The most important source of power in PNG is hydro-electric power. The first hydro-electric power was produced by the Bulolo Gold Dredging Company on the Bulolo River in the late 1920s. Almost all power generators were destroyed during World War II. In 1957, the first stage of the Laloki River Scheme (Rouna No.1) began supplying power to Port Moresby. This scheme was extended in the 1960s and 1970s. In the 1980s a major scheme (built by a South Korean company) at Yonki, in the Southern Highlands, was developed to supply highland towns and the coastal town of Madang. A statutory body, the Electricity Commission (ELCOM), has controlled supply since 1963. The ELCOM system is now centered on two gridsone serving Port Moresby and the other Lae and the highlands. The major users of electricity are the commercial sector and the government. About one-eighth of PNG’s electricity comes from diesel or gas turbine generators. In 1992, natural gas from Hides was exploited to supply power to the giant Porgera gold mine. The high cost of power is one of the factors inhibiting exploitation of natural resources and industrial development.