The mining industry is the second largest generator of waste in the EU after construction; mining accounted for 29% (0.73 billion tonnes) of the total waste generated in the EU in 2012. Mining activities may cause serious social and environmental damage to their surroundings, with considerable impacts on aquatic ecosystems. Developing country governments often lack adequate regulations and monitoring capacities to ensure social and environmental well-being.
One of the most pollutant and dangerous wastes produced in mining activities are heavy metals. Through the extraction and subsequent mineral processing, metals and metal compounds become chemically more available, which can result in the generation of acid or alkaline drainage that flows into aquatic ecosystems. Another major issue caused by mining activities is the high amounts of salts released in these water bodies. Large quantities of potash salts are extracted each year for the manufacture of agricultural fertilizers. During the manufacturing process of crude salt huge amounts of solid residues are stockpiled. The salts are dissolved during precipitation events and may enter the waters bodies.
These mine effluents discharges into the aquatic ecosystems can generate several negative environmental impacts, which can be extremely difficult and costly to address through remedial measures. Moreover, the consequences continue long after mining operations have ceased, leaving a legacy that may spread into the surrounding environment. Abandoned and closed mines are a major contamination concern, as reflected by the Mining Waste Directive (2006/21/EC) requiring the risk-based inventory of closed and abandoned mine waste sites.