Ahead of a planned underground drilling programme, surface drilling within 200m of the Castle Silver mine adit has intersected 0.65m at 1.55% Co, 0.65% Ni, 0.61g/t Au and 8.8g/t Ag from 3.85m.

The mine historically produced at least 9.4 million ounces of silver and 376,053 pounds of cobalt between 1917-1989. It also had further undocumented production.

"Once again we've demonstrated how historical operators overlooked the potential for cobalt, gold and base metals at the Castle mine as they focused exclusively on the extraction of high-grade silver," CEO and president Frank Basa said.

The company said it was employing "a century-old approach" to resource development and mining whereby it drilled for structure and mined for grade.

Basa recently told Mining Journal of experiencing the real demand for cobalt, saying people had already asked when he was going to start mining.

The company has studies underway to develop a milling processing facility and leach plant on one of its properties and has also developed the Re-2OX cobalt processing technology that has been pilot plant-tested to produce cobalt salt powders for the battery sector.