West Rand Tailings  Retreatment Project

2014 CASE STUDY:

“Fifth mine” in the pipeline

Sibanye’s West Rand Tailings Retreatment Project (WRTRP) is not simply a project to recover valuable minerals from the many tailings storage facilities (TSFs) deposited over decades on the West Rand. It also has potential to address some of the region’s more pressing environmental challenges.

Moreover, in line with the profitability needed to ensure sustainability, the WRTRP has been designed to be cash flow-positive over its entire life, particularly during the early construction phases. The project awaits permitting from the authorities and a definitive feasibility study (DFS) is due for completion during the first quarter of 2015.

The consolidation of the West Rand surface resources of the Cooke Operation with Sibanye’s acquisition of Gold One International Limited’s 76% holding in the Cooke Operation in 2014 under Sibanye has been a crucial step in improving the project economics, enhancing project flexibility and ensuring the project’s future success.

The WRTRP comprises Sibanye’s tailings resources from the Driefontein, Kloof, Libanon and Venterspost properties, as well as the tailings resources of the four mines, which make up the Cooke Operation as well as older ones from the veteran Randfontein mine to their north.

The WRTRP now has access to over 700Mt of tailings containing 6.5Moz of gold and 98Mlb of uranium – all within a radius of 35km from the Libanon mine. The WRTRP resource is equivalent to some two-thirds of the West Rand’s overall tailings resource, reckoned to be in the region of 1.3 billion tons, containing approximately 11Moz of gold and approximately 170Mlb of uranium.

Assembling the tailings resources under the Sibanye corporate umbrella was essential simply because ownership of a larger number of TSFs with their individual grades and metallurgical characteristics permits greater flexibility in their scheduling for treatment, and justifies the construction of a high-volume gold and uranium processing plant.

During the initial phases, the Kloof 1 and Driefontein 2/3 plants may be used to process old, higher-grade gold-bearing rock dump material on a comparatively small scale once the surface rock dump (SRD) resources they are currently processing have been depleted.

A pre-feasibility study (PFS) on the WRTRP, completed in 2014, yielded a positive outcome, which justified further feasibility studies being done. A decision was, therefore, taken to further advance the concepts developed during the PFS in a DFS, which focused on leveraging existing surface infrastructure, including the existing surface gold plants as well as the available uranium treatment capacity at Cooke 4 to reduce upfront capex while generating early cash flow and optimising the utilisation of the existing surface processing facilities. The development of a new high-volume, central processing plant can then be developed in phases, allowing for the staging of capital. The permitting process is ongoing and will extend into a front end engineering design (FEED) phase should the DFS prove feasible and once a decision has been taken to progress the study. Analysis of the extent, complexity and operating requirements of a pilot plant, expected to be implemented during the FEED phase, has also begun. The pilot plant will not only allow for optimisation of the actual plant operating conditions but also enable training of personnel once the new metallurgical facility is operating. A further benefit of the pilot plant will be the ability to test different feed sources from the various tailings located on the West Rand prior to bringing them online.

The following benefits are envisaged:

The WRTRP, if fully developed, will eventually process 4Mt of sand and slimes per month to deliver a peak annual gold output of approximately 260,000oz and approximately 3.5Mlb of uranium over an operational life of some 20 to 25 years. Approval by the Board awaits positive outcomes from the DFS and permitting process.