UPPER TRIBUNAL (LANDS CHAMBER)

UT Neutral citation number: [2010] UKUT 193 (LC)

LT Case Number: LCA/121/2009

 

                            TRIBUNALS, COURTS AND ENFORCEMENT ACT 2007

 

COMPENSATION – mining subsidence – dwellinghouse suffering damage – whether damage caused by mining subsidence – held that respondent had shown that it was not – Coal Mining Subsidence Act 1991, s40

 

 

                                 IN THE MATTER OF A NOTICE OF REFERENCE

 

 

BETWEEN                                     VALERIE EDNA WOOD                                   Claimant

                                                                           and

 

                                                       THE COAL AUTHORITY                             Respondent

 

 

                                                         Re: 48 Stocksfield Avenue

                                                                Fenham

                                                                Newcastle upon Tyne

                                                                NE5 2EX

 

 

                                                         Before: N J Rose FRICS

 

 

        Sitting at Newcastle Social Security and Child Support Agency, Manor View House,

                          Kings Manor, Newcastle upon Tyne, NE1 6PA on 11 May 2010

                    and at Asylum and Immigration Chambers, Kings Court, Royal Quays,

                                           Earl Grey Way, North Shields, NE29 6AR

                                                              on 12-14 May 2010

 

 

 

 

 

Susan Lindsey, instructed by Beachcroft LLP, solicitors of Birmingham, for the claimant

Dominique Rawley, instructed by DLA Piper UK LLP, solicitors of Sheffield, for the respondent

 

 

 

 

The following case is referred to in this decision:

 

Burton and Burton v National Coal Board, 22 April 1982, REF/122/179, unreported

 

The following further cases were cited in argument:

 

Coal Authority v Davidson & Davidson [2008] EWHC 2180 (TCC)

AXA Insurance UK Plc v Cunningham Lindsey UK [2007] EWHC 3023 (TCC)

 

                                                                    DECISION

Introduction

1.           This is a reference under sections 40(1) and 40(3) at the Coal Mining Subsidence Act 1991 (the 1991 Act) for determination of the question whether damage suffered by a dwellinghouse known as 48 Stocksfield Avenue, Fenham, Newcastle Upon Tyne, NE5 2EX (No.48) was subsidence damage caused by the withdrawal of support in connection with coal mining operations.  In the event of a ruling in favour of the claimant, Ms Valerie Edna Wood, the parties will seek to agree the form of the order to be made, in default of which the matter will be referred back for determination by the Tribunal. 

2.           Ms Susan Lindsey of counsel appeared for the claimant.  She called factual evidence from Mr Y Patel, a chartered civil engineer employed as a technical manager in the National Subsidence Unit of Crawford and Company (Crawfords), loss adjusters, who were appointed by the claimant’s insurers to investigate a claim notified by the claimant in April 2004 in respect of damage to No.48.   Ms Lindsey also called evidence from three expert witnesses.  They were Mr N W Jackson Eur Ing, FIME, CEng, practising as N W Jackson International Management and Mining Consultant in Seaton Sluice, Northumberland; Mr J V Ellis BSc, FNEIMME, a consultant mine geologist and Mr R J Evans BSc, CEng, MICE, MIStructE, a partner in Messrs R J Evans Knowles and Partners, chartered civil and structural engineers of South Yardley, Birmingham.  Ms Lindsey also produced a witness statement from the claimant, which was not challenged.

3.           Counsel for the respondent Coal Authority, Ms Dominique Rawley, called one expert witness, Mr J P Ottaway MICE, a director of WYG Engineering based at his firm’s Nottingham office. 

Facts

4.           From the evidence and agreed statements I find the following facts.  No.48 is located in an area between Fenham and Benwell in western Newcastle upon Tyne.  Stocksfield Avenue is accessible from the B1306 which leads to the A186, a main route from the A1 into the city centre.  It is a brick built semi-detached house with a pitched tiled roof.  Planning consent for its construction was granted in 1957 and it was built between 1957 and 1959.  There is an attached single storey garage at the left hand side.  There are garden areas at the front and left hand side of the house and at the rear is a paved garden, sloping downwards slightly away from the house.

5.           The ground floor accommodation comprises a hall and wc, leading to a front living room, a rear dining room and kitchen.  On the first floor there are two bedrooms at the front and a bedroom and a bathroom at the rear.

6.           No.48 is one of a block of four semi-detached houses which front onto Stocksfield Avenue, and whose rear gardens are bounded by 20 Benwell Hill Road and 16 Rothley Avenue.  The housing estate surrounding No.48 was mainly built around 1930 but the twelve houses, 10-16 Rothley Avenue, 42-48 Stocksfield Avenue and 21-26 Benwell Hill Road, were built as an infill development in about 1958.

