the technical direction of DMSE, with Mr. G. R. Schottler acting as the technical project officer. Mr. J. A. Herickes was the contract administrator for the Bureau of Mines. This report is a summary of the work recently completed as part of this contract during the period June, 1971 to December, 1973. This report was submitted by the authors on March 31, 1974. Part of the research reported here was originally done on a grant from the Department of Environmental Resources, Commonwealth of Pennsylvania and reported in Special Research Report No. SR-95 (February 25, 1973) of the Coal Research Board, The Pennsylvania State University.

Jan 1, 1974

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

This report was prepared by The Pennsylvania State University under USBM Contract No. H0133040. The contract was initiated under the technical direction of PMSRC, with Mr. Edward D. Thimons acting as the technical project officer. Mr. Frank Naughton was the contract administrator for the Bureau of Mines. This report is a summary of the work recently completed as part of this contract during the period June 30, 1973,to June 30, 1977. This report was submitted by the authors on August 31, 1977.

Jan 1, 1977

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

To cost-effectively reduce noise and vibration in newly manufactured mantrip vehicles. Approach Previous Bureau of Mines research demonstrated that noise controls could be in-stalled on existing mantrip vehicles, thereby substantially lowering noise levels inside the mantrip. Under Bureau sponsorship, a manufacturer of mantrip vehicles agreed to incorporate similar noise controls into a new vehicle during manufacture. Throughout this project, durability, maintainability, and cost were considered to be as important as noise reduction. How It Works The following noise-control features were included in the new mantrip: (a) Suspension Isolation- The suspension components were isolated by inserting elastomeric materials between them and the vehicle frame.

Jan 1, 1982

Reduce the airborne dust generated in a longwall coal face. Approach Reduce the rotational speed and increase the depth-of-cut of the longwall shearer. How It Works An Anderson-Mavor AM500 double-ended ranging drum shearer was fitted with drums specially designed to accept the large picks required for this testing program. Change gears In the shearer allowed rotational speeds of the drums to be set at 35, 45, 55, or 70 rpm. As deep cutting removes larger coal fragments, the specific energy requirements of the operation are reduced and less surface area results. Dust generation and shearer power consumption are also reduced. The lower rotational speed minimizes the fanning action of the cutterheads and thus reduces the amount of coal fines that become airborne.

Jan 1, 1981

By C. P. Fang

"For lower stages of multinozzle micro-orifice impactors, as many as two thousand nozzles are uniformly arranged within a cluster diameter of 1.06 inches. In the impaction region the mass flowrate of the spent air increases along the radius and reaches a maximum at the periphery. This crossflow can significantly deflect the air jets of the outer nozzles, hence the characteristics of impaction changes.Investigators in heat transfer and fluid mechanics have studied the influence of crossflow on jet deflection and found the dimensionless deflection of the jet centerline X/Dn is a function of (S/Dn)(l/m) . only, here X is downstream coordinate measured from the center of the jet orifice, Sis the jet-to-plate distance, Dn is the orifice diameter and m is the jet/crossflow mass flux ratio defined as:"

Jan 1, 1989

Modify conventional mining practices to reduce significantly the amount of material brought to the surface from underground mines, or to ?re-mine? existing surface mine dumps by backfilling empty underground stopes.

Jan 1, 1994

This is the final report on Project CR-102 under the auspices of the Department of Environmental Resources, Commonwealth of Pennsylvania .1 The project was activated on January 5, 1970, with financial support from Bituminous Coal Research, Inc., the Pennsylvania Coal Research Board, and the Water Quality Office of the Environmental Protection Agency (WQO-EPA)2 through Grant 14010 EST to the Commonwealth of Pennsylvania Work on the project was conducted according to the procedures outlined in BCR Research Program Proposal RPP-164R, dated April 24, 1969, and a subsequent Revulsion of Scope, dated February 25, 1970. This report covers the entire project period from January 5, 1970, through March 25, 1971.

Jan 1, 1971

By Andrew B. Cecala, Robert J. Timko, Alexander D. Prokop

Bag loading and stacking processes are the highest dust-exposure job categories in the metal/nonmetal mining industry.1 To cost-effectively decrease respirable dust levels, the Pittsburgh Research Center of the National Institute of Occupational Safety and Health (NIOSH), formerly of the U. S. Bureau of Mines, designed and tested a system called the Bag and Belt Cleaner Device (B&BCD). [ ]

By Gerrit V. R. Goodman, Charles D. Taylor, Edward D. Thimons, Jay F. Colinet

The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces.

Jan 4, 2000

By Tye J. Lasich

This project involved modeling rock masses with varying Rock Mass Rating (RMR) values to determine the degree of instability that develops around an underground opening as a function of RMR. The modeling was performed using Itasca?s UDEC distinct element software, which allows explicit modeling of blocks of rock and how they interact with each other. The analyses included three different orientations of the joint sets, four different joint spacings and three different values of joint strength, which combine for a total of 36 different combinations of model parameters. Two different modes of behavior were observed: local failure of area immediately surrounding the roof and sides of the opening, and deep-seated failure extending a large distance beyond the opening. Quantification of the size of the unstable area that developed provides numerical validation of empirical guidelines used in design of ground support and instrumented monitoring systems.

Jan 1, 2005

By R. V. Ramani, A. S. C. Owili-eger

The quantity of methane emitted into the mine atmosphere and the movement of gas through solid coal and the adjoining country rock are dependent on the physical properties of the medium, boundary con¬ditions, the initial gas pressure distribution, and the combination of natural and mining factors. Functional relationships between these factors are not yet known. Consequently, the development of rigorous mathematical models to predict methane flow into the mine air is difficult and to date no model has been reported which is capable of such a function. Thus far, empirical formulas available for the calculation of gas quantity released from underground sources require too much his¬torical data, not currently available. Again, these estimations are at best only crudely approximate. The numerical methods available have not been made practical enough for industry wide application. Therefore, the development of a relationship amenable to numerical analysis and practical enough for use in the industry would provide the flexibility lacking in analytical approaches. The mathematical models given in equations (7) and (8) are further attempts in presenting practical models for predicting the quantity of methane emission into the mine environment. Equation (7) is the steady state model and equation (8) is the unsteady state model.

Jan 1, 1974