A quiet revolution in comminution

This morning I welcomed around 250 delegates from 30 countries to Comminution ’12.

Much has happened in comminution over the past 23 years, since the 1st International Symposium in Cornwall in 1989. Three years prior to that I was involved with a 2-week NATO Advanced Study Institute, held in Falmouth. The purpose of this meeting was to bring people together to discuss the status and future of mineral processing as ores became ever more complex and refractory. Mineral Processing at a Crossroads looked in depth at new methods which were going to revolutionise mineral processing, such as super-conducting magnetic separation and electrolytic flotation, but comminution hardly had a mention!

This was because for most of last century there had been little development in comminution machines and circuits, cone crushing being followed by ball milling, rod mills sometimes acting as tertiary crushers (it is interesting to note that there is no mention of rod mills in this week's programme, suggesting that they might now have gone the way of the stamp mill?).  Comminution was well known to be energy intensive and inefficient, but there was little that could be done about it.

In the latter part of the century, however, there was a quiet revolution. Autogenous and semi-autogenous milling became more prominent, and then high-pressure grinding rolls began to play an ever increasing role, as did stirred mills, the latter allowing the exploitation of ultra-fine grained ores which had hitherto been impossible to economically treat.

This revolution continues, so that comminution circuits today are very much different to those of the mid-20th century with their parallel lines of small ball mill-cyclones. People are still very much aware of the energy consumed in comminution, but are now prepared to really do something about it. Since the last conference in 2010, the Coalition for Eco-Comminution has been formed, a not-for-profit company. Its mission is 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. Malcolm Powell will be telling us more about the CEEC later in the week, and in the first keynote lecture this morning Chris Rule of Anglo American Platinum, discussed, via a PGM perspective, how flowsheets might further evolve over the next few years.

So it is not surprising that this conference, the 8th in the series of International Comminution Symposia, is the biggest yet. There were 166 delegates two years ago at Comminution ‘10, then the largest turnout in the series. This year we have a record number of sponsors, 18 from all around the globe.

My full report on the conference will be published on the blog at the end of next week.