As the mining sector maintains its compliance with the Global Industry Standard on Tailings Management (GISTM), the value of water stewardship principles can be seen throughout various aspects of this standard.
A key aspect of water stewardship's contribution to responsible tailings management is its focus on the water footprint of the mine and Tailings Storage Facilities of (TSFs) - viewed beyond the mine's license area and into the broader water catchment area (basin), according to Lindsay Shand, Partner and Principal Environmental Geologist at SRK Consulting.
"Mines will often develop their Water Management Plans (WMPs) with a limited focus on the area within the mine's boundaries", says Shand. "This goes only part of the way towards achieving the real goal of these plans, which is to mitigate operational risk and protect the environment".
She highlights that a water stewardship approach broadens a mine's appreciation of factors outside its immediate influence, which needs consideration when managing water responsibly. The approach emphasises proactive and ongoing collaboration among water users within a catchment, ensuring their operations and plans are more holistic and sustainable.
"This aligns well with the GISTM's requirements that call for more effective engagement and collaboration between mines and their stakeholders", she says. "Such engagement applies to water-related among a range of others".
Conserving Clean Water Resources
The location and design of many TSFs take advantage of valley topography to facilitate the storage of tailings material, says Shand. Low-lying valleys assist with this slurry containment and offer convenient side walls for a TSF. However, Valley are typically associated with river systems, so this has meant that TSFs are often in close contact with freshwater resources.
“These valley locations are generally weak points’ in geological terms, as there may be a contact zone between two different rock groups or a fault or fracture zone within a geological unit”, she explained. “This may, and often does, create a connection between the surface water and groundwater”.
This means that locating a TSF in such a position raises the risk of surface contamination reaching groundwater systems. Various engineering controls, such as upstream diversion channels, are placed to keep clean water separate from the dirty water. The challenge is that these controls need to be effective into perpetuity..
