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By R. Larry Grayson

Barrett EA, Kowalski KM [1995]. Effective hazard recognition training using a latent-image, three-dimensional slide simulation exercise. Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9527. NTIS stock number: PB95-170379. Beus MJ, Orr TJ [1995]. Computer modeling and analysis of the Greens Creek Mine, Admiralty Island, AK. Spokane, WA: U.S. Department of the Interior, Bureau of Mines, RI9530. NTIS stock number: PB95-176418. [ ]

Establish a procedure for reliably determining cation exchange parameters at an in situ mining site. The Problem Predicting the movement rates of pollutants from waste disposal sites requires reliable measurements of cation exchange parameters since cation exchange can retard pollutant movement. Reliable measurements of these parameters are also required for predicting the length of time needed to restore groundwater quality after in situ mining. Cation exchange is otten the controlling mechanism for the replacement of leach solution cations by the cations in the returning ground-water. Unfortunately, laboratory measurements using core samples are of minimal reliability. The uneven clay distribution at most sites produces a high variability in laboratory results. In addition the flow pattern in the laboratory tests is different from that in the field. Approach Bureau of Mines research has developed a field-test procedure that is quick and yields reliable and representative data. A corresponding data analysis procedure was also established in order to verify the' applicability of the computer simulation model of cation exchange used in the analysis, and of the general analysis procedure, with actual field data.

Jan 1, 1986

To reduce accidents associated with transporting, installing or maintaining mine conveyor belts by providing easy-to-use tools for use in specific tasks. Approach The Bureau of Mines, through a re-search contract, developed three devices for use on conveyor belt systems 1) for use in moving and positioning conveyor components. 2) to reduce spillage and clean-up around conveyors, and 3) to lessen the maintenance of the belt system. The Saucer Skid Moving conveyor components using runner nose 1-beam skids is a simple task when the direction of travel parallels the beams. However, when the unit is moved sideways or around corners for final positioning, the web of the beam scrapes the floor with a bulldozing effect. Many strain and sprain injuries hap-pen when mine workers drag the skids into position at this paint. To minimize such injuries, the Bureau of Mines developed a saucer skid five feet in diameter with rounded sides and a flat bottom. Its design incorporates eight reinforced ribs with holes so the component may be secured to the skid, and eight exterior eyelets to which towing chains may be attached. The skid can be easily moved in any direction because its rounded sides slide over the mine floor rather than drag across it.

Jan 1, 1984

By C. H. Elder

An experimental degasification program using a vertical borehole and vacuum pump to drain gas from the gob area of a longwall panel was successful at Bethlehem Mines Corporation, Cambria Division, No. 33 coal mine. Sixty-one million cubic feet of methane has been exhausted during a 9-month period. Daily production time in the panel increased as a result of lower methane levels in the returns. Removal of large quantities of methane in this way and the exclusion of it from the ventilating system will provide reduced cost in mine ventilation and provide a safer environment for the mine.

May 1, 1969

By J. E. Meacham

The U.S. Bureau of Mines investigated recovery of manganese from basic oxygen furnace (BOF) steelmaking slags because the slags represent a large potential resource of a metal for which there is no domestic production. BOF slags were leached using fluosilicic acid, a byproduct of the fertilizer industry. Manganese and iron were extracted as soluble manganous and ferrous fluosilicates while the calcium and magnesium remained in the tailings as insoluble fluorides. Treating the pregnant liquor with sodium chloride, precipitated sodium fluosilicate (Na2Sif6) which was recovered as a byproduct. Manganese and iron were precipitated as hydroxide-carbonate salts with the addition of sodium carbonate to the treated liquor. Recoveries for manganese and iron were 73 to 83 and 67 to 70 pet, respectively.

Jan 1, 1991

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 R. W. Stahl

Increasing use of continuous miners, especially the boring type, has focused attention on the inadequacy of face ventilation in coal mines. The bulk of the machine, the rapid advance of working faces, and the increased liberation of methane from the larger expanse of freshly exposed coal surfaces have created ventilation problems that were unknown with conventional mining equipment. Ignition of gas, especially that caused by machine bits striking hard rock or pyritic inclusions, have increased at an alarming rate. As the mines penetrate beds under thicker cover at an ever-increasing rate of face advance, this problem will probably increase unless face ventilation is improved. A previous survey, described in Bureau of Mines Report of Investigations 5414, Auxiliary Ventilation of Continuous Miner Places, disclosed that auxiliary fans with tubing generally improved circulation of air and removal of gas at the face. The study here reported attempts to examine, face ventilation at various mines and to note any plan or innovation of. air coursing that industry might adopt to reduce the danger of gas ignition. ACKNOWLEDGMENT The mines visited were very cooperative in the study-and-generously supplied any data requested.

