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Home , Beam engine, Cataract (beam engine), Cornish engine, Prestongrange

PRESTONGRANGE lO-inch ­ A MYTH EXPLODED

h u Kenneth Brown a o VI If S c F a The preserved 70-inch Cornish pumping engine at Prestongrange Colliery near E , now the Prestongrange Mining Museum, has always been assumed from E the inscription on the cast-iron beam to have been built by Harvey & Co. of Hayle in r 1874. The author has uncovered evidence that the engine is a little older than Robinson's famous 80-inch engine at South Crofty and enjoyed a similar working life of 101 years at four sites; moreover only the beam is of Harvey manufacture. This article is submitted in the hope that it may encourage other members to dip into the morass of literature and crumbling remains in an attempt to unravel other 'Cornish engine mysteries' which still puzzle us.

My list of surviving Cornish pumping engines published in the Society's newsletter No. 31 (November 1980) was challenged by a few members on the grounds that the history given for the Prestongrange 70-inch engine is wrong. I wrote individually to each explaining how I had arrived at my conclusions concerning the engine's age and parentage, and this aroused such fascinating correspondence that I realised that the story should be made available to members generally. The various research steps were taken very much as a 'learn as you go along' process, and it is hoped that they In themselves will be of some interest, quite apart from their final outcome. This research has proved beyond any doubtthatthe enginewas built by J.E. Mareof Plymouth Foundry in 1853 to the designs of the celebrated engineers Hocking and Loam. It was provided with the unusually long and shaft of 12ft and erected on Porter's shaft, Wheal Exmouth and Adams silver-lead mine at Christow In South Devon along with two , a third being added later. After a move to Wheal Neptune, Perranuthnoe, with two of the boilers in 1862 and another to Great Western Mines two miles away in 1869, the engine was purchased by Harvey & Co. in 1873 at a time of great depression in Cornish mining. They sold it early the following year to Prestongrange Colliery after providing a new beam to shorten the shaft stroke, new pitwork and 'lengthening' [sic] the rod. There it was erected by Matthew Loa~ of Liskeard whose father had erected a Perran Foundry 60 at a nearby pit some 3 years earlier. D.B. Barton in his excellent book The Cornish published in 1965

