The director of Geological Survey, NSW, Lindsay Gilligan, says exploration companies often start picking over old workings, such as those at Majors Creek.
The geoscience agency provides information and advice to government and the exploration and mining industries.
Mr Gilligan said Dargues Reef part of Cortona Resources' Majors Creek Gold Project was well known as an old historical deposit, but in recent times Moly Mines (which later sold its gold assets to Cortona Resources) rediscovered high-grade intersections at the site, working from the agency's digital imaging geological system.
''That's why we require companies to report their exploration activities and that's the advantage over other jurisdictions we have this obligation on companies to report exploration. When a company moves on or a title lapses, that exploration information goes into the public domain.''
Exploration in Australia hasn't stopped since gold was first discovered at Ophir, near Orange, in 1851. Captains Flat, east of Queanbeyan, continues to attract mining interest, while Canberra-based Capital Mining is proposing an open-cut operation at Chakola, 15km north of Cooma. Tri-Origin has been looking at the feasibility of restarting mining at Woodlawn, near Tarago, but work is on hold.
Several mining companies have poked into workings at Majors Creek, where operations have stopped as suddenly as they have started.
Mr Gilligan said a lot of gold had been produced in southern NSW, including alluvial gold at Majors Creek.
Today mining and extraction technology could work with much lower grades than in earlier times.
''These days with large operations, they can work down to 112 to 2g of gold. There has always been fairly healthy gold exploration. The gloss was taken off it with the global financial crisis but exploration is coming back quite a bit.
''The price has gone up and it's fair to say confidence has come back to the industry fairly substantially too.''
The more uncertain the economic climate the more gold was a currency of last resort.
While much had been done to lessen mining impacts on the environment, there was a strict approval process through local government bodies and NSW's Department of Planning.
Cortona Resources geologist Jon Hoye said Dargues Reef was small compared with the giant Cadia mine near Orange.
Over 10 years what came out of Dargues Reef would come out of Cadia in a month, because of the differences in ore grade.
The underground operation would not use ''rip, tear and shred'' methods previously associated with mining. He could not comment on truck movements, but said it was likely there would be no more than one a day out of the site, and trucks would leave without having to cross the historical bridge into Majors Creek. Cortona's NSW exploration manager, Greg Cozens, said 50 per cent of the gold would be recovered on site on a gravity circuit system and riffle table.
A pyrite concentrate containing the remaining gold would be processed off-site, at a place yet to be determined.
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