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- McCready, Richard G., et al.
(author)
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Applications of geophysical logging for dilution control in mining
- 1996
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In: Proceedings of the Symposium on the Applications of Geophysics to Engineering and Environmental Problems. - Wheat Ridge, Colo : Environmental and Engineering Geophysical Society.
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Conference paper (peer-reviewed)abstract
- In mining, waste rock dilution occurs when uneconomic rock is mined and processed with economic mineralized ore. A survey of selected stopes from various Noranda Group mines estimated that aggregate dilution and oreloss stood at 20% and 8% respectively in 1994. Various technologies are being investigated by Noranda Group mines in an ongoing effort to minimize dilution and oreloss. The following three potential applications of geophysical logging have been identified for dilution and oreloss reduction through improved orebody delineation. Increasing orebody sampling at the delineation stage to reduce geological dilution: Diamond core drilling, with geological core-logging, is the most commonly used method for orebody delineation. Unfortunately, the many task-intensive steps and expense of this method constrain the amount of samples one can obtain. However, by allotting an optimum percentage of the delineation drilling budget for geophysical loggin of percussion-drilled holes, increased sampling would occur. Since percussion drilling is significantly cheaper than diamond drilling, more delineation holes could be drilled to better define the ore boundary geometry and, ultimately reduce geological dilution and oreloss. Controlling geological dilution at the production stage: In production, thousands of meters of percussion holes are drilled annually for blasting purposes. However, since no core is recovered in this drilling process, information about the ore-waste contact is seldom acquired. Thus, there is the potential to geophysically log production holes to identify the ore-waste contact for optimal blast design with a resulting reduction in dilution and oreloss. Interpreting crosshole geophysics tomograms: By geophysically logging boreholes that were used in a crosshole geophysics survey, relationships can be developed to correlate logged geology and geophysical properties along the boreholes. These relationships could then be used in the interpretation of crosshole tomograms. The objectives are detection of undiscovered lenses and defining "connectivity" by mapping ore contours between delineation drillholes. Through analysis of data acquired during field tests at Louvicourt Mine operated by Aur Resources Inc. in northern Quebec, the potential of these applications of geophysical logging for dilution control in mining are examined.
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