Dam Safety in Brazil: New Standards Published
The resolution requires the operator to register all dams at any stage of construction or operation as being under their responsibility, even if the dam is not operating. In cases in which the registration is cancelled or there is a dam decommissioning, the operator must prove that the dam has closed by presenting to CNEN documents prepared by a legally qualified professional.
For dams that have more than one dam structure, the criteria considered for the highest-scoring dam in risk classification should be extended to the other structures so that there is no possibility of registering any assist dam as an independent structure. In such cases, the studies and plans to be carried out for the main dam must also include the specifications for each associated auxiliary structure. For new mining dams that contain radioactive tailings, registration must be submitted by official letter prior to the start of construction. For existing dams, registration must be done within 10 business days of the effective date of this resolution (its time of publication).
In addition, the dam operator must prepare a flood map for each dam within 60 days from the effective date of the resolution. In situations in which a dam is located downstream of the structure being mapped and within the influence area that could flood, the analysis should consider—and the flood map should include the multiple structures.
Furthermore, the dam operator must implement a full-time safety monitoring system, with video surveillance of its structure 24 hours a day, within six months after the date of publication of the resolution. The information from the monitoring system must be available to the Civil Defense and CNEN and kept in the system for a minimum of 90 days.
Regarding the DSP, the resolution stipulates that it should be prepared by the beginning of the first dam filling, at which time it must be made available for use by the Dam Safety Team and for consultation by inspection agencies and the Civil Defense.
The DSPR must indicate the actions that will be taken by the operator to maintain dam safety, which must be performed up to a maximum period of at least every three years.
The EDAP must be prepared for all mining tailings dams containing radioactive tailings, and a physical copy of the EDAP must be made available to the state’s city hall, Civil Defense and CNEN. The EDAP must be updated by the operator whenever there is a change in the means and resources available to be used during an emergency and at each Periodic Dam Safety Review.
Every six months, the operator must perform an RSI, documented in a Regular Dam Safety Inspection Report, which the operator must send to CNEN between March 1 and 31 and again between September 1 and 30.
An SSI must be performed whenever anomalies with a score greater than 10 are detected in the Risk Category of the Classification Matrix or in any situation that might impair the dam's structure.
ANA Resolution No. 123/2019
ANA Resolution No. 123/2019 delegated to the Superintendent of Regulation the authority to examine, determine and classify the dams that are under the responsibility of ANA. The classification will be by risk category, associated potential damage and volume, according to the PNSB. The resolution also gives the Superintendent of Regulation the authority to make public the specific acts related to the classification and reclassification of dams.
According to the PNSB, the classification by risk category should be made according to the dam’s technical characteristics, the physical condition of the enterprise and its compliance with the Dam Safety Plan. The classification by category of potential associated damage must be made according to the potential loss of human life and the potential socioeconomic and environmental impacts resulting from the dam's rupture.
The resolution also determined that, in the event of a rejection of or a partial granting of a classification revision request, the operator may, within 30 business days from the decision, submit a request for reconsideration to the Superintendent of Regulation. If the request for reconsideration is not accepted, the operator may, within 30 business days from the rejection, appeal to the Collegiate Directorate of ANA.
The new standards reinforce the wide range of normative acts by Brazil’s public authorities aiming to increase the regulation of dam activities, especially with continuous surveillance of the structures and especially after recent environmental events in the country