Kazakh copper miner Kazakhmys has rejected a £7bn takeover indicative offer from rival and compatriot Eurasian Natural Resources Corporation, saying the offer was “derisory and ill-considered”.

ENRC, which produces ferrochrome, iron ore and aluminium, first said it was interested in bidding for Kazakhmys in March. Kazakhmys said that ENRC had contacted it on Thursday night offering £10.22 in cash and 0.413 ENRC shares for each Kazakhmys share.