During FY 2017 Petra introduced the successful monitoring of on-site rehabilitation by making use of Land Function Analysis (“LFA”). The LFA method is internationally recognised as a field-based monitoring procedure, based on recent, crossdisciplinary research, and can be applied to a very wide range of landscape and climate types and a variety of land uses.
It uses visually assessed indicators of soil surface processes that gauge how effectively a landscape is operating as a biophysical system, monitoring surface hydrology, rainfall, infiltration, run-off, erosion, plant growth and nutrient cycling.
All information is gathered in the field to populate a database, providing intelligence regarding the stability, nutrient cycle and infiltration rate of the specific site. Results can then be compared with other benchmark sites (‘undisturbed’ areas in approximately the same location and climatic conditions).
In April 2017, LFA surveys were conducted on all of Petra’s South African mine sites. The analysis indicated that some of the rehabilitated areas in the town of Kimberley are, biophysically, very healthy, and are even performing better than a corresponding site in the region of Gauteng, which experiences high rainfall. These sites in Kimberley are also out-performing the benchmark site within Kimberley itself, which is perceived to be pristine. Subsequently, said sites can now be classified as ‘rehabilitated’, meaning that the financial provisions made by the mine for their immediate rehabilitation can be removed, saving costs in financial guarantees. Furthermore, it removes the need for further action at these sites, such as costly sloping, treatment of substrate or revegetation.
Petra expects to carry out an initial LFA survey at its Williamson mine in Tanzania in FY 2018.