Former slate mine site at Bel-Air de Combrée, now part of Ombrée d'Anjou, with residual industrial structures surviving in a partly revegetated setting.
The Puits de la Forêt at Ombrée d'Anjou designates the slate mine workings at the sites of La Forêt and Bel-Air in the former commune of Combrée, now absorbed into Ombrée d'Anjou, in Maine-et-Loire. Slate extraction in the Combrée area is known from at least the eighteenth century. The Société des Ardoisières de La Forêt opened the first quarry in 1876 to exploit the fond Sainte-Marie; underground extraction began around 1880.
The Commission des Ardoisières d'Angers established a competing operation at the Bel-Air site in 1896, sinking the first deep shaft to 195 metres. It acquired the La Forêt workings after their failure in 1908. Subsequent shafts included the puits N°2 at 160 metres in 1906 and a puits N°3 at 106 metres in 1942, with puits N°4, N°5, and N°6 following.
The Commission des Ardoisières d'Angers was later absorbed into a larger corporate structure. Extraction ceased in 1982. A small metal headframe survives on the site, set among birch and regenerating vegetation.
The substantial workers' cité, with its chapel-turned-church and school, was built from around 1900 onward.
The ardoisière workings at Combrée occupy the Segré syncline, in the westward continuation of the Misengrain slate deposit at Noyant-la-Gravoyère. The deposit belongs to the same Precambrian schist complex that underpins the principal Anjou-Mayenne slate industry centred on Trélazé. Slate extraction in the broader Combrée area was active from at least the eighteenth century when Combrée was listed among the principal Angevin centres of slate production, alongside Angers, Saint-Barthélemy-d'Anjou, Trélazé, and La Pouëze.
Exploitation in the Combrée-La Forêt territory began in earnest on an industrial scale in the 1840s with open-cast quarrying. The Société des Ardoisières de La Forêt was formed and opened a quarry in 1876 to exploit the fond Sainte-Marie, an area that had been worked as an open-cast quarry since around 1840. In 1880 the Société opened the carrière Saint-Joseph on an open-cast basis, but this collapsed within a few months.
In 1883 the Sainte-Marie quarry was halted. Underground extraction at the La Forêt site began around 1880. On the adjacent Bel-Air site, the Commission des Ardoisières d'Angers established a new competing operation in 1896, placing themselves in direct competition with the Société Ardoisière de l'Anjou, then the owner of the Misengrain slate workings.
The Commission des Ardoisières d'Angers sank the first shaft at Bel-Air in 1896, reaching a depth of 195 metres. In 1906 the second shaft, puits N°2, was sunk to a depth of 160 metres. Simultaneously with the development of the Bel-Air shafts, the Commission des Ardoisières d'Angers constructed a workers' cité from around 1900 onward.
Recognising the remoteness of the Bel-Air site from the bourg of Combrée and the substantial number of workers required, the company equipped the cité with a chapel that later became a parish church in 1904, a presbytery, and schools for boys and girls. By 1930, the Commission des Ardoisières d'Angers had developed the cité to approximately 300 dwellings. By 1908, the Société des Ardoisières de La Forêt at the neighbouring La Forêt site had gone into failure, and the Commission des Ardoisières d'Angers absorbed the La Forêt workings.
In 1942 a third shaft, puits N°3, was sunk at 106 metres depth. Puits N°4, N°5, and N°6 were subsequently sunk before cessation of activity. The headframe of the puits N°3 was demolished in the 1970s.
By 1973 the Commission des Ardoisières d'Angers — which had by that date become one component of the industry's consolidated structures — represented the first rank in the French slate industry, with its production accounting for 60 per cent of national output and 35 per cent of world production. In 1991 the Société Ardoisière de l'Anjou, owner of the Misengrain workings, attempted to match Spanish competition in the late 1980s but collapsed. The Bel-Air and La Forêt operations at Combrée closed in 1982.
Most surface buildings were subsequently demolished, but a small metal headframe survives at the site, set in regenerating vegetation among birch trees and lichens. The site's location beside the forêt d'Ombrée, for which the modern commune is named, means that the remaining structures are now enveloped by regrowth.