Location
Grândola (Municipality)
Investment
4,840,521.75 €
2010 - 2015

Environmental Remediation of the Lousal Mining Area

Concluded

Lousal Mine is located in the civil parish of Azinheira dos Barros and São Mamede do Sadão, municipality of Grândola, district of Setúbal and covers an area of around 30 ha.

The deposit was recorded in 1882, and the concession was awarded in 1885 to mining engineer Alfredo Mansson, who remained there until 1889. In 1890, Waldemar D’Orey obtained the first operating permit, with rights to operate the mine being granted to the company Mina dos Barros in 1910. In 1915, Henrique Burnay e Ca bought the concession, which was transferred in 1934 to the Société Anonyme Belge des Mines d’Aljustrel. In1936, operation of the mine was transferred to the Sociedade Mindes et Industries SA and, in May 1988, the last few tons of pyrite were extracted.

The operations were performed via open pit and underground mines. In the southern and central areas of the deposit, average contents of 45 to 50% sulphur and 0.7% copper, proportions that varied towards the NW, where the content was around 39% sulphur but with relatively high values for copper, lead and zinc. Gold content was around 1g/ton and silver, 2 g/ton.

The former mining area of Lousal has the subject of two major environmental recovery operations.

The first, in 2010/2011, consisted of modelling and preparation of a pyrite landfill, vertical waterproofing of the Dam Area, drainage of water with the construction of rainwater collection and leaching water collection ditches, an acid water treatment system, with the construction of wetlands located downstream of the cementation cells; construction of fences and footpaths; placement of topsoil; modelling of the tailings heap and sealing of galleries. This contract was awarded to the consortium Tecnovia – Sociedade de Empreitadas, SA / LTO – Lavouras e Terraplenagens do Oeste, Lda. for 1,801,253.20 and had a duration of 365 days.

The second, in 2014/2015, consisted of the sealing of shafts and tunnels; execution of a leachate and aeration channel; evapotranspiration dams; installation of fences and safety signs; construction wetlands and aeration channels; installation of fencing and signage in the wetlands; construction of stream wetlands; revegetation, and finally, the implementation of a surveillance, control and monitoring plan. This contract was awarded to FR3E – Energia e Novas Oportunidades, Lda. for 1,803,959.81 and had a duration of 365 days.

The investments were co-financed by the Cohesion Fund and allowed the environmental liabilities resulting from mining at this location to be resolved, bringing benefits to local populations through the improvement of current conditions and use of the areas reclaimed for other ends.

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