Conuma is dedicated to protecting the environment throughout our mining activities. We focus on sustainable practices and improving how we care for nature by minimizing impacts in active phases of mining and by enhancing reclamation and restorative activities.

Our plans include the accurate measurement and reduction of emissions and educating our employees about their role in protecting the environment.

We also believe in working together with governments, Indigenous Nations, and local communities. We solicit and listen to their ideas and concerns, with concern for ensuring that our work benefits everyone. This way, we are committed to a future where mining and environmental care go hand in hand.

For example, water management is a chief concern of any mining operation. As water flows (rain, snow melt, etc.) over our sites, it contacts the mined areas, including the rock material moved in the mining process. The rock material moved in the mining process contains naturally occurring elements (such as selenium or sulfur), minerals and other materials such as nitrates (blasting residue). As water contacts rock material, selenium (a trace element associated with minerals in the rock) may be released into the water in the form of soluble selenate and selenite ions that can potentially impact aquatic ecosystems and wildlife at elevated concentrations. Conuma employs avoidance and mitigation strategies to minimize effects on the aquatic ecosystem. Avoidance involves testing rock materials on site to understand where elevated natural concentrations of selenium may be present and engineering and designing operations to minimize the chance of selenium dissolving into contact water. Mitigation involves treatment to remove certain elements before the contact water is discharged back to the environment. Conuma has been on the forefront of both avoidance and mitigation strategies.

For example, Conuma operates two Biochemical Reactors (BCR) as part of water management at its Brule site. A BCR is an engineered system facilitating biological reactions that can remove parameters of potential concern from contact water, employing exceptionally low energy intensity. The BCR itself is a lined basin filled with a mixture of hay, wood chips, and limestone (known as the biomixture), and a top layer of hay for insulation. Living within the biomixture are naturally occurring microbial populations (microbes) that remove both nitrate and selenium through reduction-oxidation reactions. The microbes require a food source (substrate) for their growth and metabolic activities. In the context of selenium remediation, the substrate (hay and wood chips) are carbon sources that serve as electron donors for selenium reduction by metabolism (e.g., microbes consume oxygen creating an environment suitable for nitrate and selenium reduction). From there, nitrate is reduced to nitrogen gas and the soluble selenium form (selenate or selenite) is broken down into immobilized forms that are less soluble such as elemental selenium. These less soluble species of selenium are then adsorbed onto the biomixture surfaces or precipitated/settled out within the BCR system.

In addition, Conuma’s alternative Moving Bed Biofilm Reactor (MBBR) water treatment solution being trialed at scale is a biological and physiochemical process that removes selenium and nitrate in an enclosed tank-based system. The MBBR process utilizes carrier media that are kept under anoxic conditions and in suspension using mechanical mixers. In the MBBR, as with the BCRs, biological microorganisms utilize selenate and selenite as electron acceptors and to reduce soluble forms of selenite and selenate to particulate elemental selenium. The particulate selenium can be separated from the treated water by traditional liquid-solid separation methods such as clarification and filtration. The sustainable path forward in water treatment in mining involves continuous improvement of multiple modes of water treatment in the manner Conuma has adopted.