Yoctolux Collieries in Mpumalanga, South Africa, has achieved improved yields and production throughput with the installation of a Cavex® 500CVXT20 DM hydrocyclone from Weir Minerals Africa, the OEM says.

Part of the Tala Group, the open-pit coal mine was looking to improve the performance of its dense media separation (DMS) circuit in its Wash Plant 1. The existing 610 mm cyclone, installed during the mine’s initial design phase, had an operational life of only six months between refurbishments.

Members of the Weir Minerals Middelburg branch and hydrocyclone product team conducted a site audit, revealing the incumbent cyclone was operating inefficiently. A “wash-ability” analysis showed that an improved yield could be achieved using the Cavex hydrocyclone technology on the DMS circuit, Weir said, with the customer specifying that the product would have to offer improved separation efficiency, increase wear life and match the existing cyclone footprint.

Following a proposal that included dense media (DM) hydrocyclone simulations, a Cavex 500CVXT20 DM hydrocyclone was installed in August 2017. Manufactured from mild steel, it is lined with 25 mm slip-casted radius ceramic tiles manufactured with 92% alumina content.

To date, the hydrocyclone has achieved higher separation efficiency through an average 15% yield increase, according to Weir. It has achieved an overall average of 75% yield for both of the mine’s coal types – grains and peas. This compares favourably with the 65% achieved previously by the competitor’s cyclone, Weir said.

There has been a 49% throughput increase in production tonnage, from 78 t/h to 116 t/h as a result of the reduced turbulence in the hydrocyclone’s design. The mine has also seen significant wear life improvement, with the Cavex DM hydrocyclone requiring only a spigot replacement after nine months, according to the equipment manufacturer.

So satisfied was the management at Yoctolux Collieries that they placed an order for an additional Cavex 500CVXT20 DM hydrocyclone in May 2018. This replaced the competitor’s cyclone on Wash Plant 2, with the replacement based on the improved metallurgical and operational benefits obtained by the Cavex hydrocyclones.