Underground Ragstone Quarries in Kent A Brief Overview LeGear

407 underground ragstone quarries in kent: a brief overview rod legear R agstone is a pale bluish-grey sandy limestone occurring in layers interspersed with buff-coloured calcareous sandstone (Hassock) in the Hythe Beds of the Lower Greensand. It has been extensively worked for use as a building stone from at least the Roman period and was usually obtained from open pits, especially where nearby rivers or sea ports could be used for transport. The principal quarries have been around Borough Green, Maidstone and Hythe. In a few areas, probably for local use, the stone was at various times quarried underground from mined galleries. Hosey Common, Westerham (TQ 4541 5321 - TQ 4543 5274) A hard building stone has been obtained from extensive underground quarries at Hosey Common, 1km to the south-east of Westerham village. Whether this stone can truly be called Kentish Ragstone is a matter of debate amongst some geologists. It is described as ‘a good quality building stone’ in a geological memoir,1 whereas just few km eastward the same stratum is referred to as Kentish Rag. The lithography of the Hythe Beds changes from east to west with the lime content in the Ragstone decreasing and the limestone beds becoming more of a calcareous sandstone. Locally it is accepted as Ragstone with several buildings, including the Church, built from it, as are local estate walls, other boundary walls, etc. For the purpose of continuity it will be referred to in this paper as Ragstone or Rag. T he underground galleries of the quarries are known to locals as the ‘Westerham Caves’, the ‘Ragstone Mines’ or simply as the ‘Caves’. It is apparent that this hard building stone has been worked for a considerable time from an outcrop of the Hythe Beds to the south-east of the village where an almost continuous old quarry face runs in a north-south direction for about 0.7km along the eastern side of a dry valley. The outcrop was first worked in a series of small open pits (although the sections are now obscured with time and weathering), before following the good quality stone underground. ROD LEGEAR 408 A t what period it became necessary to quarry the stone underground is not clear, but the late seventeenth century is probable. It was the old working faces of the northern pits that had adits driven into them to start the first of the underground quarries. As time progressed, so the underground exploitation of the stone moved further southwards down the old quarry line. T he local church is built of Ragstone and dates from the medieval period, the stone probably coming from the earliest open quarries, i.e. the northernmost part of the site. The majority of the stone from the later mines has been used locally for houses, walls, road repairs, etc. For example, Hosey school was built of Rag in 1828 and enlarged at various times between 1873 and 1899. A house at Hosey (Charts Edge) was said to have been built ‘before the first world war’ with stone from ‘the caves’. T he quarries show a distinct diversity of mining styles from north to south along the valley although the stratigraphy of the Hythe Beds is fairly consistent throughout all the mines and a typical section of the strata (taken in Series 3) is as follows: R r oof f riable greyish/buff sandstone 1 F firm and compact grey sandstone 30cm thick 2 S soft and friable buff sandstone 26cm thick 3 F firm compact buff sandstone 13cm thick 4 Harder buff sandstone 13cm thick 5 V very hard grey Ragstone 23cm thick 6 Hard buff sandstone 30cm thick 7 V very hard dark grey Ragstone 40cm thick A number of natural fissures or ‘gulls’ bisect the underground passages in all of the series. The gulls are up to 1.3m wide and are filled with geologically recent material. In many of the galleries the fill of the gulls has fallen into the mined cavities and the voids thus created are migrating upward toward the surface. A number of plans of varying quality have been made of the underground quarries, in the main by caving clubs in the 1950s and 60s. A plan of what is now known as Series 3 was made between 1939 and 1947 by Messrs Birchby, Peet and Rumbold and published in the above Geological memoir.2 T he writer conducted a re-survey of series 1, 2 and 3 over a four-week period in 1975. Although series 1a had been accessible for some years UNDERGROUND RAGSTONEragstone QUARRIES IN KENT : A BRIEF overview 409 it was not properly surveyed until Paul Sowan of the Croydon Natural History and Scientific Society undertook the task in 1987. Series 4, 5 and 6 were plotted by Harry Pearman and the writer in 2003. A surface survey to tie together all the underground surveys was completed by Mike Clinch and the writer in 2003 and the resulting overall layout is shown in Fig. 1. F ig. 1 Underground quarries at Hosey Common, Westerham ROD LEGEAR 410 T he underground extraction of the Ragstone was started by driving a tunnel into an existing quarry face. This operation produced a great deal of waste stone in proportion to the sought-after Ragstone. This waste material was removed and dumped in low mounds near the entrance. As the tunnel progressed deeper the sides of the tunnel were utilised to dump waste so less had to be hauled back the increasing distance to the surface (see Plate I). As subsequent galleries were driven parallel to the first, cross-cut tunnels were dug which enabled the waste to be barrowed into the worked out galleries. In many areas the original height of the galleries has been reduced to around 1.4m or less by this backfill. In one gallery in series 3 only 0.4m of space above the compact fill has been left. The utilising of previously dug voids to deposit waste meant that only the Ragstone was brought to the surface which reduced the size of any external spoil heaps to a minimum, a condition