Even by Russian standards, this tussle has it all. Feuding oligarchs; national politics; and a fight to control what would be one of the mining industry's biggest companies, conducted within a head-spinning commodity bubble.

Very simply, UC Rusal, the world's number one aluminium producer, is stalking compatriot Norilsk Nickel, similarly positioned in nickel and palladium. Norilsk was the plaything of two Russian oligarchs, each owning about a quarter of the company. But a cooling between the pair has seen Mikhail Prokhorov's shares head to Rusal. That has not just flustered his old business partner, Vladimir Potanin: Norilsk's minority investors worry that the next step is Rusal pushing for a merger on the cheap.