8 November 2022
Another tailings dam failure: the Williamson Mine in Tanzania
Posted by Dave Petley
Another tailings dam failure: the Williamson Mine in Tanzania
I’m sad to report this morning that there has been yet another significant tailings dam failure, this time at the Williamson Mine in Tanzania (the location is -3.525, 33.620). There are brief reports in a number of mining related journals, including African Mining Review and Mining Weekly The reports indicate that the eastern wall of the tailings storage facility has been breached.
This is a Google Earth image of the site, which is a diamond mine owned by Petra Diamonds (75%) and by the Government of Tanzania (25%):-
Google Earth image of the Williamson Mine in Tanzania. Note the tailings storage facility on the centre right of the image. Reports indicate that the eastern wall breached.
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Planet Labs captured an image of the site yesterday (7 November) at 07:45 UTC. The image is partially cloudy, especially over the TSF itself, but a large plume of tailings can be seen:-
Planet Labs image of the site of the tailings dam breach at the Williamson Mine in Tanzania. Image copyright Planet Labs, used with permission, dated 7 November 2022.
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I have place the marker at the approximate position of the beach in the wall of the TSF. The plume of tailings has flowed initially to the southeast and then towards the northeast. It appears that some mine waste has entered the local rivers, but the amount in unclear. The plume is over 6 km long and has a maximum width of about 1.2 km. A very rough estimate has a surface area of the plume at about 4.7 km².
There is a Sentinel 2 image of the site, also captured yesterday:-
Sentinel 2 image of the site of the tailings dam breach at the Williamson Mine in Tanzania. Image accessed via the EO Browser.
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This provides a slightly better image of the breach in the TSF wall. As yet I can find no images of the event on the ground.
This is the second major tailings dam failure in Africa in two months, following the Jagersfontein event on 11 September 2022 in South Africa.
Interestingly, Wikipedia reports that the mine was mothballed in April 2020. The owners offered it for sale in September 2021, indicating that it was permanently closed. However, Investors’ Chronicle reported last month that production had restarted.
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Reference
Planet Team (2022). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
Man’s need for diamonds has always outweighed our interest or capacity to support one another … it’s a century of history and more…and the actors here – are familiar names – so is the working and responsibility scenarios. There will be more ….
Nothin happens to those “responsible”, maybe throw some cash around in the right places … cozy up to some geotech/mining sector folks for a while to make it seem like there is a real interest … then, back to usual.
The Jagersfontein group is seeking permission to restart production …..
I have years remediation knowledge and know well the Mining industries seldom have a knowledge of how to repair and these breaches, much less plans to do so. They most often pull the actual Miners into cleanup mode without any knowledge or training to successfully complete the clean up. Furthermore, Mining Engineers seldom know, “How”, to develope a, “Work Plan” , or the Best methods procedures.
For many years, dry stacked or filtered tailings have been used very successfully around the world, even on steep slopes of the Andes. My brother was involved in many of these types, but also advised Vale years before the Samarco failure to modify to a variation of filtered trails. Some engineering companies still dispute their effectiveness, and this may be the result of that negativity.
Interesting comments and considerations about the status of closure. A mine may close during extracting the ore out the ground during its Life Of Mine operations and thereby producing tailings. Large tailings facilities (from dams or filtered dry stacks) are built to contain mining waste; these include among the largest dams and structures in the world, and must stand in perpetuity. Experience shows that a catastrophic release of mining waste can lead to long-term environmental damage with huge cleanup costs. How long is perpetuity … we must design for closure and post-closure.
I know the place,I grew up in the same region and my brother went to the highschool near the mine.
I’m flabbergasted to know about the failure in this platform instead of the mainstream media in our country.
That site will have raised the TSF with tailings by upstream construction, either by cycloning had built (day wall) for years. Too much water on the TSF, low density tailings and potential for static liquefaction is why this style of construction should be phased out asap.
Time for a change in tailings dam designs. We supplied our infrared heaters for a new tailings mine in Peru, where the engineer, Golders, specified an asphalt dam instead of earth fill. Each individual layer of compacted asphalt was re-heated with our heater to make a sealed bond between layers, leaving an impenetrable and long lasting protection. http://www.asphaltheater.com