Jan 1, 1960

By Ronald D. Hill, Elmore C. Grim

Mining as an extractive process alone is outdated and unacceptable to today's environmentally concerned public. Multiple land use must be considered as well. Only through effective preplanning can the full potential of reclamation result in a lasting asset for future generations. The coal industry is now recognizing that reclamation of mined lands is part of the mining cycle that must be planned and carried out in a timely and orderly manner. It is also finding that planning reclamation in advance of mining is cheaper and more effective than waiting until mining is completed. The decision to open a strip mine must be based on the results of studies to determine if successful reclamation can be achieved and whether the economic benefits to the company will be justified(1). Information regarding the physical, chemical, hydrologic and biologic systems operative at the site must be under- stood or reclamation will be a failure. Working together, engineers, management and reclamation specialists should design the actual mining and reclamation plan before mining is begun.

Jan 1, 1974

By Richard J. Mainiero, Sapko, Marcia L. Harris

Since 1988, there have been thirteen documented incidents in the United States and Canada in which carbon monoxide (CO) is suspected to have migrated through near surface strata into structures or other enclosed spaces as a result of nearby trench blasting or surface mine blasting. From these incidents, there are thirty suspected or medically verified CO poisonings and one fatality associated with these incidents. To better understand the variables contributing to this hazard, the National Institute for Occupational Safety and Health (NIOSH) carried out a small-scale field study to identify key factors that may contribute to the migration of CO through the ground. NIOSH conducted single-hole heavily confined experimental test shots to measure the radial pressure pulse as it propagated through surrounding monitoring holes to determine if a relationship existed between the pressure pulse and resulting CO measurements afterwards. NIOSH also monitored blasts at an airport construction site. Following the detonations, the concentrations of CO, nitric oxide (NO), and nitrogen dioxide (NO2) were monitored for several days in the surrounding satellite holes. The peak CO measurements relative to distances from the shots were compared. Pressure histories and peak particle velocities (PPV) were measured at monitoring boreholes. It was found that the differential pressures recorded within the boreholes give some indication as to the likelihood of CO appearing, whereas the PPV measurements do not seem to be as good an indicator for potential CO migration. In this limited study, changes in barometric pressure had very little influence on removing the trapped detonation products, whereas applying a vacuum to the monitoring holes was effective in reducing the entrapped CO concentration.

Reduce costs of surface mine reclamation by improving bulldozer operating efficiency. Approach A draft power indicating system helps bulldozer operators adjust blade height and other controls for maximum load movement, by continuously indicating the rate at which work is being done. How It Works This system continuously measures both the push of the blade against the overburden, and the true ground velocity of the bulldozer. It multiplies those quantities to determine the real work rate of the machine. The system consists of a velocity sensor, a blade load sensor, processing circuits, and a work-rate indicator. The processing circuits include an analog multiplier which has an output signal representing the draft power (velocity x load = power). The draft power, or pushing power is a measurement of the work rate at that moment.

Jan 1, 1979

Enable mine personnel to determine the effectiveness of and to optimize the mine fire stench warning system without resorting to costly trial and error fire drills. Approach The mine fire stench warning system is used by underground metal/nonmetal mines to warn mine workers of a fire or other emergency. Stench is released directly into the mine ventilation and/or compressed air lines, and its repulsive odor warns miners to evacuate the mine or to follow other established emergency procedures. Unfortunately, since most deep metal mines have complex ventilation systems, some areas of the mine may receive nauseatingly high concentrations of stench while other areas, in more remote locations, may receive no warning or greatly delayed warring at best. The Bureau of Mines, through research, endeavored to solve this problem with a computer modeling system designed to calculate the distribution of odorant by the stench warning system.

Jan 1, 1986

Detemine the elastic properties and structural integrity of a rock mass in situ. Approach An acoustic device that transmits and receives high-frequency seismic waves between boreholes was designed, built, and field tested. How It Works The acoustic cross-borehole apparatus operates by sending a seismic wave from a transmitter in one borehole to a receiver in a second bore? hole which may be located as far as fifty feet away, depending on the wave transmission quality of the rock. By measuring the wave's travel time and the distance between boreholes, the acoustic velocity of the rock mass can be determined. Characteristics of the seismic wave arriving at the receiver (such as the wave velocity, amplitude, and frequency content) are related to the physical properties of the geologic media, as calcu-

Jan 1, 1982

By John C. Edwards

To have the capability to predict the development of localized spontaneous heating within a porous coalbed that is subjected to forced air ventilation or in an otherwise quiescent environment in which buoyancy develops, the Bureau of Mines developed three time-dependent mathematical models, which were used to calculate the temperature increase associated with chemisorption of oxygen by the coal. In each model, spontaneous heating is driven by an Arrhenius first-order reaction between the oxygen and coal. Two models are two-dimensional, and one is one-dimensional. In the first two-dimensional model, a constant-velocity forced convection airflow is specified; and in the other, buoyant flow is allowed to develop in the absence of forced convection. The third model evaluates the airflow from Darcy's law and a specification of the pressure at the surface of a one-dimensional porous coalbed. Numerical computations demonstrated how each model could be used to predict the onset of spontaneous heating when the porous coalbed was subjected to constraints of an imposed internal heat source or a high- temperature airflow. The effects of particle size and coalbed compaction upon spontaneous heating were examined with the third model.

