In the rolling red hills of northern South Africa, yellow drills painstakingly map one tiny pocket of the metre-thick, saucer-shaped seam of ore that extends over 370km and contains more than three-quarters of the world’s known reserves of platinum.

It could be a million miles from the pulverised trading floors of the world’s financial capitals. But the platinum industry is bearing the brunt of a dramatic reversal in investors’ enthusiasm for metals.