Coalition for Eco-Efficient Comminution (CEEC), a recently established not-for-profit company, describes its mission as to market and raise awareness of relevant research and alternative comminution strategies with the objective of achieving lower process costs and further energy efficiencies in the mining sector. As part of its effort to bring focus to the problem, CEEC has developed a Web-based information portal (www.ceecthefuture.org) which lists a range of key research papers and profiles a number of consultants and researchers who specialize in the field of comminution design.
According to the Australia-based organization, crushing and grinding steps in mineral processing of ores represent a substantial proportion of total energy cost and carbon emission in mining. For some mine sites the energy usage by crushing and grinding processes represents 70% to 90% of total energy consumption. Despite the funding of a significant amount of research undertaken in this area, awareness in the industry of the significant impact of crushing and grinding on costs and energy usage, particularly at board level, is relatively low. Furthermore, the pace of technology transfer is slow, reflecting the high perceived risk associated with change.
Research and improved engineering design has established that a range of improved blasting, crushing and grinding techniques and flow sheets may lower pro-ject costs and carbon footprint. These include relatively straightforward strategies such as removing waste material before size reduction, a better combination of grinding technologies and targeting larger grind sizes where mineralogy allows. The majority of existing comminution circuits feature tumbling mills, SAG/AG and ball mills. The nature of size reduction in such devices is ‘hit and miss’ leading to the generation of excessive mechanical energy and heat—less than 5% of the energy consumed by tumbling mills is used in size reduction.
The comminution phase in mineral processing has been specifically selected for focus because it represents a substantial proportion of total energy cost in mining, said CEEC. The substantial comminution energy input, combined with a growing body of research, represents a major opportunity for beneficial change.