Norseman Gold operates Australia's longest continuously running gold mining operation, having produced over 5.5 million ounces of gold over a period of more than 65 years from its Norseman field located 725km east of Perth, Western Australia.
The Scotia, Ajax, Esperanto, Harlequin South and Railway deposits comprise the non Main Fields and Harlequin underground resource inventory. Of these the Scotia deposit is considered the most important.
Scotia is located approximately 30 km south of the Norseman township and consists of irregular, east dipping vein sets. The mineralised en-echelon veins are localised within a 30m shear zone with ore shoots plunging 20° towards the northeast.
The Scotia deposit was mined periodically by open cut and underground methods from the late 1980’s. The resource to mill reconciliation for the open pits was not good, principally due to the complexity of the ore zone geometry. Extreme short scale variability was noted in the ore zones with the strike length, thickness and attitude of the zones all highly variable.
Little detail is available on the approach and parameters used to construct the underground resource at Scotia, although a pseudo polygonal approach appears to have been implemented which, given the mineralisation style, is considered inappropriate at Scotia.