Initiatives at the Urgeiriça mining perimeter were staged according the Master Plan for Environmental Remediation of the Urgeiriça Mining Area, as established under the “Master Study of Radioactive Ore Areas – Phase 2” (EXMIN, 2002/2003).
The most important interventions and activities are listed below:
SLOPE STABILIZATION WORKS, CAPPING AND DRAINAGE OF THE TAILINGS DUMP – PREPARATORY WORKS (2005)
- Erection of fencing around the entire boundary of the area of intervention;
- Cleaning, upgrading/reconstruction of peripheral rainwater ditches system;
- Decanting and adduction of runoff water to the New Dam Sector;
- Execution of access gates for heavy vehicles;
- Execution of wheel cleaning and washing systems;
- Deforestation of the area of intervention with maintenance of a 10 to 15-metre protective strip of trees around the entire boundary;
- Mounting of radiological and dust monitoring devices.
SLOPE STABILIZATION WORKS, CAPPING AND DRAINAGE OF THE TAILINGS DUMP (2006-2008)
- Removal of radioactive waste deposits existing in the Santa Bárbara Spoil Heap (95,000 m³) and in the Poor Ore Spoil Heap (45,000 m³) and their confinement in the Tailings Dump of the Old Dam;
- Flooding of the underground mine to restore the natural hydrodynamic level of the mine water;
- Cleaning of contaminated land in the Industrial Area and Public Areas;
- Cleaning and renaturation of the Ribeira da Pantanha;
- Recovery of Agricultural Land;
- Preparation of the New Dam area for accommodation of materials resulting from clean-up operations;
- Environmental remediation of Shaft 4 and respective wastewater treatment basin.
ENVIRONMENTAL REMEDIATION OF THE VALINHOS FORMER MINING AREA (2004-2008)
- Removal and transport of debris, approximately 6,000 m³, for the New Dam;
- Cleaning and consolidation of underground areas;
- Maintenance and improvement of equipment associated with the Mine Shaft, a piece of heritage to be maintained;
- Rehabilitation of areas subject to cleaning of debris;
- Removal of weeds;
- Deviation of rainwater originating from the area directly surrounding the reservoir, so that it is only fed by the dominant drainage basin;
- Landscaping improvements;
- Fencing off of car access to the leisure area;
- Creation of pedestrian paths;
- Creation of a footbridge for the living area over the water;
Execution of a bridge connecting the reservoir banks;
- Adaptation of existing buildings to support visitors and create a bar/terrace with benches and fixed tables;
- Creation of an access platform for small watercraft.
WORKS IN THE AREAS SURROUNDING THE SPOIL HEAPS AND INDUSTRIAL ZONE (2008)
- Quantification of levels of radioactivity in metallic materials, building materials and other structures of the former industrial area of Urgeiriça;
- Demolition of buildings and structures in the areas surrounding the CTP (Chemical Treatment Plant) and the Santa Bárbara Shaft;
- Movement of contaminated soil, its capping and protection with appropriate materials;
- Landscaping of the intervention area.
BASIC ENVIRONMENTAL REGENERATION OF THE INDUSTRIAL AREA OF SANTA BÁRBARA AND QUINTA DA VITÓRIA AND ROADS AND SLOPES IN PUBLIC AREAS (2011-2012)
- Removal of road materials;
- Final recovery of some local areas for the integration of those areas into the surrounding environment and protection of ecosystems;
- Disposal of around 40,000 m³ of materials from the cleaning of deposits in the Urgeiriça area and around 4,500 m³ of the products resulting from the excavations to be carried out during the contract;
- Preparation of materials reception area through the creation of drainage conditions of foundation lands;
- Creation of a water treatment basin from the existing MWTP;
- Placement of a layer of compacted clay with a thickness of 50 cm across the whole area affected by the intervention.
CONSTRUCTION OF A PASSIVE MINE WATER TREATMENT SYSTEM FOR SHAFT 4 (2012)
- Acceptance and containment of groundwater springs;
- Creation of settling tanks (primary and secondary) and drying bed;
- System for routing of sludge from the settlement tanks to the drying beds;
- Implementation of floating macrophytes and stabilization pond with final discharge;
- Application of seals.
WORKS IN THE RIBEIRA DA PANTANHA AND FINAL SEALING OF THE NEW DAM (INCLUDES VALE CÔVO) (2012-2014)
- Cleaning of deposits scattered around the New Dam area and their packing into the dumping areas;
- Construction of a tailings pond;
- Creating a new renatured bed for the Ribeira da Pantanha which incorporates the river, from a biophysical and landscaping standpoint, into the space of the New Dam;
- Operational maintenance of the entire system of drains and treatment components that are active in the New Dam and that are affected by the river deployment works;
- Permanent closure of the dump areas of the New Dam, final sealing and drainage of those areas and their landscaping.
CONSTRUCTION OF PASSIVE AND ACTIVE SYSTEMS FOR THE TREATMENT OF SPRINGS AND AFFLUENT STREAMS FLOWING TO THE NEW DAM AREA (2015-2016)
- Clearing of intervention areas and demolition of MWTP and ruined buildings;
- Emptying of basins 1 and 2 to the waterline to a depth of around 1 m and dehydration of sludge deposited on the bottom and its routing to an appropriate final destination;
- Cleaning of the waterproofing screens and installation of the floating islands and platforms;
- Implementation of the passive treatment tank and installation of the filling mechanisms, equipment and piping;
- Execution of the lift station for the lagoons and respective eduction pipe;
- Execution of the MWTP;
- Execution of a containment wall for the spring and respective gravity filter to the leachate well;
- Installation of vari-speed drives on the electrical pump sets in the leachate well and existing monitoring station;
- Execution of technical trench and installation of four pumping mains from the leachate well to the MWTP and passive treatment;
- Execution of roads and landscaping;
- Execution of fencing and access gate for the MWTP and passive treatment enclosure;
- Execution of rainwater drainage;
- Execution of electrical installations.
The contract, which is ongoing, begun in 2016 for the “CHEMICAL AND RADIOLOGICAL DECONTAMINATION AND ENVIRONMENTAL REGENERATION OF THE CTW AND BUILDINGS OF THE MINING PERIMETER” will be the last of the final phase of environmental remediation of Urgeiriça and will consist of the following main activities:
- Decontamination of the soil and subsoil inside and around the CTP and buildings of the former mining perimeter;
- Cleaning and decontamination of existing structures and contaminated equipment inside the CTP and buildings of the former mining perimeter;
- Strengthening and adaptation of the structural conditions of the CTP and buildings of the former mining perimeter, as a result of the decontamination works.