The dam that collapsed last Friday at a Vale mining company site that left at least 84 people dead and hundreds of people missing had been certified as safe weeks before the disaster.
In the aftermath of the disaster, more bodies have been identified, said a spokesperson for the southeastern state of Minas Gerais. There are still hundreds people missing as a torrent of water and mud slammed into Brumadinho, in southeastern Brazil.
Over 260 Vale mining company employees are among the missing, a spokesperson said. Vale, the company that operates the dam, is the country’s largest mining company. Vale employees were eating lunch on Friday afternoon when the dam collapsed.
Brazil’s National Mining Agency classified the Brumadinho dam as “low risk” just weeks before its collapse, the agency confirmed to CNN.
The disaster renewed scrutiny of Brazilian mining giant Vale, which was linked to another deadly dam collapse in Minas Gerais less than four years ago.
The breach flooded parts of Minas Gerais and buried most of Brumadinho. Debris spilled into the mine’s administrative area, where employees were working, Vale said.
Officials said they expect to contain the sludgy mine waste known as tailings. The Brazilian National Water Agency said they are monitoring the tailings and coordinating plans for supplying water to the affected region.
Attorney General Andre Mendonca said Vale is responsible for the disaster.
Authorities called the 2015 Mariana dam collapse the worst environmental disaster in the country’s history. The collapse killed 19 people and wreaked havoc on the environment, leading mining company Samarco – a joint venture between Vale and BHP Billiton – to reach a deal in 2016 with the Brazilian government to pay up to 24 billion reals ($6.2 billion).
In a television interview last Saturday Vale Chief Executive Fabio Schvartsman apologized for the incident. He did not, however, take responsibility for it on the company’s behalf: “I don’t know who is responsible, but you can be sure we’ll do our part.”
He also said Vale created a working group that will present a plan to raise the safety standard of the company’s dams.
“It seems to me that there is only one solution: We have to go beyond any standard, national or international. We are going to create a safety mattress that is far superior to what we have today,” he said.
The 86m-high dam holding 11.7 million cubic meters of tailings was built in 1976 by Ferteco Mineração, which was acquired by Vale in 2001, and had been inactive for three years. A decommissioning project was under development.
TUV SUD do Brasil, which performs industrial inspections, last reviewed the tailings dam in September 2018, issuing a “stability condition statement,” which Vale said attested to the “physical and hydraulic safety of the dam.”
The dam also underwent regular field inspections, which were reported to the National Mining Agency (ANM) through the Integrated System for Safety Management of Mining Dams (SIGBM). The last inspection registered on the ANM system took place in December and, according to Vale, didn’t detect any change in the state of the structure.
Vale officials went on to say in a statement, the “Dam went through biweekly field inspections, all of which were reported to ANM (National Mining Agency) through the SIGBM (Integrated System for Safety Management of Mining Dams). The last inspection registered on the ANM system was executed on 21/12/18. In addition, it underwent inspections on 1/8/19 and 22/01/19, and was registered on Vale’s own monitoring system. The registration of each inspection on the ANM, according to legislation, must be executed by the end of the following fortnightly period. All these inspections did not detect any change in the state of the structure.
“The dam had 94 piezometers (an instrument for measuring the pressure of a liquid) and 41 Water Level Indicators to monitor its integrity. The information from the instruments was collected periodically and all their data analyzed by the geotechnitians responsible for the dam. Of the 94 piezometers, 46 were automated.”