Kazakh mining groups Eurasian Natural Resources Corporation and Kazakhmys have held informal discussions about combining to form a company worth roughly £20bn ($40m), with leading positions in copper, iron ore, ferrochrome and aluminium.

ENRC disclosed on Wednesday that it had held an “informal dialogue” with Kazakhmys after rumours of a deal pushed up Kazakhmys’s share price. The shares soared even higher after the news, closing up 16 per cent at £17.80, indicating the market thinks ENRC will pay a premium to take over its compatriot.