Suitability of an organic residual cover on tailings for bioenergy crop production: A preliminary assessment

Abstract

Hargreaves, J., Lock, A., Beckett, P., Spiers, G. A., Tisch, B, Lanteigne, L., Posadowski, T. and Soenens, M. 2012. Suitability of an organic residual cover on tailings for bioenergy crop production: A preliminary assessment. Can. J. Soil Sci. 92: 203–211. To test the potential for production of bioenergy crops, such as canola and corn, an organic cover was constructed over acid-producing mine tailings containing nickel and copper, belonging to Vale in Sudbury, Ontario, Canada. The 1 m deep cover was of organic residuals (biosolids) obtained from a regional paper mill. Corn and canola crops were successfully grown using agricultural techniques. Crop yields from each of 2 yr from the tailings site were greater than those obtained at an agricultural site in the region. Root, shoot and grain analyses indicated low potential for bioaccumulation of potentially hazardous metals from the organic residual cover or the underlying tailings. Over the short term, there was no evidence of metal movement into the biosolids cover or uptake by the crops from the underlying tailing deposits. Importantly, canola seeds and corn kernels, the feedstocks for biodiesel and ethanol biofuels production, did not accumulate environmentally sensitive metals. This preliminary study demonstrates that the placement of an organic residuals cover on mine tailings to support growth of bioenergy crops is a potential novel reclamation strategy for the mining and smelting industry, or for industrial brownfields in general.

Capping dewatered oil sands fluid fine tailings with salvaged reclamation soils at varying depths to grow woody plants

“…Adding any capping soil regardless of depth reduced foliar concentrations of Al, Cr, and Ti. Hargreaves et al (2012) had similar findings in a study that added a cap of organic residuals over mine tailings containing nickel and copper and showed no evidence of metal movement over the course of the 2 yr study. Evaluating trace metal accumulation in the roots of willows should be further investigated in future studies.…”

“…Renault et al (2000) also found that seedling survival in conifers was reduced to as low as 55% when grown directly in dry MFT. For this reason, adding a capping material plays an important role in reclamation by improving plant growth (Hargreaves et al 2012;Luna Wolter and Naeth 2014;Huang et al 2015), increasing water storage (Zettl et al 2011), and improving soil conditions to support self-sustaining ecosystems.…”

Growth and metal uptake of energy sugarcane (Saccharum spp.) in different metal mine tailings with soil amendments

“…Alternatively, planting energy crops which can adapt to adverse conditions is considered to be a good choice, as it could potentially mitigate the soil contamination and the gradual reduction of fossil fuels at the same time (Olivares et al, 2013). As seen in reports, several researchers have postulated this new strategy of cultivating energy plants, including rapeseed, wheat, corn, castor bean, vetiver grass and willow in metalcontaminated soils for bioenergy production (Hargreaves et al, 2012;Liu et al, 2012;Luu Thai et al, 2011;Van Danh et al, 2007;Witters et al, 2012).…”

Assessing the Long-Term Ecosystem Productivity Benefits and Potential Impacts of Forests Re-Established on a Mine Tailings Site

“…These results certainly suggest that there are environmental risks to this particular tailings revegetation strategy, even though the site is presently a productive forest. An alternative approach that is currently being tested at this site is the use of oxygen consuming organic covers [13,14,20]. This approach, while potentially accelerating the rehabilitation of the tailings, also requires more assessment of its suitability to prevent acid mine drainage particularly if more economical thin covers are used [20].…”

“…Such sites are typically carbon (C) and nutrient depleted, have a massive soil structure, contain high concentrations of metal contaminants and can be acid-generating [8]. An example of such a site, which also has a long and rich history of revegetation trials, can be found on the Vale waste management facility within the city of Greater Sudbury, Ontario, Canada [9][10][11][12][13][14]. In the region surrounding the city of Greater Sudbury, smelting activities in the 20th century created large areas of metal-contaminated, phytotoxic land, which have in many cases been successfully revegetated [15,16], a process that continues to be implemented through a regreening program.…”