Tailings Dam Failure

On Monday, November 7th, a Tailings Storage Facility (TSF) owned by Petra Diamonds (75%) and the Government of Tanzania (25%) failed, halting production at the Williamson Diamond Mine [1]. This tailings dam failure triggered nearby flooding in local communities, while no injuries have been reported, the environmental damage is significant. In 2022 there have been 5 tailings dam breaches worldwide, with the Williamson Diamond Mine being the second major failure in South Africa over 2 months. The Jagersfontein TSF disaster in South Africa was among the worst in the region, killing and injuring more than 40 people [2].

Based on global data, 43-50% of all existing tailings dams are at high risk of a TSF failure, with 85% of failures occurring from active TSFs [3]. Recent breaches and failures serve as a timely reminder of the need to effectively manage Tailings Storage Facilities (TSF).

Williamson Diamond Mine Tanzania

The image below visually depicts where the TSF breach occurred and the flow of the waste into the environment. It’s been reported that the eastern wall of the Williamson Tailings Dam was breached resulting in the flooding of toxic mud and mining waste [4]. The plume of the tailings is estimated to cover a surface area of 4.7km2 with waste entering local rivers and the environment [1].

Majority shareholder Petra Diamonds, released a statement advising that a CEO-led team had been sent to assist and provide any support required on the ground [4]. “Williamson’s management is working closely with local and regional authorities and Petra will provide further updates as information becomes available” [4]. Production has been suspended on-site at the Williamson Diamond Mine, pending a full investigation into the incident.

Petra Diamonds has four mine assets located in both South Africa and Tanzania consisting of both underground and open pit operations. This independent diamond mining group supplies quality gems to the international market, focusing on value and quality as opposed to volume. Striving to conduct operations to the highest ethical standards, operating in countries that are members of the Kimberley Process, which is internationally certified to regulate the trade of rough diamonds [5].

Tailings Dam Failures

It’s estimated that there are between 29,000-35,000 existing tailings storage facilities around the world, containing approximately 223 billion tonnes of wastewater [3]. There is an increased risk and trajectory for future failures due to existing TSFs receiving more wastewater than originally scoped for with the reprocessing of tailings escalating the volume of wet load and stress.

Without TSF best practice principles, including the life of facility management and rigorous independent stability analysis, TSFs are at risk of collapse. It’s estimated that between 50-65% of TSFs were built circa 1990 with outdated frameworks and guidance [3]. The risk of future tailings dam failures is increasing both in frequency and severity.

As the clean-up of the Williamson TSF failure begins and the Southern Hemisphere of the world moves into an unprecedented third period of La Niña. Increased rainfall has the potential to compound already challenging conditions, with mining companies around the world now bearing the burden of managing Tailing Storage Facilities in both operational, abandoned and legacy closed sites.

Minetek offers an alternative to raising Tailings Storage Facility or building a new dam. Our enhanced evaporation system can be utilised to draw down water levels, and defer the need to lift the TSF for a number of years. Leave your details below to learn more.