Dias Geophysical successfully imaged geological structure, lithology and mineralization at the Weednanna Gold Deposit in South Australia. A rolling 3D DIAS32 survey images the sulphide mineralization beneath ubiquitous surficial sediments with great clarity and to a depth of over 300 m. The survey generated several high priority targets.
The Weednanna deposit is a magnetite breccia in carbonate altered rocks forming a skarn near the contact with a granite intrusion and containing elevated gold, bismuth, tin, uranium, lead and zinc. High grade gold is associated with sulphide replacement of magnetite. The survey area is covered by a veneer of transported sediments that makes exploration challenging. Prior to the DIAS32 survey, little was known about the potential mineralization below 200 m. The strong association of gold with sulphides makes the IP method an effective tool for imaging potential mineralization.
A rolling 3D survey with CVR was completed over the 1.1 km X 1.5 km survey area with the DIAS32 system. A line spacing of 50 m and a receiver spacing of 25 m provided detailed 3D imaging of the subsurface. The CVR data set provided multi-scale and multi-azimuth data for 3D inversion. The final 3D models of resistivity and chargeability were resolved to 5 m.
The DIAS32 3D survey successfully imaged the mineralized system to a depth of approximately 300 m. The final 3D models of resistivity and chargeability provided insight into structure, lithology and mineralization, and several high priority targets were interpreted from integration of the survey results with other geophysical and geological data sets.
- High-grade, intrusion-related gold (skarn)
- Imaged sulphides associated with gold mineralization to a depth of 300 m
- Identified several high priority targets for further exploration