AN EXTRACT FROM MY BOOK: HISTORIC STEAM BOILER EXPLOSIONS. www.sledgehammerengineeringpress.co.uk
Balbardie Colliery, Bathgate,
West Lothian
Tuesday 19th February 1895
The scene of destruction at Balbardie Colliery following the explosion of two Egg-Ended boilers on Tuesday 19th February 1895. A crowd of curious men, women and children survey the ruins of the devastated Boilerhouse from beneath the pit-head gear. Several men pose to the front of the two boilers that had been dislodged due to the explosion, and four more stand under the large water tank supported on an iron structure.
Courtesy of West Lothian Council
Balbardie Colliery which included Dovecot Pit was near Bathgate around twenty-two miles from Edinburgh. Both Balbardie Colliery and the Dovecot Pit was sunk around 1850 by a man named Hosie who originated from Falkirk. The mines produced good quality coal and also ironstone, both products then being in demand by the many local Ironworks.
“Serious Boiler Explosion – Two men killed and one injured,” shouted the headlines
of the West Lothian Courier of Saturday 23rd of February 1895.
“One of the most serious disasters known in the history of this neighbourhood occurred on Tuesday morning between eight and nine o’clock at Messrs. Walker & Cameron’s Dovecot Pit, Balbardie ...... resulting in the death of two men, and injury to a third.”
Events Leading Up To The Multiple Boiler
Explosions
It was twelve minutes past eight and the first rays of pale wintry sunshine was rapidly transforming the inky-black early morning sky into pink-tinged daylight, which sparkled from the heavy hoar frost coated pit-head gear and other tall structures on the Dovecot Pit bank.
John Adams, the Winding Engine-man was just about to commence winding the next two tubs of Balbardie coal from the depths of the deep shaft. Nearby in the Boilerhouse which contained six huge Egg-Ended boilers, fired from unsaleable, poor quality coal, the Colliery Engineer, Robert Yates and one of his boiler firemen, Richard Beswick were engaged in carrying out some minor adjustments to a small steam engine that drove a conveyor; another boiler fireman Hugh Borthwick was stoking the furnace of the No. 4 Boiler. Working beneath the pit-head structure shovelling coal into several iron-wheeled tubs were Robert Begbie and his workmate, John Harkins. Perched upon a heap of old sacking which had been his bed for the previous two nights, was Robert Strickland, a desperately poor, homeless chap, who had been allowed to sleep in the Boilerhouse, by the Engineer Yates, who pitied him.
It was just another busy working day, and all appeared to be fine. Three minutes later and a massive explosion erupted as No. 3 Boiler suddenly burst followed by the instantaneous explosion of No. 4 Boiler.
The colliery Boilerhouse contained a battery of six Egg-Ended, cylindrical boilers operated at a maximum working pressure of 45 psig, the steam fed into a common cast-iron main steam pipe supplied the pit winding engine, haulage engines, the mine pumps and electricity generating dynamos.
All six boilers were externally fired with a brick flue passing underneath each of them direct from the front ends containing the firegrate to the rear where they communicated with the main flue which led into the chimney. The boilers were numbered 1 to 6 commencing with the left-hand boiler when facing the ends containing the grates.
The battery of six boilers were set into brickwork in a row, each boiler being supported by brick pillars at the front and rear of the boilershells. They were also supported by sturdy iron brackets bolted to each side of the shell-plates which rested upon the dwarf brick walls which separated the flue of one boiler from those of the neighbouring boiler.
The ‘firehole’ or Boilerhouse, was a long, narrow flag-floored ‘Heath Robinson’ type of building which afforded protection from the weather at the firing ends only, the remainder of each of the row of six boilers projected beyond and were at the mercy of the weather, excepting that the boilershell plates were covered in a course of firebricks in the form of an arch; this method acted as a basic form of insulation; the downside being that regular inspection of the shell plates was impossible. Boiler plates could suffer undetected, significant corrosion, which in some recorded cases, led to some awesome explosions.
Constructional Details Of The Egg-Ended Boilers
No. 1 Boiler was constructed from wrought iron and was thirty feet overall by five feet in diameter. The shell was formed of seven strakes of plates, ¾ inch thick, lap-jointed and single riveted throughout, with rivets ? inch diameter at a two inch pitch. The hemispherical or Egg-Ends were constructed of six segments or petals that were finished with a cap or crown plate.
No. 2 Boiler was virtually constructed similar to No. 1 Boiler, but was only twenty seven feet long.
