US-based mining startup KoBold Metals, backed by billionaires Bill Gates, Jeff Bezos and Richard Branson, will invest $150 million in Mingomba copper-cobalt mine in Zambia. With this deal, KoBold Metals will hold majority stake in the project, a joint venture with Australian firm EMR Capital and Zambia's ZCCM Investments Holdings. Zambia is Africa’s second-largest producer of copper.