Scientists at the Australian Nuclear Science and Technology Organistion (ANSTO) based at Lucas Heights are leading the world in the development of technology to measure and model the potentially environmentally hazardous impacts of sulfide in waste rock typically associated with large scale open cut mining operations.
ANSTO is an agency of the Commonwealth Government, providing services to government, industry, the research and development community and the wider community in general.
The group of scientists who are attached to Environment ANSTO have developed an instrument called an Automatic Oxygen Analysiser (AOA) that can measure oxygen concentrations in waste rock dumps, ore stockpiles and in process ore heaps for the optimisation of operational conditions.
The technique is a world first in automated measurement, and a unique Australian invention that will go a
long way towards addressing global environmental problems. Mine waste rock dumps are growing year by year around the world with some of the largest in the order of hundreds of millions of tonnes. One mine in Indonesia, for example, dumps a third of a million tonnes of waste rock each day.
A report written in 1997 by Dr John Harries, a senior member of ANSTO Environment, on the results of a survey conducted of 317 mines, found that 54 sites were found to be managing significant amounts of potentially acid generating waste and a further 62 sites were managing some potentially acid generating wastes.
With inefficient waste rock management typically using soil covers, such dumps can become exposed to water and oxygen that in turn produce metal sulfates, which can cause serious harm to the environment.
The measurement technique, developed by ANSTO, involves drilling a hole through a waste rock dump and using an AOA instrument that pumps up gas samples from sample tubes, allowing the measurement of oxygen concentration as a function of depth. Oxidation processes have a direct relationship with the levels of toxic effluent that can be generated from mine site waste rock dumps.
The AOA instrument is highly portable. Housed in a weatherproof case not much bigger than a typical suitcase, it weighs in at approximately 15 kg. This makes it a highly portable piece of environmental field equipment that can easily be taken to almost any location around the globe.
The information gathered from this technique allows mining companies to develop a pro-active approach to pollution control and study the effectiveness of the soil covers used to reduce waste rock dump interaction with physical processes. In many cases waste rock dumps are covered by a clay-based composite to reduce water infiltration rates and in some cases oxygen flux, but over time toxic effluent often develops.
The AOA also has the potential to be used for wider applications including measuring oxidation rates in landfills and in municipal and domestic rubbish tips. This technology could be an invaluable piece of equipment for environmental officers employed by local councils for performance monitoring.
The technology has been developed by a 23-strong team of physicists, chemists, biologists, mathematicians, engineers and geologists under the auspices of an enterprise within ANSTO called Sulfide Solutions, which is managed by General Manager Bruce McDonald.
The technology had its origins in work that began more than 25 years ago in rehabilitating worked-out uranium mine sites in the Northern Territory.
Sulfide Solutions has already sold the AOA technology to a number of mining companies both within Australia and internationally and has leased the apparatus to a number of local and international mine sites for short-term assignments.
Sulfide Solutions is using this innovative measuring device in a number of countries including Indonesia, South America in a uranium mine closure, Europe in base metal and uranium mine closures and North America. It is also used here in Australia in the Bowen Basin coalfields in Queensland and in NSW hard rock mining operations and will be used shortly in Western Australia.
This type of research and the resultant breakthrough in technological advancement is typical of the work done by ANSTO scientists in delivering the benefits of nuclear science and technology to Australian and international
industry and the community.
With the development of the ANSTO Technology complex, technology companies are now taking advantage of this on-site expertise and access to worldclass scientific facilities.