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Jul 1, 2003

Mine closing methods should be carefully considered. If not properly sealed, an abandoned mine may continue to produce acid water. Since 60 to 90 percent of the total acid discharged from all coal mines is from abandoned mines,(58) some states require that provisions for sealing be contained in the mining permit application. Closing an operation to prevent harmful mine drainage into nearby runs and streams is a subject of much concern to states as a result of continuing problems from long abandoned mines which were improperly closed.

Jan 1, 1970

By J. M. Stuve

A novel calorimetric solution technique, recently developed at the Bureau of Mines, was tested using synthetic samples of chalcocite (CU2S) and covellite (CuS). The solution of these refractory sulfides was accomplished by oxidation with bromine in a moderately acidic, aqueous solution. The resulting values for the standard enthalpies of formation (?Hf°, 298.15) for CU2S(c) and CuS(c) were -18.1 ±1.1 kcal/mol and -13.3 ±1.1 kcal/mol, respectively. These values are in good agreement with published formation values derived from other methods of physicochemical measurement.

Jan 1, 1982

By Mathew P. Oommen, Jeffrey L. Kohler

Computer-aided loadflow and fault analyses of mine power systems are routinely conducted to ascertain system performance and also to provide information to assist in the protection and coordination of these systems. Three-winding transformers are frequently encountered in mining applications, typically at continuous miner and longwall sections where there exists a need for dual utilization voltages. These transformers are often modeled as a three-bus system neglecting the secondary to tertiary winding impedance and the effect of base changes. This paper analyzes the impact of more accurate transformer models on voltages and fault currents which are realized from loadflow and fault studies of mine power systems.

By M. Beus, R. Iverson, A. Dreschler, V. Scott

This paper describes research to improve safety during transport of ore and waste in underground mines. Field tests are underway in mines in Idaho and Montana. Strains measured on structural support members in an ore pass provided information about total forces acting on the structure as material was dumped into it. Results show that measured static loads were considerably less than actual total weight of the material dumped and that dynamic loads were subject to many factors, such as effects of blasting to remove hang-ups. Comparisons of measurements and computer results using a particle flow code indicated that several difficulties remain before achieving realistic determinations and models of the dynamic effects of particle flow in ort: passes and impact loads on the gates. Impact loads were overestimated in computer analyses as compared to loads measured in field tests. An alternative design approach based on softening the chute and control gate assembly is being proposed.

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.

By Fred Biggs, Walter Utt, Richard Miller

Powered haulage has been, and continues to be, a major source of severe accidents and fatalities at metal/nonmetal surface mines. Between 1986 and 1997, truck drivers accounted for63% of the lost-time injuries in surface haulage. This project was undertaken to reduce the number and severity of lost-time injuries among operators of these trucks. Work involved measuring shock acceleration at a western surface mine during representative work cycles on two types of trucks and collecting data from cab floors using a triaxial accelerometer and from operator seats using a seat pad accelerometer. NIOSH researchers also used the mine’s GPS systems to locate shock events on a mine map in real time. Shock tests were also run at Caterpillar, Inc.’s, proving grounds in Green Valley, AZ, to determine the magnitude of shocks resulting from controlled rock drops onto the bed of a haulage truck.

By Jürgen F. Brune, William H. Schiffbauer

Communication problems are not new. Research in this area goes back as far as 7922 when the US Bureau of Mines performed experiments to detect radio signals from inside their experimental mine in Bruceton, Pennsylvania. Many improvements to mine communications have been made over the years but for any number of reasons the underground coal mining industry has been behind in implementing advances. Present communications systems far underground mines can be hard-wired or wireless. Both types of systems can fail when faced with fires, roof falls, explosions, and power or battery failure. Currently installed wireless communications systems usually employ a special antenna cable called a "leaky feeder" Fiber optic cables are also used in some applications to form a "backbone" for wireless transceivers. Through-the-earth (TTE) and wireless radio systems are less common. Except for TTE systems, most wireless systems require some wire-bound components, which are susceptible to failure during disasters as cable breakage interrupts communications.

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

THIS PROGRAM TRANSFORMS FREE FORHATED BRANCH DATA INTO A FORMAT SUITABLE FOR INPUT TO THE PENNSYLVANIA STATE UNIVERSITY MINE VENTILATION SIMULATOR (PSU/HVS 1. BRANCH RESISTANCES ARE ASSUMED TO HAVE BEEN ALREADY CALCULATED, IIOWEVER THIS PROGRAM CAN BE EASILY MODIFIED TO HANDLE THE ADDITIONAL INPUT DATA REQUIRED FOR RESISTANCE CALCULATIONS IN THE PSU/MVSO THE PROGRAM IS WRITTEN IN FORTRAN IV WITH WATFIV.

