Ivanhoe Mines has announced that the company’s South African subsidiary, Ivanplats, has successfully completed the sinking of Shaft 1 to a final depth of 996 m below surface, at the company’s palladium, platinum, nickel, copper, gold and rhodium Platreef mining licence. The Platreef Project, which contains the thick, high-grade, flat-lying, underground Flatreef Deposit, is a Tier One discovery by Ivanhoe Mines’ geologists on the Northern Limb of South Africa’s Bushveld Igneous Complex; the world’s premier platinum producing region.
Underground mine development work now will focus on the construction of the 996 m level station at the bottom of the shaft, with final completion forecasted by the end of July 2020, well ahead of the contractual schedule. The shaft can then be reconfigured and equipped for rock, personnel and material hoisting. The new auxiliary winder for the 7.25 m diameter Shaft 1, which is scheduled to be delivered to Platreef later this year, will be used to assist in equipping the shaft and thereafter for logistics, shaft examination and auxilliary functions. The auxiliary winder will provide a second means of ingress and egress from the shaft after removal of the stage winder.
Shaft 1 is located approximately 350 m away from a high-grade area of the Flatreef orebody, planned for bulk-scale, mechanised mining.“The Platreef Project has long been recognised as one of the world’s largest deposits of high-grade platinum-group metals (PGMs), nickel and copper. With the sinking of Shaft 1 now complete, we are exploring near-term development pathways at Platreef that will allow us to expedite production at the next world-classmine on the Northern Limb,” said Ivanhoe Executive Co-Chairman Robert Friedland. “We are particularly pleased that the project remains ‘Fall-of-Ground’ incident free since shaft-sinking operations began in July 2016, which is a tribute to the excellent work by the Platreef Project team and its South African sinking contractor, Moolmans.”
Ivanhoe is updating the Platreef Project’s 2017 definitive feasibility study (DFS) to take into account development schedule advancement since 2017 when the DFS was completed, updated costs and refreshed metal prices and foreign exchange assumptions. Concurrently, Ivanhoe is finalising a Preliminary Economic Assessment (PEA) for the phased development production plan for the Platreef Project. The plan targets significantly lower initial capital, to accelerate first production by using Shaft 1 as the mine’s initial production shaft, followed by expansions to the production rate as outlined in the 2017 DFS.
The re-evaluation is being done in parallel with the ongoing mine development work to access the thick, high-grade, flat-lying Flatreef deposit that was discovered in 2010 and outlined in the Platreef 2017 Feasibility Study. “The pending study will assess phased development options at Platreef with substantially lower upfront capital. The goal is to prioritise near-term production while safeguarding our strong balance sheet. We are confident that the project will, in time, become one of the world’s largest and lowest-cost primary producers of platinum-group metals and provide long-lasting and meaningful benefits to all of our stakeholders, including the 20 local communities − comprising approximately 150,000 local Mokopane area residents − that are our equity partners,” Friedland added.
Planned mining methods will use highly-productive, mechanised methods, including long-hole stoping and drift-and-fill mining. Each method will utilise cemented backfill for maximum ore extraction. The ore will be hauled from the stopes to a series of internal ore passes and fed to the primary ore silos adjacent to Shaft 2, where it will be crushed and hoisted to surface.
Shaft 1 reached the top of the high-grade Flatreef Deposit (T1 mineralised zone) at a depth of 780.2 m below surface in Q3 2018. The thickness of the mineralised orebody (T1 and T2 mineralised zones) at Shaft 1 is 29 m, with grades of platinum-group metals ranging up to 11 g/t 3PE (platinum, palladium and rhodium) plus gold, as well as significant quantities of nickel and copper. The 29 m intersection yielded approximately 3,000 t of ore, estimated to contain more than 400 oz of platinum-group metals. The ore is stockpiled on surface and is being used for metallurgical test work.
The development of the three primary mining access level stations has been completed with only the 996 m spillage clearing level remaining, which will be completed by end July 2020. The three development stations will provide initial, underground access to the high-grade orebody. Shaft 1 changeover detailed designs are being completed and will enable Shaft 1 to be configured for permanent hoisting and dewatering.
The mining zones in the current Platreef Mine plan occur at depths ranging from approximately 700 m to 1,200 m below surface. When completed, Shaft 2 is expected to provide primary access to the mining zones; secondary access is expected to be via Shaft 1. During mine production, both shafts also are expected to serve as ventilation intakes. Three additional ventilation exhaust raises are planned to achieve steady-state production. Ivanplats received its Integrated Water Use Licence in January 2019, which is valid for 30 years and enables the Platreef Project to make use of water as planned in the 2017 DFS.