The failure of a diesel fuel storage tank at a combined heat and power plant (CHPP) owned by Russian mining giant Nornickel may have been due to melting permafrost, the company’s First Vice President Sergei Dyachenko has told journalists.
The tank, at CHPP-3 in the Kayerkan area in the city of Norilsk in northern Russia, collapsed on 29 May following the sudden sinking of its supports, spilling an estimated 20,000 t of diesel into the surrounding area and the nearby Ambarka River. A car passing by the site at the time of the collapse sparked a fire as it was caught in the fuel spill. The driver escaped uninjured but the fire spread to an area of 300m2 before emergency teams managed to put it out.
Nornickel says that that emergency teams from its Polar Division and the subsidiary which runs the plant, Norilsk-Taymyr Energy Company (NTEC) arrived immediately and by the following day had collected 100t of spilt diesel for recycling and removed contaminated soil to a waterproof, leakproof facility temporarily before treatment. The ground was treated with sorbents before fresh soil was added. NTEC and the Russian environment agency Rosprirodnadzor have conducted join aerial inspections of nearby water bodies and have placed containment booms on the Ambarka River to stop the spread of diesel contamination. Norilsk city authorities have declared a state of emergency.
Russia’s state-owned newswire TASS reports that Dyachenko said on 2 June: ‘The company still has to sort many things out. This will be a thorough work to inspect and assess the condition of the tank that caused subsidence of the base the tank had rested upon. We can now assume according to documents we are retrieving that permafrost thawing could occur due to abnormally mild summer temperatures lasting for several years and that the partial subsidence of base supports could take place.’
It is thought that the subsidence of the base supports caused the base to collapse, resulting in the fuel spill. Prior to the spill, the tank had operated safely for 30 years.
Nornickel says it has contained the spill in the river, and NTEC teams are now inspecting other diesel fuel storage facilities to assess the risks, particularly paying attention to potentially hazardous facilities installed in permafrost.