The GISTM has a strong focus on closure. One of the objectives of the GISTM with regards to sustainability is that TSFs must be capable of being closed with limited management and maintenance and physically and chemically stable for the long term. This leads to the requirement that a TSF should be planned, designed, constructed, operated and closed on the assumption that it will be a permanent landform that cannot develop credible catastrophic failure scenarios.
The closure of a TSF should be considered at the conceptual phase of the design to ensure that there are no impediments to safely closing the facility at any point of its life, including at the end life of the mine. This requires the development of a preliminary closure plan that will be used to inform the design, with the preliminary plan including at least closure performance objectives and being used to inform a multi-criteria alternatives analysis.
Closure principles are also applicable to operational facilities that are not in a safe state for closure and require that a closure plan be developed for existing facilities. The plan can be iterative and develop as the end of facility life approaches. The GISTM acknowledges that TSFs are subject to change as they develop. Principle 2 requires that an integrated knowledge base be developed to inform safe management throughout the life cycle. Changes to the closure plan for new and existing TSFs through the operating period must be included in the Operation, Maintenance and Surveillance manual so that activities during operations support the closure plan and objectives.
Closure planning for a GISTM-compliant facility is an iterative process starting at concept phase and continually improving as more knowledge is generated through the TSF life.