42 repeated the error caused by Harvey having put thei r name and the date 1874 on the beam. 1 My suspicion that the engine was not built by this firm because of the 'un­ Harvey' features goes back to 1952 when I was lucky enough to see her working. She was in very poor condition. The practice was to work her for two 3-hour periods each day, and she just about managed to make 2% strokes a minute, going flat out. There appeared to be no counterbalance and steam was taken throughout the whole stroke. Asteady 15 inches of vacuum was maintained not by an air but by a syphon pipe leading down the pit. As my visit was made after dark I had no chance to study the exhaust arrangements, which I now regret as the evidence has gone. The driver sat on a tall stool in front of the gearwork. He was able to shut the 'bottom handle' if the engine went short, but to close the steam horn without leaving his seat he used a long bar with a hook on the end. I vividly recall telling the late W.A. Michell about my visit and his laconic reply 'They never ought to be allowed to have an engine'! In the years which followed I must have spent many hours comparing photographs of engines, the small details on Prestongrange suggesting that the most likely builder was Perran Foundry. In fact, the detailing was the work of Hocking and Loam who left less to the engine builder than most designers of the time, and whose details were to some extent copied by Perran Foundry on engines of their own design. This became clear when I began examining the Society's collection of drawings held in the County Record Office at Truro. It seems that, also in 1853, H. & L. invited Harvey to tender for an exactly similar engine for Devon Burra Burra mine near Tavistock. 2 ln the event, a 50-inch engine by Gill & Rundle, Tavistock Iron Foundry and said to be the biggest ever made by the firm, went to Burra Burra instead.3 Traces of the house and the stack may yet be seen beside Brake Shaft (1981). Apart from the long stoke, the Prestongrange engine is notable in having separated top nozzles, the steam and equilibrium being on either side of the engine centreline, and no top nozzle governor. The gearwork is unusual in having the steam arbor at the bottom. The single plug rod is set well forward (to limit its travel, presumably) and the eduction pipe below the floor is offset to miss it. Barton states, probably correctly, that only a handful of these long-stroke 70s were built and lists four built in the early 1850s - none by Harvey.4 Of the Wheal Exmouth and Adams 70 he states: 'Built 1853, 12' e.b, by J.E. Mare & Co, Plymouth (engrs. Hocking & Loam) for Exmouth & Adams United (Christow), cost £2,552. Sold July 1862 to Old Wheal Neptune (Perranuthnoe) for £1,225 with two 1O-ton boilers. For sale May 1865 and re-erected September 1869 at Great Western Mines nearby, altered to 12ft x 10ft by G. Eustice & Son. For sale February 1873 .. .' At this point be becomes inaccurate, referring to a reworking of the mine renamed Wheal Florence and sale of the engine in July 1876 to a South Wales purchaser for £980. 4Actually this refers to a , different engine as we shall see. I have been through the relevant issues of Mining Journal at Library and can • confirm that the history of the 70 up to its operation at Great Western Mines is correct. In July 1862 tenders were invited5 'for taking down and erecting at Old Wheal Neptune, Marazion, , a 70-inch engine and two boilers now at Exmouth Mine .. .' (This was a silver-lead mine on Viscount Exmouth's estate near Canonteign House in the Teign Valley. A third there was unfit for further service.) Wheal Neptune is marked by a line of shafts running east-west about a quarter of a mile north of Perranuthnoe village. It was an old mine when a new company attempted to rework it in 1862, the "company paradoxically calling itself 'Old Wheal Neptune Mining Co. Ltd.'6 This has caused some confusion with East Wheal Neptune, another old copper mine slightly to the north-east which had the alternative name Old Wheal Neptune. However, since this property was also acquired by the 1862 company, the distinction had vanished by the time the Exmouth & Adams 70 was bought.

43 Top Left. Map showing the engine's four working sites.

Top Right. The well-known interior view of Prestongrange 70 taken by George Watkins when the engine had ceased work. The 'bleed' from the perpendicular pipe was apparently led to an exhaust steam turbine. The peculiarities of the gearwork are typical of Hocking & Loam designs of around 1850.

Bottom. The separate steam nozzle, the being worked from the bottom arbor.

