18th Century Seaton Delaval Coal Mines

Aerial photos of the the undeveloped land surrounding Seaton Delaval and Hartley show cropmarks and small plantations which indicate the sites of 18th century coal pits and wagonways. The mining activities often damaged the surface and crops, or even meadow, would no longer grow at these places. There are dozens of identifiable sites although there were over 40 recorded pits in the area. These were generally of a short duration of five to ten years.

Location of some of the identifiable collieries in the Hartley district

There had been earlier, primitive, shallow bell pits further South in the Cullercoats and Whitley area which supplied coals to local salt pans, but were in decline by 1710 and the pans were sold off. The pier, which had been constructed at Cullercoats for shipping was also in need of constant attention.

Newcomen's steam, or fire engine as it was often termed, had come into general use in the Newcastle district in the 1720s. It allowed for greater depths of mines. And in the second half of the 18th century was vastly improved, with the use of cast iron in the construction, and became more powerful and larger allowing the coal North of the Briardene geological fault to be got at.

Land surrounding collieries topped with slag and coal dust. Not ideal growing conditions?

Northumberland County History: Tynemouthshire

"At this point attention may be directed to the northern portion of the district, in which there are records of coal mines about Hartley so far back as 1291. These were doubtless small outcrop pits worked for local supply, one being held by the prior and convent of Brinkburn at the time of the dissolution, and afterwards leased by the Crown to Sir Ralph Delaval in 1596. Before this time salt pans had been established at Hartley and their produce shipped at Blyth, the coal trade continuing to be a purely local one. Sir Ralph leased his mines in 1611 to Sir William Slingsby, and in 1619 to his own sons, but at the time of his death in 1628 they do not seem to have been of much account and are described as yielding no benefit to the owner.

Apparently there was little change until the latter half of the century, when Sir Ralph Delaval, the first baronet and grandson of the above mentioned Sir Ralph Delaval, took in hand the development of his property. He built a pier at Hartley Pans, or Seaton Sluice, as it was afterwards called from his having scoured the harbour by a device controlled by a sluice, and through the improvement of the harbour secured a coasting trade for the produce of his collieries and salt pans. Under his guidance and as the result of his energy the trade expanded, in spite of the fact that the Hartley coal was not so well suited for the needs of the coasting trade as that of the Tyne district. Its uses at that time may be best described in Sir Ralph's own words: the smallest will serve for lime burning and the rounder will please the cook because they make a quick fire and a constant heat.

The pits at this period were situated near the coast, to the south of Seaton Sluice, where the High Main, Yard, and Low Main seams lie at shallow depths as they rise towards the sea, and their development was attended with some difficulty, owing to the heavy feeders of water which occasionally overcame the rag and chain pumps then in use.

Sir Ralph Delaval was succeeded by his son, Sir John Delaval, and the mines were leased by him to John Rogers, one of the lessees of Whitley colliery, who with his son worked them up to 1725, when they were taken over and carried on by Sir John until his death in 1729. His successors continued to work them without any change of moment until the middle of the eighteenth century, when Sir John Hussey Delaval (afterwards Lord Delaval) became the owner of the estate and embarked on a career of enterprise of which his younger brother, Thomas Delaval, was subsequently the guiding spirit.

Glass and copperas works were established in order to utilize the small coal and brasses, or iron pyrites, from the pits, and in 1758 a fresh winning to the dip was commenced. This was followed in 1764 by the opening of the new entrance to the harbour of Seaton Sluice, cut through the solid rock to the east of the old approach, and looked upon as one of the greatest engineering feats of the day. The harbour improvements brought more trade for the pits, which in 1770 employed 300 hands, and six years later sent nearly 48,000 tons of coal away coastwise, principally to the London market, where, we are told, the Hartley coal was much esteemed by bakers.

Thomas Delaval, who was humorously described by a friend as being  busy as a bee flying from flower to flower, extracting coals from the bowels of the earth, and bottles out of damnation fiery furnaces, was equally energetic in his direction of the collieries. A new 'fire engine,' designed bv William Brown, at that time the great authority on pumping engines in the district, was set to work in 1760, and in 1763 a steam winding engine, the invention of Joseph Oxley of Ford, was erected and regarded as the greatest improvement since the introduction of the pumping engine. At this time the problem of raising coals from the deeper seams, by some quicker and more economical method than the existing horse gins, was attracting attention, and Oxley made a determined attempt to solve it.

A second engine, put down at Hartley in 1765, appears to have attracted a great deal of attention, drawing coals 'by fire' at the rate of a corf a minute for some years. It is evident, however, that it had its defects, and James Watt, who visited Hartley about 1768, described the engine as going sluggishly and irregularly, having no flywheel.

Another mechanical curiosity was a boiler built of stone and used in connection with both the winding and pumping engines. It is represented as being capable of effecting a saving of £300 a year, but most probably it did not stand the test of constant use, and, like Oxley's winding engine, was superseded by appliances of a less 'advanced' description. The double water wheel, with a pumping engine for the circulation of the water, came rapidly into favour in the district for drawing coal, and it was not until the end of the century that, through Watt's improvements, a reliable steam winding machine was produced and drove the water wheels into oblivion.

By 1780 the workings in the Yard and Low Main seams had advanced southwards to the Brierdean dyke, and as far to the dip as the level of the Engine pit. In this year the coal beyond the dyke had been opened out, and the wagonway, which can still be traced connecting the pits with Seaton Sluice, was extended southwards to the Brier Dean. After this the field lying to the west of the burn and to the dip of the old pits was entered upon, and before 1799 the Chatham and Nightingale shafts had been sunk and connected with the harbour by a branch line crossing the dean on a wooden viaduct.

Nightingale Colliery Shaft

Nightingale Shaft:
High Main Seam 90 feet
Coal 156 feet 1' 8" thick
Yard Seam 273 feet 3' 6" thick

The days of the direct control of the Delavals were now nearly at an end. Lord Delaval died in 1808. His brother and successor, Edward Hussey Delaval, continued to reside in London, and seems to have let the mines before he died in 1814.

Until towards the close of the eighteenth century, the system of working practised consisted in the removal of a portion of the coal only, the remainder being left for support. The shafts, which had originally been only a few yards apart, were gradually extended to wider distances and worked larger areas as they reached greater depths. The small pillars left were then subject to 'creeps,' caused by the crushing down of the overlying strata, more especially when, as time went on, efforts were made to minimize the loss of coal by working out portions of the pillars, a common practice before the system of leaving larger pillars and afterwards removing them entirely had been introduced."