Introduction
The coalworks of Duddingston, Niddry, Edmonston and Woolmet were at one time all connected by a tunnel or "level" beginning from the sea shore at Joppa and running underground for 3 miles. The tunnel allowed water to drain away from coalworking, without the need for pumping engines or other mechanical devices. To drain the maximum amount of coal, it needed to be cut at the lowest depth possible.
The man responsible for construction of the sea level was John Biggar of Woolmet. He started it in 1745 when he leased the coal at Duddingston, and then Niddry in 1748 allowing hom to extend the level through these estates towards his own coal at Woolmet. It was very successful for a time but by the end of the century most of these coalworking were abandoned due to flooding.
Before the Level
The coalworkings on the Duddingston and Niddry estates (and probably the edge seams at Edmonston and Woolmet too) had been drained by a method known as 'chains and buckets' - a continuous chain with buckets attached to lift the water. Horse powered gins would provide the power for to lift the buckets; at Niddry, five horses were kept for this purpose.
At Edmonston in 1725, a fire engine was built to pump water from the coalworks using steam power.
Construction of the Level
In 1745 the estate of Duddingston was bought by the Duke of Abercorn. Almost immediately he leased it to John Biggar of Woolmet who began work on the sea level, starting it at the sea shore near Joppa.
In 1748, Biggar also leased the neighbouring estate of Niddry allowing him to extend the level and by 1752 the level had been extended well into the Niddry estate.
To extend the level through the Edmonston estate he would have needed agreement from Mr Wauchope who would no doubt agree to it because of the advantage he would gain by being able to use the level for his own coalworkings.
Normally a level cut through stone would be very costly and very slow, but because of the positioning of the edge seams, he was able to construct the level following the path of a coal seam. It was quicker and even had the advantage of producing coal at the same time.
At various points along it's path pits were dug to meet up with the level. Mines dug at right angles to the level (known as cross cut mines) would intersect the other edge seams allowing them all to be drained by a single sea-level.
Flooding of the Level
In a map of 1776, the level is shown as extending right up to the boundary of the Sheriffhall estate, but also shows that the level had been closed off by a wooden frame three feet within the Edmonston estate causing the water behind to rise over 36 feet.
Eventually, the amount of water from the higher up workings was too much and the Duddingston coal was flooded in 1790. Even with two fire engines, there was too much water to pump out.
This diagram shows the different estates, and the course of the level marked in blue. It was constructed through the coal seam known as the 'Gillespie Seam'. This seam was about 4 feet thick.
I have shown the line of the outcrops (the point where the seam meets the surface) of 8 of the edge seams but in fact there are another 11 I've missed out for clarity. The seams range in size from the 'Vexhim' at 6 inches up to the 'Great Seam' at 8 feet.
The Old Statistical Account for the Parish of Duddingston written in the 1790s has a good account of the problems associated with the level:
Coal.-Thirteen seams of coal have been discovered and wrought upon the estate of Dudingston. They are of various qualities, and some excellent in their kinds. They crop, as indeed the strata of all minerals upon this coals preserve the same inclination, to the west; the dip or declination, is nearly at an angle of 45 degrees from the horizon to the east, a circumstance which of itself must always have rendered the working of the coal difficult. Most of the above seams have been wrought from a very remote period of time, which cannot now be ascertained, where they approach the surface, and as far as a simple free level should clear them of water. Under the Duchess of Argyle, a rude machine composed of, and named, chain and buckets, was employed to raise the water in the mines from a greater depth. When the property fell into the possession of the late Earl of Abercom, the coal and salt works were at first let to Mr Bigger of Woolmet, an enterprising man, who opened a level from the sea, and carried it through the estates of Dudingston, Niddry, and part of Edmonston, up to Woolmet Bank, a powerful drain of above 3 miles in extent of most essential advantage to the more elevated coal works of the neighbouring proprietors, but eventually productive of ruin to that of Dudingston, besides opening the generating source of interminable law pleas. About the year 1763, the Earl of Abercom began to erect a steam engine of very considerable power upon the Dudingston coalliery, extending its operation to the depth of 52 fathoms. This engine was rendered useless in 1790 when on the 20th of March the whole seams of coal were overflowed and choaked from the communication of the level with the higher grounds. Before this period another engine of greater power, and upon a new construction had been erected near the Southern boundary of the parish to work the coal of Brunstane which lies beyond its limits. The shaft of this engine pit reaches to the depth of 60 fathoms, and intersects three seams of coal, the first 7 feet thick, the next 9, and the last 15. The other materials through which it descends, are chiefly very deep strata of a coarse red free-stone, some of clay, and nearest to the coal a kind of pyrites schist which the workmen call bads of bleas. The porous quality of the free-stone rock, the number of cutters, and above all the inauspicious communication of the fatal level, admit such an influx of water, as has all along rendered this undertaking singularly laborious and expensive, and at last reduced it to a very languishing condition. the number of colliers, bearers, and other workmen employed at the coalliery before 1790, used to be about 270. The number is new greatly reduced. " |
Note on John Biggar of Woolmet and Sir Archibald Hope
After John Biggar died in 1762, he was succeeded first by his brother Andrew Wallace who died in 1765, then a nephew Capt John McDowall. McDowall then made over his rights to the coal leases to his own brother-in-law Sir Archibald Hope. Hope already owned mines in Fife and also lived there, but moved to Pinkie near Inveresk in 1768.