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By Brian G. White, Theodore J. Williams, Jeffrey K. Whyatt

Detailed mapping and examination of the site of a large rock burst at the Lucky Friday Mine, Mullan, ID, demonstrated conclusively that damage was caused by a splitting and buckling failure mechanism initiated by separation of rock into layers along steeply dipping metamorphic shear foliation subparallel to the affected crosscut. The thin tablular layers then buckled into the crosscut from both sides. Rigorous control of the burst by these layers suggests practical measures for avoiding bursts in crosscuts in the future by repositioning and reorienting openings so that splitting and buckling are reduced or precluded.

Montana's coal reserves are estimated to be more than 120 billion tons, 24.6 percent of U.S. reserves. Montana's reserves are the largest in the nation. Coal fields are located throughout the state, primarily east of the Continental Divide. Three of the state's 17 coal fields have producing mines. Coal resources range from lignite to high volatile bituminous; however, most of the coal currently mined is subbituminous. Although Lewis and Clark mentioned the presence of coal along the banks of the Missouri River in Montana in 1805, the first major mine was not opened until 1867, at Chestnut, Montana, near Bozeman. The mine at Chestnut served Fort Ellis until the mine was bought by the Northern Pacific Railroad in 1883. By 1900, underground coal mining had developed throughout the state, primarily to supply fuel to the railroads. In the 1920s, large-scale surface mining began in Colstrip to fuel railroad steam engines. Currently, all coal mined in the state is produced from surface mines. The Office of Surface Mining granted the Montana regulatory program conditional approval April 1, 1980, followed by final approval February 1 1,1982. Montana's Abandoned Mine Lands Program was approved November24,1980, and its emergency program was approved August 18, 1983. A Federal Lands Cooperative Agreement was approved May 8, 1981.

Jan 1, 1992

Predict the spontaneous combustion potential of a mining operation using an expert system computer program.

Jan 1, 1994

By Kent Volkmer, Mark Sanders, Gregory Krohn, Tyler Blake, Daniel Wick, Barry Beith

This report describes a study designed to evaluate a proposed modification in the cap lamp battery cord intented to reduce the incidence of snagging and catching of the cord. A three phase evaluation as performed comparing a prototype with the standard, currently available cord. First, a "pull test" equipment was run. The second evaluation was a body conformity study. The third evaluation involved subjects performing common tasks in a low seam coal mine simulator. The results of these evaluations clearly demonstrated significant safety advantages of incorporating coiled cord into the design of the cap cord. The coil cord presented less of a snagging hazard, allowed the wearer more time to respond to a snag, and transmitted lower levels of force to the helmet when snagged. The research team recommended that cap lamp cords be commercially developed which incorporate coiled cord at the battery and helmet.

Jan 1, 1980

Lower the respirable dust exposure of longwall shearer operators by use of a modified head to tail cutting sequence. Approach Modify the cutting sequence of double-drum shearer operations cutting unidirectionally head to tail, so that the tailgate drum is used to mine the entire coal face except when cutting out at the head. This approach would place the primary dust generating source, the cutting action of the drum, on the return air side of both shearer operators. How It Works Currently, 75% of the double-drum shearers in operation employ a unidirectional cutting sequence. On half of these operations, the primary cut is taken as the shearer travels from the headgate to tailgate ends of the face, with roof support to be advanced on the intake air side of the shearer. Typically, the leading (tailgate) drum is taking a full cut during the head to tail pass and the trailing (headgate) drum is cutting bottom coal. In this mode of operation, the dust generated by the trailing (headgate) drum can spread out into the walkway, and increase the respirable dust exposure of both head and taildrum operators. As an alternative, if the trailing drum is "free wheeling" or cutting minimal coal during the head to tail cut, and bottom coal taken by the tailgate drum during the tail to head clean-up pass, both operators are able to work on the intake air side of the primary dust generating source (drum) except when cutting out at the head. This modified cutting sequence would save wear on the conveyor and help to eliminate overloads, as well as reduce the respirable dust exposure of both shearer operators. This modifcation is only applicable to long-wail operations currently cutting unidirectional head to tail, and to those operations where this unidirectional cut would not produce operating constraints.

Jan 1, 1981

By Erica E. Hall, Robert H. Peters, Charles Vaught, Jon C. Volkwein

Coal Workers Pneumoconiosis is the leading cause of death due to occupational illness among coal miners. This disease is caused by miners’ exposure to respirable coal mine dust. A Personal Dust Monitor has recently been developed to provide near real time feedback to miners regarding the number of milligrams of respirable coal mine dust in the air they breathe. This paper was prepared by the National Institute for Occupational Safety and Health to document coal miners’ reactions to this new device, and how they make use of the information it provides. Structured interviews were conducted with 30 coal miners at four mines. A four-stage conceptual model of miners’ decision processes with respect to how they interpret and respond to the dust exposure numbers from their personal dust monitor is proposed. The stages are: Diagnosis, Action Planning and Intervention, Evaluation, and Institutionalization. The interview responses provide considerable support for the model. Most miners paid attention to Personal Dust Monitor feedback and made efforts to reduce their dust exposure. Their efforts included: changing where they positioned themselves, making ventilation system improvements, and using respirators more often. The 29 miners who reported having experience wearing both the old and new type of dust monitors were asked which dust sampling system they preferred. Eighteen (62%) preferred the new monitors, 7 (24%) preferred existing monitors, and 4 (14%) had no preference. The most frequently cited advantage of the new monitor is its ability to provide relatively quick feedback on dust exposure. Miners provided several suggestions for improving the design of the instrument.

