Sever Minerals engineers have assisted the Stoilensky Mining and Processing Plant in its development strategy by proposing a unique solution to increase the customer’s production capacity from 43 to 47 million tonnes of base ore.

Stoilensky Mining and Processing Plant is part of NLMK Group and carries out integrated processing of iron ore raw materials.

The Sever Minerals team plans to increase the capacity and quality of the end product by using the gravitational technology of screw separation and including weakly magnetic iron in processing. This was previously lost with the tailings* of wet magnetic separation.

The idea of using screw separators, which are used mainly in gold mining enterprises to extract free gold, is new to the iron ore industry. Sever Minerals pioneered the application of this technology to iron ore in a project for the Olenegorsk Mining and Processing Plant and proved the effectiveness of this solution. 

The gravity separation process depends on the qualitative characteristics unique to each deposit, including the specific gravity of particles, and their mineral and chemical composition. This technology has not previously been used at the plant, and industrial tests are a prerequisite for the client. Sever Minerals provided the customer with the opportunity to test the technology at their own factory.

“The testing goal was to confirm the effectiveness of the technology in an industrial environment,” says Sever Minerals’ lead engineer for classifying and separation. “We have developed an installation that is as close to real working conditions as possible. This solution is a small modular plant, fully designed, configured and assembled by engineers from Sever Minerals.”

The mobile pilot installation allows the combination and execution of various process flows and can be transferred to other plants relatively quickly for similar tests.

The unit consists of three Multotec screw separators and three Metso VT-50 vertical pump units with receiving tanks and circulating pump sleeves. An additional fourth tail tank allows the resulting products to be collected and returned to processing without losing the customer's raw materials during testing. The solution also includes WEG electric motors and Danfoss frequency converters.

The installation is easy to maintain: it is connected to the water supply of the factory, and is fitted with flushing devices and hydraulic slurry mixers in the receiving tanks. The design features of the installation mean it can be set on extended autonomous operation mode for the formation and selection of the presented samples.


*Waste products of mineral beneficiation, consisting mainly of superfluous rock, i.e. containing a minimal amount of the useful component.