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Brazil prosecutor calls for emergency safety measures at tailings dam at former Poços de Caldas uranium mine

Federal Public Prosecutor’s Office calls for emergency measures to prevent failure of tailings dam at former Poços de Caldas uranium mine

Decommissioning Projects – South/Central America  8 Feb 2019

The Federal Public Prosecutor’s Office (MPF)  has recommended to the President of the Indústrias Nucleares do Brasil (INB)  and to the President of the National Nuclear Energy Commission (CNEN)  that, by March 30, all necessary steps be taken to fully implement the Emergency Action Plan for Dams (Paemb) on the tailings dam of the Mineral Treatment Unit (UTM), located in the municipality of Caldas, south of the state.
This dam contains radioactive material resulting from the first uranium mine operated in Brazil.
The exploration lasted from 1982 to 1995, when it was closed, on the grounds that the activities were economically unfeasible. Even after the end of the mine, the mine pit containing mud with radioactive waste, a decontaminated ore processing plant, dozens of equipment, and the dam with thousands of tons of uranium, thorium and radium waste remains in the mine.

In September of last year, INB noted that an “unusual event” occurred at the UTM-Caldas dam, which was immediately communicated to CNEN and the Brazilian Institute of the Environment (IBAMA) . Such an event consisted of turbidity and reduction of water flow at the outlet of the overflow pipe system of the structure. Also, actions were immediately initiated to investigate the causes of the event, by collecting special samples and intensifying the field inspections and reading the dam instrumentation.
A technical report produced by an emergency contractor at the Federal University of Ouro Preto (UFOP)  concluded that the overflow pipe system of the tailings dam is seriously compromised and that the infiltrations found on its walls favor the occurrence of so-called piping.
Piping is a process of internal erosion that damages the structure of the dam, increasing the probability of rupture, which requires immediate measures of correction and intervention [view here].

About two weeks ago, representatives of the Brazilian Nuclear Industries presented to the MPF the measures that are being implemented as a matter of urgency to change the mechanism of the overflow pipe dam system, preceded by a provisional auxiliary system, as well as the Paemb and the schedule of its Implementation. Regarding the Paemb, no concrete action has been taken so far.
For the Federal Public Prosecutor’s Office, the relevance and complexity of the facts, already worrying about the possibility of rupture of the structure, are more serious when the tailings are considered to consist of radioactive material.
The closure of uranium exploration activities occurred in 1995, without concrete measures being taken to decommission UTM-Caldas and environmental recovery for the damages caused. The omission of INB led the Federal Public Prosecutor to file a Public Civil Action No. 4106-80.2015.4.01.3826 , in the year 2015, to demand the full environmental recovery in the area of the project. “The longer this situation lasts, the lack of concrete measures for decommissioning and environmental recovery, the greater the exposure of the environment (fauna and flora) and the population to the risk of serious and harmful events,” warns MPF.

Transparency – Another point addressed in the recommendation concerns the need and the right of the populations neighboring the project, which can be affected in the event of a possible rupture, to receive information about the dam situation in clear and accessible language.
Therefore, the MPF recommended that in five days, INB and CNEN should be widely disseminated to civil society, especially to communities that may be directly affected by a possible incident, about the risks they are exposed to.
The information should cover both the “unusual event” occurred on Sep. 25, 2018, indicating the characteristics and causes of the occurrence, as well as the potential risks arising from the situation in which the dam structure is located, the measures taken by the entrepreneur to stabilization of the enterprise and the content of the Emergency Action Plan (SAP). (MPF Feb. 7, 2019)

The latest Federal Public Prosecutor’s Office action in this case apparently was triggered by the Brumadinho tailings dam disaster on Jan. 25, 2019 (see details). http://wise-uranium.org/udsam.html#POCOSDEC http://wise-uranium.org/udsam.html#POCOSDEC

February 9, 2019 - Posted by Christina Macpherson | Brazil, safety