PERTH (miningweekly.com) – Gold producer Lihir on Monday downgraded its reserve estimate at the Bonikro operation, in the Cote d’Ivoire.

The total ore reserves have now been estimated at 760 000 oz of gold, compared with the previous reserve estimate of 930 000 oz of gold. The company said in a statement on Monday that the movement in reserves was owing to mining depletion of around 275 000 oz.

The reserve estimate was also impacted on by an increase in the gold price assumption, changes to the resources model, pit preoptimisation, changes to the cost assumption and a reduction in the cut-off grade from 0,6 g/t to 0,5 g/t.

The mineral resources at Bonikro have also been updated to 1,2-million ounces, compared with the 1,3-million ounces previously identified, which has since been depleted by mining.

Lihir said that the latest reserve estimate did not account for drilling since November last year, and did not include any estimates related to the nearby Hiré district.

Drilling results from that campaign would be included in the next estimation, which is expected later this year, and would coincide with the upgrade of the Hiré resources and reserves, as part of the Bonikro expansion feasibility study.

“This is a good outcome for the Bonikro operation and underpins its value prior to the completion of the expansion feasibility, and we expect the current drilling programme to further enhance the resource base by year-end,” said Lihir CEO Graeme Hunt.

“Bonikro is an important centre for Lihir’s operations in Cote d’Ivoire and provides a platform for future growth.”

At full production, the Bonikro mine produces 120 000 oz/y gold.

The Hiré permit is located 12 km from the Bonikro permit, and its resources are likely to add to the Bonikro mineral inventory.

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