Indonesia is the largest nickel producer in the world, with 800,000 tonnes of nickel produced in 2019, up from 606,000 tonnes in 2018. The largest production sites for nickel are in the provinces of South Sulawesi, Southeast Sulawesi, Central Sulawesi and North Maluku. Outside of the mentioned provinces, there are also nickel mines operating in Paser Regency (East Kalimantan), Raja Ampat Regency (West Papua) and in West Seram Regency (Maluku). Further reserves in Papua have also been explored. The most important Indonesian nickel ores are lateritic, primarily located in Sulawesi and Halmahera with mining operations centered at ultramafic rock outcrops. While the lateritic nickel ores are more difficult to smelt compared to nickel sulphide ores, it is more extractable due to its location on the surface. In 2019, it was reported that Indonesia possessed proven reserves of 698 million tonnes of nickel ore, with a potential 2.8 billion tonnes when accounting for unproven reserves. The United States Geological Service reported Indonesia’s nickel reserves to be 21 million tonnes, compared to the global reserve of 89 million tonnes in 2018. Indonesia’s laterite deposits are estimated to comprise 15 percent of the global reserves.