UBC Theses and Dissertations
Ore reserve estimation, Silver Queen vein, Owen Lake, British Columbia Nowak, Marek Stanislaw
The Silver Queen polymetallic vein system south of Houston, B.C., can be treated as a 2-dimensional problem for purposes of reserve/resource estimation. Complexities in obtaining reserve/resource estimates arise from (i) uncertainties in geological interpolation and extrapolation of the vein system, (ii) uncertainties in the distinction between vein and highly altered wallrock in some old drill logs, (iii) complex and multivariable geological character of the vein, (iv) a limited number of exploration drill holes and (v) a different support for drift and drill hole data. Each of these problems has been considered in detail. The study comprises geological analysis, data analysis, point kriging (analysis of thickness and metal distribution) block kriging and comparison of reserve/resource estimation by various procedures including ordinary kriging, inverse squared distance weighting, and polygonal methods. A novel component of the investigation is the use of correlograms (in reality, 1 minus the correlogram) as a substitute for the variogram in geostatistical estimates. This procedure was tested as a means of defining continuity of DDH and Drift assay data of differing support. Ordinary kriging of large polygonal blocks provides metal contents more or less comparable to but locally more conservative than polygonal results reported in a recent feasibility study. Differences are in part due to the use of somewhat different data for the two procedures. The effect of the volume of the selective mining unit on the recovered tonnage and grade is described and limitations of the indirect lognormal method are presented.
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