Vale employees and engineers responsible for the report on dam safety leave the chain | New

The five prisoners left the penitentiary in the Belo Horizonte metropolitan area around 4:30 pm, with their faces covered. Coming first are the three Vale employees: César Grandchamp, Ricardo de Oliveira and Rodrigo Gomes de Mello. Then the engineers of TÜV SÜD Makoto Mamba and André Ybaduda. They had been waiting since Tuesday (5) to leave prison.

According to the decision of the Superior Court of Justice, the release of the five is justified because they all made statements, in addition to having already made searches and seizures and not to have detected the risk that They could offer to society.

The working group responsible for determining the rupture of the Vallée dam crosses the information obtained in the testimonies in order to define the next stages of the investigation. TÜV SÜD engineers are considered key parts of the investigation, especially after one of them, Makoto Namba, told the police that Vale had pressured him to release the statement of claim. stability of the dam that had collapsed.

According to investigations, TÜV SÜD holds consultancy contracts for 31 Vale dams.

During the testimony, the delegate read e-mails exchanged between Vale's employees responsible for the dam, TÜV SÜD and a third company. The messages began to be exchanged on January 23rd. The dam broke out on January 25, two days after the first message.

The survey shows that the subject of the messages "concerns divergent data obtained by reading the automated instruments of January 10, 2019 installed in the dam, as well as the non-functioning of sensors that measure the pressure of the 39, water. "

Makoto Namba stated that he was only informed of changes to the data provided by the sensors after the dam broke.

Jornal Nacional also had access to the testimony of the three Vale employees. The geologist Cesar Augusto Grandchmap said that in mid-June 2018, deep horizontal drains had been installed and that when 14 drains had already been installed, it had been found that the water inserted through the drain located at the foot of the dam did not return, which increased the pressure. in the structure of the 15th drain, which could cause an erosion of the path traveled by the water. He said that measures had been taken to remedy the incident, that some piezometers, a device to measure the pressure of water, could vary up to four meters, but that two hours later, they had returned to normal and that, therefore, the incident had not occurred. clbadified as an emergency. Then TÜV SÜD technicians installed monitoring instruments on the dam. He also asked several technology providers to present solutions for the vertical drainage of the B1 dam. He said he received about seven proposals that reached him in January. Seven months after the incident.

In another extract of the testimony, he stated that he read in his email an abnormal piezometer on January 10, 2019. And that it is not normal that a reading of it made on the 10th arrives on the 25th without an evaluation or an effective action being undertaken.

The working group states that there are several signs of excess water in the tailings pond. A video, for example, shows an improvised barrier to prevent the entry of water from the source to the body of the dam. According to the researchers, it should go through the side of the structure and pour the water at another time. Except that the pipe was cracked and was leaking.

According to the survey, a satellite photo showing a small pond above the tank would indicate a lack of drainage.

There was a lot of rain in the search zone on Thursday (7) and, as a result, there was no overflight with helicopters. Firefighters walked the area on foot and used machines.

Vale stated that it conducted internal evaluations and found that the messages were reserved for members of the company's local technical and operational staff. That is, according to Vale, these messages have not been sent to higher levels. According to the company, preliminary badessments indicate that the differences in the piezometers were corrected after reconfiguration of the equipment, which returned to normal.

Vale also stated that, in the coming days, it is planned to have a complete evaluation of the piezometers done by external experts. According to Vale, no increase in the water level in the dam mbad has been recorded. But, yes, a reduction in the level in the main section of the structure. And that after the installation of deep horizontal drains, an independent company conducted an inspection and no abnormalities were detected.