The Olympic Dam mining and processing operations currently use
on average 35 megalitres per day of water. This water is piped
from two wellfields in the Great Artesian Basin.
The proposed expansion may require up to an additional
125 megalitres per day.
To meet that potential demand BHP Billiton examined a range of
water supply options including:
• additional water from the Great Artesian Basin
• water from local saline aquifers
• the purchase of River Murray water licenses
• partially treated effluent from Adelaide.
BHP Billiton has now focused on developing a coastal
desalination plant in the Upper Spencer Gulf as its preferred
primary water supply option.
Alternative water supply options were not progressed because of
environmental impacts, long-term sustainability and security of
supply issues, cost, or a combination of those factors. For
example, the use of partially treated effluent from Adelaide was not
regarded as sustainable because ultimately the water could be
required by metropolitan Adelaide if climate change continues to
impact on existing water supplies. It was also considered too
costly as it would require the construction of a 600 km pipeline
and water treatment plant to render the water suitable for industrial
and potable use.
Point Lowly, 15 km north east of Whyalla, is the preferred location
for the desalination plant as it offers both deep water and strong
currents, which aid dispersion of seawater concentrate. Alternative
locations in the Upper Spencer Gulf and Eyre Peninsula have been
investigated but are inferior to the proposed site in these respects.
The site of the plant would be approximately 18 hectares.
Point Lowly’s proximity to SA Water’s major water distribution
network also offers the opportunity to expand the plant and produce
water for the communities of the Upper Spencer Gulf and Eyre
Peninsula, which currently face long term water supply constraints.
To explore this opportunity the South Australian Government has
signed a Memorandum of Understanding with BHP Billiton to jointly
study the desalination option to meet both the needs of the future
mine and to supply the communities of the Upper Spencer Gulf and
Eyre Peninsula.
BHP Billiton is investigating:
- the best location for the desalination intake pipeline and the
discharge outlet
- the potential short and long term impact of concentrate discharge,
if any
- the sensitivity of marine life, such as the Giant Cuttlefish and the
Western King Prawn, to various salinity levels.
The results of these studies will be presented in the EIS which is
being prepared for the Expansion Project. This EIS will be available
to the public for review and comment before it and a response
document addressing public comment is submitted to the Federal
and State Governments for approval to proceed with the
desalination plant and other elements of the project.
 Seawater desalination removes salts and other material from seawater
to produce high quality water for industrial and domestic use.
The proposed desalination process is “reverse osmosis” where
seawater is pumped, under pressure, through a membrane which
filters the seawater.
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The proposed desalination plant would draw around 290 megalitres of
seawater per day from the Upper Spencer Gulf via an intake pipeline.