that may have been stipulated by the landowner before digging commenced. I n all the quarries surveyed at Westerham it is evident that the tunnels were worked from north to south with the southern galleries being the last worked in each series. The southern galleries tend to retain their full working height having had no backfill deposited in them. There is evidence that the stone was transported out to the surface on sledges, as opposed to Plate I U nderground Gallery in Series 3 at Westerham. Note waste stone at sides of tunnel UNDERGROUND RAGSTONEragstone QUARRIES IN KENT : A BRIEF overview 411 wheeled carts, in at least some of the quarries. Excavations carried out by the writer in 1976 within the floor debris of full height tunnels in Series 1 revealed a number of sledge ruts in the southern galleries. I t is most likely that the underground quarries were worked only as and when stone was required. A stonemason or builder would obtain permission from the Lord of the Manor or his agent to extract material from the mines. He would assemble a few labourers, a sledge, small wheeled cart or barrow for underground transportation of the heavy Rag, and a cart to haul it to the building site. It is doubtful that there was ever a full-time mining operation on site for any length of time. The entrances were sealed after enough stone was extracted, probably to comply with a clause in the agreement with the landowner which may have required the sealing of any entrances when underground work ceased. Series 1a and 1 This northern series consist of long parallel adits driven horizontally into the hillside with few cross galleries and little or no attempt to increase the extraction ratio by exploiting the material between the tunnels. These two quarries were not originally connected underground; the single modern connecting point being made by members of a caving club digging through a natural fissure some time in the 1950s. The working adits were originally, on average, 3.70m wide and 2.10m high. Series 1a/1 was the first of the underground quarries and whilst it is not impossible that it was dug in the medieval period it is more likely to be later, probably in the late seventeenth/early eighteenth century. Series 2 This small set of galleries was never developed fully due to the nature of the ground at this point. Several severe roof falls, one of which has reached the surface, made working this area dangerous and unproductive. Instead of driving tunnels deep into the hillside, the miners had to work around an area of unstable ground with limited success. An early eighteenth-century date of operations is likely. Series 3 A well developed system worked on the ‘pillar and stall’ principle with regular cross galleries at right angles to leave roughly square pillars to support the ground above. This particular working is the most efficient, in mining terms, of all the quarries at Hosey Common. A haulage track-way from this quarry runs west along a specially constructed causeway across the valley to the common. The techniques used by the miners are consistent throughout Series 3 which suggests that the quarry was worked for either a building project that required a great deal of stone, or a number of smaller jobs being undertaken at roughly the same time. Series 3 was the last of the northern quarries to have been dug and evidence from the mining techniques used points to a date in the early-mid nineteenth century. ROD LEGEAR 412 The southern group (4, 5 and 6) Three sets of previously unrecorded galleries to the south of the known mines were entered in 2003 following exploratory excavation by members of the Kent Underground Research Group, with permission of the land owner. These quarries had not been entered since stone extraction had ceased and therefore had not been disturbed. The technique of working the Ragstone in this series was seen to be similar to the other underground quarries with only the Ragstone being removed from the galleries, the inferior stone being barrowed into previously dug tunnels. Thus many of the mine galleries are only accessible by crawling over backfill which in some places reaches within 0.5m of the roof. The tunnels last worked by the miners in each set are in contrast on average 1.8m high. Series 4 Upon entering this, the most extensive of the three mines of the southern group, a careful examination was made to record any artefacts and dateable material. As expected in this type of underground quarry, finds were not abundant but the following items were noted: A A an old rusting iron spade abandoned by the miner in the last worked gallery. B F fragments of an iron cooking bowl or cauldron, found on top of backfill. C S several pieces of a leather shoe or boot, also discarded on top of backfill. D A a dateable clay pipe near to a sealed entrance. E T the impression of a number of beer bottle labels on the wall in the last worked gallery. These were formed by removing the label from a beer bottle and placing it on the wall of the tunnel. It was held in place by the moisture in the rock and after time the paper rotted away leaving a ‘transfer’ of the design on the wall. A similar set exists in the southern galleries of Series 3 although they have been badly vandalised. F S several initials and dates smoked into the roof by candle, mainly in the last worked gallery. T he method of working the stone varies slightly throughout the quarry which may imply that it was dug intermittently over a number of years, the entrances being re-opened when a new building project commenced. A very overgrown cart track runs from this quarry to join the larger haulage way from Series 3 just east of the causeway across the valley floor. T he clay pipe was made by a Phillip Richmond of Tunbridge who is shown in Kelly’s Directory as being a pipe maker from 1845. The