Contaminated water management at Europe's largest nickel mine

Overview:

Europe's largest nickel mine located in northeast Finland, faced significant challenges in managing water contaminated by sulphates and heavy metals. The issues stemmed from excessive rainfall leading to water storage, contamination of rainwater by mining activities, and leakage from a tailings pond containing gypsum sediment. These challenges jeopardized the mine's operations and required an effective solution to ensure environmental compliance and financial feasibility.

Challenge:

In 2012, the mine encountered several water-related challenges. Excessive rainfall forced the mine to store millions of cubic meters (tens of millions of cubic feet) of water on-site, leading to contamination from mining activities. Additionally, high levels of contaminated water accumulated in the deepest part of the open-cast mine, forcing a temporary halt in ore mining operations. In November, a tailings pond leak released approximately 220,000 m³ (7.8 million ft³) of effluent containing metals and sulphate compounds. These challenges, combined with the vast 61 km² (23.5 mi²) mine area, necessitated a cost-effective and efficient water management solution.

Solution:

To address the water contamination issues, a comprehensive solution was implemented in 2013. The solution involved the use of 13.7 m (45 ft) wide and 50.7 m (166 ft) long GEOTUBE^® containers installed on a 1.5 mm (60 mil) smooth GSE^® HDgeomembrane to capture heavy metals from the contaminated water. The project benefited from the collaboration of various experts, including site management, a dedicated team of Solmax dewatering professionals, specialized engineering partners and a contractor with expertise in using Watermaster environmental dredges in conjunction with GEOTUBE technology.

The cleanup operation commenced in March 2013, exceeding expectations from the outset. The treatment of sludge and mining effluent using GEOTUBE technology significantly reduced heavy metal concentrations, well below local environmental authority limits. Consequently, ore mining and crushing operations resumed in May 2013, ensuring the normal functioning of all four production areas within the mine. The mined ore also played a vital role in maintaining the site's water balance by binding millions of tonnes of water in the leaching area. This successful solution demonstrates the effectiveness of GEOTUBE technology in addressing large and complex mine wastewater management challenges.