Summary
Tin mill at Gobbet Tin Mine 560m south of Sherberton.
Reasons for Designation
Dartmoor is the largest expanse of open moorland in southern Britain and, because of exceptional conditions of preservation, it is also one of the most complete examples of an upland relict landscape in the whole country. The great wealth and diversity of archaeological remains provide direct evidence for human exploitation of the Moor from the early prehistoric period onwards. The well-preserved and often visible relationship between settlement sites, major land boundaries, trackways, ceremonial and funerary monuments as well as later industrial remains, gives significant insights into successive changes in the pattern of land use through time. Blowing mills (also known as blowing houses) survive as rectangular buildings served by one or more leats and are characterised by the presence of granite blocks with moulds cut into them - bevelled rectangular troughs known as mould stones - and on occasion by the square or rectangular stone built base of the furnace itself. During the medieval and early post-medieval period, black tin (cassiterite) extracted from streamworks and mines, was taken to blowing mills to be smelted. Once the tin had become molten, it flowed from the furnace into a float stone and was ladled into the mould stone, in which it cooled to form an ingot of white tin. During the same period, tin ore extracted from mines was taken to stamping mills to be crushed, using heavy iron-shod stamps attached to the lower end of vertical wooden posts called lifters, which were raised using a water-driven rotating axle. Thus raised, the stamps fell under gravity onto the ore, crushing it between the stamp's head and a hard slab of rock called the mortar stone. There were two types of stamping machinery. The first, known as dry stamps, involved the crushing of the ore without use of water, the second, wet stamping utilised a constant flow of water to carry the tin crushed by the stamps through a fine grate into a channel, to be carried in suspension to a settling pit from where it could be collected for dressing. Crazing mills crushed ore between two circular stones like traditional grist mill stones. The tin mill at Gobbet Tin Mine 560m south of Sherberton is extremely unusual, not only is tin processing restricted to Devon and Cornwall, but this is the only known tin mill on Dartmoor to contain both upper and lower crazing stones and no documentary evidence for the presence of a crazing mill on the moor has yet been found. It also exhibits all the major elements of tin processing containing mould stones, mortar stones and evidence for a furnace.
History
See Details.
Details
This record was the subject of a minor enhancement on 18 November 2015. This record has been generated from an "old county number" (OCN) scheduling record. These are monuments that were not reviewed under the Monuments Protection Programme and are some of our oldest designation records.
Legacy
The contents of this record have been generated from a legacy data system.
Legacy System number:
DV 1004
Legacy System:
RSM - OCN
Sources
Books and journals Other
Legal
This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Culture, Media and Sport.
End of official list entry
