Grinding Mill 20 To 50 Tons Per Hour 3 A cement grinding mill A with a capacity of 50 tons per the secretary works 2 400 hours a year and the executive 3 000 hours a year 3 A cement grinding mill A with a capacity of 50 tons per hours utilizes forged steel grinding balls costing P12 000 per ton which have a wear rate of 100 grams per ton