POWER HUNGRY
UNDERSTANDING CHARGE MOTION DYNAMICS INCREASES SAG MILL EFFICIENCY

                                                                                                                                   

            The 36 ft. diameter semi-autogenous grinding (SAG) mill                                                                                                                SAG Mill         pictured to the right smashes up to 55,000 tons of granite
            ore per day and doing so its twin 6000 horsepower
            electri c  motors consume almost 9 megawatts of
            power - equivalent to 10 percent of all the electricity used               in Fairbanks.
    From cement, to copper and gold production- raw material size reduction is a requirement and grinding mills, the final stage in this process, are the most expensive component to operate. Improvements in SAG mill operation offers the greatest potential for cost savings.
       
These improvements have arrived in the form of computer simulations and will change the way mills are designed
maintained and operated.
                                                           
                                                                                                                          Photo courtesy of Fairbanks Goldmining, Inc. (Fort Knox Gold Mine)

Using discrete element method (DEM) mathematical  modeling techniques and Newtonian mechanics, university and private industry researchers have developed 3D software
simulations which accurately depict the simultaneous motion of all particles raising and crashing inside the mill.

mill soft image

For nearly 100 years, mill designers have relied on empirical performance data and personal experience to determine mill design specifications. Now, for the first time, a tool is available to evaluate how making such changes as modifying the lifter face angle affects liner wear, power consumption and overall cost per ton of ground material. 

To appreciate the significance and physical validity of 3D mill charge simulations
it is necessary to understand basics workings of a SAG mill, the physics of grinding mill particle trajectory, DEM modeling and how the software evolution.

WHAT IS A SAG MILL?


                SAG MILL PARTICLE PHYSICS

                                 DEM MODELING


                                            MILL SOFT - evolution of mill simulation software.

                                                                           
                                                                            APPENDIX