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By Mike Porter
As the Qantas flight from southern Africa descended into Perth on the bright, crisp, winter afternoon of Tuesday 29 th July 1997, it brought to a close the second of this years Australian Mineral Foundation International Study Tours - Geology and Ore Deposits.
This tour, "Archaean Gold and Related Ore Deposits", had commenced three weeks earlier when the bulk of the party left Australia for Canada. The Australians that took the full tour, had travelled 53 000 km, right around the world. En-route they had visited fifteen of the worlds classic Archaean gold and related base metal deposits. In addition they had taken part in six comprehensive field reconnaissances, two major seminars and one high level briefing session. The initial ten participants had assembled to start the tour in Edmonton, Canada, on Saturday 5 th July, after travelling from various points around the world. The home coming to Perth brought a sense of professional fulfilment that so much had been heard, seen and absorbed over those weeks; regret that the excitement and mateships enjoyed during the tour must to come to an end. But the home-coming was also tinged by relief that now there was the chance of a rest from the hectic, packed, non-stop, long days and nights of the last three weeks. A senior manager on that flight, involved in gold exploration for one of Australia's largest mining companies, had commented that the tour "was worth every cent his employer had paid". A week earlier another participant, a senior project manager from a major South African mining house, remarked that he had "... seen so much new that it had expanded his horizons and allowed him the opportunity to think more laterally". Others were clearly stimulated by the interaction with their fellow participants on tour, and with those they had learned from at the mines, field reconnaissances and seminars. The mines covered most of the significant styles of gold deposit known within the Archaean. They had been in diverse and exotic locations, ranging from the Arctic tundra of Canada's North West Territories, to tropical Africa in the Limpopo Mobile Belt of Zimbabwe. The mines varied from large open cuts, to extensive narrow stopes 2.5 km below surface. Some of the participants had only taken the 14 day North American Module, while others joined the main party in Johannesburg on Sunday 20 th July for the 8 day African Module. A core group took the full tour, travelling from Canada to Africa via London. A number stayed on in Africa at the end to visit other mines. The participants were from several centres in Australia representing the country's more progressive and successful gold producers and explorers, while others were from major companies in Africa. The aim of the tour was to see as comprehensive and diverse a set of Archaean gold deposits as practical, as well as understanding their regional geological and metallogenic setting. While the principal focus of the tour was geology and mineralisation, provision was made to allow the participants to be expertly briefed on as much detail as they required of the mining, metallurgical and commercial aspects of each operation. The Ore Deposits The tour started in the Slave Province of northern Canada, with a charter flight north to the Lupin mine on the Arctic Circle, followed by the Miramar Con and Giant gold mines at Yellowknife. Then on to the Superior Province in Ontario, starting in the west with the Campbell Mine at Red Lake, before continuing south to the Hemlo district where both the David Bell and Golden Giant mines were visited. The nearby, now exhausted, Manitouwadge Cu-Zn massive sulphide deposits were also included. This was followed by the Dome lode gold and Kidd Creek Cu-Zn mines to the east near Timmins, now in the Abitibi Belt and finally the Laronde and Bousquet #2 gold mines in the Rouyn-Cadillac district in Quebec, also in the Abitibi Belt. These latter deposits are massive sulphide gold orebodies with accompanying major base metal lenses. In Africa, the tour continued with the East Driefontein and Loraine Witwatersrand gold mines, some 300 km apart. This was followed by a core and briefing session on the vast new Avgold Target Project, with bulked Witwatersrand intersections of up to 128.6 m @ 6.42 g/t Au, containing an indicated resource of 1800 t Au (57.4 Moz). The tour then moved east to the greenstone Eastern Transvaal Consolidated gold mines in the Barberton Mountains before proceeding to Zimbabwe and the Renco granulite hosted orebody. Each mine visit comprised a briefing and discussion session, an underground and/or open pit tour to inspect the hosts rocks and ore, with experienced mine geologists giving explanations and answering questions. In addition, or alternatively, as in the Target case, there were core inspections at surface. Field Reconnaissance and Core In each of the districts or 'camps' in Canada, there was also a separate field reconnaissance of the regional geology and metallogenic setting conducted by local experts from Provincial geological surveys or from industry. These put the deposits visited into a geological perspective and showed how the mineralisation was reflected at surface. In Africa a comprehensive core display of the sequence through the Witwatersrand Basin and each of the main reefs was undertaken at the Gold Fields Geological Centre, presented by that company's senior exploration geologists. A field inspection of deep drilling and seismic surveys at the Target Project was also conducted. Seminars and Briefings Two major seminars were run, one at Timmins in Canada, the other in Johannesburg. The Timmins seminar was presented by international and local experts from government and industry. It covered the distribution of Archaean and related base metals across the Canadian Shield, the Superior Province the Abitibi Belt and the Timmins-Porcupine camp. The Johannesburg seminar was held in association with the Geological Survey of South Africa and included presentations on African geology and metallogeny as well as papers on West African, East African and South African gold deposits. Over 120 South African geologists attended, also hearing presentations by AMF Tour Participants on Australian gold deposits. Both seminars included sessions on the commercial, regulatory, social and political environment of exploration and mining in the country/region. In Zimbabwe, the Zimbabwe Geological Survey conducted a superb briefing on the geology and gold deposits of the country. Participants also gave talks at well attended industry association meetings, such as the CIM in Yellowknife, allowing them the opportunity to make further contacts. Organisation All of the planning, costing and tedious organisational detail of the tour were carried out by the AMF. All the participants had to do was get to the starting point with their field and travel gear, and a credit card, and to read the preparatory literature assembled by the AMF. This literature had been delivered before hand, along with a travel pack which included a sturdy haversack, note books, air tickets, the detailed itinerary, a geological summary, and other useful items. This preparation by the AMF permitted costs to be kept to a minimum, while removing all of the hassle and allowing the participants to focus on the main goal - Archaean gold. | |||||||||||
