The ovens of Valettes were inaugurated in 1905, the concession having been obtained the same year by the Metal Mining Company of Aveyron. Its perimeter extends between Saint-Jean du Bruel and Causse-Bégon and the works concern "La Gardiole", the Valettes (above the ovens), "Les Baldy" and "L'Yfer" above the brook called Saint-Gleys between Barjac and the confluence of Valettes. The main ore is constituted by calamine containing 35 to 40% zinc. The five furnaces are intended for enrichment by the so-called reduction method.As the research progresses, the results soon turn out to be disappointing, because if from 1901 to 1904, 800 tons of calamine are extracted, 390 tons in 1905, 435 tons in 1906, it is treated only 160 tons in 1909. Work must stop in 1914 and will never be resumed.After their abandonment, the five ovens will serve as a quarry. The three openings of the ovens are each coated with two rows of refractory bricks. These bricks will be used by a local artisan to make small metal ovens for baking bread, to keep cozy warmth under the feet and beds of the inhabitants of St-Jean, and finally to build the heating fireplace of the church. .Source: written by Claude Bouteiller, revue Causses et Cévennes du Club Cévenol n°4-Août Septembre Octobre 2004