Paul Henry Richard James Newbold & Ors v The Coal Authority

Introduction

1. This reference concerns Wentworth Woodhouse, one of the greatest private houses in Great Britain. It was built in the second quarter of the 18 th century in open country a few miles from Rotherham. Its façade is one of the longest of any house in Europe and its interiors the finest of any Georgian stately home. The house and its associated structures are now in a state of deterioration which the claimants attribute to subsidence caused by the effects of coal mining for which, in their reference to the Tribunal, they seek compensation “likely to be in excess of £100m”.

2. Beneath the house and its landscaped park lie the productive seams of the South Yorkshire coalfield which had been mined in the area at surface outcrops from the early middle-ages. The Fitzwilliam family, whose ancestors had owned Wentworth Woodhouse since the time of the Normans, were mining coal reserves on their estates by 1750. The invention of Newcomen’s steam powered engine allowed deeper mine shafts to be sunk in the 18 th and 19 th centuries to meet the insatiable demand created by the industrial revolution and by the increasing use of coal to power ships, railways and factories. By the 1920s deep seams were being exploited under the park and close to or under the buildings and structures at Wentworth Woodhouse. The 1947 nationalisation of the coal industry brought intensified mining beneath the park and formal gardens which continued until the 1960s, by which time the mines in the immediate vicinity were exhausted or uneconomic.

3. Wentworth Woodhouse is now owned by the claimants, who are brothers. They acquired the house and grounds through a family company in 1999. One of the original claimants was Mr Paul Newbold, who has died since the making of the reference.

4. The respondent, the Coal Authority, was established by the Coal Industry Act 1994 in succession to the British Coal Corporation (formerly the National Coal Board), and is the body responsible for meeting claims under the Coal Mining Subsidence Act 1991 for compensation for damage caused by mining subsidence. These proceedings were commenced by notice of reference given on 22 December 2009 under section 40(1) of the 1991 Act . The reference had been preceded by the service of two damage notices under section 3 of the Act , the first given on 31 January 2007 and the second on 3 August 2009. The Coal Authority initially resisted the claims on the grounds that the damage notices did not comply with the statutory requirements, so the Tribunal directed that the validity of the notices be determined as a preliminary issue. On 23 May 2013, the Court of Appeal confirmed the Tribunal’s earlier determination that both notices were valid: Newbold v The Coal Authority [2013] EWCA Civ 584 .

5. The issue now for consideration is whether any of the deterioration in four separate parts of the buildings and structures at Wentworth Woodhouse is “subsidence damage” within the meaning of section 1(1) of the 1991 Act , such that the cost of its remediation will fall on the Coal Authority. The four areas selected for consideration are (1) a line through the east front of the north wing of the mansion following the area putatively influenced by the Wentworth fault; (2) the north tower of the mansion and the adjacent north quadrant; (3) the south terrace wall; and (4) the camellia house. On 1 May 2014 the Tribunal directed the trial of preliminary issues to identify whether, in relation to those four specific areas, coal mining has caused any subsidence damage. The evidence and the arguments before us went rather further, the real debate being not simply whether subsidence damage had occurred at any time (which in many instances was not contentious), but whether such damage was the result of a renewed phase of ground movement occurring since the 1990s, long after conventional expectations would have ruled out historic mining as a cause of damage.

6. The claimants contend that the great majority of the damage at Wentworth Woodhouse is at least likely to have been caused by ground movement attributable to mining. The primary trigger for this movement is suggested to be the collapse of old mine workings as a result of their inundation by rising ground water following the general cessation of pumping in the South Yorkshire coalfield in the 1990s. The Coal Authority asserts the contrary: that ground movement caused by mining ended many decades ago and that Wentworth Woodhouse is largely stable, with the damage visible in the four selected areas being either historic or attributable to a variety of other causes, including neglect and decay. Representation and witnesses

7. At the hearing of the preliminary issues Mr Michael Barnes QC and Mr Eian Caws of counsel appeared for the claimants, instructed by David Cooper & Co, solicitors. Mr Giles Newbold, one of the claimants, Mr David Scholey MICE, a Chartered Civil Engineer with Arup, Mr Tom McWilliams, Estate Manager at Wentworth Woodhouse and Mr David Pearson, who farms the Home Farm as tenant of the Fitzwilliam Wentworth Estate, gave factual evidence. Expert evidence in respect of mining and ground engineering matters was given by Mr Peter Stevenson B Eng C Eng MICE C Geol FGS, and structural engineering evidence was given by Dr Gregor Beattie PhD, M Eng C Eng, both of Arup.