44 Wheal Neptune had last stopped work in 1822 owing, it is said, to a legal dispute. A longitudinal section of that operation accompanying the 1862 prospectus shows a 52­ inch double acting engine? on New Engine shaft. The Exmouth &Adams70, however, was erected near the middle of the sett on Trevelyan's shaft, an enlarged horse-whim shaft.8 Maximum depth was said to be 103fm below adit (30fm). Lack of capital caused the company to be wound up in May 1864, the 70 being left boarded up and greased. The scene now shifts two miles to the east. In May 1869 we learn in a report from the newly-formed Great Western Mines:9 'Thomas' engine shaft has been enlarged, timbered, cased and divided from surface to deep adit ... At surface we have taken out the 70-inch engine from Old Wheal Neptune Mine and removed it with the two boilers to a convenient spot for refixing; also removed a large quantity of stone from there for building the new enginehouse ...' So the house went with the engine. From further reports in MJ that year by the agents at Great Western, captains Edward Thomas and Edmund Thomas, we learn that the engine went to work at Thomas' shaft in September, with efforts being directed at further deepening the shaft in very hard ground. This reworking, too, proved to be somewhat short-lived. The shaft, heavily overgrown, may still be seen. The link with Prestongrange was a fortuitous discovery made whilst scanning through the 1873 Harvey 'out' letter books lO in search of something else. In a letter dated 27 March to Matthew Loam at Liskeard, with whom Harveys were evidently on good terms, William Husband wrote: 'The 70 at Great Western Mine is for sale and should make a good engine ...' Next day he wrote again: 'The 70 at Great Western without boilers stands us in about £1,400. Will you join us in that and sell her in joint account? She is 12ft stroke. She would make a good engine with a new beam making stroke in shaft 10ft ...' It seems Loam declined for next we learn that Harvey tried to sell the engine, without openly identifying it, to East Hetton Colliery in County Durham for £2,000. However, Loam must have come back to Harvey for on 9 June 1873 Husband wrote him thus: 'The West Gwennap Consols people want the (Great Western) 70-inch engine and , would probably take it providing your friends don't ...' (As we shall see, 'your friends' is the operative phrase!) A week later Husband followed up with: 'Mr Eustice, the engineer to the mine, told me that the 70-inch is in excellent order and did her work well. The was cut to shorted the stroke as they had not room in the shaft for such a long stroke .. .' So Barton is wrong about Eustice having altered the engine to 12ft by 10ft, he merely worked the engine at the shorter stroke. I am indebted to David Spence MBE, who is in charge at Prestongrange and an expert on the mines of , for pointing out that a Cornish family called Kitto had interests in Prestongrange Colliery. Matthew Loam was married to Patience Kitto but the connection must go back much further for his father, Michael Loam, is on record as having erected a Perran Foundry 60-inch engine at the neighbouring • Dolphingstone Pit (right beside the Kings Cross-Edinburgh main line) in 1847-8. This doubtless explains Husband's reference to 'your friends'. Incidentally, that same 60­ inch engine survived until the 1950s at Fleets Colliery a few miles away, where I saw it, and David Spence can relate interesting experiences with her during the last war. (In the last year, the Fleets 60's air pump has been excavated and is now on display at Prestong range.) On 3 October 1873 Husband wrote to Loam: 'I think the Great Western 70 is worth With new beam £1,800. The cost of taking the old one back would be £180. We have no vessel but think you could process freight for about 15/- per ton - we shall be quite content for you to make the best bargain you can for the 70 .. .' On 11 October he wrote: 'With regard to the Great Western 70-inch engine, we will for the sum named Include the cost of lengthening the piston rod [to restore the full length of stroke in the

45 cylinder] but cannot include the putting the eng ine generally to good working order. " We have had great deal of repairs for the 70, much more then could be anticipated from your report'.12 One of the problems with the Harvey letter books is that the 'flimsies' on which copies of outgoing letters were kept have not stood up well to the passage of time. Many are entirely or partly illegible which means that it is often difficult to establish continuity. For this reason, we do not know what 'the sum named' was. Nor do we learn directly where the engine was destined; we can only deduce this circumstantially. Prestongrange is mentioned in the next letter from Husband to Loam which is decipherable, dated 9 November 1873: 'Re Prestongrange Colliery, we hereby undertake to make and deliver at Preston, Firth of Forth ... a pair of winding engines, cylinders 26-in diamater ... regarding the pitwork, we are pushing on for completion as fast as we can.' In the next letter dated 27 November we read: '... we will make and deliver f.o.b. at the port where the 70-inch engine has to be delivered two sets of (26­ inch) pitwork as en numerated below for sum of £1,100 .. .'13 The discovery of this correspondence was a major breakthrough. I was then 99.9 per cent certain that the Great Western 70 (originally the Wheal Exmouth & Adams 70) with its new beam was indeed despatched from Hayle to Prestongrange Colliery early in 1874 - which corresponds with the date on the beam - along with a and two lifts of 26-inch pitwork. Harvey had made a new piston rod and done other repairs (presumably at cost) on the engine, and M. Loam & Sons superintended erection at Prestongrange. But what about the last 0.1 per cent of doubt? Then I realised that we are dealing with an unusual design of engine of which only very few were made; moreover with the engine still in existence and whose original enginehouse, albeit empty since 1862, was still standing. Could I find a corroborative link? A feature of both enginehouses is that they are unusually wide for a 70-inch engine, making the cylinder doorway appear smaller than it really is. So one bitterly cold evening, well fortified with 'a wee nip' from David Spence, I grubbed around in the cockpit at Prestongrange searching for an explanation. I found just what was needed! A beautifully executed cast-iron girder, albiet with a patch on it where it must have got broken during one of the moves, spans from wall to wall just beneath the driver's floor. Its purpose is to carry a guide for the single plug rod and is without doubt original work. (Most Cornish engines have the plug rod guide fixed to the eduction pipe carrying the exhaust into the condenser and so do not need a special girder.) This beam must have fixed the width of the house at every place the engine stood. It is about 17ft 3in long but one cannot be absolutely precise since the feet at the ends are embedded an unknown distance in the masonry. Anotherexciting discovery in the cockpit is that to miss the plug rod, theeduction pipe runs slightly off centreline, tothe left as one looks towards the shaft. However, the pipe is clearly not original as It IS made up in short lengths and manages to pass out through the bob wall centrally beneath the plug door. In the company of John Wellington and Rodney Law, I then revisited the house at Exmouth & Adams. To my delight I found not only a reCess in the wall each side of the cockpit where the feet of the cast-iron girder had been built in, but a distinct gash on one side where the masonry had been chiselled away in 1862 to extract it. A cross­ measurement was taken, with some difficuIty due to stinging nettles and debris, which proved to be within three inches of that at Prestongrange. Under the circumstances, this is an acceptable margin of error. The eduction pipe opening at Exmouth & AdarTl S is offset from centreline byexactlythe right amount butto the right, notto the left! Thl~ puzzled us momentarily but is explained by the alterations to the eduction pipe, WhlC t I suspect have something todo with the builder of the Prestongrange enginehouse nO

