JAKARTA, Indonesia—Indonesia has cut a deal with Freeport McMoRan Inc. on export taxes and royalties, allowing the U.S. mining giant to resume copper-concentrate exports after a six-month stalemate.

The Phoenix-based company, one of the world's biggest copper producers, mines almost a fifth of its copper in Indonesia and controls Grasberg, the country's largest mine. Indonesia is a major producer of copper, tin and bauxite, and ranks as the world's fourth largest exporter of copper, an essential modern metal used to make pipes...