Hebden Horse Level

Hebden Horse Level is a trial level close to the centre of the village, driven in an attempt to intercept lead veins close to Grimwith Reservoir. It was unsuccessful. Since that time it has been designated as a World War II air raid shelter, a Cold War bunker, and been used by the fish farm. This page is an attempt to tell its story. Most of the features described many be seen in photographs available here.

Historical Background

The veins that underlay the area around Yarnbury had been exploited since the early eighteenth century, and had proved to be very productive over a long period as technology improved. These veins extend into Bolton Gill, which was part of the Hebden Liberty, and although there had been sporadic attempts to extract the lead the broken nature of the ground discouraged the early miners. However, in August 1853 William Winn of Harrogate and Joseph Osborne of Leeds formed a partnership and were granted a lease for mineral extraction in Hebden, initially for three years, but with an option to renew. They extended their partnership to include George Crossland, a merchant from Huddersfield; William Shaw, a wool merchant also from Huddersfield; and George Cook from London and Joseph Thomas from Liverpool (later of St. Albans in Hertfordshire), who were joint partners in a London wool broking company. These were all men successful in their own fields who wished to cash in on the opportunities offered by the Yorkshire lead mining industry. The partnership was dissolved in November 1854, and the Hebden Moor Mining Company established as a Cost Book Company, with the six partners being the first directors. In August 1855 a further £500 was raised from the shareholders.

Initial investigations must have been promising, for in August 1856 the lease was renewed for a further twenty one years and assigned to the company. Winn and Osborne were each given 10,000 £1 shares as payment for their interests. Winn had sold his share by 1857, and Osborne his by 1862.

The main centre of activity was in Bolton Gill itself. Initially Top Level was driven at an altitude of about 300 m, and a dressing floor laid out at the portal. Bottle Level was then driven in at the level of the valley floor, and Bolton Gill Engine Shaft sunk to aid pumping and servicing. In the end there were three interconnected levels that extended into the hillside for about a kilometre.

A road was driven up Hebden Gill including the still-standing Miners' Bridge; a large dressing floor was built close to the entrance of Bottle Level; two reservoirs and associated leats were constructed on the moor; and a small smelt mill built further down Hebden Gill adjacent to Hole Bottom.

During the first few years, the enterprise was successful, with production ramping up steadily to almost 300 tons in 1862.

Unfortunately, the Bearing Grit which contained the productive veins dipped to the east, and eventually they dropped below the entrance of Bottle Level which was used to drain the mine. Three years later the production was down to under 36 tons, and thereafter never produced more than a relative trickle. No ore extraction was declared after 1872, so it can be assumed that operations had ceased by then. Steel cables used as a power rope up Hebden Gill were sold to William Bell, the local blacksmith, to be used in the construction of a suspension bridge over the River Wharfe where they may still be seen today.

In 1873 in one final effort to retrieve their fortunes, the company began to drive a level from the village of Hebden, some 90 m lower in altitude than Bottle Level. This was intended to intercept the veins far to the east, hence opening up a vast new area. This was a bold enterprise, as they would knew that they needed to drive the level for two and a half kilometres before getting any return. In 1877 a further 21 year lease on the mineral rights was taken.

However, the Beevor and Cockbur veins were found to be barren of ore when they were finally reached in June 1888, and the venture was abandoned. Hebden Moor Mining Company commenced liquidation proceedings in March of the following year, and by June James W. Close, the appointed liquidator, was advertising the plant in the July 13th 1889 edition of the Mining Journal:

"For Sale: 8 feet waterwheel, 20" broad, iron boss, shield and buckets, wood arms and lining, wrought iron axle, two pedestals. About 1 ton of 6" zinc piping. One 26 feet waterwheel, 4 feet broad, cast iron axle, iron bosses, wood arms, bottoms and buckets, iron shields. 2 sets of rollers for crushing lead ores, 4 rollers in each set, one set of second rollers, for crushing lead ores, and gearing complete. One 40 feet diameter waterwheel, 3 feet 6 inches broad, with iron axle, bosses, shields, bucket and bottom, 16 wood arms, 16 wrought iron diagonal arms, 12 feet driving wheel, jack wheel, 3 feet beam, 4 inch shaft and pedestals. One Ingersoll Rock Drill, nearly new with adjusting rest. One lead ore smelting hearth."

