JAKARTA, Feb 15 (Reuters) – * Amman Mineral Nusa Tenggara (AMNT), a copper mining unit of Medco Energi Internasional , has exported 593,806 wet metric tonnes of copper concentrate in year ending Feb. 16, a company official said. * Amman has requested extension of copper concentrate exports from Indonesia, as the permit is due to expire on Friday, AMNT Senior Government Relations Manager Potro Soeprapto told Reuters via text message. * Earlier, a mining ministry official said Amman had not requested an extension.