Wednesday, 27 July 2011

Base Metals '11 Conference Diary

The 6th SAIMM Base Metals Conference was held from 18-22 July 2011 at the Hans Merensky Hotel, at Phalaborwa in the Limpopo province of South Africa (see yesterday's posting).

The aim of the conference was to explore the factors which will maintain and contribute to the growth of the base metals momentum in Africa in terms of geology, mining and metallurgy. The conference also focused on the value of mineralogy and energy saving innovations in the base metals industry.

As always, I invite comments from those who attended the meeting. My emphasis will be on the mineral processing aspects of the conference.

Monday 18th July

Despite last evening's excellent wine reception, we arose with the sun this morning to the sight of impala grazing on the golf course which runs by our room. This compensated, to some extent, for the lack of adequate internet facilities at this otherwise splendid hotel.

The conference was opened by Paul Fouche, the chairman of the organising committee, and Operations Manager of Exxaro-Zincor, who then introduced Rodney Jones, of Mintek, who spoke on behalf of the President of the SAIMM.

Rodney welcomed the 180 delegates, representing 14 countries, although over 80% are from South Africa, mainly from industry and manufacturing. Rodney summarised the history of the SAIMM and of these conferences, which commenced in 2001 in Victoria Falls (Zimbabwe) and have been held every 2 years, in Sun City (South Africa), Kitwe (Zambia), Swakopmund and Kasane (Botswana).

The first presentation was made by Wilhelm van Rooyen, the Chief Operating Officer of nearby Palabora Mining Company, who spoke of the future opportunities and challenges for copper and by-product magnetite and vermiculite production on this major South African copper producer. This provided an excellent background in anticipation of Thursday's visit to the mine.

Presentations today included papers on the passivation of sulphides in oxidative leaching, autogenous milling commissioning at Nkomati Nickel and an introduction to the Rados XRF ore sorter, which was developed in Russia.

The revival of uranium as a valued commodity has prompted a drive to identify the most cost-effective processing routes for the recovery of uranium from low-grade ores or wastes. An interesting paper from Mintek described the recovery of uranium from dense slurries via resin-in-pulp.

Another paper from Mintek discussed trials of the Xanthoprobe, an automated online instrument developed by Mintek for the measurement of residual xanthate concentration directly from flotation concentrate cells. It has been installed at the Eland Platinum PGM concentrator since March 2010 to establish the long-term robustness and measurement accuracy of the instrument in an industrial environment.

The conference has a small exhibition in the coffee break-out area, and exhibitors include CiDRA Mineral Processing, FLSmidth and Outotec, sponsors of MEI's Flotation '11 in November.

The day finished with a late afternoon game drive into nearby Kruger National Park, which provided a great opportunity to meet new people and see some of the African wildlife. Eighteen safari vehicles, each carrying 10 delegates and partners, made their separate ways in the park before finally meeting by a large kopje for an evening bush-braai under a star-lit African sky.

Tuesday 19th July
Today's sessions began with a keynote lecture from Anglo American on the need for innovation in base metal processing. This was followed by a keynote from Rolf Sandenberg, of University of Pretoria, on developments in zinc hydro and electrometallurgy.

Ore sorting has come to the fore again recently, with the development of high speed sensors and computers. One of the leading players is CommodasUltrasort, who presented a paper on the use of sorters to remove hard pebbles and recover copper bearing rocks from the Palabora autogenous milling circuit.

Energy consumption is often described as a primary contributor to the life cycle operational cost for flotation. However, it was shown by FLSmidth, USA, that effective use of an increase in energy can lead to higher concentrate recoveries, thus increasing overall profits. The paper illustrated the benefits attained when an economic evaluation considers both energy and concentrate product.

Other papers this morning discussed the recovery of copper and cobalt from tailings, and the use of sulphuric acid in the mineral sands industry as a chemical mechanism for iron removal.

Cobalt is produced mainly as a by-product of other major metal extraction processes, mainly copper and nickel, and in recent decades the nickel industry has been the major source of cobalt. Now, however, the Democratic Republic of Congo's copper-cobalt production is becoming important again after a 20 year period of decline. An afternoon paper from Bateman Engineering highlighted the developments that have made the increased production possible, and reviewed the status of several technologies available for cobalt production flowsheets, particulary electrowinning.

