Abstract: Since first introduced, the coal mine roof rating (CMRR) has been widely accepted as a tool for geologic characterization and mine planning. This paper discusses the application of the CMRR to another practical ground-control problem: extended cuts. Extended cuts, i.e., cuts greater than 6 m (20 ft) in length, are commonly used with remote-control continuous miners. Extended cuts can greatly increase productivity, but they have been associated with a number of fatal roof-falls. When extended cuts are attempted in weak roof material, the roof may collapse before it can be bolted. Until now, it has not been possible to predict where conditions may not be suitable for extended cuts. In this study, data on the CMRR and extended-cut experience were collected at 36 mines in seven of the United States. It was found that, when the CMRR was greater than 56, deep cuts were routine in nearly every case. When the CMRR was less than 37, extended cuts were almost never taken, and, when the CMRR was between 38 and 56, extended cuts were sometimes, but not always, feasible. The data also show that extended cuts are less likely to be stable if either the entry span or the depth of cover increases. 12 refs., 5 figs., 1 tab.

Abstract: Artificial intelligence research has produced several tools for commercial application. Some of the techniques that are widely used today include neural networks, fuzzy logic and expert systems. Artificial neural networks (ANNs) are excellent predictive, pattern recognition and data analysis tools. In the mining industry, ANN techniques are being used commercially for real-time process-control applications. Modeling of spatial data, ore-reserve estimation, tunnel design, longwall-stability prediction and geologic roof classification are additional applications in which neural networks have been applied successfully. In this study, a standard back-propagation algorithm was used to train a series of neural networks for a real-world predictive task. After training and optimizing the neural network architecture, the performance of the network is measured on an independent validation set. Results indicate a mean error of less than 1% between the actual and predicted values. A neural network model was developed for learning the spatial continuity of a mineral field and, consequently, for predicting sulfur values for given coordinates. The neural network not only performed satisfactorily, but in some cases performed even better than the kriging model. 19 refs., 8 figs., 1 tab.

Abstract: As ideas of sustainable development are being adopted, mining is at great risk of falling behind, as the general public does not regard it as being environmentally sustainable. If mining is to survive, it must change the way in which it is perceived. Mining companies have traditionally taken a paternalistic attitude towards the inhabitants of the countries they have worked in, this must change into an attitude which regards the local inhabitants as stakeholders in the enterprise. Mining will find itself unable to operate anywhere if it is incapable of effectively combining economic, environmental and social goals everywhere it does business. Examples are given.

Abstract: Significant deposits of mineral sands were discovered in Virginia's Upper Coastal Plain in 1989 The Old Hickory deposit is the largest ore body in the state (>2,000 ha) and supports a productive rowcrop agriculture on prime farmlands field experiments were installed on pilot-scale (25 m x 60 m) mining pits in the late summer of 1995 and replicated on an adjacent undisturbed area Half of each mining pit was topsoiled (25 cm) while the remaining half was left as either (1) mixed tails/slimes or (2) re-graded subsoil over tails/slimes to simulate various pit closure scenarios Both non-topsoiled areas received 112 Mg/ha of yard waste compost as a soil building amendment The entire area was ripped/disked to ameliorate compaction and incorporate lime and fertilizer additions The experiment was cropped through a wheat/soybeans/corn/cotton rotation over the 1995 to 1998 growing seasons Taken as a whole, these combined results clearly indicate that mining and reclamation of these prime farmlands will lead to a substantial decrease in rowcrop productivity, at least over the initial years following pit closure and reclamation For the rotation studied, post-mining productivity was estimated by this experiment to be reduced by 23%, 3%, 27%, and 20% for each crop (wheat/soybeans/corn/cotton)more » in sequence For a given crop in a given year, response to topsoiling versus compost addition to the surface varied, and neither treatment appeared superior Corn and cotton yields on the mined land treatments were reduced despite the application of irrigation Cotton quality was also adversely affected by the mining reclamation treatments Results of these controlled experiments are somewhat encouraging However, the implementation of protocols will be complicated in practice if tailings and slimes cannot be re-blended to generate a reasonably uniform final reclaimed surface« less

Abstract: The Longwall Strata-Control and Maintenance System (LoSCo-MS) is a software and data-communication system developed at the University of Alabama. This system integrates real-time shield monitoring, data presentation, analysis and the forecasting of forthcoming events. The main objective of this system is to provide stability information on longwall panels, including excessive shield load, low setting pressure, leg leakage, poor shield performance and imminent maintenance problems. Analyses of various mining and geological parameters were also performed to determine past and present roof characteristics and to forecast roof loading patterns for the following mining cycles, the next periodic weighting, etc. A local coal mine in the Warrior Coal Basin has adopted this system to provide daily evaluation of ground stability and maintenance problems in their longwall panels. Two years of experience with this system is covered in this paper. 4 refs., 10 figs.

Abstract: Results are presented that were gathered during pilot- and field-scale testing of an innovative technology, sulfate-reducing bacteria (SRB), designed to treat and control acid mine drainage (AMD). The project was performed under the Mine Waste Technology Program (MWTP), which is funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by the EPA and the U.S. Department of Energy through an Interagency Agreement. The MWTP is implemented by MSE, Technology Applications, Inc., located in Butte, Montana. Sulfate-reducing bacteria, a common group of anaerobic bacteria, produce hydrogen sulfide and bicarbonate when supplied with sources of carbon and sulfate. Hydrogen sulfide reacts with metal ions in AMD, precipitating them as metal sulfides; the bicarbonate serves to help neutralized the drainage. Pilot-scale testing was performed within eight packed-bed reactors at a temperature representative of a field application of this technology in a northern climate, nominally 8°C. Th...

Abstract: Dense sludge is an innovative and improved method for treating acidic metal bearing streams in a manner which minimizes volumetric generation of sludge for disposal. In the Dense Sludge process, the alkali source is combined with recycled sludge before being introduced into raw water influent, thus forming metal particles with a low affinity for water. The sludge density of clarifier underflow has in some cases increased from the usual 1--2% to nearly 35% solids. This paper will describe installation and operating data from a 9,000 gpm Dense Sludge AMD Treatment Facility at a coal mine in Northern West Virginia.