By Gerald T. Homce, Michael R. Yenchek, H. Kenneth Sacks, James C. Cawley

Abstract—Overhead electric power lines present a serious electrocution hazard to personnel in a variety of industries. Overhead lines, typically uninsulated conductors supported on towers or poles, are the most common means of electric power transmission and distribution, and are exposed to contact by mobile equipment such as cranes and trucks. Equipment contacting energized overhead lines becomes elevated to a high voltage, and simultaneous contact by personnel of the “hot” frame and ground can cause serious electrical shock and burns. Industries where risk of these accidents is greatest include construction, mining, agriculture, and communications/public utilities. An estimated 2300 accidental overhead line contacts occur each year in the U.S. This paper describes a practical low-cost concept to detect actual contact of mobile equipment with a high-voltage line and provide a warning. Accident statistics indicate that more than half of the fatalities could be prevented by such a device. Index Terms—Crane, electrical shock prevention, engineering control, mining, mobile equipment, power line.

By John C. Machisak

THIS CHAPTER of the Minerals Yearbook (Volume III) contains overall employment and injury experience for coal mines-bituminous, lignite, and anthracite; coke, petroleum and natural gas; and peat and slag plants; metal and nonmetal mines; sand and gravel operations; stone quarries; metallurgical plants, including metal mills and smelters; and nonmetal mills for 1959. Volume I of the yearbook contains injury experience and employment data in the metal, non-metal, sand and gravel, slag, and quarrying industries, and the milling operations and related plants. Volume II contains the injury experience and employment data in the fuel industries--coal, coke, petroleum and natural gas, and peat. Surveys conducted by the Bureau of Mines were the source of injury and employment data used to compile the tables and furnish information for the accompanying text. Response to the surveys was voluntary except that for coal mines. The Coal Mine Safety Act requires operators of coal mines to furnish the information requested.

Jan 1, 1960

To permit better cap lamp positioning for users of dust helmets. Approach The present design of the dust helmet prevents use of the miner's cap lamp when the front shield is raised, When the shield is raised I the cap lamp is directed at the mine roof or back, making the lamp useless in the event the miner needs to wear his self-rescuer. A flip bracket was designed by the Bureau of Mines to correct this situation. How It Works The safety hat is modified by the addition of lamp clips, a bracket and a hinge on the cap lamp and face shield. Two clips hold the lamp cord firmly to the helmet. When the safety hat shield is raised, compressive force from the lamp cord causes the cap lamp hinge to swing open about 90%, allowing the lamp

Jan 1, 1984

By W. F. Hughes

The thermodynamics of an electromagnetic field-fluid interaction system is discussed. A review of the thermodynamics of linear media (the permittivity and permeability taken as functions of density and temperature) is presented; then an extension is made to nonlinear media (the permittivity and permeability taken as functions of the fields). Expressions for thermodynamic properties and reversible work are derived and the first law of thermodynamics for magnetohydrodynamic flow is discussed.

Jan 1, 1968

As technology evolves, accidents may occur because human-system interactions were not considered adequately in the process. A systematic methodology can be used to evaluate the causes of mishaps and to develop recommendations that will enhance safety. A recent trend observed in underground coal mining is used to illustrate this principle because an underground mine is a dynamic work environment. Mining is characterized not only by frequent geologic changes but by technological evolution that can seriously degrade human performance and compromise worker health and safety The case exemplified in this paper involves implementation of remotely controlled equipment for extended cut mining. Extended cut mining technology evolved with minimal ergonomic consideration even though the change from on¬board to remote machine operation dramatically modified the role of the human component. In response to concern that system interactions should be examined more closely. a methodology was developed to identify hazards.

