Study of degradation characteristics of Bowen Basin coal by ball mill

The degradation characteristics of South Blackwater and Ensham coal from Bowen Basin area in Central Queensland area has been studied by ball mill test with “partially-cushioned coal” and “Cushioned coal” to measure the fines generation during handling through the Gladstone Port Authority’s ship loading facility. The size of coal lumps can be reduced in ball mill tests by two mechanisms (a) volume breakage and/or (b) surface breakage. The degradation characteristics of both types of coal were the same but the rate of degradation was higher in South Blackwater coal than Ensham coal. There was a distinct difference for degradation rate between the three different sizes of South Blackwater coal in the partially-cushioned coal but the rate of degradation increased with tumbling time. The degradation rate was higher in ball mill tests with “partially-cushioned coal” than tests with “cushioned coal”. The percentage of fines (-16.0 mm) generation also increased with the tumbling time. The fines (-16.0 mm) generation was higher in the ball mill tests with “partially-cushioned coal” than tests with “cushioned coal”. South Blackwater coal produced more fines than Ensham coal in the tumbling tests.