Stawell is on the boundary between two ancient geological belts which contain one of the most complex gold deposits in Australia. The key focus of the exploration program was to find where to drill to hit gold lodes thought to lie beyond a formation known as the South Fault, located below the existing mine. The lodes had eluded past drilling attempts. Dr Miller spent more than eight months mapping underground. The existing mine goes down 750 metres and has more than 50 kilometres of underground roads.
Geological mapping has to be done between trucking schedules and underground blasting times.
Mapping 600 metres underground with a head torch in hot and humid conditions is a far different experience to mapping at ground level. Detailed structural analysis by Dr Miller revealed the South Fault had a complex movement history. His analysis indicated the offset of the gold lodes was at depth and to the north of the existing mine. Senior Geologist of Stawell Gold Mines parent company, Mining Project Investors, University of Melbourne graduate Mr John Dugdale, combined the new data on the South Fault with existing data and used magnetic modelling of potential targets to design a drilling program that subsequently showed Dr Miller was right on target.