Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
Table of Contents Introduction ...... 3 Historical Subsidence Features ...... 4 The Pond ...... 4 Borehole Site Investigations ...... 7 Site Geology ...... 8 Field Pattern, Topography & Ground Stability ...... 9 Drift Condition & Ground Stability ...... 9 Bedrock Condition and Ground Stability ...... 10 Comparative Instability Risk – Zone C Ripon ...... 12 Foundation Design ...... 13 Other Mitigation ...... 13 Ground Stability Declaration ...... 13
TM Units 3a and 4 Terry Dicken Industrial Estate Ellerbeck Way Stokesley North Yorkshire TS9 7AE Tel. 01642 713779 Fax 01642713923 Email [email protected]
www.geoinvestigate.co.uk 2 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
Introduction Phase Site Investigations provided Kebbell Homes with a geophysical survey report (Project ref GEO/2722/1023) for the site in November 2019.
The Phase report is available from Kebbell Homes. It is not included in this report as it is assumed it will form part of the planning application for the Church Farm site by Kebbell Homes.
The Phase report identifies two possible broadly li ea i og a it a o alies A a d B at the site. Anomaly A located in the north is larger and stronger, while B along the southeast site boundary is weaker and perhaps smaller.
The geophysical report is uncertain whether the anomalies are gypsum related dissolution features speculating that they might instead arise from variations in geology, soil compaction or possibly even anthropogenic activity i.e., human activity concluding that the only way the uncertainty could be resolved was by intrusive investigation.
Encouragingly the Phase SI report mentions that EM geophysical survey indicated that that there are no infilled troughs or peat deposits at the Church Farm site which are known to be associated with much older sinkhole activity in the Ripon area.
The anomalies are indicated as BLUE areas in the subsequent desk study ground stability report carried out by Geoinvestigate, emailed to Mr Mike Mulligan of Kebbell Homes on 29 January 2020 and provided in Appendix A
As part of the desk study the tentative rough historical subsidence hollow map provided in Appendix B was generated for the site and the surrounding area based on the OS map record dating from 1854. This base map was not included in the email of 29 January 2020 to Kebbell Homes. The map of 1891 is the first map showing a small circular water feature/spring or perhaps even a small embryonic sinkhole to the southeast of the site. Sometime after 1957 and by 1975 the feature is shown as a larger recognisable pond.
The origin of the pond feature is discussed in Geoinvestigate s early 2020 ground stability report and subsequently with Dr Tony Cooper in several informal email exchanges. Dr Cooper of the Natural Environment Research Council and the British Geological Survey, Emeritus is the UKs recognised leading authority on the e gi ee i g geolog of ‘ipo s gypsum dissolution problem.
Subsequently, Dr Cooper was engaged late 2020 as a specialist consultant by Geoinvestigate to provide advice on the engineering geology of the gypsum beneath the Church Farm site and specifically to provide a report on two 45m and 50m deep rotary cored boreholes sunk at geophysical anomalies A & B in September 2020.
Initially Geoinvestigate suggested that owing to the COVID pandemic and Dr Cooper shielding during this period that the core boxes were delivered to his home address to be logged by him. However, rather than receive core boxes it was felt safer for Dr Cooper to evaluate photographs of the core both in its original condition and split open (to remove surface smearing) and these were sent to him in April 2021. Subsequently Dr Cooper called for the core samples themselves to be delivered to his home for further preparation and detailed logging by him which was done in March 2021.
www.geoinvestigate.co.uk 3 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
Dr Coopers detailed report on the borehole cores issued March is presented in Appendix C together his high- resolution core photographs. Dr Cooper is an accomplished amateur photographer.
Follo i g D Coope s loggi g, the cores were picked-up and returned to Geoinvestigate s Stokesley Head Office in April 2021 for longer term storage.
Subsequently Geoinvestigate compiled logs of the cores incorporating Dr Coopers logging information. Geoi estigate s logs ‘C a d ‘C at geoph si al a o alies B a d A espe ti el a e p ese ted i Appendix D
Historical Subsidence Features The draft base map provided in Appendix B shows subsidence hollows, ponds, sinkhole collapse events, speculative ground water movement direction and other features of interest with respect to understanding the ground stability and gypsum dissolution situation local to the Village of Bishop Monkton and the Church Farm site.
Following discussions with Dr Cooper two features, a pond which appeared sometime between 1851 – 1910, and a ground collapse c. 1830 occurring well to the west and east of the site respectively were added to the map.
The appearances of the features or the first recording of them date mostly to the mid to late 1800s and early 1900s.
Four ground water pumps (shown yellow circles) believed to be perhaps two wind and two hand pumps located in farmland and at a farmstead to the east of the site are shown on the map. It was speculated in Geoinvestigate s desk study report that the formation of some of the subsidence hollows and ponds might be connected to ground water pumping in the late 1800s and early 1900s.
As far as Geoinvestigate has been able to ascertain, few significant recent (within the last 80 years and probably longer) subsidence events/features have been reported/documented within and around the Village of Bishop Monkton and its immediate surrounding area.
The Pond The o spi uous la ge pe petual pond to the southeast of the site lies at a rim height of 34m AOD while the development area is at 37m to 38m rising locally to 39m AOD. Ground level rises gradually from the pond to the site. The pond occupies a wider depression/bowl crossed to the northwest by an ancient/old hawthorn hedge and the caravan park access track which may be slightly embanked. According to the site owner the pond outflows to the southwest onto lower lying ground where a second pond is formed intermittently. Recent 2020 images of the pond are shown in Appendix E
On 26 April 2021 Ross Nicolson spoke to Emma Oates the landowner and the caravan site manager. According to her recollections the land was acquired some 23 years ago (1998) by her family/partners family. She grazes her horses in the pond field but had no recollection of the pond enlarging during this period or any excavation or infilling of it or raising of its banks. Her family had moved to Bishop Monkton in the 1950s and she was not aware of any ground instability event within the site or the pond or the village during this period.
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With respect to the pond depth, she did t k o ut guessed it might be 2m or so placing its bottom at perhaps 32m AOD. Her horses did t ade i to the middle of it.
Selected historical maps used to illustrate this section of the report are presented in Appendix F together with a recent Google satellite image of the pond. A full set of larger and smaller scale historical maps dating from 1852 are provided as part of the Phase 1 Desk Study reference materials in Appendix 1.
The pond is first recorded as a small circular feature (perhaps a spring) on the OS map of 1891 and remains a small map feature up to 1957. By 1974/1975 it is shown as a larger feature of some 24m width x 29m length and 0.049ha area remaining the same size on the later map of 1989 – 1994 when it is shown some 62m from the southern site boundary.
By 2003 the pond is much larger 35m x 55m, 0.197ha, and 4 times its previous surface area and now some 42m to 45m from the site boundary. The most recent Google satellite image suggests that the pond has not increased noticeably in surface area since 2003 though the northeast margin adjacent to Knaresborough Road and the east field line have perhaps been infilled in recent years. An image of possible infill material on it s roadside rim is shown in the Appendix G.
Much of the change in size of the pond and the subsidence arising from dissolution of the underlying gypsiferous bedrock may date from around 1960s perhaps slowing in recent years post 2003.
The pond appears to be fed by a drainage ditch lying to the east of the site and the road. However, no obvious connection or culvert was observed linking the ditch and the pond and the site owner was unaware of its presence. While the ditch was observed to be dry in September 2020 the pond was full.
It is speculated that enlargement of the pond over the years may have caused the demise of a large tree in the old hawthorn hedgerow to the north of the pond. Hawthorn is more tolerant of wet ground.
The pond and the land to the southwest and west of it adjacent to the site the site all lie in an area of lower lying ground comprising several connecting depressions. Lidar drainage interpretation of the locality in Appendix H confirms that these areas form a preferential drainage low point surrounding the site which is higher.
It is speculated that the lower lying ground and the natural surface water drainage network skirting the site to the south and west was perhaps wet meadow/pasture liable to flooding and unsuitable for crop growing only grazing. It is speculated that the purpose of the ancient hawthorn hedge which broadly follows the margin of the low ground and has a conspicuous dog-leg alignment shadowing it separated livestock from the ridge and furrow crop fields lying to the north of the pond within the higher field where the proposed housing development is located.
Lidar imaging shows an ancient linear ridge and furrow field pattern within the development area with the pattern appearing to curve round the northern rim of the pond but not extending to the south of the hawthorn hedge. Sections of relict ridge and furrow pattern can be seen on the south side of the pond and far west margin of the lower lying area but not within drainage network itself suggesting that the pond depression and the lower lying ground in the vicinity of the site have been present for a very long time.
A Google Street View image of 2008 in Appendix G suggests that the semi-circular indentation shown on the northern rim of the pond in 2003 may have been infilled with the material heaped at the pond edge in this image. It is speculated that the indentation may indicate instability of the pond edge. www.geoinvestigate.co.uk 5 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
I Geoi estigate s opi io eighi g all the evidence, suggests that the increase in the size of the pond over the years and mostly from the early 1960s probably points to the slow ongoing progressive dissolution of the underlying gypsum geology beneath the pond locality. Dr Coopers report is of similar opinion.
I Geoi estigate s opi io this has ee o u i g fo a e lo g ti e as e ide ed the e old/a ie t hedgerow and the agricultural pattern which were adapted to it.
Ground water level was recorded at 31m AOD in September 2020 in borehole CP/RC1 adjacent to the pond and it is possible that the perpetual nature of the pond may in part be due to upwelling of groundwater at this low point which may approach 32m AOD or less at the pond base. This however is speculation.
The winter water level in borehole RC1 could be expected to be higher and originally the smaller feature seen on the maps of 1891 may have been a spring. The higher ground at 39m AOD within the site may help drive the ground water to surface at the pond.
Interestingly, St Johns (Council) Estate some 60m to 70m to the northeast of the site built in the 1960s and on similar geological strike to the proposed Church Farm development with perhaps similar gypsum geology below it has a large pond near it to the north within the Ings Farm property.
The Ings Farm pond lies at 29.88m AOD and first appeared sometime between 1957 and 1974 within the same time frame that the Church Farm pond proper appeared. The Ings Farm pond is located some 250m due north of the Church Farm pond. The nearest estate housing to the Ings Farm Pond lies 20m and 40m to the south and west of it and the main access road into the estate is 15m or less from its rim.
In our opinion it is possible that the Ings Farm pond is evidence of gypsum dissolution and subsidence at this locality. This however is speculation.
As far as we have been able to ascertain there is no documented occurrence of a sinkhole collapse at the Church Farm or Ings Farm ponds and according to Emma Oates there has been no sudden subsidence event at the former either since their tenure of the farm began in 1998.
None of the older buildings in Bishop Monkton Village or the St Johns Council Estate would have special foundations to mitigate gypsum dissolution hazard. This is a relatively recent requirement.
A site reconnaissance survey at Bishop Monkton village by Ross Nicolson in 2020 found no obvious visible surface evidence indicative of ground subsidence within St Johns Estate, St John the Baptists Church (only 50m north of the Church Farm site) or the housing on St Johns Road or within Bishop Monkton Village save for perhaps the buttressed end of the old corner house at the corner of St Johns Road and Knaresborough Road opposite the church. An image of the later is provided in Appendix I. However, it is our opinion that this localised buttress support may be due to a leaning gable wall, structural building inadequacy and or and the presence of weak ground associated with the adjacent Bishop Monkton Beck.
The overall impression gained from the desk study and the walkover reconnaissance inspection of the Bishop Monkton area is that while historically subsidence and sinkhole collapse events/features are present in the area they are relatively few, with little or no documented collapse occurring in say the last 80 years.
www.geoinvestigate.co.uk 6 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
An account of a significant historical ground collapse in 1830 in the Bishop Monkton area provided by Dr Cooper is presented in Appendix J and is a sobering reminder of what can happen in the extreme. Dr Cooper is however uncertain of the exact location of this event, but it is likely to be distant from the Church Farm site.
So, collapse events can very occasionally occur in the Bishop Monkton area, but they are relatively rare and in our opinion are much rarer here in comparison with other parts of Ripon.
In our opinion the Ings Farm Pond and Church Farm Pond may be indicative of more recent and perhaps slow ongoing dissolution at both locations.
I ou opi io Bishop Mo kto is a elati el uiet a ea ithi ‘ipo ith respect to gypsum dissolution activity and subsidence events and for this reason has not been the focus of sinkhole hazard assessment and zonation which has focussed mainly on the Town itself. Broadly, this is also the view of Dr Cooper though everywhere in Zone C even at Bishop Monkton there is always potential sinkhole hazard. Because of this risk intensive site investigation is required together with robust precautionary foundation mitigation however favourable the outcome of site investigation might be.
I Geoi estigate s opi io g psu dissolution currently remains largely unpredictable both in its place, nature/type (whether sudden collapse or gradual subsidence) and timing in the Ripon area. Recently the BGS stated that dissolution can occur in a lifetime though it is still unclear what is meant by this.
Because of the unpredictability of gypsum dissolution and as most building development is located in Zone C within a higher risk area, Geoinvestigate believes that the most important outcome of SI is to ensure that new development avoids locating buildings over existing or imminently unstable ground arising from pre-existing or developing large voids or cavernous ground both posing the greatest immediate threat to life and property from sudden large scale sinkhole collapse.
In our opinion, identifying current ground instability hazard is a more safely achievable with larger numbers of probe holes (without core sample recovery) than best guessing the future behaviour of the complex gypsum geology beneath a large housing estate with say only one or two very expensive boreholes with core sample recovery. In our opinion, the best arrangement is for the investigation of gypsum hazard is multiple probe holes with reference boreholes with continuous core sampling.
So, for a new multiple housing development in Ripon, Geoinvestigate prefers at least one deep probe hole to be made per house and this should confirm that there was no imminent collapse threat.
Borehole Site Investigations Church Farm is possibly one of the most intensively investigated sites in the Ripon area perhaps only second in drilling intensity to Ripon Auction Mart in the Town.
At Church Farm the drilling investigation of the surface drift horizon which extends to 15m depth or so comprised 20 window sampling boreholes (BH1 – BH18) to depths up to 4m across the site together with 2 deep cable percussion boreholes each to around 15m in drift at CP1 and CP2. Broadly one window sampling hole was drilled per proposed house location.
20 microdrill probe holes without core recovery were carried out across the site (one per house) to depths between 38m to 50m to investigate the underlying bedrock geology primarily for the presence of cavities and voids which may be indicative of existing sinkhole hazard.
www.geoinvestigate.co.uk 7 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
12 additional deep microdrill holes in two clusters of 7 (RHB1 – 7) & 5 holes (RHA1 – 5) were sunk around boreholes RC1 and RC2 at anomalies A & B to check for cavities.
Geoi estigate s p op ieta i od ill s ste reates very small holes of 45mm diameter these being some 11 times smaller than the larger 6 inch/150mm OD boreholes used to recover core at Church Farm.
While micro-holes by their nature cannot be grouted over their full length in our opinion, they pose much less threat of creating major pathways into the gypsum horizon than larger boreholes. This is because small holes will self-seal or plug much more readily than larger holes.
Small volume water flush Microdrilling is also much safer than percussive air hammer drilling which would subject a sensitive bedrock condition like gypsum to extreme repetitive high frequency impact shock energy/vibration at the same time releasing large volumes of compressed air with the attendant risk of de- stabilising an already unstable situation and possibly causing ground collapse during drilling.
