Mine Tailings Storage: Safety Is No Accident

Mine closure considerations Planning for safe closure

Required outcome

Physical stability of the site - tailings storage facilities, roads, buildings, etc. must not pose any hazard to public health and safety; engineered structures must not deteriorate or fail; erosion from the site must not adversely impact surrounding terrestrial or aquatic environments. Geochemical stability - harmful materials must not leach from or erode the site; surface waters and groundwater must be protected against contamination. Land use - the closed mine site should be rehabilitated to pre-mining conditions or conditions that are compatible with the surrounding land or achieve an agreed, alternative, productive use of the land. Sustainable development - elements of mine development that impact the sustainability of social and economic benefits, should be maintained and transferred to succeeding custodians.

Protect public health and safety.

Alleviate or eliminate environmental damage.

Make productive use of the land, return it to its original condition or find an acceptable alternative.

As far as possible, ensure sustainability of social and economic benefits resulting from mine development and operations.

Source: adapted from Robertson and Shaw (2002)

Table 3. Mine closure

Managing for mine closure – perpetual management

Planning for tailings storage-facility management after mine closure should be an essential component of mine planning. Best practice requires that it should commence before the start of mining and be continually updated throughout the life of the mine until final closure. Proper post-closure management of tailings not only safeguards communities and the environment, but also makes good business sense by avoiding costly future remediation and compensation. Mine planning must take into consideration the long-term physical, chemical, biological, social and land-use characteristics of the area surrounding the mine. The extent of the mine footprint needs to be carefully determined prior to mining. The poor performance of post-closure management of tailings is one of the drivers for governments imposing significant final rehabilitation commitments on mining companies before mining projects are approved (LPSDP 2016). There are too many examples where problematic mining operations have been abandoned or offloaded by those responsible, leaving the regulators and community to clean up. In the worst cases, clean-up is not even attempted, and mines are abandoned and continue to release pollutants into the environment. Impacts of mining waste on biodiversity The impacts of tailings dam failures on biodiversity can be both immediate and long term (Figure 17). When large volumes of tailings enter waterways, the material can have

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