Amongst other high rate clarifier installations, the Stefanutti Stocks Mechanical team undertook the underground installation of a turnkey dirty water handling plant at Impala Platinum’s No. 16 Shaft near Rustenburg.

The turnkey project included the design, supply, installation and commissioning of two 6.5m diameter High Rate Clarifiers, a degritting plant, two filter press units, pumps, piping and the relevant plant electrical and instrumentation equipment. The client requested that only one 6.5m diameter High Rate Clarifier be installed, with the second unit to be installed at a later stage. Each of the clarifiers are capable of handling the full plant design flow rate of 430m³/hr and once both units are installed will operate on a duty – standby basis.

The filter presses process the clarifier’s underflow slurry and discharge the filter cakes onto a miner conveyor. The filter press, supplied by Andritz Delkor, was installed by Stefanutti Stocks. As part of the piping scope of work Stefanutti Stocks installed and welded some 60 metres of HDPE piping at a very steep angle through an annex hole.

Work took place on two levels. The clarifier and degritting plant was installed on level 27, which is 1 540m underground. The filter press installation took place on Level 28, 1 600 metres underground.