The microdrill hole logs at Church Farm also record approximate drift/bedrock depth, the depths and thickness of the underlying Brotherton Limestone Formation, the thickness of the Edlington gypsiferous marl horizon beneath it and the upper part of the Cadeby Limestone basement strata. However, as no core is recovered the strata depths and thicknesses shown on the logs are very approximate and perhaps liable to differences of perhaps 2m or 3m metres when compared to nearby borehole cores.
Both larger diameter deep boreholes RC1 and RC2 were sealed over their full depth with bentonite pellet infill. Geoi estigate s Phil Gaffney assisted the drilling sub-contractor with infilling of the boreholes and made a photographic record of it.
Site Geology The site geology is best characterised by both cable percussion by the logs of follow-on rotary core boreholes CP/RC1 and CP/RC2 located at the far south and north ends of the site corresponding with geophysical anomalies B and A respectively
The site geology in both boreholes is described and discussed in detail in Dr Coopers report in Appendix C.
The Executive Summary from Dr Coopers report is presented below.
Executive summary. This report reports on the geological logging of boreholes 1 and 2 drilled for Geoinvestigate at Bishop Monkton south of Ripon. The national grid references derived from the supplied Google image and GIS interrogation are for Borehole 1- 432872,465828 and for Borehole 2- , 0 . These NGR’s eed co fir i g by Geoinvestigate. The two boreholes show similar sequences with superficial deposits to a depth of around 15.00 m. Beneath this both prove the Brotherton Formation dolostone/ dolomitic limestone, but it is indicated to be broken and recovery was poor. In addition, borehole 2 included material collapsed or washed in from above suggesting a complex collapse, possibly into a sinkhole; this made the Brotherton Formation appear locally thicker. Beneath the Brotherton Formation the strata of the Edlington Formation was largely brecciated or dissolution residues in borehole 1 and partially brecciated in borehole 2. In borehole 1 all the gypsum had nearly all dissolved and in borehole 2 about 1.80 m of gypsum remains in the sequence. Depending on the groundwater flow this has the potential to dissolve and there is some evidence of dissolution in ground adjacent to the site where a pond has enlarged in size over the past 100 years or so. Both boreholes penetrated the limestones of the Cadeby Formation, the geological unit that in general supplies water under artesian pressure to the overlying strata forming the mechanism for gypsum dissolution.
www.geoinvestigate.co.uk 8 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
Field Pattern, Topography & Ground Stability The relict ancient ridge and furrow system with the main field at Church Farm is strongly linear and undisturbed suggesting that there is no localised sinkhole activity in the field and its southern margin and beyond it and the track in the next field up to the old hawthorn hedge and both larger and small fields have remained stable in this regard for a very long time.
The pattern in the smaller field between the access track and the pond is slightly curved suggesting that it was fitted to a pre-existing depression at this location. The line of the hawthorn hedge also suggests it followed the northern margin of a depression and area of low-lying ground perhaps wet meadow and pasture to the south and west of the site.
Both the field pattern and the old hedge line and the absence of ridges in the pasture/meadow to the south and west of the site indicate that a depression possibly caused by gypsum dissolution has existed at this locality for a very long time. Changes in the size of the pond suggest that dissolution is continuing at the pond causing its initial appearance post 1957 and further expansion between 1997 and 2003.
Subsequently the pond is little changed perhaps indicating that dissolution activity beneath it has slowed in recent years.
Drift Condition & Ground Stability The upper drift/soil horizon within the site extends to around 15m depth comprising mostly firm and stiff gravelly clay, firm to stiff laminated clay and dense to very dense sand and gravel in both shallower window sampling holes and deeper cable percussion boreholes.
Stiff, to very stiff reddish brown gravelly clay perhaps of Glacial Till/Boulder Clay horizon is present at the base of the drift above the Brotherton Limestone Formation perhaps suggesting that the Brotherton was stable during the last glacial deposition cycle.
Dr Cooper s report and our observations of the core suggest that the limestone has extensively foundered/subsided/collapsed in both deep rotary boreholes due to extensive past dissolution of the underlying unstable gypsiferous marl/mudstone horizon causing the limestone above it to exhibit a very weak and broken/rubbly condition giving rise initially to very poor core recovery and the loss of drill flush in this bedrock strata.
None of the 22 drift sampling holes encountered anthropogenic infill, peat or weak ground conditions indicative of disturbance caused by sinkhole collapse. Indeed, the undisturbed nature of the drift and the very stiff clay layer immediately above bedrock may suggest that perhaps much of the foundering of the underlying limestone occurred before the drift was deposited this movement may be ancient perhaps dating thousands of years to the last glacial period. This is also D Coope s opi io .
In our opinion, there is little significant difference between the drift boreholes, across the site and within, or near anomalies A & B that would readily account for the apparent geophysical differences at these locations.
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Bedrock Condition and Ground Stability No cavities were encountered in the 20 deep rotary boreholes sunk across the site essentially at random positions as well as in the 14 additional deep holes including 2 cored holes clustered at geophysical anomalies B & A.
So, in total 34 deep holes found no cavities which is very encouraging with respect to current dissolution and sinkhole activity beneath the site.
In our opinion this favourable drilling outcome considerably reduces the risk of the occurrence of unstable ground within the site and locating new building development over existing large voids and/or cavernous ground.
In our opinion the deep drilling investigation has provided no obvious explanation either for the anomalies at A & B and there appears to be little significant difference between the localities themselves.
The 2 deep borehole cores recovered from the site indicate that the gypsiferous horizon lying at 30m and 35m depth beneath the proposed Church Farm housing development has been much depleted of unstable gypsum deposits in both boreholes by past dissolution activity. Gypsum is almost completely absent in borehole RC1 and reduced to a combined thickness of only 1.80m, according to Dr Cooper, in RC2 between 39m to 43m depth with minor gypsum veins and traces above and below this in the same core.
The difference in residual gypsum thickness at the borehole locations approaching (0) in RC1 and 1.8m and perhaps a little more in (RC2) may perhaps explain the difference in the thickness of the Edlington Formation of 11m in RC1 and 14m in RC2.
Consequently, based on the borehole results while there is in our opinion little potential for further dissolution at RC1 there perhaps remains some limited potential for future activity at RC2.
Because the main gypsum horizon/seam at 39m depth in RC2 appears intact, competent and not voided or vuggy or containing large pores this suggests that this zone is currently not wasting away by groundwater movement the inference being that currently dissolution activity is low level at this borehole locality.
The original core photographs taken by Geoinvestigate and presented in Appendix K and those in Dr Coopers report show the recovered cores samples in the gypsiferous Edlington Formation are generally quite compact even where this is clear evidence of previous collapse and coarse infilling/breccia eg at 39m to 40m depth in RC1 suggesting the gypsum horizon has consolidated/compacted over a considerable period of time (perhaps many thousands of years) beneath the Church Farm site.
The Brotherton dolostone capping has naturally adjusted to the removal of massive quantities/thickness of gypsum in the underlying Edlington Formation (30m to 40m thickness lost a o di g to D Coope s epo t) and the significant volume changes and collapse that would have accompanied this. This resulted in the foundering of the overlying limestone and its highly fractured/broken and rubbly condition giving rise to very difficult drilling conditions, poor core recovery and high drill water losses in this horizon. On the other hand, the Cadeby Limestone located below the unstable gypsiferous horizon is highly competent and strong. The marked contrast between the two limestone horizons is clear from the borehole photographs.
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Dr Cooper, in an email to us, suggested that the difference in the levels of the Cadeby horizon 41m depth in RC1 and 49m in RC2 is out of step given the boreholes lie on more or less the same geological strike with W to E dip could be explained by the subaqueous dune environment in which the strata might have been deposited with highs and lows.
The deep micro-drilling results across the site broadly confirm that the Cadeby rises appreciably towards the south end of the site and borehole RC1 and falls towards the north end and RC2 and this difference is depositional and not caused by geological faulting between the two borehole positions.
While gypsum dissolution has caused significant volume change and ground movement and collapse in the Edlington Formation as well as movement and collapse in the overlying Brotherton Limestone, the intensive drilling investigation at the site has found no evidence that similar ground disturbance indicative of sinkhole activity or subsidence extends through the overlying drift deposits. These remain by comparison undisturbed.
Neither does the relict ancient ridge and furrow farming pattern, which is largely intact at Church Farm, indicate that instability is present anywhere within the site either between borehole positions or over or near geophysical anomalies A & B. Neither is the ground between the access track and the pond rim disturbed by recent sinkhole activity.
Consequently, it is our opinion that much of the underlying instability that is recorded in the borehole cores in the Brotherton and Edlington horizon is of considerable geological age pre-dating the deposition of the surface drift/soil layer which has remained essentially undisturbed stable within the Church Farm site for many thousands of years.
Despite this favourable situation and because drilling has shown that gypsum remains beneath the site and its location and behaviour is unpredictable in Zone C where there is always the risk of future ground instability to a greater or lesser degree it is our opinion that there remains some potential for future ground instability at Church Farm, though the risk, in our opinion, is very much lower here than in many other parts of Ripon.
For this reason, in our opinion as a precaution mitigation is required in the design of the housing scheme to safeguard it against future ground instability hazard albeit after intensive site investigation this is considered by Geoinvestigate to be low risk at this locality.
Intensive drilling investigation of Church Farm indicates that large voids and cavernous ground that could give rise to sudden sinkhole collapse hazard are unlikely to exist below the new development and under each new house within it. In our opinion such hazard poses the greatest immediate tangible risk to the safety of any development within Zone C Ripon and drilling has shown it is not present within the site.
While there is perhaps recent, slow localised dissolution activity and subsidence offsite to the southeast of the development at the pond, as it is 50m distant from the proposed nearest housing unit, it is not, in our opinion, considered to pose significant future ground stability risk to the development and the new site access road.
In addition, as there is evidence that activity has slowed or halted at the pond in recent years the risk may be further reduced - though this report does not rely on this in the conclusion it reaches with respect to the appropriate mitigation.
www.geoinvestigate.co.uk 11 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
Potentially similar conditions may exist at the nearby St Johns Estate where housing development has co- existed in closer proximity (20m) to a similar large pond without any apparent problems, in addition the road to the Estate is even closer.
An insight to what the original pond feature to the east of the Church Farm site might have looked like 100 years ago when it was much smaller is provided in Appendix L. The image shows Dr Cooper leading an Engineering Geology field excursion visit to a recent (perhaps 2018) sinkhole appearance in Ripon Town. The diameter of the water filled hole is about 1.5m. Subsequently it was filled with stone by the Council only reappearing again sometime later with water trickling from its collar in winter.
Two blocks of nearby flats to the rear of the group next to the road were demolished at the same location in 2009 because of ground instability. Other housing and a relatively new NHS rehabilitation centre all positioned some 25m from the feature, are unaffected.
Comparative Instability Risk – Zone C Ripon In our opinion it is useful to compare Church Farm with other recent developments in Zone C Ripon to get a qualitive measure of the ground instability risk to this new building proposal.
In this regard, two widely reported projects come to mind. Firstly the redevelopment of Ripon Auction Mart and secondly the new swimming pool at Ripon Leisure Centre on Dallamires Lane both located in the Town.
At the Auction Mart (perhaps the most intensively investigated land in Ripon) the site investigation provided evidence of extensive past ground instability including perhaps recent sinkhole activity, peat, weak ground, collapsed ground and infilled ground. This and the recent nationally reported sudden large sinkhole collapses at adjacent Magdelans Close and Magdelans Road in 2014 & 2016 together with the presence nearby of historical sinkhole features/subsidence hollows at Paddies Park, The Beeches Farm and building subsidence damage at the farm and St Marys Almshouses next to it suggest the Auction Mart is a higher risk area within Zone C.
After consideration of the site investigation report Ripon Council concluded that the future gypsum dissolution hazard at the Auction Mart was not predictable and withheld planning approval for bricks and mortar housing development subsequently passing a smaller mobile homes development.
At the new swimming pool, recent recurring sinkhole activity is believed to have arisen during or shortly after site investigation at a locality where there is previous site investigation evidence indicative of pre-existing of doline karst geology with irregular bedrock profile, infilled ground, peat and soft ground all suggesting a higher risk instability environment causing several councillors to abstain or vote against this planning application in 2019.
In comparison, the Church Farm site is in our opinion LOW risk.
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Foundation Design Fou datio desig i the ‘ipo s Zo e C he e si khole isk is identified often entails robust raft slab construction spanning a potential ground collapse feature of 3m diameter or in more recent years 5m diameter and capable of cantilevering over it by half that diameter.
In 2019 according to an article in the Harrogate Advertiser 4th April 2019, Harrogate Council took the unprecedented decision to adopt a supe aft fou datio ith e te sio ea s ai ed at withsta di g a sinkhole up to 20 meters in diameter togethe ith escape pathways’ to safeguard the occupants of their flagship Allhallowgate and Finkle Streets housing block redevelopment ea the To s e t e.
Subsequently the Council scrapped the scheme after enthusiastically promoting it.
While in our opinion the sinkhole risk at the Church Farm site in Bishop Monkton is LOW it cannot be discounted altogether. Therefore, rafts are recommended spanning 3m through much of the site with very robust rafts capable of spanning 5m approaching the southern site boundary and the pond where at the latter gypsum dissolution activity may be occurring some 50m off-site from the nearest proposed housing development.
Other Mitigation As a precaution all types of soakaways and SUDs drainage systems discharging water into the ground must be avoided within the site. Closed loop GSHP should also be avoided. Additionally, water supply, water systems and drain-pipes should be doubly checked during their installation to ensure that they are not leaking.
Ground Stability Declaration Based on the favourable findings of the site investigation, Geoinvestigate Limited has no hesitation in providing a favourable Ground Stability Declaration for the Church Farm housing development proposal.
www.geoinvestigate.co.uk 13 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
Appendices
A 29 January 2020 report to Kebbell Homes
B Historical subsidence hollow map
C Dr Coopers Report
D Geoi estigate s o ehole logs CP/‘C & CP/‘C
E Pond images
F Historical maps
G Pond infill
H Lidar imaging
I Buttressed building
J Reverend Tute s 8 si khole a ou t at Bishop Mo kto
K Geoinvestigates core photographs uncut and cut
L Recent sinkhole activity in Ripon Town
END OF REPORT
www.geoinvestigate.co.uk 14 April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
The findings and contents of this (intrusive) Site Investigation Report pertain solely to the study area(s) outlined herein and are based solely on the findings of the excavations undertaken as part of the current exercise unless otherwise stated. The findings and/or recommendations of this report do not take into account any ground conditions that may be present but have hitherto not been encountered and as such further investigation and/or a reconsideration of the findings of this report should be undertaken if such conditions are subsequently encountered or an alternative development plan or land use is subsequently proposed.
This report considers various environmental and/or geological risks posed to the site and/or proposed development and offers advice accordingly as guidance only. The findings of this report will remain valid provided no change of ground or groundwater conditions, either natural or anthropogenic, take place and no warrantee is offered or implied.
No copying of this report or any part of its contents is permitted without written permission of Geoinvestigate Ltd. nor should the report be made available to any third party without similar prior arrangement.
