Monument record MDR7368 - High Rake and Deep Rake, north-west of Bleaklow Farm, Great Longstone

Deep Rake, with High Rake and Watersaw Rake is one of the largest mineralised zones in the orefield. It extends 4 miles from Cressbrookdale before disappearing under shale at the Calver-Hassop Road. It had been extensively worked from the medieval period. By 1750 most underground working had ceased and only heap working was being carried out. Now completely opencasted for fluorspar and barytes. (1) Open cut resulting from extensive dragline excavation along the main vein which crosses Longstone Edge from west to east. South facing north face is very fractured and began to collapse in 1991 endangering two Bronze Age burial mounds close to the north edge (SMRs 6431 and 6432). The rock face was blasted for safety reasons 1992-3 by Laportes. The cause of the collapse was attributed overhanging rock (1 million ton lump) exacerbated by underground mining for fluorspar and by open excavation of the rake. (2) The post medieval and earlier lead mining remains of Deep Rake / High Rake that once ran through this holding from east to west have been entirely removed leaving deep holes and modern opencuts in their place. In parts the holes have been backfilled and landscaped. In other parts the rake is still being worked. (3) Photographic record. (4, 5) It was stated in 1887 that 'chert is being raised in the Deep Rake on Longstone Edge, the limestone forming the walls of the old open cast workings at the east end of the vein having been to a great extent coverted into silica in the neighbourhood of the vein.' This was probably at Calver Peak Chert Mine which, according to the Inspector of Mines, was owned by Joseph Millington of Calver and recorded until 1899, although apparently not worked underground after the 1880s. On 30th October 1908, the Derbyshire Quarries Company Ltd informed the Barmaster of the King's Field that they were quarrying chert in the Hassop Estate. (6)