This was granted by the governor of East Nusa Tenggara Province and the company said it was now about to start preparatory work, including site surveying, clearing and civils.
Gulf managing director Hamish Bohannan said that no further approvals were required before construction of the smelting hub could take place.
This would be the first ferromanganese smelting hub development in Indonesia.
Gulf said it had long been recognised that there were many high-grade, 48% manganese outcrops in the islands of Indonesia and specifically in and around Timor including the island of Flores.
Indonesian value adding laws introduced in 2009 prevent the export of minerals unless the mineral had been upgraded in Indonesia.
"While there are small silicon manganese smelters in Indonesia, there is not any significant facility for the production of high-grade ferromanganese alloy," Gulf said.