Mining companies need `clean technology'

Dewi Anggraeni, Contributor, Melbourne, Australia

We have learned that our fragile environment is under constant threat of pollution from various sources, not least from manufacturers and miners whose toxic chemical waste enters the waterways as well as the air we breathe.

Fortunately awareness of cleaner production methods is increasing. And as this increasing concern for maintaining the health of our environment becomes more widespread, the less scrupulous manufacturing and mining companies who are still polluting the environment become more exposed.

So if you are a manufacturer or a miner trying to find an economical waste treatment process, you are no doubt looking at ways of minimizing your toxic waste or looking for the best waste treatment technologies.

Most of the polluters, it seems, are not setting out to pollute. They are, rather, just irresponsibly negligent. When they regard the costs of cleaner production as an added burden instead of part of running a company, the temptation to disregard that obligation will be hard to resist.

An Australian company based in Queensland, Australian Mining Investment Limited (AUM), claims it has successfully developed a technology that can reduce the cost of processing, and at the same time eliminate components of the waste that pollutes waterways.

Named AUM Column Technology by the company, this method of processing replaces the conventional solvent extraction processes called SX/EW (solvent extraction/electro winning) for extracting copper and nickel from solution.

AUM chief executive Wayne McCrae explains that apart from the fact that SX/EW processes are very costly, cumbersome and a known fire hazard because they require large quantities of kerosene, the solvent used to extract the metal is highly toxic.

AUM Column Technology, says McCrae, uses an organic chemical that will not leak out from the column and does not use any kerosene in the process. The result is clean technology that does not pose a fire hazard.

With AUM technology, when the copper is mined it is transferred into a large plastic-lined vat below ground. The copper ore is then crushed to approximately two or three cubic inches and soaked in sulphuric acid. The sulphuric acid dissolves the copper out of the ore, and the solution is pumped into the AUM Column.

The organic solvent in the column extracts the copper, leaving unwanted minerals to be returned to the vat. No leakage of copper or organic solvent occurs. Solvent consumption compares well with the conventional SX/EW plant, which usually consumes between AU$50 and AU$100 worth of organic for every ton of metal produced.

AUM technology eliminates the threat of toxic organo copper wastes, which in the conventional process are usually pumped into waste tailings dams from where they eventually find their way into rivers and other waterways.

The other good news, according to McCrae, is that the cost of installing an AUM Plant is only a fraction of the cost for the available conventional plants.

Ian Fraser, an environmental management consultant and director of Cleaner Production Management Pty Ltd in Melbourne, says that methods of minimizing toxic waste are being developed all the time by various research groups.

He says that if the organic solvent patented by AUM really delivers on its promise, AUM Column Technology will no doubt benefit mining companies who use it, because it costs less and at the same time reduces the environmental burden by reducing the toxicity of the waste that enters the waterways.

McCrae says all tests have shown that the technology works, but AUM is still putting the finishing touches to the process.

"We have entered into a joint-venture agreement with Hall Chadwick Corporate in New South Wales and Kirby International Pty Ltd. And this joint-venture allows for the formation of a special purpose company for the purpose of commercializing AUM's range of mineral production technologies and environmental technologies in the People's Republic of China," said McCrae.