Stithians to Kennall Vale

A circular walk in the valley of the River Kennall where during Victorian times the cascading river was used to power gunpowder mills, five of which exploded in a chain reaction so violent that the roof of one was found a mile away.

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The route crosses fields from Stithians to follow the Kennall valley downriver, finally reaching the entrance to the nature reserve at the bottom of the woods. The walk follows the circuit through the reserve around the remains of the gunpowder mills before continuing to Posanooth. The return route is mostly on small lanes and returns to Stithians church via the pub.

Vital statistics

  • OS Explorer: 104
  • Distance: 6 miles/9.6 km
  • Grade: Easy-moderate
  • Start from: Stithians
  • Parking: Church Road, opposite the churchyard TR37DH. Follow signs to Stithians to reach the crossroads then take the road signposted to Stithians Church.
  • Recommended footwear: walking boots; wellies after prolonged wet weather

OS maps for this walk

Click or tap on map for more info (blue=laminated)

Highlights

  • Industrial heritage of the gunpowder mills
  • Broadleaf woodland with autumn colours, fungi and spring bluebells
  • Woodland and river wildlife

Pubs on or near the route

  • The Seven Stars Inn
  • The Stag Hunt Inn

Directions

  1. Go through the gateway into the playing field opposite the churchyard and take the path to the left around the tennis courts. Follow this until it emerges on the road and continue a few paces to reach a car park for the Rugby pitch.

    It is thought that the church may be on the site of a mediaeval religious enclosure. A survey during the 19th Century recorded a circular earthwork was still present around the church and the curved side of the current churchyard may well be the remains of this.

    The oldest part of the present church building is 14th Century. The tower was added when the church was rebuilt in the 15th century. It was also extensively restored in 1870. The piscina with a carved basin is though to date from the 14th Century.

  2. Turn right into the car park and go through the gap on the right of the gate. Walk ahead along the edge of the pitch to reach a stile.

    The Romans and Greeks played games which are thought to resemble football with air-filled balls and there is a report of a Roman man being killed whilst being shaved by a barber when a ball was kicked through the window.

    A game involving running with a ball became popular at Rugby school in the 1830s and by the 1850s Rugby School football was spreading across the UK. In 1863, the Football Association was formed which formalised the rules of "soccer" (a late 19th Century Public School slang abbreviation of "association"), distinguishing it from "rugger".

    In Cornwall, the Celtic sport of hurling was already popular and may be why rugby was so enthusiastically adopted in the 19th Century.

  3. Cross the stile and head across the field to a gateway in the right-hand corner of the far hedge.
  4. Cross the stile on the right of the gate (or go through the gate if open) then cross the field diagonally to reach a stile at the bottom in the opposite corner.

    The magpie is believed to be one of the most intelligent of all animals. The area of its brain used for higher cognitive function is approximately the same in its relative size as in chimpanzees and humans. Magpies can count, imitate human voices and have been observed regularly using tools to keep their cages clean. In the wild, they form gangs and use complex social strategies for hunting and tackling predators. It has even been suggested that magpies may feel complex emotions, including grief.

  5. Cross the stile and follow the path over a bridge to a junction.

    According to folklore, it's unlucky to bring bluebells into a house and also unlucky to walk through bluebells as it was thought that the little bells would ring and summon fairies and goblins.

  6. Turn right and follow the path over the wooden footbridge and stone stile until it emerges beside some buildings and continue to reach the road.

    The streams on the route are all tributaries of the River Kennall which joins the Carnon River at the head of Restronguet Creek opposite Devoran.

  7. Turn left onto the road and cross the bridge. Continue a short distance further on the road to reach a stone stile on the right marked with a Public Footpath sign, just before the National speed limit signs.

    A foundry, later known as the Hammer Mills, was in existence before 1811 and was last recorded working in 1889. The hammer in question is likely to have been a trip hammer (a metal weight raised by a waterwheel and then dropped under gravity) used to beat the softened metal into shape. The foundry manufactured (Cornish) shovels.

  8. Cross the stile on the right and go through the metal gate. Follow the left hedge of the field across the field to reach a stile in the far hedge.

    If there are sheep in the field and you have a dog, make sure it's securely on its lead (sheep are prone to panic and injuring themselves even if a dog is just being inquisitive). If the sheep start bleating, this means they are scared and they are liable to panic.

    If there are pregnant sheep in the field, be particularly sensitive as a scare can cause a miscarriage. If there are sheep in the field with lambs, avoid approaching them closely, making loud noises or walking between a lamb and its mother, as you may provoke the mother to defend her young.

