Steenkoolmijn van Winterslag Genk · Limburg · Belgium

Winterslag was established on heathland in the commune of Genk following the confirmation of coal in Belgian Limburg by André Dumont in 1901. Initial survey borings in 1901 and 1902 by the Société Limbourgeoise de Recherches et d'Exploitation at Gelieren and Winterslag, and by the Société La Campine at Zutendaal, were followed by more systematic Foraky probing in 1908 and 1909, including borehole Genk 69 (= Winterslag) to a depth of 1,050 metres. These established the character of the overburden and the position of the coal platform.

The concession Genck-Sutendael of 3,963 hectares, covering the communes of Genk, As, Mechelen-aan-de-Maas, Opgrimbie, and Zutendaal, was granted by royal decree on 3 November 1906. It was assigned to two associated groups: on one side the Charbonnages de Ressaix together with the Société Limbourgeoise de Recherches et d'Exploitations, and on the other the Charbonnages de Ressaix together with the Société Minière de Pitteurs-Hiegaerts. These groups entrusted the exploitation to the Charbonnages de Ressaix, which in turn brought its concession rights into a consortium named S.A. des Charbonnages de Ressaix, Leval, Péronnes, Ste-Aldegonde et Genck. A royal decree of 23 November 1912 separated a sub-concession named Winterslag of 960 hectares from the original Genk-Zutendaal concession; the remainder stayed with the Ressaix group. For the exploitation of Winterslag, the Charbonnages de Ressaix consortium associated itself with the Parisian commandite firm of Schneider et Compagnie. The S.A. Charbonnages de Winterslag was founded on 30 November 1912, with the Walloon mines contributing the land, installations, and a number of workers' houses, and Schneider providing capital. Schneider, through its Creusot metallurgical operations, was a large consumer of the fat coal that Winterslag would produce. The key shareholders were the Charbonnages de Ressaix group associated with Evence Coppée, and the Schneider group.

In Winterslag the engineers did not encounter the treacherous quicksand layers that caused flooding and delay at other Kempen collieries. Freezing borings for Schacht I started on 19 March 1910, executed by the Maatschappij Foraky and the S.A. Entreprise Générale de Fonçage de Puits from Paris. Whereas the freezing method had previously only been applied to depths of around 200 metres for shafts of four metres diameter, at Winterslag it was applied to 430 metres. Both shafts have a useful diameter of six metres, lined largely with original cast-iron tubbing. On 28 July 1914, just before the outbreak of the First World War, the first piece of coal was raised from Schacht I. Under the German occupation the development of the mine was able to continue with relative continuity, and in 1917 Winterslag became the first of the Kempen mines to enter commercial production, making it the oldest producing colliery in Belgian Limburg.

Schacht II's headframe, standing 45 metres tall, was designed and built by the Société de la Meuse of Liège in 1915, and is the oldest headframe in the Kempen coalfield. The reception building for Schacht II was constructed from 1916 to 1917. Schacht I's headframe was later renewed for a fully automatic Koeppe skip system. The two winding houses each accommodate two separate machine rooms; the winding machines of Schacht I are the oldest extraction machines in all the Kempen mines. An electric power station was developed from 1919, with its original switchboards and control panels surviving in situ. Working levels were initially installed at 600 and 650 metres, and from 1949, in the framework of the post-war modernisation plan, a new working level was developed at 850 metres. The Eerste Cité, the first workers' housing estate, was laid out from 1912 to a garden suburb design by Adrien Blomme, intended for engineers, senior staff, office workers, and skilled labourers, with boarding houses for single men and communal facilities including a church and schools. A second cité followed between 1922 and 1928 for Eastern European workers, and further housing was built into the 1930s and through the post-war Kolenslag period.

In the first years of production, Winterslag had a poor safety record with many fatal accidents. Peak employment of 6,250 miners was reached in 1953. Peak annual production of 1,635,514 tonnes was achieved in 1967, and total production over the mine's life amounted to approximately 66,593,000 tonnes. In 1929 the concession on the unapened Genk-Zutendaal portion was formally entrusted to the Charbonnages de Winterslag, and a royal decree of 5 October 1931 reunited both concessions into a single holding, enlarged in 1949 by division of coal reserve B to 5,633 hectares. After the war Winterslag was associated with the Walloon steelmakers Espérance Longdoz and Cockerill before being absorbed into the KS: Kempische Steenkoolmijnen, the consolidated Kempen mining company.

The mine closed on 31 March 1988. Several months before closure the colliery had recorded its highest ever single-day production. After closure the coal washing plant, brick works, workshops, and cooling towers were demolished. The winding house, the lamp room and showers building, and the directorate building were retained. The complex received monument protection in 1993. In 2001 the city of Genk acquired the site from LRM (Limburgse Reconversie Maatschappij). In 2005 the name C-mine was inaugurated for the creative and cultural campus taking shape on the former mine site. In 2008 Euroscoop took over the former lamp room and shower halls to build a cinema complex. In 2010 the city of Genk resolved to locate its cultural centre on the site. The energy building became a reception and conference space with a theatre and smaller auditorium in its flanks. The former stables function as business premises. Porcelain artist Pieter Stockmans made the former warehouse into his studio and living space. The LUCA School of Arts built a campus adjacent to the site. The spoil heap, 163 metres high, was converted into a public walking area. The C-mine Expeditie, an interactive underground experience trail through a former air passage of the mine, was established as the mining heritage attraction on the site. Visitors can climb the surviving 60-metre headframe for panoramic views.