No. 3 Boiler was virtually the same also, but was thirty feet long.
No. 4 Boiler was again similar, but the shell consisted of eight strakes.
No. 5 Boiler was exactly the same as No. 4 Boiler.
No. 6 Boiler was exactly the same as No. 4 Boiler.
Nos. 1, 2 and 3 Boilers were fitted with:-
one - lever counterweighted safety valve
one - steam stop valve;
one- float water level indicator;
one - steam pressure gauge.
Nos. 4, 5 and 6 Boilers were each fitted with combined steam stop and level counter-weighted safety valves; they were also each fitted with:-
one - float water level indicator;
one - feedwater check valve;
one - steam pressure gauge.
Background History Of The Boilers
Nos. 1 and 3 Boilers – makers unknown, but had been installed in the colliery since before 1867, when Henry Walker purchased the business.
No. 2 Boiler was built by the Airdrie Iron Company and was installed in 1874.
Nos. 4, 5 and 6 Boilers were built by Hudson & Company of Coatbridge. No. 4 Boiler was purchased in 1878, and Nos. 5 and 6 Boilers in 1880. Over the years preceding the boiler explosions a number of repairs had been carried out.
No. 2 Boiler had received three shell patches and several cracked rivet holes had been ‘stopped’ by inserting ‘stop’ rivets. This involved reamering out the cracks and re-riveting using a considerably larger diameter rivet. Providing the length of the cracks were not too long, then this procedure was usually successful.
No. 3 Boiler had received a shell patch at the third strake from the firing end and several lap-fractures (lap-joint attachments) had been ‘stop riveted’.
No. 4 Boiler had not been patched, but had experienced lap-fraction which had been repaired by ‘stop rivets’. There was a history of leakage and heavy caulking.
Any minor boiler repairs had been carried out by Balbardie Colliery’s engineering staff. Major repairs i.e. patches etc. were executed by the Airdrie Iron Company’s Boilermakers.
Boiler Inspections
At the time of the explosions Nos. 1 and 5 Boilers were insured with the Scottish Boiler and Engine Inspection Company Limited, of Glasgow. No. 6 Boiler appears for some reason not to have been insured. The Insurance Company’s Inspecting Engineers’ reports were produced as follows:-
8th March 1893. General external inspection of all the five boilers.
14th June 1893. Internal and external inspection of No. 1 Boiler, and external inspection of Nos. 2, 3, 4 and 5 Boilers.
28th June 1893. Internal and external inspection of No. 3 Boiler.
8th July 1893. Internal and external inspection of No. 4 Boiler.
13th November 1893. General external inspection of the whole five boilers.
27th February 1894. General external inspection of the whole five boilers.
25th May 1894. Internal and external examination of No. 2 Boiler.
8th June 1894. Internal and external examination of No. 4 Boiler.
16th June 1894. Internal and external examination of No. 1 Boiler.
29th June 1894. Internal and external examination of No. 5 Boiler.
2nd November 1894. General external examination of the whole five boilers.
There was thus no inspection of No. 3 Boiler during the year 1894, or since 28th June 1893, the reason of which did not very clearly appear, for the insurance company had proposed to inspect it in 1894.
In connection with these inspections various recommendations were made, and in particular the fitting of the boilers’ manholes considered to be weak with compensating rings and also the supplementing of the float water indicators by glass water gauges. The former of these recommendations was adopted, but the latter was not. Sundry minor recommendations such as ‘stop-rivets’, caulking of seams, etc. were also made.
The Boiler Explosions
The explosions of the Nos. 3 and 4 Boilers was instantaneous, but it could not be ascertained which of the boilers exploded first. The two boilers burst at their circumferential lap-riveted shell seams due to cracked rivet holes. The explosion of the two boilers dislodged the complete battery of six. No. 2 Boiler had by the force of the blast, been thrown high in the air in such a manner as to turn a somersault, so that it was found lying across No. 1 Boiler, upside down. In its fall one of its plates was impales by the safety valve of No. 1 Boiler. The second shell strake from the rear end on its lower surface had ruptured for about twenty inches transversely. The brickwork flues and settings and steam and feedwater pipework systems were completely destroyed, with heaps of firebricks and the mangled remains of cast-iron pipework scattered all over the pit-head.
