The Long Island study is considering a large cutback mined as a starter pit then strip-mined, similar to the processes used in open pit coal mining.

But the plan is contingent on further exploration confirming extensions of the orebody.

So far, 55,000m of drilling completed since June has returned promising results with similar grade and continuity as the current resource.

At Havana South, drilling identified a new high-grade plunging shoot, with results including 39m at 1.89 grams per tonne gold from 405m, including 12m at 3.54gpt gold; and 19m at 3.76gpt from 374m, including 10m at 6.4gpt and 5m at 5.35gpt.

Initial results suggest the potential for at least another two high-grade shoots with drilling hitting 7m at 3.64gpt gold from 345m, including 5m at 4.08gpt and 9m at 3.29gpt; 12m at 2.35gpt gold from 396m, including 7m at 3.6gpt; and 9m at 9.32gpt gold from 212m, including 4m at 20.4gpt gold.

Drilling at the Swizzler prospect, designed to test for the potential to link the existing Tropicana and Havana pits, also returned positive results.

Highlights from drilling at Swizzler included 17m at 4.29gpt gold from 281m, including 6m at 10.6gpt; 7m at 3.73gpt gold from 384m, including 6m at 4.26gpt gold; and 10m at 2.86gpt gold from 415m, including 8m at 3.16gpt.

Results from the Tropicana pit – which included 16.5m at 5.69gpt gold from 345.5m, including 6m at 14.4gpt – confirmed earlier results and extended mineralisation.

An update to the resource estimate is due by the end of June.

IGO managing director Peter Bradford said the partners were committed to unlocking potential at Tropicana and extending the seven-year mine life.

“The drilling results received to date continue to confirm both the strike and depth extensions of the mineralisation,” he said.

“The drilling has linked mineralisation from Havana South in the south through to Tropicana in the north, a strike length of over 4.7km.”

There is around 4 million ounces of resource outside the current mine life.

The drilling, which will extend the resource base, coupled with the Long Island study, has the potential to drive a step-change to the magnitude of the Tropicana resource base, cementing Tropicana as a truly world-class gold operation,” Bradford said.

Tropicana just edged out Telfer as Australia’s fourth-largest gold mine by production in 2015, delivering 488,939 ounces of gold.

The operation is 70% owned and operated by AngloGold with IGO as the minority partner.

AngloGold shares, which are thinly traded in Australia, rose 3% to $A3.45, while IGO shares gained 2.4% to $2.57.