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design of economical regrind system

design of economical regrind system
confidential client

oversize grinding system processes lower-grade ore

When a northern Minnesota mineral processing facility needed a more economical regrind system for iron-ore processing, Barr developed one that incorporates a new launder, new sumps and pumps, a cyclone cluster, four new magnetic separators, and a vertical mill. The Vertimill reduces the recirculating load in the primary grinding circuit, increases the capacity of the primary feed up to 30 percent, is more economical to operate, and has a smaller footprint than a horizontal mill.

For this process, a new launder was designed to collect oversized material from the fine screen’s nine grinding lines and bring it to a cyclone feed sump. This pumps the material to a cyclone cluster that sends undersized material to four new magnetic separators and oversized material to the vertical mill. After grinding the material, the mill sends it to the cyclone feed sump where it is routed through the cyclones again, passing through this loop until it is small enough to be directed to the magnetic separators and continue through the pellet-making process. 

Our design added two new concentrate sumps and pumps, extended an existing reject conveyor by 200 feet, included a stacker for rejects from primary mills, and housed it all in a building addition.

This project marked the first Vertimill installation in the US for iron ore, and since it’s startup in late 2000, the system has helped our client maintain a consistent production rate while processing a lower-grade ore.