Former anthracite mine at Prunières with the surviving metal headframe of the puits des Rioux, conserved and labelled Patrimoine en Isère.
The Mines de La Mure at Prunières form part of the Houillères du Dauphiné coalfield on the Matheysine plateau in the Isère department. The principal installation at this site is the puits des Rioux, whose sinking began in 1942 under the name puits Henry de Renéville, in honour of a director of the Compagnie des Mines de La Mure. The shaft, 400 metres deep with a diameter of four metres, was completed in 1946 and served primarily for personnel and materials transport, linking the Villaret workings at Susville with the lower galleries of the gorges du Drac.
Following nationalisation in 1946 the shaft was renamed puits des Rioux and operated by the Houillères du Bassin du Dauphiné. It was equipped with a three-level cage driven by a 380-horsepower motor. Two fatal accidents occurred during the operational life of the shaft.
The puits des Rioux and its surface installations closed in 1984. The shaft's metal headframe remains standing at Prunières and has been conserved and labelled Patrimoine en Isère. A commemorative fresco was added to the site in 2021.
The puits des Rioux at Prunières is one of three principal shafts of the Houillères du Dauphiné coalfield, the others being the puits Sainte-Marie at La Motte-d'Aveillans and the puits du Villaret at Susville. The Matheysine anthracite deposit had been exploited since at least the thirteenth century, with formal concessions granted from 1805 and the Compagnie des Mines d'Anthracite de La Mure formed in 1856. The Prunières concession was one of the earlier concessions in the basin.
Sinking of the shaft at Prunières began in 1942. The Compagnie des Mines de La Mure named it the puits Henry de Renéville, in honour of one of the owners of the mine who had served as director from 1890 to 1934. During the sinking phase, a temporary wooden headframe was constructed. Sinking was completed in 1946. The shaft had a diameter of four metres and reached a depth of 400 metres, making it the deepest shaft in the Matheysine basin. It was equipped with a three-level cage for the transport of personnel and materials, driven by a motor of 380 horsepower manufactured by the ateliers Venot and Co with a CEM motor. The shaft served to connect the Villaret mining district at Susville with the lower galleries of the gorges du Drac, and also functioned as an air return for its level. A ventilation gallery, the galerie des Rioux, was sunk in 1949 for air circulation at this horizon.
Following nationalisation by decree of 28 June 1946, the shaft was renamed puits des Rioux and passed to the Houillères du Bassin du Dauphiné. The permanent metal headframe replaced the temporary wooden structure after 1946. The headframe is a riveted metal framework structure comprising an inclined face supporting two sheave wheels, emerging from a pithead building also constructed in metal framework with slag infill. In 2014 the headframe underwent renovation works including repainting.
Two fatal accidents occurred at the Prunières site during its operational life. On 16 January 1946, eight miners were killed. On 4 May 1971, a further eight miners were killed in a sudden gas outburst known as a dégagement instantané in the Devay district.
The puits des Rioux and its surface installations closed in 1984. Exploitation continued on the Villaret site at Susville until the final cessation of extraction on 28 March 1997. The puits des Rioux site has been conserved following closure and was labelled Patrimoine en Isère in 2015. The headframe, pithead building, winding machine, and ventilation fan have been preserved. The winding machine, a cylindroconical drum type, was damaged by metal thieves. In 2021 a large commemorative fresco was painted on the wall of the pithead building in memory of the victims of the 4 May 1971 accident. The site is not open for underground visits but the headframe and fresco are accessible externally.
