In the context of action C1, the Sustainability Accounting and Optimization team of BETA Technological Centre (Uvic-UCC) has performed the preliminary assessment for the environmental sustainability of DEMINE technology. This evaluation was developed under the Life Cycle Assessment (LCA) framework and followed the criteria established by ISO 14040 and ISO 14044. The main objective of the LCA was to quantify, evaluate and compare the environmental performance of the DEMINE Mining Effluent Treatment Process (METP) for the Wales demonstration site (Frongoch) in front of a scenario of non-treatment.
This cradle to gate assessment comprises a complete inventory of materials and energy inputs needed for the construction and operation of the DEMINE METP, the waste generation, and its subsequent final disposal, including transportation. The METP process is designed as a larger stand, a chemical-free process; subsequently, the only chemical inputs are the cleaning substances. All inventoried results are then characterized for the 14 impact categories recommended by JRC from the product environmental footprint initiative (PEF). Especial attention is given to the impact categories such as climate change (CC expressed in [kg CO2-eq.]) and freshwater ecotoxicity (FEtox expressed in [CTUe]).
At abandoned mines, the most likely scenario is no power available, so an off-grid solution is needed. Currently, Off-grid power is provided by a generator installed in the ‘Support container.’ It is in the objectives of DEMINE project to power the METP with renewable sources. Different options are under evaluation, with wind and mini-hydro schemes displaying the most optimal results. And the latter being the most suitable one for Wales configuration. Hence, a scenario with only green energy consumption was analyzed.
Preliminary results indicate that climate change and freshwater ecotoxicity impact categories represent a possible trade-off in environmental burden that can occur when dealing with abandoned mine effluents. By treating the effluent, some greenhouse gas emissions arise. Still, on the other hand, the metal removal from the METP reduces in more than 95% the possible ecotoxicological impacts. Furthermore, in the scenario that considers only green energy, the trade-off can be reduced up to 90% of the impacts of CC.
Deployment at both sites is essential to demonstrate the treatment process’s general character, illustrating that the technology can potentially be applied to different mine effluents. The technical, economic, and environmental feasibility of the METP will be demonstrated, using actual operational conditions and accounting for temporal variation of environmental conditions and the mine wastewater composition.
