Resource Estimation and Three-Dimensional Modelling of Gold Mineralisation at Mt Leyshon Gold Mine, NE Queensland

Geostatistical analysis, resource estimation and three-dimensional modelling of the gold grade distribution was undertaken using exploration drillhole data taken from the Mt Leyshon gold mine. The main aims of the project were to provide an independent estimate of the primary gold resource and to improve the estimate by better understanding the statistical distribution of gold and the establishment of more robust variograms. These criteria have been achieved by the removal of low grade sub-populations, increased sample size and access to data from the most recent drilling program. The outcome of this statistical study has led to a lowering of the sill and nugget variance of the variograms used. Distinct geometric anisotropy was identified in all the resource estimation zones and was used to model gold grade distribution.Two independent resource estimates were established from the primary gold resource, one based on a geostatistical estimator (kriging) and the other on a traditional estimator (inverse distance weighting). Both methods were compared with a contemporary kriged estimate by Mt Leyshon Gold Mines Ltd.