Increasing water pressure in the Great Artesian Basin

Increasing water pressure in the Great Artesian Basin

Water use by Olympic Dam in South Australia has the potential to impact the Great Artesian Basin (GAB) springs and neighbouring pastoral properties.

The water supplied to the Olympic Dam mine, Roxby Downs township, Andamooka township and some local pastoral properties is pumped from two wellfields located within the GAB. The GAB is one of the largest underground water reservoirs in the world, underlying 1.7 million square kilometres of central Australia (approximately 22 per cent of the continent). Current and historical utilisation of this water resource has been critical for the development of much of central Australia by industry and agriculture.

However, extraction of water for industrial and agricultural use reduces aquifer water pressure which can lead to reduced pressure for pastoral wells and lower environmental flows to artesian springs that arise from the GAB, to which local Indigenous groups have a recognised connection. Reduced aquifer water pressure also has the potential to constrain production at Olympic Dam if not appropriately managed.

BHP works to reduce the impact on aquifer pressure through onsite and offsite means. At Olympic Dam, we are continually working to improve the efficiency of water use in all aspects of our operations. Offsite, Olympic Dam has been participating in programs to reduce the amount of water going to waste across the region (specifically, waste as a result of uncontrolled flow from bores in the GAB into open bore drains – a pastoral practice that commenced in the early 1900s).

In 2000, the Australian Government introduced the Great Artesian Basin Sustainability Initiative (GABSI) to cap, repair and restore uncontrolled bores and recover pressure across the entire GAB. Olympic Dam has, both unilaterally and in conjunction with GABSI, approached landowners in the vicinity of BHP’s wellfield areas and offered to cover the costs of decommissioning or replacing bores, or provide reticulation systems to remove bore drains and reduce the flow of water.

GABSI and Olympic Dam’s supporting activities have significantly offset the impact on water pressures in the vicinity of the GAB springs. Olympic Dam has contributed to approximately 235,000 megalitres in cumulative water savings for the region since 1999.