Surviving metal headframe of the puits N°26 des Fresnais at Trélazé, the twin to the adjacent puits N°25, both remaining as paired headframes from the former Fresnais ardoisière sector.
The puits N°26 des Fresnais at Trélazé, Maine-et-Loire, carries a metal headframe similar in form to that of the adjacent puits N°25, together constituting the two remaining chevalements from the Fresnais sector of the ardoisières of Trélazé. The Fresnais exploitation, along with the Grands-Carreaux, formed the two principal underground extraction areas of the Ardoisières d'Angers at Trélazé. The Fresnais sector operated via both underground puits, of which the puits N°26 formed part, and a 3-kilometre descenderie that by 2007 was producing 6,000 tonnes of schiste ardoisier per year.
The usine des Fresnais on the same site handled the transformation of slate blocks into finished products. The Fresnais descenderie closed in 2009. The Ardoisières d'Angers — controlled by Imerys — announced definitive closure on 25 November 2013 and the last workers left on 29 March 2014.
The puits N°26 headframe is named by Wikipedia among the six surviving chevalements of Trélazé, paired with the puits N°25 as two similar structures from the same sector.
The Fresnais sector of the ardoisières of Trélazé was one of the two major underground extraction sites of the Société des Ardoisières d'Angers in the late twentieth century, alongside the Grands-Carreaux. Slate extraction at Trélazé is documented from the ninth century, with the first recorded open-cast quarry at Tire-Poche in 1406. The Commission des Ardoisières d'Angers was formed in 1891 and became the Société des Ardoisières d'Angers in 1963.
Open-cast working ceased entirely in 1899. The Fresnais exploitation was organised around a complex of underground puits, including the puits N°25 and puits N°26, and a 3-kilometre descenderie. The usine des Fresnais was the processing facility where slate blocks extracted from the underground workings were split, trimmed, and prepared for despatch.
At the end of the 1960s the Ardoisières d'Angers represented 60 per cent of French slate production and operated sites at Trélazé, Combrée, La Pouëze, Saint-Saturnin, Renazé, and Ploermel. By 2007, the Fresnais site produced 6,000 tonnes per year while the Grands-Carreaux produced 9,000 tonnes, for a combined company capacity of 15,000 tonnes with 220 employees, 60 of them underground. The Fresnais descenderie closed in 2009.
From that year the puits N°7 de Monthibert at the Grands-Carreaux was the sole active extraction point in France. The production decline had been continuous: from 80,000 tonnes in 1982 to 40,000 tonnes in 1990, 25,000 tonnes in 1997, and 15,000 tonnes in 2007. On 25 November 2013 the Ardoisières d'Angers announced closure, citing exhaustion of the gisement; the company employed 153 workers at that date.
The plan social was signed 28 March 2014 and definitive closure was effective from 29 March 2014, ending 123 years of continuous operation. The metal headframe of the puits N°26 des Fresnais is among the six chevalements métalliques identified by Wikipedia as surviving from the eight that once stood at Trélazé. The puits N°25 and N°26 headframes stand as a paired industrial monument on the former Fresnais carreau.
The former ardoisière territory at Trélazé was classified as a zone naturelle d'intérêt écologique, faunistique et floristique following closure.
