Small-scale studies were conducted in laboratories with the aim to solve a difficult mixing problem in a life magnetite iron ore slurry tank. The existing 4-bladed axial flow impeller located close to the bottom can be made to provide improved off-bottom suspension and dramatically better mixing at approximately same power input when the tank baffles are removed. To maintain the same power input after removal of baffles, extending the impeller diameter or increasing speed was used. This result was implemented at LKAB's full-scale slurry tank in Sweden, achieving a successful outcome of more consistent blending, which allowed similar to 50% increase in the tank surge capacity. The large full-scale tank provided an opportunity to assess scaling up from the laboratory measurements. This scale-up confirms that laboratory measurements are in approximate agreement with full-scale observation based on using the Zwietering correlation.