Jan 1, 1977

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

By Kenneth P. Klouse

The current rulemaking on mine illumination makes it necessary for mine personnel to have an understanding of the behavior of light. They must be able to understand many terms that are new to the industry and must be familiar with the use of various types of photometers. With this knowledge, the enforcement criteria for mines can be understood and compliance can be maintained.

Jan 1, 1976

By Jami M. Girard, Ed Mchugh

Slope stability accidents are one of the leading causes of fatalities at U.S. surface mining operations. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is currently conducting research to reduce the fatalities associated with slope failures. The purpose of this paper to discuss some of this research and to present potential new technologies for slope monitoring and design. The paper also briefly discusses various warning signs of slope instability, introduces the most common slope monitoring methods, describes the limitations of various slope monitoring systems, and presents some field results using some of this new technology.

By Miklos D. G. Salamon, Jim M. Galvin, Bruce K. Hebblewhite

A series of mine design accidents in the late 1980s resulted in a major research program at the University of New South Wales, Australia, aimed at developing pillar and mine design guidelines. A database of both failed and unfailed Australian underground coal mine pillar case studies was compiled. A procedure was developed to enable the effective width of rectangular pillars to be taken into account. The database was analyzed statistically using the maximum likelihood method, both independently and as a combined data set with the more extensive South African database. Probabilities of failure were correlated to factors of safety. It was found that there was less than a 4% variance in pillar design extraction ratios resulting from each of these approaches. There is a remarkable consistency between the design formulas developed from back-analysis of the two separate national pillar databases containing many different coal seams and geological environments.

Jan 5, 1999

By J. Nielen van der Merwe

For the last 3 decades, coal pillars in the Republic of South Africa have been designed using the well-known strength formula of Salamon and Munro that was empirically derived after the Coalbrook disaster. The database was recently updated with the addition of failures that occurred after the initial analysis and the omission of failures that occurred in a known anomalous area. An alternative method of analysis was used to refine the constants in the formula. The outcome was a new formula that shows that the larger width-to-height ratio coal pillars are significantly stronger than previously believed, even though the material itself is represented by a reduced constant in the new formula. The formula predicts lower strength for the smaller pillars, explaining the failure of small pillars that were previously believed to have had high safety factors. Application of the new formula will result in improved coal reserve utilization for deeper workings and enhanced stability of shallow workings.

Jan 5, 1999

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

The PC version of the program MFIRE contains many improvements and enhancements previously unavailable for the modeling of mine ventilation networks and the interaction of fires with mine ventilation Transient-state simulation with dynamic modifications of the ventilation system and mine, the fire, and resulting POC transport and ventilation alterations are accommodated with MFIRE. MFIRE is more flexible and provides more error checking, and more informational messages about prob¬lems with input files than its predecessor, the MTU-BOM code The desirable features of the MTU-BOM code such as calculation and identification of recirculation, the air to rock heat exchange, and the basing of calculations on mass flow rates have been retained. MFIRE is useful for the planning and analysis of ven¬tilation networks, simulation for emergency planning, and the evaluation of fire detector layout Inquiries relating to this program should be directed to the Bureau of Mines, Twin Cities Research Center, 5629 Minnehaha Avenue South, Minneapolis, MN 55417

Jan 1, 1990

By Sean Gallagher, Thomas G. Bobick

The Bureau of Mines performed a pilot study examining the effects of posture on back strength and Maximum Acceptable Weight of Lift (MAWL) on six healthy male subjects (M = 32 years + 4 SD). Six hack strength measurements (3 static and 3 dynamic) were made while the subjects were kneeling and standing. In addition, these subjects (who were unaccustomed to lifting in these postures) volunteered to participate in a study of psychophysically determined NAWL in both postures. Results of the back strength tests showed a significantly lower peak torque per body weight output in kneeling versus standing hack strength measurements for five out of six test comparisons (p < .05). Subjective estimates of lifting capacity in the kneeling posture were significantly lower than those for the stooped posture (p < .05). The results of tests of hack strength and lifting capacity in these two postures provide useful information to consider in determining the physiological and psychophysical stresses imposed by these

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 provide a practical method to reduce hand and arm injuries during roof bolting operations.

Jan 1, 2000

Objective: To identify and evaluate a durable, flexible, and practical stopping to direct ventilation airflows in large-opening metal/nonmetal mines.

May 1, 2006

To develop a comprehensive, practical method for designing longwall gate entries that considers coal pillar size, mine roof quality, and artificial support in an easy-to-use computer program.

Jan 1, 1995