WATER MANAGEMENT
A question of
BALANCE By Kaj Jansson and Sakari Hiidenheimo
T
oday, the mining industry faces sociopolitical issues due to freshwater usage and the amount of pollution created. Simultaneously, the industry is facing operational challenges caused by water scarcity and quality around the world. To keep up with increasing metal demand and decreasing mineral content in the ore, the site capacities have been growing. In general, the lower the ore grade, the more water-intensive the extraction processes is. Higher metal demand has led to 5%-plus increases in water usage anually in the mining industry. In the future, over 50% of new mining investments will be located in high to extreme water-scarce areas. At the same time, water positive countries need to reduce the amount of 20 | CANADIAN
MINING JOURNAL
effluent generated. In both cases, the closure of process water loops seems to be the only answer to improve sociopolitical issues and secure the water needed for process operation. The sociopolitical stresses have created intense pressure to use water more efficiently in the mining industry. Furthermore, laws and environmental permits that restrict the use of water are tightening. Achieving a social licence to operate is more and more critical for mining companies. A multitude of challenges As the mining industry uses massive amounts of water for minerals processing, water scarcity and management of vast water volumes constitute risks for the companies. The mining industry’s water cycle interconnects with the general hydrologic water cycle. In minerals
and metals processing water is used from seas, rivers, lakes and even groundwater. The level of water consumed is case and process-specific and varies greatly depending on factors such as climate, water quality, geology, ore mineralogy, mine management and practices. Due to this connection, rain, surface runoff, evaporation, infiltration and seepage all have a significant, unpredictable and often seasonal impact on the site’s water volumes and qualities. For example, tailings areas and water ponds are of particular interest as they are a tremendous and changing resource of contaminated water and interact significantly with the environment. Mining operations also drastically change sites’ topographical and hydrological conditions. Mineralogy and water chemistry differ by location and by time. www.canadianminingjournal.com
I m a g e : i S t o c k i m g e s .c o m
Metso Outotec on how miners can achieve more sustainable water use
