To decouple particle breakage from mass transport in a ball
mill, and to collect data of size reduction occurring in a ball mill,
batch grinding tests were conducted using a standard Bond ball
mill (305 mm internal diameter 305 mm length) installed at
the JKMRC pilot plant. Two ore samples collected from gold–copper
comminution plant surveys (Samples A and B) were used for
the batch grinding tests and the JKFBC characterisation tests. Standard
Bond ball mill test procedures were performed, with an
exception that full size distribution of the mill content in each
cycle was measured, to provide detailed batch grinding data for
each cycle (in a standard Bond ball mill test, product size distribution
is only measured for the last cycle). The product of 0.15 mm
material was removed after each cycle of grinding, and the same
amount of fresh feed was topped up to form a feed for the next
cycle. A total of seven cycles were performed for each sample when
an equilibrium stage was reached.