Date: 1888
The principal, and indeed the only one largely worked, is that known as old Delabole quarry, which has supplied roofing and flooring slates for the past 300 years.  Steam power was introduced in 1837, and the output increased to such an extent, that in 1847 sive steam engines and 1000 persons were employed.  In 1882 the workmen numbered 350, and the quantity of manufactured slates, slabs, <fec.