CSIRO scientists are developing a new breed of fast sensors for use in the online analysis and identification of mineral ores.

Sorting ore particles before processing can cut downstream costs, limit environmental harm by reducing mine wastes and improve ore quality and mineral recovery.

These fast sensors will service a renewed industry need for fast ore sorting processes. CSIRO is now seeking interest for trial developments of the sensors.

"As higher grade ore reserves are gradually depleted or become harder to locate, mining companies are having to mine lower-grade ore," says Dr Nick Cutmore, project leader of the CSIRO team developing the sensors.

"These lower grades therefore need to be refined to a higher grade but in an economic fashion. By rejecting the lowest-grade material before milling, ore sorting can enable lower-grade ores to be upgraded. This increases the net output of the valuable mineral per tonne of ore processed," he says.

"Existing ore-sorting systems are largely based on sensors that sort according to colour or intensity of reflected light, which severely limits the range of ores they can sort."

"We are researching ways to optimise the use of sensing technologies such as lasers, microwaves, x-rays and neutron sensors, as well as new approaches to signal processing. These technologies will be used online for real time automation and control of sorting base metal ores like tin, lead/zinc, nickel and copper."

Dr Cutmore says mining industries are being driven by social and regulatory pressure to improve environmental performance.

"Sorting lower-grade ore before the milling process has environmental benefits in reducing the amount of mine-tailings. If the sorting is done near the mine face then the coarse reject material, which is largely virgin rock, can remain at the mine."

As milling is the biggest consumer of energy in the mining process, there are also significant energy savings to be made by milling only the refined, higher-grade material.

A number of Australian companies have led the industry in the development of automated sorters that can sort ore particles at rates of 10-100 tonnes per hour. The new sensors being developed by CSIRO can be incorporated into these existing mechanical sorters.

"We are developing fast sensors that, in the time frame of milliseconds, will decide what the grade of the ore particle is and allow the machine to decide how to sort it," says Dr Cutmore.

"Ore sorting has always been, and still is, a niche mineral processing technology that requires optimisation for each application. CSIRO is working with companies to further develop the technologies so they will be suited to their ore."

"The team from CSIRO Minerals has a reputation dating back more than 30 years for developing technologies for the on-line analysis of bulk ores, including elemental and mineralogical composition, mass flow and particle size."

The ore sorting team is just one of many research teams in CSIRO that are working on mineral analysis technologies.