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The use is described of implicit modelling, based on recent advances in fast scattered data interpolation methods. A continuous three-dimensional function is defined that describes the grade or rock distribution. This volumetric function is interrogated for a grade value or a geological surface, thus allowing the extraction of the 3D object to be automated and eliminating the need to digitise surfaces manually. Since the function is continuous throughout space and does not depend on a mesh or grid for its definition, the extracted geological ore grade wireframes can be constructed at any desired resolution in the specific volume of interest. The volume modelling method can work on scattered drillhole data of any data density, including processing combined information from dense grade control data as well as sparse resource drilling. Advantages over surface modelling include the ability to wireframe geological objects quickly; substantial improvement in modelling accuracy and the ability to generate conditional models rapidly allowing mining risks inherent in geological modelling to be examined., The use is described of implicit modelling, based on recent advances in fast scattered data interpolation methods. A continuous three-dimensional function is defined that describes the grade or rock distribution. This volumetric function is interrogated for a grade value or a geological surface, thus allowing the extraction of the 3D object to be automated and eliminating the need to digitise surfaces manually. Since the function is continuous throughout space and does not depend on a mesh or grid for its definition, the extracted geological ore grade wireframes can be constructed at any desired resolution in the specific volume of interest. The volume modelling method can work on scattered drillhole data of any data density, including processing combined information from dense grade control data as well as sparse resource drilling. Advantages over surface modelling include the ability to wireframe geological objects quickly; substantial improvement in modelling accuracy and the ability to generate conditional models rapidly allowing mining risks inherent in geological modelling to be examined.

A modelling technique is described which combines Au grade and alteration. The method was applied to the Wallaby deposit in Western Australia to obtain a greater level of detail to the grade estimation in a region tested by relatively sparse drilling. This was achieved by using the correlation of Au grade and alteration, along with the spatial characteristics of the alteration, when estimating grades within a number of lodes. The alteration-driven estimation was used in conjunction with an unfolding approach, together with probability estimates, to overcome geometric data constraints. The technique allows greater control and probably provides a more reliable estimate of the mineable resources than a global grade cut-off when visual control is to be a major vector in grade control., A modelling technique is described which combines Au grade and alteration. The method was applied to the Wallaby deposit in Western Australia to obtain a greater level of detail to the grade estimation in a region tested by relatively sparse drilling. This was achieved by using the correlation of Au grade and alteration, along with the spatial characteristics of the alteration, when estimating grades within a number of lodes. The alteration-driven estimation was used in conjunction with an unfolding approach, together with probability estimates, to overcome geometric data constraints. The technique allows greater control and probably provides a more reliable estimate of the mineable resources than a global grade cut-off when visual control is to be a major vector in grade control.

Conditional simulation was used to derive a number of gold estimation scenarios within a typical volume of the Western Australian deposit. These scenarios were interrogated for a selection of bench heights and ore block dimensions. The results were reported as a range of grade-tonnage relationships and compared with the kriged resource model, allowing the it to be calibrated to a specific bench height and ore block size. More realistic dilution and ore-loss values for a number of bench heights were then calculated from the resource model. These values were used to determine the economic sensitivity of particular mining methods. The spread of results also provided an indication of confidence in the kriged grade estimate for different zones of mineralisation., Conditional simulation was used to derive a number of gold estimation scenarios within a typical volume of the Western Australian deposit. These scenarios were interrogated for a selection of bench heights and ore block dimensions. The results were reported as a range of grade-tonnage relationships and compared with the kriged resource model, allowing the it to be calibrated to a specific bench height and ore block size. More realistic dilution and ore-loss values for a number of bench heights were then calculated from the resource model. These values were used to determine the economic sensitivity of particular mining methods. The spread of results also provided an indication of confidence in the kriged grade estimate for different zones of mineralisation.