The economic upturn after the Franco-Prussian War of 1870-71 resulted in a renewed increase in slate production, where companies used more extensive pits. Production continued until the 1960s, when the competition from cheaper synthetic or imported slate resulted in production decline.
The economic revival following the Franco-Prussian War triggered an increase in slate mining activity, as firms expanded their operations to utilize more extensive pits. However, this expansion was eventually curtailed due to increased competition from more affordable synthetic or imported materials.