Basins, toe-drains and walls: A look inside Kennecott’s water collection system

At Rio Tinto Kennecott, we are committed to responsibly managing our resources. We are always evaluating new approaches to be safer, more efficient and minimize our impacts to the community and environment. 

Water collection, storage and treatment remain key areas where engineering and technology are applied for maximum safety and efficiency. In the 1990s, we developed a cut-off wall water collection system to prevent potentially contaminated water from seeping down from waste rock piles and significantly impacting the underground aquifer, a source of drinking water for the Southwest part of the Salt Lake Valley. Cut-off walls are concrete structures built down gradient from the toe of waste rock piles into the bedrock. The cut-off walls stop waste rock contact water from moving farther downstream.  

As part of our work on The Alternative View Construction Project anticipated to be completed by the end of 2028, we have upgraded the mine’s groundwater collection system with enhanced surface and groundwater infrastructure.

The new water collection system includes

  • Cut-off walls.
  • Stormwater basins adjacent to the cut-off walls.
  • Toe-drain system to maximize the capture of water
  • Potential for future separation and management of storm water and water that has come into contact with waste rock. 
  • Measures to reduce the risk of contact water being released into the surrounding environment.

To ensure safety, the new cut-off walls and stormwater basins are engineered and constructed to handle a minimum of a 100-year, 24-hour storm event.

 

Cut-off wall under construction

One of the twelve new stormwater basins built

Toe-drain under construction

 

A total of 11 cut-out walls and 12 stormwater basins were built as part of the project, along with the installation of an 11,700-feet toe drain.