Vale raises alarm of potential tailings dam failure

Tailings dam breaches are an ongoing environmental risk. Image: Vale

Vale has warned of a possible dam collapse at the Gongo Soco mine in Barão de Cocais, Minas Gerais, 65 kilometres away from the site of the Brumadinho dam failure.

Gongo Soco, which has not been active since 2016, showed movement on the northern slope of the mine pit – a possible trigger for a failure at the Sul Superior dam 1.5 kilometres away.

Vale has raised the alert level of the Sul Superior dam from 2 on February 8 to alert level 3 on March 22.

The extraction site of the Gongo Soco mine is now under 24-hour, real-time remote monitoring, which shows the possibility of slide of its north slope, but did not show evidence of deformation process at the dam.

“There is no technical information so far to state that the eventual slide of the north slope at the extraction site of Gongo Soco mine – whose operations ceased in 2016 – will cause the breach of the Sul Superior Dam,” Vale said in a statement.

“But Vale is reinforcing the level of alertness and readiness for the risk of breach.”

About 458 community members from the dam’s self-rescue zone – Piteiras, Socorro, Tabuleiro and Vila do Gongo – had been relocated to a temporary housing rented by Vale.

Vale and the state civil defense carried out dam emergency drill on Saturday, involving around 1600 residents (27 per cent) of the city’s secondary safety zone, which was supported by the civil and military police, the military fire service and the city government.

Iron ore prices have surpassed $US100 ($145) a dry metric tonne CFR China on Friday for the first time this year, hitting the highest level since 2014, according to S&P Global Platts.

The price hike would benefit Australian competitors including BHP, Rio Tinto and Fortescue Metals Group as iron ore deposits from Western Australia are expected to make up for the global deficit.

Production cuts by Vale, the biggest miner of the commodity, are limiting global supplies for iron ore after its complexes were shut following the Brumadinho tailings dam rupture in January.

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