Jan 1, 1990

By C. M. McCulloch

Examination of several coalbeds in Walker County, Ala., Cambria, Greene, and Fayette Counties, Pa., and Raleigh and Wyoming Counties, W. Va., indicates that cleat orientations are similar throughout a vertical sequence of strata. Studies of cleat orientation were carried out in underground mines that are operating in separate coalbeds vertically above one another. The data show that over a vertical separation of 100 to 400 feet, the average difference in coal cleat orientation between mines is 04° for the face and 08° for the butt cleat. Variations of coal cleat direction between coalbeds examined in strip-mined areas show similar values. Cleat orientations measured at outcrops agree well with the directions measured underground, suggesting that the amount of vertical separation between coalbeds has little effect on the resulting differences in cleat directions. The largest variation of cleat directions between adjacent coalbeds occurs where a large horizontal distance separates two sample locations. Cleat orientations for deeper coalbeds are most reliable where the data are taken from directly above.

Jan 1, 1976

By David J. MacDonald

Stability constants, that is, equilibrium constants for complex-formation reactions, have been determined by a titrimetric method for complexes formed by the transition metal ions Ni2+, Cu2+, Zn2+, and Cd2+ with the structurally analogous bidentate ligands N-ethylethylenediamine and 2-(ethylthio)-ethylamine. The sulfur containing ligand was found to be the weaker of the two chelating agents for each of the four metals. Absorption spectra of the individual complexes have been determined in order to calculate their crystal field stabilization energies. The combined results suggest a linear relation between free energy of chelation and ionic radius of the metal ion.

Jan 1, 1972

By Robert R. Stein, Roy C. Bartholomae, William W. Aljoe

This Bureau of Mines report describes in detail the design and operation of a test apparatus for measuring the sound power levels of drills used by the mining industry. The two major components of the test apparatus are a computer-controlled automated drill test fixture (ADTF) and a large (45,000-ft3) reverberation chamber that houses the ADTF. Design specifications and performance capabilities of the ADTF and the reverberation room are given. Initial test results for three types of drills--a pneumatic percussion drill, a hydraulic percussion drill, and a pneumatic rotary drill--are given to illustrate the types of experiments that can be conducted with the test appartus.

Develop new technology to encourage domestic processing of automobile catalytic converters for recovering platinum -group metals. Background Automobile catalytic converters are used to convert pollutants in automobile exhaust into water vapor, carbon dioxide, and nitrogen, About 1 million troy ounces of platinum-group metals arc used each year in the. United Slates to manufacture catalytic converters. It has been estimated that about 60 pct of the used catalytic converters arc being collected. Most of these used catalytic converters were not processed in the United States but were exported to Japan or Europe for processing. In 1991, about 250,000 troy ounces of platinum-group metals were recovered from scrap catalytic converters collected in the United States. Each short ton of decanned catalyst may contain 30 troy ounces of platinum-group metals valued at over $15,000. Development of an economic process for the recovery of platinum-group metals that can be operated on a small or large scale may increase, the percentage of catalytic converters collected and encourage domestic processing to recover a platinum-group metal concentrate. This would significantly decrease the dependence of the United States on imports for these critical and strategic metals.

Jan 1, 1992

By James M. Spear

The U.S. Bureau of Mines and the U.S. Geological Survey conducted a mineral survey of the Black Butte RARE (I area during the summer of 1981. The study area encompasses 17,800 acres [27.8 sq mi (7,233 ha)] along the course of the Black Butte River, 13 mi (22 km) southeast of Covello, California. No mineral deposits were identified by the U.S. Bureau of Mines during this survey. Assay results of samples taken in this area indicate only trace amounts of manganese, chromium, and nickel. No radioactive or fluorescent minerals were detected. No oil and gas, coal, or geothermal leases have been recorded for the study area.

Jan 1, 1982

By R. Pakalnis, Richard P. Curtin, Lewis A. Martin

Instrumented cable bolts developed at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health were used in conjunction with existing ground control to monitor rock mass loads at various field sites (T.G. Soda Ash, Getchell, Meikle, SSX, K-2, and Stillwater). Axial and shear loads were determined by strain gages to levels of instrument accuracy of ±5 N or ±5 microstrain as these loads were transferred to the instrumented cable bolts. These gages were 12.5 mm long and embedded into a remanufactured king wire that replaced the conventional king wire. Cable bolt performance, quality of grout, and installation techniques were also assessed. By using instrumented cables, a mine operator can determine axial load along the cable at predefined gage locations. By monitoring load on and displacement of the rock mass, more effective ground support can be selected and installed, which will lead to safer working conditions for miners.

Provide an environmentally compatible means of producing lead from galena concentrates that replaces the current high-temperature pyrometallurgical primary lead smelting process and supplies pure lead metal within present and proposed Environmental Protection Agency (FPA) and Occupational Safety and Health Administration (OSHA) lead emission standards. Approach The U.S. Bureau of Mines developed an energy efficient and pollution-free leach-electrowinning method for use in recovering pure lead metal and byproducts from lead sulfide concentrates.

Jan 1, 1989