Poldark Mine - History
-Prehistory to 1972 - Poldark the Heritage Site -The Mine - Mineralisation
An Overview of Mining History
Cornwall has a history of tin production dating from at least 1800 BC. From the Bronze Age the County was an important producer of tin, which when mixed with copper forms the alloy bronze. Until the 14th century tin was produced from rich alluvial deposits primarily in the St. Austell and Wendron districts. As these deposits were being worked the 'tin streamers' often came across the outcrops of rich tin lodes which they would occasionally work.
This was particularly so in the valley of the River Cober in the parish of Wendron where there are a number of recorded instances of the tin streamers working the river alluvials discovering tin lodes which they then began to mine underground. A typical example of this early working of tin mines is to be found at Poldark Mine who's Wheal Roots Lode was discovered and worked by the tin streamers in the bed of the River Cober around 1720. Explosives were not used to blast rock in the mines of Cornwall until 1689, by which time the Duchy's mining industry was well established with many deep mines working.
When a local mine, Wendron United Mine, was reopened in 1908 evidence of 17th century mine workings were found in the form of traces of lime setting and a pipe dated 1650. There were three methods of mining in use prior to the introduction of the use of explosives. Where the rock was soft iron picks and wedges were used to slowly remove the rock. Where the rock was hard the miners either built a large fire against the rock face to heat the rock and then poured cold water onto the hot surface causing the rock to crack. They would then use iron wedges to break the rock apart. The other method was to bore a hole using an iron bar which they would beat with a heavy hammer and then fill the hole with lime mixed with water. Again the effect was to cause the rock to crack. All this work was carried out in smoke filled tunnels with only the light from a tallow candle.
By 1710 Balcoath, a mine known to have been working in 1640 and situated a mile from Poldark, had installed the first steam engine in the County. It was to be almost another hundred years before Cornish engineers were able to develop the steam engines into the most efficient steam driven pumps in the world. The development of the steam engine enabled Cornish mines to go much deeper than any mines had previously been able to do and resulted in the development of new mining techniques which were the foundation of the world's modern mining industry.
By the 1840's Cornwall was the world's largest producer of both tin and copper, supplying three quarters of the worlds needs for both metals and in addition large quantities of arsenic, lead, silver, uranium and to a lesser extent iron, tungsten, bismuth and cobalt. It was from the South Terras Mine near St. Austell that Madame Currie obtained the uranium for her experiments. With the discovery of rich deposits of minerals overseas, often worked by Cornish miners, the industry in Cornwall fell into decline in the 1860's and 70's. The last Cornish tin mine to close was South Crofty, where almost four thousand years of tin production in the County ended in 1998.
By the 1820's Cornish mining skills and Cornish manufactured pumping engines were in great demand throughout the world and there followed over 100 years of contract mining overseas and emigration to every continent. The result is that the Cornish engine houses, so familiar to visitors to the Duchy, are also landmarks in many foreign countries, from the silver mountains of Mexico to Australia, the plains of Spain to the gold fields of South Africa and even on tropical Caribbean islands. Cornish pasties are made daily in the United States, Canada, Mexico and Australia and the largest gathering of Cornish people and their descendants takes place every two years in Australia ! The early history of Poldark is lost in the mists of time. Certainly before recorded history tin was being worked in the gravels of the Wendron and Porkellis Valleys which were the most important source of alluvial tin in west Cornwall.
THE EARLY HISTORY OF POLDARK Prehistory - 1972
THE SITE
The early history of Poldark is lost in the mists of time. Certainly before recorded history tin was being worked in the gravels of the Wendron and Porkellis Valleys which were the most important source of alluvial tin in west Cornwall.
Evidence of the early working for tin was discovered on the site in the winter of 2000 when heavy winter rains exposed mortar stone depressions in granite bedrock in the main car park. The use of mortar stones to crush the rich alluvial tin ore ready for smelting dates from prehistoric times. The practice was replaced by the early tin stamps that were introduced around the 12th century. The granite exposure is the only one of its type so far discovered in Cornwall and is evidence of working for tin on the site some time between 2000 BC and 1200 AD.
