Linkan Engineering was commissioned to assist Alexco Resources and the United States Environmental Protection Agency (USEPA) in responding to the Gold King Mine portal blowout near Silverton, Colorado. This famous incident severely impacted the majority of the lower Colorado River in late 2015. This flow resulted from an abandoned mine portal that was abruptly opened allowing acid mine drainage (AMD) stored within the mine to discharge into the river system.

Linkan was commissioned to utilize our extensive understanding of AMD water chemistry to optimize the temporary water treatment facility. Special consideration was given to influent water chemistry and modifications to the lime treatment system to optimize treatment for this low pH water. Major improvements were made to solids dewatering systems affording significant cost savings for ultimate disposal.

Iron-based solids are captured from the treatment plant underflow by geobag filters. These consist of geomembrane sewn into a large diameter tube providing a cost-effective solids separation device for properly conditions solids. Linkan conducted the bench testing to identify optimal solids conditioning chemicals that provided rapid filtration through the geobags. Linkan then piloted the optimized system with pilot-scale geobags to identify operational parameters.

Linkan’s unique approach provided rapid and cost-effective resolution of treatment plant operational issues. The recipe for rapid solids separation was utilized by USEPA to increase solids content of geobag-retained solids and greatly reduced space and hauling considerations.

Project Highlights
  • Mobile response to isolated location
  • Entirely self-contained pilot equipment
  • Optimized chemistry for feed water options
  • Optimized chemistry for clarifier underflow solids separation
  • Pilot tested geobag operation parameters
Project Duration


Linkan’s Role
  • Process Development
  • Bench Testing
  • Pilot Testing
  • Solids Handling