By Chelsea Wallis
Jun. 10, 2013 – Mining IQ

The plan to update the Geocentric Datum of Australia 1994 (GDA94) may have an enormous impact on the mining sector in Australia as soon as 2015, according to the Intergovernmental Committee on Surveying and Mapping (ICSM).

Within the decade the Australian on the street will be able to access GNSS data in real time with a positioning accuracy within 10 cm or better. GPS around the world is catching up to the mobile, real-time revolution with the deployment of GLONASS in Russia, and updates to Compass in China and Europe’s Galileo.

In comparison, GDA94 is out of date – and after 19 years and 1.8 metres, it’s starting to show.

The Australian system was last calibrated to the International Terrestrial Reference Frame in 1994. It hasn’t made much of a difference to the big picture despite Australia shifting about 7 cm per year to the Northeast along tectonic movement.

ICSM hopes to have a readjustment in place by 2015, incorporating data from the Commonwealth, state and territory governments into a new system capable of positioning anywhere in Australia with a precision around 2 cm in real time – with a new reference epoch of 2020.

“The economic analysis suggests that this precision positioning capability will contribute 2.1 per cent to Australia’s GDP, and that will be in things like automated mining systems,” says Dr John Dawson of Geoscience Australia’s National Geospatial Reference Systems Earth Monitoring and Hazards Group.

In the long term, Dr Dawson says his team plans to transition the Australian geospatial community (with the help of updated international satellite systems) to a dynamic datum – where the coordinates move on a continual basis to reflect real motion – before the 2020 data goes the way of GDA94.

“In terms of the mining industry, this capability will really improve productivity,” Dr Dawson predicts. “While mining companies are already progressing towards automated mine site and transportation systems, we think as soon as 2020 we’ll see intelligent transport systems that may well be driverless in air, rail, road and sea.”

In fact, new research by Australia National University shows Australia isn’t the only one realising the reality of precise, real-time positioning. Data shows major earthquakes across the globe since 2000 have skewed the position of GPS sites, sometimes thousands of kilometres from the quake event.

In his journal paper, Dr Paul Tregoning, senior fellow at ANU, says there is a 0.1-0.3 mm per year disruption worldwide if movements due to earthquakes registering a moment magnitude over 8 are not taken into account. The 2004 Sumatra-Andaman earthquake, for example, displaced the GPS site in Darwin by around 2 mm, the 2004 Macquarie Ridge earthquake displaced a Hobart site by around 10 mm and the 2007 Solomon Islands earthquake moved Townsville by around 1.7 mm.

This can affect sea level readings and tectonic measurements, but Australia, along with the North Atlantic and Arctic regions, was found to be one of the least affected regions. So really, there’s little impact from earthquakes on determining mining exploration.

“In mining, it depends on your accuracy requirements and often mining GPS positions are derived relative to a local base station,” Dr Tregoning says.

“There are a variety of techniques for establishing the correct reference point in exploration,” agrees Joshua Allsop, Mining Business Consultant at Haefeli-Lysnar in Western Australia. “When these are used in conjunction with each other the results will be self-correcting, so there is no concern with seismic contamination if the points are being set up correctly on a new site.”

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