7.           The land to the west of this block of houses is occupied by Silverhill School and Stocksfield Primary School, built between 1957 and 1961.  As one approaches the site from the primary school up Benwell Hill Road, the road rises in level towards the infill block of twelve houses.  This rise in topography is mirrored in the layout of Rothley Avenue to the north of the infill block, where the road falls steeply away from Stocksfield Avenue.  The infilled block of houses is therefore constructed on a natural hollow within the natural topography. 

8.           The boundary wall between this block of houses and the school grounds to the west of the site is a small retaining wall approximately 1-2m in height.  There are brick buttresses constructed at regular intervals along the length of this wall.  The date of construction of the buttresses is not known, but they either predated or were concurrent with the construction of the security fence to the school which steps around the buttresses. 

9.           The claimant moved into No.48 in January 1990 with her fiancé, Mr Paul Myers, who sadly died in 1994.  In about April 2003 she first noticed a crack over the kitchen window in the wall and ceiling.  The crack soon became worse, widening and extending from above the kitchen window to the wall dividing the kitchen and dining room.  The blind kept falling off the wall.  Cracks then appeared around the patio doors in the dining room and along the wall separating No.48 from No.46.  Damage also occurred in the back bedroom above the dining room.  Cracks appeared around the rear bedroom window from the top right hand corner up to the ceiling and from the bottom right corner to the skirting board.  The curtain rail also kept falling off, due to movement of the fittings.  Cracking also appeared under the window on the stairs.  Generally there were signs of movement throughout No.48, the wallpaper puckered and the carpet moved away from the walls, so that floorboards were visible. 

10.        The cracking in the kitchen continued to deteriorate.  After noticing damage in the dining room and rear bedroom, the claimant notified her insurers, Northern Rock, who appointed Crawfords to investigate.  Mr Stephen Duffield FRICS, FCILA from Crawfords inspected the property on 7 April 2004.  He reported to Northern Rock on 8 April 2004 as follows:

“Discussion

At this stage the cause of the movement is unclear.  We suspect that the drains are leaking particularly as problems with blockages have been experienced in the recent past.  However there are no drains along the rear elevation which appears to be suffering the most movement.  There are sign of lintel failure to a number of windows as a result of UPVC replacement units inserted about five years ago but this does not explain the cracking seen in the dining room and the lower levels on the gable wall.  The rear elevation wall leans outwards from ground level and has been repointed although prior to the insured’s ownership.  Generally the degree of damage internally is not reflected in the external brick wall.

Recommendations

We will arrange a site investigation including drain testing as well as a period of monitoring.  Studs have already been set in place and initial readings taken.  Monitoring is a useful diagnostic tool.  Cracks that open and close are generally indicative of clay shrinkage problems, whilst cracks that open episodically, without closing, are indicators of water problems (leaking drains, water services etc) or possibly heave.  It also allows us to tell when movement has stopped, and when repairs can be implemented.  Readings will be taken at bi-monthly intervals to judge the efficacy of any drainage repairs.  When we are satisfied movement has stopped, the damage can be cosmetically repaired.  Monitoring is carried out in accordance with requirements of the Building Research Establishment.”

11.        On the day Mr Duffield produced his report, and on his instructions, Auger Solutions carried out a survey of the underground drainage system at No.48.  Auger reported to Mr Duffield on 21 April 2004.  They said that their drain survey had been in three parts.  Firstly, a CCTV survey of three lines of drains.  Secondly, a visual examination of the visible drainage and, thirdly, water pressure testing of one gulley at the rear of the property.  The reported conclusions were as follows:

“(a)   The results of the CCTV/inspection survey to this part of the system revealed no significant defects which would affect its operation during normal usage, however, it must be appreciated that as with all drainage systems, regular maintenance and upkeep is essential.  It should be periodically inspected in the future for any deterioration and kept free flowing/free of blockages.  Any damage noted during future inspections should be repaired immediately in accordance with current Building Regulations.

(b)     The cracking noted within the pipework is minor and unlikely to be allowing any escape of water, therefore any relining undertaken would be purely precautionary, however we do not feel that this is necessary at this time.”

12.        Under the heading “Limitations of Report” the author of the Auger report said:

“The lack of any significant defects within the main drainage line should not be regarded as a guarantee of watertightness.  Defects may be encountered upon exposure of inaccessible branches and gullies etc.”

13.        On 24 June 2004 Mr Duffield submitted an addendum technical report to Northern Rock, interpreting the results of the investigations to date.  He explained that a trial hole had been excavated in the rear garden close to the rear wall ofNo.48, but this did not identify any cause of movement.  He added:

“The foundation is shallow by modern standards and rests on a moist stiff clay subsoil which becomes darker with depth.  No tree roots were found and the bearing pressure is adequate.”

14.        Under “Discussion” Mr Duffield said

“At this stage the cause of the movement remains unclear.  The drains are not leaking and no significant defects were found.  The foundations are acceptable for the imposed loading.  There are signs of lintel failure to a number of windows as a result of UPVC replacement units inserted about five years ago but this does not explain the cracking seen in the dining room and lower levels on the gable wall.  The rear elevation wall leans outwards from ground level and has been re-pointed although prior to the Insured’s ownership.  Generally the degree of damage internally is not reflected in the external brickwork. 