The Location of the Entrance

The entrance to the level is situated some 300 metres below the bridge where the B6265 crosses Hebden Beck, on top of a large platform of spoil known locally as Smithy Hill. It lies at an altitude of 181 m, with a grid reference of SE 02842 62966. Next to it are the remains of a mine building, which is thought to have originally been a stable to house the ponies. It used to have a hay loft. Alongside that was a second building which was probably the main mine building. This was later taken over by William Bell, the village blacksmith, who used it as his smithy. It was demolished in the 1950s, and there are few traces of it now.

The lowest pin marks the entrance; the next to the north-east marks the limit of the currently accessible section; and the third marks the location of the Copper Gill Air Shaft.

The Construction

The level was started at an altitude of 181 m, about 10 m above the floor of Hebden Gill. This allowed the spoil to be directly trucked out of the level and tipped down the bank. A railway line with a 19" guage was laid into the level, and the spoil from the face loaded into wagons and removed by horse. The spoil heap is now known as Smithy Hill, as the village blacksmith later used the main mine building (now gone) as his smithy.

A piece of the old track may be found half-buried in the bank above the entrance. Much of the track is still in situ in the level, but is usually buried under silt. In places, track was also used as a footing for the lining wall.

Compressed air drills were used to speed up the digging. These were originally patented by Joseph Fowle in the United States in 1851, and were at least five times faster than drilling by hand. In addition, the exhaust air aided ventilation, albeit at the cost of increased dust, and requiring considerable capital investment. The air compressor was powered by a 26' diameter waterwheel - the remains of the pit may still be seen below Smithy Hill. In the level itself, 30 cm long iron brackets hammered into the south-east wall were used to support the air hose. The air supply was probably carried in lengths of canvas hose, connected by brass fittings. The size of the brackets indicate that the hose was probably two inches in diameter.

1¼" shot holes to a depth of 18" were drilled, and 4" long dynamite cartridges inserted. A percussion cap was placed over the cartridge, and tamped with mud, and this was fired using a slow-burning fuse. Dynamite was patented in 1867 by Alfred Nobel, which together with the use of compressed air drills, indicates that the latest technology was being employed.

In general, the level was intended to be seven feet high and six feet wide, but it varied according to the stability of the ground.

The level passes through the North Craven Fault, and much of the first 200 metres or so is lined, presumably because it passes through unstable ground. Most of the rest of the currently accessible level is in pretty stable rock, although there are areas of slabby mudstones which are propped with timber, and the last fifty metres are positively unstable.

In 1881 there were eleven underground staff employed by the company. If, as is maintained by the contemporary account, there were three shifts this indicates about four people on a team. The same account suggests that two of these would be working at the forehead, implying a couple disposing of the spoil and carrying out other necessary operations.

Because of the distances involved, it became necessary to improve the ventilation, and an air shaft was dug above Copper Gill on the far side of Backstone Edge Lane at SE 03571 63733. Few signs of it now remain. It is thought that an 8' compressor wheel was installed upstream of the air shaft to force air through pipes to the forehead to improve ventilation. Whether this was used to boost the compression of air arriving from the portal to allow the compressed air drills to ventilate the forehead, or whether compressed air drilling was abandoned, and the wheel used to force air to the forehead just for ventilation is unknown.

The Water Supply and Power

To speed up excavation in Hebden Horse Level, the Hebden Mining Company employed compressed air drills which were powered by a 26-foot diameter waterwheel. Unfortunately, this impressive structure was dismantled some time between about 1905 and 1925, and the only obvious remnant is what remains of the back wall of the wheelpit below Smithy Hill.