    Sheep may look cute but if provoked they can cause serious injury (hence the verb "to ram"). Generally, the best plan is to walk quietly along the hedges and they will move away or ignore you.

  9. Cross the stile and turn right onto the lane. Follow it down to the bottom of the valley and across the bridge. Continue on the lane from the bridge to the top of the hill to reach a stile beside a gateway on the left, marked with a Public Footpath sign.

    The majority of buzzards diet is earthworms and carrion and consequently they have a reputation for being lazy and scavengers. However, when they need to be, buzzards are formidable predators. Diving on rabbits and small mammals from a slow or hovering flight, or from a perch, they nearly always make the kill on the ground.

  10. Cross the stile and follow the right hedge to a gateway and stile topped with a piece of iron.

    The Kennal Vale gunpowder mills were located in the woodland on the left at the bottom of the valley. The walk will take you down there shortly...

    Gunpowder was discovered by accident by Chinese Alchemists attempting to make an elixir of life to render themselves immortal. A text from the 9th Century documented the event which quite literally backfired:

    smoke and flames result, so that their hands and faces have been burnt, and even the whole house where they were working burned down.
  11. Cross the stile (or go through the gate if open) and follow the right hedge to a gate and stone stile.

    German miners (whose traditional outfits now appear on garden gnomes) introduced the use of gunpowder for mine blasting in Cornwall in 1689 (as well as gnomes). This was first carried out in one of the mines of the Godolphin estate, quite possibly Great Work Mine.

    Gunpowder represented a great technological breakthrough, as beforehand, rocks had to be cracked by heating and rapid cooling, or by soaking wooden wedges in water. An amount of granite that would take 6 days of work to break with a pick could be broken in one blast.

  12. Cross the stile and follow the right hedge past the buildings to reach a metal pedestrian gate surrounded by granite gateposts.

    Gunpowder was imported into Cornwall until 1808 when the first Cornish gunpowder factory opened at Cosawes Wood, Perranarworthal, about 5 miles from Falmouth, followed by another at nearby Kennall Vale in 1813. By 1836, the consumption of this was considerable with 30 tonnes being used in Cornish mines. By the 1860s the three largest mills were in Kennall Vale, Herodsfoot and the infamous Trago Mills.

    Secluded river valleys were chosen as the sites for gunpowder mills for their distance from population, shielding provided by trees and the availability of water power. In the event of an explosion, the trees also shielded the process buildings and storage magazines from one another, reducing the chance of a chain reaction. The roofs of the buildings were also designed to blow off relatively easily so the force from the explosion (and any fragments of occupants) would be vented upwards, minimising the damage to the building.

  13. Go through the gate and walk down to the lane. Turn left and follow the lane downhill until you reach the entrance to Kennall Vale on the left, where the stone wall ends and roughly 50 metres before the 30mph signs.

    The reason that mills were required for gunpowder manufacture is that the finer the particles of the three ingredients, the more explosive the mixture. An ultra-fine dry dust would be far too dangerous both to manufacture or use so the ingredients were ground down into a fine paste using water. The paste was then broken into granules before being dried out. Any dust was removed from the granules as it would have been disastrous to have suspended particles of gunpowder within the air of a mine where metal tools and candles were being used. Finally, the dried granules were coated in graphite to make them flow more easily and also more water-resistant.

  14. Turn left into Kennall Vale Nature Reserve. Follow the gravel path to a gate and pass this. Continue to where the path forks in front of a stone building.

    The Kennall Vale gunpowder factory was immediately successful and by 1819 it was thriving: "Here are situated waterwheels constantly employed, two of which keep 14 tons of marble constantly turning (three tons and a half in a block), making four to five thousand barrels of gunpowder annually; some of the mills have occasionally blown up, but no life has been lost; it employs a fine fall of water of eighty four feet".

    The Kennall Vale Company continued to expand, eventually taking over the rival works at Cosawes Wood. By 1860, the company was employing about 50 men. When high explosives came onto the market in the 1880s, the factory declined and closed in the first decade of the 20th century.

  15. Continue ahead past a stone building on the left and 3 concrete buildings on the right to where a small path departs to the left just after the group of buildings.

    Each stage of the multi-step process of gunpowder production was carried out in a different building. Each of the buildings dotted around the valley had a very specific role.

    The first stone building on the left just after the fork in the path was the packing house where wooden casks were filled with the finished product.

  16. Continue ahead past one more building to reach a fork in the path at the far side of the quarry.

    The path to the left leads to an area overlooking the quarry pit.

    The granite quarry was opened in the early 20th Century and the concrete buildings nearby are from this period (whereas the Victorian buildings for the manufacture of gunpowder are built from stone).

