Kansanshi, Africa's largest copper mine, is located near Solwezi in Zambia. The mine site is very remote, so getting parts and replacement material to site is time consuming and costly.
Of particular concern for the operation was excessive wear in the tailings lines, as well as the overflow tank in the continuous counter-current decantation (CCD) circuit.
There is approximately 8km of tailings pipes running from the plant to the tailings dam. The mine had previously lined its pipes with a combination of high-density polyethylene (HDPE) liners and alumina ceramic tiles. These, however, only achieved a wear life of approximately nine months.
Kansanshi approached Weir Minerals Africa for an alternative solution and the company, which has a long-standing relationship with the mine, specified Linatex premium rubber to line the tailings pipeline. Known for its excellent wet abrasion properties, Linatex rubber also requires a considerably shorter time for lining installation when compared to alumina ceramic tiles.
The lining was completed well within the allotted time, saving Kansanshi unnecessary and costly plant downtime.
After 36 months in operation, the Linatex lining showed minimal signs of wear, and the installation has reduced the mine's total ownership cost by over R1.6 million (US$107,000) per year.
Kansanshi also needed a more cost-effective wear solution for the overflow tank in the CCD circuit. This had previously been lined with alumina ceramic tiles, which only lasted between 60 and 90 days. The tiles were wearing away quickly due to the high impact and abrasion of the stones and sand flowing through the tank. Wash out between the tiles was preventing the tiles from adhering to the metal substrate and the subsequent damage to the tank required repair work.
In response, the Weir Minerals team specified Linagard nitrile-based rubber (NBR). The expected cost savings from the increased production and reduced maintenance offset the installation costs.
The Weir Minerals technical lining manager was on site for the duration of the tank re-lining to provide technical assistance to Kansanshi's maintenance team.
Since installation, the Linagard NBR 30 has lasted 36 months without any visible signs of wear. According to Weir Minerals, this represents 18 times longer wear life than the previously installed alumina ceramic tiles and eliminated the need to repair the tank every 2-3 months.
Kansanshi has experienced significantly reduced downtime and increased productivity since the installation of the Linatex solutions, and mine maintenance personnel can focus on other areas of the mine. Weir Minerals stated that the mine's costs have been reduced by R10.4 million (US$698,000) per year with its Linatex solutions.