Determination of maximum zinc recovery of Vazante mine ore The ball mill used for grinding the samples and the grinding process have the following parameters and conditions Mill dimensions of 220 mm x 180 mm Length x Diameter rubber liner grinding at 67 % solids w/w 72 RPM 73 % of critical speed grinding media load of 10500 g To accurately represent the industrial plant process the target grain size of the grinding in bench tests was the