Cutting core at Platreef. Owner Ivanhoe Mines plans to develop the PGM mine in two phases, the first of which will cost an estimated $1.2 billion.
Cutting core at Platreef. Owner Ivanhoe Mines plans to develop the PGM mine in two phases, the first of which will cost an estimated $1.2 billion.

Ivanhoe Mines has reported the results of a positive, independent prefeasibility study (PFS) for a first phase of development of its Platreef platinum group metals project on the Northern Limb of South Africa’s Bushveld Complex. Ivanhoe plans to develop Platreef in three phases: Phase 1 to mine 4 million metric tons per year (mt/y) and establish an operating platform to support future expansions; Phase 2 to double production to 8 million mt/y; and Phase 3 to reach steady-state production of 12 million mt/y.

A feasibility study of Phase 1 and a prefeasibility study of Phase 2 will begin soon.

The Phase 1 PFS proposes development of a mechanized, underground mine and an initial 4-million-mt/y concentrator and associated infrastructure. Average annual production of metal in concentrates is estimated at 433,000 oz of platinum, palladium, rhodium, and gold (3PE+Au), plus 19 million lb of nickel and 12 million lb of copper. Concentrate production is planned to begin in 2019.

Pre-production capital requirements for Phase 1 are estimated at approximately $1.2 billion, including $114 million in contingencies. Platreef would rank at the bottom of the cash-cost curve, at an estimated $322/oz of 3PE+Au, net of byproducts.

Ivanhoe has declared an initial Platreef probable mineral reserve of 15.5 million oz of 3PE+Au. Mining zones in the current mine plan occur at depths ranging from approximately 700 m to 1,200 m below surface.

Access to the mine will be via four vertical shafts. Shaft No. 2 will be the main personnel, material, and ore handling shaft, while Shafts Nos. 1, 3, and 4 will be ventilation shafts. Shaft No. 1 is currently under development and will be used for initial access, bulk-sample collection, and early underground development.

Mining will utilize mechanized methods, including long-hole stoping and drift-and-fill mining. Ore will be hauled from the stopes to the bottom of Shaft No. 2, where it will be crushed and hoisted to surface.

Platreef ore is classified as hard to very hard and thus not suitable for semi-autogenous grinding. A multistage crushing and ball-milling circuit is the preferred option. The selected flowsheet has a common 4-million-mt/y, three-stage crushing circuit that feeds two parallel milling-flotation modules, each with a capacity of 2 million mt/y. Flotation is followed by a common 4-million-mt/y tailings handling and concentrate thickening, filtration and storage circuit.

The planned Platreef mine will require a workforce of approximately 2,200 within four years of the start of production. Ivanhoe intends to invest R160 million in a project social and labor plan over the next five years, including R67.2 million for development of job skills among local residents and R87.7 million for local economic development projects.

Ivanhoe Mines owns 64% of the Platreef project through its subsidiary, Ivanplats, and is directing all mine development work. South African beneficiaries of the approved broad-based, black economic empowerment structure have a 26% stake in the project, and the remaining 10% is owned by a Japanese consortium of ITOCHU Corp.; Japan Oil, Gas and Metals National Corp.; ITC Platinum Development Ltd., an ITOCHU affiliate; and Japan Gas Corp.

The Platreef PFS was prepared for Ivanhoe Mines by OreWin Pty. Ltd.; Amec Foster Wheeler E&C Services Inc.; SRK Consulting Inc.; Stantec Consulting International LLC; and DRA Projects (Pty.) Ltd.