A wave diffusion geotomography approach to providing subsurface images of mining environment.
Rock Mechanics: Contributions and Challenges: Proceedings of the 31st U.S. Symposium, June 18-20, 1990, Colorado School of Mines, Golden, Colorado. Hustrulid WA, Johnson GA, eds., Brookfield, VT: A.A. Balkema, 1990 Jan; :863-869
In much of the western United States mineral industry waste facilities are separated from the groundwater table by hundreds of feet of unsaturated sands, silts and clays. This is often considered an advantage due to the slow movement of fluid in the unsaturated zone, but by the time contamination is discovered in a groundwater monitoring well, the unsaturated materials beneath the site may have accumulated significant amounts of contamination. Toxic materials stored in the vadose zone can continue to pollute the groundwater for many decades after the source of the original contamination has been closed, reclaimed, or removed. Early detection and quantification of vadose zone contamination is central to protecting groundwater resources, yet there exists no reliable remote sensing technique for vadose zone mapping. The costs for assessing contamination, remedial investigation, and/or cleanup of the large scale mining operations common to the western United States are becoming so great that, when added to mining costs, they often impact the economics of the overall mining operation. More attention clearly needs to be given to improving the costs and reliability of remedial investigations, monitoring and cleanup. Improving remedial investigations and monitoring, hinges upon developing entirely new approaches to subsurface vision. The most common approach at this time is to sample groundwater using boreholes. This approach is expensive, inefficient and largely unnecessary for several reasons. First, borehole sampling although needed for contaminant identification, is a discrete and one-dimensional approach to a nondiscrete three-dimensional problem. Contamination detected by a well may first have traveled from a few feet to several hundred feet under the waste disposal area prior to reaching the aquifer. It may then have traveled from a few feet to several thousand feet in the aquifer prior to reaching the monitoring well. Second, boreholes are particularly unsatisfactory for sampling the vadose zone. Third, boreholes for obvious reasons are not generally placed directly beneath waste facilities where leakage is most likely to originate. Finally, boreholes cannot be placed strategically without detailed knowledge of subsurface conditions. Despite a predominant groundwater flow direction, contamination may have multiple paths and directions.
Rock-mechanics; Mining-industry; Mineral-deposits; Minerals; Mineral-processing; Waste-disposal; Waste-disposal-systems; Fluid-mechanics; Fluids; Pollutants; Pollution; Environmental-contamination; Environmental-pollution; Environmental-protection; Environmental-technology; Toxic-materials; Hazardous-materials; Hazardous-waste-cleanup; Monitoring-systems; Sampling; Sampling-methods; Water-analysis; Water-sampling; Boreholes
Rock Mechanics: Contributions and Challenges: Proceedings of the 31st U.S. Symposium, June 18-20, 1990, Colorado School of Mines, Golden, Colorado
The University of Arizona, Tucson, Arizona