In the Leonora region, exploration is focused on defining additional ore sources to supplement production from Gwalia.
The Gwalia deposit has produced over 5 million ounces over a long history dating back to 1897. Mineralisation is hosted within an east-dipping series of basalts and dolerites. Multiple strongly mineralised en-echelon lodes are present which trend NNE over a strike length of 500m, and maintain strong down-plunge continuity.
Resource definition drilling by St Barbara leading up to development was focused on the South Gwalia Series and South-West Branch lodes, which host the bulk of the reserves. Positions such as the Main Lode, Hangingwall Lode, and West Lode represent extensional targets immediately along strike from existing resource. The ore body also remains open at depth.
Targets in the Leonora District continue to be prioritised through analysis of the structural geology coupled with detailed mapping of alteration systems. Programs are currently focussed on improving the chances of exploration success by developing a detailed understanding of the target analogues and gaining maximum value from previous exploration data, which includes extensive geophysical and geochemical surveys, and a large amount of historical drilling. Focus will be upon targets that are either under younger cover or where there has been minimal exploration at depth.