Remains of Samarco's Collapsed Dam Unstable Because of Heavy Rains

RIO DE JANEIRO—The ruins of a waste-storage dam that collapsed at a Brazilian mine in November have become unstable due to recent heavy rains, mining company Samarco Mineraç ã o SA said Wednesday, raising concerns about a possible aftershock to the country's worst-ever environmental disaster.

Samarco said it detected "a movement" in the remains of its destroyed Fundã o dam on Wednesday afternoon, prompting an evacuation of employees who were in the area. Local emergency-response authorities have been alerted, the company said.

Additional information wasn't immediately available. The company said its other two dams in the area, Germano and Santaré m, remain stable and are being "continuously" monitored.

The Fundã o dam's sudden failure on Nov. 5 released an avalanche of muddy mine waste, known as tailings, that killed at least 17 people, wiped out a number of settlements and polluted more than 400 miles of rivers. Samarco, a joint-venture between Brazilian mining giants Vale SA and BHP Billiton Ltd., faces a criminal investigation and civil suits totaling some $5 billion.

The company was widely criticized in the wake of the accident for having lousy contingency plans. Residents of the nearest village, Bento Rodrigues, say they were alerted to the dam break by word-of-mouth and barely had time to evacuate before the mud came. An engineer who worked on the dam said earlier this month that he had alerted Samarco to serious problems more than a year in advance, an allegation the company challenges.

In the weeks following the disaster, Samarco had been working to stabilize Germano, which is larger than Fundã o, and Santaré m, which is located downstream, amid concerns they were damaged by the break. The movement detected Wednesday was between these two dams, Samarco said.

Write to Paul Kiernan at [e-mail]

(END) Dow Jones Newswires

January 27, 2016 15:55 ET (20:55 GMT)

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