the society contributes significantly to the education of members and non-members in the technology of coal preparation. the nsw branch conducts day general courses in newcastle, mudgee, the hunter valley and wollongong, while the queensland branch holds similar courses in blackwater, mackay, moranbah, middlemount and brisbane, both using the "principles of coal preparation" textbook as ultrafine coal cleaning recent studies have found that spirals such as the can provide an effective gravity-based separation performance for -100 mesh coal. required volumetric flow rate is around gpmstart and feed solids content should be nearly 15% by weight. currently, two u.s. coal preparation plants use spirals in this application.the setting was an open cut coal mine in queensland, australia in a daily commuting environment of approximately minutes commuting time by car one way. study population. the study focused on three work areas in the mine: the mining sector, the maintenance sector, and the coal preparation plant the work tasks were different in each sector.