Most of the oil came from from Sumatra. The DEI oil was most abundant and among the sweetest crude oil produced anywhere in the world. The Dutch Indonesian oil fields were some of oldest in the world. Commercial fields were discovered in northern Sumatra (1883). The Koninklijke Nederlandsche Maatschappij tot Exploitatie van Petroleum-bronnen in NederlandschIndië (Royal Dutch Company for Exploration of Petroleum sources in the Netherlands Indies) ws founded (1890). The Shell Transport and Trading Company was a British company that had began drilling in Kalimantan (1891). The two companies merged to form Royal Dutch Shell (1907). Royal Dutch Shell became a major international oil giant. Initially they dominated oil exploration in the British and Dutch Malay-Indonesian colonies for three decades. Royal Dutch Shell was soon operating concessions in Sumatra, Java, and Kalimantan (Borneo). Royal Dutch's output from the DEI came to represent about 4 percent of total world production. What was to become Indonesia's most important oil fields (Duri and Minas) in central Sumatr, were discovered just prior to World War II by Caltex (a joint venture between the American companies Chevron and Texaco). Production did not, however, figure in World war II. By the time of World War II, the annual output of 65 million barrels annually was more than enough to make Japan self-sufficent and fuel not only Japanese industry, but all of the increased demands that would be rquired for a naval war in the Pacfic. The DEI did not produce crude oil. The Dutch at a cost od 150 million gilders built a huge refinery at Balik Papan in eastern Borneo (1920s). Oil was, however, not the only resource. The DEI ranked only behind British Malaya in tin production. Production totaled 44,563 tons (1940). The Dutch also mined bauxite and coal in the DEI. ubber, copra, nickel, timber, quinine, and important foodstuffs such as sugar, rice, tea, and coffee.