Oxygen diffusion in saturated covers

A major environmental concern of the mining industry is the management of mine tailings. Mine tailings are the sulfide mineral by-products of ore beneficiation. Exposure of mine tailings to both water and oxygen cause acid-generating reactions to occur and the now-reactive tailings become a source of the effluent commonly known as acid mine drainage (AMD). Saturated covers have been proposed as an alternative technology to managing AMD, compared to commonly used dry and subaqueous covers. 

The following lab-scale studies focus on the effects of low vs. high water tables within tailings impoundments, in conjunction with a monolayer cover system, in mitigating AMD production. Tailings and cover material were collected from the Faro Mine site in Faro, Yukon. 

Project overview

This study focused on oxygen concentration and unfrozen volumetric water content within freezing conditions through a series of laboratory column experiments.  In order to create a representative model of freezing conditions for the numerical simulations, large instrumented columns were used with an inert material filling, and the evolution of the following parameters were monitored over time and depth:  

  • Volumetric water content;  

  • Unfrozen volumetric water content;  

  • Temperature; and   

  • Oxygen concentration gradient between the water interface and the top of the cover material (only the partially water-saturated portion).  

Project team and funders
Dr. Guillaume Nielsen, NSERC Industrial Research Chair  
Dr. Nicholas Reynier, NRCAN 
Roselyne Gagne Turcotte, Laval University 
Ayesha Ahmad, YukonU Research Assistant  
Yukon Mine Research Consortium (YMRC): BMC, Selwyn Chihong, Newmont Coffee, Casino, Alexco, Victoria Gold Corp., Minto Explorations