Glencore’s attempt at reinventing mining has run into trouble

FROM THE edge of the Kamoto Copper Company’s pit, it is hard even to see the mechanical diggers toiling dozens of tiers below. The 280-metre hole on the southern edge of the Democratic Republic of Congo is deeper than Africa’s tallest building is tall. Lorries take the best part of an hour to crawl out from its heart. The greenish ore they lug is given its hue by copper but much of its value by cobalt nestled within. Usually driven to South Africa, then often shipped to China, the cobalt will emerge from a series of factories as the priciest component of a battery powering a smartphone or, increasingly, an electric car.