Africa’s biggest copper smelter, a space-age contraption towering over rickety dwellings and pot-holed roads in Chingola, northern Zambia, whirred into life this month.

The $500m (€395m, £333m) temple to Zambia’s industrialisation hopes might still be a tract of mud, however, had Vedanta, the Indian miner that is the majority owner of the nearby concession, predicted the steep slide in commodities prices.