With a growing demand for mineral resources, mining activities are increasing on a national and global scale. One of the most important environmental issues and economic burdens of industrial mining is the safe disposal and storage of the large amounts of produced waste. Traditionally, tailings have been stored in land dams, but in Norway submarine tailing disposal (STD) has been practiced for production sites located near the sea.
Produced after the extraction of the target mineral, mine tailings occur usually as fine-fraction slurry and can account for up to 99% of the ore. When discharged the tailings will settle and smother the seafloor, thus directly impacting the benthic fauna over an area close to the discharge point. Although care is taken to ensure rapid sedimentation and reduced dispersal, organisms in the water column may be affected by the presence of fine-grained tailings (FGT) and/or metals dissolved from the tailings.
At present no clear guidelines exist for the practice of STD and there is a need for appropriate experimental and modelling tools to assist policy makers and the industry in environmental risk assessment and to develop guidelines for the practice of STD. The SINTEF DREAM model was originally developed to simulate discharges on the seafloor. By adding a new model for turbidity flows, the DREAM model will better predict discharges occurring on a slope close to shore.
MERIT aims to address knowledge gaps on the environmental fate and effects of STD and to develop an environmental risk assessment (ERA) modelling tool through:
- Increasing our understanding of the fate of subsea mine tailings deposits in fjord ecosystems through detailed characterization of depth profiles and mine tailings collected in-situ.
- Developing experimental systems for exposing organisms to mine tailings to identify the main drivers for toxicity
- Increasing the applicability of the existing SINTEF DREAM-model to predict spreading of mine tailings in fjord systems and in the deep sea.