University of Western Australia, SEG Student Chapter

VICTORIAN GOLFIELDS AND SOUTH AUSTRALIA FIELD TRIP REPORT, 2018

The Student Chapter from the University of Western Australia visited two mineral fields within the states of South Australia and Victoria, from the 11th to the 17th of November 2018. The main aim of the field trip was to gain exposure to world class gold and copper-gold-uranium systems in Australia, we had the opportunity to visit the historic Deborah mine and recent Costerfield discovery in the Victorian Goldfields as well as the world class Olympic Dam deposit in the Gawler Craton. In the following we described the activities and itinerary.

Fig. 1 Regional Geology of the Victorian Goldfields (William, 2006) and locations of the Deborah (blue star) and Costerfield (green star) deposits.

Day 1, 11th of November 2018: Flight from Perth to Melbourne and drive to Bendigo, historical mining town. Stayed over at Bendigo.

Day 2, 12th of November 2018: Presentation of the geology of the Victorian Fields (Fig. 1) and exploration strategies was given by geologist Bill Allen, Bendigo Heritage Attraction. Site visit to the Deborah gold mine and museum. The historical Deborah mine is now open to the public for educational visits as well as professional tours for mining engineers and geologists (e.g. Monash University). The original infrastructure is still in place and well maintained, the tours operate by mining engineers and underground geologist. The shafts operate on steam powered engines, from the late XIX century, while load cages and wood frames are placed since the 1950’s. After the mine visit we inspected Victoria Hill and historical landmark for mining, where surface mining took place in the 1870’s by initial German prospectors and Cornish miners.

Fig. 2 A Bendigo Heritage Attraction, Deborah Mine. Field trip participants panning to collect a spec or two of gold. B Underground workings, face showing quartz-carbonate veins hosted in shale and sandstones.

DAY 3, 13th of November 2018: Visit to Costerfield Au-Sb deposit, a presentation on the geological model of the Costerfield deposit and regional geology of the Victorian gold field was given by Chris Davis (Exploration and Resource Manager, Mandalay Resources). An underground visit was given by Kenneth Bush (Project Exploration Geologist, Mandalay Resources), visiting the Brunswick and N-lode orebodies. Mineralization is contained in shear hosted veins crosscutting N-S foliation of sandstones and shales, commonly in fold hinges or along fold limbs (Williams, 2006). The underground visit was followed by core inspection of high-grade intercepts with visible gold and euhedral stibnite specimen hosted in quartz veins.

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Fig. 3 Photos from Costerfield mine. A High-grade Au in stibnite vein (Augusta). B Field trip participants at the Cuffley deposit, Au-Sb hosted in a shear (Brunswick Lode).

DAY 4, 14th of November 2018: Originally a visit to the high-grade Fosterville deposit was scheduled on that day, unfortunately due to technical difficulties in the mine, staff from Kirkland Lake Gold had to cancel the visit. Instead we visited the Melbourne Museum and their mineral collection including high grade gold specimens from the Victorian Gold fields. Pb-Zn-Cu ore specimens from Broken Hill as well as Banded Iron Formation from the Pilbara are in exhibition. Other mineral localities of the collection included the Congo, Namibia and Mexico.

Flight to Adelaide and stay over.

Fig. 4 A SEG-UWA Student Chapter members at the Mineral Collection, Melbourne Museum. B Gold specimens from Bendigo, Victoria Hill, Deborah and Eagle Hawk; Victorian Goldfields.

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DAY 5, 15th of November 2018: Visit to the core library of the Geological Survey of South Australia (2nd Largest in the world). We inspected core from key copper-gold-uranium deposits in the Gawler Craton including Olympic Dam, Carrapateena, Curnamona, Punt Hill, Mount Woods and Intercept Hill. The visit also included a presentation from Anthony Reid (Senior Principal Geoscientist – Geological Survey of South Australia) on recent developments and surveys acquired by the Geological Survey including Magneto Telluric surveys and Sm-Nd surveys on granitic suites in the Gawler Craton. Flight to Roxby Downs and stay over.

Fig. 5 A Students and professional guests at the South Australia Drill Core Reference Library. Left to Right: Joel Blake (RioTinto), Roger Norris (RioTinto), Marcelo Godefroy (UWA), Gonzalo Henriquez (UWA), Eliza Smith (UWA), Lance Glasser (RioTinto), Maelle Palabe (U. Nancy – UWA), Anthony Reid (Geological Survey of South Australia) and Lachlan Hennessy (AngloAm) B Au-Cu-FeO ore of the Curnamona, Province. C Magnetite after hematite blades (Mushketovite), Mount Woods Region.

DAY 6, 16th of November 2018: Site visit to the world class Olympic Dam deposit. The visit included a presentation on the discovery history, exploration, regional setting, ore resources, metallurgy and geology of the Olympic Dam deposit given by Jesse Clark (Senior Geologist –

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BHP Olympic Dam). The presentation was followed by a visit to the discovery site of the discovery drill hole. The site was a farmer’s water supply in the year Melbourne was hosting the Olympic games, thus the Olympic Dam name was born. Inspection of drill core containing high grade copper intercepts hosted in the Roxby Down granite included samples enriched in chalcopyrite, bornite and chalcocite with 5-7 % grade copper. Due to mass production with systematic cave blocking an underground visit was logistically impossible and non-compliant with BHP safety standards.

Fig. 6 Site visit to the Olympic Dam deposit, Roxby Downs, SA. A Commemorative plate dedicated to Roy Woodall and Western Mining Company exploration team, at the discovery site of the Olympic Dam deposit with Jesse Clark (BHP). B Hematite-Chalcopyrite breccia hosted in Roxby Granite. C Roxby granite altered to sericite-chlorite-hematite. D Chalcocite bleb in chalcopyrite-hematite breccia, hosted by Roxby granite.

DAY 7, 17th of November 2018: Flight to Adelaide and return to Perth from Adelaide airport. End of the field trip.

We acknowledge the financial and logistic support of all the involved organizations

PATRONS

SPONSORS

Host companies and organizations Central Debora Gold Mine Bendigo, Costerfield-Mandalay Resources, Drill Core Reference Library -Geological Survey of South Australia and Olympic Dam-BHP Students and Industry field trip participants UWA students: Gonzalo Henriquez, Eliza Smith, Maelle Palabe, Marcelo Godefroy, Rio Tinto: Lance C. Glasser (Project Geoscientist), Roger Grant Norris (Principal Geoscientist) and Joel Blake (Principal Geologist) Anglo American: Jamin Cristall (Principal Geophysicist) and Lachlan Hennessy (Project Geophysicist).