Dartmoor has a long history of mining for tin and other metalliferous ores. The remains of some of these old mines are still clearly visible in the remote areas of open moorland but in other, more populated areas, very few signs of the mining legacy remain.
An essential part of investigating old mines sites is to carry out a mining desk study. This includes the research of old mine plans and other documentary records together with a walkover inspection to check for any visible evidence of old workings (such as mine shaft, adits, spoil heaps, old buildings and structures etc). The old mine plans are often incomplete or of poor accuracy, so the walkover inspection is an important part of the study, helping to draw together the various elements of research and producing a more complete picture of the likely extent of the old mine workings.
Sometimes, when appropriate safety precautions have been implemented, it is possible to gain entry to the underground mine workings. At a site on Dartmoor, Frederick Sherrell Limited carried out an underground survey of the old mine workings which was then used to assist in the assessment of stability of the old mine workings and the ground above. The survey confirmed the presence of a mine shaft that was subsequently uncovered at the ground surface and permanently capped.