Recommendation

In the circumstances monitoring of the cracks will continue and we will also instigate level monitoring to determine whether the building is continuing to move.  Provided stability can be established repair of the superstructure can be undertaken.”

15.        Readings were taken from the crack monitoring studs between April 2004 and March 2009.  Level monitoring was carried out from July 2004 until March 2009. 

16.        In January 2005 the insurance claim was passed by Mr Duffield to his colleague at Crawfords, Mr Patel, who inspected No.48 on 3 February 2005.  He was told that the owner of the adjoining property, No.46, had advised the claimant that some drilling in his front garden would be carried out by the respondent.  This was because there were cracks throughout No.46 and it was thought that it could be due to coal mining subsidence.  Because the adjoining owner had initiated a claim against the respondent, Mr Patel considered it was appropriate to ask the claimant to serve a Damage Notice on the respondent, which she did on 18 May 2005. 

17.        On the respondent’s instructions White Young Green (WYG) had conducted a site investigation at 46 Stocksfield Avenue in April 2005.  They conducted a further investigation, of Nos.48 and 42, between 30 August and 1 September 2005.  The number and location of the boreholes was determined by WYG in conjunction with the respondent.  A borehole was drilled in the front garden of No.46 and two further boreholes were drilled in the rear gardens of Nos.42 and 48.  All boreholes were drilled to a depth of approximately 10m below ground level using rotary coring methods.

18.        A Landmark “Envirocheck” report was prepared on 1 June 2005 on the instructions of WYG.  The historical mapping provided with the report showed that the group of 12 houses of which No.48 formed part was constructed after the remainder of the estate.  The 1961 1:2,500 Ordnance Survey plan showed that a small structure formerly in the south eastern corner of the plot, whose nature and use were unknown, had been demolished and the adjacent Silverhill S chool and the current group of houses had been constructed.  The O.S. mapping showed that it had remained the same since 1961.

19.        Following these investigations the respondent denied liability for the damage to No.48 in a letter dated 29 November 2005, for the following reasons:

“The last coal mining that could have affected the property was prior to 1947 as you may or may not be aware any damage resultant from those workings would have become evident at that time or a short time thereafter.  With regard to the possibility of damage arising from the presence of shallow unrecorded coal workings, this has been discounted following recent borehole investigations that encountered an intact coal seam, but no voids or broken ground.  It is concluded that having encountered 3.8m of made ground, fill and clay above coal measure strata, damage evident at the property is as a result of ongoing compaction of these unconsolidated materials.”

20.        In January 2006, on instructions from the respondent, Aimrange (NE) Limited carried out a CCTV survey and hydrostatic test of the drain runs.  The respondent sent a copy of the results to the claimant on 22 February 2006.  The accompanying letter said:

“The survey revealed fractures in the drain runs between MH1 and MH2, MH1 and RWG situated at the front corner and MH1 and the buried MH at the front elevation.  Hydrostatic tests carried out along each drain run reveal that MH1 to MH2 was not watertight, neither was MH1 to RWG.  I therefore conclude that the drains are in poor condition and leak and may be a contributory factor towards the differential settlement that is evident around the property.  I can only uphold the Authority’s previous rejection of the claim and regret that I cannot be of further assistance in this matter.”

21.        Mr Patel replied to the respondent on 27 March 2006.  He said:

“We refer to your letter dated 22 February 2006, sent to the property owner, Mrs V E Wood. 

We have examined the drainage survey results as provided by Aimrange.  As you are aware, the slight leak from the drainage system is from the front left hand section of the property and the damage to the property is at the rear.  On this basis, we reject your conclusion that the damage to the property is associated with leaking drains.  We kindly ask you to reconsider your position on liability for the damage.

We are aware that you have carried out extensive site investigations at the property and we would welcome a copy of these findings to progress further.  Please provide a copy of the site investigation information to our main office address.”

22.        On 3 April 2006 Mr King of the respondent replied as follows:

“I note your comments regarding my conclusions in respect of leaking drains at the property and the fact that these are remote from the damage.  I wished only to make the point that the state of the drains is not helpful in this matter. 

The Authority’s rejection of your claim is based on recorded borehole information.  Broken ground, bed separation or voids were not identified at shallow depth beneath the rear of the property.  However, unconsolidated deposits of ‘fill and clay’ were recorded to a depth of 3.8m.  I have enclosed a copy of Messrs White Young Green’s report compiled on behalf of the Authority for your perusal.”

23.        Mr Patel then sought advice from Mr G Phipps of SP Property Services, a coal mining subsidence expert.  Mr Phipps reported to Mr Patel on 10 July 2006 in the following terms:

“I have now received various reports/information regarding the above property as listed below (and as attached):-

a.           Standard coal mining report

b.           Claims history report

c.           Envirosearch Residential Report

d.           Old maps extract dated 1864.

