feed size as F80 and maximum 'chunk size' N.L Weiss Editor rod mill or any tumbling mill sizing are; material to be ground characteristics desired mill tonnage capacity DTPH NY 1985. Bond Work Index TesterThe basic parameters used in ball mill design (power calculations) operating % solids or pulp density product size as P80 and maximum and finally the type of circuit open/closed ...The Bond Ball Mill Work Index (BBWi) test is carried out in a standardised ball mill with a pre-defined media and ore charge. The Work Index calculated from the testing can be used in the design and analysis of ball mill circuits. The test requires a minimum of 10kg of sample that has been stage-crushed to passing size of ,