Early Lessons from Ranger Uranium Closure Cost Overruns

Key Points

  • ERA’s announcement on Friday 8 October 2021 that it faces ‘material’ cost and schedule overruns associated with rehabilitating and closing the Ranger uranium mine, highlights how difficult it is to understand the closure risks that need to be addressed on a mine site, and how important it is to undertake studies designed to improve understanding of these risks, how to address them, how much this will cost and how long the costs will be incurred. 
  • Tailings and geochemistry are two of the highest risks associated with both the operation and closure of mine sites.
  • In-pit tailings disposal needs to consider the cost of remediating residual risks.
  • Closure cost estimates need to be developed using a robust method and costs need to continue to be refined over the life of an operation by conducting trials and progressive rehabilitation to test the assumptions that estimates are based on.
  • Depending on the level of uncertainty associated with closure costs, contingencies may need to be included until levels of knowledge improve.