8. Ms Dominique Rawley QC appeared for the Coal Authority, instructed by DLA Piper, solicitors. She called Mr Lee Cammack, the Coal Authority’s Project Manager responsible for public safety and subsidence claims in Yorkshire and Nottinghamshire, who gave evidence of fact. Expert evidence on mining and subsidence matters was given by Mr David Wilshaw FRICS IEng FIMMM MQB of Wardell Armstrong and structural engineering evidence by Mr Clive Richardson BSc (Hons) C Eng FICE FIStructE IHBC of AECOM (formerly URS).

9. We are grateful to all those who participated in the reference for their very considerable efforts and their assistance to us in determining these preliminary issues. Statutory provisions

10. Section 2(1) of the 1991 Act imposes a duty, originally on the British Coal Corporation but now on the Coal Authority, to take remedial action in respect of “subsidence damage” to any property. Subsidence damage is defined by section 1(1) of the Act and means “any damage to land, or to structures or works on, in or over land, caused by the withdrawal of support from land in connection with lawful coal mining operations.” By section 1(2) any alteration to the level or gradient of land which does not affect its fitness for the use for which it might reasonably have been expected to be put to, is not to be regarded as damage for this purpose.

11. By section 2(2) the Coal Authority’s statutory duty is to take remedial action in respect of subsidence damage to any property either by the execution of remedial works, or by the making of payments in respect of remedial work carried out by another person, or by the making of a payment in respect of the depreciation in the value of the damaged property. Each of these potential courses of remedial action is governed by detailed provisions of the Act which it is not necessary to consider at this stage of the reference.

12. The duty to take remedial action arises only if a notice is given to the Coal Authority, referred to as a damage notice, stating that the damage has occurred and containing further prescribed information ( section 3(1) -(2)). The person who gives a damage notice is referred to in the Act as ‘the claimant’, an expression extended to include any successor in title of that person ( section 3(6) ).

13. A damage notice must be given within six years of the first date on which any person entitled to give the notice had the knowledge required to found a claim in respect of the damage ( section 3(3) -(5)).

14. Section 4(1) of the Act requires that, as soon as practicable after receiving a damage notice, the Coal Authority must inform the claimant whether or not they agree that they have a remedial obligation in respect of the damage specified in the damage notice. In this case, after an interval of six months for investigation, the Coal Authority responded to the damage notice given by the claimants in January 2007 denying that they had any such obligation.

15. Any question arising under the Act is required by section 40(1) to be referred to the Upper Tribunal for determination. Under section 44(2) a reference must be made either within three years of the date on which the Coal Authority are in breach of their remedial obligation, or within the time for serving a damage notice, whichever expires last.

16. There are substantial issues between the parties in this reference on limitation but they do not form part of the preliminary issues to be determined at this stage, so it is unnecessary to refer further to the relevant statutory provisions.

17. It is relevant also to refer at this stage to the provisions of the Act dealing with the burden of proof on the question whether any damage is subsidence damage. Section 40(2) of the Act allocates that burden between the parties as follows: “Where in any proceedings under this Act the question arises whether any damage to property is subsidence damage, and it is shown that the nature of the damage and the circumstances are such as to indicate that the damage may be subsidence damage, the onus shall be on the Coal Authority to show that the damage is not subsidence damage.”

18. The burden of proving that damage has occurred is on the claimants. Mr Barnes QC submitted on behalf of the claimants that the onus was on them also to establish, by reference to the nature of the damage and other circumstances, that the damage “may be subsidence damage” i.e. that it may have been caused by the withdrawal of support from land in connection with mining operations. He suggested that in this case that burden was relatively light, and that once it was discharged the onus would shift to the Coal Authority to establish on the balance of probabilities that the damage under consideration was not subsidence damage but had some cause other than the withdrawal of support from land in connection with mining operations. For the Coal Authority Ms Rawley QC emphasised that before the Coal Authority was required to prove anything, it was for the claimants to prove the mechanism of damage for which they contended, that it had occurred, and to identify the items of damage which had been caused by that mechanism. We return to this issue at paragraph 326 below.

