Surviving metal headframe of the puits N°25 des Fresnais at Trélazé, one of two similar chevalements remaining from the Fresnais ardoisière sector, closed as an underground operation in 2009.
The puits N°25 des Fresnais at Trélazé, Maine-et-Loire, carries a metal headframe that is one of two similar surviving chevalements from the Fresnais sector of the ardoisières of Trélazé. The Fresnais exploitation formed the second major production site of the Ardoisières d'Angers alongside the Grands-Carreaux, operating both an underground puits operation and a 3-kilometre descenderie. By 2007 the Fresnais site contributed 6,000 tonnes of schiste ardoisier per year to the company's output of 15,000 tonnes in total, alongside an adjoining usine des Fresnais for transformation of slate blocks into finished products.
The Fresnais descenderie closed in 2009, after which the Grands-Carreaux puits N°7 de Monthibert became the sole extraction site in France. The puits N°25 and the puits N°26 des Fresnais are named in the list of six surviving headframes that Wikipedia identifies from the eight that once stood at Trélazé. Their two similar metal headframes form a paired landmark on the former Fresnais carreau.
The Fresnais sector at Trélazé is the second major production area of the ardoisières of Trélazé after the Grands-Carreaux. Slate extraction at Trélazé is recorded from the ninth century for tombstones and from the eleventh century for roofing; the first open-cast quarry at Tire-Poche dates from 1406. The Commission des Ardoisières d'Angers was formed in 1891 from the principal Trélazé producers, becoming the Société des Ardoisières d'Angers in 1963.
The last open-cast quarries closed in 1899, leaving all extraction underground. At the end of the 1960s the Ardoisières d'Angers represented 60 per cent of French slate production and operated multiple sites, including the puits des Fresnais and the Grands-Carreaux within the Trélazé basin, as well as sites at Combrée, La Pouëze, Saint-Saturnin, Renazé, and Ploermel. The Fresnais exploitation within the Trélazé basin was organised around both underground puits operations, of which the puits N°25 formed part, and a descenderie of 3 kilometres.
By 2007, the Fresnais site produced 6,000 tonnes of schiste ardoisier per year via the descenderie, while the Grands-Carreaux produced 9,000 tonnes via the puits N°7 de Monthibert, giving a combined total capacity of 15,000 tonnes. The usine des Fresnais was the transformation plant where blocks of schiste were worked into finished ardoises. The Fresnais descenderie closed in 2009.
From that date the puits N°7 de Monthibert was the sole remaining active extraction point in France. On 25 November 2013 the Ardoisières d'Angers, controlled by Imerys, announced definitive closure citing exhaustion of the gisement. The plan social was signed on 28 March 2014 and closure was effective from 29 March 2014, ending 123 years of continuous activity.
The Wikipedia list of surviving Trélazé structures identifies six chevalements métalliques as remaining from the eight that had stood at the height of extraction; among these six, the puits N°25 des Fresnais and the puits N°26 des Fresnais are both named. The two similar metal headframes of the puits N°25 and N°26 constitute a paired heritage presence at the former Fresnais carreau. The former ardoisière territory, including the Fresnais site, was classified as a zone naturelle d'intérêt écologique, faunistique et floristique following closure.
