CHEVALEMENT DU PUITS DE LA TRANCHÉE

Built in 1874 and 1875 by architect Edmont Heusschen, the Puits de la Tranchée headframe is located in the coal seam of the Basse-Loire basin. Prior to its construction, a carboniferous mining site had existed since 1541. Then, in 1743, the Lord of Montjean obtained the royal privilege of modernizing coal mining at Montjean-sur-Loire. Architecturally, the site comprises the Puits de la Tranchée, topped by a headframe, a sevenfold lime kiln, a mine and quarry linked to the seven kilns by a railway, the steam engine building and a port. The Puits de la Tranchée headframe is the most powerful (32.29 meters high) of the thirteen stone headframes still standing in France. It framed a wooden structure supporting the raw material hoist and descended to 178.5 meters below ground to feed the seven furnaces, via a pulley system that brought the coal bags to the surface. These kilns fired the local limestone before shipment. Production peaked in 1891 with a total of 16,206 tonnes. Coal mining (totalling 500,000 tonnes) and lime production ceased in 1892. The entire site has been listed as a historical monument since 2004.