19. There is a legal issue between the parties on whether the mechanism of damage which the claimants say has afflicted Wentworth Woodhouse in the relatively recent past is such that the damage is “subsidence damage” within the meaning of the 1991 Act , but we will return to that issue at the conclusion of this decision. Historical background

20. The Wentworth family lived at Wentworth in the West Riding of Yorkshire for almost a thousand years, from the 11 th to the 20 th centuries. In 1640 Charles I bestowed the title of Earl of Strafford on one of the family’s most controversial ancestors, his adviser and favourite, Thomas Wentworth, but the King proved powerless to resist Parliament’s demand for Strafford’s attainder and execution in 1641. The Earl’s direct descendants produced no male heir and his extensive estates in the West Riding and in Ireland eventually passed in 1695 to an infant cousin, Thomas Watson-Wentworth, who was created Marquess of Rockingham by George II in 1746 in gratitude for his support of the Hanoverian regime.

21. The building of the west front of the house was commenced by the 1st Marquess in 1725 on the footprint of Strafford’s Jacobean mansion, and was completed in 1735. By that time the erection of the vast east front had already begun and it was structurally complete by 1742. After the death of the 1st Marquess in 1750, the palatial interiors were completed by his son Charles, the 2nd Marquess of Rockingham, a supporter of the constitutional rights of the American colonists and George III’s Prime Minister in two short-lived administrations from 1765-66 and for a further three months in 1782. A Whig grandee, a noted sportsman and a patron of both art and science, Rockingham installed an 80 ft telescope on the roof of the house and in 1779 completed the construction of the largest stable block in England in its grounds. His horse Whistlejacket won him a record purse over four miles at York in 1759. For more than 200 years Stubbs’ magnificent portrait of the rearing thoroughbred, painted in honour of that victory, was displayed in the Whistlejacket Room at Wentworth Woodhouse before finding a second home in the National Gallery in 1997.

22. The house with all its contents passed on the death of the 2 nd Marquess in 1782 to his nephew, William Fitzwilliam, 4th Earl Fitzwilliam. In 1790 Fitzwilliam commissioned Humphry Repton, one of Georgian England’s most celebrated landscape gardeners, to redesign the park and lay out the formal gardens.

23. Underpinning it all lay coal. The spectacular wealth required to complete and inhabit Wentworth Woodhouse and its landscaped park was generated from the middle of the 18 th century by iron works, by the manufacture of china and by progressive agriculture on a home farm of 2,000 acres and tenanted estates in Yorkshire and Ireland, but increasingly in the 19 th and 20 th centuries by the mining of coal from around and beneath the estate. The Earls Fitzwilliam were not only landowners but mine owners whose collieries at Elsecar and New Stubbins made them amongst the richest families in Victorian and Edwardian England. It was from those same Fitzwilliam pits that seams of coal encircling the house were worked for the family’s profit until 1 January 1947, when nationalisation vested the coal mining industry in public ownership. With nationalisation came retribution, or so it seemed, as the historic park and gardens were brutally mined by open cast techniques and the beleaguered house was threatened with requisition.

24. In 1948 Peter Fitzwilliam, the 8th Earl, was killed in a flying accident with his lover, Kathleen “Kick” Kennedy, sister of JFK. He left no male heir and the title and estate passed to a distant, childless cousin of great age. On his death the destination of the Earldom and all that went with it was settled by the High Court in a dispute over the legitimacy of the elder of two yet further distant Fitzwilliam cousins.

25. In 1950, after open cast mining had laid waste to the park and gardens, Wentworth Woodhouse entered perhaps the most prosaic phase of its history. Rotherham Borough Council took a lease for a term of 200 years of the greater part of the house, the stable block and the grounds to provide a home for the Lady Mabel College of Physical Education, named in honour of the 7 th Earl Fitzwilliam’s aunt. The College operated at Wentworth Woodhouse until the lease was surrendered following the death of the 10 th and last Earl Fitzwilliam in 1986. The Fitzwilliam estate, including the park, the home farm and the village of Wentworth, had by then already passed to an independent preservation trust (the Fitzwilliam Wentworth Amenity Trust), but the house and its immediate grounds and stables were acquired in 1988 by the pharmaceutical entrepreneur Professor Wensley Haydon-Baillie. The failure of his fortune saw the principal buildings repossessed by Swiss mortgagees who disposed of them in May 1999 to the claimants, Paul, Marcus and Giles Newbold. Their father, Clifford Newbold, was a distinguished architect who aspired to restore Wentworth Woodhouse to its former splendour. Clifford Newbold died at the age of 88 on 29 April 2015 having succeeded in 2012 in opening the house to the public for the first time. An overview of the buildings and structures at Wentworth Woodhouse

