Tranforming Mining Operations for a Sustainable Future

By Themba Nkosi, Sibanye-Stillwater Chief Sustainability Officer - Corporate Affairs

In the face of escalating environmental challenges including water scarcity, the mining industry is grappling with the urgent need for innovative water management solutions. One of the most pressing issues is Acid Mine Drainage (AMD), which could pose significant threats to freshwater ecosystems and drinking water supplies.

Sibanye-Stillwater, a multinational mining and metals processing group, has taken the initiative to address this critical concern at its South African gold and PGM operations, by viewing mine-impacted water as an opportunity for value recovery and a sustainable solution to water scarcity. Sibanye-Stillwater initiatives, which include potable water production and high-value fertiliser extraction, highlight its commitment to a greener and more water-conscious future.

The acid mine drainage challenge

AMD has long been recognised as a potential significant environmental problem worldwide. When water interacts with sulphide minerals in mining operations, it forms sulfuric acid, which leaches metals from old mine workings, potentially contaminating nearby water bodies if not managed.

Unrestricted flow of acidic water into streams, rivers, and groundwater, can cause severe harm to aquatic ecosystems and human health. In 2006, the United Nations identified AMD as the second most pressing environmental concern after global warming.

In recent years, growing environmental awareness has led to improved mining practices and regulations aimed at mitigating AMD's impact. Sibanye-Stillwater, in line with its commitment to sustainable operations, has pioneered a range of unique water treatment projects in its Southern Africa operations, that contribute to its water independence strategy, whilst also delivering substantial environmental benefits, including management of AMD.

Unlocking value from mine-impacted water

Sibanye-Stillwater has identified an opportunity to transform mine impacted water from its SA gold operations into a valuable resource. By implementing innovative water treatment techniques, the Company has been able to extract value from the water bodies potentially finding a solution to the mining industry’s challenges.

Some of the Company’s programmes include:

• Water Reuse - Effluent treatment processes remove contaminants and pathogens, making the water suitable for potable purposes. This approach conserves precious resources

• Nutrient Recovery - Nutrients like nitrogen and phosphorus can be extracted from the effluent and used as fertilisers, reducing the reliance on synthetic fertilisers.

• Resource Extraction - Effluents may contain valuable metals or compounds that can be recovered for reuse or sale, providing economic benefits while reducing waste.

Sibanye-Stillwater's potable water production

Sibanye-Stillwater recognises the need to optimise water usage within its mining operations, as water is an essential resource across the mining value chain. Considering the strain on national potable water resources in South Africa and the projected water deficit in South Africa by 2030, the Company has taken decisive steps to ensure water security for its operations. This approach also supports water and sanitation services for its neighbouring communities.

Through advanced technologies, such as reverse osmosis, nanofiltration, ultrafiltration, media-filtration, selective precipitation, and ion exchange Sibanye-Stillwater has demonstrated competence in converting mine-impacted water into safe and potable drinking water. This addresses water availability for mining operations, reduces the demand for freshwater, conserves resources, and contributes to overall sustainability.

Currently, Sibanye-Stillwater operates four potable water production plants at its SA gold mining operations: Kloof, Driefontein, Ezulwini, and Burnstone. With a combined production capacity of 37 million litres of SANS 241: 2015-compliant drinking water per day, these plants exemplify the Company's commitment to water stewardship.

Strategic partnership and future potential

Sibanye-Stillwater is also advancing its commitment to enabling sustainable post-mining economies and systems in its operating areas.

The water element of this project focuses on sustainable solutions in agriculture, water, and energy, specifically for post-mining scenarios. During its pilot phase, this element has shown promising results. Sibanye-Stillwater has entered into a strategic partnership with Trailblazer Technologies as part of its IXs innovation programme. This partnership allows for the testing and development of water treatment technologies. These technologies not only treat mine water but also have the potential to produce large volumes of high-value fertilisers as by-products. The results from the pilot studies indicate much promise from Sibanye-Stillwater's innovative approach to water treatment.

The processes being tested transform highly saline water into nearly salt-free, demineralised water through two primary absorption and elution stages. The waste generated from the processes can be easily refined to produce valuable by-products, including components of fertilisers for agricultural use and other valuable salts.

The Company has identified two critical high-value fertiliser products: Potassium Nitrate and Ammonium Sulphate. These fertiliser products are water-soluble and rich in the essential nutrients that many crops require. Upon application, they promote plant growth, improve fruit quality, and enhance resistance to diseases and stress conditions, while also improving soil quality for future crops. By producing these fertilisers from mined water, Sibanye-Stillwater aims to localise a sustainable source of high-value fertilisers thereby reducing South Africa's dependence on imports.

Sibanye-Stillwater's water treatment innovations showcase a commitment to sustainable mining practices and responsible environmental stewardship. By reimagining mine-impacted water as a valuable resource, the Company reduces its environmental footprint and contributes to water security and fertiliser production in South Africa.

In areas where mine closure is planned, advancing these opportunities creates secondary economic stimulation in the agriculture and manufacturing sectors, driving local economic development and employment creation, whilst augmenting land and environmental management. Sibanye-Stillwater maintains its commitment towards a more sustainable and efficient mining industry by entrenching water reuse, waste minimisation and recycling.

Looking ahead, Sibanye-Stillwater aims to expand these sustainable practices to its other global operations and continue to innovate in water treatment and waste management. As the Company moves forward, it aims to set new standards for the entire mining industry and establish itself as a leader in sustainable mining. By entrenching water reuse, waste minimisation, and recycling, Sibanye-Stillwater remains committed to a more sustainable and efficient mining future.