Since 1996, we have reused the biosolids that result from Metro Vancouver’s waste water treatment process to improve reclamation at Highland Valley Copper (HVC). Biosolids are a source of nutrients and organic matter that can be used to support the establishment of vegetation. Using biosolids helps improve the soil’s structure, nutrient availability and water capacity so we get more sustainable vegetation.
We have a permit from the Province of British Columbia to apply the biosolids to the areas on-site that we want to reclaim,” said Jaimie Dickson, Senior Environmental Coordinator at HVC. “Before this occurs, an agrologist conducts soil testing to make sure that when the biosolids are applied, metal levels will not exceed regulations.”
The first few years we used biosolids, demonstration plots were established on tailings and waste rock to evaluate the effectiveness of various application rates and methods. The biosolid-treated plots often exceeded the results of conventional reclamation methods. Extensive monitoring for vegetation, soil chemistry and water quality indicated no detrimental impact on the environment. Throughout the past 17 years, more than 380,000 wet tonnes of biosolids have been applied to more than 700 hectares of disturbed land.
At HVC, most reclamation is done directly on tailings and overburden, which is made up of low organic matter and limited nutrients. Using biosolids assists in the reclamation process and creates a new use for waste that would otherwise go to landfills. Using biosolids also aligns with our approach to materials stewardship. We work to incorporate product stewardship practices, including recycling, wherever possible at our operations. By using biosolids to make our reclamation methods more effective, we thereby improve the sustainability of our mining life cycle at HVC.
“We are pleased to share our past experiences and best practices in biosolid-assisted reclamation with others,” said Dickson. “We can also provide data and reports that demonstrate that biosolids are safe to use and can improve reclamation performance.”
In the coming years, we will continue to use biosolids to support our reclamation activities and we will expand our research on combining biosolids with wood chips to better grow trees and shrubs on reclaimed sites. As our energy business unit grows, we are also participating in research trials to demonstrate the appropriateness of using biosolids for reclamation in the oil sands industry.
This case study was originally published in our 2012 Sustainability Report.