Green Mining Initiative to Reduce Mining's Environmental Footprint

By Marisa Brennan
May 2010

A stream at Howards Pass along the Yukon-NWT border provides an ideal field laboratory for studying aqueous metal transport and attenuation in the natural environment.

It’s hard to believe that what was once a mine tailings site (the “sand” left after ores are crushed and processed) in Copper Cliff, Ontario, is now a field of thriving corn and canola crops.

This is an example of mine rehabilitation — just one of the many “green” mining initiatives that are being developed by Natural Resources Canada (NRCan). With its partners, NRCan is working to ensure that mining, one of Canada’s most important resource sectors, is sustainable as well as profitable.

Last year, NRCan launched the Green Mining Initiative (GMI), a program that promotes sustainability through mining and takes advantage of new market opportunities. “It’s about finding innovative ways to minimize the waste produced by mining, transform it into environmentally friendly resources for other uses and leave behind only clean water, rehabilitated landscapes and healthy ecosystems,” says Louise Laverdure, the Director of Green Mining Research at NRCan.

The program focuses on four key areas of green mining research and development: footprint reduction, waste management, mine closure and rehabilitation, and ecosystem risk management.

Footprint Reduction

A NRCan summer student is shown collecting cattails and bulrush on tailings in Copper Cliff, Ontario for transplantation into another wetland area. This work was undertaken in relation to CANMET-MMSL's Green Mines Green Energy initiative.

To minimize the creation of environmentally hazardous and costly mining waste, NRCan’s CANMET Mining and Minerals Sciences Laboratories (CANMET-MMSL) are now looking for greener ways to selectively extract valuable minerals from the rock.

CANMET-MMSL’s experimental mining facility in Val d’Or, Quebec, is exploring less volatile alternatives to explosives, which cause unnecessary rock breakage. One such method involves using electricity to heat the vein containing valuable minerals.

“When you heat the vein, it creates micro-stress, making small cracks in the rock, and the ore breaks off in small flakes,” explains Louise. “This is a promising method for reducing the amount of material that needs to be hauled to the surface.”

To learn about research at the Val d’Or mining laboratory, visit the Natural Elements article.

Innovation in Waste Management

Since it is not possible to completely eliminate mine waste, the projects focused on waste management will help to better manage and dispose of waste. This involves preventing and treating acid-related damage, minimizing and reprocessing waste and developing alternative waste disposal technologies.

NRCan is also advancing zero-discharge processes by “re-mining” existing waste materials to recover valuable metals and minerals. “In one project, we’ve developed a process to recover approximately 80 percent of the zinc from water treatment sludge, which is the precipitated 'mud' where contaminants settle,” says Louise.

Mine Closure and Rehabilitation

When mining projects are completed, it is important to ensure that they do not leave an ecological footprint. Through the GMI, NRCan will look at technologies for mine rehabilitation, habitat restoration and ecological reclamation and climate change adaptation by the mining industry, building on the ongoing efforts of the National Orphaned and Abandoned Mines Initiative.

Ecosystem Risk Management

To understand the ecological impact of mine waste, NRCan is examining metal toxicology, metals in soils and the biological impacts of submerged tailings. This is important because, as Louise says, “We currently have a good understanding of the actual chemistry of waste, but less is known about the impacts of waste on ecology, flora and fauna.”

Through Green Mines - Green Energy, an initiative launched in 2007, NRCan examined the question of how to handle mine tailings — which become acidic when exposed to oxygen and water — and prevent vegetation from growing. Researchers found that applying organic waste from communities and pulp and paper mills to former tailings sites provided a viable soil on which biofuel crops like canola, corn and soy could be grown.

To read about related articles, see Mining Technology