Inspection of the available photographs indicate that the framework of the waterwheel was made of wood, and that it began life as a breastshot wheel with a supporting frame of 12 sets of arms, and a 3 foot six inch face with 108 buckets, but was later converted to an overshot wheel.

It was originally powered using water extracted from the small beck running down the bank to the north. The water was channelled along a leat following the contours of the hill, to a storage pond built at the back of Smithy Hill, and then fed through an underground conduit to a small wooden flume. The remains of this small structure may be seen in the early postcards of the waterwheel as shown on the left.

This set-up couldn't have been very efficient as the water entered the wheel at about nine o'clock. Later, however, a more reliable source of water was tapped when the level broke through into what was probably the Middle Limestone of the Yoredale Series, and intercepted an underground stream. The water drained out of the entrance, and it was then carried across to the top of the waterwheel in an impressive wooden flume to feed the wheel at about 11 o'clock - hence almost doubling the head.

One report has it that the flume was some 60 cm wide, and water flowed to a depth of some 30 cm "enough to drive the wheel and never varying". The remains of the flume and its supports may be clearly seen in the photographs taken around 1900.

Much of the line of the underground tailrace from the wheel pit has been buried under the spoil from the level, but it follows a direct line from the wheel pit for 60 m, and emerges about 10 metres from Hebden Beck from a small stone-lined conduit.

Underground Today

Many walkers walk within 50 metres of the entrance of Hebden Horse Level along the footpath down Hebden Gill between the village and the bottom of Mill Lane, without being aware of its existence. Its entrance is on the other side of the beck at the top of the spoil heap, locally known as "Smithy Hill", tucked behind the ruins of the remaining mine building and protected by a substantial padlocked iron gate. The level is currently accessible to properly equipped and experienced mine explorers for about 400 metres, but the hazards include deep water, an unstable roof, rotting wall props, and bad air. In general, the level was intended to be seven feet high and six feet wide, but it varies according to the stability of the ground.

From the entrance the first 80 metres or so is actually in very good condition, with neatly stone-lined walls and roof, and a smooth floor. During the Second World War, the level was used as the village air raid shelter, with duckboards placed over the stream for the first 20 metres. It was never used in anger, but locals remember as kids having to retreat there during air raid practices. During the Cold War it was designated as the local Civil Defence Shelter, but fortunately its efficacy was never tested.

The level has always had a plentiful stream running through it, and in the 1980's the local fish farm took advantage of this ready source of water by installing a salmon hatchery. To ensure a constant supply, a 2 metre high wall was built about 85 m in, creating a reservoir behind it some 150 m long. The hatchery was superseded after about ten years, and the dam's outlet pipe was lowered in 2003 to aid exploration. Various plastic pipes, breeze-block supports and the dam itself are all that remain today.

The dam is a substantial structure, built in a small chamber where the roof lining gives out. It is necessary to clamber over the wall, and drop down the other side. This used to have a water depth of 1½ metres, gradually shallowing over the next 150 m, but is now no more than ankle-deep. The original depth can be seen as discolouration on the walls.

For the next 240 m the going is relatively easy with the walls sometimes lined and sometimes not. At one point, a small alcove has been built into the wall on the left. The rail tracks can sometimes be distinguished embedded in the muddy floor, and supports for a compressed air pipe adorn the right hand wall.

It has been noted that the level was only accessible for 317 m in 1942, and this was the limit until 2003. At that point, a steeply dipping thick bed of a white powdery material, thought to be fault gouge, had slipped from the roof, and blocked the passage, damming the water behind it to the roof. In 2003 a channel was dug through this obstruction for about 10 m, lowering the water level beyond by a metre and a half. This allowed access to a further 50 metres of passage, which requires wading through chest-deep water and a deep silt floor which had accumulated behind the obstruction, to a similar obstacle. This too was dug through, and a further semi-flooded section with a very slabby, unstable roof entered. A collapse at the end of this can be crawled through, leading to a ponded section where the silt and water reached the roof. This is about 400 m from the entrance, and further progress could only be gained with considerable effort.

The air is of poor quality from the first collapse onwards.