Background

The iron ore mines in Kiruna and Malmberget are underground mines where the ore is mined deep below the ground surface and transported to the surface by hoists. In order to safely advancing the underground tunnels forward, they are continuously secured with fiber-reinforced shotcrete, netting and rock bolts.

At the above-ground processing facilities, a number of different products are produced, including sintered pellet products but also enrichment concentrates.

To produce iron ore pellets, the ore must first be crushed, screened, milled and then mixed with additives. The pellet concentrate is then pumped in slurry form (a non-soluble mixture of water and solid particles) from the Enrichment Plant to the Pellet Plant where the slurry is finally dewatered to create pellets.

A recurring problem at the process plants (especially in the milling and dewatering processes) is the small reinforcement wires that get clogged in pumps, screens and filters. The fibers originate from the previously mentioned shotcrete used underground.

A picture from the simulation process

Our commitment

Alteco has conducted a feasibility study on how to optimize the process to minimize the interference of the fiber strands. Since the strands are magnetic, they cannot be separated using magnetism (which is normally used for screening and enrichment). Alteco has conducted a survey of existing ideas and conducted a theoretical investigation regarding their potential. The project has used, among other things, CFD-DEM simulation.