Tommi Kauppila, Geological Survey of Finland, P.O.Box 1237, 70211 Kuopio, Finland; tommi.kauppila(at)gtk.fi
Mine closure is a long process that starts at the early feasibility phase at latest, continues throughout the production phase of the mine, and ends with post closure monitoring of the success of the closure actions and the stability of the site. A simplified outline of the closure process is shown below (Figure 1). The lengths of the arrows are not proportional to the actual time periods of the various phases and many of the phases overlap. The image also does not include any permitting processes that, depending on the jurisdiction, may considerably increase the complexity of the mine closure process. However, the image gives an overall view of the steps in a mine closure process.
Figure 1. A generalized outline of the mine closure process. This outline does not include the regulatory processes and documents.
- Interact with feasibility and planning: The early phases of the mine closure process require data from the feasibility studies and mine planning. The flow of data also flows in the opposite direction because mine closure and its costs have to be incorporated in all plans and feasibility assessments. The EIA process is also commonly underway at this point.
- Consult stakeholders: External stakeholders’ views, concerns, and expertise are key to defining the post closure land uses and setting closure objectives. These consultations can be incorporated into other early phase stakeholder consultations regarding the project.
- Define closure objectives: Mine closure planning must be based on a balanced view of the objectives of closure. These are based on the general principle of minimizing risks and maximizing benefits while providing for widely agreed post closure land uses of the site.
- Make a Closure Management Plan (CMP): The Closure Management Plan is an evolving key document to structure the closure efforts during the life span of the mine.
- Keep the CMP up to date: The CMP is continuously updated during the operations to reduce uncertainties and (financial) liabilities.
- Operate for closure: Mines should be ‘operated for closure’ so as not to compromise closure objectives with decisions taken early in the operations.
- Employ continuous closure: Certain facilities of the mine are closed already during the production period when funds, personnel, and equipment are available. Early closure may release some of the financial sureties and it also helps reduce environmental impacts, e.g. by preventing tailings oxidation. Data collection and long term field tests of closure structures and options also are part of continuous closure that feed into the CMP updates.
- Make the final CMP: When the decision to close the mine has been made, it is time to make the final CMP with detailed engineering designs. Here, extensive consultation with stakeholders is again required.
- Close the mine: This is the main decommissioning and closure implementation period.
- Monitor success: Post closure monitoring is employed to verify that closure actions were successful and the objectives have been met.