Mining generates waste which has the potential to lead to negative impacts.
The threats associated with the waste generated include acid mine drainage during and after site operation, heavy metals leached from wastes and concentrates around the site, leaking of mercury (if used in the process, or from ores) and cyanide (if used in leaching processes), and air pollution caused by dust emissions as a result of mining activities such as drilling, blasting or from dry surface areas of tailings storage facilities.
Mining companies should identify, assess and control sources of potential pollution and their impacts on human health and the environment. They should also apply the mitigation hierarchy to control sources of potential pollution.
What is the mitigation hierarchy? What areas of risks does the mitigation hierarchy address?
The mitigation hierarchy is a framework used by industrial sectors to guide their activities toward managing risks and limiting negative impacts. It is often associated with biodiversity, but it can also be applied to general environmental and social risk assessments. An objective under IFC Performance Standard 1: Assessment and Management of Environmental and Social Risks and Impacts is:
To adopt a mitigation hierarchy to anticipate and avoid, or where avoidance is not possible, minimise, and, where residual impacts remain, compensate/offset for risks and impacts to workers, affected communities, and the environment.
In this context, the mitigation hierarchy comprises five broad stages that are designed to be implemented sequentially.
- As a priority, avoid the production of waste at the source. This is the environmentally preferred strategy.
- Reduce the amount of waste or pollutants generated. This is also a preventive step.
- Re-use waste materials as far as possible.
- Recycle by reprocessing waste materials to produce another product.
- Dispose of the waste products after going through or exhausting the options above.