Quality criteria in mill and at mill exit CEMENT Ball Mill. At Intermediate Diaphragm. 0% water at the intermediate diaphragm. 15 – 25% R0.5 mm (Old Holderbank Manual) HGRS / LAFARGE <5% R2mm at the end of chamber 1 is the general fineness target. OR (LAFARGE) 86-92% passing 1 mm, 80-90% passing 0.6 mm, 75-85% passing 0.5mm