Mill Horsepower Consumption Derivation

The proper mill size for a given application is dependent upon (a) the power per ton required to achieve the grind and (b) the hourly throughput required of the mill.

Determination of the power per ton to achieve a grind is a starting point in selecting a mill size. This parameter is commonly expressed in kilowatt hours per short ton (kwh / st). The accuracy of mill sizing is dependent upon the determination of this parameter. The relationship between power required and mill-horsepower-draw is straightforward and is derived from basic physics as follows:

The action of the grinding charge within a mill can be compared with the model used in the derivation of the horsepower equation. The differences in mill action between the model and actual situation account for the discrepancies between calculated and actual horsepower. For this reason. Mine and Smelter includes in its horsepower calculations, correction factors based on mill diameter, mill type and experience. Calculated horsepower vs. mill size is shown later.