http://www.engineeringnews.co.za/article/successful-slurry-pipeline-projects-for-gold-copper-mines-2012-08-03

Successful slurry pipeline projects for gold, copper mines

Published 03 Aug 12
Fluid conveyance firm Rare Group has supplied 11 762 m of 450 nominal bore (NB) and 600 NB pipelines for two mining projects in Africa.

The company is installing 3 000 m of 450 NB pipe for a new slurry pipeline at the tailings storage facility of a gold mining company operating in Ghana. The pipes were manufactured from high-density polyethylene (HDPE) and steel, and exported to Ghana from South Africa.

The pipeline is an expansion of existing infrastructure to allow the mine to handle larger volumes of slurry. It will also be used as a back-up system for possible pump failures, says Rare Group pipeline services manager Carl von Graszouw.

The project was awarded to the company in December 2011 and work began in March. It is currently 45% complete, with the balance of the installation and the commissioning of the line still to be completed.

“Swagelining technology is used to pull HDPE liners, which are welded in a string of up to 600 m, into the steel host pipe. The HDPE liner’s outside diameter is larger than the host pipe’s inside diameter. After pulling the liner through a reducing die and the tension released, the HDPE pipe will form an interference fit inside the host pipe,” explains Von Graszouw.

The project is on schedule and within budget. Von Graszouw expects it to be completed and handed over to the gold miner by early September.

However, he notes the current rainy season in the country is posing a challenge.

“We have fabricated on-site roof structures that clamp onto the pipe, which allows for the completion of the welding of the pipe collars,” he notes.

Rare Group has also partnered with Ghanaian engineering services company Swaako to provide labour for welding and general work, as well as for the operation of the plant and the equipment.

He states that the slurry pipeline project is the second of its kind undertaken by the Rare Group on this site for the gold miner and is also the fourth of its kind undertaken in Ghana, to date.

Completed Copper Project
Meanwhile, the company also completed the installation, commissioning and handover of a new 8 762 m slurry pipeline at a copper mine in Zambia, in May.

The project, which began in June 2011, comprised the supply and installation of the 600 NB pipeline, swagelined with 624 mm HDPE standard dimension ratio 17 liners, as well as the supply of 319 flanges.

The project included civil engineering work, bush clearing, as well as commissioning and formed part of plans to expand existing infrastructure at the mine.

The project was executed by Rare Group employees from South Africa, as well as Zambians employed by Rare Zambia.