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The Sebastião das Águas Claras tailings dam failure (Nova Lima, Minas Gerais, Brazil)

(last updated 9 Sep 2002)

The dam failure and its impacts

On June 22, 2001, a waste dam of the iron mine of Mineração Rio Verde Ltda failed at Sebastião das Águas Claras (also known as Macacos), Nova Lima district, near Belo Horizonte, Minas Gerais state, Brazil.
The waste was stored in a mined-out open pit.
The slurry wave travelled about 8 km downstream the Córrego Taquaras stream, killing at least two mine workers; three more workers are reported missing.
The mud affected an area of 30 hectares; it interrupted the main access road of São Sebastião das Águas Claras and reached a protected nature reserve.
It is feared that, in case of rain, the mud may be carried further into the Rio das Velhas and might affect the water supply of Belo Horzionte.

The causes of the dam failure

The cause of the dam failure is not known yet.

During their last inspection in May 2001, inspectors of the State Foundation of the Environment (Feam) noted the lack of piezometers required to monitor water pressure and water level in the impoundment.

The aftermath of the dam failure

On June 25, 2001, the National Department of Mineral Production (DNPM) suspended Mineração Rio Verde Ltda's license indefinitely. On July 16, 2001, the suspension was lifted, but only for a dry treatment scheme.

On June 26, 2001, the Secretariat of State of Environment and Sustainable Development (SEMAD) established three working groups to assess the impacts of the dam failure. Their results shall be presented within 30 days.

On June 26, 2001, the State Advice of Ambient Politics (COPAM) suspended Mineração Rio Verde Ltda's environmental license for 10 days.

On June 27, 2001, the Brazilian Institute of the Environment and Natural Resources (Ibama) fined Mineração Rio Verde Ltda. R$ 1.5 million (US$ 0.6 million) for ambient crime.