People who are reading the reports and forecasts of the impacts of climate change know this: we are running out of water. Us here in the Nordics have it a little better than The Middle East, Northern Africa or South Asia, for example, where the water stress (a measure of how much demand there is for an area’s available water supply) is high and harsh (Penney and Muyskens 2023). Many studies – including the ones conducted by Islam and Murakami (2020) and Alvarez-Pugliese et al., (2021) that are referred here – underscore the significance of water as a critical resource in mining operations and highlight the growing competition for fresh water in the industry. Mining is not the only industry that is affected, as water is crucial for all societies, industries, and environments, and it’s our responsibility to save it as much as ever possible and make the necessary changes fast.
Disclaimers
It is a well-known fact that mining consumes a lot of water. Water is consumed in various processes such as extraction, crushing, concentration, leaching and tailings management. This article reviews two studies that have investigated the water consumption of two different mineral production processes using green, blue, and grey water footprints (for explanations, see info box at the end of this article). Both studies emphasize the importance of water management in mining and the need for strategic direction in the sector to improve water management, especially water recycling. EPSE has known this for years, and the goal in our every case is to treat the wastewater so well that it can be reused in the process – achieving thus the closed loop or zero discharge operations. Although only two studies are presented here and can’t be used to generalize consumption to the whole sector and to all operators, water consumption can also be significantly higher than shown in these examples. Mining is a global business and we in the West cannot assume that even if our own environmental limits, sustainability & WF goals are getting more stringent all the time, the same trend will be as rapid in other mining countries of the world. Besides, we all need mining products: you’re probably reading this article on a smart device or computer, you might commute to work by car, bicycle, or public transport, where electrification is happening fast, using the infrastructure provided by your city. You enjoy using electronic appliances in a building that would be impossible to build without the mining industry and so on. There is probably no need to continue the list, you get the point.
Open Pit Copper Mine
In their article ‘Accounting for Water Footprint of an Open-Pit Copper Mine’ Islam and Murakami (2020) provide an analysis of the water footprint (WF) of an open-pit copper mine located in Laos, investigating the green, blue, and grey water footprints of the mining operation. The BWF dominates due to the extensive use of materials in the mining process: the findings indicate that the mine’s GRWF is 52.04, BWF is 988.83, and GWF 69.78 m3/tonne of copper concentrate, respectively, and the mine produced 125,000 tonnes of copper concentrate per year, making the amount of GWF to whopping 8,625 million cubic meters in a year. Installation of a passive effluent treatment system in 2013, however, significantly reduced the mine’s GWF from 69.78 to 13.64 m3/tonne of copper concentrate, demonstrating the effectiveness of water treatment facilities in minimizing the environmental impact of mining operations (although there is room for improvement there). The authors emphasize the need for mining companies to adopt water management strategies that include reducing consumption and reusing water, and suggest that a zero-discharge policy could help mines avoid GWF by reusing or treating water to meet standard quality guidelines before discharge. (Islam & Murakami 2020).
Gold Extraction
Another article, ‘Water footprint in gold extraction: A case-study in Suárez, Cauca, Colombia’ by Alvarez-Pugliese et al., (2021)provides an analysis of the water footprint associated with gold mining activities in Suárez, Colombia, highlighting the substantial environmental impacts of gold extraction on water resources, primarily focusing on the quantification of blue and gray water footprints. The study underlines the need for improved management and mitigation strategies to reduce the adverse environmental effects of gold mining, particularly in areas where water resources are scarce or under significant stress. BWF was estimated at 79.91 m³ per kg of gold extracted, while the GWF ranged between 272,125.39 to 404,825.11 m³ per kg of gold extracted, highlighting a significant environmental pressure exerted by gold mining activities on water resources. The gold refining processes resulted in an annual production of 328.5 kg of gold, which makes the amount of GWF shockingly high: more than 89,4 million, even 156 million cubic meters per year! The substantial GWF is attributed mainly to the use of mercury and cyanide in gold extraction processes, which require vast volumes of fresh water to dilute these pollutants to safe levels. However, the high water consumption is not the only problem: illegal mining is rife in Colombia and in many other areas, and the risks of water pollution are increasing. The authors suggest several strategies to mitigate the negative environmental impacts of gold mining, including the implementation of strategic environmental planning, promotion of mercury-free mining technologies, encouragement of sustainable mining practices, and formulation of policies and regulations to limit gold mining activities in ecologically sensitive areas. The findings serve as a critical input for formulating public policies, control strategies, and environmental regulations aimed at reducing the impacts of gold mining on water resources. The study advocates for the adoption of cleaner production technologies and the enforcement of stricter environmental standards in the mining sector. (Alvarez-Pugliese et al. 2021).
Conclusion
With the emphasis on water as an indispensable resource in mining, it becomes clear that a strategic pivot is required. We must prioritize water conservation and fast-track innovations for water recycling, aiming for a closed-loop or zero discharge operations, as EPSE has been championing. Not only can we save water and make the lives of people better, but we can also make them longer and healthier by removing the dangerous substances – like mercury – from their water sources by limiting the amount of such pollutants in the effluent. Although the examples from just two studies cannot represent the entire mining sector, they are a snapshot of a larger, troubling trend. The urgency is twofold: to implement more sustainable practices within our reach and to push for global adherence to stricter environmental and water footprint (WF) goals. Our reliance on mining is undeniable, yet also a reminder of our responsibility to balance this need with the health of our planet’s ecosystems.
Contact Us
Would you like to discuss how to make your mining operations zero discharge? Let’s talk! In our contact page you can find contact details of our professionals, or contact our CEO jouni.jaaskelainen@epse.fi.
Water footprint (WF) is a multidimensional indicator that estimates the volume of fresh water used to produce a good or extract a resource (in the case of mining) along the productive or extractive chain; it is primarily used in the study of hydrographic basins or specific geographic areas in a defined time scale, contributing to improved decision making in water management and a determination of the appropriate volume of water for humans. (Alvarez-Pugliese et al. 2021).
Green water footprint (GRWF) is – as the name may suggest – the water stored in the soil root zone from rainfall and used by plants. It is particularly relevant for agricultural, horticultural and forestry products.
Blue water footprint (BWF), on the other hand, is water from surface or groundwater resources that either evaporates, is incorporated into a product, is taken from one water body and returned to another or is returned at different times. Irrigated agriculture, industry and domestic water use can each have a blue water footprint.
Grey water footprint (GWF) is the amount of freshwater needed to incorporate pollutants to achieve certain water quality standards. The grey water footprint takes into account point source pollution that enters the freshwater resource directly through a pipe or indirectly through runoff or leaching from soil, impervious surfaces or other diffuse sources. (Water Footprint Network, n.d.).
References:
Alvarez-Pugliese, C.E., Machuca-Martínez, F., Pérez-Rincón, M., 2021. Water footprint in gold extraction: A case-study in Suárez, Cauca, Colombia. Heliyon 7, e07949. https://doi.org/10.1016/j.heliyon.2021.e07949
Islam, K., Murakami, S., 2020. Accounting for Water Footprint of an Open-Pit Copper Mine. Sustainability 12, 9660. https://doi.org/10.3390/su12229660
Penney, V. and Muyskens, J. (2023). Here’s where water is running out in the world — and why. The Washington Post. Washington, D.C. Referred 21.3.2024, available online: https://www.washingtonpost.com/climate-environment/interactive/2023/water-scarcity-map-solutions/
Water Footprint Network. (n.d.) Referred 21.3.2024, available online: https://www.waterfootprint.org/water-footprint-2/what-is-a-water-footprint/#fact-and-figures
This article was written by Anni Honkonen.