Environmental Remediation of the Vale da Abrutiga Mining Area

Location

Tábua (Municipality)

Investment

2,107,626.55 €

2007 - 2008

Environmental Remediation of the Vale da Abrutiga Mining Area

Concluded

The former mining area of Vale da Abrutiga is located in the civil parish of Ázere, in the municipality of Tábua and district of Coimbra. Locally, the mine is located on a steep slope to the SW, near the Reservoir of the Agueira Dam, with the elevations varying, at the mine site, between 200 m and 120 m on the Reservoir banks. There are no demographic and agricultural pressures on the site and its immediate surroundings are heavily forested with eucalyptus.

The mining operations consisted of the opening of an open pit with three-metre-high steps. Around 83,695 tons of ore were extracted with an average U₃O₈ content of 0.11%, which produced 94,903 kg of U₃O₈. This open pit has an area of 32,000 m² and, in 2001, environmental rehabilitation works were begun (Phase 1) which consisted of refilling the open cut with around 180,000 tons of poor ore, after treatment (neutralization and precipitation of ²²⁶Ra) of the acidic water accumulated therein, thus avoiding further accumulation of water and acidification inside the open cut. The volume of excavation still available was 484,000 m³. The mine was fenced off with wire and is duly signposted.

The intervention in this mining area took place in two stages, whereby, during the first stage, between January 2007 and April 2008, all mining heap materials were confined by removing and compacting them into the open cut. The second stage of the intervention began on 3 June 2008, with the lining, drainage and landscaping of the mining heap. The work carried out comprised the following main activities:

Excavation of the poor ore and its placement in a dump, which includes the removal, transport and disposal with compaction in the open cut of the poor ore mining heap, according to a sequence defined by the radioactive materials;
Excavation of the remaining material and its placement in a dump, which includes the removal, transport and disposal with compaction in the open cut of the remaining material, with lower levels of radioactivity;
Lining, drainage, access road and restoration of the landscape, which includes the execution of the final cover system, the installation of the drainage system, the installation of piezometers for monitoring, the execution of an access road and revegetation work.

This work was awarded to the consortium Tecnovia – Sociedade de Empreitadas, SA / LTO – Lavouras e Terraplenagens do Oeste, Lda. for an amount of € 2,107,626.55 and had a duration of 300 days.

The investment was co-financed by the Environment Operational Programme under the Third Community Support Framework, and allowed the correction of the geotechnical instability of the slopes of the spoil heap, as well as the resulting visual impacts, proper handling of the existing surface acid mine drainage and in improvement of the safety conditions for the circulation of people and animals.