  17. At the fork, bear right and then left to the footbridge across the river.

    The building ahead in front of the wall was the Corning House where fragments of gunpowder "cake" were sieved into standard sizes using parchment meshes. The word "corning" was used as a synonym for "granulating".

    The high brick wall behind this is a blast wall designed to contain any explosions.

    The stone foundations of small building part-way up the valley to the left was where gunpowder granules were graded and dust was removed. It is thought that the main part of the building was built from wood.

    Several small buildings dotted around the site were powder magazines for storing gunpowder. There were strict limits on how much gunpowder could be held within the main processing buildings so any extra was spread across these. These included the building to the right before the river and one higher up the valley to the left behind the dusting house.

    The elevated structure that looks like it once spanned the river is the remains of a bridge. The building on the opposite side of the river from this was the glazing mill where the finished granules of gunpowder were rounded off and coated in graphite.

  18. Cross the bridge and bear right behind the buildings. Follow the path to a flight of granite steps after the last building. Descend these and keep following the path across footbridges and behind more buildings until it eventually emerges on a track beside a stone bridge over the river.

    The tall buildings along the river were known as incorporating mills where the powdered ingredients were combined with water and ground into a paste of fine particles. The amount of water had to be carefully regulated as too much would wash away the soluble saltpetre and too little would leave a dry powder which would likely result in an explosion. This part of the process was the most dangerous and the reason there were so many incorporating mills is that the amount of gunpowder in each was strictly limited to reduce the size of explosions. The thick stone walls contrasted a light roof which was designed to allow the force of an explosion to be vented upwards.

    The building just before the final junction was the change house where workers put on special woollen suits designed to avoid creating sparks.

  19. Turn right and cross the bridge then follow the track uphill to where a path departs to the left to cross over a small stream.

    The building beside junction with the track was the mixing house where the ingredients were combined before being transferred to the incorporating mills.

  20. Turn left onto the path crossing the stream and follow the path up the steps to emerge onto the main track leading into the reserve.

    The small stream is actually a leat that pre-dates the gunpowder mills and was used to carry water though Ponsanooth to power the mills there. Look out for the mill-related names of buildings as you pass through Ponsanooth later on the walk.

  21. Turn left to retrace your steps out of the Nature Reserve and reach the road.

    As you make your way out of the reserve, you can trace the leat running below the track. The stream running beneath the track was also used to top up the leat. A metal sluice controls the amount of water retained in the leat and released into the stream below.

  22. Turn left onto the road and follow it downhill until you reach a junction on the right beside the "No Footway" sign.

    Kennall House was built some time before 1840 for the manager of the gunpowder works and is sheltered behind a natural rock outcrop from any explosions that occurred in the works. This area is now private property and includes some other remains of the gunpowder works. Outbuildings that have been converted include a foreman's office and a cooperage to make the barrels that the gunpowder was packed into. A large chimney also remains from the drying house where the tiny clumps of wet gunpowder paste dried out and hardened into granules.

  23. Turn right onto the residential road. Follow it to a bend where a stony track departs to the left past a garage.

    The first recorded fatality at the mills was in 1826 when an old woman brought a basket of roast potatoes for the men working in the mixing house. A spark ignited the gunpowder mix and both the woman and one of the men were killed.

  24. Join the stony track ahead and follow it to where it forks just after Carrick Millhouse.

    In May 1838 the spacing of the incorporating mills was found to be inadequate when there was a major series of explosions in which one man was seriously injured and another killed. A newspaper reported: "Five mills blew up in succession, and part of a roof was found a mile from the premises. The reports were most terrific and created the greatest alarm over an extensive tract of country". Future explosives works such as the National Explosives Works in Upton Towans were subsequently designed to avoid chain reactions such as this by isolating each building in a sand bunker within the dunes.

  25. Keep right at the fork and follow the track until it ends on a tarmacked lane beside 3 Millstream Cottage.

    The West Briton in 1841 records that John Martin "was seen to go into the glossing mill to bring out some more powder, and presently afterwards the mill was blown up in the air with a tremendous explosion which was heard many miles around, and shook the houses a considerable distance off… The head of the deceased was discovered about a quarter of a mile from the spot, and other parts of his body were afterwards collected from different places."

  26. Turn right and walk uphill past the chapel to reach a junction on the left opposite a telegraph pole.

    The massive gain in efficiency by breaking rocks with explosives rather than hand tools resulted in increased profits for the mine owners but it was less good for the miners themselves. When gunpowder burns, it produces copious amounts of acidic sulphurous gasses which attack the respiratory system - far from ideal in the poorly-ventilated confined space of a mine. A quill or reed filled with gunpowder was used as a fuse which worked most of the time but burnt at an unpredictable rate, and burning material from the fuse could drop and prematurely ignite the main body of gunpowder. Consequently there were many horrific accidents and fatalities.

