First underground TOMRA sensor-based sorter starts operations at rock salt mine

Underground sorter at K+S mine Credit: Tomra
Underground sorter at K+S mine Credit: Tomra

Salt producer K+S Minerals and Agriculture turned to TOMRA Sorting Mining to replace the existing sorting system at its rock salt mine in Grasleben, Germany.  

At the Grasleben mine, rock salt is extracted from a high-quality underground deposit and is then processed into a wide range of products, which includes food-grade table salts. For K+S, consistently achieving certified and guaranteed high purity, compliant with the strict standards of the food industry, is a priority.

“The sorting of rock salt is complex and demanding due to its crystalline properties. This leads to strong fluctuations in the appearance of the material”, Sven Raabe of K+S Minerals and Agriculture, said in a release.

TOMRA recommended using COLOR sorting technology.

“With a customized set-up of the light sources we can detect the difference in transparency of the different particles, ensuring the high quality of the rock salt,” Mathilde Robben, key account manager at TOMRA Mining, explained.

The team also advised installing the sorter in the underground mine, so that “after an initial underground sorting stage, only the coarsely crushed rock salt undergoes further grinding and sieving above ground. Only the valuable product needs to be transported in the shaft, and the final result is high-quality, pure rock salt products in various grain sizes, which are ideal for this application.”

TOMRA conducted a demonstration of the proposed solution at its Demonstration and Test Center in Wedel.

“An important factor in our purchasing decision was the positive test result achieved with the system, using transmitted light to obtain more efficient separation,” added Sven Raabe. “This has the added benefit of resource conservation. It is possible to react quickly and individually to changing situations during dismantling. We expect this to be more effective, and the ease of use of the system was also convincing.”

The order was then placed and installation completed on schedule after placing the sorter in position underground on Sept. 30.

“This is the first solution we provide for underground sorting, which raises specific challenges due to the dimensions and weight limitations of the mine shaft,” concluded Mathilde Robben.

TOMRA Sorting Mining designs and manufactures sensor-based sorting technologies for the global mineral processing and mining industries.

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