TM
Units 3a and 4 Terry Dicken Industrial Estate Ellerbeck Way Stokesley North Yorkshire TS9 7AE
Tel. 01642 713779 Fax 01642713923 Email [email protected]
www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
APPENDIX A 29 JANUARY 2020 REPORT TO KEBBELL HOMES
www.geoinvestigate.co.uk April 2021 Church Farm Bishop Monkton
Geophysical Survey Project No. GEO/2722/1023
November 2019
© Phase Site Investigations Ltd, 703A Whinfield Drive, Aycliffe, Business Park, Newton Aycliffe, DL5 6AU
Church Farm, Bishop Monkton Geophysical survey
Table of Contents 1. INTRODUCTION 1 1.1 OVERVIEW 1 1.2 GEOLOGY 1 1.3 SCOPE OF WORK AND SITE DESCRIPTION 1 2. SURVEY METHODOLOGY 2 2.1 MICROGRAVITY SURVEY 2 2.2 FIXED FREQUENCY ELECTROMAGNETIC (EM) SURVEY 2 2.3 DATA PROCESSING AND PRESENTATION 3 3. RESULTS & DISCUSSION 4 3.1 MICROGRAVITY DATA 4 3.2 FIXED FREQUENCY EM DATA 4 4. CONCLUSIONS 6
DRAWINGS GEO_2722_1023_01 Site location map GEO_2722_1023_02 Geophysical survey extents GEO_2722_1023_03 Microgravity data: residual Bouguer Anomaly GEO_2722_1023_04 Electromagnetic conductivity data GEO_2722_1023_05 Electromagnetic in-phase data GEO_2722_1023_06 Interpretation of geophysical data
REFERENCES 7
APPENDIX 1 Electromagnetic conductivity survey; technical information 8
APPENDIX 2 Microgravity survey; technical information 13
Project No. GEO/2722/1023 12/11/2019 Church Farm, Bishop Monkton Geophysical survey
1. INTRODUCTION 1.1 Overview Phase Site Investigations Ltd was commissioned by BWB Consulting Ltd to carry out a combined electromagnetic (EM) and microgravity survey at a proposed development site in Bishop Monkton, North Yorkshire. The site is in an area of suspected gypsum dissolution features and the objective of the survey was to identify if solution features / voids are present at depth within the site and to identify if there were any areas of historic subsidence present near the surface that may be filled with a different material, such as peat. The location of the site is shown in drawing GEO_2722_1023_01. 1.2 Geology The geology of the site consists of limestone of the Brotherton Formation with superficial deposits of clay, sand and gravel of the Vale of York Formation (British Geological Survey, 2019). A geotechnical assessment for a different site on the northern side of Bishop Monkton (confidential report) indicated that the anticipated geology for that site was likely to superficial deposits (likely firm / stiff clays) underlain by limestone of the Brotherton Formation, which in turn is underlain by the Edlington Formation. Gypsum deposits are anticipated within the Edlington Formation. The superficial deposits were estimated to be in the order of 10 m depth, the Brotherton Formation could be up to 15 m thick and the Edlington Formation could extend to depth in the order of 30 m to 60 m. It is likely that similar geological conditions exist at this site but it is recommended that a site specific geotechnical assessment be undertaken to confirm this. 1.3 Scope of work and site description The site is located off Knaresborough Road, on the southern edge of Bishop Monkton, North Yorkshire, approximately 5 km to the south-east of Ripon (centred at NGR SE 329 659). The site is approximately 1.2 ha in area. The majority of the site was a grass field with dense vegetation (trees, bushes and undergrowth) in the north, east and south-east. A line of trees and undergrowth was present in the south of the field. The site was bounded to the south, south-east and west by an access track, which curved in the west. The ground was undulating in parts with the northern third (or so) of the field slightly lower than the rest of the field with a low bank present between these areas. The survey was extended slightly to the west, where the site boundary curved, to obtain a regular shape to the survey area. The site boundary and the geophysical survey extents are shown in drawing GEO_2722_1023_02. A microgravity survey was undertaken to try and locate potential deeper voids and areas of loose material. A fixed frequency electromagnetic (EM) survey was undertaken to try and identify any near- surface variations that may indicate the presence of historic areas of subsidence. The survey was carried out on days between 17 October and 29 October 2019. During this time there was a prolonged period of wet weather, which resulted in the ground becoming waterlogged and soft.
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2. SURVEY METHODOLOGY 2.1 Microgravity survey The microgravity survey was carried out using a Scintrex CG-6 microgravity meter. The CG- 6 is an automated gravity meter with a resolution of 1µgal. The gravity data was undertaken as a series of readings taken at 4 m intervals. The survey grid was established and tied-in using VRS RTK GNSS. The position and level of individual survey station points was recorded using the GNSS. The survey was undertaken as close to the boundaries as was possible given the site conditions. A base station was established on a small area of concrete situated in the south-east of the site. The base station was revisited at intervals not exceeding one and a half hours throughout the duration of the survey. Measurements were taken for a period of 60 seconds at each station from which an average value was calculated by the instrument. 10% of the readings were repeated and over the majority of the site the maximum repeat error was between 0 μGal and 3 μGal, however, there were some occasions where the repeatability was down to 5 μGal or 6 μGal, where the ground was softer. The repeatability values indicate that the data for the site was very good (repeat readings within 3 μGal to 5 μGal of the original value indicate high quality data). The Earth tide corrections were calculated internally by the CG-6 instrument. A more detailed technical summary on the theory and survey methodology of the microgravity technique can be found in Appendix 1. 2.2 Fixed frequency electromagnetic (EM) survey There are two principal components to the fixed frequency EM data, known as the quadrature and in-phase components. The quadrature component is a measure of apparent electrical conductivity of the sub-surface and so the data relating to this is referred to as conductivity. This can relate to either the amount of moisture within the sub-surface or the presence of metallic or conductive features. The in-phase component measures the phase difference of the induced field that is detected by the receiver coil. A strong phase shift generally indicates the presence of metallic features. For these survey objectives the conductivity data is the most valuable but for the sake of completeness both datasets were recorded. The survey grids were established and tied-in using VRS RTK GNSS. The survey was undertaken as close to the boundaries as was possible given the site conditions and limitations of the equipment. A GNSS was linked directly to the datalogger and each data point was referenced to UTM co- ordinates. These were converted direct to Ordnance Survey co-ordinates using the UK OSTN 02 projection. Each profile was spaced 1 m apart and a reading was taken at the equivalent of at least 0.5 m increments. Simultaneous readings of conductivity and in-phase were measured with the instrument in vertical mode. The instrument was balanced and ‘zeroed’ at a base station that was established on a sufficiently ‘quiet’ area (one which has a uniform background of EM values), within the site. A Geonics EM31 was used for the fixed frequency EM survey. The EM31 consists of a large 3.7m long boom which extends to either side of the operator and restricts how close the operator can be to obstructions located on either side. Readings are taken by pressing a
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button which does mean that the operator can manoeuvre around some obstructions in between taking readings. A more detailed survey methodology and technical summary of fixed frequency EM can be found in Appendix 2. 2.3 Data processing and presentation The microgravity data was downloaded from the instrument using bespoke software specific to the CG-6. The raw data has been corrected and reduced to the Bouguer Anomaly using in- house software and gridded using the Kriging method in Surfer (Golden Software). A second order polynomial surface (approximated regional field) has been fitted to the data and subsequently removed to produce the residual Bouguer Anomaly. The variations in height across the survey area were significant enough that terrain corrections were required for the microgravity data. The terrain corrections were calculated using the microgravity module of Oasis Montaj v. 9.7 (Geosoft Software). A local terrain grid of the 3D points from the topographic survey of the site was merged with a regional terrain grid compiled from opensource Lidar data (Enviornment.data.gov.uk, 2019). This combined terrain grid was then used by the software to calculate corrections to each data point to compensate for the changes in topography across and adjacent to the site. The terrain corrections were applied based on a local correction distance of 50 m from the individual stations. The effects due to terrain features at distances greater than 50 m, while possibly large in magnitude, will influence each survey station value by an equal amount and so the relative gravity effects from these features can be ignored (summarised from Sharma, 1997). The microgravity data was analysed over a range of values and a plot of the residual Bouguer dataset was then exported from the gridding software in .png format. This was then imported into AutoCAD direct to OSNG and is presented in drawing GEO_2722_1023_03. The EM data was downloaded from the instrument using bespoke software specific to the EM31. The data was imported into the gridding software Surfer (Golden Software) and gridded using a ‘kriging’. No further processing was carried out. The EM data was analysed over a range of values using plots of the conductivity and in-phase datasets. The data plots were exported from the gridding software in .png format and then imported into AutoCAD direct to Ordnance Survey National Grid (OSNG). Plots of the conductivity and in-phase data are shown in drawings GEO_2722_1023_04 and GEO_2722_1023_05 respectively. The data has been displayed relative to a digital topographic survey base plan provided by the client as drawing ‘Church Farm Bishop Monkton 2D 2591.dwg'. The base plan was in the Ordnance Survey National Grid co-ordinate system and as the survey grids / data were referenced directly to National Grid co-ordinates the data could be simply superimposed onto the base plan in the correct position.
The geophysical anomalies have been categorised based on the type of response that they exhibit and an interpretation as to the cause(s) or possible cause(s) of each anomaly type is also provided. The interpretation of the geophysical datasets are displayed in drawing GEO_2722_1023_06. The geophysical interpretation drawing must be used in conjunction with the relevant results section and appendices of this report.
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3. RESULTS&DISCUSSION 3.1 Microgravity data Microgravity variations can indicate areas where the sub-surface density changes, relative to the surrounding ground / material. Density variations can relate to sub-surface features such as voids (where the density is lower), areas of fractured ground or infilled natural features (where the density may be slightly lower), or to general changes in sub-surface conditions, such as changes in depth to bedrock or the composition of the bedrock or superficial deposits (which can result in higher or lower sub-surface density). Some anthropogenic activity can cause density variations, such as areas of compacted ground (giving slightly denser ground) or mining activity (producing areas of low density similar to natural voids, fractured ground or infilled features). Areas of lower density produce low microgravity anomalies and areas of denser ground / material produce higher microgravity anomalies. The microgravity data at this site has slight variations with some areas of higher density and others of lower density but the majority of these are relatively weak and are not suggestive of solution features or voids. It is thought that the majority, if not all, of the responses are probably related to natural sub-surface variations (not related to gypsum dissolution) although it is possible that some of the density variations may be related anthropogenic activity at the site associated with recent or current land-use. This could include areas where the ground has been compacted or contains near-surface material that is different to the surrounding ground. Two areas of positive residual Bouguer anomalies have been shown on the interpretation where the responses are slightly more positive than the general background. These indicate areas of higher sub-surface density, compared to the majority of the site. They are possibly related to geological / pedological variations or areas of compacted ground and whilst their exact cause is not certain they will not be related to gypsum dissolution features. Three areas of negative residual Bouguer anomalies have been shown on the interpretation where the responses are slightly more negative than the general background. These indicate areas of lower sub-surface density, compared to the majority of the site. The smaller areas at the north-western edge of the survey area are too small to reliably interpret but they are probably related to features / variations beyond the survey area and are unlikely to relate to significant sub-surface variations beneath the site. The larger area in the north of the site (Anomaly A) is fairly regular in shape with a well-defined relatively straight edge to the south-west. The shape is not typical of a solution feature and it could be related to geological / pedological variations or an area where the ground is not as well-compacted as other parts of the site. However, the exact cause of the response is not certain and it does contain some stronger negative responses, which are of a similar magnitude to what may be obtained from of a solution feature. It should be recognised that a microgravity survey does not map gypsum deposits and the absence of low microgravity anomalies suggestive of voids does not mean that there is no gypsum beneath the site. Rather that there is no evidence in the microgravity data for significant voiding related to gypsum dissolution at the time of the survey. 3.2 Fixed frequency EM data Conductivity variations often reflect changes in sub-surface moisture content and can indicate areas that are waterlogged or contain higher amounts of moisture (higher conductivity) or which have lower moisture, such as bedrock or freely draining soils (lower conductivity). Anthropogenic (man-made) material, structures and features can produce strong conductivity responses, with metallic objects having very high or saturated conductivity response and
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brick or stone structures having low conductivity. Historic areas of subsidence in locations susceptible to gypsum dissolution tend to become infilled with peat deposits and these usually have higher moisture content than the surrounding soils and show as higher conductivity responses. Near-surface voids, if any were present, would have low conductivity values but it is very unlikely on this site that any voids would be present within the effective depth penetration of the EM (maximum of 3.5 m to 4.5 m below ground level). In-phase variations broadly relate to changes in the magnetic susceptibility of the soils or near-surface material. These can indicate the presence of infilled features or general changes in soil type across a site. Anthropogenic (man-made) material, structures and features can produce strong in-phase responses, with metallic objects having very high or saturated in- phase responses. Features that have been infilled over time with natural deposits, such as pits or areas of historic subsidence can have slightly increased in-phase responses. The EM data is relatively uniform but does show some variations across the survey area. There are several areas of relatively strong EM responses around the perimeter of the survey area. These will be related to adjacent above ground ferrous features, such as fences. There is a distinct area of slightly lower EM conductivity, compared to slightly higher conductivity areas around it. These differences will relate to sub-surface variations in moisture content. The edges to parts of the area, are relatively straight and regular, which could suggest that they are related to anthropogenic activity associated with recent or current land-use. They could indicate areas where the ground is better draining (slightly higher conductivity) compared to other areas. The EM variations at this site will not be related to gypsum dissolution.
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4. CONCLUSIONS The microgravity data at this site has slight variations with some areas of higher density and others of lower density. The majority of the responses will be caused by geological / pedological variations (not related to gypsum dissolution) or possibly anthropogenic activity. There is one negative microgravity anomaly that suggests the presence of an area of lower sub-surface density. The shape of the anomaly is not typical of a solution feature but the exact cause of the anomaly cannot be determined with certainty. Several strong EM anomalies are caused by adjacent ferrous objects, such as fences. The remaining EM anomalies are all thought to be caused by near-surface moisture variations, unrelated to gypsum dissolution features. Some of the variations could be caused by anthropogenic activity. It should be noted that a microgravity survey does not detect gypsum deposits. It can only identify voids or areas of significant density variations. The results of this survey cannot therefore be used to indicate the presence or absence of gypsum and it can only be taken to give an indication of sub-surface density variations at the time of the survey.
It should be noted that a geophysical survey does not directly locate sub-surface features - it identifies variations or anomalies in the background response caused by features. The interpretation of geophysical anomalies is often subjective and it is rarely possible to identify the cause of all such anomalies. Not all features will produce a measurable anomaly and the effectiveness of a geophysical survey is also dependant on the site-specific conditions. The main factors that may limit whether a feature can be detected are the composition of a feature, its depth and size and the surrounding material. It is not possible to guarantee that a geophysical survey will identify all sub-surface features. Confirmation on the identification of anomalies and the presence or absence of sub-surface features can only be achieved by intrusive investigation.
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REPRODUCED BY PERMISSION OF THE ORDNANCE SURVEY ON BEHALF OF THE CONTROLLER OF HER MAJESTY'S STATIONERY OFFICE. © CROWN COPYRIGHT. ALL RIGHTS RESERVED. LICENCE NUMBER 100047783.
SCALE SITE LOCATION 0m500m 1000m
Scale [A4 Sheet] Drawing Status NOTE AS SHOWN GEO_2722_1023_01 FINAL
THIS DRAWING AND THE INFORMATION CONTAINED Client THEREIN IS ISSUED IN CONFIDENCE AND IS THE COPYRIGHT OF PHASE SITE INVESTIGATIONS LIMITED. BWB CONSULTING LTD DISCLOSURE OF THIS INFORMATION TO THIRD PARTIES AND UNAUTHORISED COPYING OR REPLICATION OF THIS LEEDS DATA WITHOUT APPROVAL IS FORBIDDEN. Site CHURCH FARM BISHOP MONKTON
Title SITE LOCATION MAP Phase Site Investigations Ltd, 703A Whinfield Drive, Aycliffe Business Park, Newton Aycliffe, County Durham, DL5 6AU Job No T: +44 [0] 01325 311 751 GEO_2722_1023 E: [email protected] W: www.PhaseSI.com Drawn CA Chk. MW Date 31/10/2019 1 3. 3 ll MH (fw) = a CL 32.53 W
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0
0
.
