PERTH (miningweekly.com) – Copper miner Sandfire Resources has added some 64 000 t of copper and 93 000 oz of gold to the resource base at its DeGrussa mine, in Western Australia.

The project’s mineral resource has now increased to some 13.8-million tons, grading 4.8% copper and 1.8 g/t gold for 664 000 t of contained copper and 777 000 oz of contained gold.

The miner said on Thursday that the majority of the increase in tonnage and contained metal came from successful surface drilling programmes at DeGrussa, targeting the two deepest high-grade deposits, Conducter 4 and 5.

The updated resource also reflected the addition of some 8 000 t of contained copper and 30 000 oz of gold from Conductor 1, reflecting an increased understanding of the orebodies, the company said.

MD Karl Simich told shareholders that the increase in the high-grade underground mineral resource inventory was a significant achievement for the company.

“We have been able to more than replace production depletion to December last year, adding 64 000 t of contained copper metal to our high-grade underground mineral resource inventory through our work at Conducter 4 and 5, and in-mine work.”

Simich said that the increased resource would add around one-year’s copper and gold metal to the mine plan.

“To put this in context, the majority of this increase has come through just five strategically targeted deep diamond drill holes, representing an outstanding return for shareholders.”

He noted that the drilling marked the beginning of a new phase of exploration for DeGrussa, during which Sandfire would systematically target near-mine extensions of the deeper deposits, including positions where isolated high-grade intercepts were returned during the discovery days, and which required follow-up.

“Having demonstrated what can be achieved with drilling from surface, we will establish underground drill platforms from later this year to enable us to target further prospective areas,” Simich said.