Modern Mining: Featured News

Work is progressing apace at SepFluor’s Nokeng mine in northern Gauteng since the project was launched in mid-2017; hopes are that this R1,7 billion initiative could signal the start of South Africa becoming a global fluorspar player. Modern Mining visited the mine site with SepFluor CEO Rob Wagner to get an update.

It has been a dozen years since Gauteng – the historic home of South Africa’s world-famous gold mining industry – saw a new mine rising from its earth, and that in itself may have been reason enough for Nokeng to be in the headlines during 2017. In fact, there are a few more exciting reasons to take note; for instance, the mine is relatively high grade and its mining process fairly low cost, suggesting that the return on investment will be considerably better than most operations in the country’s beleaguered minerals sector.

Aerial view of part of the Nokeng site showing the conveyor culvert being constructed under the D567 provincial road, beyond which the site for the primary crusher is being prepared.

But looking further ahead, it is SepFluor’s plan for an aluminium tri-fluoride (AlF3) beneficiation facility in nearby Ekandustria that is likely to soon be raising eyebrows, and Wagner expects the economics of this venture to be clearer by mid-2018. The initial plan would be for the company’s Nokeng mine – and subsequent operations – to feed 130 000 tonnes a year of acidspar (calcium fluoride or CaF2) into the facility, producing over 17 000 tonnes a year of surplus anhydrous hydrogen fluoride (AHF) and 216 000 tonnes a year of anhydrite (CaSO4) as a by-product.

The beneficiation works would also draw over 42 000 tonnes a year of AHF and produce – through a process involving imported aluminium hydroxide – some 60 000 tonnes a year of aluminium tri-fluoride for local and international aluminium smelters.

“We have been working on these plans for some time, and are well positioned to implement this initiative,” says Wagner. “The plant in Ekandustria already has an emissions permit and a Water Use Licence, and we have a project manager with plenty of practical experience in this field.”

The proposal ticks all the boxes for technological innovation and local beneficiation of minerals, so it is hoped that the relevant government departments – as well as developmental and commercial financial institutions – give it the support it warrants.
Back at the Nokeng project 80 km north of Pretoria, the work is steaming ahead with a firm eye on the clock. To expedite the supply of power, the mine is ‘self-building’ the 14 km, 132 kV overhead line in collaboration with Eskom. This is only the third self-built line in the country but, at a cost of R80 million, will keep the mine on schedule and hold down the risk of schedule over-runs.

The project has been long in preparation, Wagner acknowledges, and it is important to consolidate the credibility that his team has built. With its mining right issued and its Social and Labour Plan approved in 2011, Nokeng received its final approvals in 2013. In the recent difficult investment climate, it took until the middle of 2017 for the financing to be completed – requiring an onerous R700 million-odd in equity to secure the rest of the project’s cost in debt from South African, Dutch and German lenders.

Contractors have wasted no time in getting going, with Group Five Construction initiating earthworks, civils and other site work in the second half of 2017. A joint venture comprising DRA Projects and Group Five was awarded the engineering, procurement and construction (EPC) contract for the mine. Two boreholes are operational – in a well-field that will include 14 boreholes – and a potable water plant is now commissioned to deal with the high fluorine content of the raw water.

Road infrastructure is being upgraded to suit the mine’s needs, and the earth mat for the on-site substation has already been completed. A tailings dam contractor is to be appointed in the next few weeks; the mining contractor, to be appointed shortly, will be on site by early in the second quarter at the latest.

Mining will focus on two high-quality, adjacent haematite-fluorspar deposits – Plattekop and Outwash Fan. At the Plattekop property, there is a 20 m thick layer averaging 38,16 % calcium fluoride and 25 % iron, over a 200 m by 400 m plateau capping Plattekop Hill which overlooks the site where the concentrator infrastructure is being constructed. Total proven reserves amount to 2,7 million tonnes (Mt) containing over a million tonnes of calcium fluoride.

A far larger, but lower grade, deposit resides at Outwash Fan, 3 km south of Plattekop; with a proven reserve of almost 9,1 Mt, this will convert to over 2 Mt of calcium fluoride. The stratiform fluorspar deposit averages 22,7 % calcium fluoride and 40 % iron.

“There is also a distinct possibility of the nearby Wilton orebody also proving economic,” says Wagner.

Mining operations will employ smaller blast intensities at shorter intervals to limit the range of the environment impact. The primary crusher is being positioned on the same side of the main road as mine operations, as this will obviate the need for mining vehicles to regularly cross this road; crushed ore will then be transported by conveyor through a dedicated culvert under the road to the secondary and tertiary crushing facilities.

A 28-m high live stockpile of 5 000 tonnes of ore will be maintained after the crushing and screening phases. Processing will comprise a fairly standard crush-mill-float method similar to that adopted by most platinum operations, says Wagner.

“An innovation at Nokeng is the use of high pressure grinding roll (HPGR) technology in our crushing circuit, which will give us an added competitive advantage,” he says. “This will help keep the iron content in the concentrate as low as possible, as this element is liberated more effectively when the ore is broken along fracture lines, which HPGR will do more effectively.”

Cold commissioning of the concentrator plant is scheduled to start in August this year, with plant construction to be complete by October when hot commissioning and production ramp up will begin; product will be transported by road to Durban for shipping.

“The first 7 000 tonnes of concentrate will be shipped to a US-based customer in January 2019,” says Wagner.

Among the first buildings to be completed will be the mine’s R24-million training centre – a spacious facility adjacent to the mine property which will train a steady flow of community members in technical skills such as building, mechanical and electrical trades up to NQF 2 level.

“It is important that the mine contributes as early as possible to skills upliftment in the area – especially as the nearby communities are generally poor and under-skilled,” he says.

Training company PMI has been contracted to train 60 local residents in three-month cycles, a model that worked well for Wagner during his tenure at a remote manganese mine in the Northern Cape.

As far as possible, local contractors are to be involved in the construction and operational phases of the mine, says Wagner, which will create over 300 fixed-term jobs during construction and about 200 permanent jobs during operation.

Nokeng will have a mine life of 19 years and the average run-of-mine feed rate will be 630 000 tonnes a year. It is anticipated that the mine will be in the lower 25th percentile on the global cost curve of fluorspar miners.

Report by Paul Crankshaw

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