BRASILIA – The death toll after the rupture of a mining dam in Brazil rose to 84, according to Civil Defense of Minas Gerais, as mining giant Vale announced that moves to dismantle similar structures would hit production.

Flavio Godinho, Civil Defense spokesman in Minas Gerais, said the death toll had increased from 65 to 84, while the number of missing fell from 292 to 276.

The disaster struck Friday at Brumadinho dam near the city of Belo Horizonte in Minas Gerais state (in southeastern Brazil), spewing out millions of tons of muddy trailings – a waste byproduct of the iron-ore mining operations – that engulfed buildings, vehicles and roads with a deep, treacherous layer.

Dozens of helicopters and earth-moving machinery were being used in the rescue operation at the site near the town of Brumadinho, in Minas Gerais state.

State governor Romeu Zema said there was little chance of finding people alive.

It is not clear what caused the collapse of the dam, owned by Brazil’s largest mining company, Vale.

Brazilian President Jair Bolsonaro flew over the devastated zone, but said nothing to reporters when he returned from the flight.

Difícil ficar diante de todo esse cenário e não se emocionar. Faremos o que estiver ao nosso alcance para atender as vítimas, minimizar danos, apurar os fatos, cobrar justiça e prevenir novas tragédias como a de Mariana e Brumadinho, para o bem dos brasileiros e do meio ambiente.

— Jair M. Bolsonaro (@jairbolsonaro) January 26, 2019

Instead, he tweeted that it was “difficult to not be emotional before this scene.” All was being done to care for survivors and “determine the facts, to demand justice and prevent new tragedies,” he added.

The military said it was deploying 1,000 troops, including sniffer dogs, to the affected zone under orders from Bolsonaro.

Vale has been shaken by the disaster, the second in three years it has suffered in the same state.

Another dam administered by Vale and Australian mining company BHP Billiton collapsed in 2015 in the city of Mariana in Minas Gerais state, resulting in 19 deaths and forcing hundreds from their homes.

Two hours after the Friday’s accident, its stock fell 10 percent on the New York Stock Exchange.