The Golden Mile, which has been mined continuously for the past 100
years by both underground and more recently open pit methods, occupies
an area of 1.2 km by 4 km adjacent to the city of Kalgoorlie Boulder in
Western Australia (Figure 1). Large-scale open pit mining at the Kalgoorlie Consolidated Gold
Mines (KCGM) Fimiston operations is currently extracting 7.8 million
tonnes of oxide and sulphide ore for a total production of 522 000 oz per
annum. The effectiveness of grade estimation techniques at KCGM has been
examined with reference to existing 10 m bench sample data from all
operating areas within the Eastern Lode System of the Main and North
pits. The aim of the study was to recommend practical parameters for
grade control estimation. The review included comprehensive variography and comparison of
nonparametric estimation methods (Joumel, 1983) such as indicator
kriging and probability kriging with ordinary kriging, leading to the
development of improved grade control parameters and procedures for
both daily quality control and short term mine planning. This paper reviews the geological, statistical, geostatistical, mining and
modelling features studied in order to present KCGM's Mining
Department with recommendations for improving grade control.