A guide to leading practice sustainable development in mining

Beyond the operation, poor reputation for water management can contribute
to loss of investment attractiveness, destruction of shareholder value, access to
other resources (water, ore, land), licence to operate and difficulties in the area of
attraction and retention of key staff. These strategic risks may be far more financially
damaging than those at the operational level. The Bulga mine is an example of a
company managing these risks.
Xstrata Coal New South Wales’s open cut Bulga mine has traditionally been
reliant upon the local Hunter River to extract water by licence for use in the
washing and mining processes.
Following severe dry weather experienced in 2007, the mine identified water
security as a risk which needed to be addressed. In response, the mine
investigated new opportunities to decrease its reliance upon the Hunter,
increase water security and more effectively use stored water on site. As a
result, a series of new initiatives were put in place to improve onsite water
management and implement more effective conservation procedures. Actions
taken included:
Long and short term water balance models - Xstrata Coal NSW
engaged water management consultants to develop short and long
term water balance models to assist in making day to day decisions
about water transfers, discharges and licence allocations (short-term)
and to simulate mine supply, demand and storage requirements over
the life of the mine under various climatic scenarios (long-term).
The long term water balance model identified the benefits and
desirable size of additional on-site water storage, which would
substantially reduce the requirement for Hunter River water and the
need to discharge mine water off site. In response, a 3,000ML dam
is currently being constructed to better capture mine spoil runoff
to be used in the washing process and for dust suppression.
Tailings Flocculation - A secondary flocculation system was installed
within Bulga’s tailings system, allowing water to be released from
the coal tailings faster and thereby increasing the amount of
water available for recycling. This action also consolidated Bulga’s
tailings faster, providing a more stable surface for rehabilitation.
Underground Raw Water Reuse - Historically, approximately 35
megalitres of Hunter River water was used per month for dust
suppression at the Bulga open cut and wash down and cooling in the
Bulga underground (Beltana) longwall and development mining.
A GUIDE TO LEADING PRACTICE SUSTAINABLE DEVELOPMENT IN MINING 121