A technical team from Tanzanian diamond mining company Williamson Diamonds (WDL) is working with a South African technical team from its parent company, London-listed Petra Diamonds, to safely resume production at the Williamson mine, where a tailings storage facility (TSF) breach occurred earlier this week.
Petra, which owns 75% of the Williamson mine, reported on November 7 that an eastern wall of a TSF at the mine was breached, resulting in flooding away from the pit and extending into areas outside of the mine lease area.
In a November 10 update to shareholders, Petra confirmed that there were no serious injuries or fatalities as a result of the breach.
"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 under way. The services of an independent external specialist have also been retained to assist with WDL’s investigation," Petra noted.
Further, the diamond miner said that an initial assessment, supported by the use of satellite imagery, has determined that the main portion of the tailings have been contained by the New Alamasi water dam, which sits within the mine lease area to the northeast 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," Petra said.
It pointed out that 13 dwellings had been affected by the TSF breach and that emergency response teams have made available accommodation and humanitarian aid to affected households.
"A socioeconomic 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 key stakeholders are kept appraised of WDL’s response, including planned remediation activities," Petra added.
Meanwhile, detailed planning to bring a new TSF into operation is under way. The new TSF was already under construction at the time of the November 7 breach.
Petra said preliminary estimates suggest that production at Williamson may be suspended for up to three months until the new TSF has been commissioned.
During this period, planned maintenance will be brought forward along with accelerated waste stripping in order to minimise the overall impact of lost production.