My initial thoughts after reviewing the paperwork are as follows:-

The dwelling and neighbouring properties are built off made ground.  The existence of made ground may relate to the extraction of coal from the surface pre 1872 (ie before records of mining had to be kept).  Coal is noted to outcrop in the area and the map dated 1864 indicates that quarrying was carried out in proximity.  There is an inference that the made ground may relate to historical tipping (pre 1958) carried out by Brydon Ropes (Ref White Young Green report).  Infilled ponds are known to exist in the locality but due to the depth of fill, we more readily suspect that mining extraction is a likely factor. 

Possible cause of movements

Ongoing long term resettlement of the site due to the nature of the fill material.  Any drainage defects will compound these effects although the drains apparently run to the side and front of the dwelling whereas movement appears to be focused to the rear.

Recommendation

A further set of monitoring readings are to be taken shortly and as such, evidence of further progressive movement can be assessed and review. 

I think there are grounds to go back to the Coal Authority and request that they re-consider liability for movement as it is our initial opinion that the damages may be related to coal mining extraction.  The CA ultimately have to prove that there is no link and the background research infers that mining is a factor for consideration even if the activity predates 1872.  Worth a letter in any event!  The damages to the drains may also be related to coal mining activity and long term movement of the fill material.”

24.        Mr Patel wrote again to the respondent on 17 August 2006.  He said that it was well known that No.48 was situated in an area where shallow coal mining had been carried out and that this was supported by the results of the investigations carried out by the respondent.  He asked for copies of any old records in the respondent’s possession relating to coal extraction below No.48.  On 18 August 2006 the respondent replied that they had no old records relating to shallow mining and they again denied that they had any liability under the 1991 Act.

25.        Fugro Engineering Services Limited carried out further investigations at No.48 at the request of the respondent in September 2008.  Three boreholes (WS1 to WS3) were sunk using the soil sampling (window) system to a maximum depth of 4.45m below ground level.  WS1 was in the front garden and the other two holes were in the rear garden.  In addition two trial pits (HETP1 close to the rear wall and HETP2 close to the front wall) were excavated by hand in the garden to depths of 0.82m and 1.20m below ground level respectively. 

26.        On 31 January 2009 Geol-Consultants Limited drilled two boreholes at No.48 on behalf of the claimant.  BH1, in the front garden, was dug to a depth of 24.08m and BH2B close to the back corner of the house, was 5.49m deep.  A further borehole in the front garden, BH2A, was abandoned.

27.        Auger carried out further investigations for the claimant at No.48 in August 2009 in an attempt to ascertain details of the foundations.  The work included lifting the suspended timber floor and drilling a hole into the concrete below.  In addition four trial holes were excavated.  Two of these (TH2 and TH3) were directly next to the party wall and TH1 was 600mm from the party wall.  TH4 was excavated in the rear living room adjacent to the kitchen.

28.        Damage notices have been served on the respondent in respect of Nos.42, 46 and 48 Stocksfield Avenue, but not No.44. 

29.        Plans are held in the Tyne and Wear Archive relating to a development at Benwell Hill Road and Stocksfield Avenue, on the opposite side of the road to No.48.  Notes made by a planning officer and attached to the plans, dated 2 July 1952, say:

“The site is near to the line of the High Main coal seam, and not far from an outcrop of ‘Burnout’.  A note should be put on the plan to the effect that, if necessary, special precautions will be taken with the foundations.”

30.        Multi-seam mining lies beneath No.48.  All the seams were worked prior to 1947.  Seams known as Brass Thill (K) and Harvey (N) were extracted by the pillar and stall method at depths of 120m and 165m respectively.  Bottom Busty (Q2) at 204m and Brockwell (S) at 226m were worked by total extraction mining methods, but the seams were abandoned in 1935 and it is not known whether all the coal has been extracted.  Main Seam F, which was worked in the area by pillar and stall mining, extended beneath No.48 at a depth of approximately 20m.  High Main Seam E extended at shallow depth beneath No.48.    

The expert evidence

31.        All four expert witnesses produced an expert report, together with one or more supplemental reports as more information became available.  The expert evidence was detailed, as was inevitable given the complex geology  and mining history of the area.  It was, however, distilled into a helpful Joint Statement which was signed by all four experts shortly before the hearing and summarised the main areas of agreement and disagreement between them.  It will be convenient to reproduce it at some length from this point in the decision until the end of paragraph 69.  

32.        It is agreed that the substantive damage to No.48 occurred in 2003/2004.  The current evidence by way of monitoring suggests that the building is currently stable.  It is agreed that the mechanism that resulted in the cracks was differential movement of the foundations between the front and rear, between the garage and main building structure and around the bay windows and that the maximum downward movement occurred at the rear. 

