Oceana Gold's exploration at the historic underground Blackwater gold mine near Reefton on the West Coast has returned very high gold grades from the last phase of its deep-drilling programme.
Eight test holes around the Birthday Reef were completed and with the latest positive gold grades, Oceana will begin a pre-feasibility study on the Blackwater project, to be completed before the end of the year.
The two most recent test holes were about 250m below the bottom of the lowest mined level of the Blackwater mine, which got to about 1000m deep. The estimated gold resource of the Birthday Reef was subsequently upgraded by Oceana from 350,000 ounces to 600,000 ounces at 21g of gold yielded per tonne of ore (g/t). Oceana's new study is targeting an annual production rate of 50,000 ounces to 60,000 ounces.
The Blackwater underground mine, which was opened in 1906, went on to become Reefton's largest gold yielder, producing 740,000 ounces from 1.6 million tonnes of ore at a remarkable 14.6g/t, before its closure in 1951 after a shaft collapse.
Historically, each vertical metre of the Birthday Reef in the Blackwater mine yielded 1000 ounces of gold. Blackwater totalled about a third of the 2 million ounces of hard-rock gold extracted from the region.
Oceana chief executive, Mick Wilkes, said he was ''very pleased'' with the continued success of the Blackwater drilling programme.
''To date, we have uncovered remarkable continuity in the Birthday Reef which gives us strong confidence of the continuation of the ore body below previously mined workings and ability to announce the updated Blackwater resources,'' he said.
Individual intersections during test drilling of the Birthday Reef returned 450mm at 31.80g/t, 410mm at 62.40g/t and in an adjacent hole, had 710mm at 134g/t and 450mm at 61.9g/t.
By comparison, estimated gold resources last December for Oceana at Macraes, its combined open pit and underground operations, averaged 1.38g/t and Reefton's open pit operations were 1.90g/t.
