D = mill diameter(m), inside liners. Morrell (1994) demonstrated that Equation 1 presents errors when measuring charge levels below 20%, a common situation in SAG mills. ... MORRELL S. Power draw of grinding mills – Its measurement and prediction. 5 th Mill Ops Conf, Roxby Downs, Oct, 109114 (AusIMM), 1994. Links ... IEEE Trans. Pattern ...