33.        It is agreed that the four deepest coal seams beneath No.48 were worked before 1947.  Unlike Mr Ottaway, Mr Jackson and Mr Ellis are of the view that whilst the plans of Bottom Busty (Q2) and Brockwell (S) are represented by cross hatching in mining plans lodged with the respondent, this does not mean all the coal has been extracted.  They consider that it is highly probable that some pillars and remnant pillars of coal were left in situ.  It is for this reason that Mr Jackson and Mr Ellis dispute the statement that all subsidence would have ceased shortly after the extraction, as subsequent collapse of the pillars could have caused subsidence many years after extraction had ceased.

34.        It is agreed that No.48 is founded on made ground, but there is disagreement about the collapse of made ground in 2003.  Mr Ottaway is of the view that water escaping from the underground drainage and water percolating from the surface are likely causes of the subsidence.  Mr Evans is of the view that the only significant defects in the underground drainage were found at the front in a connection from a rainwater gully to a manhole and that these are too remote from the rear for any water that might have escaped to have been causative.  (In cross examination Mr Evans accepted that he had not noticed that Aimrange had reported that there was a crack in the main drainage run beneath the garage which was leaking fast).

35.        It is agreed that the made ground consists predominantly of clay.  Mr Ottaway is of the view that the recorded SPT (Standard Penetration Test) results of between 1 and 4 suggest that the soil has a shear strength of about 26kN/m² and that soil of this strength can be described as soft.  Mr Evans is of the view that despite any shear strength the soil might have, it has supported the building for forty-four years and therefore that the shear strength is adequate.

36.        There is disagreement about the thickness of the made ground and the depth at which it interfaces with the underlying clay.  Mr Ottaway is of the view that the made ground at the rear extends to a depth of at least 2m.  Mr Ellis is of the view that the findings from the Fugro investigation show that in one location (WS2) it extends to a depth of 1.2m and in another that it extends to a depth of 1.9m;  Mr Evans agrees with Mr Ellis.

37.        There is a dispute as to whether the foundations were founded on suitable strata.  Mr Ottaway is of the view that they were not.  Mr Evans is of the view, based on the benefit of forty-four years of hindsight, that they were. 

38.        There is a dispute as to whether the soil and made ground below No.48 is of a type that would be more affected by water inundation than any other type of cohesive soil.  Mr Ottaway is of the view that it would be particularly susceptible to water inundation.  Mr Evans is of the view that there is no evidence to show that the soil below the property would be more susceptible to water inundation than any other type of cohesive soil.  Mr Evans is also of the view that in any event there is no evidence of the soil below the property having been affected by water inundation.

39.        It is agreed that water was encountered in some of the boreholes drilled at No.48.

40.        It is agreed that the rapid movement that occurred in 2003, which resulted in the cracks, was caused by an external influence.

41.        There is a dispute as to whether water escaping from defects in the underground drainage could have caused settlement of the made ground at the rear.  Mr Ottaway is of the view that this is likely.  Mr Evans is of the view that the defective drainage is too remote from the rear for any water that might have escaped from it to have caused settlement at the rear.

42.        There is a dispute as to whether there are trees and/or other significant vegetation close to No.48.  Mr Ottaway is of the view that there is vegetation close enough to have caused damage to the bay window at the front of the property.  Mr Evans is of the view that although there are shrubs in the rear and side gardens of the property these are far too remote to have had any influence on the soil below the building.  Mr Evans notes that no roots were recovered during any of the subsoil investigations.

43.        It is agreed that the underside of the foundation at about 0.8m below ground level is below the zone that would typically be affected by evaporation from the surface.

44.        It is agreed that water will have percolated downwards from the surface.  However the significance of this is not agreed.  Mr Ottoway is of the view that water percolating from the surface is a likely cause of settlement of the made ground.  Mr Evans is of the view, based on there not having been any significant settlement of the foundations during the 44 years preceding the damage in 2003/2004, that this was not the cause of the damage.

45.        There is a dispute about the significance of the retaining wall to the west of No.48.  Mr Ottaway is of the view that the wall has suffered movement, damage and subsequent repair and that this is indicative of instability and movement in the made ground, which is retained by the wall.  Mr Evans is of the view that there is no evidence to show that the retaining wall has suffered any material movement and in any event it is too remote from the building for any movement that it might have suffered to have been causative.

46.        There is a dispute as to the form of the foundations as constructed.  Mr Ottaway is of the view that the foundations are strip footings.  Mr Evans is of the view, based on the findings from a subsoil investigation carried out below the dining room floor (at the rear), that the form of the foundation is a raft.

47.        There is a dispute as to the adequacy of the foundations.  Mr Ottaway is of the view that the foundations were neither compliant with the design drawings nor adequate for the ground on which they were founded.  Mr Evans is of the view that the foundations were constructed to the approval of the Building Inspector, who would typically have had knowledge of the local ground conditions, and therefore they can be considered as being adequate.  Mr Evans is of the view that as the foundations performed satisfactorily for 44 years they have been shown to be adequate.