  27. At the junction, turn left and follow the terrace until it ends in a junction.

    In 1830, William Bickford devised a way of making blasting safer, based on his observations of the activities of a rope maker. His safety fuse consisted of a core of gunpowder surrounded by twisted yarns, bound in twine and sealed with tar to make it waterproof. Since gunpowder contains everything it needs to burn without the need for oxygen from the air, it would burn reliably inside its waterproof container at a predictable rate of 30 seconds per foot.

  28. Continue ahead to reach the main road then turn right onto this and follow it uphill to the National Speed Limit signs. Continue until you reach a junction to the right signposted Stithians 2½.

    During winter, from November to March, winter heliotrope is visible along the edges of roads and paths as carpets of rounded heart-shaped leaves. The name is Greek for "sun direction" because the flowers turn to follow the winter sun.

    Winter heliotrope produces spikes with pale pink scented flowers in December and January. The scent resembles marzipan i.e. almond and vanilla.

    The leaf shape is similar to its close relative butterbur, but the leaf edges are more rounded than butterbur and the leaves are evergreen whereas butterbur puts up flowers before it has any leaves. Both plants spread via rhizomes (underground stems) and their broad leaves can crowd out other plants making them potentially invasive.

  29. Turn right and follow the lane until you reach a junction to the right signposted Stithians 1¾.
  30. Turn right and follow the lane until you reach a pair of public footpath signs beside some gateways on the left where the lane bends sharply.
  31. Go through the gateway ahead marked with a Public Footpath sign and cross the field to the gateway opposite.

    The number of cows in Cornwall has been estimated at around 75,000 so there's a good chance of encountering some in grassy fields. If you are crossing fields in which there are cows:

    • Avoid splitting the herd as cows are more relaxed if they feel protected by the rest of the herd. Generally the best plan is to walk along the hedges.
    • Do not show any threatening behaviour towards calves (approaching them closely to take photos, making loud noises or walking between a calf and its mother) as you may provoke the mother to defend her young.
    • If cows approach you, they often do so out of curiosity and in the hope of food - it may seem an aggressive invasion of your space but that's mainly because cows don't have manners. Do not run away as this will encourage them to chase you. Stand your ground and stretch out your arms to increase your size. Usually if you calmly approach them, they will back off. It's also best to avoid making sudden movements that might cause them to panic.
    • Where possible, avoid taking dogs into fields with cows, particularly with calves. If cows charge, release the dog from its lead as the dog will outrun the cows and the cows will generally chase the dog rather than you.
  32. Go through the gateway and continue ahead to a stone stile in the right hedge roughly halfway between the two tall trees and the corner with the far hedge.
  33. Cross the stile and follow the left hedge to reach a track just before the gates opposite.
  34. Turn left onto the track and follow it where it splits just after Tory Farm.

    The Tremenhere longstone is nearly 10ft tall and thought to date from the Bronze Age. There is an iron peg in the stone which is somewhat more recent. Being located fairly close to the farm house, this was a handy spot to attach the other end of a washing line! The name Tremenhere was first recorded in 1297 and means "longstone farm".

  35. Keep left at Tory Farm to reach the driveway for Lakeview Cottage. Pass the driveway and continue on the track to where a path departs ahead.
  36. Follow the path until it ends on a lane.

    Celandine flowers close each night and open each morning. This is controlled by a circadian rhythm, so they really are 'going to sleep' at night and 'waking up in the morning'. It is likely that this has arisen to protect the internals of the flowers from any frost during the night as they begin flowering in March when frosts are still common.

  37. Turn right onto the lane and follow it for roughly half a mile until you reach the crossroads in Stithians.

    When you reach Velandrucia Bridge at the bottom of the valley before Stithians, the road crosses over two streams. The second is the River Kennall and the first was a mill leat for Tregonning Mill situated further upstream. The first part of name "Vellandruicia" is probably derived from the Cornish for "the mill" an velyn.

  38. Continue ahead at the crossroads on the road signposted for the church to pass the pub and complete the circular route.

    The first record of the settlement of Stithians is from 1268. The name is thought to derive from the name of the female saint to whom the church is dedicated.

Help us with this walk

You can help us to keep this walk as accurate as it possibly can be for others by spotting and feeding back any changes affecting the directions. We'd be very grateful if could you look out for the following:

  • Any stiles, gates or waymark posts referenced in the directions which are no longer there
  • Any stiles referenced in the directions that have been replaced with gates, or vice-versa

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