The ability to identify and access sustainable sources of water from deep underground will be critical for developing northern Australia and other arid regions of the country. TIM THWAITES reports
Article from resourceful: Issue 11
Water, critical to life, health and the maintenance of communities, is also essential for the development of mineral, and oil and gas resources. It is simple – no water, no production.
"We've had issues where potential mine development was proceeding and the companies had to delay their programs and do extensive searches to try and come up with a water supply," South Australian Department of Environment, Water and Natural Resources' director for state research coordination, Neil Power, says.
In most of Australia where exploitable mineral deposits occur, particularly in the arid outback, a reliable water supply is typically sourced from groundwater in the top few hundred metres of sediments under the surface, which itself is often buried under a similar depth of the ancient weathered rock known as regolith.
Under CSIRO's Deep Earth imaging Future Science Platform, the research organisation is bringing together the skills and capabilities to peer through the earth and determine with greater certainty where usable sources of water are likely to be.
"For the resources industry, this would reduce up-front costs by developing more effective drilling for groundwater," CSIRO senior principal research scientist, Dirk Mallants, says.
"It could further provide a demonstration of the potential impact on water resources where they are used by neighbouring communities or to sustain precious ecosystems or cultural heritage sites. This is critical to obtaining a licence to operate. In short, it would reduce business risks."
"Governments could develop groundwater management plans with better understanding and more certainty, allowing them to set sustainable extraction rates and limits more precisely, so water resources can be developed to their full potential."
But, better knowledge and understanding of the location of water resources is only part of the story.
It is also important to understand their connectivity, that is, how water flows underground connect with surface water and underground resources.
"If you take water from a bore, how does that affect the spring a couple of kilometres downstream," Dr Mallants says.
This information is also of critical significance in areas where water underpins sustainable economic development, including the development of coal seam or shale gas deposits. And that's where the underground imaging of water meets the much deeper earth imaging of mineral and energy resources (see Exploration El Dorado and Beyond limits in this issue of resourceful).
CSIRO has been developing the use of environmental tracers, natural chemical compounds whose presence and concentration detected across many locations and depths can provide information on the source and age of water and the minerals with which it has come into contact.
Although the initial three-year phase of Deep Earth Imaging has only just begun, CSIRO has been working on projects relevant to the underground detection and description of water resources for some time.
Since 2010, CSIRO has played a leading role in the Facilitating Long-term Outback Water Solutions (FLOWS) program of the Goyder Institute for Water Research, established by the South Australian Government as an independent body to provide expert scientific evidence to support water policy development.
The FLOWS work started with reinterpreting airborne electromagnetic (AEM) data to image ancient watercourses, known as paleochannels, in the north of the state, before moving on to the Eyre Peninsula to reinterpret existing mineral company AEM data. This research has already led to the announcement of a new silver deposit.
Now, a new project is being explored to field test and improve mapping and quantification of groundwater availability in the Musgrave Province in South Australia's north, a priority area for mineral exploration. It will utilise new AEM surveys flown to expand the data available.
In Western Australia, the developed capabilities will be relevant to managing large groundwater resources such as in the Perth Basin, the main source of water supply for Perth and its industries.
"For the north of Australia," leader of CSIRO's water in the resources sector group, Olga Barron says, "hydrogeological assessment to support regional development is critical."