Remediation

Mining is a fundamental enterprise to extract metal and mineral resources that support all human activity.

Canada and Mining

Canada is a key producer of critical minerals such as cobalt, graphite, and nickel which are used in advanced battery technologies.(i) Although mining has existed for thousands of years, modern industrial mining has wreaked more havoc on the environment and will continue to so well after a mine’s useful life comes to an end. Unfortunately, many mines are abandoned once they are fully extracted resulting in residual heavy metal leaching into the environment and contaminating soil, groundwater, and surface water. In addition to that, problems with erosion, sinkholes, and the loss of biodiversity arise due to the polluted landscape.

The most prominent issue with mines is the tailings left behind during the mining process. These are slag material left over after separating the valuable fraction of the ore from the non-valuable fraction. During this process, the rock is ground into a fine powder and mixed with water to obtain the ore. The leftover slurry of rock and water then gets dumped to the waterways or collected in bodies of water called tailing ponds or tailing dams. These reservoirs contain high levels of acidic compounds and heavy metals that are toxic to the surrounding environment. Globally, mining operations contaminate between 17 to 25 billion gallons of water a year.

Biocarbon as a Medium for Treatment of Mine Tailings

Biocarbon, made from the pyrolysis of different kinds of organic waste feedstock serves as an excellent treatment to remediate land affected by mining. The structure of biocarbon is porous and has a high cation exchange capacity, which gives it sponge-like properties to adsorb contaminants such as heavy metals. This unique property of biocarbon makes it an efficient medium for treating mine tailings and the consequent remediation of polluted land near abandoned mine sites.

Land Remediation Post Mining

Once the contaminants have been removed from the land, biocarbon can be used to amend the soil for regeneration of the vegetation that once was there. Due to its adsorbent properties, biocarbon demonstrated potential for holding water and nutrients for plant use. Furthermore, biocarbon can be incorporated with green infrastructure to remediate water sources in the affected areas. Systems such as bioswales can expedite water filtration as the residual contaminants can be taken up by the plants in lower quantities for thorough bioremediation in conjunction with biocarbon as biocarbon will boost the support the health and growth of these plants.

[i] Minerals and Metals Facts (canada.ca)