Element 5 – Closure Activities

Closure activities are the physical works carried out to close the site. These may be achieved during operations (progressive closure) or in the closure period (final closure). Closure activities are undertaken to achieve specific closure objectives.

Not all closure activities will be subject to the same level of evaluation. Some will be relatively standard; in other cases there may be many alternatives with significant differences in terms of cost, social acceptance, effectiveness, risk profile and other factors. In these cases, final selection of closure activities may take years of effort, involving input from stakeholders, research programmes, design studies and specific risk evaluations.

The general approach is as follows:

• A preliminary ‘long list’ identifying potential closure activities is generated. This list is typically developed based on several inputs, including professional experience, literature reviews and stakeholder input
• An initial screening to eliminate options that are not feasible, either on their own or in combination with other measures
• The options that have been eliminated in the screening should be documented, along with the rationale for their elimination. This documentation helps ensure that decisions are traceable and facilitates coming back to ‘long list’ options if conditions change
• To further narrow the list, screen-level engineering designs or technical evaluations to help quantify evaluation parameters such as cost. Designs may be advanced to a conceptual or pre-feasibility level to further screen out alternatives
• Where multiple options remain at this stage, use a multiple accounts analysis to compare and rank options such as cost, environmental impacts, social acceptance, technical risk etc
• If a multiple accounts analysis is used, the options assessed should be ranked
• At the completion of a multiple accounts analysis, sensitivity checks should be carried out to evaluate the extent to which rankings are affected by credible ranges for either the inputs or the weightings placed on different parameters
• Formal risk evaluations may also be carried out on closure alternatives to demonstrate their effectiveness at risk reduction in various domains