On a project that is destined to have a multi-generational lifespan in excess of 60 years, sustainability is an important factor in the choice of materials used to underpin its infrastructure. For the surface drainage of the rail marshalling yard at the Tonkolili iron ore mine in Sierra Leone, the mine operator, African Minerals Ltd., chose the Ridgidrain system from U.K. manufacturer Polypipe. The company supplied more than 4,000 m of 300-mm Ridgidrain perforated twin wall pipe, a product that combines both technology and sustainability.
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| Polypipe supplied more than 4,000 m of its 300-mm Ridgidrain perforated twin wall pipe to the rail marshalling yard at the Tonkolili iron ore mine in Sierra Leone for mine operator African Minerals Ltd. |
Tonkolili mine represents one of the largest iron ore resources in the world, contributing substantial economic benefits to Sierra Leone. To support the iron ore project, African Minerals has developed a significant port and rail infrastructure, which is fully integrated into the mining operations. Part of the railway, which provides the link between the mine and the port facility at Pepel, 200 km away, was originally built in the 1930s; this 74-km section has been completely replaced, and extended by a further 125 km of new rail to complete the link.
Specifying HDPE (high-density polyethylene) for the surface drainage at the new marshalling yard, African Minerals selected Polypipe through a competitive tender process. The Polypipe Ridgidrain system features a proven structured wall construction with a reduced virgin plastic content. The wall design gives high ring stiffness and strength, and has a lower weight compared to clay or concrete products, which means reduced transport and installation costs and improved health and safety benefits for installers. HDPE provides excellent resistance to abrasion and chemical attack and withstands ground movement and differential settlement. The longer pipe lengths available reduce the number of joints required, significantly reducing the risk of leakage, while its extremely smooth bore resists blockage and makes the pipework system more easy to maintain. The product supplied for the Tonkolili project was fully perforated to allow effective sub-soil drainage.
Polypipe export sales manager Philip Wood said, “HDPE is the material of choice in many mining infrastructure applications. In this case, African Minerals have specified HDPE for the rail marshalling yard in the knowledge that it is capable of delivering many years of reliable service in a very demanding environment.”