26. The house itself is 180 metres long and 50 metres wide and has almost 400 rooms. Pevsner’s description gives a sense of its grandeur and introduces some of the features of significance in these preliminary issues: “ Wentworth Woodhouse is two eighteenth century houses merging with one another. Incorporated in the earlier of the two are the few remains of an earlier house of c.1630. The two eighteenth century houses can never be seen together. One faces West, the other East - their centres are nearly, though not entirely in line. There is considerable difference in level between them, which amounts almost to a full storey. The differences in character are even more startling. The West front of c.1725-30 is gay and profusely decorated, the East front begun c.1734 is staid, reserved and correct. It is also exceedingly ambitious - with its 600 ft. the longest front of any English country house … The East front consists of a principal block of nineteen bays, with lower eleven-bay wings connected by convex quadrants to higher, square angle pavilions with square domed roofs and lanterns. The main house is clearly derived from Wanstead in Essex: rusticated ground floor, piano nobile, and in addition, in the nine-bay centre of the block, another half-storey, and a portico of six giant Corinthian columns. The wings were originally only one and a half storeys high, and had plain broad five-bay pediments. These were altered by John Carr from 1782-4. Due to him are the giant Doric columns and the three-bay pediments. The height of the quadrants was also raised. The angle pavilions however are original. The whole of this majestic if not imaginative East front is a screen to hide the complex and irregular ranges behind. A large quadrangular stable block, on a scale to emulate the house, was added by John Carr in 1768. The stone and glass Camellia House was built at some distance from the house, to the South West, in the early nineteenth century. Attached to the back of this is a summer house of earlier date .”

27. Pevsner therefore identifies the east front of the house with the complex and irregular structures behind, the square pavilions (or towers) which stand at the northern and southern ends of the east front, and the 19 th century camellia house in the garden. The scale of the stable block attracts his attention, but he makes no mention here of the south terrace wall, the fourth of the specific areas of interest which are the subject of these preliminary issues and which have been explored in the evidence. We will describe those features in more detail when we come to consider the extent to which they have been damaged. The lie of the land

28. The house and the former mining village of Wentworth situated about 2km to the northwest are located along a west to east trending ridge on the south side of a hill. The mansion itself has a north south alignment so that while the land rises gently from the west façade it slopes down to the east and more steeply to the south. As the length of the house runs across the general slope of the land it obstructs the path of surface or sub-surface water running down the slope, as does the terrace wall on the southern side of the site.

29. The stable block is to the north west of the house at a distance of about 400 metres. The camellia house lies at a similar distance in the formal gardens, which are to the west and south of the house. These are bounded on the south by a terrace retained by a 400 metre terrace wall constructed in 1735; the sloping ground below the terrace is approximately 3 or 4 metres lower than the level of the terrace itself. To the north of the gardens, between the mansion and the stable block, runs a ha-ha wall.

30. The general geology of the district is of the middle coal measures: relatively thin beds of coal formed about 350 million years ago interspersed with sandstone, shale and clay in repetitive sequences or strata. There are thirteen named coal seams within approximately 350m depth beneath the site, of which seven have been mined.

31. A geological fault, referred to as the Wentworth (or Elsecar) Fault, runs on a north west to south east alignment through the centre of the site and passes beneath the mansion and stable block. The fault downthrows to the south by 40 metres (i.e. the geological strata to the south of the fault zone have sheared and dropped so that they are now 40 metres below the same strata to the north of the zone). The experts agree that where geological faults are present these can be re-activated by mining activity resulting in localised ground movements and damage significantly greater than the general subsidence profile which would be expected in their absence. The claimants also contend that reactivation of a fault can occur as a result of the recovery of groundwater long after the cessation of mining. An overview of mining techniques

32. Four principal methods of mining have been employed in the vicinity of Wentworth Woodhouse. They are opencast working, pillar and stall working, longwall working and room and pillar working. We include here a brief description of those methods.

33. “Opencast” working is, as its name suggests, the extraction of coal directly from the surface of the land. This method does not involve the sinking of mineshafts, which are required for the mining of deep seams by the other techniques.

34. “Pillar and stall” working is the oldest method of underground working. Coal is removed from the seam in a grid pattern leaving pillars of coal in situ to prop up the roof and the rock or overburden which lies between the seam and the surface. When mining is completed what is left of the seam are the open areas from which the coal has been removed and a series of pillars of un-worked coal which continue to provide support to the roof and the overburden.

35. “Longwall” working is the most common modern method of extraction. A main pathway or heading is created from the bottom of the mine shaft from which, at right angles, two parallel tunnels are dug into the coal seam. A wall of coal is then progressively extracted from the seam between the two parallel tunnels by mechanical methods, and the cut coal is carried away through the tunnels. At the working face the roof is held up by hydraulic jacks but as extraction progresses these jacks are advanced and the roof of the mined area is left unsupported and deliberately allowed to collapse. The collapsed area is referred to as the “goaf”.