.
0 7
7 5
3
.
3
7
3
3
7 l
. l
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Hedge o 8
T 3
0 0 . = 8 3
Grass
3
7
.
5 0 Tree Stone Height= Boundary
45.2 Wall
0
0
.
8
3
3
Grass 8
.
0
0 0
0
.
7 3
Top of Hedge
0
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5 40.59 0 .
.
7
8
8
.
3
0
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3
0
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Hradcore Predominantly Top of Hedge Direction of north Thorn Trees To 40.03 TP Hedge EM Hedge Extent Of Tree Canopy Woodland Height= 46.5 Tree LP Height= BS3 46.8 taken from drawing
CanopyOf
0
0
Sloe Bushes .
3 9
9
. 3 0
0 STN05
3 7
Concrete . 0 Hardcore
Hardstanding 0 'Church Farm Bishop Monkton 2D 2591.dwg' Track
For ElectricGate
0 Hedge
3 3 E
5 7 SP
R Canopy 6 .
L Hardcore .
. 0 7 Top of Hedge L
= 5 Track 0 = 3
0 3 39.42 3
3 7 6
8 . .
4 0 Tree . PEG4 9 2
0 Height= 7 48.3 Rev Date Drawn Chk. Description
SP Hedge
3 Canopy
8
. 3
0
7 Woodland . Predominantly 0
5 STN04 0 Thorn Macadam Hedge Grass 0 .0 Predominantly Grass 9 3 Trees To Thorn Extent Of Hedge SP - --/--/------
3 Woodland Top of Hedge
8 39.43 .
5 0
Top of Hedge 40.33 00 Tree 39. Height= 46.8 Top of Hedge Grass Macadam Hedge 38.86 Top of Hedge Canopy SP 0 40.16 36.5
.50 Tree 38 Height= Hardcore Predominantly 54.6 Track Thorn Hedge Predominantly 3 Thorn 6. Hedge 50 Tree Height= 42.4 TP
Top of Hedge Top of Hedge 39.22 38.85 Predominantly 00 Thorn 8. 3 Hedge 38 STN03 .50 Hedge Canopy 0 Top of.5 Hedge Tree 46.1037 Height= PEG1 45.1 Centreline Of Old Overgrown Hedge Top of Hedge Grass 45.34 .50 38
0 Tree .0 Height= 7 43.7 Top of Hedge 3 Phase Site Investigations Ltd, 703A Whinfield Drive, Aycliffe Centreline Of 40.25 Top of Hedge Old Overgrown 45.43 Hedge 36 .00 3 PEG3 8. Top of Hedge 00 Hedge Business Park, Newton Aycliffe, County Durham, DL5 6AU 39.49 Tree Canopy 50Height= 6. 42.4 Predominantly 3 Thorn Hedge 35 Hedge .50 Canopy 3 6.00 Predominantly T: +44 [0] 01325 311 751 Thorn Top of Hedge Hedge 44.15 0 38.0 Hedge Canopy 0 E: [email protected] Centreline Of .0 0 Old Overgrown 6 5 3 3 Macadam . 3 Hedge Tree 3 5.0 Top of Hedge 7 7. 4. 0 38.63 3 50 Top of Hedge Height= 50 Hardcore 44.70 47.8 Track W: www.PhaseSI.com
Hardcore Track
0 . 5 5 Top of Hedge 3 39.94 Grass 37 .50 Predominantly Thorn Hedge [A3 Sheet] 0 Status 0 Scale Drawing . 5 3
00 7. 3 Top of Hedge 39.73 0 .5 1:1000 GEO_2722_1023_03 FINAL BS2 4 3 Hedge Canopy Hedge E Canopy L PEG2 = 4 Centreline Of 0 Old Overgrown .4 0 3 37.0 Hedge Client Top of Hedge Centreline Of Pond Predominantly 43.85 Old Overgrown Thorn Hedge Hedge Grass 0 5 R . L 6 = 3 4 2 .0 3 50 BWB CONSULTING LTD . 36 Predominantly Top of Hedge Thorn 44.81 Hedge
Top of Hedge 36.50 38.80 LEEDS Top of Hedge BS1 38.66
0 Hardcore 36.0 Track Predominantly Thorn Hedge
3
6
. Site 0 0 0 0 . 6 3 CHURCH FARM
Hedge Canopy .50 35 BISHOP MONKTON Centreline Of Old Overgrown Hedge
Stock Electric Fence Stock Fence Title
5.00 MICROGRAVITY DATA 3 IL=34.48 RESIDUAL BOUGUER ANOMALY
0 .5 4 Electric 3 Stock Fence Predominantly Thorn Job No Hedge GEO_2722_1023
Surveyed CA,PW,MPDrawn NF Chk. MW Date 29/10/2019 1 3. 3 ll MH (fw) = a CL 32.53 W
FH f
150Ø IL 30.70 SP o 6
0 5 p
. 2 2 . SV 3 o 4 SV T 3 = NOTES MH Spire=58.22 CL 32.50 G Redundant? 4 Filled with Debris .8 0 WO STN02 4 M 0 1. THIS DRAWING MUST BE USED IN CONJUNCTION WITH = K .1 ll Stone L 2 LPM 2 a Boundary .2 m K 3 R 8 a = W Wall 3 d225Ø WM L f = a o 2 L c S p .0 Macadam E a Grass U o 3 M Verge I T 3 THE ACCOMPANYING REPORT (GEO_2722_1023_RPT L SB = = 25 3 IL 1 = .7 3 T8 1 = o SV .8 3 p
3 2 o 3 .PDF) WHICH PROVIDES DETAILS OF THE . f 37 W a Grass 3 . 88
ll Verge 0 7.
0 3
3 = 3 .
0 Tree L Stone 0 Height= E
Boundary 52.7 TECHNIQUES EMPLOYED, THEIR INHERENT
Wall Culvert
Parapet 3
m 3 .
a 5 e Tree Wall 0 tr Height= S 53.2 3
3 LIMITATIONS AND ANY SITE SPECIFIC ISSUES.
.
5
3
4 0 .
0 0
Hedge3
4
Canopy. 5 0
3 2. THIS DRAWING IS BASED UPON DRAWING 'Topo.dwg'
4 l
. l
0
3 a
0 5
. W
0 f 0 o 9 op .0 ll T 6 a PROVIDED BY THE CLIENT. 3 W = of p 6
o .7 3 6
T 3
4 = . 5
Post & Rail 0 Fence 3. PHASE SITE INVESTIGATIONS CANNOT ACCEPT Predominantly Thorn SP
Hedge
3 5
. Tree 0
Concrete 0 Height= RESPONSIBILITY FOR THE RELIABILITY OR ACCURACY
3 53.5
5
.
5
0 Tree
MH (fw?) 3
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. OF ANY INFORMATION PROVIDED BY A THIRD PARTY.
IL 33.08 0 54.2
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3
4
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5
. 5 5 0 0 Tree
100Ø Height=
3 45.9 5
. l
0 l 4. THIS DRAWING AND THE INFORMATION CONTAINED
0 a
3 W
6 f
. o 0
3 Trees To
5 0
. 5 0 p 0 .0
Extent Of o 8
Woodland T 3
3 = 6 . 0 Post &0 Rail THEREIN IS ISSUED IN CONFIDENCE AND IS THE
Fence 0 . 0 6 3 Tree Tree Top of Hedge Height= Height= 38.02 COPYRIGHT OF PHASE SITE INVESTIGATIONS LIMITED. 46.6 43.9 Stone Boundary
Wall 3
6
.
Concrete 5 DISCLOSURE OF THIS INFORMATION TO THIRD Predominantly 0
0
Thorn 5 .
Hedge 6
3 0
0
Trees To . 7
3
3 6
.
5 Extent Of 0 Woodland Tree Top of Hedge Height= PARTIES AND UNAUTHORISED COPYING OR 38.63 47.6 Woodland BS4
EP EM Predominantly 0
3 5 Thorn
. Hedge 6
6 . 5 REPLICATION OF THIS DATA WITHOUT APPROVAL IS
3 0
Hardcore Grass 3 7. Track 00 ll a FORBIDDEN. Stay f W o 9 p .2 o 8 Predominantly T 3 Thorn = Hedge
TP 3
5 ALWAYS EXERCISE CAUTION WHEN EXCAVATING
. 3
5
3
7 3 6
. 5 6
0 .
EM 5 0
0 SP
.
3
0
6
0 Tree .
5 Height=
0 46.8 Hedge Canopy 37 15 . 00 CanopyOf Top of Hedge Macadam N Sloe Bushes 40.60 Top of Hedge 3 7 mS/m 39.94 .0
Woodland 0
0 0
0
0
.
.
0 7
7 5
3
.
3
7
3
3
7 l
. l
0 a 0 Tree Height= W f 45.4 Predominantly o 1 1 Thorn p .
Hedge o 8
T 3
0 0 . = 8 3
Grass
3
7
.
5 0 Tree Stone Height= Boundary
45.2 Wall
0
0
.
8
3
3
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.
0
0 0
0
.
7 3
Top of Hedge
0
3 0
5 40.59 0 .
.
7
8
8
.
3
0
3 0
3
0
5 8
.
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Hradcore Predominantly Top of Hedge Direction of north Thorn Trees To 40.03 TP Hedge EM Hedge Extent Of Tree Canopy Woodland Height= 46.5 Tree LP Height= BS3 46.8 taken from drawing
CanopyOf
0
0
Sloe Bushes .
3 9
9
. 3 0
0 STN05
3 7
Concrete . 0 Hardcore
Hardstanding 0 'Church Farm Bishop Monkton 2D 2591.dwg' Track
For ElectricGate
0 Hedge
3 3 E
5 7 SP
R Canopy 6 .
L Hardcore .
. 0 7 Top of Hedge L
= 5 Track 0 = 3
0 3 39.42 3
3 7 6
8 . .
4 0 Tree . PEG4 9 2
0 Height= 7 48.3 Rev Date Drawn Chk. Description
SP Hedge
3 Canopy
8
. 3
0
7 Woodland . Predominantly 0
5 STN04 0 Thorn Macadam Hedge Grass 0 .0 Predominantly Grass 9 3 Trees To Thorn Extent Of Hedge SP - --/--/------
3 Woodland Top of Hedge
8 39.43 .
5 0
Top of Hedge 40.33 00 Tree 39. Height= 46.8 Top of Hedge Grass Macadam Hedge 38.86 Top of Hedge Canopy SP 0 40.16 36.5
.50 Tree 38 Height= Hardcore Predominantly 54.6 Track Thorn Hedge Predominantly 3 Thorn 6. Hedge 50 Tree Height= 42.4 TP
Top of Hedge Top of Hedge 39.22 38.85 Predominantly 00 Thorn 8. 3 Hedge 38 STN03 .50 Hedge Canopy 0 Top of.5 Hedge Tree 46.1037 Height= PEG1 45.1 Centreline Of Old Overgrown Hedge Top of Hedge Grass 45.34 .50 38
0 Tree .0 Height= 7 43.7 Top of Hedge 3 Phase Site Investigations Ltd, 703A Whinfield Drive, Aycliffe Centreline Of 40.25 Top of Hedge Old Overgrown 45.43 Hedge 36 .00 3 PEG3 8. Top of Hedge 00 Hedge Business Park, Newton Aycliffe, County Durham, DL5 6AU 39.49 Tree Canopy 50Height= 6. 42.4 Predominantly 3 Thorn Hedge 35 Hedge .50 Canopy 3 6.00 Predominantly T: +44 [0] 01325 311 751 Thorn Top of Hedge Hedge 44.15 0 38.0 Hedge Canopy 0 E: [email protected] Centreline Of .0 0 Old Overgrown 6 5 3 3 Macadam . 3 Hedge Tree 3 5.0 Top of Hedge 7 7. 4. 0 38.63 3 50 Top of Hedge Height= 50 Hardcore 44.70 47.8 Track W: www.PhaseSI.com
Hardcore Track
0 . 5 5 Top of Hedge 3 39.94 Grass 37 .50 Predominantly Thorn Hedge [A3 Sheet] 0 Status 0 Scale Drawing . 5 3
00 7. 3 Top of Hedge 39.73 0 .5 1:1000 GEO_2722_1023_04 FINAL BS2 4 3 Hedge Canopy Hedge E Canopy L PEG2 = 4 Centreline Of 0 Old Overgrown .4 0 3 37.0 Hedge Client Top of Hedge Centreline Of Pond Predominantly 43.85 Old Overgrown Thorn Hedge Hedge Grass 0 5 R . L 6 = 3 4 2 .0 3 50 BWB CONSULTING LTD . 36 Predominantly Top of Hedge Thorn 44.81 Hedge
Top of Hedge 36.50 38.80 LEEDS Top of Hedge BS1 38.66
0 Hardcore 36.0 Track Predominantly Thorn Hedge
3
6
. Site 0 0 0 0 . 6 3 CHURCH FARM
Hedge Canopy .50 35 BISHOP MONKTON Centreline Of Old Overgrown Hedge
Stock Electric Fence Stock Fence Title
5.00 3 IL=34.48 ELECTROMAGNETIC CONDUCTIVITY DATA
0 .5 4 Electric 3 Stock Fence Predominantly Thorn Job No Hedge GEO_2722_1023
Surveyed CA,JWDrawn NF Chk. MW Date 29/10/2019 1 3. 3 ll MH (fw) = a CL 32.53 W
FH f
150Ø IL 30.70 SP o 6
0 5 p
. 2 2 . SV 3 o 4 SV T 3 = NOTES MH Spire=58.22 CL 32.50 G Redundant? 4 Filled with Debris .8 0 WO STN02 4 M 0 1. THIS DRAWING MUST BE USED IN CONJUNCTION WITH = K .1 ll Stone L 2 LPM 2 a Boundary .2 m K 3 R 8 a = W Wall 3 d225Ø WM L f = a o 2 L c S p .0 Macadam E a Grass U o 3 M Verge I T 3 THE ACCOMPANYING REPORT (GEO_2722_1023_RPT L SB = = 1 3 IL 1 = .7 3 T8 1 = o SV .8 3 p
3 2 o 3 .PDF) WHICH PROVIDES DETAILS OF THE . f 37 W a Grass 3 . 88
ll Verge 0 7.
0 3
3 = 3 .
0 Tree L Stone 0 Height= E
Boundary 52.7 TECHNIQUES EMPLOYED, THEIR INHERENT
Wall Culvert
Parapet 3
m 3 .
a 5 e Tree Wall 0 tr Height= S 53.2 3
3 LIMITATIONS AND ANY SITE SPECIFIC ISSUES.
.
5
3
4 0 .
0 0
Hedge3
4
Canopy. 5 0
3 2. THIS DRAWING IS BASED UPON DRAWING 'Topo.dwg'
4 l
. l
0
3 a
0 5
. W
0 f 0 o 9 op .0 ll T 6 a PROVIDED BY THE CLIENT. 3 W = of p 6
o .7 3 6
T 3
4 = . 5
Post & Rail 0 Fence 3. PHASE SITE INVESTIGATIONS CANNOT ACCEPT Predominantly Thorn SP
Hedge
3 5
. Tree 0
Concrete 0 Height= RESPONSIBILITY FOR THE RELIABILITY OR ACCURACY
3 53.5
5
.