smoked graffiti was observed to be of late nineteenth-century style and a date of 1891 (repeated several times) confirms. The beer bottle labels were from UNDERGROUND RAGSTONEragstone QUARRIES IN KENT : A BRIEF overview 413 the Martin and Sons Brewery in Westerham. Martin moved to Westerham from Bermondsey and started brewing in 1860. The labels in Series 3 are from G. Bushell, Watkins & Co who were brewing in the town from 1840. This indicates that at least one entrance to this series was open at that time although actual mining may have ceased a little earlier and the pipe and graffiti were the results of adventurous exploring by locals before sealing. The 1861 census returns for Westerham lists four stonemasons, one of whom was employing six men.3 It would appear, therefore, that Series 4 was probably being worked from the mid- nineteenth century and sealed around 1891-2. Series 5 and 6 These two small mines were the last to be dug at Westerham and are relatively small with no notable features or artefacts. The amount of stone extracted from them shows they were supplying fairly modest building projects. Of the two, Series 6 was the very last dug and it is most unlikely that any further sets of tunnels exist south of series 6. Although they were not very extensive each quarry had its own trackway for transporting the stone. The two tracks join after a short distance and then a single track runs north to join that from series 4. S eries 5 and 6 were excavated later than series 4 with Series 6 being the last dug. It is likely that stone from this particular mine was used in the building of Charts Edge in the early twentieth century. After the Great War the greater use of brick for new build projects and a better transport infrastructure enabled Ragstone to be obtained from large commercial pits, which made local quarrying uneconomic. Mote Park (Maidstone): Eastern Quarry (TQ 7778 5419) T his site is located in the south-east portion of Mote Park where a small outcrop of Ragstone was once worked from an open quarry. This small working was extended by driving galleries beneath the southern boundary of the park. When mining ceased and the adits were abandoned, a number of roof falls occurred near the base of the quarry face which made access only available to those who were willing to crawl through the unstable debris that partially blocked the entrances. In the late 1950s Maidstone Borough Council ordered the site to be filled and a large amount of rubble was tipped into the old quarry and bulldozed up to the working face thus blocking all access to the underground workings. This action was taken because of the concern caused by groups of children exploring and playing in the ‘caves’. W ith permission of the Council, the Kent Underground Research Group began digging in a small natural fissure in the south-east corner of the old quarry in May 1990. The object of the excavation was to gain access to the mine so that a survey and an historical investigation could ROD LEGEAR 414 F ig. 2 Underground quarry at Mote Park, Maidstone UNDERGROUND RAGSTONEragstone QUARRIES IN KENT : A BRIEF overview 415 be undertaken. As far as can be determined no plans of the layout of the passages were made before they were sealed. Some survey marks were observed when access was gained, but the surveyors (probably a caving club in the 1940s or 50s) do not appear to have published their results. A fter gaining entry a survey to determine the layout and extent of the workings was undertaken using standard cave survey techniques. Approximately 400m of accessible passages were recorded (Fig. 2). Unlike the Westerham quarries where the stone was worked from galleries with pillars or large baulks of un-worked material left to support the roof, at Maidstone almost all the pillars were removed, the roof being supported by waste stone or ‘deads’ (Plate II). The Ragstone was extracted in large blocks, the exact size of which was determined by the masons’ requirements. The stone was roughly trimmed underground before being hauled out to the surface on small carts or sledges. T he layers of poor quality stone that had to be removed in order to extract the best Ragstone, together with the waste from the trimming process, were stacked up to roof level and retained by carefully constructed dry-stone walls. The survey shows a number of narrow access ‘roads’ passing through large areas of backfill. Typical Access Roadway through backfill in Mote Park East Quarry. The passageway shown is 2.1m high and 1.5m wide Plate IIii ROD LEGEAR 416 The Hythe Beds in this area contain a large number of vertical fissures similar to those at Westerham. The galleries of the quarry are bisected by a number of these ‘gulls’, some of which have had their relatively loose fill drop into the passages. The miners have cleared this debris away during the working of the mine and it is clear that working conditions would not have been pleasant or safe. As well as the problems caused by the fissures, the miners had to contend with a portion of the Hythe Beds that had several cracks in other planes and a roof level that frequently split away from the strata above. This has caused several major roof failures and falls both during the working life of the quarry and after it was abandoned. A number of fossils were observed during the survey including two large ammonites. A s expected, there was no direct dating evidence found in the underground workings. It appears that the site had remained more or less accessible from the time of its abandonment up to the middle of the twentieth century. The tunnels had been visited by countless groups and individuals so that the possibility of casual artefacts remaining in-situ was very remote. The methods used to extract the stone had not changed in centuries so only a broad date could be deduced