Chessy copper mines
Chessy, Villefranche-sur-Saône, Rhône, Auvergne-Rhône-Alpes, France
Anciennes mines de cuivre de Chessy
Key Information
Do not enter mining areas without proper authorization.
Chessy copper mines, located in Chessy, Rhone, France, are about 22 km from Lyon and known for azurite, a type locality mineral.
The mines, active from the Middle Ages to 1875, produced over 117 minerals, including cuprite and malachite, in altered dacitic lavas and Triassic sediments.
The geological setting involves hydrothermal mineralization, with different mine sections like the Blue Mine famous for azurite vugs.
The mine is now closed, with dumps searched by a mineralogical club, and the area features a historic castle and is part of a wine region.
The climate is temperate, not directly impacting mineral production, but enhancing the area's appeal for visitors.
Location and History
Geographic Context
Chessy lies in the Rhone department, Auvergne-Rhone-Alpes region, about 22 km from Lyon, a major French city. It's surrounded by small villages like Bagnols and Theize, offering a rural charm, but no other famous mineral localities are nearby.
Mining Legacy
Operational from the Middle Ages until 1875, the mines closed long ago, with current activities limited to dump searches by the Association Minéralogique de l'Arbresle Chessy-les-Mines (AMAC). The Blue Mine, opened in 1811, is renowned for its azurite vugs, adding to its historical significance.
Mineral Wealth and Geology
Mineral Highlights
The mines are famous for azurite, a type locality mineral, alongside cuprite, malachite, and over 117 other valid minerals. These secondary copper minerals, formed through oxidation, are prized by collectors for their beauty and rarity.
Geological Insights
The site features "stockwerk" mineralization in altered soda-dacitic lavas from the Devonian period, covered by mineralized Triassic sediments (clay and sandstone). Hydrothermal fluids played a key role, with different mine sections like the Yellow Mine (primary sulphides) and Blue Mine (oxidized ore) showcasing varied geological processes.
Cultural and Environmental Notes
Local Culture
Chessy boasts the Château de Chessy, a historic castle, and is part of the Rhone department, known for its wine production, offering potential for wine tours and tastings.
Climate and Ecology
The area has a temperate climate, typical of France, with mild summers and cool winters. While not directly linked to mineral formation, it enhances the region's appeal for tourism and exploration.