Drinking-quality water is piped some 600km from Perth to the Goldfields area. The use of this limited resource is not appropriate for the large quantities required in the processing of gold ore. Instead, KCGM uses the saline and sometimes hypersaline groundwater of the goldfields for mineral processing.

KCGM uses about 12,000 megalitres of water each year. About 17% is potable water obtained from the Kalgoorlie water supply system and the remainder is saline obtained from groundwater and water recycled and recovered from operations. The total dissolved solids content of the naturally occurring saline waters ranges from about 30,000 to about 200,000 milligrams per litre (sea water has about 35,000 to 40,000 milligrams per litre of total dissolved solids).

KCGM uses this saline groundwater in its mills and plants and also to transport tailings. Groundwater protection and management measures are important at the borefields, in the pipelines and at the tailings storage facilities.

Pipelines are constructed of high-density polyethylene laid within earthen bunds with “catch” pits located at low points along the pipelines. If a pipe bursts the saline water is contained in the bunds and catch pits, preventing the salt from contaminating surrounding soil and killing plants. Pipelines are also fitted with a leak detection system linked back to a central control room. A pipeline breakage is detected by a drop in water flow and this automatically triggers a shutdown of the pumping system.

At the tailings storage facilities, a balance is maintained to allow the material to settle, compact and dry out as the water infiltrates back into the groundwater. Trenches and groundwater bores around these facilities intercept the groundwater movement and keep the water table in check to protect the vegetation.

KCGM links together its inspections, flow monitors and warning systems on its pipes, computer balance models, mineral processing research and prediction of water needs, to manage water and groundwater resources and thus protect the environment. KCGM also monitors the condition of vegetation around tailings storage facilities to verify the operation is not causing an impact.

KCGM is focused on the continual improvement of site-wide water supply and use so that a cost effective and low-risk process water supply can be maintained. KCGM has implemented substantial improvements in water use efficiency including recycling of decant water and the recovery of seepage water from the tailings storage facilities.