A guide to leading practice sustainable development in mining

Site water use
Water is used for numerous tasks across the mine site and will depend on the type of
operation. Leading practice mines minimise water use while maximising water reuse.
Water reuse is defined in a number of ways and is also often used interchangeably
with water recycling. Water reuse minimises demand for water from off site and
thereby focuses attention on leading management practices within the site. Leading
operations generally have better control over water releases because reuse is carried
out extensively and consistently.
Olympic Dam recognises that the responsible use of Great Artesian Basin (GAB)
water is essential to protect the environmental values of the GAB springs, a key
concern for some of its stakeholders. The mine monitors the rate at which it extracts
water from the two wellfields to ensure that it is always within prescribed limits and
that adverse impacts are not occurring. The ongoing challenge is to continue to meet
these limits while providing the opportunity to optimise plant production rates. The
project confirmed the importance of regular inspection, testing and calibration of
process indicators. Significant water savings have been identified and implemented
in the three key production areas (see LP Water p.57).
Figure 4.23 – Main shaft at Olympic Dam
Re-injection into watercourses
Re-injection is the practice of replacing groundwater into the same or a nearby
aquifer. It can be achieved using engineering infrastructure and/or passive reinfiltration
via local water courses. In some circumstances it is preferable to releasing
water into surface water systems and/or relying on evaporation. Re-injection is
considered water diversion when the receiving aquifer is within the lease boundary
and as an output when it is outside the lease boundary.
A GUIDE TO LEADING PRACTICE SUSTAINABLE DEVELOPMENT IN MINING 127