A paper from IBC Advanced Technologies, USA, reviewed the selective separations of cobalt, uranium, zinc, nickel and associated contaminants from various process streams.

Mineral processing has some unique and demanding flow measurement requirements, which are not always adequately met by traditional flowmeter technologies such as electromagnetic flowmeters or Doppler flowmeters. A paper from CiDRA Minerals Processing, Canada, described improved flow and flotation monitoring for process efficiency improvements through new technology utilizing non-invasive passive arrays.

The afternoon session finished early to allow time for 'afternoon activities' which were mainly golf related. Part of the hotel complex contains the Hans Merensky Country Club, a golf course of renowned standard. Being a firm believer that golf clubs spoil a good walk, I took a long walk around the course perimeter, which turned out to be a fascinating game trail. I came within a few metres of two giraffe, spotted warthog (and delegates) digging up the fairways and greens, and saw very large herds of impala.

In the evening a cocktail function sponsored by Nalco (one of the Flotation '11 sponsors) preceded the gala dinner. Good food, good company, with entertainment supplied by a local Shangani group.

Wednesday 20th July
The final day of the conference began with a keynote lecture from R.T. White of the International Zinc Association of Southern Africa. The zinc industry in Southern Africa is undergoing changes with the announcement of the disposal of the Anglo Base Metals business to Vedanta Resources, and the paper outlined the structure and opportunities in the zinc market in South and Southern Africa.

There were a number of good, practical hydrometallurgy papers today. A presentation from the University of British Columbia, Canada, compared various iminodiacetic chelating ion exchange resins for nickel recovery. In particular, the possibility of using these resins for base metal resin-in-pulp applications has become topical in recent years, and resin manufacturers have developed new large bead products for this potential market.

Solvent extraction is now a well established part of copper hydrometallurgical extraction, and a paper from Kansanshi in Zambia discussed the development of effective solvent extraction control.

Bioleaching for the extraction of base metals from sulphide ores and concentrates has been under development for several decades, and is finding increasing commercial application. Heap bioleaching of secondary copper sulphides was pioneered in Chile for diminishing acid-soluble oxide ore resources. The technology was rapidly developed in both Australia and Chile through the recognition that oxygen, not acid, is the principal reagent in the process. Forced aeration is now used in all these operations. The engineering design and operational control of sulphide heap bioleaching operations have developed to the point where the process can be applied for the treatment of primary copper sulphide ores, where heat retention in the heap is the critical requirement to promote the oxidation of chalcopyrite. Commercial implementation is now underway in the Middle East and Chile (see also What is the future for heap bioleaching?). Mintek has been a leading developer of bioleaching technologies for over 25 years, and their paper reviewed the state of play in base metal leaching, including the choice between tank and heap bioleaching, microbiology and many other factors.

High-pressure grinding roll technology is a major theme of next year's MEI conference, Comminution '12. HPGR technology is being applied in an increasingly diverse range of applications, predominantly for iron, gold and diamonds. KHD Humboldt Wedag is the major manufacturer of HPGRs and their presentation summarised some of the features and experiences in recent applications in the treatment of copper ore, coarse iron ore, and gold ore.

In closing the conference, chairman Paul Fouche advised that a decision on the venue for Base Metals '13 would soon be made, the main contenders being either Tanzania or Zambia. Details will be published on MEI Online as soon as available.

The SAIMM's Raymond, Caron and Jacqui
This has been my first Base Metals experience, and very enjoyable and rewarding it has been. The Organising Committee, chaired by Paul Fouche, and the SAIMM team, of Raymond van der Berg, Jacqui van der Westhuizen and Caron Lance, deserve our congratulations for organising such a splendid event.

The Proceedings of the conference is available in hard back and CD formats (ISBN 978-1-920410-20-9) and details can be obtained from Raymond van der Berg ( or

Relaxing with delegates in the hotel bar after the conference

Thursday 21st July
After a memorable last few days, the morning visit to Palabora Mining Company was a huge disappointment. Three hours of security, and health and safety inductions left little time to visit the operations. I chose the surface operations tour, and we briefly looked at the giant autogenous mills, passed by the copper flotation plant, the magnetite processing and vermiculite processing plants, and had a brief look at the smelter before ending with a walk through the anode refinery. All in all a huge anticlimax to a rewarding week. Having said that, the concentrator and smelter personnel were very informative and obliging and I would like to thank them for their efforts under trying circumstances.

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