from the mining techniques. On the slim evidence available the writer suggests a date of mining operations between the mid eighteenth and the mid nineteenth century. Mote Park (Maidstone): Western Quarry (TQ 7725 5437) A few hundred metres west of the surveyed site is the location of another set of underground workings which extend beyond the park boundary. They were sealed at the same time as the above quarry and no access is now possible. From verbal descriptions from local residents who remembered the ‘caves’ they were less extensive than the quarry described above but had similar fissures and roof falls. Two of the entrances were wide low arches which had tunnels that were blocked after 10-15m by roof falls. A third entrance to the west gave access to about 30m of passages. W illington Street Area (Maidstone) T he extensive open-cast Ragstone quarries to the east of Mote Park and north-west of Otham church have been worked for a considerable length of time, possibly as far back as the Roman occupation. The old quarries are now much obscured by housing development which has taken place in recent years in the quarry floors to the east of Willington Street. Some small scale underground quarrying took place in both the eastern and western sides of the quarries although most have been sealed in the past by falls from the quarry face or deliberate attempts to block off the entrances UNDERGROUND RAGSTONEragstone QUARRIES IN KENT : A BRIEF overview 417 for safety reasons. The locations and extent of all of these mined galleries are not known, only a few having been recorded. T hose that did remain accessible for any length of time acquired local names such as ‘Willington Street Caves’, ‘Otham Cave’, ‘Senacre Wood Cave’, ‘Senacre Cave’ and ‘Spot Lane Quarry Tunnels’, etc. This creates some confusion, however, as some tunnels seem to have gone by more than one name. Willington Street Caves (Approx. TQtq 786 543) This small underground quarry was located in the western edge of the open pit and had a brief mention in the Maidstone geological memoir.4 In 1973 a survey of the remaining accessible galleries was produced by Terry Reeve and is reproduced as Fig. 3. Senacre Wood Caves (sometimes known as Otham Caves) (TQtq 7851 5407) This set of underground workings was visited by members of various groups and individuals in the 1930s and 40s and was located south of the above Willington Street Caves. G. Peet of the London Speleological Society visited the site in 1938 and again after the war when he remarked that ‘the caves had undergone many changes by falls since 1938 and in places they are not altogether safe’. In March 1943 a survey of the site was undertaken by John Hooper and a description published in a national caving journal.5 In 1994 the Kent Underground Research Group was asked F ig. 3 Willington Street ‘Caves’. ROD LEGEAR 418 to assist in an investigation to determine the extent of possible underground workings in the area of a housing development at Ufton Close. A ccess was gained to the workings from the rear of a property on the east side of ‘The Beams’. The rear gardens of this residential road terminate at the base of the old quarry face which is some 5.0m high at this point. A small opening at the bottom of the face gave access into the remains of an underground quarry. A survey was made which, when compared with Hooper’s plan, showed that the excavation was Senacre Wood Cave (Fig. 4). A n examination of the site showed that the stone had been worked in F ig. 4 Senacre Wood ‘Caves’.a similar way to the Mote Park quarry with large areas backfilled with waste and retained by dry-stone walls. A number of fissures or ‘gulls’ were noted some of which had falls migrating toward the surface. From interviews with householders of neighbouring properties it was apparent that a number of other ‘caves’ in the area had once existed but were now blocked. Some bricked up entrances could be seen in other gardens. I n 1990 Adrian Pearce of the Kent Underground Research Group interviewed many elderly residents of the area and the information for the following sites has been derived from this oral record: S pot Lane Quarry Tunnels: said to be on the eastern side of Spot Lane Quarry and consisted of five or six adits approximately 6.0m long. UNDERGROUND RAGSTONEragstone QUARRIES IN KENT : A BRIEF overview 419 S enacre Cave: a small set of tunnels also in the eastern side of the above quarry but further south than those above. Described as consisting of several short connected galleries, located roughly opposite the Willington Street Caves described above. ConclCLusions T he amount of Ragstone extracted from underground workings represents but a very small fraction of that obtained from large open pits. Quarrying stone underground is generally less efficient than open-cast unless the overburden becomes uneconomical to remove or the surface land is not to be disturbed. It is probable that some underground sites have been destroyed by later open quarrying. The examples shown in this short account demonstrates that underground quarrying, whilst not common, was significant locally. It is hoped that this paper will stimulate archive research providing more information on these and other underground quarries in the county. acknowledgements T he writer would like to thank the following for their invaluable assistance during the underground investigations and the preparation of this paper: S. Caiger, M. Clinch, R. Clomby, J. Packer, H. Pearman and T. Reeve. endnotes 1 D dines et al., Geology of the Country around Sevenoaks and Tonbridge, HMSOso (1969), p. 68. 2 Ibid., p. 76. 3 T thomas Horseman Senior, aged 60. His son, aged 32, is also listed as a stonemason. 4 B b. Worssam et al., Geology of the Country around Maidstone HMSOso (1963), p. 38. 5 British Caver, vol. 12 (1944), 46.