Description
The Cornwall and Isles of Scilly SMR contains no reference to Wheal Drea, which was centred around Kenidjack hamlet, the main shafts during the later 19th Century being at SW 3653 3227 (Wheal Drea Shaft) and at SW 3665 3242 (Greenland's Shaft). Little could be discovered about the history of the mine, though Noall (1973, 132) mentions this area in quoting the lease of a sett by the Lords of Kentdjack to John Thomas of St Just in 1795, the area granted being as far south as: "... the road leading from Kenidjack to Henry Boyens' Smith Shop except twenty fathoms to the North of the said Road on Kins-an-Drea Load which is already in grant to the adventurers in Kinsandrea Tin Mine, and so far East as to adjoin with the several tin bounds called Kenidjack Cliff Bounds and Wheal Edward Bounds'. Noall also mentions (1973, 133) an alternative name for the Wheal Drea main lode - Cercendry -almost certainly a variant of Kinsandrea, whilst the Colonel Oates collection mentions a mine called Polandrea - probably sited near the pool now spanned by the clapper bridge below the hamlet. It seems probable from Moody's map of 1778 that the mine reworked as Wheal Gendall was the earlier (and later) Wheal Drea. The late reworking of the mine during the second half of the 19th Century was from a new shaft and to far greater depth, and there is little evidence that the earlier shafts to the west of the hamlet were reused. The earlier history of this mine is described under Wheal Gendall (below, 92741). The mine was incorporated into the Wheal Owles group in about 1859, having worked independently for some years during the earlier part of the 19th Century. According to Noall (1973, 138) the engine shaft at Wheal Drea was being deepened during 1871, when it was discovered that it intersected three lodes at the 160 fathom level. Three years later, parts of the Wheal Owles sett were suspended and allowed to fill with water, but work continued in Wheal Drea. It seems probable that it was at Wheal Drea in 1881 that the Champion rock drill was introduced to the Wheal Owles mines, the compressor being powered by an old waterwheel on the Boscean side of the stream. In 1882, the Wheal Drea miners holed into Boscean workings -an indication (had it been realised) that the underground survey as erroneous. In 1884, the Wheal Drea section was abandoned. On 11th January 1893, the West Wheal Owles miners holed into the enormous mass of water which had filled Wheal Drea to surface. According to Jim. Polglase, air pressure resulting from the inrush of water caused a run of ground on the outcrop of Huel an Vor Lode, a feature which is now covered by the agricultural tip on the hillside to the west of Kenidjack hamlet (92737). Another run of ground is supposed to have been visible until a few years ago on the Boscean side of the stream near the Poor House. The few visible remains of the mid-19th Century mine are clustered within a small area to the east and south-east of Kenidjack hamlet. The shaft which measures 12'6"" x 4'6" has a massive drystone collar and a wire mesh fence for security and stands atop a high dump, now in the process of being replaced by a grille. Richard Jenkin suggested (Letter of 26.9.88) that the reason for this tall dump is that "the group of mining venturers, who exploited a very rich lode of tin in a very restricted area, were at loggerheads with their neighbours who were also mining venturers. Being without space to stack their deads (waste stone) they extended the collar around their shaft to a height above ground of more than 25ft with dressed granite and tipped their waste stone around it as the work proceeded. This abortion now exists close by the very old village of Kenidjack". The shaft is open to some depth and is regularly used by underground exploration groups. On its northern side are the remains of a stonework feature which appears to be part of a (buried) balance bob pit. A horse whim may have also have been sited on this side of the shaft. Martin Mount also reports a small stone-lined shallow adit opening onto the Kenidjack Stream from the shaft. Moody's map of 1778 shows this exiting to the stream at SW 3625 3242, but particularly dense vegetation covering partly-backfilled outcrop workings on the southern part of Wheal Edward Lode made this too dangerous to investigate. The adit was the source of water pumped by the Polglase's using Kenidjack Stamps water wheel (92758). The shaft dump is an impressive pile of mineralised rock towering above the Kenidjack road. Its upper surface has been extensively dug into by mineral collectors, who have displaced rock down the dump sides, creating a number of deep, unstable and dangerous excavations on its surface. A large quantity of material has been dug away from the foot of the dump for roadstone over the years, gradually exposing the drystone shaft collar, whose freestanding sections have subsequently collapsed down the southern dump face. The engine house which survives to the north of the shaft wound from Greenland Shaft at SW 3665 3242, though Brown has suggested that it may have pumped via flatrods in Wheal Drea Shaft. A hollow behind the engine house, and the construction of the rear wall suggests that there may be an additional shallow pumping shaft in this area. The engine house is in good condition (with the exception of its rear wall), and still retains substantial portions of its boiler house walls, which he on the western side of the house. A plain and sturdy rotative beam engine house measuring 7.6m x 5.2m in plan, and standing to 12.0m high, this deceptively standard looking building was constructed of granite throughout. The stonework of the bob wall is of squared blocks, but the other walls are of rubble masonry, shaped stone being confined to quoins and the framings of the wall openings. No tie bars were installed. AR wall openings are square headed, granite being used for the external lintels, timber for the internal lintels (except above the boiler house door, where granite was used for both). The tall plug doorway (4.35m high x 1.05m wide) in the bob wall is flanked on the offside by a cut-out for the flywheel. At the base of this is a small opening through the wall. It is unclear whether this engine was double acting. There are no traces of the anchorages for the additional bolts securing the beam trunnion, nor of a link motion opening through the wall. There are windows in the offside wall on the ground and middle floors - the lower Window being set just behind the bob wall, the middle floor window at the centre of the elevation. `The nearside wall is windowless - the boiler house door is set just behind the bob wall rear face; just above the level of its lintel, and set to its rear is the steam pipe entry. The upper section of the rear wall has collapsed. At its base is a granite-lintelled cylinder door (1.8m high x 0.95m wide). The positions of the windows in this wall are