Summary

Tin mill 80m south of Glaze Meet.

Source: Historic England

Details

This record was the subject of a minor enhancement on 5 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.

Source: Historic England

Reasons for Scheduling

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 drystone 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. At the blowing mill the cassiterite may have been washed a final time before being put into the furnace together with charcoal. To smelt tin the temperature within the furnace had to reach 1150 degrees C. This was achieved by blowing air through the furnace using water powered bellows. 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.

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. The tin mill south of Glaze Meet unusually contains evidence for both activities within one building, more often the two processes are carried out in separate buildings even if they are closely located. Since tin is limited to Cornwall and Devon in England any surviving buildings associated with its processing are both rare and geographically limited. As such this tin mill is a very unusual and important structure which will provide important archaeological evidence for tin processing activities.

Source: Historic England

Sources

Books and journals
Butler, J, Dartmoor Atlas of Antiquities, Volume Four – The South-East , (1993), 99
Other
PastScape Monument No:- 441960

Source: Historic England