Uranium tailing facilities dams

The mining industry was impacted by two major industrial disasters related to tailing facilities dams in less than four years. The control of these facilities - in working mines as well as in remediated mines - is a permanent concern. Orano Mining as a member of the ICMM, (International Council on Mining and Metals), committed to publish the list of its largest tailing storage facilities, their dimensions, characteristics, and ways of monitoring in this report.

In France

There are 9 dams of 15 to 65 m in height and 110 to 1,700 m in length but only one with the presence of a cover water (Bois Noirs Limouzat site). The dams are constructed using sand from the cycloning of tailings, or mining waste rocks.


In Niger, the dams, made of waste rocks, are lower in height. In Gabon, the remediated site is the only dam with a cover water.

A special monitoring implemented by Orano Mining

In France

Only the Bois Noirs dam (H max : 42 m, L: 508 m) is considered a type A dam subject to internal monitoring and regulatory monitoring.

The other dams in France are subject to internal monitoring by Orano and are inspected by an external expert every five years.

The results of monitoring of structures show that they are in a satisfactory state regarding their stability

In addition, within the framework of the French National Plan for the Management of Waste and Radioactive Materials (PNGMDR), a working group is defining the criteria to be taken into account in order to conduct a study of their very long-term stability (3,000 years and sensitivity study up to 30, 000 years).


All of these dams meet regulatory requirements and are subject to internal monitoring by Orano, with certain structures undergoing inspection by an external expert.

A noticeable effort has been conducted in recent years on sites to improve their monitoring in operational and organizational terms. The general state of dams is satisfactory.

  • Detailed table of uranium tailing facilities dams

For more information on the International Council on Mining and Metals work in progress

Orano Mining, with all the company members if the ICMM, is currently working on the definition an appropriate tailings storage facility governance framework. This should minimise the risk of catastrophic failures.

Links to the ICMM website

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