Modern Mining January 2018

PLATINUM

systems will be employed, contributing both to enhanced on-mine safety as well as cost effectiveness. In mid-2017, the measured resource for the UG2 in the area to be mined stood at 129 Mt (12,65 million ounces), while the proven reserve is estimated at almost 70 Mt (5,94 million ounces). The mea- sured resource for the single Merensky module is almost 12 Mt (1,07 million ounces) and the proven reserve is 9,84 Mt (0,82 million ounces). By late 2017, the cumulative capital expended had reached R733 million, and saw the central boxcut nearing comple- tion while development work had started on all seven adits (with the contractor responsible for the decline system being Murray & Roberts Cementation). Work has also progressed well on the 4 000 tonne capacity ore silo, which will feed an aerial rope conveyor system – an inno- vative feature of the project – to transport ore to the concentrator plant. The specialised ‘RopeCon’ aerial rope conveyor, supplied by Austria-based Doppelmayr Transport Technology, is part of the company’s effort to reduce the project’s environmental impact. Over 14 km of the Merensky and UG2 reefs outcrop in the Groot Dwars River valley – an area of considerable conservation importance in terms of aquatic and terrestrial biodiver- sity. According to the project’s environmental impact assessment, the area falls within the Sekhukhuneland Centre of Plant Endemism – the third richest in ultramafic induced endemic plant species in South Africa – and the National Freshwater Ecosystem Priority Area. In addition, the Mpumalanga Biodiversity Conservation Plan identifies this area as signif- icant and irreplaceable, while the Mpumalanga Tourism and Parks Agency conservation plan also classifies the area as irreplaceable. The RopeCon – which will cover a distance of 4,9 km to deliver ore from the central por- tal complex to the concentrator and integrated chrome extraction plant – will minimise the impact on the terrain it crosses over, as the 11 tower structures supporting the conveyor will be the only points of contact with the ground. The conveyor, with a width of 800 mm and a speed of 4,2 m/s, will have a capacity of about 444 000 tonnes per month. (Doppelmayr recently announced that it would be design- ing and constructing a second RopeCon system – to start operating in 2020 – to tie in with the first.) Included in the infrastructure under

construction are a north access road – where final surfacing is in progress – and a south access road, both totalling 12,5 km in length. A new 132 kVA power line will be constructed from Booysendal North to Booysendal South to supply the mine with electricity; construction will be completed towards the end of the 2018 financial year. Maximum nominated demand is currently 29 MVA, but the company empha- sises that energy efficiency remains a priority at the mine. While Dunne acknowledges that the immediate future for platinum is unclear, he emphasises that future sustainability depends on containing production costs; Booysendal South aligns well with the positioning of Northam operations to leverage platinum’s next upward cycle. “We aim to be ‘first to market’ and capable of delivering up to an annual one million ounces of PGMs when demand for newly-mined metal recovers, as we believe it will,” he says. Report by Paul Crankshaw, photos courtesy of Northam Platinum

Workings for the foundations of one of the RopeCon towers – to date, this structure has absorbed 2 200 cubic metres of concrete and 190 tonnes of reinforcing steel. The RopeCon systemwill overcome the topographical challenges at the Booysendal South site and reduce the project’s environmental footprint.

Re-treating chrome tailings Among the assets acquired from Aquarius Platinum in the purchase of Everest mine was the tailings storage facility – nowpart of Booysendal South – containing 8,7 Mt of waste; this is now being hydro-mined and repro- cessed in a R100 million capex project to extract some 1,3 Mt of chrome concentrate. Hydro-mining and chrome spiralling started in September 2017 and it is planned that by April 2018 the entire plant will be commis- sioned; PGMs will then also be processed. 

Top projects

January 2018  MODERN MINING  65