unclear, though it is likely that there would have been a middle floor light. The stonework at the head of the wall was thought to be consistent with this house having been intended to have a back bob opening (evinced by the lack of any gable stonework and the greater thickness of this wall over the side walls). Photographs dating to the 1960's recently made available to the National Trust by Bill North, a local mining historian, show two elongated square-headed windows in this facade, whilst excavations behind the engine house found no trace of a shaft. There are no surviving traces of the spring beam openings. A further curiosity about this house is that there appears to have been no main girder - there are no pockets or openings in the walls whatsoever for this feature. At the base of the rear wall is a small tunnel giving access to the bottoms of the cylinder bed bolts. Inside the house, other oddities were found. The locations of the longitudinal bearers for both upper floors could be seen on the rear wall, but on the face of the bob wall, only two middle floor joist pockets (rather than the four in the rear wall) could be seen - one adjacent to the plug door opening on the offside, one flush with the nearside wall. There appear to have been quite massive lateral timbers spanning the cataract pit. Brick-infilled putlog holes are visible in two rows on the face of the nearside wall only. The bedstone is a single granite slab bearing four bolt holes, and has a central slot running from the middle of the block to its front face. Some of the structure of the boiler house, which was constructed onto the nearside of the engine house, survives. Although the rear end of this structure (which projects to the rear of the engine house) has until recently been in use as an agricultural shed, the forward end of the building has been demolished. The rear walls contain three unusual slit openings, unlike any other boiler house recorded by CAU. The boiler house appears to have been 11.5m long x 3.0m wide, and where it is intact, stands to 2.0m high. At its rear end it was constructed on top of a revetted plinth. The engine pond is sited a little way to the north-east of the engine house. Now a small paddock (the wall has been breached) it measures about 12m square, and has enclosing banks 1.2m high. The chimney, attached to the nearside rear corner of the engine house, appears to be in good condition. It is constructed in the usual fashion, with a stone lower section and brick top, the two materials separated by a stepped brick drip ring. The remains of the loadings extend to the front of the house on the nearside of the plug door. These consist of a line of large granite blocks about five metres long bearing a number of bolt holes; to the nearside again is the partially infilled flywheel slot. The ground to the nearside again is occupied by a small grass-grown dump of material on which can be seen a small rectangular concrete machine base and some small iron bolts, suggesting that an upright axle whim cage was mounted here. Greenland's Shaft lies about 100m to the north-east, surrounded by dumps, and is choked - this is described under Wheal Owles, above. At the rear of the engine house, where Sharpe (1992) has suggested that a weed-grown hollow might indicate the site of a shallow pumping shaft, investigations by CAU for Percy Williams Ltd. in October 1997 revealed a backfilled 0.65m wide trench cut into rab. This was interpreted as a drain serving both the condenser pit and the flywheel pit, and must have been cut at an early stage in the construction of the house. There were no signs of timber or stone lining, nor of any capping material, and it may be that the trench oniginally contained an iron pipe which was removed on the closure of the mine. The course of the trench indicated that it drained into the field to the east some way downslope. The dry just to the west of the engine house is one of only a small number of such mine structures which survive in Cornwall. This building, constructed of granite rubble masonry with quoins to openings and door surrounds under a hipped scantle slate roof, measures 16.39m long x 6.18m wide, standing to between 2.4m (downslope end) and 4.2m high (upslope end). A modern un-rendered blockwork extension has been added to the south-westem corner of the building, this measuring 4.26m x 4.79m in plan and standing to 3.75m high and having a corrugated cement asbestos sheet roof. The walls of the dry are 0.67m thick (2'). On the eastern side of the building are three widows set high in the wall. The fenestration is modem and slightly shorter than the originals, the cills having been raised. Internally these openings are splayed. On the western elevation, there were probably again three window openings. In these cases the window depths have been deepened to fit the present fenestration. The opening at the northern end of this wall was non-original, the southernmost window had been converted into a doorway to give access to the extension, whilst a new opening had been made to provide a main access to the building from this side. This was fitted with a sliding galvanised sheet covered door. In the southern elevation was a single, boarded up, non-original window opening. To the north, the original double door had been partly blocked up, an access being retained in its western half and a ventilator inserted into the upper half of its eastern side. The roof had been cement slurried externally and the scantling was wet-laid on lime plaster. Three of the red clay ridge tiles had been set slightly proud to provide roof ventilation. A corroding steel water tank on concrete supports stood next to the north-eastern end of the building. Internally, the conversion of the building to a cowshed saw the walls cement rendered to just over 1.0m from ground level over the original limewash/distemper finish. Raised cement rendered floors had been created on either side of a central drain, whilst eight feed stalls were created (six along the eastern side) using blockwork partitions. The remains of a water supply to drinkers was still in place. The northern end of the building had been partitioned off in blockwork carrying vertically-set planking. Access to the northern end of the building did not prove possible at the time of the initial survey (it was in use as a chicken shed), but Richard Liddicoat's drawings showed it to be subdivided by a further partition. The roof trusses were simple 'A' frames and a number had been repaired by scarfing at their ends. The blockwork extension had a large doorway on its northern side (originally closed by a galvanised steel sheet clad sliding door). There was a small boarded up window in the southern elevation and two in the western elevation, the larger of these having been boarded up. A concrete surface had been laid around the main entrances to the shippon and extension to provide a ramped access from the nearby track.