Ivanplats celebrated a significant achievement on when its initial shaft intersected the top of the mineralised reef 782 m below the surface at its Platreef project on the Northern Limb of South Africa’s legendary Bushveld Complex.
Capping many years of anticipation, Ivanplats’ mine builders for the first time can see and touch a tip of the high-grade “Flatreef” ore body, with its partially identified trove of platinum group metals: nickel, copper and gold.
This article first appeared in Mining Review Africa Issue 11 2018
At an estimated thickness of 26 m in Shaft 1, the “Flatreef” ore body lends itself to full-scale, mechanised mining that is expected to drive down the project’s operating costs and enhance profits – a model that could transform the future of the PGM sector in South Africa.
The global investment market may be questioning the need to develop new, large-scale greenfield PGM mines in an era where most of South Africa’s high-cost platinum mines are under significant financial pressure as a result of low prices and declining demand for the commodities.
Some observers predict that 40 to 50% of current PGM supply ounces will be lost in coming years as their uneconomic status escalates.
“Narrow-vein Merensky mines, typical across the Western Limb, are under enormous pressure to reduce costs and sustain their production methodologies.
"I believe high-quality, low-cost mines, situated in the Eastern and Northern limbs of the Bushveld Complex, will supplement this lost production, taking the future of PGM mining in an entirely new direction,” says Ivanplats’ Vice President & Project Director Gerick Mouton.
Located on the Northern Limb of the Bushveld Complex and adjacent to Anglo American Platinum’s Mogalakwena mine, the Platreef project will mine a strongly mineralised, polymetallic belt that extends northward from the town of Mokopane for more than 30 km.
Platreef represents a new era; it will comfortably operate on the low side of the cash-cost curve and generate healthy profits and a full return on investment.
International engineering firm DRA Global first became involved in the early stages of the project through the overall management of the pre-feasibility study (PFS) and feasibility study (FS) to the NI43-101 standard in 2015, as well as the design and project support services during Shaft 1’s sinking phase.
DRA Global is continuing to partner with Ivanplats and will be responsible for the management of civil engineering, early works and associated infrastructure during the Shaft 2 box cut and hitch construction phase.
DRA also has been involved in the N11 access road, perimeter fencing, tailings storage facility (TSF) corridor fencing and a new, modern concept design for the community skills development and training facility located close to the mine.
The Flatreef ore body is visible to the naked eye
Work to develop the Platreef mine has been a massive labour of love, to which Mouton and the Ivanplats team have been committed since discovery of the ore body was first confirmed eight years ago and the subsequent start of development in 2013.
“In a market where deep-level shaft-sinking projects are few and far between, the intersection of the Flatreef, 780 m below surface, will be recorded as one of the most significant landmark achievements in this project’s history and perhaps also in the history of PGM mining in South Africa,” Mouton says.
It is the first time that the Flatreef has been intercepted by underground mining activity. The deposit, with a strike length of 6 km, lies within a flat to gently dipping portion of the Platreef mineralised belt at relatively shallow depths of approximately 700 to 1 200 m below surface.
“We have formed a close working relationship with shaft-sinking contractor Aveng Mining and, as a single-focused team, we have truly excelled in building this shaft, on the back of a lot of skepticism from the industry.
"It has been a long journey, but we are so proud to have slowly and methodically worked through the phases and achieved our milestone goals, and we will continue to do so,” Mouton adds.
The Platreef mining team has since also delivered the first ore from the “Flatreef” to a surface stockpile for metallurgical sampling.
Patric Scheepers, senior contracts manager for Aveng Shafts & Underground, a wing of Aveng Mining, says the company values the opportunity to be Ivanplats’ mining partner on this world-class project.
“After overcoming initial learning curve constraints, this project has assisted the company to evolve into an unparalleled contract-mining specialist with the ability to deliver deep-level shaft-sinking projects safely to modern standards, and at sink rates comparable to best practise achieved anywhere.
"The focus on having skilled and highly-motivated employees whilst uplifting the local community and maintaining client relationships has been key to the success of this project to date.”
The company has placed a strong emphasis on maintaining and improving safety performance.
“This is in keeping with our primary goal of “Home Without Harm, Everyone, Everyday”, which underpins every aspect of our business,” Scheepers adds.
“We look forward to completing the first phase of this prestigious project on time and within budget and to participate in further phases and ventures with Ivanplats.”
Aveng Mining currently comprises two operating sections: Aveng Shafts & Underground and the surface-mining contracting arm, Aveng Moolmans.
Aveng plans to combine them into a single entity and trade under the very strong “Moolmans” name in the future.
This will assist to simplify the brand, capitalise on its goodwill, and further unite its operating entities.
“This milestone achievement in intersecting the Flatreef is a tribute to the excellent work by the Platreef project team and Aveng Mining,” Ivanplats’ MD Dr Patricia Makhesha reiterates.
“We now can proudly show our stakeholders and investors Flatreef’s remarkably high-grade and thick, flat-lying ore body that is ideal for safe, underground, bulk-scale, mechanised mining.”