Jan 1, 1998

By Howard M. Stainer

Jan 1, 1963

By Howard M. Stainer

[Cover Page]

Jan 1, 1963

By Maria I. De Rosa

The U.S. Department of Energy Pittsburgh Research Center2 conducted experiments with mine conveyor belt samples in a 20-L furnace and in a laboratory fire tunnel to measure and compare the major toxic gas concentrations evolved during the combustion of the materials. The toxic gas concentrations, measured simultaneously through a multiport sampling device and treated as yield values, included hydrogen chloride (HO), hydrogen cyanide (HeN), oxides of nitrogen (NO, treated as NO), and carbon monoxide (CO). The data obtained from the two experimental systems were in good agreement. Correlations were developed for the toxic gas yields as a function of the percentage of chlorine (for HO gas), nitrogen (for HCN and NO, gases), and carbon (for CO gas) contained in the original materials. The toxic gas yields were also used to calculate a toxicity index (TI) parameter to assess the potential gas toxicity of belt materials during a fire. Furthermore, the TI and the mass loss burning rate values were used to calculate a toxicity hazard (TH) parameter to estimate the toxic gas hazard produced by a burning belt in a ventilated system. Results show that polyvinyl chloride (PVC) belts released higher HC1 concentrations because of the higher chlorine content; styrene-butadiene rubber (SBR) belts released higher CO, HCN, and NOz concentrations because of the higher carbon and nitrogen contents. The TI's, however, were greater for the PVC belts due primarily to the higher levels of HC1 produced. The fire tunnel data indicate that the SBR belts can bum with higher mass loss rates than the PVC belts, resulting in a potentially higher toxic hazard (higher TH values) even though their TI values were lower than those of the PVC belts.

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

TEST DECK - ALTIMETER SURVEY WITHOUT ALTMETER TEMPERATURE CORRECTION 1 BAS 8: 22 1391 1391 53. 49.

Jan 1, 1977

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

TEST DECK - AITIHETER SURVEY WITHOUT ALTIMETER TEUPERATURE CORRECTION DATA INPUT

Jan 1, 1977

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

1 11 THIS IS A DIGITAL COMPUTER SIMULATION OF THE VENTILATION SYSTEM OF A MINE LOCATED IN WASHINGTON COUNTY, PENNSYLVANIA. THE VENTILATION SURVEY ON WHICH THIS SIMULATION IS BASED WAS RUN FROM OCT. 27-30 AND ON NOV. 2, 1976 IN THE ACTIVE PORTION OF THE MINE INBY COMBS SHAFT AND THE INACTIVE PORTION AFCUND AND INBY DONAHOO SHAFT. FOLLOW-UP SURVEYS WERE THEN RUN ON FEB. 18 AND FROM MARCH 7-11, 1977 TO INCLUDE THE MAIN HAULAGE SYSTEM OUTBY THE ACTIVE AREAS OF THE MINE. ALL SURVEY DATA WAS NORMALIZED TO A STANDARD DENSITY OF 0.075 POUNDS/CU.FT. PRIOR TO THE CALCULATION OF INPUT PARAMETERS FOR THIS SIMULATION. IN THIS RUN, THE ORIGINAL VENTILATION NETWORK HAS BEEN MODIFIED TO INCLUDE NEW INTAKE AND RETURN AIRSHAFTS AT THE WEST MAINS.

Jan 1, 1977

By Lawrence Y. Marks

During the mineral survey of the Bob Marshall Wilderness and study areas by the author in 1971, 1973, 1974, and 1976 (Marks, 1978), the area designated Reservoir-North (RARE II No. H1-485) in January, 1979, (U.S. Forest Service, 1979) was examined, along with other lands adjacent to the earlier study areas. However, the 1978 open-file report covered only areas originally designated for study. The present report on Reservoir-North is based on earlier work. No work has been done in the area since 1976. Mineral Appraisal Reservoir-North RARE II area (No. H1-485) is in the Northern Disturbed Belt which has been identified as having high potential for natural gas accumulations and lesser potential for oil accumulations (Mudge, 1978). Oil and gas lease applications in the area, indicate interest by oil companies.

Jan 1, 1981

To provide a simple means for rapidly checking methane concentrations at working faces in coal mines while remaining under permanently supported roof. The Approach: A light telescopic probe, through which a gas sample can be pumped Into a methanometer, has been developed. See Figure 1 [ ] How It Works: The telescopic probe consists of sections of small stainless steel tubing encased in sections of lightweight fiberglass tubing. When fully extended the probe is almost 19 ft. long; fully closed it is approximately 5-1/2 feet long. It can be used In either of these positions as well as at intermediate extensions. An approved methanometer is clamped to the probe by a support bracket.

Jan 1, 1975

Lower the respirable dust exposure of longwall shearer operators by isolating and con-fining the dust cloud near the face. Approach Install conveyor belt screens at various locations on the body of the shearer to contain and hold the dust cloud toward the face side of the machine. This approach provides a cleaner air split in the walkway, over the shearer operators. How It Works On most longwall shearer sections, the dust exposure of the shearer operators is primarily attributable to the machine it-self. The dust cloud originates at the face, and the exposure of the operators depends largely on how quickly this dust spreads into the walkway. Conveyor belt screens placed on the gob side of the body of the machine can reduce the amount of dust which spreads out into the walk-way. In addition, belting may be installed over any open spaces between the shearer under-frame and the panline to prevent conveyor dust from boiling out into the operator's walkway.

Jan 1, 1981