The breach led to flooding that extended into certain areas outside of the mine lease area.
Also operating three underground producing mines in South Africa, Petra Diamonds said no injuries or fatalities had been reported due to the TSF wall breach.
The government and mine emergency response teams have been deployed at the mine site, where a probe into the incident is planned to be carried out.
In a press statement, Petra said: “A CEO-led team is being sent to the site to assist the mine team and to provide any support required. Williamson’s management is working closely with local and regional authorities and Petra will provide further updates as information becomes available.”
Petra owns a 75% stake in the Williamson mine while the remaining stake is held by the Tanzanian Government.
Said to be Tanzania’s only important diamond producer, the Williamson mine is an open pit operation based upon the 146ha Mwadui kimberlite pipe that is claimed to be one of the world’s largest economic kimberlites.
The mine was put on care and maintenance in April 2020 to preserve its liquidity. However, its operations resumed in Q1 2022.