A momentary discharge caused by human error from the mining site towards Pirttipuro

Due to a fault situation resulting from human error, unpurified water has been discharged outside the mining site for a maximum duration of 24 hours (28 July – 29 July 2017). Normally, the waters are directed to a settling pond and from there to the process or to be purified.

The fault situation occurred in a waste rock area where acidic water containing metals was erroneously directed to a catching ditch instead of the open pit, and through the ditch to the Pirttipuro route. The water discharge to Pirttipuro crekk and Talvijoki river was detected quickly and was immediately stopped.

According to measurements, the nickel concentration of the water led from the mining site was 14.1 mg/l at its highest in Pirttipuro on Monday, 31 July. On Thursday 3 August, the concentration had decreased to 1.7 mg/l at the same measurement point. The nickel concentrations measured downstream of Talvijoki have been significantly lower. The nickel load resulting from the discharge is estimated to be at most 100 kg in total. The company continues to take samples from Pirttipuro and Talvijoki at a heightened frequency.

Terrafame estimates that the impacts of the discharge on the area will be small and that despite this the emission quotas for different metals will not be exceeded during the year. The company has notified the supervisory authority and nearby municipalities of the discharge, and has also ensured that a similar error cannot be repeated. 

Additional information on 14/8/2017: According to Terrafame's report, the fault situation lasted 21 hours, and according to a revised estimate, the maximum amount of the nickel discharge has been 108 kilograms.

More information on measurement results from Pirttipuro and Talvijoki

Terrafame Ltd. is a Finnish multi-metal company producing nickel, zinc and cobalt at its mine and metals production plant located in Sotkamo. Our aim is to conduct environmentally sustainable, safe and profitable operations.