Geostatistics versus inverse distance squares in ore reserves estimation: comparative case study in copper ore body in Cyprus

Abstract

The ‘Phoenix’ copper ore body is located in Cyprus Island. Its reserves were initially estimated by inverse distance square (IDS) algorithm. Ore extraction begun in 1996 and ever since the owner company keeps a detailed file of blast hole samples analyses. These data are used to for a continuous check of the validity of estimation. Even tough sampling was systematic and dense, the results of these checks revealed small discrepancies between the ore body model and reality and therefore it was decided to employ geostatistics to possibly improve the estimation quality even more.

The two resulting models were compared to reality inside the exploited area and showed that no substantial improvement occurred due to the employment of geostatistics. The above is in agreement to recent theoretical results which state that, when the sampling density is greater than a critical value, geostatistics and deterministic interpolation methods give similar estimations. The ‘Phoenix’ copper ore body is located in Cyprus Island. Its reserves were initially estimated by IDS algorithm. Ore extraction begun in 1996 and ever since the owner company keeps a detailed file of blast hole samples analyses. These data are used to for a continuous check of the validity of estimation. Even tough sampling was systematic and dense, the results of these checks revealed small discrepancies between the ore body model and reality and therefore it was decided to employ geostatistics to possibly improve the estimation quality even more. The two resulting models were compared to reality inside the exploited area and showed that no substantial improvement occurred due to the employment of geostatistics. The above is in agreement to recent theoretical results which state that, when the sampling density is greater than a critical value, geostatistics and deterministic interpolation methods give similar estimations.

Keywords

GEOSTATISTICS INVERSE DISTANCE SQUARES METHOD ORE RESERVES ESTIMATION SAMPLING DENSITY

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