SAG mill power draw models are used in mill design and grinding circuit modeling to predict how much power will be consumed by a particular mill geometry and operating configuration. This paper will compare sAG mill models by Morrell, Loveday (using ‘Power Numbers’ published by Barratt) and Austin against several published mill surveys. The purpose of the comparison is to identify the ‘fitting factors’ used by each model and to identify which mill configurations seem to better suit each model.
The importance of conducting surveys suited to model calibration will be highlighted because the review of literature shows that survey information important to modeling is often omitted.
A recommendation for the collection of data during a mill survey is presented, along with some assumptions used by the author in the absence of certain data. The benefit to mining companies of publishing their survey data, and thereby allowing modelers to improve their model calibration, is discussed.
The comparison of models requires a discussion of the measurement of power in a mill drive system as the models use slightly different bases for ‘where power is measured’. The benchmarking of models against plant ope- rations requires a similar discussion of power measurement.