Former primary extraction shaft of the Ardoisières de Misengrain at Noyant-la-Gravoyère, retaining its metal headframe, winding engine house, and associated atelier buildings.
The Puits No.7 at Segré-en-Anjou Bleu is the last active extraction shaft of the Ardoisières de Misengrain, located at the lieu-dit of Misengrain on the commune of Noyant-la-Gravoyère, now part of Segré-en-Anjou Bleu in Maine-et-Loire. The puits N°7 was foncé to a depth of 194 metres and equipped with an electric extraction machine in 1934. It was the final shaft in operation at Misengrain and the sole shaft used when the Ardoisières d'Angers took over the failing Société Ardoisière de l'Anjou in 1987.
The puits N°7 is equipped with a metal headframe and a winding engine house in brick, and is linked by a voie ferrée to the ateliers of debitage and fente. A conveyor belt ran between the debitage atelier for block cutting and the covered fente workshops. An additional south-facing atelier was covered in shed form.
Extraction ceased definitively in 1999. The site retains the metal headframe of the puits N°7, the covered recette, the winding engine house, and the ateliers. The site was in use by a demolition company as of the survey period, which enabled the preservation of numerous buildings.
The Puits No.7 is the principal and last extraction shaft of the Ardoisières de Misengrain in the commune of Noyant-la-Gravoyère, now part of Segré-en-Anjou Bleu since the communal merger of 2016. Like the adjacent puits N°6, it is sited in the Misengrain valley within the Segré syncline of Precambrian schiste ardoisier. The history of the workings leading to the sinking of the puits N°7 follows the same sequence as that of the puits N°6: the seventeenth-century attestation of working, the 1833 company foundation, the 1860 éboulement and dissolution, the 1864 English purchase and first underground shaft at 70 metres, the catastrophic accident of 15 November 1888 killing 18 workers, the purchase in 1894 by the Société Ardoisière de l'Anjou for 425,000 francs, and the 1896 faillite and acquisition by the Ardoisières d'Angers with the creation of the Société des Ardoisières du Haut-Anjou.
Under the Société des Ardoisières du Haut-Anjou, multiple shafts were progressively sunk at the Misengrain site. The puits N°7 was foncé to a depth of 194 metres and received an electric extraction machine in 1934. It became the principal extraction shaft of the site.
The metal headframe of the puits N°7 is equipped with a covered recette, and connected by a voie ferrée to the ateliers for debitage of the slate blocks and to the covered ateliers for fente, the manual splitting of the schiste into finished ardoises. A transporteur à bande ran between the debitage atelier and the fente workshops. An additional atelier covered in shed form stood to the south.
The winding engine house was constructed in brick. Up to 800 workers were employed across the Misengrain site at peak output. In the 1960s, the ascending method of chamber working was replaced by the descending method, allowing chambers larger than 1,000 square metres and more than 20 metres deep to be worked mechanically by saws, meilleuse, and haveuse, with explosive retained only for opening chambers.
Extraction and fabrication continued at the puits N°7 until the faillite of the Société Ardoisière de l'Anjou in 1986, when approximately 300 workers were made redundant. In 1987 the Ardoisières d'Angers took over the Misengrain workings, operating on the puits N°7 as the sole remaining extraction shaft. The workings closed definitively in 1999.
After closure, the site was occupied by a demolition company (Occamat), whose use of the buildings enabled their preservation. As of the Exxplore site survey, the atelier buildings were destined for a new use. A portion of the workers' cité ouvrière, erected from the 1880s by the Société des Ardoisières de l'Anjou and subsequently expanded, has been rehabilitated as a hotel-relais.
The site of the puits N°7, with its metal headframe, covered recette, brick winding engine house, debitage atelier, fente ateliers, and conveyor structures, constitutes one of the better-preserved colliery surface complexes in the Anjou slate industry.