Through its subsidiary, PT Freeport Indonesia (PT-FI), FCX mines one of the world’s largest copper and gold deposits in the Grasberg minerals district in Papua, Indonesia. In addition to copper and gold, PT-FI produces silver. PT-FI operates in the remote highlands of the Sudirman Mountain Range in the province of Papua, Indonesia, which is on the western half of the island of New Guinea. We and our predecessors have been the only operator of exploration and mining activities in Block A since 1967.
PT-FI is currently mining the final phase of the Grasberg open pit, which contains high copper and gold ore grades. PT-FI expects to mine high-grade ore over the next several quarters prior to transitioning to the Grasberg Block Cave underground mine in early 2019. PT-FI has several projects in the Grasberg minerals district related to the development of its large-scale, long-lived, high-grade underground ore bodies. In aggregate, these underground ore bodies are expected to produce large-scale quantities of copper and gold following the transition from the Grasberg open pit. As a result of regulatory uncertainty, PT-FI has slowed investments in its underground development projects in 2017.
Our principal source of power for all our Indonesian operations is a coal-fired power plant that we built in 1998. Diesel generators supply peaking and backup electrical power generating capacity. A combination of naturally occurring mountain streams and water derived from our underground operations provides water for our operations. Our Indonesian operations are in an active seismic zone and experience average annual rainfall of approximately 200 inches.