48.        It is agreed that the layout of the underground drainage is as stated in the Aimrange report dated 17 January 2006 and that the condition at that time was as stated in the same report.  It is agreed that Aimrange reported defects in the underground drainage.  Mr Ottaway is of the view that these were a likely source of water to enter the ground.  Mr Evans is of the view that the only significant defects recorded by Aimrange were in a run of pipework from a rainwater gully at the front to a manhole in the driveway, and that because these defects were holes in the top half of the pipe, they would not have allowed significant quantities of water (if any at all) to escape during normal flow conditions.

49.        There is a dispute as to whether there is a causal link between the damage and the defects in the drainage.  Mr Ottaway is of the view that this is likely.  Mr Evans is of the view that it is highly unlikely. 

High Main Seam E

50.        It is agreed that the High Main Seam E extends below number 48.  There is a dispute as to the position of the outcrop of the High Main Seam E.  Mr Ottaway is of the view that it outcrops below No.48.  Mr Jackson and Mr Ellis are of the view that it outcrops to the north-west of No.48.  (Note.  An outcrop is the face of a rock type where it emerges at ground level or at the interface with superficial deposits).  There is a dispute as to whether the High Main Seam (E) has been worked below No.48.  Mr Ottaway is of the view that it has not been worked.  Mr Jackson and Mr Ellis are of the view that it has been worked.

51.        There is a dispute as to whether the AEG borehole investigations for WYG are supportive of the High Main Seam (E) having been worked below No.48.  Mr Ottaway is of the view that they are not supportive.  The borehole logs indicate Glacial Till sitting directly on the exposed and eroded coal outcrop with no evidence of any workings.  Mr Jackson and Mr Ellis are of the view that the borehole results are consistent with the view that the High Main Seam (E) has been worked below No.48.   

52.        There is a dispute as to whether the Fugro investigations are supportive of the High Main Seam (E) having been worked below No.48.  Mr Ottaway considers they are not supportive. There is no evidence of collapse of ground above the High Main Seam (E).  The Fugro boreholes show Glacial Till sitting directly on the exposed and eroded coal outcrop.  Mr Jackson and Mr Ellis are of the view that they are consistent with the seam having been worked in a similar manner to that described in the “Carruther’s Burnout paper” ie. leaving the bottom poorer quality part of the seam.  The coal thicknesses recorded are not consistent with the coal seam having been eroded.

53.        There is a dispute as to whether the evidence is supportive of the High Main Seam (E) having been worked below No.48.  Mr Ottaway is of the view that it is not supportive because the evidence is not site specific.  Mr Jackson and Mr Ellis are of the view that all of the evidence, when taken together, is supportive of the High Main Seam (E) having been worked below No.48.

Main Seam F

54.        It is agreed that the Main Seam F has been worked in the Fenham area and that the investigations carried out by Ian Farmer Associates on the nearby school site are supportive of the Main Seam F having been worked at that site.  It is agreed that the Ian Farmer findings are indicative of pillar and stall mining of the Main Seam.  It is agreed that the geological evidence suggests that the Main Seam F extends below No.48. 

55.        There is a dispute as to whether the evidence is supportive of the Main Seam F having been worked below No.48.  Mr Ottaway is of the view that the evidence is inconsistent and inconclusive.  Mr Jackson and Mr Ellis are of the view that all available evidence indicates the probability of the seam having been worked.  The 1807 report commissioned for the sinking of the Fenham colliery referred to ancient reports that it was wholly or partially extracted throughout the Fenham area.  The investigations at the school site nearby and the borehole drilled in January 2009 show that these workings extended beneath No.48.

56.        There is a dispute as to whether the findings from the site investigation boreholes undertaken during August and September 2005 are supportive of the Main Seam F having been worked below No.48.  Mr Ottaway considers that there is no evidence of this.  Mr Ellis is of the view that boreholes 02A and 03A were drilled open-hole to a depth of 11.0m and 11.3m and is of the view that the findings do not give any evidence to support or deny the working of Main Seam F below No.48.  Mr Ellis also notes that highly fractured strata with weathered joints and bedding were encountered in borehole 05 and loss of flush occurred at 8.6m in strata that would naturally have low permeability/porosity.  The findings indicate ‘relaxing’ of the strata, which is indicative of subsidence at greater depth;  however, it is not proven that this is in seam F.  It is agreed that the Fugro investigation did not provide any evidence of the Main Seam F having been worked below No.48 because it only extended to a depth of 4m.

57.        There is a dispute as to whether the investigations carried out in January 2009 are supportive of the Main Seam F having been worked below No.48.  Mr Ottaway believes the evidence is inconsistent and inconclusive.  Mr Jackson and Mr Ellis are of the view that they are supportive and base their view on the sudden drop of the drilling rods at a depth of 23.5m indicating a void (open mine workings) about 1m deep.

