Rehabilitation metrics and value of knowing what can be achieved

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A4   |   Letter


SRK News | Issue 58
Mine Closure: Can closure create opportunities?

Matthew Law, Senior Environmental Management Consultant and Economist      

 

Along with other countries, holders of mining and prospecting rights in South Africa must provide financial guarantees for rehabilitation. Rehabilitation is achieved when closure commitments are met, confirmed by a Closure Certificate issued by the Department of Mineral Resources.

Although South Africa’s legislation compares favourably to other countries, there are few examples of successful mine closure. More than 6,000 mines have been abandoned without adequate rehabilitation. Too often, both mine owners and regulators overlook the importance of realistic closure targets, with owners making impracticable commitments, which cannot be implemented or are ignored. 

In the past, failure to comply posed a limited risk. However, mine closure will soon be regulated under the National Environmental Management Act (NEMA). It will require plans for ongoing rehabilitation, closure and managing environmental impacts. Financial provision will need to be independently audited and subjected to stakeholder engagement. New regulations will impose strict penalties, including possible imprisonment, and stakeholders are becoming increasingly vocal about inadequate closure. It is therefore essential for mining operations to understand what level of rehabilitation can be achieved and the residual environmental impacts anticipated, what measures are needed annually and at closure and what they cost, and what metrics are needed to assess rehabilitation to facilitate reporting and management.

SRK recently agreed to ascertain rehabilitation performance at a large open-cast mine on South Africa’s west coast, and what rehabilitation can be achieved using current methods. The owners also required a robust system to monitor and measure progress without specialist supervision. Previous owners of the mine had committed to return the site to baseline grazing potential, which owners and regulator believed was achievable, despite intensive rehabilitation that failed to deliver.

SRK sub-contracted a restoration ecologist to sample proximate sites as a pre-mining baseline. A customised grazing index was developed, and the grazing value of these sites was calculated using the index. The results provided the first quantitative measure of baseline grazing value, a metric to assess rehabilitation performance – a significant step in closure planning. Subsequently, the grazing value of areas under rehabilitation was calculated using this index. The assessment revealed that although significant vegetation cover had been achieved, progress in returning the site to agricultural potential was slow, indicating that at the historical trajectory of rehabilitation, residual liabilities would be high, and that additional or alternative interventions were required during the remaining life of the mine. The use of the grazing metric will help the owner plan enhanced rehabilitation techniques, accurately assess and report on rehabilitation, consider adaptive management of rehabilitated areas, and update plans to accurately reflect costs. This will significantly reduce the owner’s risks at closure, in the face of more stringent closure regulations and penalties, and increased oversight in the sector.

Matthew Law: mlaw@srk.co.za

 

SRK Worldwide