Het mijnwezen in Nederlands-Oost-Indië 1850-1950

The Mining Department (Het Mijnwezen) in the Netherlands-East-Indies was set up in 1850. Its task was to assist the operations in the Tin Mines in Bangka and to find other mineable deposits of useful minerals. The primary purpose was to earn quickly lots of money for the Netherlands, which were very much impoverished and in heavy debts after the Napoleontic occupation.
Starting with four mining engineers, all from the Dutch Technical School, this number would grow, to a maximum of 70 engineers and 10 geologists in 1929. The Pacific War (1942-1945) made an end to the Dutch colonial presence.
Initially all mining activities were reserved by the Mijnwezen. But gradually private investors were admitted. Mijnwezen had a supervisory role and was involved in selecting the winners of the various acquisition rounds. The oil finding and producing was the near-monopoly of the Royal Dutch Shell, a 60/40 joint company with Dutch and English roots, operating under the name Bataafse Petroleum Maatschappij (BPM).
The production of a geological map of the entire colony progressed slowly owing to the dense afforestation and the heavy monsoon rainfall. There were only few Dutch geologists available and there was reluctance to hire foreigners. A bright exception was R. Verbeek, who was both engineer and geologist and had studied in Germany. His work was outstanding, but even so, the geological map of Indonesia was far from complete when the Pacific War started.
The search for mineral deposits was largely unsuccesful, basically because Indie was not blessed that way. The noteworthy exceptions were the discovery, in 1862, of a a large coal deposit, called Ombilin, in the mountains of Western Sumatra and, on the island Billiton, a large tin occurrence was found to be exploited by private investors. Oil exploration, all by private firms, resulted in a large number of relative small oil producing fields on Sumatra and Java.
By far the most significant geology-and-mining contribution of the colonial period, which ended in December 1950, were the exceptionally large oil fields in Sumatra, all found before the Pacific War by American companies (especially Caltex). These were exploited much to the advantage of the newly born Republic Indonesia.
All together, the story of Het Mijnwezen is not one of succes, but rather one of perseverence. Its greatest financial contribution to the Netherlands had been the revenues from the Bangka Tin Mines, which were an inheritance from pre-colonial efforts.
The most complete summary of the Mijnwezen and its geological and mining efforts and result is summarised by R.W. Van Bemmelen (1949) in 732 pages and 267 pages in Vol. II pages Economic Geology.