The structured loan facility is with Glacier International Depository, Legal and General Investment Management and HSBC Bank.
The company is now fully funded to complete the construction and commissioning of the first two smelting furnaces at Kupang.
Construction of the facility is currently 60% complete, with about US$13 million left to spend over the next 6-7 months.
Gulf managing director Hamish Bohannan said the company now had a clear line of sight on the pouring of first metal in the September quarter.
"With $13 million required to complete the construction and commissioning of our first two smelters, we now have ample capacity to fast-track high-impact mining and exploration programs targeting Indonesia's abundance of high-grade manganese ore deposits," he said.
Gulf shares had been halted since December 16, but resumed trading today and jumped 40% to A0.7c.