58.        It is agreed that there is the potential for there to be unrecorded workings in the High Main Seam E and Main Seam F in the Fenham area.  Mr Ottaway states that this is a generic conclusion and not specific to No.48.  Mr Jackson states that pillar and stall workings can (and do) collapse decades after mining has ceased.  Mr Ottaway did not make any comment.  (In cross examination, he accepted that pillar and stall mining collapses can be independent of time).

59.        There is a dispute as to the effects of the collapse of pillar and stall workings.  Mr Ottaway is of the view that the collapse of pillar and stall workings can result in crown holes at the surface but that there is no evidence of this at No.48.  Mr Ellis and Mr Jackson are of the view that the collapse of pillar and stall workings can result in either crown holes or more widespread subsidence (areal subsidence) and are also of the view that the latter is a likely cause of the damage at No.48.  (In cross examination Mr Ottaway accepted that collapse of workings can result in areal subsidence, but he did not agree that it had occurred below No.48).

60.        It is agreed that the effect of subsidence is loss of support to building foundations. 

61.        In relation to the question:  what are the effects of subsidence on the overlying coal measure strata?  Mr Ottaway considers the question to be too general.  Mr Ellis is of the view that this is to relax the strata, which may influence the environmental conditions resulting in a potential for collapse at higher level.

62.        In relation to the question: what are the effects of subsidence on the superficial deposits?  Mr Ellis gave his view that this depends on the nature of the subsidence.  Crown holes result in a collapse of the clays above to an angle of rest of about 45 degrees.  Subsidence can result in tensional forces being applied to the clay in both horizontal and vertical directions resulting in partings within the clay and possible collapse.  This makes the clay susceptible to inundation by water making formerly firm clay into softer clay.

Burnout

63.        It is agreed that a definition of ‘Burnout’ is “the effects of an in-seam fire”.  Both Mr Jackson and Mr Ellis are of the view that Burnout is evidence of mining and note that Burnout is a description given by Mr R G Carruthers in his paper “Burnt outcrop associated with the High Main coal in Newcastle-upon Tyne”, which refers to a local effect of burning of the coal seam at Fenham.

64.        Mr Ottaway, Mr Jackson and Mr Ellis stated the following in relation to how Burnout can be identified:  Mr Ottaway – Where in situ coal-measure strata (mudstones and siltstones) show signs of intense heat indicated by reddening;  Mr Jackson – by an examination of the strata above the seam in which the Burnout occurred.  Mr Ellis – indicated by the strata in situ showing signs of having been burnt.

65.        In relation to whether there is evidence of Burnout in the Fenham area Mr Ottaway, Mr Jackson and Mr Ellis referred to the paper by Mr R G Carruthers which identified Burnout in the Fenham area.  There is a dispute as to whether there is evidence of Burnout below No.48.  Mr Ottaway considers that there is evidence of red shale being found as part of the made ground at the south part of the garden, and at some distance from the house, but that this is not evidence of Burnout.  Mr Jackson and Mr Ellis consider that their finding from hand-auger investigation demonstrates Burnout at shallow depth.

66.        It is agreed that there is made ground below the building and that this consists predominantly of clay from the locality.  It is agreed that neither the land below No.48 nor the surrounding area is a ‘land-fill site’.  It is further agreed that the underlying natural deposits are Glacial Till over Coal Measures.

67.        In relation to the differences between WYG’s final logs and AEG’s basic information, Mr Ottaway did not make any comment.  Mr Ellis is of the view that the AEG information gives a clearer indication of strata relaxation from the collapse of workings below. 

68.        It is agreed that there is evidence of ground water below No.48.

69.        It is agreed that fracturing of the strata and staining on the bedding planes could indicate that seams below No.48 have been worked and that subsidence has occurred.  However, Mr Ottaway is of the view that the subsidence occurred and was complete before the building at No.48 was constructed.

 

 

Conclusions

70.        Various investigations have been carried out in the vicinity of No.48 on the instructions of the parties, in an endeavour to assess the condition of the geology and the drains below ground level.  Significant efforts have also been made by the experts to obtain data which might shed light on the history of mine workings beneath No.48.  Despite these efforts it is apparent that much information which might have assisted in arriving at an accurate diagnosis of the cause of the damage is not available or, where it is available, is inconclusive.  I will give a number of examples of such deficiencies in the evidence. 

