Geostatistics. Volume 2 / Геостатистика. Часть 2

The main developments during four decades of geostatistical applications on the Witwatersrand-type gold deposits are reviewed and critically compared with a view to highlighting the progress made to date. The basic techniques - from the preliminary borehole valuation of mining properties to the block estimating of ore reserves and foreseeable recoveries are analysed and the prospects for methodological improvements are discussed. The techniques examined include the first elementary kriging procedure of regression (Krige, 1952), first spatial structure modelling through the variance-size of area analysis (Krige, 1952), and all the main subsequently developed kriging and variography techniques applied to the Witwatersrand deposits. Data from the original 91 boreholes covering the major part of the Orange free State Gold Field as well as sampling data from Loraine Mine (over 24 000 items) provide the information base for the analysis. The achievements are measured and compared using error variances and considering the total relative profits to be realised from the selective mining of an orebody. <...>