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Symposium highlights gold potential

Symposium highlights gold potential
Examining gold-silver bearing quartz veins in quartz-adularia altered ignimbrite exposed in the Ohakuri dam abutments.

The Gold 17 international symposium held in Rotorua in February helped to showcase to the international community the potential for gold exploration in New Zealand, says Tony Christie who assisted the convenor of the conference, Julian Vearncombe of SJS Resource Management and Geosymposia.

“New Zealand has good exploration potential and we hope that some of the overseas companies who attended will be encouraged to come here to explore in the future,” says Christie.

It is the first time that the Australian Institute of Geoscientists gold symposium has been held in New Zealand and around 100 delegates attended, predominantly from Australia and New Zealand, but also from as far away as Mongolia, Uruguay, Canada, US and Europe.

The decision to focus the conference solely on gold reflected the importance of the mineral to the New Zealand industry, says Christie.

“It’s an exciting time for exploration in New Zealand, with OceanaGold engaged in major drilling programmes at Waihi and Macraes, and both mining areas continuing to produce gold.

“They are world class deposits and exploration has been successful finding new resources to keep them going.”

The conference technical programme was a single stream of presentations with seven one-hour keynote presentations interspersed with twenty seven 30-minute presentations.

Christie says that the format worked well and ensured good attendance for the presenters and lots of questions from the floor.

A range of experts from New Zealand and offshore gave insightful keynote presentations.

New Zealand speakers included Shaun Barker from the University of Waikato who spoke on alteration and geochemical signatures of low-sulfidation epithermal veins; Julie Rowland, from the University of Auckland, who gave a presentation on the influence of inherited structure on localisation of epithermal gold mineralisation, and Dave Craw, from the University of Otago who spoke on fluids and orogenic gold in the South Island.

Symposium highlights gold potential

Noel Becker explaining the Waikaia placer gold mining operation near Freshford, Southland on the Gold
17 preconference Otago field trip.

Symposium highlights gold potential

Tour leader Dave Craw from the University of Otago demonstrating the presence of gold in the gravels
at St Bathans.

From overseas, John Thompson, from Cornell University in the USA, spoke on hydrothermal alteration in gold systems; David Cooke, from the University of Tasmania, presented on epithermal gold deposits of the circum-Pacific and Stuart Simmons from the University of Utah gave a talk on spatial and temporal variations in epithermal ore-forming processes.

Overseas deposits described by overseas presenters included the Minto copper-gold mine and vein deposits (Klondike in the Yukon, Canada), Ann Mason copper-gold-molybdenum deposit (Nevada), Greens Creek gold-bearing volcanogenic massive sulphide deposit (Alaska), Mt Wright intrusion-related gold deposit (North Queensland), Tunkilla gold deposit (South Australia), gold and gold-copper deposits of southern Peru and silver-gold veins of Mexico.

Christie says it was critical for the industry to have access to the latest research and exploration updates.

Opportunities for delegates to network was another important aspect of the conference.

“Getting people together provides great stimulation and generates new ideas and ways of looking at things.

“Feedback has been very positive.” Delegates also enjoyed the opportunity to explore first hand OceanaGold’s Macraes and Waihi operations on field trips held before and after the conference.

The symposium venue in the hydrothermally active city of Rotorua and a field trip to the gold-rich Coromandel, allowed delegates to see first hand modern environments in which epithermal gold deposits are formed.

The four-day epithermal field trip on Coromandel and TVZ epithermal/geothermal gold had 14 participants, all from overseas, and involved visiting Orakeikorako, Waiotapu and Waimangu thermal parks.

“These geothermal systems show gold mineralisation processes in action which assists gold exploration.

“You can read all you like in books and journals but you also need to see the rocks – especially the spatial relationships, and the extent and style of mineralisation.

“It was really good to see things in the flesh,” says Christie. At Waihi, the group was shown new discoveries of sinter in drill core from the Favona vein system.

“This sinter discovery is very significant for reconstructing the hydrothermal system architecture and can be used to model nearby deposits for exploration.”

OceanaGold is continuing an aggressive exploration drilling campaign at Waihi started by the previous owners Newmont Waihi Gold in order to find new gold resources and extend the life of the mine beyond known reserves of two years.

Several new blocks of gold ore have been found in and adjacent to known veins and so the future is looking good if resource consents to mine can be obtained.

“Gold features highly in New Zealand mineral production and we’ve had fantastic success in exploration around the operating mines.

“There is significant potential elsewhere in New Zealand as well and we’ve got several companies exploring in New Zealand at the moment.”