Tin mining

NOW that the clocks have moved forward into British Summer Time and hopefully we have some warmer weather to go exploring, I thought it might be interesting to tell readers about the working of tin on Dartmoor.

This industry took place over an 800-year period and has left behind the most striking impression on the landscape. Although the written records for tin mining go back to the 12th century it is very likely that tin was being extracted in prehistoric times.

The earliest medieval workings involved stream working where alluvial tin from stream and river beds was extracted by a process similar to gold panning. This process has left behind characteristic spoil heaps in the form of small stones; some are arranged in roughly parallel lines with retaining stone walls.

By the 15th century the below ground tin lodes were being worked by opencast working leaving behind deep V-shaped gullies usually running east to west. Associated with these early workings were tin mills; rectangular stone buildings situated close to streams which fed leats (artificial water channels) to bring the water for waterwheels which drove the machinery to crush the tin ore and to work the bellows used for smelting the tin.

By the 18th century more sophisticated techniques were being used, with water and leats providing the source of power for large wheel pits situated close to mine shafts. Also associated with this period of hard rock mining were a variety of mine buildings; the last working mine on Dartmoor closed just before the Second World War.

Copper, lead and iron have all also been extracted from around the edge of the moor. In many instances these mines, which date from the 18th and 19th century, produced more than one product, and their archaeological remains are similar to those associated with tin working — with the addition of the engine houses used to pump the shafts free of water.

Tin mining continued at certain sites well into the 20th century and there are people still alive who can remember going underground to work these mines. Evidence of these early workings can be seen in most river valleys as heaps of rubble and waste which, in many cases, have become overgrown by grasses and bilberries.

From the earliest days of extracting tin from moorland streams through to the shaft mining of the 19th century, tin mining has had a powerful influence on Dartmoor — so much so that tinners on the moor had their own parliament and could make their own laws. In fact the extraction of tin, through its various methods, has, over the centuries, had a huge influence in shaping the landscape we know and love today.

The majority of the remains attributable to tin extraction are recorded on the Dartmoor Ordnance Survey map 28 and in more recent years some of the features have needed to be fenced around by landowners to avoid grazing animals, walkers and dogs falling in to them.

Visitors to the Dartmoor National Park Visitor Centre in Princetown can see a fascinating exhibition by the Dartmoor Tinworking Research Group, telling the story of tin mining on Dartmoor.

It will also highlight some of the group’s current projects, and celebrates 25 years since the Dartmoor Tinworking Research group was founded. The exhibition runs at the visitor centre until May 25, 2016.