The opening ceremony was attended by Ecuador's vice president Otto Sonnenholzner and energy minister Carlos Perez.
The company had earlier received the Industrial Water Permit and Administrative Act from La Secretaría Nacional del Agua (SENAGUA), allowing the project to move into production.
The process plant has been in the hot commissioning phase for the past month.
Fruta del Norte is expected to produce 310,000 ounces a year of gold for 15 years from a resource of more than 5Moz.