Model Input Model Output Pf, size in µ of the 80% passing in the fresh feed Db, the top size of the grinding media (mm) C, 200 for ball mills and 300 for rod mills Db, the top size of the grinding media (in) Wi, Work index kWh/sht VCr, percentage of the critical speed Sgs, specific gravity of feed in t/m3 Fred C. Bond Method Mill diameter in feet inside liners Mill Size Units Conversion meter feet Top Ball Size Grinding Media Calcucator Disclaimer -