De Grey Mining has solidified its fancied Mallina gold project in Western Australia, with an extra 2.1 million ounces (Moz) set to be produced across the life of mine.
The just-released Mallina pre-feasibility study demonstrates the potential for 6.4Moz of gold to be produced across a 13.6-year mine life. A 2021 Mallina scoping study indicated a 4.3Moz production profile across the life of mine.
This equates to an average annual gold production of 540,000oz across the first 10 years of the mine’s life.
Mallina includes the Hemi deposit and other regional deposits, with Hemi to be the flagship mine. Hemi alone has the potential to contribute an average annual gold production of 500,000oz over the first 10 years of the mine’s life.
De Grey said Hemi will be a top-five Australian gold mine when in production, while the deposit is in the top-three undeveloped gold projects worldwide based on average annual gold production rates.
De Grey managing director and chief executive officer Glenn Jardine said the company had been targeting material improvements in several areas since the 2021 scoping study, including annual production rates, grade and mine life.
“Total production has increased by nearly 50 per cent from the scoping study,” he said.
“The increased production has been achieved at increased levels of JORC* measured and indicated resources within the production profile averaging close to 90 per cent over the first 10 years of production compared with 70 per cent in the scoping study.”
De Grey has also announced Hemi’s maiden JORC probable reserve of 5.1Moz at 1.5 grams per tonne (g/t) gold, which it said was one of the largest and highest-grade maiden reserves in recent decades.
“The maiden Hemi reserve leverages off the Hemi mineral resource update announced in May this year of 8.5Moz at 1.2g/t gold of which 5.8Moz at 1.3g/t Au are of JORC indicated classification,” Jardine said.
“This represents an impressive increase in indicated resources at Hemi of 3Moz over the maiden resource announced in 2021.”
De Grey will now progress to a definitive feasibility study (DFS) for Mallina, which it said was expected to be completed in mid-2023.
*JORC stands for the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves.