The strongly cleaved volcaniclastic units (tuffs) within the BVG have in contrast locally produced good quality slates that have been widely quarried and more recently extracted by mining. Several different bands of slate have been worked across the outcrop, for instance at Buttermere, along Borrowdale (Honister, Yewcrag, Rigg Head and Castle Crag) and from the Duddon Estuary up to Mosedale (including Broughton Moor, Kirskstone and Coniston). Light green, silver grey and blue-black varieties have all been worked. They have been used for roofing both in the Lake District and elsewhere in the United Kingdom. The Honister Slate Mine is the only mine in the Lake District still producing slates of this type.