The company said that the closely watched mound at a Brazilian iron ore mine, operated by Vale SA, began to creep slowly to the bottom of the mine, reducing fears that a sudden landslide would cause a dangerous dam collapse.
The authorities initially feared that a landslide at the Vala mine in Gongo-Soko could destabilize the nearby Sul Superior dam, causing damage to the neighboring city. However, the dam remains intact, Vale said.
The Minas Gerais State Environmental Protection Representative previously estimated the 10–15% chance of losing the integrity of the Sul-Haute dam due to earthquakes from an expected landslide.
This led to the fact that the nearby town of Barao de Kokais is on high alert: officials are conducting an evacuation exercise to avoid a repetition of the tragedy at a distance of about 40 miles (64 km) in the town of Brumadinho, where the January dam broke through, releasing a flood of dirt that killed over 240 people.
Warnings about another possible dam collapse highlighted concerns about the stability of the tailings at Valais as a whole, after two fatal accidents that took just over three years attracted the attention of the world's largest iron ore miner.
The catastrophe at the Brumadinho dam and the subsequent closure of the mine in Brazil prompted Vale to lower the estimate for iron ore sales for the year, pushing prices to record highs.
The dam of the Gongo Soco mine contains about 6 million cubic meters of mine waste, which is about half as much as was released when the Brumadinho dam was broken. Like Brumadinho, the dam at Gongo Soko was built using upstream technology, which is considered the cheapest and least sustainable type of tailing pond.
Weil said on May 18 that it was unclear whether a landslide in the Gongo Sotso mine would lead to the destruction of the dam. However, the company decided to build a concrete structure 6 km downstream to help prevent a fall due to a possible dam break.
Shares of Brazil listed on the stock exchange jumped 2.8% in the news, after which they immediately rose. Shares fell 0.7% at noon, while the Brazilian base index Bovespa rose 0.15%.
