BHP Billiton’s Leinster Nickel Operation (LNO) is located 600 km north-east of Perth in the Eastern Goldfields Region of Western Australia. The LNO deposits (known as Perserverance, Rocky’s Reward, Harmony and 11 Mile Well ) are situated within the Wiluna Greenstone Belt and the orebodies are hosted in Komatite Ultramafic lava flows.

Steeply dipping disseminated and massive textured nickel-sulphide mineralisation associated with metamorphosed ultramafic lava flows and intrusions .

The Perserverance orebody has been mined at surface by open cut and extends underground to a current depth of 1 100 m. The Perserverance underground mine is the only mine currently in operation at Leinster. The main orebody is mined by sub-level caving. Surface operations consist of monitoring the subsidence caused by the underground operation, on the completed open pit and surrounding infrastructure. A programme is currently underway to backfill a portion of the pit with waste material, to slow the rate of subsidence and minimize the effects on nearby ventilation and haulage shafts.

The Rocky’s Reward orebody has been mined by open cut and underground stoping methods. A recent scavenge operation, extracting a portion of the crown pillar was completed in June 2005.

Harmony commenced mining in March 2000. The pit was mined in three stages and included cutbacks due to wall failures.

The 11 Mile Well orebody was mined by open cut methods and was completed in September 2005. Although a small operation (18 month project), localized instability of the walls necessitated a redesign after 6 months.

Concentration plant with a nominal capacity 3 Mtpa of ore.

Installing 2 x OK150 tank cells at elevation to minimise pumping costs. Evaluating existing flotation capacity to suit the SSF flowsheet and selecting new duties for the existing cell banks. Extensive flotation floor pump modifications, extensive launder modifications, new samplers and Multi Stream Analyser to provide real time performance data. Minimal tie over time between the old circuit and the new SSF circuit.