Geologists study ancient Bourke Rocks for new mineral deposits

A large team of geoscientists and technical assistants using state-of-the-art equipment have recently completed a deep seismic survey designed to unlock new discoveries of potential mineral deposits near Bourke in the State’s far northwest.

“This is the latest example of Exploration NSW at work – a seven-year, $30 million project designed to accelerate mineral and petroleum exploration and investment in the State,” said Lindsay Gilligan, Director Geological Survey NSW.

The State Government has contributed $500,000 to a cutting-edge geophysical survey.

“During the three-week survey, the team acquired data on a large belt of deformed rocks created hundreds of millions of years ago and only very poorly exposed at the surface.

The survey looked at rocks 30 to 60 kms below the surface.

“Seismic measurements were taken by three vibroseis trucks, which are large hydraulic vibrating machines mounted on buggies about the size of a standard drilling rig.

“The technique sends sound waves into the ground and then captures them as they bounce back, allowing the geoscientists to capture images of the earth's crust.

“With these images, we hope to more precisely locate the position of the deformed belt of rocks and predict the likely ore deposits that might exist within them.

The survey will give information on the rocks and structures in the area, which is thought to have potential for gold, copper, base metals and petroleum.

“Processing all the data will take several months and results are not expected until early 2006.

While the survey will not directly unlock the potential mineral wealth it will give information which should help geoscientists understand it. Should follow-up studies and subsequent exploration be successful, then the area would constitute a new mineral province in NSW.

Mr Gilligan said the survey could also have the added benefit of helping scientists better understand the petroleum systems within the Darling Basin.

 “The seismic survey will ultimately lead to a more complete picture of the 3D geometry of the earth within the region,” he said.

“Once the third dimension of the geology is understood, it is easier to determine if basin structures are available and if those structures provide favourable traps for oil or gas.”

This seismic survey is a joint project between the NSW Department of Primary Industries and the Cooperative Research Centre for Predictive Mineral Discovery. The NSW DPI is contributing $500,000 of the total $700,000 cost of the project, through Exploration NSW.

Work of the NSW Geological Survey has been the springboard for a renewed interest in the mineral prospectivity of the Bourke area. A number of small junior companies and at least one major have established substantial holdings in the area for exploration.

The Bourke region has produced gold, copper and base metals from historic mines however, modern exploration in the area is made difficult by the variable thickness of younger rock cover.