Saltom Pit 1731
Coal has been mined in Britain since at least the Roman period, although the scale of workings was very small until the mid-16th century. Up to that date, coal was extracted largely from outcrops – places where the coal seams appeared on the surface. Sometimes the seams were followed vertically downwards, which resulted in ‘bell-pits’ – shafts that bell out at the base to exploit a small area of the seam.
Coal output in England increased considerably from the second half of the 16th century, largely as a result of a growing shortage in the national stock of wood. Coal was increasingly being used in the home, but new technological developments were also creating more uses for coal as an industrial fuel. The development of coal-fuelled glassmaking in the early 17th century, the introduction of reverberatory smelting of non-ferrous metals in the late 17th century, limeburning, saltmaking, the preparation of alum, and the use of coke-fuelled iron furnaces in the 18th century all stimulated the demand for coal.
These developments created an increasing cycle of consumption. The growing industrial demand meant that miners needed to tap larger and, more importantly, deeper seams. One of the great problems facing miners was the flooding that was encountered at great depths. A solution to this was provided by the invention of the steam engine, which was used to pump water from the mines. However, the steam engine was rapidly adapted to serve other industries, and by the late 18th century, for instance, it was being employed to drive the new textile mills. This in turn greatly increased the demand for more coal.
New methods of coal mining had to be introduced to satisfy this ever-increasing demand for the ‘black gold’. During the 18th century Cumberland and Tyneside emerged as important coal mining areas, where new techniques were developed.
Coal mining was certainly the earliest industry to have a major effect on the economy and landscape of West Cumberland. The coalfield within the region is small, the most important section extending in length some 14 miles from Whitehaven to Maryport with a breadth of some 4-6 miles from the coast inland. This coastal position was to be a great advantage, as sea transport could be used for longer distance trade. The Irish market was particularly important, as Ireland produced no coal itself. During the early 18th century, coal from Sir James Lowther’s mines near Whitehaven was the most common in Dublin, but during the 1720s an increased share was being supplied from his competitor’s mines in the Workington area. Lowther saw this as a major threat to his business, and in order to maintain his share of the market he wanted to increase production from his pits. His choices were mining deeper, or further inland. Lowther chose a combination of the two, by proposing mining to a lower level, and winning coal from under the sea.
The main problem facing Lowther in achieving these ambitions was technology. He sent his steward of the estate, Carlisle Spedding, to Newcastle, to learn about the improvements in coal mining being developed there. Spedding gained work as a hewer in several collieries under a fictitious name, until he was burnt in an explosion and his true identity was revealed. After his return in the 1720s, Spedding sunk an exploratory bore at Saltom, on the Cumbrian coast near Whitehaven, and found the Main Band at a depth of 80 fathoms. He proposed to sink a pit just above the high-water mark and erect a powerful pumping engine, ‘which would drain hundreds of acres under the land, and an unknown, but enormous extent under the sea’. Work began in 1729, and by 1731 the pit had reached a depth of 456ft.
The sinking of Saltom Pit was a huge undertaking, described by Spedding himself as ‘perhaps the boldest thing that was ever undertaken’. It represented the first attempt at undersea mining in England, and was the deepest undersea mine ever, at that time.
A major problem with deep mines was the very real risk of underground gases exploding, particularly methane or ‘firedamp’. Although firedamp had been encountered in earlier shallow workings, the sinking of Saltom Pit brought the miners sharply into contact with its dangers. When the shaft had reached a depth of 252ft, a large pocket of firedamp was encountered. Like a true entrepreneur, Spedding’s response was to have the gas piped to the top of the pit and offered for sale for the illumination of Whitehaven! More importantly, he experimented with the gas and its characteristics, and shortly afterwards invented the ‘Steel Mill’ lighting device (a forerunner of the celebrated Davy Lamp). Essentially, this was a piece of flint that was pressed against a small wheel, and produced a shower of sparks when the wheel was rotated. Spedding had discovered that momentary sparks were less likely to ignite firedamp than the flame given off from the only alternative lighting system of the time – candles.
The most effective way of protecting against explosions, however, was an adequate system of ventilation. The problem of ventilation was especially significant at Saltom; not only was there a greater amount of firedamp at this depth, but also the traditional practice of a separate upcast flue could not be used under the sea. In order to solve the problem, Spedding split the shaft into two with timber boarding and designed a system of ‘coursing the air’ to allow the passage of air throughout the workings. It worked by a system of boarding and doorways (usually operated by boys) which forced an air-current to sweep through every part of the mine between its entrance at the downcast and its exit at the upcast pit. The oval-shaped shaft, which was introduced by Spedding at Saltom Pit, made this much more effective.