5
0 Tree
MH (fw?) 3
RL=40.60 CL 33.88 4 Height=
. OF ANY INFORMATION PROVIDED BY A THIRD PARTY.
IL 33.08 0 54.2
0 Woodland
3
4
. 3
5
. 5 5 0 0 Tree
100Ø Height=
3 45.9 5
. l
0 l 4. THIS DRAWING AND THE INFORMATION CONTAINED
0 a
3 W
6 f
. o 0
3 Trees To
5 0
. 5 0 p 0 .0
Extent Of o 8
Woodland T 3
3 = 6 . 0 Post &0 Rail THEREIN IS ISSUED IN CONFIDENCE AND IS THE
Fence 0 . 0 6 3 Tree Tree Top of Hedge Height= Height= 38.02 COPYRIGHT OF PHASE SITE INVESTIGATIONS LIMITED. 46.6 43.9 Stone Boundary
Wall 3
6
.
Concrete 5 DISCLOSURE OF THIS INFORMATION TO THIRD Predominantly 0
0
Thorn 5 .
Hedge 6
3 0
0
Trees To . 7
3
3 6
.
5 Extent Of 0 Woodland Tree Top of Hedge Height= PARTIES AND UNAUTHORISED COPYING OR 38.63 47.6 Woodland BS4
EP EM Predominantly 0
3 5 Thorn
. Hedge 6
6 . 5 REPLICATION OF THIS DATA WITHOUT APPROVAL IS
3 0
Hardcore Grass 3 7. Track 00 ll a FORBIDDEN. Stay f W o 9 p .2 o 8 Predominantly T 3 Thorn = Hedge
TP 3
5 ALWAYS EXERCISE CAUTION WHEN EXCAVATING
. 3
5
3
7 3 6
. 5 6
0 .
EM 5 0
0 SP
.
3
0
6
0 Tree .
5 Height=
0 46.8 Hedge Canopy 37 -0.1 . 00 CanopyOf Top of Hedge Macadam N Sloe Bushes 40.60 Top of Hedge 3 7 unitless 39.94 .0
Woodland 0
0 0
0
0
.
.
0 7
7 5
3
.
3
7
3
3
7 l
. l
0 a 0 Tree Height= W f 45.4 Predominantly o 1 1 Thorn p .
Hedge o 8
T 3
0 0 . = 8 3
Grass
3
7
.
5 0 Tree Stone Height= Boundary
45.2 Wall
0
0
.
8
3
3
Grass 8
.
0
0 0
0
.
7 3
Top of Hedge
0
3 0
5 40.59 0 .
.
7
8
8
.
3
0
3 0
3
0
5 8
.
. 6 5
3 0
Hradcore Predominantly Top of Hedge Direction of north Thorn Trees To 40.03 TP Hedge EM Hedge Extent Of Tree Canopy Woodland Height= 46.5 Tree LP Height= BS3 46.8 taken from drawing
CanopyOf
0
0
Sloe Bushes .
3 9
9
. 3 0
0 STN05
3 7
Concrete . 0 Hardcore
Hardstanding 0 'Church Farm Bishop Monkton 2D 2591.dwg' Track
For ElectricGate
0 Hedge
3 3 E
5 7 SP
R Canopy 6 .
L Hardcore .
. 0 7 Top of Hedge L
= 5 Track 0 = 3
0 3 39.42 3
3 7 6
8 . .
4 0 Tree . PEG4 9 2
0 Height= 7 48.3 Rev Date Drawn Chk. Description
SP Hedge
3 Canopy
8
. 3
0
7 Woodland . Predominantly 0
5 STN04 0 Thorn Macadam Hedge Grass 0 .0 Predominantly Grass 9 3 Trees To Thorn Extent Of Hedge SP - --/--/------
3 Woodland Top of Hedge
8 39.43 .
5 0
Top of Hedge 40.33 00 Tree 39. Height= 46.8 Top of Hedge Grass Macadam Hedge 38.86 Top of Hedge Canopy SP 0 40.16 36.5
.50 Tree 38 Height= Hardcore Predominantly 54.6 Track Thorn Hedge Predominantly 3 Thorn 6. Hedge 50 Tree Height= 42.4 TP
Top of Hedge Top of Hedge 39.22 38.85 Predominantly 00 Thorn 8. 3 Hedge 38 STN03 .50 Hedge Canopy 0 Top of.5 Hedge Tree 46.1037 Height= PEG1 45.1 Centreline Of Old Overgrown Hedge Top of Hedge Grass 45.34 .50 38
0 Tree .0 Height= 7 43.7 Top of Hedge 3 Phase Site Investigations Ltd, 703A Whinfield Drive, Aycliffe Centreline Of 40.25 Top of Hedge Old Overgrown 45.43 Hedge 36 .00 3 PEG3 8. Top of Hedge 00 Hedge Business Park, Newton Aycliffe, County Durham, DL5 6AU 39.49 Tree Canopy 50Height= 6. 42.4 Predominantly 3 Thorn Hedge 35 Hedge .50 Canopy 3 6.00 Predominantly T: +44 [0] 01325 311 751 Thorn Top of Hedge Hedge 44.15 0 38.0 Hedge Canopy 0 E: [email protected] Centreline Of .0 0 Old Overgrown 6 5 3 3 Macadam . 3 Hedge Tree 3 5.0 Top of Hedge 7 7. 4. 0 38.63 3 50 Top of Hedge Height= 50 Hardcore 44.70 47.8 Track W: www.PhaseSI.com
Hardcore Track
0 . 5 5 Top of Hedge 3 39.94 Grass 37 .50 Predominantly Thorn Hedge [A3 Sheet] 0 Status 0 Scale Drawing . 5 3
00 7. 3 Top of Hedge 39.73 0 .5 1:1000 GEO_2722_1023_05 FINAL BS2 4 3 Hedge Canopy Hedge E Canopy L PEG2 = 4 Centreline Of 0 Old Overgrown .4 0 3 37.0 Hedge Client Top of Hedge Centreline Of Pond Predominantly 43.85 Old Overgrown Thorn Hedge Hedge Grass 0 5 R . L 6 = 3 4 2 .0 3 50 BWB CONSULTING LTD . 36 Predominantly Top of Hedge Thorn 44.81 Hedge
Top of Hedge 36.50 38.80 LEEDS Top of Hedge BS1 38.66
0 Hardcore 36.0 Track Predominantly Thorn Hedge
3
6
. Site 0 0 0 0 . 6 3 CHURCH FARM
Hedge Canopy .50 35 BISHOP MONKTON Centreline Of Old Overgrown Hedge
Stock Electric Fence Stock Fence Title
5.00 3 IL=34.48 ELECTROMAGNETIC IN-PHASE DATA
0 .5 4 Electric 3 Stock Fence Predominantly Thorn Job No Hedge GEO_2722_1023
Surveyed CA,JWDrawn NF Chk. MW Date 29/10/2019 1 3. 3 ll MH (fw) = a CL 32.53 W
FH f
150Ø IL 30.70 SP o 6
0 5 p
. 2 2 . SV 3 o 4 SV T 3 = NOTES MH Spire=58.22 CL 32.50 G Redundant? 4 Filled with Debris .8 0 WO STN02 4 M 0 1. THIS DRAWING MUST BE USED IN CONJUNCTION WITH = K .1 ll Stone L 2 LPM 2 a Boundary .2 m K 3 R 8 a = W Wall 3 d225Ø WM L f = a o 2 L c S p .0 Macadam E a Grass U o 3 M Verge I T 3 THE ACCOMPANYING REPORT (GEO_2722_1023_RPT L = = SB 3 IL 1 = .7 3 T8 1 = o SV .8 3 p
3 2 o 3 .PDF) WHICH PROVIDES DETAILS OF THE . f 37 W a Grass 3 . 88
ll Verge 0 7.
0 3
3 = 3 .
0 Tree L Stone 0 Height= E
Boundary 52.7 TECHNIQUES EMPLOYED, THEIR INHERENT
Wall Culvert
Parapet 3
m 3 .
a 5 e Tree Wall 0 tr Height= S 53.2 3
3 LIMITATIONS AND ANY SITE SPECIFIC ISSUES.
.
5
3
4 0 .
0 0
Hedge3
4
Canopy. 5 0
3 2. THIS DRAWING IS BASED UPON DRAWING 'Topo.dwg'
4 l
. l
0
3 a
0 5
. W
0 f 0 o 9 op .0 ll T 6 a PROVIDED BY THE CLIENT. 3 W = of p 6
o .7 3 6
T 3
4 = . 5
Post & Rail 0 Fence 3. PHASE SITE INVESTIGATIONS CANNOT ACCEPT Predominantly Thorn SP
Hedge
3 5
. Tree 0
Concrete 0 Height= RESPONSIBILITY FOR THE RELIABILITY OR ACCURACY
3 53.5
5
.
5
0 Tree
MH (fw?) 3
RL=40.60 CL 33.88 4 Height=
. OF ANY INFORMATION PROVIDED BY A THIRD PARTY.
IL 33.08 0 54.2
0 Woodland
3
4
. 3
5
. 5 5 0 0 Tree
100Ø Height=
3 45.9 5
. l
0 l 4. THIS DRAWING AND THE INFORMATION CONTAINED
0 a
3 W
6 f
. o 0
3 Trees To
5 0
. 5 0 p 0 .0
Extent Of o 8
Woodland T 3
3 = 6 . 0 Post &0 Rail THEREIN IS ISSUED IN CONFIDENCE AND IS THE
Fence 0 . 0 6 3 Tree Tree Top of Hedge Height= Height= 38.02 COPYRIGHT OF PHASE SITE INVESTIGATIONS LIMITED. 46.6 43.9 Stone Boundary
Wall 3
6
.
Concrete 5 DISCLOSURE OF THIS INFORMATION TO THIRD Predominantly 0
0
Thorn 5 .
Hedge 6
3 0
0
Trees To . 7
3
3 6
.
5 Extent Of 0 Woodland Tree Top of Hedge Height= PARTIES AND UNAUTHORISED COPYING OR 38.63 47.6 Woodland BS4
EP EM Predominantly 0
3 5 Thorn
. Hedge 6
6 . 5 REPLICATION OF THIS DATA WITHOUT APPROVAL IS
3 0
Hardcore Grass 3 7. Track 00 ll a FORBIDDEN. Stay f W o 9 p .2 o 8 Predominantly T 3 Thorn = Hedge
TP 3
5 ALWAYS EXERCISE CAUTION WHEN EXCAVATING
. 3
5
3
7 3 6
. 5 6
0 .
EM 5 0
0 SP
.
3
0
6
0 Tree .
5 Height=
0 46.8 Hedge Canopy 3 7. 00 CanopyOf Top of Hedge Macadam N Sloe Bushes 40.60 Top of Hedge 3 39.94 7 .0
Woodland 0
0 0
0
0
.
.
0 7
7 5
3
.
3
7
3
3
7 l
. l
0 a 0 Tree Height= W f 45.4 Predominantly o 1 1 Thorn p .
Hedge o 8
T 3
0 0 . = 8 3
Grass
3
7
.
5 0 Tree Stone Height= Boundary
45.2 Wall
0
0
.
8
3
3
Grass 8
.
0
0 0
0
.
A 7 3
Top of Hedge
0
3 0
5 40.59 0 .
.
7
8
8
.
3
0
3 0
3
0
5 8
.
. 6 5
3 0
Hradcore Predominantly Top of Hedge Direction of north Thorn Trees To 40.03 TP Hedge EM Hedge Extent Of Tree Canopy Woodland Height= 46.5 Tree LP Height= BS3 46.8 taken from drawing
CanopyOf
0
0
Sloe Bushes .
3 9
9
. 3 0
0 STN05
3 7
Concrete . 0 Hardcore
Hardstanding 0 'Church Farm Bishop Monkton 2D 2591.dwg' Track
For ElectricGate
0 Hedge
3 3 E
5 7 SP
R Canopy 6 .
L Hardcore .
. 0 7 Top of Hedge L
= 5 Track 0 = 3
0 3 39.42 3
3 7 6
8 . .
4 0 Tree . PEG4 9 2
0 Height= 7 48.3 Rev Date Drawn Chk. Description
SP Hedge
3 Canopy
8
. 3
0
7 Woodland . Predominantly 0
5 STN04 0 Thorn Macadam Hedge Grass 0 .0 Predominantly Grass 9 3 Trees To Thorn Extent Of Hedge SP - --/--/------
3 Woodland Top of Hedge
8 39.43 .
