When cost margins were eating away the mine’s profits, Hildebrand Wilhelm, ore processing manager for QKR Namibia Navachab operations and his team started to employ a new technology in mining: sensor-based ore sorting should upgrade the gold grade and remove useless material that will not burden on the following processes and should result in cost savings.

Since 2016 two Steinert XSS-T x-ray transmission bulk sorting systems have been installed in a 200 t/h production plant to upgrade the low-grade stockpile material. “What has amazed us is that the machine is very robust. We are getting a good reliability on the units and 80% to 90% running time is absolutely possible,” Wilhelm says.

“I think it is a challenge to pursue new technologies in a very conservative mining environment. It is very important that you are confident in the people that you work with.”

Navachab gold mine took a risk and learned that with Steinert’s capabilities it was possible to innovate in the mining industry and be able to cut processing costs.

“We have set up the plants in such a way that we get about 25% mass-pull to concentrate and we get an average of 70% gold recovery with this kind of set up – that makes sense to us. That is a profitable operation. We treat the material to the XRT machines and, in general, we double the grade of our input material which is where the value is generated because then, with the doubled grade, the material can be profitably treated by the processes that come after that.”

New MSF pilot plant with Steinert KSS | XT CLI at Afritin

It is a combination unit, capable of handling a throughput of between 5 t/h and 100 t/h with a 1 m working width. The unit includes an x-ray transmission (XT) sensor to identify atomic densities, two optical sensors - a color sensor (C) and a laser sensor for 3D shape information (L) - and an induction sensor (I) that detects metals. The unit was developed as a response to increasingly complex requirements in material separation.

“Steinert’s technology has taken a leap forward by offering multiple sensors on a single platform. This allows for higher classification abilities, higher processing capacities, higher recoveries and improved grades,” explains Steinert area sales manager for Africa John Knouwds.

“Having the correct combination of sensors opens up further possibilities to clean up generated products beyond the extent originally required or to add sorting stages previously assessed as not feasible.”

Specially developed Steinert software also allows for the design of new detection-algorithms, which can be implemented as needed to cope with new challenges.

For further details please write to john.knouwds@steinert.de or meet John and our Steinert Team at Mining Indaba and DRC Mining Week.