Russian mining company Nornickel’s operating director Sergei Dyachenko has told reporters that the diesel tank which collapsed on 29 May 2020, spilling more than 20,000 tonnes of fuel into the surrounding land and waterways, had been incorrectly constructed.
The collapse of the tank, which was storing 21,163 tonnes of diesel as a back-up fuel for a combined heat and power plant owned by Nornickel subsidiary Norilsk-Taymyr Energy Company (NTEC) near Norilsk in northern Russia, was originally blamed on melting permafrost. While this was a contributing factor, Dyachenko said that whilst dismantling the collapsed tank, engineers found that the piles under the tank, which should have been driven 800 mm into the bedrock, in fact stopped around 1 m above it, according to Russian news agency Tass. The piles were sitting in a mixture of sand and clay.
Dyachenko said that when the tank was built in 1981, the soil was frozen solid so the piles were not deepened as they should have been.
‘The extremely warm summers over the past years and mild winters have made themselves felt, most likely. And the fact that colleagues once left these piles unburied played a cruel joke on us,’ he said, adding that investigations are ongoing.
The tank underwent repairs in 2018, but state inspections passed it as safe afterwards.
Meanwhile, the Yenisei Interregional Department of the Federal Service for Supervision of Natural Resources (known as Rosprirodnadzor), is taking NTEC to court, to claim compensation of RUB 147.8 billion (€1.7 billion) for the spill. Nornickel says that the court action is ‘premature’ and that the agency should have waited until the final expert assessment of the damage is complete.
‘Our joint work should result in a comprehensive rehabilitation plan. We still believe that only after completion of the assessment and the expert review will we able to determine accurately the amount of fuel that was released into the water and soil, and thereby determine accurately the amount of environmental damage,’ says the company.
Nornickel has now finished pumping contaminated water from the rivers into a tailings dam for storage until the fuel can be separated. Work to clean the riverbanks and surrounding areas is ongoing.