Pedra Branca iron oxide copper gold deposit is hosted within the Carajás Mineral Province which is located in the southern part of the Amazon Craton. Locally the craton is overlain by metavolcanic–sedimentary units of the Rio Novo Group and the 2.76 Ga Itacaiúnas Supergroup. The Itacaiúnas Supergroup hosts all the known Carajás iron oxide copper gold deposits and is thought to have been deposited in a marine rift environment. The Carajás Mineral Province represents one of the best endowed mineral districts in the world and contains the world’s largest known concentration of iron oxide copper gold deposits including the, Salobo, Igarapé Bahia, Alemão, Cristalino, Gameleira, Furnas, Alvo 118, Antas, Pedra Branca, Santa Lucia and Pantera deposits.

The Pedra Branca deposit consists of two distinct bodies, Pedra Branca East (PBE) and Pedra Branca West (PBW). Both exhibit typical IOCG features such as hydrothermal alteration types (sodic, calcic-sodic, calcic-ferric and potassic-ferric) and mineralisation style characterised by chalcopyrite + pyrrhotite ± pyrite in semi-massive levels, blebs, strings and disseminations.

Simplistically the geology of the PBE deposit is characterised by a series of strongly foliated to gneissic granitic composition footwall rocks to the north and a foliated diorite to granodioritic composition series of hanging wall rocks to the south. Between these two units a felsic mylonite shear zone is located which also hosts hydrothermal ........

The proposed mining method is sublevel stopping in longitudinal layouts with backfill in bench stopping configurations where mining starts in the base of the panels and progresses laterally and upwards in a bottom-up sequence. Backfill will be of waste from development until the third panel (Level 925), after which point it will be necessary to bring waste from the exhausted Antas Mine.

The stope optimisation was run with minimum mining widths as of 3 metres (0.5 metres dilution to hanging wall and footwall) and minimum 8 metres wide pillars between adjacent stopes in parallel lenses.

A minimum mining width of two metres is assumed with a minimum 8 metre pillar width between adjacent stopes in parallel lenses. Mining recovery is assumed at 90 percent to account for the rib pillars and ore losses. Dilution for stopes is assumed as an envelope obtained from the expansion of the stope walls for 0.5 m out towards each host rock. Development dilution is an assumed at 15 percent additional tonnes at a zero grade.

In Carajás East, Pedra Branca delivered strong operational performance with the mine ramping up ahead of schedule and multiple stopes now consistently in production as the capability of our underground operators grows. Exploration efforts continued to focus on satellite opportunities while study work on Santa Lúcia, a potential additional satellite mine for the Carajás East hub, is nearing completion.

Mining of the Antas North op ........

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