71.        Many mine plans do not form a complete or accurate record of mine workings.  Although it is agreed that the outcrop of High Main Seam E is in the vicinity of No.48, its precise location – which would be relevant to an interpretation of the nature and thickness of coal found in certain boreholes – is purely conjectural.  The accuracy of the first drain survey, carried out by Auger Solutions in April 2004, and which concluded that there were no significant drainage defects, is open to question.  They did not test the drains.  They failed to identify a drainage run leading from a rainwater gulley at the front of the house.  Their testing of the material in the trial hole at the rear of the house failed to identify the presence of made ground.  On the other hand, the conclusions which can be drawn from the condition of the drains as described in the Aimrange report in January 2006 are also limited.  Whilst it is agreed that the description of two drains as leaking badly was accurate at the time, the possibility that the condition of the drains had deteriorated since 2004 as a result of mining subsidence cannot be excluded.  In January 2009 Geol-Consultants Limited drilled the only borehole which reached the level of Main Seam F in the vicinity of No.48.  It encountered a void between 22.46m and 23.47m below ground level.  Mr Jackson explained that this borehole was an open-hole which, unlike a cored borehole, would not enable the driller to recover the broken strata.  He would have liked to have drilled several cored boreholes in order to establish beyond doubt whether there had been a collapse of Seam F workings beneath No.48.  His client had not instructed him to do so because of the cost involved.  Although precise level monitoring is generally a more reliable method of detecting mining subsidence than crack width monitoring, the level monitoring carried out at No.48 was not reliable, as it was not related to a remote datum. 

72.        The extent of the incomplete and inconsistent information that is available to them means that the experts in this case have had to form the best judgment they can in the light of the evidence that they have.  Mr Ellis described his task as being one of “balancing conflicting information”.  My task, in turn, is to balance the conflicting judgments of the experts.  Having done so, I have reached the conclusion that the judgment of Mr Ottaway is to be preferred to the opinions of the claimant’s experts.  There are two principal reasons why I accept Mr Ottaway’s opinion that the damage to No.48 did not result from the collapse of mine workings.  The first is that when such workings collapse the voids migrate upwards and form surface depressions, such as a crown hole formation or areal subsidence.  There is a patio to the rear of No.48 and a driveway, pavement and road to the front.  In my judgment one would have expected at least one of these features to have exhibited clear signs of surface depressions had any existed, but they did not. 

73.        Secondly, in nine boreholes drilled at or around No.48, not one encountered any coal measures (sandstone and/or mudstones), which one would expect to find above the coal.  The coal layer was found to be either directly below the made ground or directly below the boulder clay.  It follows, either that the coal was at the surface of the ground when the glacier or ice sheet deposited the boulder clay on top of it, or that it was at the surface when the made ground was deposited on top of it.  Mr Ottaway said, and I accept, that boulder clay would not have provided a roof support below which mining could take place.  I therefore conclude that the shallowest coal seam – High Main Seam E – has not been worked below No.48.  Notwithstanding the deficiencies in the overall evidence, I find that the combination of the absence of surface depressions and the absence of coal measures means, on the balance of probabilities, that coal mining subsidence was not responsible for the damage to No.48.

74.        I also accept Mr Ottaway’s opinion that the leaking drains were responsible for triggering collapse settlement of the unconsolidated made ground.  Considered overall, Mr Ottaway’s evidence on this topic appeared to me to be more objective than that of Mr Evans.  Mr Ottaway referred in his supplementary report dated 10 February 2001 to Building Research Establishment (BRE) Digest 274 by J A Charles and K S Watts entitled “Building on fill: geotechnical aspects”, which described the propensity of made ground to settle when affected by an inundation of water.  In my judgment Mr Evans’s subsequent selective choice of material from the report, in an attempt to discredit its conclusions, detracted from the overall persuasiveness of his evidence.

75.        Section 40(2) of the 1991 Act provides that

“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 Corporation to show that the damage is not subsidence damage.”

76.        Ms Lindsey submitted that the threshold for the section to apply was not high.  Ms Rawley stated in opening that the claimant had not adduced sufficient evidence to activate the provisions of section 40, but she did not elaborate.  I am satisfied that the wording of section 40(2), namely that circumstances are such as to indicate that the damage may be subsidence damage (emphasis added), is such that a limited amount of evidence is sufficient to engage the section.  In my view there is sufficient evidence of mining subsidence in this case for the onus to pass to the respondent.  The reason for this conclusion is that Mr Ottaway, when asked about the WYG report on No.46 in 2005, said that High Main Seam E was a consideration relevant to the ground investigations that he helped to design at that time.

77.        Nevertheless, the onus on the respondent is no more than to prove its case on the balance of probabilities (see Burton and Burton v National Coal Board dated 22 April 1982, V G Wellings QC, REF/122/1979, unreported, in respect of an identical provision in the Coal-Mining (Subsidence) Act, 1957, s13(2)).  Since, in my judgment, Mr Ottaway’s evidence is to be preferred to that of the claimant’s experts, that onus has been discharged.  I therefore determine that the damage caused to 48 Stocksfield Avenue was not subsidence damage caused by the withdrawal of support from land in connection with lawful coal-mining operations.  A letter on costs accompanies this decision, which will take effect when the question of costs is decided.

Dated 5 July 2010

 

N J Rose FRICS