Norsk Hydro A.S.A. reported the results of the expert panel tasked with reviewing the issues that led to the state government mandating the closure of half the refining capacity of the Alumina do Norte do Brasil S.A. (Alunorte) refinery in northern Brazil.
The select panel returned three key findings: first, an overflow occurred from a wastewater-holding pond into an internal open drain known colloquially as Canal Velho. This overflow was in addition to a prior rainwater release in the area.
Second, a power failure on February 17 resulted in the release of diluted caustic soda within the Alunorte refinery. This caustic soda combined with rainwater at the plant on its way to the wastewater-holding pond, which subsequently drained into Canal Velho.
Finally, though there was certainly an overflow from the wastewater-holding pond, the team could find no evidence of leaks or overflow from bauxite residue deposit areas.
The team went on to say that cracks were discovered in a pipeline leading from the DRS1 deposit area to a water-treatment station, but a containment box has evidently captured all leakage so far before it reached the surrounding soil.
According to Hydro, authorities from the Brazilian state of Pará have ordered Alunorte to undertake repairs within 48 hours, and the firm indicates that it has followed the order.
Hydro’s President & CEO Svein Richard Brandtzæg says that the findings do not represent the final word on the situation, but that the firm will continue to take corrective action as necessary.
“The preliminary findings from the internal task force show that we do not have the full overview of the situation and the course of events. I will evaluate the situation thoroughly and revert with more information in due time.”
Hydro says it expects to deliver the full report, along with a separate independent review currently being carried out by an environmental consultancy, in early April.
Beginning production in 1995, Alunorte is the world’s largest alumina refinery. Boasting a nameplate capacity of 6.2 million metric tons per annum, the plant supplies alumina to buyers in Brazil, the Middle East, North America, and Europe.