5 0
Top of Hedge 40.33 00 Tree 39. Height= 46.8 Top of Hedge Grass Macadam Hedge 38.86 Top of Hedge Canopy SP 0 40.16 36.5
.50 Tree 38 Height= Hardcore Predominantly 54.6 Track Thorn Hedge Predominantly 3 Thorn 6. Hedge 50 Tree Height= 42.4 TP
Top of Hedge Top of Hedge 39.22 38.85 Predominantly 00 Thorn 8. 3 Hedge 38 STN03 .50 Hedge Canopy 0 Top of.5 Hedge Tree 46.1037 Height= PEG1 45.1 Centreline Of Old Overgrown Hedge Top of Hedge Grass 45.34 .50 38
0 Tree .0 Height= 7 43.7 Top of Hedge 3 Phase Site Investigations Ltd, 703A Whinfield Drive, Aycliffe Centreline Of 40.25 Top of Hedge Old Overgrown 45.43 Hedge 36 .00 3 PEG3 8. Top of Hedge 00 Hedge Business Park, Newton Aycliffe, County Durham, DL5 6AU 39.49 Tree Canopy 50Height= 6. 42.4 Predominantly 3 Thorn Hedge 35 Hedge .50 Canopy 3 6.00 Predominantly T: +44 [0] 01325 311 751 Thorn Top of Hedge Hedge 44.15 0 38.0 Hedge Canopy 0 E: [email protected] Centreline Of .0 0 Old Overgrown 6 5 3 3 Macadam . 3 Hedge Tree 3 5.0 Top of Hedge 7 7. 4. 0 38.63 3 50 Top of Hedge Height= 50 Hardcore 44.70 47.8 Track W: www.PhaseSI.com
Hardcore Track
0 . 5 5 Top of Hedge 3 39.94 Grass 37 .50 Predominantly Thorn Hedge [A3 Sheet] 0 Status 0 Scale Drawing . 5 3
00 7. 3 Top of Hedge 39.73 0 .5 1:1000 GEO_2722_1023_06 FINAL BS2 4 3 Hedge Canopy Hedge E Canopy L PEG2 = 4 Centreline Of 0 Old Overgrown .4 0 3 37.0 Hedge Client Top of Hedge Centreline Of Pond Predominantly 43.85 Old Overgrown Thorn Hedge Hedge Grass 0 5 R . L 6 = 3 4 2 .0 3 50 BWB CONSULTING LTD . 36 Predominantly Top of Hedge Thorn 44.81 Hedge
Top of Hedge 36.50 38.80 LEEDS Top of Hedge BS1 38.66
0 Hardcore 36.0 Track Predominantly Thorn Hedge
3
6
. Site 0 0 0 0 . 6 3 ANOMALY TYPE INTERPRETATION CHURCH FARM Hedge Canopy .50 35 BISHOP MONKTON Centreline Of Old Overgrown AREA OF HIGHER SUB-SURFACE DENSITY. POSSIBLE GEOLOGICAL / Hedge POSITIVE RESIDUAL BOUGUER PEDOLOGICAL VARIATION OR AREA WHERE MATERIAL IS MORE COMPACTED Stock Electric Fence Stock MICROGRAVITY ANOMALY (COMPARED TO THE REST OF THE SITE) BUT THE EXACT CAUSE OF THE Fence Title ANOMALY IS NOT CERTAIN. WILL NOT RELATE TO GYPSUM DISSOLUTION
5.00 AREA OF LOWER SUB-SURFACE DENSITY. POSSIBLE GEOLOGICAL / 3 IL=34.48 NEGATIVE RESIDUAL BOUGUER PEDOLOGICAL VARIATION OR AREA WHERE MATERIAL IS LESS COMPACTED INTERPRETATION OF GEOPHYSICAL DATA MICROGRAVITY ANOMALY (COMPARED TO THE REST OF THE SITE) BUT THE EXACT CAUSE OF THE
0 .5 4 ANOMALY IS NOT CERTAIN Electric 3 Stock Fence Predominantly Thorn Job No AREA OF RELATIVELY STRONG EM Hedge PROBABLY RELATED TO ADJACENT ABOVE GROUND FERROUS FEATURE GEO_2722_1023 RESPONSE PROBABLY CAUSED BY VARIATIONS IN SUB-SURFACE MOISTURE CONTENT. AREA OF SLIGHTLY LOWER EM Surveyed Drawn MAY BE RELATED TO ANTHROPOGENIC ACTIVITY. WILL NOT RELATE TO MW,CA,PW,JW MW CONDUCTIVITY GYPSUM DISSOLUTION Chk. NF Date 29/10/2019 Church Farm, Bishop Monkton Geophysical survey
REFERENCES British Geological Survey, 2019, online resource - www.bgs.ac.uk Environment Agency, 2019, online resource - enviornment.data.gov.uk
Sharma, P.V. 1997, Environmental and engineering geophysics, Cambridge University Press
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APPENDIX 1 1. Microgravity surveys: technical information 1.1 Theoretical background 1.1.1 Gravity surveys measure variations in the earth’s gravitational field (specifically changes in the acceleration due to gravity) and have been used to identify large scale geological variations and features since the early part of the twentieth century. Over the last couple of decades improving equipment sensitivity has enabled small localised variations to be detected which allows the technique to be used for engineering and environmental applications. To detect features on this local scale instrumentation that is capable of measuring the Earth’s acceleration due to gravity (g) to 1 part in 1 billion is required. These are termed microgravity surveys as the variations are usually measured in micro Gals (µGal). 1.1.2 If the main constituents that make up the Earth’s gravity field are broken down it can be seen exactly how accurate the instrumentation and procedure for acquiring gravity needs to be. 1.1.3 The total acceleration due to the Earth’s gravity is approximately 983 Gals which is ~983,000,000 µGal. The mass of the Earth accounts for ~974,899,700 µGal. The equatorial radius of the Earth is 21 km greater than the polar radius which contributes ~5,000,000 µGal. The difference in elevation between the highest mountains and the deepest oceans contributes ~3,000,000 µGal. A further ~100,000 µGal is accounted for by regional geology and crustal structure. The remaining several hundred µGal are the values that are measured in a microgravity survey and these are due to changes in the near-surface geology, including variations caused by sub-surface features, coupled with effects from the sun and the moon which can vary rapidly during the course of a day by 100 to 200 µGal. 1.1.4 There are a number of ways that these small variations in the acceleration due to gravity can be measured. The most common method, for microgravity surveys, involves suspending a mass on a spring between two capacitors. The mass is supported by the electrostatic repulsion of the capacitor and is allowed to move upwards or downwards by the spring. When changes in gravity cause the mass to move fractionally, either down or up, this causes a change in capacitance which can be measured. This change in capacitance is directly proportional to the change in gravity. This system requires instrumentation with highly complex and temperature stable electronics. 1.1.5 As well as having to accurately measure these very small variations a microgravity survey must also take into account a large number of variables before the measured value can be converted into useable data which can allow the comparison of gravity variations across a site. During the course of a survey the instrument will drift due to the elastic properties of the spring. As mentioned above the movement of the sun and the moon have an effect on g and this affect varies during the course of a day. The latitude and altitude of a survey need to be taken into account and if the height of survey stations varies within a survey then these must also be allowed for when determining relative sub-surface gravity values. The density of the material beneath a survey area and the effects of surface features also affect the measured value. Details of how these factors can be corrected for are presented in Section Error! Reference source not found.. 1.1.6 Finally there are a number of factors that contribute to ‘noise’ which can reduce data quality and must be kept to a minimum. These include vibrations from passing vehicles (or even pedestrians walking in close proximity to the instrument), wind and other industrial activity which can all vibrate the instrument sufficiently to cause variations in the data measurements.
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The instrument must be kept level when taking a reading and slight tilts during the measurement process can also detrimentally affect the data quality. 1.1.7 It can be seen that when measuring such small values which have a number of variables that must be accounted for that that good data collection is paramount. The quality and reliability of the interpretation of the data is limited by the quality of the raw data. 1.2 General survey methodology 1.2.1 The following general survey methodology was adopted unless otherwise stated in the survey report. 1.2.2 The microgravity survey will be carried out using a Scintrex CG-6 microgravity meter. The CG-6 is an automated gravity meter with a resolution of 1µgal. 1.2.3 Gravity measurements are usually acquired on a regular grid with survey stations set up at predetermined points along the grid. The grid spacing determines the resolution of the survey and is dependent on the survey objectives. Increasing the concentration of data points increases the resolution of the survey, as well as the associated survey time and costs. Forward modelling of a-priori data can optimise the survey procedure by establishing the survey grid resolution needed to detect the survey target with the minimum of data points. 1.2.4 Gravity measurements can be acquired along a single profile. However, the interpretation of the data is limited as it is not possible to determine whether the source of an anomaly is located in the same plane as the profile or to the side. 1.2.5 A base station is established in a quiet, stable, sheltered area. Readings are taken at this position at the start and end of the survey and also at regular intervals (between 1 hour and 1.5 hours) during the course of the survey. A minimum of five readings should be taken at each base station visit. 1.2.6 In between the base station readings the survey stations are occupied in sequence. It is important that the instrument is level at each survey station and remains so throughout the measuring process. Environmental effects such as boggy terrain and soft tarmac can cause the instrument to tilt and result in a false value being recorded and so extra care and should be taken in such areas. If tilts do occur then multiple readings may need to be taken at each point to ensure that the measured values are consistent. 1.2.7 Each station should be occupied for between 60 and 90 seconds and an average value for the readings during that time will be recorded. 1.2.8 As a matter of course repeat readings should be taken at a number of stations, regardless of the terrain conditions, to ensure that the values are consistent and repeatable and to check that no unforeseen factors are adversely affecting the data quality. Extraneous activities such as weather or urban noise may reduce the data quality and whilst these may be beyond the control of the survey a check of the data quality needs to be carried out to determine the reliability of the data. 1.2.9 Between 5% and 10% of the survey stations should be reoccupied (more in some terrains) to determine the repeatability of the data. If there is a large difference between the repeat readings then the overall reliability and quality of the data decreases and if this is too high then some types of features may not be identifiable. Repeat readings within 3 μGal to 5 μGal of the original value indicate high quality data. 1.2.10 Each survey station must be accurately recorded in both plan and elevation, relative to the base station, to allow accurate processing of the data. This will be done by tying in each
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station using a GNSS with an epoch of 10 (the higher epoch was used to increase the level accuracy to within 0.01 m). 1.3 Data processing, presentation and interpretation 1.3.1 As discussed above the measurements recorded by the microgravity meter are subject to several external effects that are not related to the sub-surface geology or features. For a valid geophysical interpretation to be made these effects must first be removed. The process of correcting for these effects is a well-established routine in any gravity survey and is often called the reduction of data. The necessary corrections are (1) free-air correction, (2) Bouguer correction and if the survey area requires it (3) terrain correction. As well as the above corrections, the instrument itself must be corrected for internal drift and Earth tides. Free air correction (FAC) This correction takes into account the vertical decrease in gravity with increased elevation. The correction is based on the inverse square dependence of the acceleration due to gravity on the distance from a datum plane. Bouguer correction (BC) The free air correction accounts solely for the variation in height between gravity points. The Bouguer correction accounts for the attraction of material between a reference height and that of the gravity station. This can be approximated by treating the intervening rock material as an infinite horizontal slab, of a thickness equal to the elevation difference, h, between the reference base and the gravity station. Terrain correction The Bouguer correction makes the assumption that the topography around the gravity station is flat. This is rarely the case and for areas with significant relief a further correction, the terrain correction, is needed. A hill rising in the vicinity of a gravity station will tend to have an upward attraction due to the extra mass contained in the hill. This will have the effect of reducing the measured value of gravity. Similarly a valley below the gravity station will also tend to reduce the measured value of gravity. In this case it is the missing mass within the valley that reduces the expected attraction due to gravity. There are several methods used for calculating the terrain correction including the Hammer, Plouff and Parker Methods. The most suitable method is selected depending on the character of the site. Drift correction The zero length spring used in the gravity instruments experience gradual change in reading with time. This drift is a result of the imperfect elasticity of the springs, which undergo an elastic creep with time and are unrelated to gravity changes. The correction for instrument drift is very simple and is based on repeated readings at a base station at recorded times throughout the day. A sample time between base station readings of one hour is normally used and the drift within this time is assumed to be linear. Tidal correction As well as the above effects, gravity measured during a survey varies with time because of periodic variation in the gravitational effects of the Sun and Moon associated with their orbits. In a high precision survey these effects must be corrected for. There is a small but measurable gravitational effect of up to 240 µgal, changing with time at a maximum rate of 50 µGal/hr at the Earth’s surface due to its spin and the relative motion of the sun and the moon. It is possible to predict the Earth tides using Longman’s formula but ideally it is advisable to record gravity continuously for at least a full day in the field location to check the prediction method used. 1.3.2 The results of the microgravity survey will be presented as a 2D contour plot, overlain onto to the digital map base. Anomalies of interest will be highlighted on a separate drawing and discussed in the accompanying report. The interpretation is made based on the type, size, strength and morphology of the anomalies, coupled with the available information on the site conditions. Each type of anomaly is displayed in separate, easily identifiable layers annotated
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as appropriate. The report and drawings will be provided in both hardcopy and digital formats. 1.4 Limitations of microgravity surveys 1.4.1 The data collection quality must be high. Slight errors in data collection can significantly reduce the effectiveness of a survey. 1.4.2 A microgravity survey requires the operator to accurately balance the instrument in a stable position for the duration of the reading. The presence of an uneven or unstable ground surface can reduce the data quality and dense, high or mature vegetation or surface obstructions may mean that some areas cannot be surveyed. 1.4.3 If data is too ‘noisy’ due to site and weather conditions then it may not be possible to identify features that produce weak anomalies. 1.4.4 Each type of material or feature beneath a point contributes to the gravity value measured at that point and so unless the probable sub-surface conditions are known then reliable interpretation of microgravity data is very difficult. Any given anomaly can also have a large number of possible causes. A small, shallow feature can produce the same response as a large, deep one and likewise features of different sizes and depths but which have different densities can all produce the same type of response. 1.4.5 Complex geologies and variations in sub-surface material across a site can make interpretation of the data more difficult and may require additional information on the site conditions to enable a reliable interpretation to be made. 1.4.6 To help in interpreting the data a sufficiently large enough area should be surveyed to enable the ‘background’ density, caused by the natural geology, to be determined which can allow any variations from this to be identified. Unfortunately the size of the area that needs to be covered to determine the background gravity values is dependent on the site specific conditions, particularly how complex the geology is, and so it is often not possible to determine what size area should be covered. 1.4.7 The depth at which features can be detected will vary depending on their composition, size and the surrounding material. 1.4.8 Surface features such as buildings and rapid changes in topography can have a detrimental effect on data quality. 1.4.9 A microgravity survey does not directly locate sub-surface features - it identifies variations or anomalies in the background readings caused by features. It can be possible to interpret the cause of anomalies based on the size, shape and strength of response but it should be recognised that a microgravity survey produces a plan of reduced gravity variations and not a plan of all sub-surface features. Interpretation of the anomalies is often subjective and it is rarely possible to identify the cause of all of the anomalies. 1.4.10 Anomalies identified by a microgravity survey are located in plan. It is not usually possible to obtain reliable depth information on the features that cause the anomalies unless there is supporting evidence on the anticipated size, density and depth of features. 1.4.11 Not all sub-surface variations will produce a measurable response and the effectiveness of a microgravity survey is also dependant on the site-specific conditions. It is not possible to guarantee that a microgravity survey will identify all sub-surface features. 1.4.12 The best way to substantiate the interpretation of the microgravity data is to include a second method in the process of interpretation. In this way, techniques that use different
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characteristics of the sub-surface can be used to supplement one another. If lithological knowledge can be provided from drilling logs or seismic data, then the geophysicist can have a high degree of confidence in their interpretation. 1.4.13 The microgravity technique is a guide to the sub-surface density distribution. Its primary aim is to target intrusive investigation by identifying anomalous areas. Once ground truth has been established, interpretations can be extrapolated across the site. Microgravity and geophysics in general, should not be viewed as an alternative to intrusive investigation but as a supplementary tool. Preliminary geophysical investigations have the potential to improve the success of an intrusive investigation as well as dramatically reduce its cost.
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APPENDIX 2 2. Fixed frequency electromagnetic surveys: technical information 2.1 Theoretical background 2.1.1 A fixed frequency EM instrument works by transmitting an electromagnetic field (the primary field) at a set frequency from a coil. The field interacts with surrounding materials and can produce eddy currents within electrical conductors. These currents cause a secondary electromagnetic field to be produced. A receiver coil measures this secondary field, along with the original field, and by separating the field out into components two different properties can be measured. The quadrature component provides a measure of the apparent ground conductivity whilst the in-phase component varies if metallic objects are present. 2.1.2 For an EM survey to be effective the target object must have a different electrical conductivity from the background material. This difference must be significant enough to produce a measureable anomaly relative to the background values, which can vary depending on the site-specific conditions. The main factors that may limit whether a feature can be detected are the composition of a feature, its depth and size and the surrounding material. 2.1.3 The depth of penetration that can be achieved is dependent on a number of factors including the ground conductivity, the size and composition of the target feature, the spacing between the coils and the orientation of the coils. There are a number of fixed frequency EM instruments available which, due to their different intercoil spacings, have depth penetration ranges from 0.75 m below ground level to up to 60 m below ground level. As with most geophysical techniques the resolution decreases with depth penetration. Instruments that can only penetrate to 0.5m have very good resolution and can detect relatively small features whilst those that can penetrate deeper may only be able to identify large scale features, such as geological faults or landfill extents. 2.1.4 The EM survey method is sensitive to interference from surface and near-surface conductive contaminants’. Surface features such as metallic fencing, parked vehicles, buildings or walls all have strong electromagnetic signatures that can dominate readings collected adjacent to them. Identification of anomalies caused by sub-surface features is therefore more difficult, or even impossible, in the vicinity of surface conductive features. The presence of made ground also has a detrimental effect on the EM data quality as this can contain conductive material in the form of metallic debris or waterlogged material. Identification of features beneath made ground is still possible if the target feature is reasonably large and has a strong electromagnetic response, although the depth penetration is likely to be reduced. Smaller features or electromagnetically weak features may not be identified. 2.1.5 The interpretation of EM anomalies is often subjective and it is rarely possible to identify the cause of all of the anomalies. It is not possible to guarantee that an EM survey will identify all sub-surface features. 2.1.6 Features that are commonly located using fixed frequency EM surveys include buried foundations or structures, mineshafts, voids, metallic pipes, underground storage tanks, geological features (such as faults and changes in strata), landfill extents and buried piles and pile caps. 2.2 Instrumentation 2.2.1 A Geonics EM31 with data logger was used for the EM survey. The Geonics EM31 has an intercoil spacing of 3.7 m, which yields a maximum effective depth penetration of 5 m when used in vertical mode.
