Mining at the Ivanplats’ Platreef Project will be performed using highly-productive mechanized methods, including long-hole stoping and drift-and-fill. Each method will utilize cemented backfill for maximum ore extraction.
The production plans in both the PEA’s initial five-year drift-and-fill mining operation hoisting from Shaft 1 and the expansion when Shaft 2 is available, are focused on maximizing higher-grade areas, which was achieved through optimization based on stope locations, stope grades, mining method, and zone productivities.
The orebody was targeted to recover approximately 125 million tonnes at the highest net smelter return. The ore will be hauled from the stopes to a series of internal ore passes and fed to the bottom of the shafts, where it will be crushed and hoisted to surface.
Mining zones in the current Platreef mine plan occur at depths ranging from approximately 700 metres to 1,200 metres below surface. Initial access to the mine will be via the 996-metre-deep, 7.25-metre-diameter ventilation shaft (Shaft 1) that recently has been sunk to its final depth.
Once expanded mine production is achieved, primary access to the mine will be by way of a 1,104-metre-deep, 10-metre-diameter production shaft (Shaft 2). During mine production, both shafts also will serve as ventilation intakes. Three additional ventilation exhaust raises (Ventilation Raise 1, 2, and 3) are planned to achieve steady-state production.
The Platreef Project is owned by Ivanplats (Pty) Ltd (Ivanplats), which is 64%-owned by Ivanhoe Mines. A 26% interest is held by Ivanplats’ historically-disadvantaged, broad-based, black economic empowerment (B-BBEE) partners, which include 20 local host communities with approximately 150,000 people, project employees and local entrepreneurs.
A Japanese consortium of ITOCHU Corporation, Japan Oil, Gas and Metals National Corporation, and Japan Gas Corporation, owns a 10% interest in Ivanplats, which it acquired in two tranches for a total investment of $290 million.
The construction of the 996-metre-level station at the bottom of Shaft 1 was completed in July 2020. The completed Shaft 1 is located approximately 350 metres away from a high-grade area of the Flatreef orebody that is planned for bulk-scale, mechanized mining. The three development stations that will provide initial, underground access to the high-grade orebody have also been completed on the 750-, 850-, and 950-metre levels.
The changeover construction at Shaft 1, initially delayed following an accident on September 14, 2020, is progressing to plan and is on schedule for commencement of rock hoisting early in 2022. All equipment for the shaft changeover has been procured and is on site. The detailed engineering designs for the shaft changeover have been completed, reviewed and approved. The changeover work within the shaft will be conducted by Platreef’s experienced owners’ team.
The winder that was used to successfully sink Shaft 1 will be converted and re-equipped to function as the permanent rock, personnel and material winder for the life of mine. The shaft will be equipped with two 12.5-tonne skips (with hoisting capacity of 825,000 tonnes per year) and an interchangeable personnel and materials cage to accommodate the movement of personnel and materials up and down the shaft during the initial phase of mining.
The shaft will be equipped using rope guides for the main rock, personnel and materials conveyances. The stage and winder ropes used during the sinking phase have been removed, and the equipping stage, new permanent guide-ropes and new permanent hoisting ropes have been delivered to site. Further to this, an auxiliary winder will be installed mainly to function as a man winder during the main rock hoisting cycle.
The construction of the winder foundations is underway and will be completed in time for the auxiliary winder installation and commissioning. The headgear, both winders, equipping stage, conveyances and control systems will comply with the highest industry safety standards, with proven and tested safety and redundancy systems in place.
Newly-designed rock chutes will connect the conveyors feeding the concentrator plant and the waste rock area, from where the rock will be converted to cemented backfill and used for protection berms to contain storm water and reduce noise emissions.
The new ropes and the newly-designed and constructed equipping stage have successfully been installed. The equipping in the shaft is expected to commence in May 2021 for completion by end of March 2022. Following the completion of the changeover work in the underground stations, and establishment of the ore and waste passes, lateral underground mine development will commence toward high-grade ore zones.
Early-works surface construction for Shaft 2 began in 2017. It includes the excavation of a surface box-cut to a depth of approximately 29 metres below surface and construction of the concrete hitch for the 103-metre-tall concrete headgear (headframe) that will house the shaft’s permanent hoisting facilities and support the shaft collar. Platreef’s initial budget for 2021 of $59 million, which included $10 million for commencement of headframe construction for Shaft 2, has been increased to $76 million with additional budget allocated toward detailed engineering designs, an alternative downstream processing option study and execution readiness. The Shaft 2 headframe construction, from the hitch to the collar level, recently commenced and is scheduled for completion in April 2022.
In February 2021, Ivanplats signed a non-binding term sheet with Orion Mine Finance, a leading international provider of production-linked stream financing to base and precious metals mining companies, for a $300 million gold, palladium and platinum streaming facility. The stream financing remains subject to completion of legal due diligence and structuring, as well as negotiation and execution of definitive documentation. The streaming facility is planned to be drawn down in four separate tranches, as needed, in parallel with the engineering studies to upgrade the Platreef 2020 PEA to a feasibility study and the changeover of Platreef’s Shaft 1 to a production shaft.