When a gold mine is situated in an Australian desert where temperatures can reach 51 °C nothing is ever easy. In this extreme heat, every process at the mine must be carefully planned to obtain the desired results. This is the case with the Plutonic gold mine some 940 kilometres north-east of Perth.
The mine depends on the power plant for its production needs and the personal comfort and safety of the mine’s staff. Under the very difficult conditions in such a remote region the plant’s reliability is of paramount importance as the mine’s very survival depends on the availability of power.
The 16.5 MW power plant of Barrick Mining Company (Australia) Ltd (formerly Plutonic Resources Ltd.) was built and commissioned in 1997 and features four Wärtsilä 18V34SG gas engines. When the contract was awarded, the Wärtsilä 34SG engine was relatively new on the market and had only been used previously in single-engine cogeneration applications.
For the Plutonic gold mine installation the four generating sets were required to run in parallel with each other, as well as in parallel with the existing diesel power plant when the need arose. There was also a requirement to start up the processing mills where a high level of load acceptance was a prerequisite.
During the tendering process, the planners and consultants at Plutonic recognized the many advantages of having an installation built around several reciprocating engines compared to having a combined cycle gas turbine power plant at the mine. A combined cycle plant was Wärtsilä’s competition at the time but this appeared to be too inflexible for a remote mine site application. The benefit of a four-generator reciprocating plant with quick start capability allowed for greater flexibility.
Additionally, the maintenance of the individual reciprocating gas engines does not affect the running units whereas a combined cycle plant would reduce the output of the steam turbine should one of the proposed three gas turbines be out of service. The four Wärtsilä gas generating sets are configured to run in parallel with the original diesel plant, which is now used as a peaking and back-up plant.