36. A key feature of the longwall method of working is that it involves the removal of all or nearly all of the coal in the seam (hence it is referred to as “total extraction”) making it the most productive and efficient deep mining technique. Modern mechanised longwall mining, such as has been used at least since the 1960s, employs a wide working face or panel of up to 350 metres. A similar approach was used before mechanisation, but “old” longwall working in the 1920s progressed using narrower panels down to about 40 metres in width.

37. The “old” longwall technique was employed before the advent of hydraulic props and mechanisation and relied on the manual extraction of coal. At the working face the roof rocks were supported by timber props which would have been removed to allow for the collapse of the roof areas as the face moved forward, and re-used as the seam progressed. Direct access to the face may have been via a single tunnel as illustrated in a construction industry publication we were shown (CIREA SP32 of 1984).

38. Generally in longwall mining the wider the extracted panel of coal the more comprehensive will be the collapse of the roof. The collapse of the strata overlaying the worked seam causes the migration of movement to the surface, resulting in subsidence. It is agreed between the experts that where longwall techniques have been adopted this movement at the surface will normally occur either immediately or shortly after the withdrawal of support by extraction of the coal.

39. The area at the surface which is liable to be affected by subsidence as a result of longwall mining is not confined to the area lying immediately above the underground working but extends for a distance surrounding the worked out area. The extent of this zone of influence can be predicted by a simple calculation: the boundary of the area liable to be affected to any extent is within an angle of draw of 35 degrees from the worked face (which corresponds to 0.7 x depth of working); experience nevertheless demonstrates that damage from mining induced movement is generally confined within a more restricted area, described by an angle of draw of 26 degrees (corresponding to 0.5 x depth of working). Thus a longwall seam worked at a depth of 100 metres might usually be expected to cause damage at the surface in an area extending for 50 metres beyond the point immediately above the limit of the worked face, but that area could extend to up to 70 metres.

40. The fourth method of mining employs the “room and pillar” technique. This is akin to pillar and stall working in that it does not involve total extraction of all of the coal in the seam but leaves un-worked pillars as support for the roof as mining progresses. Using the room and pillar technique a greater proportion of the coal is extracted from the seam by mining long “rooms” rather than the smaller “stalls” found when the pillar and stall method is used. The long rooms or passageways in which the mining takes place are about 20 metres wide and the pillars which separate them from each other are continuous walls or ribs comprised of the un-worked coal. The extent to which the roof of the mined seam would collapse when the room and pillar technique was used was a matter of controversy between the experts to which we will return later. Predicting subsidence: the Subsidence Engineers Handbook and Mulpan

41. The extensive history of mining in Great Britain has allowed mining engineers to acquire considerable experience of the effects of underground mining on surface structures. The severity and extent of these effects differ depending on the depth of the seam, its thickness, the dimensions of the coal panel worked, the angle of the seam and other matters. By the 1960s practical experience permitted the development of an empirical model for estimating mining subsidence, published in 1966 as the Subsidence Engineers Handbook (“SEH”). This model did not purport to be a comprehensive predictive or diagnostic tool for all situations and was limited in its application to comparatively simple mine layouts.

42. We were shown extracts from the 1966 and 1975 editions of the SEH. By 1975 the model was underpinned by between 150 and 200 case studies of subsidence which had been caused by longwall mining, from which predictive tables and charts were compiled. Only two of the case studies involved mining in panels narrower than 50 metres and most were for very much larger panels; the narrowest longwall panel included in the studies was about 40 metres wide, of which there was a single example, while at least 98% of the panels studied exceeded 100 metres.

43. In the 1980s the data collected in the SEH was used to create a computerised software package known as “Mulpan”. As well as predicting subsidence Mulpan includes an assessment of “strain” or the effect of lateral (rather than vertical) ground movement, but less reliance seems to be placed on this measure. Mulpan has become a standard tool used by the Coal Authority in assessing claims for compensation; an assessment was commissioned by the Authority in response to the claimants’ first damage notice in January 2007 and another was requested by Mr Wilshaw when he was first instructed.

44. Mulpan was regarded by both geotechnical experts as a reliable basis for the general estimation of movement in the vicinity of Wentworth Woodhouse occurring at or about the time of mining using longwall methods. It should be appreciated that the Mulpan programme, like the SEH before it, is not a tool for measuring subsidence which has occurred, but rather for predicting whether, and to what extent, subsidence attributable to mining ought to have occurred. Armed with this prediction it is then possible to assess whether subsidence actually evidenced on the ground is likely to be mining related, or must have had some alternative cause.