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2.3 Survey methodology 2.3.1 The survey grid was established and tied-in using VRS RTK GNSS. Intermediate grid points were established using tape measures. The survey was undertaken as close to the boundaries as was possible given the site conditions and limitations of the equipment. 2.3.2 The survey was carried out with data collected on parallel profiles aligned broadly north to south. A GNSS was linked directly to the datalogger and each data point was referenced to UTM co-ordinates. These were converted direct to Ordnance Survey co-ordinates using the UK OSTN 02 projection. Each profile was spaced 2 m apart and a reading was taken at the equivalent of at least 0.5 m increments. Simultaneous readings of conductivity and in-phase were measured with the instrument in vertical mode. 2.3.3 The instrument was balanced and ‘zeroed’ at a base station that was established in a ‘quiet’ position (one which has a uniform background of EM values) on site. 2.4 Data processing, presentation and interpretation 2.4.1 The data was downloaded from the instrument at the end of each day’s survey, usually using bespoke software specific to the instrument. The data from each day was converted to a spreadsheet format and edited to remove header files and to insert the profile numbers so that the data could be read as an “xyz” file. 2.4.2 The EM data was analysed over a range of values using plots of the conductivity and in-phase datasets. A plot of the conductivity data has been shown in the report as this best highlights the anomalies that have been identified. The data was exported from the gridding software in .png format and then imported into AutoCAD direct to Ordnance Survey National Grid (OSNG). 2.4.3 The interpretation is made based on the type, size, strength and morphology of the anomalies, coupled with the available information on the site conditions. Each type of anomaly is displayed in separate, easily identifiable layers annotated as appropriate. 2.5 Limitations of EM surveys 2.5.1 The EM survey method requires the operator to walk over the site. The presence of an uneven ground surface, dense, high or mature vegetation or surface obstructions may mean that some areas cannot be surveyed. 2.5.2 The depth at which features can be detected will vary depending on their composition, size, the surrounding material and the type of instrument used for the survey. In good conditions large, near-surface conductive targets, such as mineshafts, buried drums or tanks, can be located at depths of up to 5 m. Smaller targets, such as buried foundations or archaeological features can be located at maximum depths of between 3 m and 5 m. 2.5.3 The EM survey method is sensitive to interference from surface and near-surface conductive ‘contaminants’. Surface features such as metallic fencing, parked vehicles, buildings or walls all have strong electromagnetic signatures that can dominate readings collected adjacent to them. Identification of anomalies caused by sub-surface features is therefore more difficult, or even impossible, in the vicinity of surface conductive features. 2.5.4 The presence of made ground also has a detrimental effect on the EM data quality as this can contain conductive material in the form of metallic debris or waterlogged material. Identification of features beneath made ground is still possible if the target feature is reasonably large and has a strong EM response, although the depth penetration is likely to be reduced. Smaller features or electromagnetically weak features may not be identified.
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2.5.5 An EM survey does not directly locate sub-surface features - it identifies variations or anomalies in the background readings caused by features. It can be possible to interpret the cause of anomalies based on the size, shape and strength of response but it should be recognised that an EM survey produces a plan of electromagnetic variations and not a plan of all sub-surface features. Interpretation of the anomalies is often subjective and it is rarely possible to identify the cause of all of the anomalies. 2.5.6 Anomalies identified by an EM survey are located in plan. It is not usually possible to obtain reliable depth information on the features that cause the anomalies. 2.5.7 Not all features will produce a measurable response and the effectiveness of an EM survey is also dependant on the site-specific conditions. It is not possible to guarantee that an EM survey will identify all sub-surface features. An EM survey is usually most-effective at identifying sub-surface features when used in conjunction with other complementary geophysical techniques.
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APPENDIX B SITE PLAN AND HISTORICAL SUBSIDENCE HOLLOW MAP
www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
APPENDIX C DR COOPERS REPORT
www.geoinvestigate.co.uk April 2021 The geological investigation of Boreholes 1 and 2 at Bishop Monkton near Ripon
Client: Geoinvestigate Site: Bishop Monkton south of Ripon Ref: Date: 22nd March 2021
Commercial in confidence
Location of boreholes south of Bishop Monkton courtesy of Open street map 2021
Report prepared by Dr Anthony H. Cooper FGS, C.Geol, EurGeol Independent Consulting Geologist & Evaporite Karst specialist
54 Church Lane Long Clawson Melton Mowbray Leicestershire LE14 4ND
Tel. +44 (-0) 1664 822358 Mb. +44 (-0) 7949 591957 E-mail [email protected] Profile: uk.linkedin.com/in/anthonyhcooper/ Page intentionally blank
1 Executive summary
This report reports on the geological logging of boreholes 1 and 2 drilled for Geoinvestigate at Bishop Monkton south of Ripon. The national grid references derived from the supplied Google image and GIS interrogation are for Borehole 1- 432872,465828 and for Borehole 2- 432852,465908. These NGR’s need confirming by Geoinvestigate.
The two boreholes show similar sequences with superficial deposits to a depth of around 15.00 m. Beneath this both prove the Brotherton Formation dolostone/ dolomitic limestone, but it is indicated to be broken and recovery was poor. In addition, borehole 2 included material collapsed or washed in from above suggesting a complex collapse, possibly into a sinkhole; this made the Brotherton Formation appear locally thicker.
Beneath the Brotherton Formation the strata of the Edlington Formation was largely brecciated or dissolution residues in borehole 1 and partially brecciated in borehole 2. In borehole 1 all the gypsum had nearly all dissolved and in borehole 2 about 1.80 m of gypsum remains in the sequence. Depending on the groundwater flow this has the potential to dissolve and there is some evidence of dissolution in ground adjacent to the site where a pond has enlarged in size over the past 100 years or so.
Both boreholes penetrated the limestones of the Cadeby Formation, the geological unit that in general supplies water under artesian pressure to the overlying strata forming the mechanism for gypsum dissolution.
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3 Table of Contents
Executive summary...... 2 Table of Contents...... 4 Terms of reference...... 5 Location...... 6 Method used to log the boreholes...... 7 Detailed log of Bishop Monkton Borehole 1 ...... 8 Detailed log of Bishop Monkton Borehole 2 ...... 10 Photographs of Bishop Monkton Borehole1...... 13 Photographs of Bishop Monkton Borehole 2...... 42 Discussion about the boreholes and local geology ...... 74 References...... 78
4 Terms of reference
This report has been prepared by Dr Anthony Cooper FGS, C.Geol, EurGeol, independent geological consultant, formerly of the British Geological Survey. He has 44 years of experience in the investigation of gypsum, gypsum dissolution and sinkhole subsidence related to evaporitic rocks. The brief for this report was to geologically log and report on the geological features of 2 boreholes drilled at Bishop Monkton, south of Ripon.
5 Location
Figure 1. Location diagram supplied by Geoinvestigate air photo courtesy of Google Copyright 2020
Figure 2. Location of boreholes south of Bishop Monkton. Topography courtesy of Open Street Map 2021
The grid references derived from the supplied Google image are for Borehole 1 432872,465828 and for Borehole 2 432852,465908. These NGR’s need confirming by Geoinvestigate.
6 Method used to log the boreholes
The boreholes were logged using traditional methods. Hard lithologies were broken with a hammer, soft lithologies were cut with a knife or a 50 mm wide square ended pointing trowel paring them down to a near-flat surface. Broken and cut surfaces were examined with a hand lens and some problematic lithologies were examined beneath a binocular microscope. Dilute (10%) hydrochloric acid (https://www.apcpure.com/product/hydrochloric-acid-10/) was used on many lithologies to determine if limestone was present. A knife and copper wire were used to assess the relative harnesses of the rocks. Photographs of the core complete in boxes and as close-up images were taken.
Photographs of the complete core boxes were taken with a camera and lighting held perpendicularly above the core boxes by using a ladder gantry. The complete core was photographed with a Nikon D7200 camera and 35mm f1.8 lens set at f8. An SB900 flash unit was used with a 25cm softbox and this fired a Elinchrom 400fx studio flash with a 60cm softbox. The flash was set up with manual settings and the combination gave a fairly even lighting. For the close up pictures a Nikon D7100 camera and 105mm Sigma macro lens mainly with a SB200 macroflash was used. In some instances, the softbox lighting was used instead and, in some others, oblique side lighting was used to reduce reflections. The images were taken as jpg and RAW and processed from RAW in Photolab saving the resultant images as jpgs.
For this report the written descriptions of the complete boreholes are presented first and then the images with notation describing the close-up images and the details contained within them. Finally, a discussion of the borehole content and comparison with the surrounding area is presented.
7 Detailed log of Bishop Monkton Borehole 1 NGR 432872, 465828
The upper part of this hole is described from drillers logs, the recovered core is described in detail.
Description of lithological unit Depth Thick- base ness (m) (m) Boulder clay (driller’s description) 10.00 10.00 Grey clay (driller’s description) 12.10 2.10 Sand and gravel (driller’s description) 13.00 0.90 Brown clay (driller’s description page 2) or Sand and gravel (driller’s 15.00 2.00 description page 3) No return (driller’s description page 2) or Limestone broken hard (driller’s 17.00 2.00 description page 3) N.R. BKG (driller’s description) - no returns, broken ground? 18.50 1.50 No description 19.00 0.50 Limestone cobbles 1.50m to 20.50; Limestone clay white 1.50m to 22.00 23.50 4.50 Limestone broken 1.50m to 23.50 (driller’s description) Very poor recovery c. 1.10m out of 4.50m about 25%. Recovered material about 80% Dolomite, light yellowish brown to brownish white very fine-grained to silty and clayey, appears to have been mainly a soft silty clay (weathered dolomite) that has washed away during drilling. About 20% of the recovered material was Limestone, medium grey, coarse to fine grained occurring in thin and very thin beds. The limestone fizzed well with dilute HCl. The dip on one bed was about 15 degrees, but another piece was heavily redrilled. No recovery 25.00 1.50 Dolomitic silt and clay, light yellowish brown and brownish white, slightly 28.00 2.00 calcareous. From the presence of thumb prints in the core this material was largely recovered as a very soft clay. At about 27.00 there was 0.06m of re-drilled very fine-grained porcelaneous dolostone. Below this about 0.50m recovery of similar materials to those above Drillers recorded problem with casing that needed reinstalling at about 28.00. The recovered material here included about 0.30 of sand, medium to coarse-grained with dolomitic clay. The sand comprised fine to coarse angular to subangular grey limestone and some quartz, plus abundant dolostone. None of this material was considered to be in situ. Limestone medium grey and yellowish brown on outside, thin and very 29.00 1.00 thin-bedded plus dolomitic limestone, light yellowish-brown present as fragments. Very poor recovery 0.40 in 1.90m of drilling, described by drillers as broken limestone. Clay, light yellow-brown presumably very soft, now dried hard. Abundant 29.90 0.90 angular clasts of similarly-coloured dolostone and medium grey mudstone. About 0.30 recovery out of 0.90m, drillers indicate no recovery from 29.00 to 30.00, but this material suggests some was boxed. Possible cavity or soft material over collapsed material? Clay with breccia, dark grey with c 30% passing down to 10% light 30.30 0.40 yellowish brown dolostone fragments and soft debris plus a little red- brown clay and grey clay clasts. Collapse breccia, distorted at base with mixed with red and brown clay. Clay, red-brown, sandy near top passing down into very stiff clay with 30.95 0.65 irregular laminae of grey clay and scattered dolostone fragments that are a bit more abundant near the base. Collapse breccia. Clay, red-brown, very stiff with slight colour banding, dip c 10 degrees, 31.50 0.55 scattered very fine gypsum crystals and a slight vein, a little brecciation in places, especially at base in core plug, thought some of this may be 8 broken by drilling? Assuming the poor recovery is in this interval 0.25m out of 0.79m with 32.29 0.79 recovery at base? Clay breccia, red-brown with slight banding, dip 40 degrees with patches of red-brown silt and a few angular breccia fragments of gypsum plus a little gypsum “sand” comprising small crystals remaining after dissolution of fibrous gypsum? Junction with unbrecciated rock below. Clay, red-brown with layers of fine 32.45 0.16 to coarse gypsum fragments and crystals remaining after the weathering of fibrous gypsum veins? Transition to less weathered rock below. Clay, red-brown with stringers 32.88 0.43 and nodules of white and light pinkish brown weathered very soft gypsum, plus laminae of red-brown and dark grey clay. 0.03 of weathered gypsum at base. Gypsum, light grey and white, nodular, possibly fragmented in a light red- 33.03 0.15 brown gypsiferous mudstone matrix. Core partly re-drilled, may initially have been soft, but now dried out, judging from the core lifter marks. Clay, medium red-brown, banded in laminae and thick laminae of light 33.60 0.57 pinkish brown silt and clay with at 33.50 a 0.01m bed of soft light pinkish brown silt. Layering sub-horizontal representing in-situ weathering of mudstone and gypsum? Limestone, light grey very fine-grained crystalline mainly hard and 34.20 0.60 compact in very thin (0.02) to thin (0.10) beds. About 20% red-brown mudstone weathered to hard clay. At 33.90 about 0.20 of fragmented white weathered gypsum. All the limestone fizzes well with acid. Clay, medium red-brown very stiff, weathered mudstone with laminae in 35.00 0.80 places of weathered calcareous silt forming about 5% of the rock. One cross-cutting 0.003 calcite vein. All highly weathered. No recovery 35.50 0.50 Poor recovery, 0.40 out of 1.50. Mudstone, silty, medium red-brown, 36.50 1.00 mottled brownish grey in place in top 0.30 becoming what was very soft clay at base, but which is now solid. Bottom 0.09 with mark of core lifter, grey and reddish-brown laminated mudstone (0.04) on medium, dark and light grey distorted mudstone, possibly distorted by drilling Top 0.05 partly redrilled and damaged by drilling. Breccia, medium brown 37.34 0.84 and reddish brown with about 20% grey hard clay/soft mudstone clasts all angular and many distorted ranging from a few millimetres to several centimetres across; some distorted steeply dipping (c.45 degrees) laminae and very thin beds of mudstone/clay Breccia, composed of mudstone and clay with scattered gypsum grains, 38.00 0.66 brown and reddish-brown mottled grey in places. Fragments to 0.08, but mainly smaller increasing in size downwards, hints of dips from 0 to 45 degrees. Dissolution breccia? Hard plug of cemented Breccia comprising grey and red-brown angular 38.20 0.20 mudstone clasts up to 0.04 with light brownish white angular weathered gypsum, up to 0.02, all in a matrix of clay and mudstone. Core loss/ very little recovery of sand and clay recovered as coarse- 38.50 0.30 grained gypsum sand in a matrix of brown clay – possibly all broken up by drilling? Breccia, angular clasts of light brownish white weathered gypsum and a 38.56 0.06 few red-brown mudstone/clay up to 0.015 in a brown clay matrix Breccia, angular clasts of mainly dark and medium grey clay (weathered 39.00 0.44 mudstone) plus a little gypsum in a matrix of brown and reddish-brown clay; clasts up to 0.04 all in a matrix of reddish-brown clay. Some sub- horizontal laminae of brown mudstone with silt/gypsum at base passing down into medium and dark grey mudstone. 0.05 of very hard breccia in root plug (?) of core barrel, possibly recemented by mixing during drilling or maybe just hard originally. Breccia, medium reddish brown, top 1.00 with abundant angular clasts 41.00 2.00 up to 0.08 - 0.10 of light-medium grey dolomitic limestone, thin and very thinly bedded, some muddy, looks like Brotherton Formation clasts. Plus,
9 abundant angular clasts of white-weathered gypsum, some clasts of dark grey and red-brown mudstone/clay in a matrix of smaller clay and mudstone clasts of similar lithologies, lower 1.00 with smaller clasts only up to 0.05 Breccia, grey clay matrix with medium gravel-sized clasts of grey, dark 41.14 0.14 grey and red-brown clay/weathered mudstone Muddy limestone, medium to dark grey, medium-grained crystalline with 41.50 0.36 abundant clay, good fizz with acid, some light grey gypsum nodules near base Calcareous mudstone medium grey with fine crystals of calcite, fairly 41.72 0.22 massive with a slight hint of banding Limestone, medium grey fine crystalline with a sucrous texture, some 41.79 0.07 calcite veining (fizz with acid) Mudstone, calcareous medium to dark grey with calcite grains up to fine- 42.43 0.64 grained, hints of bedding laminae with a dip of about 20 degrees becoming less cacitic mudstone in middle and passing down into calcareous mudstone near base (fizz with acid) Limestone, slightly brownish light grey with irregular laminae of dark 42.90 0.47 grey, dip about 45 degrees (sedimentary cross-bedding dip?); uneven contacts between uneven beds; good fizz with acid Limestone, light to medium grey, (fizz with acid), ranging from coarse 44.50 1.60 crystalline to light brownish grey very fine-grained/porcelaneous. Bedding occurs as colour banded laminae marking out thin beds becoming medium to thick-bedded downwards. Dip of laminae about 30 degrees at the top reducing to 20 degrees near the bottom. Bottom 1.00 massive with a few stylolitic contacts. Traces of a little ferruginous staining on a couple of joint surfaces, no signs of any dissolution or high water flow. Bottom of hole at 44.50
Detailed log of Bishop Monkton Borehole 2 NGR 432852, 465908
The upper part of this hole is described from drillers logs, the recovered core is described in detail.
