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Petra Diamonds Ltd - Williamson Tailings Storage Facility wall breach

10 November 2022



Petra Diamonds Limited
Petra) or the (Company)

Update regarding Tailings Storage Facility (TSF) wall breach at Williamson in Tanzania

Petra announces an update following the TSF wall breach and flooding event at the Williamson mine.

Further to its announcement dated 7 November 2022, Petra confirms that no fatalities or serious injuries occurred as a result of the incident. Three injuries of a minor nature have been reported and appropriate treatment has been provided.

The cause of the breach is not yet confirmed and an investigation is underway comprising technical teams from Williamson Diamonds Limited (WDL) and Petra who are at the site. The services of an independent external specialist have also been retained to assist with WDL’s investigation and who will provide a report to the Petra Board.

Impact on the environment and local community

From an initial assessment, supported by the use of satellite imagery, the main portion of the tailings have been contained by the New Alamasi water dam which sits within the Mine Lease Area to the north east of the TSF. A portion of tailings has flowed around the dam into a tributary to the north of the New Alamasi water dam. Flow below the dam consisted mainly of water and was largely contained by the topography.

WDL is working closely and collaboratively with local, Regional and National authorities to assess the environmental damage and to put in place and implement remediation plans as soon as possible. WDL and Petra appreciate the prompt response and assistance that has been provided by these authorities.

A total of 13 dwellings have been affected and the emergency response teams’ immediate priority has been to provide accommodation and humanitarian aid to those affected. A socio-economic survey has been initiated, supported by an external social impact specialist, to determine additional social impact. Extensive and ongoing engagement with communities will continue to take place, together with the Government, to ensure that key stakeholders are kept appraised of WDL’s response, including planned remediation activities.

Technical and Production

WDL’s technical team with the support of members of Petra’s South African technical team are working together on-site to resume production safely and in accordance with applicable standards and procedures. Detailed planning is underway to bring a new TSF into operation which was already under construction at the time of the incident and which requires construction of a new wall on the boundary of the failed TSF. A preliminary estimate suggests that production will be temporarily suspended for up to three months until the new TSF has been commissioned. In the interim, and to minimise the overall/medium term impact of the lost production, planned maintenance will be brought forward along with accelerated waste stripping.

Further updates will be provided in due course.

Petra currently has a 75% shareholding in Williamson Diamonds Limited, with the Government of Tanzania owning the remaining 25%.

~ Ends ~

For further information, please contact:

Petra Diamonds, London Telephone: +44 20 7494 8203

Patrick Pittaway

Julia Stone

About Petra Diamonds Limited

Petra Diamonds is a leading independent diamond mining group and a supplier of gem quality rough diamonds to the international market. The Group’s portfolio incorporates interests in three underground producing mines in South Africa (Finsch, Cullinan Mine and Koffiefontein) and one open pit mine in Tanzania (Williamson).

Petra's strategy is to focus on value rather than volume production by optimising recoveries from its high-quality asset base in order to maximise their efficiency and profitability. The Group has a significant resource base of ca. 226.6 million carats, which supports the potential for long-life operations.

Petra strives to conduct all operations according to the highest ethical standards and only operates in countries which are members of the Kimberley Process. The Group aims to generate tangible value for each of its stakeholders, thereby contributing to the socio-economic development of its host countries and supporting long-term sustainable operations to the benefit of its employees, partners and communities.

Petra is quoted with a premium listing on the Main Market of the London Stock Exchange under the ticker 'PDL'. The Group’s loan notes due in 2026 are listed on the Irish Stock Exchange and admitted to trading on the Global Exchange Market. For more information, visit