45. Although based on sound mining principles and experience these mathematical methods of predicting the surface effects of deep mining are acknowledged to have their limitations. In particular as Mulpan is based on case studies of longwall mining it does not purport to predict movement as a result of opencast or partial extraction techniques; nor does it predict the effect of mining induced fault reactivation. In addition as the case studies on which Mulpan is based date from the 1980s and earlier, the programme could not take account of any large scale regional ground movements such as are said by the claimants to have occurred in South Yorkshire since the cessation of deep mining in the 1990s. Mining in the vicinity of Wentworth Woodhouse

46. Extensive coal mining to depths in excess of 300 metres took place in the general locality of Wentworth Woodhouse between 1923 and 1979, with the last mining in the immediate vicinity ending in 1964. Seven different coal seams were mined from different collieries, in part by the opencast method and in part by a variety of deep mining techniques. The location and progress of the workings is shown in detail on seam abandonment plans prepared by the NCB or its predecessors and now held by the Coal Authority. These have enabled the main details of the relevant workings to be substantially agreed.

47. In order of their descending depth below the surface the seven worked seams mined in the immediate vicinity and their different modes of working are summarised in the following table: Seam Dates of working depth below ground level Seam height Mining technique Barnsley 1947-1948 Up to 22m 2m Opencast 1951-1953 Up to 30m Pillar and stall Swallow Wood 1961-1964 60-67m 1.2m Longwall Lidgett 1963-1964 75-95m 1.51m Longwall Top Fenton 1950-1962 210-215m 0.8m Longwall Parkgate 1923-1925 1935-1959 205-270m 1.5m Longwall and room and pillar Thorncliffe 1946-1948 230-235m 0.8m Longwall Silkstone 1961-1963 296-310m 1m Longwall

48. It is relevant to say a little more about two of these seams, the Barnsley seam, which is the closest to the surface of all seven worked seams, and the Parkgate seam, which is considerably deeper and was the only seam worked in the immediate vicinity of Wentworth Woodhouse before nationalisation in 1947. The Barnsley seam

49. The Barnsley seam is the shallowest seam worked in the Wentworth area, and is found only on the south side of the Wentworth Fault. It outcropped close to the surface immediately south of the terrace wall and from April 1946 until August 1948 coal was extracted from it by opencast mining in the area to the front of the camellia house and on both sides of the terrace wall (though not beneath it) as well as in the formal gardens to within about 150 metres of the west front of the main house. The recently nationalised NCB is said to have been given personal instructions by Emmanuel Shinwell, the Minister of Fuel and Power, to dig “up to the back door” of the house; as a result the formal gardens became part of what was reputed to be the largest open cast mine in Britain. We were able to view aerial photographs of the open cast workings during our site visit.

50. The opencast workings were restored by 1948 but extraction from the Barnsley seam resumed in 1951. This time the workings were below ground at a depth of about 30 metres (although they may have been shallower in the vicinity of the camellia house), and the pillar and stall technique was employed. The subsequent abandonment plan shows a densely chequered warren of tunnels extending in some places to within about 50 metres of the west front of the mansion. The workings encroached much more closely on the camellia house, entirely surrounding it so that it appears on the abandonment plan as if marooned on a tiny island of solid ground. Moving north the Barnsley workings extended almost to the wall of the stable block, where they encountered the line of the Wentworth fault and abruptly ceased. The Parkgate seam

51. The Parkgate seam is critical to the claimant’s case and lies beneath the site at a much greater depth than the Barnsley seam. It was mined to the north of the Wentworth fault using both the longwall and the room and pillar techniques at a depth of 200 metres below the surface and to the south of the fault at a depth of 240 metres. The abandonment plan shows three or four distinct phases of the workings.

52. Mining of the Parkgate seam advanced from the Elsecar colliery some miles to the north east of Wentworth. In 1922 and 1923 the longwall method was used to extract coal from the seam to the north and north east of the stable block and of the mansion itself to within about 150 metres of the north tower. It is assumed that longwall mining was halted at that distance from the house out of concern by Earl Fitzwilliam to protect his family home.

53. In 1924 the more conservative room and pillar method was employed to mine t he Parkgate seam in an area directly beneath the entirety of the stable block and to the west and north-west of the mansion, coming to within about 100 metres of the northern end of the west wing. A chevron pattern was adopted under the stable block and the abandonment plan shows the workings angling towards the mansion in long chambers dug from central access tunnels.

