Detailed engineering studies are under way on the initial 770 000 t/y mine and concentrator at TSX-listed Ivanhoe Mines’ South African subsidiary Ivanplats’ tier-one Platreef palladium, rhodium, nickel, platinum, copper and gold project in South Africa.

This work is being done in parallel with the changeover of Platreef’s initial shaft – Shaft 1 – into a production shaft, with completion expected this month.

The initial underground development focus at Shaft 1 will be on the first ventilation raise and ore passes, connecting the 750 m level to the 950 m level.

Mining access ramps will connect the haulage levels with the mining sublevels and other infrastructure. The mining sublevels will be developed from the ramps at regular vertical intervals in the production areas. Drilling and extraction levels for stopes will be driven from the sublevels.

Ivanplats completed the sinking of Shaft 1 in June 2020, reaching a final depth of 996 m below surface. Shaft 1 is located about 450 m away from a high-grade area of the Flatreef orebody, which will provide initial mining areas for Phase 1 production in 2024.

"For Ivanhoe Mines, achieving first production at Platreef will mark the next milestone in the journey to become a new-age, major diversified mining company,” said Ivanhoe co-chairperson Robert Friedland at the thirty-first BMO Global Metals & Mining Conference in Florida, in the US, on February 28.

The Platreef project, which includes an underground deposit of thick, high-grade platinum group element (PGE)/nickel/copper/gold mineralisation – is in the northern limb of the Bushveld Complex, about 11 km from Mokopane and 280 km northeast of Johannesburg.

Mining zones in the current Platreef mine plan occur at depths ranging from about 700 m to 1 200 m below surface. Mining will be carried out using mechanised methods, including long-hole stoping and drift-and-fill. Each method will use cemented backfill for maximum ore extraction.

Ivanplats said on February 28 that the first delivery of the initial battery-electric underground fleet was expected “imminently”, and that the first blast on the 950 m level was planned for April.

Following the completion of the changeover of Shaft 1, the company said off-shaft development would start in April with the initial aim of enabling construction of the critical ventilation Shaft 1.

The 996-m-deep, 7.25-m-wide ventilation shaft would not only enable future development of underground infrastructure but was planned to be the secondary means of egress from the mine until the second, larger shaft – Shaft 2 – was complete.

Earthworks for the first concentrator are planned to begin in the second quarter, followed by civil works and the ordering of long lead-time items in the second half of the year. First ore feed to the concentrator is planned for the third quarter of 2024.

Phase 1 production is estimated to average about 113 000 oz/y of platinum, palladium, rhodium and gold (3PE+Au), as well as five-million pounds of nickel and three-million pounds of copper.

While the 770 000 t/y initial mine will operate using Shaft 1, the sinking of Shaft 2 is expected to drive the Phase 2 expansion to 5.2-million and will progress in parallel to ongoing production.

The newly released Platreef 2022 feasibility study envisioned that Shaft 2 would be equipped for hoisting in 2027, which is an acceleration of the schedule by about 18 months when compared with the 2020 preliminary economic assessment, coming online just over three years from first production of Phase 1.

The company explained that, once Shaft 2 was complete, two 2.2-million-ton-a-year concentrator modules would be commissioned, while the initial concentrator is ramped up to its full capacity of 770 000 t/y. This would increase the steady-state production to 5.2-million tons a year.

Ivanplats claimed that the Phase 2 expansion would result in Platreef becoming the world's fifth-largest primary platinum-group metals mine on a palladium-equivalent basis, with forecast production of more than 590 000 oz/y of 3PE+Au, plus more than 40-million pounds of nickel and copper.

EXPANSION PLANS

The company added that, if the remainder of the indicated resources were to be converted to reserves, it would provide an opportunity to “massively” expand production.

As development of the project progresses, Ivanplats will undertake additional drilling from underground with the goal of increasing the confidence of the current mineral resources, as well as to expand the resource base.

Additional studies will follow up on the previous work that envisaged further phased expansions based on updated reserves.

“Platreef still has vast potential to significantly expand the already enormous resource base . . . as well as a plethora of new nickel-sulphide exploration opportunities, many of which are near surface," Friedland concluded.