Aluminium Decommissioning Study

Western Australia

Calibre assisted the client to develop decommissioning closure plans to provide the basis for closure cost estimates and associated financial provisions.

Closure planning included closure criteria and land use options, as well as current and future shared economic, environmental, and social value.

Project need

The Client engaged Calibre and contractor A in 2021 to undertake a conceptual level decommissioning assessment of the Alumina refinery, in Western Australia. The results of the assessment informed the client of the overall closure liability assessment for the refinery.

Calibre and contractor A undertook the works as an integrated team to complete a seamless Concept Decommissioning Study for the client. The Decommissioning Study developed a Class 5 cost estimate to ±100% accuracy, provided a preliminary implementation schedule and recommended areas to be studied in further detail.

Project solution

The Calibre/contractor Delivery team has relevant mine closure and decommissioning experience having completed many studies for the client over recent years. This enabled the team to mobilise quickly and implement a proven methodology for delivery of the works. The study methodology included the following:

  • Offsite assessment/background data review.
  • Site visit and Decommissioning Strategy development.
  • Estimate and schedule development.
  • Study Report preparation.


The Calibre/contractor Delivery team delivered a conceptual schedule of works and a cost estimate for the refinery as well as the following project outcomes:

  • Recommendations for recontamination including purge and flushing of pipelines and other services suitable for safe demolition.
  • Recommendations for removal of all fuels and oils from storage vessels, service lines, pumps, and motors etc.
  • Disposal options for all flushed solid and liquid waste, including caustic soda; de-energisation of refinery (stored and electrical energy) suitable for safe demolition.
  • Assisted the client in understanding the total cost of the closure through developing the cost estimate for decommissioning, closure execution project, post closure monitoring and maintenance and relinquishment.

Value add

Calibre has previously delivered several closure estimates. The team applied these lessons learnt when reviewing available company information and identifying gaps in previous closure cost estimates (including decontamination and decommissioning) to provide the client with a total cost of closure.

*Image provided is not a representation of the project information, but a stock Aluminium Refinery project in Australia