Mining is crucial to the development of society. Even as countries grow from developing to developed economies, and their needs change, they still require natural resources to produce infrastructure and energy. This permanent demand means that there will always be a need for the mining of natural resources. However, mining can come at a high cost to the natural environment; it is the largest producer of global waste and produces billions of tons annually (Carmo et al. 2020).
Image Credit: metamorworks/Shutterstock.com
The waste from mines can be sorted into solids and fluids, with the solids being piled up as slag/spoil heaps and the fluids being contained in tailings pools. These high volumes of waste, if not treated properly, can be enormously damaging to their surrounding environment due to the leaching of heavy metals and toxic compounds (Carmo et al. 2020).
Disasters can also occur when there are engineering failures that cause tailing ponds to burst or spoil heaps to collapse, causing tailings spillages (Mount Polley Mine disaster, 2014) and landslides (Aberfan disaster, 1996) that can cause untold damage to local populations. Over the last 34 years in Brazil, there has been one mining dam failure every three years (Carmo et al. 2020).
The global population is increasing by 1.036% per year (The World Bank, 2020), meaning that the demand for mining products is increasing. This problem is exacerbated by the fact that metal ores are a finite resource and are degrading with time. These issues clearly show that a solution is needed that will address both the increased demand for minerals and the issue of waste management. Sustainable mining is an umbrella term for a group of practices that aim to achieve this.
Internet of Things in Mining
Mining inevitably causes changes and damage to the natural environment, but it is accidents that cause disasters and widespread contamination. The Internet of Things (IoT) is a concept that could help to reduce the instance rate of disasters through increasing the communication between the equipment in a mine (Salam, 2020).
This wireless communication technology could improve real-time monitoring capabilities by including data on the geology and mineralogy of the area that surrounds sensors (Salam, 2020).
Real-time data from these sensors throughout the mining and waste storage areas could be transmitted to interrogators and incorporated into flexible hazard maps, helping to improve early warning systems. This technology could also mitigate large-scale disasters by identifying areas that are at risk of failure.
Current monitoring systems are incapable of analyzing these high levels of data, which is why IoT is a useful concept in mining.
Biometallurgey and the Reduction of Mining Waste
Biometallurgey is an important technology that has the potential to reduce waste from mining and its associated risks. This is a general term for processes that use microorganisms to extract metals from low-grade ores and minerals.
Compared to conventional hydrometallurgical techniques, which can cause high levels of environmental damage through the leaching of acidic and toxic waste, biometallurgey does not release any harmful chemicals into the environment and is a more sustainable approach (Sajjad et al. 2019).
Bioleaching is a process in which iron/sulfur-oxidizing bacteria are mixed with crushed metal ores. The microbes break down the ores and convert the insoluble metal compounds into soluble products in a bid to reduce the toxicity of their environment (Chung et al. 2019).
These products are then removed and later separated to retrieve the valuable metals.
Past studies have shown that bioleaching can produce metal yields of more than 90% in both aerobic and anaerobic conditions. Copper slag heaps have been used to produce a copper extraction of 91%, and 98.5% of extractions of zinc have been produced from leached compounds that enter the environment (Sajjad et al. 2019).
Using biometallurgey on areas with leached metal compounds is useful for recycling tailings to produce metal and to help reduce the toxicity of the environments surrounding mines, playing an important role in land remediation. The successful use of bioleaching for concentrating low-grade ores, re-using waste products, and reducing the metal toxicity of contaminated land means that it will become center-stage in the future as demand further increases and ore bodies degrade.
The Future of Sustainable Mining
This report has outlined some technologies that will become crucial in the future, as the need for more sustainable mining practices increases. The Internet of Things will be used to improve communication between devices and allow for real-time observation of mining sites and their waste material; this will create better early warning systems for disasters and increase the efficiency of ore identification and extraction.
Biometallurgey is a vital technology that allows for the recycling and treatment of mining waste and can even help with land remediation.
However, one of the most powerful methods for solving this problem can be practiced now, which is increasing communication and working with local populations.
Socio-environmental conflicts (those concerning natural resource acquisition) are the second most common in the world (Carmo et al. 2020). This means that the existence of mines and mineral resources causes conflicts between these communities, along with the direct harm to local populations caused by poor waste management.
This array of problems means that companies must work with local populations to reduce the negative impact of mines. Community Sustainable Development Plans (CSDP) are produced based on the input of local authorities and help mining companies work towards sustainability goals that will benefit the community (MMSD, 2002).
For change to happen at a social level, companies must hold themselves accountable. Communication is an important step that is needed to earn the trust of local populations, which is necessary to mitigate disaster.
References and Further Reading
Carmo, F.F., Lanchotti, A.O. and Kamino, L.H. (2020) Mining Waste Challenges: Environmental Risks of Gigatons of Mud, Dust and Sediment in Megadiverse Regions in Brazil. Sustainability, 12(20), p.8466. https://doi.org/10.3390/su12208466
Salam, A. (2020) Internet of things for sustainable mining. In Internet of Things for Sustainable Community Development (pp. 243-271). Springer, Cham. https://doi.org/10.1007/978-3-030-35291-2_8
Sajjad, W., Zheng, G., Din, G., Ma, X., Rafiq, M. and Xu, W. (2019) Metals extraction from sulfide ores with microorganisms: The bioleaching technology and recent developments. Transactions of the Indian Institute of Metals, 72(3), pp.559-579. https://doi.org/10.1007/s12666-018-1516-4
Chung, A.P., Coimbra, C., Farias, P., Francisco, R., Branco, R., Simão, F.V., Gomes, E., Pereira, A., Vila, M.C., Fiúza, A. and Mortensen, M.S. (2019) Tailings microbial community profile and prediction of its functionality in basins of tungsten mine. Scientific reports, 9(1), pp.1-13. https://doi.org/10.1038/s41598-019-55706-6
Mining, M., SUSTAINABLE DEVELOPMENT PROJECT (MMSD) (2002) Breaking New Ground. London: Earthscan. https://pubs.iied.org/9084iied
The World Bank (2020) Population growth (annual %). [Online] Available at: https://data.worldbank.org/indicator/SP.POP.GROW (Accessed 31 October 2021).