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Bendigo looks to old richer gold workings in its recovery process
After its problems of last year, Bendigo Mining is taking a new approach to exploration by concentrating on extensions to the older higher grade parts of the mining complex.
Author: Ross Louthean
Posted: Tuesday , 22 May 2007
PERTH -
A new exploration approach and a first-time opportunity to test some of the richest parts of the gold mine running beneath the historic Bendigo field in Victoria should turn around its fortunes.
This was the view of Bendigo Mining Ltd's managing director Rod Hanson in an address today to Paydirt's Gold Conference in Perth.
Hanson said the company had learned its lessons from late last year of not managing well, its geological risk for the field. That proved a headline issue that ripped millions of dollars of the company's share market capitalisation, brought about sweeping management changes (including promoting Hanson to head the company) and even raised questions about other companies operating in Victoria.
Today Hanson said a dramatically different approach has been taken to meet challenges of charting a new mining and exploration course along the 10 kilometre long, three kilometre wide Bendigo field which has so far produced 22 million ounces of gold.
This includes a focus on defined stratigraphic or rock units rather than theoretical geological and mineralised ribbons. This, he said was "improving our understanding of where to drill."
"We have moved away from the Deborah and Sheepshead lines and have elected to explore beneath the historically richer hot spots on Garden Gully and New Chum, which are the source of some 70% of the field's historic gold production (Sheepshead and Deborah were readily accessed from the company's Swan decline mine on the outskirts of the city, whereas New Chum for instance is in the heart of modern Bendigo city).
"These higher grade, more productive lines have greater potential to host economic zones of mineralisation than some of the lesser zones subject to the geological risk issues of last year.
"Results to date from the southern Garden Gully zone are consistent with historic workings above the current drill targets and the mineralisation is much stronger than anything encountered at Sheepshead and Deborah.
"The major change in exploration focus on the field has been supported by a significant amount of completed mine development and this provides locations for Garden Gully and New Chum to be tested from underground."
Hanson said the new approach would increase discovery rates for new gold reefs as laminated quartz veins and anticline axes could be intersected in the stratigraphic units.
"The recent Grenfell Reef for example was identified by just three drill holes, meaning less drill metres to define targets and lower discovery costs," he said.
"The approach also allows our extensive knowledge of the field to be better applied to determining reef shapes, range, types and variability."
Bendigo Mining has a $A10 million ($US8.3 M) exploration budget for the field and has assigned four underground drill rigs to generate more than 50,000 metres of new drill core as it looks to lift discovery and development and production options.