46 having been properly instructed. With both the documentary and the physical evidence having come together so nicely, I thought it would round the research off neatly to establish the engine's two other sites. Wheal Neptune proved the more difficult, in fact the precise position of Trevelyan's shaft is now obscured. It is marked by a large burrow on the west side of, and immediately adjacent to, the road running south from Goldsithney into , Perranuthnoe village. Just north of it are two dwelling houses and I suspect that the one closest to the burrow is probably where the engine stood. The other house is shown on the 1880 25-inch O.S. and was probably the count house - it is called 'Wheal Neptune'. (The directors of the 1862 company could never run to the cost of a steam whim so the possibilityof locating the shaft from the whim loadings does not exist!) We already know that the enginehouse masonry went with the 70 to Great Western. Several shafts running east and west from Trevelyan's are still traceable, including New Engine shaft where the 52-inch engine stood prior to the 1822 closure. Great Western is a large property which straggles along both sides of the A394 for the best part of a mile and which never seems to have been worked except in isolated bits, all of which have individual names. We know from Mining Journal that the 70 stood on Thomas' Engine shaft, so I started with the early O.S. map. Engine shaft on the latter corresponds with Thomas' shaft in Dines, and lies just north of the A394 nearly 900 yards east-south-east of the Falmouth Packet inn. All that can be seen from the main road is the intersection of th ree hedgerows in fields with a shed partly built of masonry. Closer inspection, however, reveals that two of the fields are at a higher level and conceal a large burrow. Moreover, the shaft itself with a large balance pit is still open though completely overgrown with bushes and brambles. The old O.S. map shows the enginehouse, roofless, which stood with its back to what is now the A394, facing north. The shed today is clearly formed out of part of the boilerhouse. (We know that the engine is a 'left-hand' engine so the steam supply should have entered the house from the left when facing the - or right when facing the shaft - at each site.) There were at least two other pumping engines on different parts of Great Western

