Production 1914 - 1973: 38.265.000 ton
Number of shafts: originally 1. When in 1966 the mine was joined with ON-IV, shaft of ON IV served as the second shaft. Originally it was already intended as a ventilation shaft for the ON-III.
Location of mine site: Heerlerheide, Heerlen
Construction of the mine started in 1910 in the fields between the Ganzeweide (wordly translated as Goose Meadow) and Rennemig (name after a local farmhouse/estate, demolished for building houses for miners). Already during its construction, the mine was connected to the ON-I, which delivered the required (electrical) power for the construction of the mine. The Oranje Nassau III came into production in 1914. The mine had just one main shaft, situated at the mine area near the Ganzeweide, and an ventilation shaft, situated at a few km's distance at the Heksenberg, at the Brunssumerheide. The ventilationshaft later became a seperate mine, known as ON-IV. The ON-III mine was with respect to production one of the largest of the 4 ON-mines, although the surface facilities were smaller than those of the ON-I. This was mainly due to the fact that at the site of the ON-I a powerplant and several washing plants were situated. The ON-III went with its 825 m level deeper than any other of the ON-mines. In 1966, the mine became merged with the smaller ON-IV.
After the mine was closed (august 3, 1973). and shafts filled, the surface constructions were demolished.The mine site is now a domestic area. At the site of the shaft a primary school and kindergarten was build.The schoolyard is marked with a stone ring and a memorial plaquette were the actual shaft was located.