The age-old exploitation of slate has shaped the landscape of Trélazé. Today, the disused opencast quarries, slag-heaps and numerous pit-head frames (nowhere in France are there so many still standing) bear witness to its productive history.
However the mines continue their activity today and the Angers-Trélazé Slate Mining Company produces high quality slate with a worldwide reputation and now mostly used for the restoration of historical monuments and major landscape...