As underground development progresses, the mine plan calls for the addition of large, mechanised mining equipment, such as 14 and 17 t load-haul-dump machines and 50 t haul trucks, to support the planned long-hole mining method.
Now that the top of the T1 reef has been intersected (there is also a T2 reef directly below T1), geotechnical drill data have indicated that the grade for the T1 mineralised zone at the Shaft 1 location is a significant 4.83 grams per tonne (g/t) platinum, palladium, rhodium (3PE) plus gold, 0.33% nickel and 0.15% copper over a vertical thickness of 12 m.
Having travelled the 780 m down the access shaft, the T1 reef is clearly visible to the naked eye.
A well-developed chromitite stringer, marking the stratigraphic contact between the T1 and T2 mineralised zones, is expected to be intersected at a shaft depth of approximately 795 m.
This will be followed by the T2 mineralised zone, which grades 4.14 g/t 3PE plus gold, 0.35% nickel and 0.18% copper over a vertical thickness of 11.26 m (at a 2 g/t 3PE plus gold grade cut-off).
The full 26 m intersection of reef in Shaft 1 will yield approximately 3 000 t of ore, estimated to contain more than 400 oz of PGMs.
The next steps
A horizontal station at Shaft 1, completed a few months ago and situated 750 m below surface, will provide initial, underground access to the ore body, enabling mine development to proceed during the construction of Shaft 2, which will become the mine’s main production shaft.
The mining zones in the current Platreef mine plan occur at depths ranging from approximately 700 metres to 1 200 m below surface.
Shaft 1’s 750 m station also will allow access for the first raise-bore shaft, which will have an internal diameter of six metres and provide ventilation to the underground workings during the mine’s ramp-up phase.
As shaft-sinking advances, two additional shaft stations will be developed at mine-working depths of 850 m and 950 m.
Shaft 1 is expected to reach its projected, final depth of 980 m below surface, complete with the stations, in early 2020.
Excavation of the adjacent Shaft 2 box cut to a depth of approximately 29 m below surface also is progressing well.
When the box cut is completed, the concrete hitch (foundation) will be built for the 103 m-tall concrete headgear that will house the shaft’s permanent hoisting facilities and support the shaft collar will commence.
Shaft 2, to be located approximately 100 m north-east of Shaft 1, will have an internal diameter of 10 m, will be lined with concrete and sunk to a planned, final depth of 1 104 m below surface.
It will be equipped with two 40 t rock-hoisting skips with a capacity to hoist a total of 6 Mt of ore per year – the single largest hoisting capacity at any underground mine on the African continent.
Headgear for the permanent hoisting facility was designed by South Africa-based Murray & Roberts Cementation.
Mouton explains that to ensure the project maintains its critical development path, the team has chosen to unbundle the complete Shaft 2 contract into smaller commitment portions.
“A major advantage Murray & Roberts Cementation brings to the Platreef reef intersect project is its overall ability, as a specialist shaft-sinking contractor, to view the entire headgear and the shaft design from a best practise constructability point-of-view,” says Murray & Roberts Cementation director of business development Allan Widlake.
Significantly, the company’s involvement in the project goes back to the feasibility stages when it carried out the full, detailed design of Shaft 2, which will be the mine’s main production shaft.
This work was subsequently followed by Murray & Roberts Cementation designing the entire shaft barrel with the full integration of the two designs, i.e. between the headgear and the shaft. Murray & Roberts Cementation has mobilised on site and is in the process of constructing the hitch foundation for the headgear itself. This will be finished in the next few of months.
Impressively, approximately 40% of Platreef’s shaft-sinking team now is comprised of employees from local Mokopane communities who had no previous mining experience.
New employees receive intensive, on-site training for underground mining and complete a workplace-safety induction program.
As with any developing mine project, Ivanplats requires additional access to project finance.
“We appointed five leading financial institutions who will make best efforts to arrange a total debt financing of up to US$1 billion for the development of Platreef’s first-phase, 4 Mtpa mine.
"Preliminary expressions of interest have been received for approximately US$900 million of the targeted US$1 billion financing.
"Negotiation of a term sheet is ongoing. Unlike most greenfield projects, we have a lot to show already and this gives investors confidence that we can deliver on our commitments,” Mouton highlights.
“Our focus is to keep advancing the Platreef project along its critical path. We remain true to our commitment to build Platreef into the world’s next great PGM mine ─ a showcase for South Africa and the international investors that have financed the exploration and development work,” says Makhesha.
Ivanhoe Mines’ executive co-chairman Robert Friedland emphasises that Platreef also has massive quantities of palladium, nickel and copper, as well as rhodium and gold – a major advantage offsetting any potential concern about the effect of low platinum prices on securing project investment.
The steady surge in the price of palladium in fact could see the metal become more valuable than gold for the first time in 16 years, and rhodium prices are near eight-year highs.
The platinum-to-palladium ratio at the Platreef mine is approximately 1:1 – again, making the mine an even more valuable asset within the PGM sector.