Ivanhoe Mines’ South African subsidiary, Ivanplats, has completed sinking of Shaft No. 1 to a final depth of 996 meters (m) below surface at its Platreef project on the Northern Limb of the Bushveld Complex in South Africa. The project is targeting mineralization containing palladium, platinum, rhodium, gold, nickel, and copper in the thick, high-grade, flat-lying, underground Flatreef deposit.
Shaft No. 1 is located about 350 m from a high-grade area of the orebody that is planned for bulk-scale, mechanized mining. Underground mine development is currently focused on construction of the 996-m-level station at the bottom of the shaft, with final completion planned by the end of July. The shaft can then be equipped for rock, personnel and material hoisting.
A new auxiliary winder for the 7.25-m-dia shaft is scheduled to be delivered later this year.
Ivanhoe is also updating the Platreef project’s 2017 definitive feasibility study to take into account development schedule progress, updated costs, and refreshed metal prices and foreign exchange assumptions. Ivanhoe is finalizing a preliminary economic assessment for the phased-development production plan for the project. This work targets significantly lower initial capital to accelerate first production by using Shaft No. 1 as the mine’s initial production shaft.
“The pending study will assess phased-development options at Platreef, with substantially lower upfront capital,” Ivanhoe Co-Chairman Robert Friedland said. “The goal is to prioritize 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.”
Mining will be based on mechanized methods, including long-hole stoping and drift-and-fill mining. Each method will utilize cemented backfill for maximum ore extraction. The ore will be hauled from the stopes to a series of internal ore passes and fed to primary ore silos at the base of Shaft 2, where it will be crushed and hoisted to surface.
When completed, Shaft 2 is planned to provide primary access to the mining zones; with secondary access via Shaft 1. During mine production, both shafts will serve as ventilation intakes. Three additional ventilation exhaust raises are planned to achieve steady-state production.
The orebody at Shaft No. 1 is 29 m thick, with grades of platinum-group metals ranging up to 11 grams per metric ton (g/mt) platinum, palladium, and rhodium, plus gold and significant quantities of nickel and copper. The 29-m intersection by Shaft No. 1 yielded approximately 3,000 mt of ore, estimated to contain more than 400 ounces (oz) of platinum-group metals. The ore is stockpiled on surface and is being used for metallurgical test work.
The Platreef project is owned by Ivanplats Ltd., which is 64% owned by Ivanhoe Mines. A 26% interest is held by Ivanplats’ historically-disadvantaged, broad-based, black economic empowerment partners, which include 20 local host communities. Itochu; Japan Oil, Gas and Metals National Corp.; and Japan Gas Corp. hold the remaining 10%.