Abstract:

The selection process for reclaiming mine waste storage has been refined in recent years with the improvement of knowledge, skills, as well as legislative and corporative frameworks related to mine closure. Reclamation of a mine waste storage facility must, among other things, ensure geotechnical and water quality objectives in the short, medium, and long terms. A good practice is to validate the achievement of these reclamation objectives by linking them to compliance targets defined for the site. However, the reclamation method is often selected without defining the performance criteria of the reclamation method that is implicit to meet the closure objectives and compliance targets that are usually linked to water quality, bio-physical stability, and sustainability via a wide range of disciplines. The development of the reclamation performance criteria is specific to each mine waste storage facility and is controlled by processes such as recharge rates, oxygen fluxes, phreatic levels, temperature, etc. This paper presents a methodology that will be applied at Raglan Mine and that can be applied to other sites to determine specific performance criteria required for the reclamation method, which would then be incorporated in the basis of design for developing the closure plan. The performance criteria would also be used to determine the studies and modelling required to support the design based on their relevance to potential reclamation methods. One or several combinations of specific criteria can lead to a satisfactory reclamation, given the interinfluence of some parameters. This approach implicitly defines the level of effort required to achieve the reclamation objectives.

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Nathalie Chevé