Mining Mirror November 2018 | Page 25

Mining in focus SepFluor’s Nokeng fluorspar mine boasts a unique flotation system, writes Leon Louw. T he Nokeng fluorspar mine, close to Rust de Winter in Gauteng, is nearing completion. The R1.7-billion project, which includes the development of two opencast mines, a processing plant, and a concentrator, is almost 70% complete. Mining Mirror visited the site recently for the official opening of a new, on-site training centre and got a glimpse of construction work at the mine and processing facility. The event was attended by the South African Minister of Mineral Resources Gwede Mantashe, who lauded SepFluor’s efforts in creating jobs and empowering the youth through providing practical artisanal training. In his keynote address, Mantashe lambasted the mainstream media for not attending events that tell a positive story about the South African mining industry. Mantashe said that Nokeng is a significant project, being the first new mine to be developed in Gauteng in the past 12 years. According to Rob Wagner, SepFluor CEO, construction at Nokeng is on time and within budget, adding that first production is expected in February 2019. Nokeng has a 12 million tonnes (Mt), SAMREC-compliant reserve and an estimated 19-year life-of- mine. About 630 000 tonnes (t) of ore containing ~27% calcium fluoride will be mined annually from surface and near-surface, initially from two deposits. About 180 000 tonnes a year of acid grade fluorspar and 30 000 tonnes a year of metallurgical grade fluorspar will be produced from the mine’s state of the art concentrator. There are not many other operating fluorspar mines in South Africa, with Nokeng’s neighbour, Vergenoeg, being the most significant. Vergenoeg is jointly owned by Spanish fluorspar producer Minerales y Productos Derivados SA (Minersa) with an 85% www.miningmirror.co.za share, and MEDU Capital (15%). The mine has a production capacity of 240 000 tonnes per annum (tpa). Upgrading fluorspar According to Johan Brits, project director at SepFluor, the Nokeng project revolves around mining and upgrading fluorspar. Fluorspar is the commercial name for calcium fluorite, which is an industrial mineral that has multiple uses in our everyday lives. Nokeng has two ore bodies, Plattekop and Outwash Fan, which will be mined as two different open pits. The ore is drilled, blasted, loaded, and hauled from the pits to the mineral processing facility, which is currently being constructed. Construction of the plant got under way on 9 June 2017 and is well advanced. According to Brits, the initial steps in the commissioning started in the first week of September, and installation and commissioning is planned to be completed by February 2019. “We have appointed a joint venture between Group Five and DRA to construct the plant, and they are doing it on an engineering, procurement and construction (EPC) basis; in other words, they are responsible for the design, supply, construction, and commissioning,” Brits explains. The processing cycle at Nokeng starts with primary crushing (jaw-crusher), followed by secondary crushing (cone-crusher). High-pressure grinding rolls (HPGR) are used in the third step, which reduces the ore to minus 6mm. Then the material is fed into a primary mill, which reduces the size further to 150 microns. The separation process involves an oxide float rather than a sulphite float, which is normally used in conventional flotation in the gold, platinum, and base metal industries. The flotation process at Nokeng uses specific chemicals and reagents, and NOVEMBER 2018 MINING MIRROR [23]