SPREAD across the slopes of a 1,500ft hill on South West Dartmoor are the conspicuous remains of one of the moor's largest and most prosperous 19th century tin mines — Eylesbarrow, as it is usually called today.

Documentation for tinworking in the Eylesbarrow area survives from the 16th century and it is likely that tinners were active there at least as early as the 12th century.

Operating between 1804 and 1852, the 19th century Eylesbarrow tin mine was subject to several spelling variations, among the most common being Ellisborough, Ailsborough and Hillsborough.

Some of the company names were simply renderings of the hill name, whereas others were doubtless aimed at boosting speculator support by introducing the solid sounding 'Consols' or 'Consolidated' and thus bringing to mind the pleasing associations of certain spectacularly successful mining ventures, as well as a government stock of unimpeachable worth.

The mine is easily accessible by way of Sheepstor village to Burracombe Gate near Gutter Tor, followed by a walk of about one mile over a well-worn miners' track.

A wealth of visible remains either side of the track include a hillside sequence of water-wheel operated stamping mills which crushed the ore, their associated dressing floors containing shallow pits for concentrating the finely crushed black tin (cassiterite) for smelting, a smelting house — the last one working on moorland Dartmoor — a massive wheelpit built in 1847 to accommodate a 50ft diameter pumping wheel and a somewhat earlier engine-wheel house (dating from 1815) which contained a smaller wheel, also for pumping water from deeper parts of the mine.

Transmission of power between the pumping wheels and underground pumps located in shafts at higher parts of the mine site was achieved by alignments of reciprocating flatrods, as was common practice in Devon and Cornwall at the time.

At Eylesbarrow, the paired granite flatrod supports, often streaked with hardened black residue of lubricant used to grease the cast iron pulleys, are well represented among surviving structures.

Traceable infrastructure comprise trackways, tramways and leats — the water supply chiefly conducted from the River Plym and its tributary, the Langcombe Brook.

The longest of the leats curved round Higher Hartor Tor to feed a long narrow hillside reservoir beside the main track. It is here, a 1,300ft vantage point affording magnificent views of Plymouth Sound and East Cornwall, that the mine manager James Henry Deacon kept a rowing boat to entertain his friends.

The small industrial community had several ancillary buildings: a barrack house, sample house, two powder houses, timber house (probably carpenter's shop and store), blacksmith's shop, a turf house for storage of peat as domestic fuel and an account house.

Some time after 1823 the latter became a spacious dwelling for the mine manager/captain.

The ruins of this building complex are situated where the track starts levelling off near the top of the rise and part of this area was enclosed in the late 1830s or early 1840s to make fields and a garden.

Most underground activity centred on three closely adjacent, parallel, east-west lodes at a comparatively shallow depth that were worked by adits (levels driven into the hillside) and shafts. The longest adits were cut on the course of the main lodes for a distance of 3,600ft.

In total there were 30 shafts, including at least six in the Crane Lake area at the easternmost part of the huge three by two mile composite sett granted for working. The deepest shafts were about 325ft. It is likely that much of the Eylesbarrow ore was of very fine quality.

Eylesbarrow was most unusual in having its own smelting house, as by the 19th century, metalliferous mining and smelting had typically become separate industries.

It worked from 1822 to 1831, prior to which concentrate would have gone to Cornwall for smelting — perhaps to Calenick near Truro.

Records exist of the quantities of tin smelted at Eylesbarrow and of the different grades of metallic tin produced — grain, common and refined — which support field evidence of both a blast and a reverberatory furnace. Grain tin was a high quality product particularly sought by the Welsh tin plate industry which by 1815 had become a major importer of tin metal.

Associated with the blast furnace is a 70ft length of horizontal flue designed to capture particles of black tin concentrate driven from the furnace by the forced draught.

This obviated the somewhat drastic earlier practise, described by Richard Carew in The Survey of Cornwall (1602), of burning the thatched roofs of blowing houses 'once in seven or eight years' to recover lost tin 'and find so much of this light tin in the ashes as payeth for the new building with a gainful overplus'!

During the ten-year period of its operation, the smelting house produced 276 tons of metallic tin in the form of 1,807 blocks each weighing approximately three hundredweights.

The blocks were taken to Tavistock for coinage (weighing, assay and stamping). Not all of this had originated from the Eylesbarrow workings, some concentrate having been sent from the Vitifer and Bottle Hill mines for smelting.

The tin smelter was Walter Wellington. Earlier he had been fortunate to find gold at Sheepstor. But in his notes to NT Carrington's descriptive Dartmoor poem he tells us that 'Prills [pearls] of gold have been found in the river and other streams below Sheepstor,and enough of that valuable substance was discovered four or five years since [ie circa 1821] by one person (Wellington, a miner) as to sell in Plymouth for about £40'.

Evidently this followed long-established practice, since Carew (1602) states that 'Tinners do also find little hopps among their ore, which they keep in quills and sell to goldsmiths '.

Among details depicted on an early 19th century plan of the mine are two parallel lodes quaintly designated as 'North Dragon Lode' and 'South Dragon Lode'.

Against the latter, where it crosses the extensive Evil Combe streamwork, is an intriguing note stating 'a fiery dragon was seen to fall near this place'.

Aside from the thought that much of the area is bog and the incendiary monster would have been extinguished pretty soon, one is struck that as late as around 1820, a thoroughly workmanlike plan should record this item of, what must seem to us, attractively old-fashioned folklore.

Indeed, it is an echo of earlier records, like those of Thomas Tonkin, the Cornish scholar.

He died in 1724 leaving a number of unpublished manuscripts, including one on Carew's Survey containing the following note about mineral prospecting: 'Some say, that on a still night you may see fiery exhalations issue out of such places; and some again, that they see streams of fire to fall on them, which they call fiery dragons.'

The reference to fiery exhalations is probably alluding to will-o'-the-wisp, resulting from the combustion of the naturally produced gases phosphine and methane on marshy ground.

Furthermore, in R J King's The Forest of Dartmoor and its Borders (1856) we read that 'Marsh fires and nocturnal meteors are thought to hover above undiscovered mines: a most ancient — these 'fiery dragons' or 'tomb fires' were believed throughout Northern Europe to mark the hiding places of concealed treasure'.

The cessation of on-site smelting in 1831 marked a slowing down of Eylesbarrow's mining, when it entered a phase of irreversible decline.

Sadly, the last three companies failed in quick succession; the final closure being Thursday, September 30, 1852, when all materials and equipment were auctioned by Mr William Monk at 10 o'clock at the mine.