I during the period in the 1860s and 70s when attempts were being made to rework the sett. I believe that in his statement regarding disposal of the 70, Barton confused the three engines as one! There was, for instance, a 40-inch engine on the Grylls Wheal Florence section. And there was a 50 which George Eustice was erecting in November 1871,14 little more than a year before the 70 was offered for sale. There is evidence on the ground for this engine in the shape of the bob wall and par.t of a house which still stand on Wheal Georgia Engine shaft on Rosudgeon Common, some 350yards south of the Falmouth Packet. This is nearly half a mile from Thomas' Engine shaft and the 70 could not possibly have stood here for the width inside the house at driver's floor level is barely 14ft. This dimension is fully compatible with a 50, however, and I believe this was the engine which Barton says went to South Wales. The £980 is a more likely price for a 50 than a 70, even allowing for depressed secondhand engine prices at the time. Having more or less established where the engine stood during the eventful first 21 years of its life, we now turn to its history at Prestongrange for which I am indebted to David Spence. We have seen that Harvey supplied two 26-inch plunger lifts with the engine. Next news of the engine comes from the report of a visit by the Mining Institute of in 1900. At that time the 70 was working three 22-inch plunger lifts and one 17-inch, the lowest probably being at the Beggar Seam 780 feet below surface. The shaft stroke was 10ft. By this time the Summerlee Iron Company had taken overthe pit and soon afterwards the three 22-inch poles were replaced by two 28-inch putting more load on the engine and necessitating the fitting of the prominent kingpost and bridle truss to the beam. I can do no bet~er than quote from the museum's own

47 literature:15 A The pump rods, of Oregon pine, are 23 inches square from the surface to the top box lift pu mp and the total weig ht of the pu mp rods, rams, and side rods is pro~ about 105 tons. Calculations of the engine beam strength showed that the beam as it stood was not capable of bearing the extra load imposed by the installation of the larger , consequently a strenthening truss was designed. Fitting of this truss was no mean feat, bearing in mind that, at that time, no electrical power was available for drilling machines, etc. A specially constructed boring bar, driven by a small was used for drilling the large holes in the sidesof the beam to receive the pins in the eyes of the tiebars. When the truss has been erected, a system of levers was fitted to the beam for the purpose of measuring the deflection to ensure that the beam was not unduly stressed when tightening the tie bars. After the National Coal Board took over the colliery, their engineers carried out calculations from which the correct position of the adjusting screws without overstressing the beam could be maintained. Like most long-lived Cornish engines, the Prestongrange engine suffered a few smashes, which led to some ingenious repairs being carried out. About 1916 the piston rod is reported to have broken as the engine took steam with the piston at the top of its stroke. The impact caused by the falling piston broke the cylinder bottom and cracked the cylinder wall. A new cylinder bottom was cast and itwas decided to attempt to repair the cylinder by clamping. Heavy cast iron rings were made in halves and these were bolted together round the cylinder. The cracks were caul ked with a mixture of red lead and boiled linseed oi I, after which the set­ screws round the rings were tightened to close the cracks. No further trouble was experienced until 1938 when the piston rod again broke under the same conditions. Another cylinder bottom was fitted and the repair of the walls was achieved by removing the clamping rings and cutting dovetailed grooves inserting and clamping up strips of soft copper. The engine continued working in this condition until 1954, its working life of 101 years being exactly thesameas Robinson's 80. The Prestongrange engine, now an industrial monument. has become the centrepiece of a historic site for the mining industry. The first written record of coal mining in Britain is the charter given to the monks of Newbattle in 1210 to work the coal in the Grange of Preston. The first coal harbour, Acheson's Haven, lay across the road and the first railway in Scotland was laid on wooden rails from Tranent to Cockenzie, some three miles down the coast. The Prestongrangesite is being laid out to show the various different stages in miners' efforts to win coal. The main display will endeavour to simulate a colliery atthe beginning of the 20th century when the deeper mines were sunk. A Grant Ritchie steam wi nding engine 1909, dismantled from Newcraighall Colliery, is being reassembled. Other machinery is on view in the powerhouse, and the foundations of more colliery equipment exposed. While much progress has been made in recent years since the East Lothian District Council took over the site, the Cornish engine stands like a sentinel in its isolated house, the only piece of machinery to escape scrapping after the pit closed. Unless the shaft is cleared and some means found of putting a load on the engine. it seems unlikely that it will ever work under steam again. A pronounced sag in the top chamber ... floor and main girder bears witness to the number of times the engine came indoors n hard. There is no mention of the steam case in the official documentation, one of assumes this was dispensed with when the first repair was carried out on the cylinder W in 1916. The clamping rings referred to above are exposed to view. ar

48 A pleasing feature of the engine is that the restoration to working order of its floating bOX has been carried out along with a considerable clean-up and painting programme: all credit to David Spence and his largely voluntary team.

