Environment

Tailings are one of the most significant waste streams generated by the mining industry. They are created as mined ore is crushed, milled and processed to separate the valuable minerals from the ore. Tailings typically consist of a slurry of fine mineral particles and water, which are either incorporated into materials used to backfill mined-out underground stopes or pumped in a slurry form into a specially designed and engineered facility, known as a tailings dam or a tailings storage facility (TSF).

Our TSFs

Blanket has two operational TSFs; these include the old TSF, which is nearing the end of its life, and a new TSF which was constructed and commissioned during 2023.

The old TSF was constructed in 1995, and deposition on the dam was phased out towards the end of 2023. The dam continues to be monitored with regard to phreatic levels and stability and will be closed and rehabilitated in a responsible manner. The new Blanket TSF was designed by Knight Piésold and is being constructed taking the principles of the Global Industry Standard for Tailings Management (GISTM) into account. A site selection process was undertaken, and the preferred site has a Zone of Influence with few residents and less potential impact on rivers and Blanket Dam than other sites under consideration. Residential developments are all upstream of the TSF, and the area is not prone to landslides, flooding or seismic activity.

The TSF has been classified as Type 3 waste, and a barrier system of a 1.5mm HDPE geomembrane placed over a 300mm compacted clay liner has been put in place. According to the SANS 10286 Safety Classification, the facility is classified as a medium hazard.

The new TSF has an expected life of 20 years, with a footprint area of 65Ha, and the planned solids to be deposited is 14.4 million tonnes. Construction is being undertaken in Phases, with Phase 1A and the first slurry line completed and commissioned in October 2023. Phase 1B and the second slurry line will be completed in 2024, with Phase 2 and final commissioning in 2025. The TSFs are operated by a third-party contractor, Fraser Alexander Tailings (Pty) Ltd, and the Engineer of Record is Epoch Resources (Pty) Ltd.

Dam Safety

TSFs need to be carefully monitored and maintained to ensure the stability of the dam walls and to prevent seepage of contaminants into the local environment. We take tailings management very seriously and are working to ensure our practices align with the requirements and recommendations of GISTM. Our approach to tailings management is set out in our Tailings Management Standard and includes:

• Monitoring technology – such as piezometers to monitor stability; these are checked monthly by conducting upset tests as well as the installation of sensors on the TSFs for remote monitoring.
• Routine Inspection – daily walk around inspections are undertaken to check for cracks.
• Engineer of Record – We have an Engineer of Record (EoR) who is responsible for assessing the characterization of the TSF, capacity of the facility as well as slope stability. An inspection by the EoR was conducted in March 2023. There were no incidents.
• Regular Surveys – Surveys are carried out once per year.