“We are asking for 10 per cent across the board,” says Lesiba Seshoka, a trade union officer at Impala Platinum, the world’s second-largest platinum miner.

Mr Seshoka’s demand that the South African miner pay higher wages for its workers or face a strike is not exceptional in today’s mining industry. On the contrary: as prices of base and precious metals rise, workers from Canada to Chile are demanding higher pay. Otherwise, they say, they will strike.