Vale SA blocked attempts by Brazilian authorities to audit the tailings dam at its Feijao iron ore mine months before the fatal burst, Reuters reported March 20, citing news website G1, which quoted Minas Gerais state prosecutor William Garcia.

In the report, Garcia said the subpoenas for the review of safety documents were made in June 2018, well before the January incident that claimed over 300 lives.

Lawyers for the mining major reportedly did not provide the dam's safety documents and argued that its stability was validated by its hired auditor TÜV SÜD AG.

The state prosecutor said that TÜV SÜD was used to make it more difficult for prosecutors to investigate, and to conceal from public view the state of the dam.

In a statement, Vale said it fully trusted TÜV SÜD's reports and broader safety measures implemented by the miner that "proved the stability of the dam in accordance with the law" as reasons it asked for the dismissal of the prosecutor's inquiries.

Earlier this month, a report by The Wall Street Journal revealed that Vale rehired TÜV SÜD to complete the safety certification of the tailings dam at the Feijao mine after firing an auditor that refused to certify the dam's stability.

A court in Brazil ordered 11 Vale employees and two contractors who worked for TÜV SÜD to be arrested and charged in connection to the dam burst.