An artist impression of the Poldark Mortar Stone in use
The first recorded tin stamping mill on Duchy land, and the earliest so far recorded in Cornwall, was erected at Poldark before 1493, when John Trenere, freeman, held a lease to the stamps and watercourses in Lower Trenere1
1493 lease - original held at the Duchy of Cornwall Record Office
In 1500 his neighbour had erected a new mill, described as a 'scoffe myll'. The name was derived from the Cornish 'scovan', the rich part of a tin lode, and may give a clue to the approximate date of the commencement of underground mining in the Parish. Within Poldark Mine there are levels that were made using a pick, indicating that they were driven before the introduction of the use of explosives in Cornish mines in 1689. As noted above records show that the Poldark site was a tin stamping mill before 1493. (1. Duchy of Cornwall Records Office)
The Company holds the leases and conveyances from 1801 to the present day which clearly show that the site continued to be used for tin dressing until 1885 when it was purchased by the Trenear Dairy Company. In 1801 a lease was transferred from William Tremayne to Joseph Edwards, the site then owned by a Thomas Hocker. Various leases show continued use as a tin stamps through to 1854 when the Adventurers of Wendron Consols Mine took up the lease, however in correspondence to the owner they described the water wheel as 'fit only for a Christmas bonfire' ! suggesting that the stamps had stood idle for some time.
The tin processing equipment on the site was improved upon to treat the ore raised from the Wendron Consols mine and, following its closure, the lease was taken up by the Adventurers of another local mine, Great Wheal Lovell. The 1885 conveyance describes the site as 'that stamping mill known as Trenear Stamping Mill lying and being at Trenear Wollas in the Parish of Wendron and the stamps plot and dressing floors therto adjoining and all leats, waters, watercourses, easements and appurtenances. All which premises were formerly in the occupation of Wendron Consols Adventurers and afterwards of Great Wheal Lovell Adventurers.' The water wheel pit and leats supplying water, which run alongside our main car park, to them have been in continuous use for over 500 years, having been used by the dairy company until 1970 to power all machinery in its works and since that time as part of the heritage attraction.
Poldark Mine - The Mining Heritage Site 1972-
Poldark Heritage site started life in 1972 when Peter Young, a retired Royal Marine, attended an auction in the local hamlet of Trenear with his young daughter Carol. The purpose was to buy a much needed wardrobe. The local forge, Wendron Forge, came up for auction and as the price very slowly rose to £10 Peter thought that the forge was going for a bargain price but was fed up with the slow bidding - to everyones surprise he bid £100 and became the proud owner of the forge. How he explained the lack of a wardrobe and his new acqusition to his wife we do not know. Next Peter acquired some waste land where the Cafe and mine entrance now stand and with his growing collection of steam engines opened Wendron Forge to the public.
Wendron Forge 1973 - Left: the building on the left is where the Mine Entrance is today Right: the present Antiques Shop with the Cafe Car Park in the background. Right: Trenear Dairy prior to purchase.
(Photos: ©Peter Young, courtesy of Carol Young)
The 1970's was a busy period of development of the site with the Trenear Dairy and land on which the main car park is now situated.being added. With an ever growing collection of steam engines requiring larger and larger compressors to power them there were a growing number of complaints about the noise generated by the compressor. Peter decided to make a cutting in the hillside into which he intended to place the compressor to deaden the noise. Quite by chance in doing so the long forgotten workings of the Wheal Roots tin mine, described in 1856 as 'an ancient tin mine', were broken into and a new project, opening the workings to the public, was commenced.
Some of the first visitors - advertising from the late 1970's no helmets or guides in those days ! and the famous Poldark Post Box is emptied (Photo: ©Peter Young, courtesy of Carol Young)
Wendron Forge first changed its name to Halfpenny Park and later, with the transmission of the BBC Poldark series, to Poldark Mine. A number of scenes were filmed here including the underground sequences and a long relationship between the site and Winston Graham, the author of the Poldark books developed which culminated with the launch of the last Poldark book at Poldark in 2002. Sadly Winston died in 2003.
Peter Young, Poldark Heritage Site's colourful creator and Winston Graham during filming for the Poldark series -
In 1999 Poldark was placed in receivership and it appeared that an American buyer might obtain the assetts as little local interest was shown in the site. After some protracted negotiations the site and its assetts were acquired by the present owners, mining heritage enthusiasts, who formed Transcroft Limited for that purpose.
The Mine
Little is known of the early working of the mine, which was originally called Wheal Roots and worked sometime between 1720 and 1780. In 1856 it became part of the Wendron Consols Mine and is shown on the surface plan of that mine as 'old men's workings' meaning that it was at that date considered a very old mine. The origins of the mine were researched by the late authority on Cornish mining history, Dr. A. K. Hamilton Jenkin.
Because of the unusual way in which Wheal Roots Lode had been worked there is little doubt that it had been discovered by tin streamers in the bed of the River Cober and was from there mined into the hillside. This is exactly the same way that the lodes of the nearby Medlyn Moor, Basset and Grylls and Wendron Consols mines had been discovered and worked. Within the mine, but unfortunately in an area inaccessible to ordinary visitors, area tunnels which were dug without the help of explosives and where the marks of the miner's picks are still clearly visible. This indicates that some of the workings may well have been made before the introduction of explosives in the mines of Cornwall in 1689.
