15 November 2022

The impact of the Williamson Diamond Mine tailings breach

Posted by Dave Petley

The impact of the Williamson Diamond Mine tailings breach

The high resolution Planet Labs SkySat satellite image of the Williamson Diamond Mine tailings dam breach, which I featured last week, also shows the impact of the mine waste on downstream communities.  This image shows the inundated and overtopped dam downstream of the tailings storage facility (TSF).  At the site of the spillway to the north, now filled with tailings, there is a small community that has been heavily affected by the waste:-

The impact of the mine waste plume from the Williamson Mine tailings dam failure.

The impact of the mine waste plume from the Williamson Mine tailings dam failure. Planet Labs SkySat image, copyright Planet Labs, used with permission. Image captured 9 November 2022 at 11:21 UT.

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Further to the northeast there is another set of properties affected by the tailings:-

The impact of the mine waste plume from the Williamson Mine tailings dam failure.

The impact of the mine waste plume from the Williamson Mine tailings dam failure. Planet Labs SkySat image, copyright Planet Labs, used with permission. Image captured 9 November 2022 at 11:21 UT.

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For these households the impact of the mine waste will have been devastating.  Reuters reports that 13 households have been displaced, whilst mining operations have been suspended for three months pending an investigation into the causes of the disaster.  The incident is being investigated by the National Environment Management Council (NEMC) in Tanzania.  Petra Diamonds itself has a statement on its website dated 10 November 2022, which includes this:

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.

[Williamson Diamonds Limited – WDL] 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.

I will leave it to the reader to judge as to whether they feel that this is an adequate response to an accident of this scale.

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Reference and acknowledgement

Thanks to Rob Simmon at Planet Labs for acquiring and posting the image.

Planet Team (2022). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/