Aiming to protect the communities and reduce the impact on the environment, Vale is carrying out three impoundment projects in areas downstream of the dams: Sul Superior (Barão de Cocais), B3/B4 (community at Macacos, in Nova Lima), and in the flood spot of Forquilha I, II, III, IV and Grupo dams (community of São Gonçalo do Bação, in Itabirito). The construction work is expected to be complete by early 2020, and the project includes de-characterisation of nine dams, amounting to R$7.1 billion, as announced in Vale's first quarter balance sheet in May. The impoundment structures will be able to retain tailings from dams in an extreme breach scenario. Sul Superior, B3/B4, Forquilha I and III dams are classified at Emergency Level 3. Forquilha II and Grupo dams are classified at Emergency Level 2 and Forquilha IV dam has the Stability Condition Statement, but its operation was shutdown to comply with a request from the Brazil's National Mining Agency that, in February, suspended the operation of Fábrica mine, where these dams are located.
For the B3/B4 dams (at Macacos), the impoundment project - which will be 30 m high and 190 m long - is expected to be complete by December this year. It consists of a barrier formed by rocks (rock-fill) and located 8 km downstream of the dam, just before the road that connects the district of Macacos to the headquarters of Nova Lima. These works will be essential to protect the Rio das Velhas basin and the Water Treatment Plant at Bela Fama, as well as all the Secondary Safety Zones (Honório Bicalho, Rio Acima, Raposos, and Nova Lima).
In Barão de Cocais, emergency work has already been complete, consisting of the installation of two wire mesh barriers and one made granite blocks. These barriers will reduce the flooding speed in case of a breach. But the main works will be a concrete impoundment structure located 6 km downstream of the 36 m high and 306 m long dam, which will also be complete by December.
In the region of Forquilha dams, the impoundment structure will be located 11 km downstream of Forquilha I Dam in Itabirito; it will be 60 m high and 350 m long. The project, which is located in Itabirito, is expected to be complete by January 2020. It is essential to protect the Secondary Safety Zone, which includes - in addition to Itabirito - the municipalities of Raposos, Rio Acima, Nova Lima, and three districts of Belo Horizonte (Jardim Vitória III, Beija-Flor, and Maria Tereza).
Due to the emergency nature, the works were previously communicated to the State Department of Environment and Sustainable Development (Semad, Secretaria de Estado de Meio Ambiente e Desenvolvimento Sustentável) and, within 90 days after notice, the documentation and respective studies will be submitted as provided for in Article 8 of Semad/IEF Joint Resolution No. 1905, from 2013.
To carry out these three projects, Vale is creating access to these areas for the construction sites. The aim of this access is to prevent truck traffic within the surrounding communities, reducing the inconvenience caused to residents during the construction work.
Read the article online at: https://www.globalminingreview.com/mining/20082019/vale-undertakes-dam-construction-work-to-improve-safety-and-reduce-environmental-impact/
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