Sabre is the rebadged Arizona Gold, which changed name earlier this month after its merger with Golden Predator and its near-term Brewery Creek gold project in Canada's Yukon.

Sabre said Copperstone's measured and indicated resource was now 1.3 million tonnes grading 7.3g/t for 306,000oz and the inferred component stood at 1.1Mt at 5.9g/t for 212,000oz.

"We are pleased to release an updated mineral resource estimate for the Copperstone gold mine which has increased by 23% in all categories at an average grade of 6.6g/t gold and 53% increase in the measured category at 7.6g/t gold from the previously published resource estimate," president and CEO Giulio Bonifacio said.

"Additionally, several highly prospective expansion targets that have been recently identified remain untested."

Copperstone is a fully-permitted project which previously produced about 500,000oz of gold between 1987-1993 from an openpit, Sabre said.

It's planning an underground operation and said this month final mine design and schedules were underway.

The project has 4.3km of underground access and two portals, along with existing underground electrical, ventilation and water management, Sabre said.

The company had C$19 million in cash and short term investments at July 31.

Eric Sprott is one of its prominent investors, according to a presentation this month.

Sabre closed unchanged at 10c yesterday, valuing it at $34.6 million (US$27 million).