Bacterial Leaching
AMMTEC is pleased to be able to offer, in association with Pacific Ore Technologies, advanced bacterial leaching test facilities covering bench scale testwork through to continuous pilot plant campaigns. Pacific Ore Technology's staff have extensive experience in all areas of bioleaching through to the design, construction, commissioning and operation of full scale bacterial leach plants.
Pacific Ore Technologies - The Company
Pacific Ore Technologies specialises in the development of leaching, solvent extraction and electro-winning solutions to the mining industry.
Bacterial leaching is rapidly developing into a major metallurgical unit operation which will not only transform the economics of known low grade ores but, with the ever increasing environmental demand on pyrometallurgical operations, has the potential to replace the majority of the world's roasting and smelting operations. Pacific Ore Technologies have developed this technology further, adapting it to the treatment of base metal sulphide ores in which the metal values are leached into solution via bacterially assisted chemical reactions.
The strength of Pacific Ore Technologies lies in the depth of experience of it's senior managers Simon Purkiss and Colin Hunter.
Simon graduated in 1980 with a BSc Hons degree in Mineral Engineering from Birmingham University before joining Impala Platinum Ltd. in South Africa. Simon was appointed concentrator manager in 1989. In 1993, after the successful completion of an MBA he was employed by Gencor as an assistant consulting metallurgist. In 1994 he was appointed as commercial manager for Gencor Minerals Technology where he became heavily involved in the development and marketing of Gencor's BioNic® process. He left Gencor the following year to become Managing Director of Osmium Holdings where again, this time in league with Colin Hunter, he became involved in the development of base metal bio-leaching processes. Simon brings to Pacific Ore Technologies extensive precious and base metal experience coupled with a substantial design, operational and development management track record.
Colin graduated from the University of Manchester with a BSc Hons degree in Metallurgy and went on to be awarded a PhD from Brunel University in 1985 for his work on froth flotation of sulphide minerals. He moved to South Africa and worked for Impala Platinum Ltd. in Rustenburg for three years before joining Gencor Process Research where he stayed until 1993, rising to the post of head of minerals engineering. During his time with Gencor Colin became involved with bio-leaching and later went to Ghana as an employee of Ashanti Goldfields Corporation to commission and run the Sansu refractory gold bio-leaching plant which is still the largest of its kind in the world. In 1995 he joined Simon Purkiss as technical manager with the Osmium Group where he developed bio-leach process and went on to develop bio-leach processes for chalcopyrite, lead, zinc and other sulphide mineral systems. Colin brings to Pacific Ore Technologies a wealth of technical, design, operational and managerial expertise.
AMMTEC and Pacific Ore Technologies
For many years the Pacific Ore Technologies team has had close ties with the Research and Productivity Council laboratories of New Brunswick, Canada, where most of the developmental work to date has been performed.
AMMTEC has entered into an agreement with Pacific Ore Technologies to carry out all of their Southern Hemisphere testwork with the Research and Productivity Council laboratories continuing to be responsible for testwork in the Northern Hemisphere.
AMMTEC brings to Pacific Ore Technologies an Internationally recognised and respected testing facility with extensive experience in bio-leaching.
Why Should Clients Look Closely at Pacific Ore Technologies?
It is AMMTEC's belief that Pacific Ore Technologies are significantly ahead of the competition in the field of bacterial leaching. They have developed their leach processes using there own mesophilic and thermophilic bacteria, capable of operating at temperatures up to and in excess of 60°C. This brings about a significant improvement in the kinetics and thereby reduces capital and operating costs.
The superiority of Pacific Ore Technologies is evident in the response of the notoriously hard to leach mineral, chalcopyrite, to its process. Other providers of bacterial oxidation systems can seldom achieve copper dissolution in excess of 60% from chalcopyrite ores, and even this only after prohibitively long leach times or after ultra fine grinding. The chalcopyrite concentrates that have been tested to date using the Pacific Ore Technologies process have all yielded essentially complete copper dissolution in comparatively short times.
There is a huge potential for this technology in the treatment of chalcopyrite rich, copper-gold ores. Bacterial leaching would remove copper from the ore leaving behind a gold concentrate which would be treated in a conventional cyanide leach. In this way the full value of the copper and gold is realised by the deposit holder. Currently, depending on the values involved, traditional methods do not give the deposit holder the full value of the gold credits. Realisation of these credits is also considerably quicker via the bacterial leaching route.
Further, where concentrate production is problematical, heap leaching may provide a viable alternative. Chalcopyrite heap leaching would be of particular interest to existing mines treating oxide or supergene copper deposits by conventional heap leaching methods, where the deposit is underlain by fresh sulphide copper.
There is potential for bacterial leaching in the treatment of copper-molybdenum ores where Pacific Ore Technologies have developed a technique for removing unwanted copper from the molybdenum concentrate.
In nickel bacterial leaching Pacific Ore Technologies has developed a flexible process capable of treating both high and low grade feed stocks by either tank or heap leaching. The Gencor BioNIC® nickel leaching process is limited to relatively high grade feed stocks. The potential for the Pacific Ore Technologies process lies in the treatment of low grade ores, ores that do not concentrate well and remote ores where high transport costs reduce the economics of the deposit. Bacterial leaching would liberate the nickel into solution on site where it can be turned into finished metal with no threat to the environment. There are deposits that, although they upgrade well, contain high levels of arsenic and are therefore unacceptable as feed to most smelters. Bacterial leaching would take the arsenic into solution along with the nickel and precipitate it as a safe and environmentally acceptable compound.
Apart from chalcopyrite associated copper/gold, copper/molybdenum, copper/nickel ores the technology is also applicable to complex lead/zinc ores where the less nobel zinc mineral sphalerite can be leached from a bulk concentrate, for direct electrowinning to zinc metal, leaving behind a high grade lead concentrate. This is particularly important where the metals are in a finely disseminated form and the normal differential flotation process can not produce sufficiently clean concentrates. Where there is an assemblage of sulphide minerals, at least one of which is capable of being oxidised to a soluble sulphate, then there is scope for the development of a bio-leaching process. Mineral deposits have been identified, and are continually being identified, that cannot be treated by conventional metallurgical means. Ores with complex metallurgy that can not be separated into saleable concentrates, or deposits which contain impurities such as arsenic or mercury making the concentrates unsaleable, are suitable applications for Pacific Ore Technologies bacterial leach processes.