Abstract

FLITTON, T.  and  PEATTIE, R.. Resource estimation for deep tabular orebodies the AngloGold Ashanti way. J. S. Afr. Inst. Min. Metall. [online]. 2016, vol.116, n.7, pp.601-608. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2016/v116n7a1.

The extreme depths and consequent expense of drilling and sampling the gold-bearing reefs of the Witwatersrand Basin have resulted in limited data being available for estimation of grade ahead of the mining face. There is, however, a wealth of information from mined-out areas of these deposits. This estimation challenge resulted in the development of a unique method of Mineral Resource estimation. AngloGold Ashanti (AGA) utilizes a technique termed macro cokriging (MCK), which allows for the integration of the limited advanced borehole data with the large chip sample data-sets from the previously mined-out areas by adopting a Bayesian geostatistical approach. The MCK process, in short, is the estimation of mixed support size data together with the application of four-parameter distribution models. The gold value estimation for the Carbon Leader Reef (CLR) on the AGA TauTona Mine is used in this paper as a case study of the process and to demonstrate the effectiveness of this technique through production reconciliation. The current method has been proven over the last 20 years and is now an established part of the Mineral Resource evaluation process within AGA.

Keywords : resource evaluation; Bayesian assumption; macro cokriging; mixed support; four-parameter distribution.

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