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Mount Polley Mine Tailings Pond Breach (B.C.) and Environmental Changes








The multidate composite (image in red) has been created from two Landsat-8 satellite images captured on July 29 (before the event) and August 5, 2014 (after the event).

The two captured images were then superimposed to better illustrate the environmental changes (before and after the event) due to the tailings pond breach at Mount Polley Mine in British Columbia.

Environmental changes are visible in red (see legend for more details):



  1. Retention basin is emptied of its water and part of its tailings
  2. Breach in the retention basin dike
  3. Section of forest destroyed by the flow of water and mud
  4. Wetlands covered in mud
  5. Part of Polley Lake containing a high concentration of suspended matter
  6. Part of Polley Lake containing an average concentration of suspended matter
  7. Flow of mud has widened the bed of the Hazeltine River to one hundred metres or more
  8. Plant debris (trunks) carried away by the flow of water and mud