Zambian President Michael Sata (Reuters picture) Vedanta Resources Plc (VED)’s Zambian unit apologized to the president of Africa’s biggest copper producer after the country revoked the work permit of its chief executive officer.Konkola Copper Mines Plc, the southern African nation’s biggest investor, “wishes to unreservedly apologize to the president of the republic of Zambia and the nation for the unfortunate remarks”