Robor Pipe Systems, a division of steel, tube and pipe manufacturer Robor, supplied its patented Steel Polypipe to Zimbabwe Platinum Mines’ (Zimplats’) $460-million Phase 2 project at the Ngezi mine, in Zimbabwe.

The Ngezi mine operation, which is 87%- owned by platinum miner Impala Platinum (Implats), is situated on the Hartley Geological Complex in the Zimbabwean Great Dyke, 150 km south-west of Harare. This is estimated to be the largest of the platinum-group metal- (PGM-) bearing complexes in Zimbabwe, containing 80% of the known PGM resources in the country, two thirds of which is held by Zimplats.

The Zimplats Phase 2 project, which was initiated in 2010, entails the development of a new two-million-ton-a-year underground mine, an additionally sized concentrator and associated module, as well as other infrastructure.

This will not only add an additional 90 000 oz/y of platinum to the group’s yield but will also take production at Zimplats to 270 000 oz/y of platinum when it reaches nameplate capacity, expected in the 2015 financial year.

Robor Pipe Systems was contracted last year by project management company DRA Mineral Projects South Africa to supply the Steel Polypipe, which Zimplats will use to convey mine slurry.

Robor Pipe Systems used a team of specialists for the project to ensure that the manufacture of the pipeline met the expectations of the design engineers and contractors.

Robor Pipe Systems sales director Deon Kruger tells Mining Weekly that the Steel Polypipe, comprising high-density polyethylene (HDPE) lining on the inside, was manufactured at the company’s premises in Isando, Gauteng.

The HDPE lining is known for its large strength-to-density ratio and is commonly used to make steel pipes more corrosion resistant, he notes.

The Steel Polypipe was supplied in standard and custom lengths, during February and March this year.

The jointing method employed in the Robor Steel Polypipe system enables the flanges to be locked together, sandwiching the blow rings and HDPE stubs to create a solid joint equivalent to the pipe strength, explains Kruger.

As a result of the jointing method, the bolts are torqued to the setting applicable to steel. This eliminates ‘sponginess’ and the risk of leaks, owing to pipeline movement or the loosening of bolts.

Kruger says the HDPE-lined Steel Polypipe is suited to convey slurry in tailings lines at mine sites, owing to its high corrosion resistance.

HDPE-lined Steel Polypipes are environment friendly, as the HDPE liners are easily decontaminated and fully recyclable.

Further, the reclaimable steel pipe lends itself to being factory relined, as worn linings are easily removed and disposed of for recycling.

“The advantage of HDPE liners is that they do not depend on adhesion to steel and possible disbonding after wear, which may cause system blockages during disbonding,” says Kruger.

Besides supplying the steel piping product, Robor will provide on-site assistence at Ngezi should maintenance pipe replacements need to be undertaken.

“Robor Pipe Systems manufacture, import and supply conveyance pipe solutions with flange, ring or groove ends, for either water, steam, slurry or acids, and also offer fittings, linings and coatings for corrosion protection,” he notes.

The company holds numerous patents and international agencies. The HDPE-lined Steel Polypipe has several patents attached to the manufacturing process, pipe connections and flanging.

Robor is an ISO 9001:2000-accredited company and manufactures the products to international specifications, having repositioned itself from being a commodity company to a value-adding provider,” Robor CEO Gordon Gilmer concludes.