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The engine house of Porter's 70at Wheal Exmouth and Adams near Christow must surely be one of the hardest of all to photograph, owing to trees and ivy. This photograph, taken by John Wellington some years ago, shows the rear of the house beside the road. Note the cylinder door and window joinery put back in position after removal of the engine in 1862.

49 G p T T p

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J(?~lI\O"~;~'" HOIJu. SVrvivill.~ M-lh"U o.."'(ou...l 'P/ff"~ ~Iu.-ft; W~~ 5....ol1+t.. tl. ,4.I-s /h.iTe.J. ~il'H:f-Iu.J.. ~j"4!. leVOll . Sketch of the remains around Porter's shaft today.

There could not be a greater contrast between the grime, noise and bustle of Prestongrange Colliery when active, and the rustic solitude of the ivy-clad enginehouse at Porter's Shaft, Wheal Exmouth & Adams. As so graphically described by Barton,16 special architectural treatment was applied to the buildings because they could be seen from Canonteign House, despite the planting of a screen of trees. For many years after the mine closed it seems that the enginehouse was maintained so that it would not appear to be a ruin; even the cylinder door and window frames, removed in order to take the engine out of the house, were subsequently put back in position though without final pointing up. This feature may still be seen (1981). The roof, which I am told survived until recently, has gone along with the top of the splendid octagonal stack. Another recent casualty is the whim house nearby which contained a 22-inch Perran Foundry engine - this was removed to improve a sharp bend in the lane which passes close to the shaft. Only the stack and loading survive. Hamilton Jenkin describes operations around Porter's shaft in his second volume of Mines of Devon, just published (1982).17 The lane passes close behind the enginehouse of the 70 and on the opposite side is a dry stone retaining wall, contemporary with the screen of trees, which must have made it very difficult in 1862 to remove a 44ft long engine beam. Sure enough, right in line with the cylinder doorway and almost 44ft from it is a gash in the wall where some of the stones have been displaced! At this distance of time we shall never know whether this happened accidentally or whether the engineers had to do it in order to swing the beam round on to its bogies. But it does show what gems of discovery about the problems which faced engineers of a less mechanised age may yet be made by thoSe with the leisure time and practised eye ...

50 Grid references: porter's shaft, Wheal Exmouth & Adams, Christow, Devon: 838830 Trevelyan's shaft, Wheal Neptune, Perranuthnoe, Cornwall: 541300 Thomas' Engine shaft, Great Western Mines, Kennegy Downs, Cornwall: 566294 prestongrange Colliery pumping shaft, near , Edinburgh: 373737

REFERENCES 1. D.B. Barton, The Cornish Beam Engine, p.62, 10. Harvey letter books, CRO, Truro. footnote 3. 11. ibid. 2 Harvey & Company, 'in' letters, County 12. ibid. Record Office, Truro (CRO). 13. ibid. 3. A.K. Hamilton Jenkin, Mines of Devon: The 14. T.R. Harris, 'Some lesser known Cornish Southern Area, vol. 1, p.69. engineers', Trevithick Society Journal, NO.5, 4. Barton, The Cornish Beam Engine, pp.61-2 1977, p.36. (both references). 15. East Lothian District Council, Dept. of 5. Mining Journal, 12 July 1862. Physical Planning, Council Buildings, 6 Prospectus published in Mining Journal, 14 Haddington EH41 3HA, Prestongrange beam June 1862, p.411. engine, technical information sheet. 7 Lean's Historical Statement of the Steam 16. Barton, The Cornish Beam Engine, p.174. Engines in Cornwall, p.44. 17. Hamilton Jenkin, Mines of Devon: North and 8. Mining Journal, 14 February 1863, p.107. East of Dartmoor, pp.153-7. 9. Mining Journal, 1 May 1869.

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