The Scottish Boiler and Engine Inspection Company’s Investigating Engineers’ report stated the cause of the boiler explosions:
The supporting brickwork under the No. 3 Boiler had suddenly disintegrated which consequently caused the underside of the boilershell plates which were subjected to the high temperature of the firegrate, to suddenly sag, which induced the cracks in the rivet holes of the circumferential strakes lap joints to ‘run’; thereby cracking wide open which in turn caused the boiler to burst.
Nos. 3 and 4 Boilers had parted asunder. In both cases the rent was a clean circumferential tear at the lap-seam, where two strakes of the shell plates were lap-riveted. The No. 3 Boiler was found to be fractured at the second to third circumferential seams. The No. 4 Boiler at the third and fourth circumferential joints. After splitting apart the end sections of both boilers were projected considerable distances by the explosion.
Nos. 5 and 6 Boilers though sustaining damage to the brickwork settings, were virtually structurally free from damage.
Cause Of The Explosion
The Investigating Engineers dismissed entirely the notion that excessive pressure was the cause of the explosions. The safety valves were found to be satisfactory and in good working order and all six boilers were joined together into a common steam main that ran across the front of the battery of boilers; they were therefore, not dependent on an individual safety valve.
At the time of the explosion, there was no evidence of excessive steam pressure on any of the boilers, as no safety valve was blowing off. There was also no evidence of a low water condition causing consequent overheating of the boiler shells. The water-float level indicators were in working order and the Investigating Engineers stated:
“We may here state that we are satisfied there was no impropriatory on the colliery owners in using only the water-float indicators. Such gauges are well recognised and perfectly good gauges if kept in working order ......there was no obligations on the boiler owners to have more than one, or to discard the float gauge in favour of the modern glass tube gauges.”
In regard to the overall condition of the boilers, the Engineers reported: “There were no discernible signs of metal wastage.”
The consensus reached by the Engineers was that the explosions were due to the sudden collapse of the supporting brickwork pillars under No. 3 Boiler that caused the lengthy boilershell to sag, then split amidships causing the massive release of water and steam, which in turn induced the No. 4 Boiler to burst open.
The Dead And Injured
At the point of the boilers exploding, Robert Yates the Colliery Engineer was projected a considerable distance by the phenomenal force of the blast. Upon landing on the hard, frozen ground, and despite being quite badly bruised, the Engineer rushed over to a mountainous heap of steaming rubble, that had been the colliery Boilerhouse to commence rescuing his men. Several more of the deeply shocked colliers and pit-men joined him. After digging with their bare hands to remove huge quantities of bricks, the men discovered the terribly disfigured and scalded remains of Richard Beswick. This was the man who, minutes before had been at the Engineer’s side, both of them working on a small steam engine. Hugh Borthwick, like Robert Yates was incredibly fortunate, for when the explosions occurred he had been walking along the ‘firing alley’ towards the other two men. He had sustained bruising to his shoulder due to being struck by a flying brick. The poor, homeless individual, Robert Strickland whom the boiler firemen had taken pity upon, was killed; his remains were carefully extricated from a significant heap of firebrick rubble.
John Adams, the colliery winding Engine Tenter was uninjured. The men loading coal into tubs at the pit-head, Robert Begbie and John Harkins were both violently knocked down on to the ground by the shock wave of the explosion, but were physically unharmed. Both men later reported seeing and hearing massive volumes of escaping steam roaring high above the wreckage of what had been the Boilerhouse. They were so frightened that they both ran off to the sanctuary of a nearby meadow.
Later, it was said, that the light casualty tally was due to the fact that the two boilers that exploded had broken in half, causing their hemispherical-shaped ends still connected to the boiler shell sections to be violently projected in opposite directions to eventually land without either striking the pit-head or the colliery workshops, where large numbers of men were working.
When the Board of Trade’s investigation took place several days subsequent to the disaster, colliery manager, Henry Beaton stated: “The boilers were inspected by the Scottish Boiler Insurance Company from time to time.” He also mentioned, “the recommendation of the insurance boiler inspector to mount water gauges to each of the boilers was not carried out” ...... and when questioned about the condition of the boiler feedwater, he said that, “the feedwater was pumped out of the coal-pit and sometimes contained large amounts of sediment ...... all six of the boilers were replenished with water around ten minutes prior to the explosion.”
The Aftermath
With the blast destroying the steam-powered winding engine the many colliers working underground had to escape through the Easton mine shaft. The explosions resulted in around £2,000 worth of damage and the three hundred colliery workers employed at the time were made idle until replacement boilers were installed and the various surface structures and buildings were re-constructed.