The mine was worked using horses and water wheels to power all the machinery and to pump water from it. In the Museum there are the remains of an early 'Rag and Chain' pump used before the days of steam to raise water from mines and which was found when the mine was rediscovered in the 1970's. The pump consisted of a series of wooden pipes made from tree trunks and through which a large endless chain was pulled. The chain had rags tied to it at intervals which when pulled up through the pipes lifted the water out of the mine.
The tin ore was pulled out of the mine through shafts using large buckets known as 'kibbles' which were raised up and down by horses driving a large drum around which a rope was attached which went down the shaft to the kibble. The drum was known as a horse whim. When underground at Horse Whim Shaft you can see the granite on the side of the shaft which has been worn smooth by the rubbing of the kibbles against it.
The miners entered the mine through shafts and had to climb down ladders carrying their tools with them. Their only means of light in the pitch black mine was candles made of tallow (animal fat). There tools were a heavy hammer and a bar with a chisel shaped end. Hitting the bar with the hammer and at the same time turning it to prevent it jamming in the rock the miners would make a hole a little under a meter in depth. Usually they made three such holes at and angle to the face of the rock. The holes would then be filled with gunpowder, a fuse made from a bird's quill filled with fine gunpowder would be put into the hole which would be sealed with clay and then the fuse lit.
Many accidents occurred as a result of the gunpowder exploding before the miners had time to reach a place of safety. Gunpowder produces a lot of smoke and fumes however the miners would return to their work as soon as the air had cleared enough to allow their candles to burn. They would remove the rock broken by the explosion and start to drill new holes.
Women and girls were never employed in the mines of Cornwall, in fact it was considered bad luck for a woman to go into a mine. However they were employed on the surface sorting and treating the ores that had been mined. Boys as young as 10 did work in the mines. Whilst we would consider this child labour today, unlike the coal mines, they usually worked with their father or uncle and were considered to be learning the art of mining.
The mineralisation at Poldark Mine can be broken down into:-
1. Early black tourmaline (schorl) veinlets. Typically millimetric in thickness these veinlets form a conjugate set trending 066°-072° and 122°. These veins are the earliest of the (hypothermal ~450°C) hydrothermal sequence, following on from purely magmatic mineralisation. They overlap in time with the development of some areas of boron metasomatism giving rise to tourmaline replacement of the granite, either side of prominent fractures (the floodlit stope with pillars is on one of these structures).
2. Blue peach veins. These structures post-date the black tourmaline veins and are characterised by the development of blue tourmaline (blue peach - a mixture of schorl and buergerite) many of these veins are small-scale features, but occasionally they form economic lodes of upwards of 0.30 m in width (Wheal Roots Lode). Like many of the black tourmaline veins (many of which are re-activated by this phase) these veinlets and lodes trend ENE-WSW (052°-072°) following the line of extensional fractures in the granite that developed along, and parallel to, the 'tough-way' joints in the host granite. This is the phase associated with the bulk of the tin mineralisation.
3. Chlorite veins. These veins mark a change in stress and temperature conditions. At Poldark they trend E-W (typical caunter lode trend) or NW-SE. They are associated with minor tourmaline and some alteration (chloritisation) of the host granite. They are not common and do not form any significant structures.
4. Chalcedony crosscourses. These late-stage low-temperature structures are common throughout the mine, typically trending NNE-SSW (around 020°) with some occasionally reactivating lodes along other orientations, or exploiting N-S and NE-SW trending fractures parallel to the 'cleaving-way' joints in the host granite. They are typically quite narrow structures (1-2 cm in width), infilled with chalcedony and haematite. The haematite appears to be at least partially (and possibly wholly) locally derived by the breakdown of biotite mica (and, elsewhere, chlorite?) in the granite, which has accompanied kaolinisation (prevalent either side of many crosscourses due to enhanced water flow). The displacement on the crosscourses (often in the range of a few cm) is largely sinistral in response to ENE-WSW shortening.
This paragenesis is typical of Carnmenellis as a whole and is repeated (with minor variations) at the South Crofty Mine, Pool.
The mineralisation at Poldark represents the roots of the lode system and the base of the tin zone, which occurs at much greater depths further north around Camborne & Redruth. At the South Crofty Mine on the 290 fathom level and below, some 1,900 feet below surface. It therefore represents a style of mineralisation that usually occurs at depth in the latest working mines in Cornwall and is the only example of this type that can still be inspected.
The mineralisation and geology at Poldark was the subject of detailed research project undertaken at the Camborne School of Mines (University of Exeter) as part of a PhD programme. The information has been supplied by:
Nick LeBoutillier BSc., PGCE., PhD., C.Geol., FGS. Consultant Mining Geologist
