One of the industry’s best known geologists on placer mineral deposits believes there is ample potential for more alluvial gold mining operations in the Otago-Southland region.
John Youngson of Youngson Geoscience told NZResources that many of the deposits in southern Otago and in Southland had been swampy areas in need of drainage.
This had happened in part due to alluvial gold mining dredges and also farm dams. There was now more accessible ground.
In his presentation to the AusIMM NZ Mining Conference in Christchurch, Youngson detailed target areas for placer gold sampling and then detailed areas where gold particles also contained mercury and zones where the samples did not contain mercury.
He concluded that primary gold in Caples Terrane and placer gold on it was dominated by gold-silver-mercury alloy, whereas primary gold with significant mercury in the Rakaia Terrane was restricted to specific zones.
Placer gold in eastern Southland was generally mercury-poor and were mostly derived from primary and palaeo-placer sources in the Rakaia Terrane.