Environmental Remediation in the Freixiosa Mining Area

Location

Mangualde (Municipality)

Investment

368,995.82 €

2011 - 2012

Environmental Remediation in the Freixiosa Mining Area

Concluded

The former mining area of Freixiosa is located in the civil parish of Freixiosa, municipality of Mangualde and district of Viseu.

Underground mining ended in 1982 with only one floor used to a depth of around 50 m, with operations being later transferred to open pit mining until September 1984, in an outcropping of the seam zone, 200 m to the NNE of the master shaft. The cumulative production of this mine was 84,181 kg of U₃O₈, contained in ores with an average U₃O₈ content of 0.14%. That figure includes open pit production estimated at 23,265 Kg of U₃O₈ and a lower ore content of 0.118% of U₃O₈. The mine shaft is closed with a slab of concrete and the open pit has been filled. There was no use of chemical leaching at the mine.

The environmental remediation work at the Freixiosa mining area consisted of the following main activities:

Fencing off and clearing of the intervention areas (South and North);
Demolition of existing structures (buildings and masonry structures);
Removal of materials from the spoil heap and contaminated soil adjacent to the former mining area of Quinta do Bispo;
Covering areas drained to variable thicknesses with sandy-silt soil, according to the cut-and-fill plan (North zone) and, in the south zone, in which radiometric values greater than 250 cps (counts per second) were identified in an average thickness of 0.50 m, ensuring the attenuation of the radiation to values less than 250 cps;
Cleaning and adjustment of the water line downstream of the gallery, with transport of all materials to the former mining area of Quinta do Bispo;
Execution of a water treatment system for water springs in the northern zone, near the recovered former open pit mine;
Sealing of shafts;
Landscape restoration, which consisted of the implementation of seeding/planting plans and signage (respectively promoting reductions in the erosive effect on the intervention areas, with their integration into the surrounding landscape, and maintenance of mining memory at the site).

This contract was awarded to Construtora Abrantina, SA for € 368,.995.82 and had a duration of 90 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.