Panatanha stream re-naturalization and Urgeirica's new tailings dam
: Re-naturalization of the stream's original bed. Environmental recovery of the hazardous ore tailings of the Urgeiriça Mine, by reconditioning, slope stabilization, sealing with liners, drainage and monitoring of the backfills of the tailing dam, involving mining ore tailings with a high concentration of heavy metals and radioactive elements. Landscape rehabilitation.
A continuous monitoring system has been implemented that measures the volume activity of radon in the soil at six sites at different depths and hence also the effectiveness of the sealing materials used to prevent radon diffusion into the atmosphere, to assess the effectiveness of the technical remediation solution used at the Urgeiriça Old Tailings Dam (EC, 2012).
Improved water quality
Yes, the main objective of this project is to improve the river water quality through the stabilization and drainage of radioactive ore tailings and restoration of the stream's original bed (LCW Consult, s.a.). A continuous monitoring system has been implemented in the former Urgeiriça mine. Surface water is monitored upstream and downstream of the former uranium mine with different frequencies: upstream waters are monitored biannually and downstream waters quarterly to assess pH, temperature, conductivity, Eh, Cl-, Mn2+, Ca, Na, Ra-226, total U and SO42-, defined as indicator parameters (EC, 2012).
Biodiversity conservation or increased biodiversity
Yes, restoration of river habitat heterogeneity can enhance retention and decomposition of organic matter, key ecosystem properties underpinning ecosystem functioning and service delivery (Frainer et al; 2017).
Yes, restoration of the stream's original bed and 19 ha landscape rehabilitation (LCW Consult, s.a.).
Increased quality and quantity of green and blue infrastructures
Yes, through the stabilization and drainage of radioactive ore tailings and restoration of the streams original bed (LCW Consult, s.a.).
Yes, through the remediation and rehabilitation of the radioactive ore tailings, landscape rehabilitation and the establishment of the facilities necessary to carry out continuous monitoring of the levels of radioactivity in air, water and soil and to ensure compliance with the Basic Safety Standards (EC, 2012; LCW Consult, s.a.). A total of 19 ha of landscape has been rehabilitated (LCW Consult, s.a.).
Improved aesthetic value
Provision of health benefits
Yes, through stabilization and drainage of 165.000m3 radioactive ore tailings and continuous environmental monitoring (LCW Consult, s.a.).
Low water quality
According to the Commission experts visit in 2006 , groundwater percolated the interior of the old mine and the nearby mill tailings where it could interact with the geological materials present, inducing a transfer of chemical and radioactive elements from solid into the liquid phase. The resulting waters were acidic and liable to transfer significant amounts of dissolved metals and radionuclides into the environment (acid drainage). (EC, 2012). Tthe river has shown low water quality due to the presence of radioactive ore tailings.
This project is focussed on remediation and rehabilitation of the Urgeiriça tailings but also includes environmental remediation of the mine's industrial area where the remains of the former milling and processing plants are located (plus the two deposits of ore and waste rock respectively). Furthermore, all the waste arising from the industrial area would be transferred to the tailings. (EC, 2012).
Low aesthetic value
Negative environmental impacts on human health
Yes, the tailings waste consisted of geological material containing hazardous chemical and radioactive substances and, if left as such, would be exposed to external geodynamic processes that would be liable to transfer these substances into various environmental compartments (acid drainage following the percolation of rain and/or groundwater; dispersal of dust; emanation of Radon and progeny). In 2006 the dose equivalent rates measured on the tailings varied with the location and in some spots reached up to 25 µSv/h while the radiological background of the region typically varies between 0.2 and 0.7 µSv/h (Urgeiriça, Quinta do Bispo, Bica and Senhora das Fontes). The environmental remediation of the tailings at the Urgeiriça mine was declared to be of top priority within the national plan for the rehabilitation of former uranium mining sites in Portugal. (EC, 2012).
Good health and well-being (SDG3)
Clean water and sanitation (SDG6)
Yes, one of the project objectives is to decontaminate the river.
Sustainable cities and communities (SDG11)
Aquatic biodiversity (SDG14)
Yes, besides the restitution of the stream's original bed, this action focuses on stabilization and drainage of the radioactive ore tailings which may benefit aquatic biodiversity.