(Alliance News) - Petra Diamonds Ltd on Wednesday said there is a low risk of further breaches at the tailings storage facility wall breach at the Williamson mine in Tanzania.
Earlier this month, the London-based diamond miner focused on South Africa and Tanzania said the eastern wall of the storage facility was breached due to flooding.
Petra said Williamson Diamonds Ltd, the owner and operator of the Williamson mine, has now constructed an initial six metre high wall to close the breached area.
Williamson Diamonds constructed containment walls upstream and downstream of the New Alamasi water dam, while buttressing of the New Alamasi water dam wall is underway.
Diversion trenches are also being constructed to prevent any build-up of water and to enable rainwater to flow into the surrounding rivers and streams, Petra said.
It added that a preliminary assessment found the failure was subsidence of a portion of the East wall of the facility by around 1.5 metres. This enabled the water to crest the wall and initiate the breach.
The root cause of the subsidence has not been determined and will require a forensic geotechnical investigation to be completed. The design of a new storage facility is currently under review and is expected to be finalised in February.
It is now expected that this new facility will take longer than initially anticipated to become operable, but interim deposition options are being developed that may enable the Williamson mine to resume production in the middle of 2023, Petra said.
No fatalities or serious injuries occurred from the incident, Petra confirmed, and a temporary rehousing scheme is being planned for the affected families.
Petra currently has a 75% shareholding in Williamson Diamonds, with the government of Tanzania owning the remaining 25%.
Shares in Petra Diamonds were down 4.2% to 91.00 pence on Wednesday morning in London.
By Jaskeet Briah; jaskeetbriah@alliancenews.com
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Petra Diamonds (PDL)