54. In 1925 a similar pattern of working took place to the east of the mansion below the gardens, with the same arrangement of alternating areas of extraction and support running to within about 100 metres of the east front; these workings terminated in a short section of much narrower intercommunicating tunnels. The dimensions of the worked panels were very similar below the stable block and to the east of the mansion, the panels being about 20 to 22 metres wide and progressing in long rooms separated from each other by solid blocks of coal of the same dimensions; the length of these rooms varied and was not the subject of specific evidence, but appears from the abandonment plans to have been as little as 60 to 80 metres in some locations and as much as 300 metres in others.

55. Finally, between 1927 and 1939 the Parkgate seam was worked to the south and south west of the mansion, immediately beneath the terrace wall and the camellia house. These workings were by the pillar and stall method below the camellia house and approaching the western end of the terrace wall, but predominantly by the room and pillar technique towards the eastern end of the wall.

56. Once again it is assumed that the adoption of these more conservative, partial extraction techniques in the mining of the Parkgate seam closest to the mansion was intended to preserve it from damage.

57. Three further important features of the Parkgate seam should be noted. First, to the east of the mansion it lies directly above the later workings in the Thorncliffe (1946) and Silkstone (1962) seams (both mined by the longwall technique). The Thornclife seam is only about 25 metres below Parkgate, but Silkstone is much deeper. Secondly, the abandonment plans show a section through the seam indicating that above and below the coal itself there were strata of “inf. coal” (which we take to mean “inferior coal”), “clod” and “dirt”, referred to elsewhere as “top softs” and “bottom softs” or as “seatearth”. It was explained that this is softer rock which includes remnants of the soil and organic matter which once supported the vegetation from which the coal strata were created. Thirdly, and significantly for the claimants’ case, the Parkgate seam was the only seam worked directly beneath the stable block.

58. The impact of the Wentworth fault on the workings has been a continuing subject of concern. We were shown correspondence in 1960 between agents for the Fitzwilliam Estate and the National Coal Board. Concern about ongoing movement prompted Mr Bedford, the Area Land and Minerals Officer for the Board, to comment that: “The amount of movement is surprising and I agree that the Parkgate pillars were inadequate and the recent Barnsley workings have set up movement on the fault plain (sic) which may continue for some considerable time”. It is not clear whether the inadequate Parkgate pillars were those created in the areas worked by the pillar and stall technique or by the earlier room and pillar workings. Un-mined areas

59. No mining took place at any time directly beneath the mansion itself (nor beneath the adjacent village of Wentworth). The Fitzwilliam family had been the principal beneficiaries of mining under their estate, but the change from aristocratic to public ownership in 1947 brought intensified activity in the immediate vicinity and led to the complete encirclement of their magnificent home both at the surface and underground. When the abandonment plans are consolidated they show Wentworth Woodhouse surrounded on all sides by mine workings, in and under the garden, and beneath the terrace wall, the camellia house and the stable block, but not below the mansion which alone sits on an island of solid ground. Record of historic mining subsidence claims

60. A series of claims for compensation for damage to Wentworth Woodhouse caused by mining subsidence have been made in the past by the Fitzwilliams and by the local authority on behalf of the Lady Mabel College. A large number of these claims were met by the Coal Authority’s predecessors. The relevant records of claims and associated correspondence are now held by the Coal Authority and the frequency of these has been analysed by Arup on behalf of the claimants. Although the general chronology of claims is relied on by both parties and is not in dispute, care must be taken not to equate correspondence concerning damage claims with evidence of recent damage, as it is clear to us from perusing the correspondence that some claims were dealt with at a leisurely pace and generated correspondence over a considerable period.

61. The earliest claim made to the National Coal Board appears to have been in 1950 and there were regular claims and related correspondence continued throughout the period in which the College operated from Wentworth Woodhouse. From the mid-1950s until the mid-1970s correspondence in relation to the mansion and the stable block intensified, with claims being recorded in each location. After a lull between about 1975 and 1982, first a trickle and then a spate of further exchanges took place concerning the mansion in the mid to late 1980s. Damage claims in relation to the stable block reduced after about 1974, but correspondence continued over about the next 15 years.

62. Masonry ornaments and monumental baskets of fruit on the roof of the camellia house were removed as a precaution in 1961 when very bad cracks first began to appear in the building. Claims in respect of damage to that building were concentrated in the early to mid-1960s, with eight claims in about seven years. Four further claims or items of correspondence concerning the condition of the building were received during the 1980s, the last in 1987.

