Mine waste management must be at the forefront of mine planning in Europe – particularly in the UK, EU member states and countries undergoing accession to the EU. This is not only motivated by legislation and standards, but also by communities neighbouring or overlooking sites who have the right to give input to relevant approval decisions.
Topping the list of reasons are strict water quality criteria for rivers and groundwater. The criteria are not only set at EU and national levels but also at river basin and sub-catchment levels. Together with the geochemistry of waste, these criteria will determine options for waste disposal. For example, whether using the waste in backfill is possible and whether lining or capping of surface facilities may be required.
If cyanide is used in mineral processing, then a highly reliable cyanide detoxification process must be used to treat tailings. The acceptable level of cyanide in tailings storage facilities in the EU is five times lower than the limit given in the International Cyanide Management Code. Cyanide limits in downstream courses are even stricter; the limit for cyanide in rivers in the UK is 20 times lower than in this Code. EU legislation also requires all waste to be formally classified.
Depending on the waste geochemistry, small amounts of seemingly benign material can sometimes trigger a ‘hazardous’ classification. While associated design and management requirements are relatively straight forward, the notion of a hazardous waste facility in a rural setting can create delays in the permitting process.
Another challenge is pressure to minimise both visibility and footprint areas of surface waste facilities. Landscape impacts and abundant sites of conservation importance must influence location selection and will constrain the scale of structures. Technologies that hugely reduce the size of facilities, such as dry-stacking, become more attractive under these conditions. Design of waste facilities so they mimic surrounding landforms is essential in some jurisdictions.
Fear that mine waste facilities will fail is at an all-time high, so stakeholders need to have high confidence in the integrity of the facilities. Furthermore, it can’t be assumed that recognised international standards, such as those of the Canadian Dam Association and Australian National Committee on Large Dams, will be sufficient to meet all required design criteria. Designers must ensure they understand EU guidance, applicable national legislation, as well as internationally recognised guidelines.
Finally, a mine waste facility’s siting can influence the applicable legislation and taxes. If it is remote from the mine site, it may not be legally recognised as a mining facility. In this case, slurry disposal of waste may not be allowed, and high landfill taxes could apply. These taxes can be greater than 100 USD per tonne.
