Drinks with two well known metallurgists

It was good to reminisce over a few beers by Falmouth's inner harbour on Monday evening, with two old friends, Dave Dew and Frank Crundwell.

Dave, me, Frank

Frank I first met in Falmouth in 1996 when he represented the University of the Witwatersrand at Biotech '96. He is in the UK this week to set up a metallurgical consultancy, as a sister company to his South African company CM-Solutions, which he hopes to operate from London. He is down in Cornwall to present a seminar today at the Camborne School of Mines.

Biotech '96. Left to right are Jim Watson (UK), me, John Wells (Chile), Barbara, Sue Harrison (South Africa),
Jan Cilliers (UK), Frank Crundwell (South Africa) and Andy Sarosi (UK)

Dave I have known for 40 years. He was in the Camborne School of Mines class of '79, one of the first graduates in mineral processing. In 1978 he was one of a party of vacation students from various British universities whose projects I supervised in Anglo American mines in South Africa.

British mineral processing students in Johannesburg, 1978. Dave Dew is the one standing

After graduating from CSM Dave stayed on to complete a PhD, then returned to South Africa in 1983, where he had great success with Gencor Ltd, and became a leading player in the relatively new field of biohydrometallurgy. Initially he was involved in development projects related to gold recovery by carbon-in-pulp and carbon-in-leach technology, which was rapidly taking over from the conventional cyanidation for treatment of gold ores.

In 1990, as Principal Research Metallurgist, he joined the project team responsible for development of the BIOX™ Process. He took a lead role in the improvement and design of the bioleach reactors reducing power costs and establishing a methodology for pilot testing and commercial plant design. The technology was applied in a number of new operations notably Sao Bento in Brazil, Wiluna in Australia and Ashanti Goldfields in Ghana.

When in 1998 the assets of Gencor excluding platinum, were transferred to Billiton, Dave continued with the development of bioleaching technology with a focus on the treatment of nickel and copper sulfide concentrates. He was appointed Manager Process Development responsible for leading research in this area, resulting in the successful pilot scale demonstration of the BioNIC™ Process for treatment of an Australian nickel sulfide concentrate and the demonstration of the BioCOP™ Process in 2000 under the Alliance Copper Joint Venture with Codelco, producing 20 000 tpa copper from chalcopyrite concentrates contaminated with arsenic.

In 2001 Billiton merged with BHP to become BHP Billiton and Dave was appointed as Global Technology Manager at the Johannesburg Technology Centre primarily responsible for technology development for the Base Metals division. During the period from 2001 to 2009 the centre focused on the development of bioheap leaching and chemical heap leaching technology for treatment of low grade primary copper sulfide ores. The bioleaching technology for high temperature leaching of low grade chalcopyrite ore was tested in a 250 000 pilot test heap at the Escondida Mine in Chile over the period 2005-2008. In 2009 the Technology group of BHP Billiton was restructured and the research laboratories in Johannesburg were closed and key activities related to development of heap leaching technology were transferred to a new, purpose built facility at the Escondida Mine, Chile.

Dave became an independent consultant in 2012 and formed his own company, Dewality Consultants Ltd, which he operates from his home in Cornwall. He is still very much involved with Chile, specialising in bioheap leaching of sulphides. He is also an honorary associate of CSM and advises on research projects, including rare earth resources, their security of supply and methods of concentration.

Dave and Frank also go back a long way, having first met in South Africa in 1990 when Frank was a young research officer at Wits, working on a project funded by Gencor. I will be catching up with Frank at Flotation '17 in November where he will be presenting a paper on the mechanism of the flotation of soluble and semi-soluble salts. Dave I am still trying to persuade to take some time out of his very busy schedule to present a keynote lecture at Biohydromet '18 next June in Namibia!

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