Abandoned metalliferous mines: ecological impacts and potential approaches for reclamation

Abstract

The lack of awareness for timely management of the environment surrounding a metal mine site results in several adverse consequences such as rampant business losses, abandoning the bread-earning mining industry, domestic instability and rise in ghost towns, increased environmental pollution, and indirect long-term impacts on the ecosystem. Although several abandoned mine lands (AMLs) exist globally, information on these derelict mines has not been consolidated in the literature. We present here the state-of-the-art on AMLs in major mining countries with emphasis on their impact towards soil health and biodiversity, remediation methods, and laws governing management of mined sites. While reclamation of metalliferous mines by phytoremediation is still a suitable option, there exist several limitations for its implementation. However, many issues of phytoremediation at the derelict mines can be resolved following phytostabilization, a technology that is effective also at the modern operational mine sites. The use of transgenic plant species in phytoremediation of metals in contaminated sites is also gaining momentum. In any case, monitoring and efficacy testing for bioremediation of mined sites is essential. The approaches for reclamation of metalliferous mines such as environmental awareness, effective planning and assessment of pre-and postmining activities, implementation of regulations, and a safe and good use of phytostabilizers among the native plants for revegetation and ecological restoration are discussed in detail in the present review. We also suggest the use of microbially-enhanced phytoremediation and nanotechnology for efficient reclamation of AMLs, and identify future work warranted in this area of research. Further, we believe that the integration of science of remediation with mining policies and regulations is a reliable option which when executed can virtually balance economic development and environmental destruction for safer future.

Progresses in restoration of post-mining landscape in Africa

“…However, given the long history of mining in Africa (both legal and illegal Artisanal mining), mine wastelands are predicted to cover large areas. For instance, Venkateswarlu et al (2016) reported ca. 6150 officially listed abandoned mines in South Africa alone, with areas contaminated by toxic and radioactive mine residues in Gauteng province, a known source of gold ore, covering 321 km 2 .…”

“…The most notable impact of mining is the change in land form caused by clearing of vegetation, removal of topsoil and disposal of large amounts of waste. Mine wastes usually include waste rock, overburden, slag, and tailings on land surfaces, while mine wastelands are comprised of stripped areas, open-pits, loose soil piles, waste rock and overburden surfaces, subsided lands, tailings dams and other lands degraded by mining facilities (Wong 2003;Li 2006;Sikaundi 2013;Venkateswarlu et al 2016).…”

Sustainable Post-Mining Land Use: Are Closed Metal Mines Abandoned or Re-Used Space?

“…Contamination by heavy metals or radiation in unreclaimed or inadequately reclaimed sites can significantly limit post-mining land use potentials [21,137,138]. Compared to metal mines, quarries (mines which produce building materials and dimensional stone) tend to have more versatile post-mining options, because they usually have less hazardous wastes and are located closer to densely populated areas [28,139,140].…”

“…Further, abandoned or inadequately closed mines may continue to degrade surrounding land, water bodies and air [19][20][21]. Globally, there is a huge number of mines where acceptable mine closure did not take place or was incomplete [5,6,[22][23][24][25].…”

Impact Assessment From Coal Mining Area in Southern Brazil

“…At the end of the mining activity, about 6.500 hectares were abandoned, with no attention being paid to environmental and social changes (Rocha-Nicoleite et al, 2013;Rocha-Nicoleite, 2015;Rocha-Nicoleite, 2017). Similar situations have occurred in other mining areas around the world (Bell et al, 2001;Johnson, 2001;Cravotta, 2008;Mishra et al, 2012;Gutiérrez et al, 2016;Kim et al, 2016;Venkateswarlu et al, 2016;Bailey & Hooey, 2017;Merem et al, 2017).…”