Willem-Sophia (1902 -1970)
Production 22.678.000 ton.
Location of mine site: Spekholzerheide, Kerkrade
Number of shafts : 5

The concessions Willem and Sophia were granted in 1860 and 1861 by the government of Prime Minister Thorbecke to the Nederlandse Bergwerkvereniging in the Hague. The Bergwerkvereniging went bankrupt in 1881 as they could not succeed in constructing a shaft in the difficult and very wet top soil of the concession fields. In the year 1898 the concessions were sold to a Belgian company called: Société Anonymes des Charbonnages Néérlandais Willem et Sophia. Using the freezing method (invented by Poetsch) for delving shafts in the wet Limburg top soil, this company, following the enormous success of the Honigmann brothers, quickly succeeded in constructing 2 shafts in the village Spekholzerheide near Kerkrade. In 1902 the Mine, named Willem-Sophia went into production.In 1950, the German Melanie concession was added. The mine produced coal for domestic use, and belonged to the smaller Dutch coal mines. The mine had 5 shafts, of which some (Ham-I, Ham-II) were just ventilation shafts. The mine was closed in 1970.

The rock waste dump of the Willem-Sophia mine for many years burned internally. In former years, slags from the furnaces of the mine were dumped on top of the rock waste dump, which as a result catched fire. Later, when the mine was closed, the rock waste dump was removed, and the sintered material from inside (colored red) was milled, sieved, and sold, for use in road construction etc.. Black material, still containing coal, was washed, and the recyled coal was used in powerplants.