On Monday 7 November 2022, a significant 150m wide breach impacted the eastern wall of the tailings storage facility at the Williamson diamond mine in Tanzania.
Extensive flooding was recorded flowing away from the open pit and into certain areas outside of the main lease area, with a portion of tailings known to have flowed around the dam into a tributary to the north of the New Alamasiwater dam.
The resulting tailings plume grew to more than 6km long with a maximum width of about 1.2 km, and an estimated a surface area of 4.7 km².