63. Damage claims were also submitted in respect of the terrace wall, the first in September 1961; gaps created in the wall were fenced off in 1963 when subsidence at the wall was said still to be active; a further formal notice was given in 1976 and correspondence continued until 1986. Claims were also made in relation to the grounds and structures within them between the mid-1960s and the mid-1980s.

64. In general it appears that these historic claims for compensation were not contentious and were settled amicably between the NCB and the West Riding County Council or the Wentworth Estate. Not insubstantial sums were frequently paid out. Details of the last claims settled by agreement were provided by Mr Cammack. £12,000 was paid towards works of repair to damaged brickwork and stonework in the mansion between 1984 and 1988, and a further £3,000 was spent in September 1985 on repairs to an underground tunnel or cellar beneath the building. A payment of £2,316 was made as a contribution towards the repair of damage in the College gymnasium, located in the stable block, in September 1987. £2,329 was paid as a contribution towards the repair of the ha-ha wall, also in 1987.

65. In July 1986 a claim in relation to the camellia house was made by the Wentworth Estate, whose agent was “certain that recent damage has occurred”. A joint inspection revealed the camellia house to be in a bad state of repair and dilapidated with evidence of vandalism. Nevertheless, the claim was subsequently rejected on the grounds that no recent mine workings had taken place in the vicinity of the property which could have been responsible for the damage.

66. No further payments have been made for damage at Wentworth Woodhouse since 1988, and Professor Haydon-Baillie (no stranger to litigation) appears to have submitted no claims during the period of his ownership from 1988 to 1999.

67. The absence of later claims may have been unexpected. The NCB had certainly anticipated further liability, despite the absence of recent mining activity in the area. In December 1986 its area estates manager for South Yorkshire estimated a repair liability of £46,000 for the house and a further £20,000 for the stable block, an assessment which appears to have been accepted by the Board’s Deputy Accountant. A file note in June 1987 referred to recent movement apparent on the east elevation with large courses of stone displaced and a stone fractured. Internal correspondence in 1987 acknowledged that liability for damage to the main structure could not be finalised because of “continued slight movement along the fault line”. A review in 1988 recorded that “this property sits on a nest of geological faults and was damaged in 1986; movement does occur from time to time.”

68. Mr Cammack also told us that there are over 680 domestic and 50 commercial properties within a 2 km (1.2 mile) radius of Wentworth Woodhouse. Since 1990 claims have been made for compensation for damage to ten properties within that area. Two of these claims were settled by a payment from the Coal Authority in the early 1990s (both relating to a fissure which opened in the same area of woodland). Eight further claims (five of which related to built structures) were rejected. Since 1996 the only claims in the locality received by the Coal Authority have been the claims in relation to the damage to Wentworth Woodhouse which are the subject of this reference, and a claim by Yorkshire Water (advised by Arup) in respect of damage to the Hoober Reservoir which was rejected by the Coal Authority in 1999 and was not pursued. The purpose of this part of Mr Cammack’s evidence was obviously to invite the inference that an absence of damage claims meant an absence of ground movement. In that regard it is relevant to note, however, that a high proportion of the 730 properties within Mr Cammack’s chosen radius of Wentworth Woodhouse are likely to be in the village of Wentworth itself, beneath which no mining took place. Damage

69. The large scale extraction of coal by underground mining using total extraction methods invariably results in ground movement and often in surface deformation. Three varieties of ground movement were identified as relevant to Wentworth Woodhouse: subsidence, which is the vertical lowering of the surface of the ground; strain, which is differential horizontal displacement of the ground; and tilt, which is differential vertical displacement. There is no dispute that considerable damage has occurred to Wentworth Woodhouse in the past as a result of ground movement caused by mining, and the buildings all bear signs of substantial works of repair carried out in about the 1960s. The last recorded repair following an accepted subsidence claim was in 1988. The current dispute concerns damage of more recent origin.

70. Comprehensive surveys of the fabric of the structures at Wentworth Woodhouse may be required at a later date but it was agreed by the parties that at this stage in the claim it was necessary and proportionate to establish only whether or not there has been ongoing subsidence which might have been caused by mining. To enable that to be done further investigations have been concentrated on four specific locations rather than across the buildings and estate as a whole. The areas under scrutiny have been:

1. The north tower including the north quadrant on the east front of the mansion

2. A line of damage through the east front of the mansion, the north wing and an internal courtyard known as Basin Court which is said by the claimants to follow the line of the Wentworth fault

3. The south terrace wall

4. The camellia house