Case Study: Copper, Nickel and Selenium Remediation

Challenge

A decommissioned open pit copper mine filled with water. The water in the pit requires treatment and discharge annually to treat the contaminants of concern (mainly copper), that enter the pit through runoff from the surrounding waste rock. The pit acts like a sump within the watershed, pulling the surrounding groundwater and surface water to collect in the pit.

Copper is the main parameter of concern for the operator, with the area having a naturally high level of copper contaminating the surface and groundwater.

The background copper concentrations in the surface water surrounding the site are naturally high due to the high copper content in the bedrock. Therefore, the allowable discharge limits provided by the ministry are quite low relative to other sites because the receiving waters do not have the capacity to handle more “loading” of copper. Other parameters of concern include Nickel and Iron, although in much lower concentrations.

Current challenges of the existing treatment systems such as liming to chemically precipitate copper and other metals as well as prospective biological treatment systems, have raised the operator’s need for a more cost-effective, technically viable system that can sustainably remove copper and other metals from the subject water for the long-term.

Key Project Requirements

• Meeting strict copper, nickel and selenium removal guidelines to discharge into receiving surface water bodies;

• Small footprint of treatment system and minimal reliance on electromechanical requirements;

• Short retention times and reasonable longevity;

• Cost-effectiveness of the treatment system;

• Long-term sustainability.