Description of lithological unit Depth Thick- base ness (m) (m) Made up ground, sand and gravel (driller’s description) 11.00 11.00 Sand and gravel (driller’s description) 13.00 2.00 Clay, grey (driller’s description) 15.50 2.50 Limestone, grey, broken (driller’s description) 18.00 2.50 Limestone, cobbles (driller’s description) 19.00 1.00 Limestone, broken (driller’s description) 20.00 1.00 Limestone, soft (driller’s description). No recovery except for a few 21.50 1.50 cobble-sized pieces of re-drilled light grey dolostone and a little reddish- brown clay Limestone, grey clay (driller’s description) Only 0.42 of recovery out of 23.00 1.50 1.50, dolomitic silt, light yellowish brown, plus a few fragments of grey calcite. Sequence probably represents highly weathered dolostone or dolomitic limestone. Sand and fine gravel – possibly not in situ, or possibly washed in? 23.40 0.40 composed of angular and sub-rounded medium grey limestone and light yellowish brown dolostone with a few clear quartz grains; uncemented or poorly cemented with light yellowish-brown silt and clay becoming well cemented near base. However, this could be drilling material that has 10 caved and washed. It is similar to material in borehole 1 which was left when the casing was changed. No casing change is noted on the driller’s logs, but the casing is noted to stop at 18m depth. Alternatively, this could be material washed into a past cavity in the sequence. Dolostone, mainly light yellowish brown about 50/50% highly weathered 24.50 1.10 to dolomitic silt and 50% thin and very thin-bedded dolostone. A few reddish-brown mudstone/clay laminae and very thin beds, also partings of cacitic veins along some beds which dip at between 10 and 15 degrees No recovery drillers log says marl, red, but nothing in box 26.00 1.50 Only 0.50 recovery for 1.50 drilling. Sand and gravel comprising coarse 27.50 1.50 and fine gravel composed dominantly of sub-rounded Carboniferous limestone and some greyish brown fine-grained sandstone. The matrix is coarse sand which is clayey in places. This combination of clasts looks like it has been derived from the local glacial till. It is possible that this deposit is of material washed into an underground cavity. Given the depth of casing at 18m, which according to the drillers is within the limestone sequence the derivation of the sand and gravel as a fill material in a cavity is feasible. Dolostone, light brownish yellow, very fine-grained compact rock with 27.60 0.10 traces of the fossil Calcinema permiana on one bedding plane. This fossil looks like tiny match sticks and may be slightly carbonaceous or sites for crystal growth. c. 1.00 recovery over 1.40m Breccia of reddish-brown sandy clay and 29.00 1.40 clay matrix with about 20% clasts including one angular coarse-gravel sized clast of fine-grained red-brown sandstone (possibly Sherwood Sandstone) one yellow brown dolomitic clay and toward base angular weathered yellow brown dolostone fragments and coarse gravel-sized to boulder-sized clasts. c. 1.00 recovery over 1.50m. Silt with dolostone fragments light 30.50 1.50 yellowish brown, largely weathered to silt with angular unweathered fragments. Some laminae of red-brown and yellowish-brown clay and silt; more rock is present towards the base. All weathered Brotherton Formation. Very poor recovery of c. 0.30 over 1.50m. Dolostone, light yellowish 32.00 1.50 brown, very fine-grained to silty in angular fragments and some similarly coloured dolomitic silt. Weathered Brotherton Formation. Very poor recovery of c.0.50 over 1.50m. Dolostone, silt grade passing 33.50 1.50 down into fine-grained crystalline, light grey with porous crystalline light grey limestone that has a good fizz with acid. Some re-drilling of hard material. Weathered Brotherton Formation. Poor recovery, c. 0.70 over 1.50m. Dolomitic silt, light yellowish brown 35.00 1.50 with similarly coloured angular fragments of very fine-grained silty dolostone. Weathered Brotherton Formation. Dolostone, light yellowish brown, silty to very fine-grained, porcelaneous 35.20 0.20 fairly hard as two beds Sand, medium to coarse-grained quartz and grey limestone, plus 35.40 0.20 dolomitic silt – washed in material? Siltstone, and muddy siltstone, medium greyish brown, possibly a bit 35.50 0.10 dolomitic. c. 1.00 recovery over 1.35m. Mudstone, grey, laminated and very slightly 36.75 1.25 gypsiferous in a few places with bed-parallel lenticular laminae of gypsum. Passing down into medium grey and brownish grey clay with no gypsum remaining. Sharp base of dark grey laminated clay/mudstone with fine fibrous gypsum vein. Highly weathered Edlington Formation Mudstone, medium grey gypsiferous with stringers and veins of white 37.12 0.37 fibrous gypsum, two veins up to 0.03. Change to reddish brown below. Mudstone, reddish brown with a little grey, slightly gypsiferous with 38.60 1.48 disseminated gypsum and scattered cross-cutting very fine veins; 0.02 fibrous gypsum near base and 0.05 bed of muddy gypsum, medium reddish brown with well-developed platy crystals up to 5mm. Very thin
11 beds of gypsum and fibrous gypsum veins near base; veins 0-0.04 and 2x 0.02 in lower part Poor recovery c. 0.20 over 0.40. Clay, grey with angular grey mudstone 39.00 0.40 fragments Gypsum, medium grey and reddish-brown coarsely crystalline, muddy in 39.10 0.10 places with 0.03 fibrous gypsum at base Gypsum, light and medium grey, banded forming massive units of 0.16, 40.50 1.40 0.36, 0.20 and 0.17 thick separated by fibrous gypsum veins mainly bed- parallel, but one cross-cutting. The gypsum is massive and coarse- grained to alabastrine. A little red-brown gypsum and muddy gypsum is present near top and towards base. Poor recovery c. 0.60 over 1.20m. Breccia of light grey and light brownish 41.70 1.20 grey gypsum, very fine-grained and highly weathered in a matrix of red- brown clay that has dried out; one clast up to 0.06 of coarse-grained grey gypsum Gypsum, light grey banded medium grey in places and reddish brown 42.00 0.30 near top; bed-parallel fibrous gypsum veins to 0.01 thick; dip c. 40 degrees; 0.03 fibrous gypsum at base Gypsiferous mudstone, medium reddish brown and red-brown, 42.30 0.30 laminated with gypsum increasing towards base with coarse crystalline gypsum forming the basal bed; dip about 30 degrees Poor recovery, c. 0.90 over 1.50m. Breccia, red-brown clay with 43.00 0.70 fragments and clasts of weathered gypsum Clay, reddish brown with laminae of muddy gypsum all weathered, dip 43.90 0.90 sub-horizontal, but highly disrupted in places. At 43.50 a thin gypsiferous mudstone, red-brown at top and light grey below. Below that medium to dark red-brown clay with laminae of silt and probable residual gypsum grains after dissolution. Dip of laminae 30 degrees. Dissolution residue and breccia, clay, medium red-brown and medium 45.00 1.10 grey, irregularly laminated in places, chaotic in others with sporadic dark grey angular mudstone fragments and scattered gypsum grains; clasts are up to 0.05. Breccia, medium red-brown and dark grey with angular fragments of clay 46.30 1.30 and a little gypsum up to 0.03; traces of banding in some places, chaotic in others. Breccia, clay, medium dark brownish grey very soft and disturbed with 46.50 0.20 clasts up to 0.02 of red-brown clay Gypsiferous mudstone, medium grey, with coarse crystalline laminae 46.75 0.25 and disseminated gypsum; dip about 30 degrees. Mudstone, medium grey, slightly gypsiferous with stringers and some 47.50 0.75 nodules of gypsum up to 0.02; dip about 30 degrees. Breccia, composed of clay, reddish brown with a few traces of lamination. 48.80 1.30 About 10-15% of angular to sub-angular clasts of gypsum and gypsiferous mudstone, light grey to brownish grey in colour with medium and dark grey mudstone fragments. Clasts range in size from sand grade to a 0.10 clast of gypsum at base sitting abruptly on the limestone below; this basal core shows drilling marks and it may have a ground-down contact. Limestone, light grey, very fine grained, (fizz with acid), very thin to thin- 49.10 0.30 bedded with dark grey clay/mudstone partings with stylolitic contacts and a general dip of 10-15 degrees Limestone, light grey,(fizz with acid) fine grained at top with a few muddy 50.00 0.90 laminae, becoming massive and coarse-grained below 49.20; the limestone is medium to thin-bedded with a few very thin beds in the middle, bedding shown by weak stylolitic contacts; probable bivalve shell up to 0.04 at 49.75; dip about 5-10 degrees. Bottom of hole at 50.00 metres
12 Photographs of Bishop Monkton Borehole1
Figure 3 Bishop Monkton BH 1 19.00-23.00 Poor recovery of foundered Brotherton Formation dolostone
Figure 4. Bishop Monkton BH 1 23.00-28.00 Poor recovery of foundered weathered Brotherton Formation dolostone
13 Figure 5. Bishop Monkton BH 1 28.00-31.50 Foundered weathered Brotherton Formation dolostone on collapse breccia in clay (weathered mudstone)
14 Figure 6. Bishop Monkton BH 1 30.10 Foundered weathered Brotherton Formation dolostone (as light yellowish-brown clay) on collapse breccia in clay (weathered mudstone)
15 Figure 7. Bishop Monkton BH 1 30.30 collapse breccia of dolostone and clay (weathered mudstone) fragments in a clay matrix
16 Figure 8. Bishop Monkton BH 1 30.70 collapse breccia of clay (weathered mudstone) with a little dolostone in a clay matrix
17 Figure 9. Bishop Monkton BH 1 31.10 Collapsed mudstone with a little gypsum showing some in situ dissolution of gypsum
18 Figure 10. Bishop Monkton BH 1 31.40 Collapsed mudstone with a little gypsum showing some in situ dissolution of gypsum
19 Figure 11. Bishop Monkton BH 1 31.50-35.00 Collapsed mudstone with gypsum showing some partial in situ dissolution of gypsum
20 Figure 12. Bishop Monkton BH 1 32.29 Mudstone with relic gypsum crystals that look like coarse sand after the dissolution of gypsum, probably originally as fibrous veins.
21 Figure 13. Bishop Monkton BH 1 32.45 Mudstone with relic gypsum crystals that look like coarse sand after the dissolution of gypsum, probably originally as fibrous veins, also some relic gypsum veins and distorted clay after mudstone. 22 Figure 14. Bishop Monkton BH 1 32.85 Partially dissolved gypsum that is highly weathered to a light grey or light pinkish brown gypsum silt.
23 Figure 15.Bishop Monkton BH 1 33.50 Partially dissolved gypsum that is highly weathered to a light pinkish brown gypsum silt with a prominent bed in the lower part; red-brown laminated mudstone weathered to clay.
24 Figure 16. Bishop Monkton BH 1 34.25 limestone in red-brown clay that was formerly mudstone.
25 Figure 17. Bishop Monkton BH 1 34.65 Laminae of calcareous silt in red-brown clay after the weathering of calcareous siltstone and interbedded mudstone.
26 Figure 18. Bishop Monkton BH 1 33.50-39.00 Soft red-brown clay at top with poor recovery over collapse breccias with dissolution residues.
27 Figure 19. Bishop Monkton BH 1 37.60 Dissolution residue and collapse breccia composed of clay fragments and gypsum fragments in a clay matrix.
28 Figure 20. Bishop Monkton BH 1 37.90 Dissolution residue and collapse breccia composed of clay fragments and gypsum fragments in a clay matrix.
29 Figure 21. Bishop Monkton BH 1 38.80 Dissolution residue and collapse breccia composed of clay fragments and gypsum fragments in a clay matrix. Note coating of core with brown clay up to 0.01 thick plastered on during drilling
30 Figure 22. Bishop Monkton BH 1 39.00-41.50 Collapse breccia including limestone from the overlying Brotherton Formation and gypsum from the Edlington Formation resting on limestone of the Cadeby Formation.
31 Figure 23. Bishop Monkton BH 1 39.38 Collapse breccia including light grey limestone from the overlying Brotherton Formation and weathered white gypsum from the Edlington Formation
32 Figure 24. Bishop Monkton BH 1 39.55 Collapse breccia including light grey limestone from the overlying Brotherton Formation and weathered white and pink gypsum from the Edlington Formation
33 Figure 25. Bishop Monkton BH 1 40.90 Collapse breccia weathered white and pink gypsum with grey mudstone from the Edlington Formation
34 Figure 26. Bishop Monkton BH 1 41.20 Collapse breccia weathered white and reddish- brown gypsum with grey and red-brown clay from the Edlington Formation
35 Figure 27. Bishop Monkton BH 1, 41.45 Crystalline muddy limestone at the top of the Cadeby Formation and immediately below the collapse breccia.
36 Figure 28. Bishop Monkton BH 1 41.50-44.50 (bottom of hole) grey limestone over calcareous mudstone resting on massive limestone all belonging to the Cadeby Formation
37 Figure 29. Bishop Monkton BH 1 42.00 Calcareous mudstone of the Cadeby Formation
38 Figure 30. Bishop Monkton BH 1 42.90 Steeply dipping limestone (cross-bedding?) of the Cadeby Formation
39 Figure 31. Bishop Monkton BH 1 44.00 Massive banded crystalline limestone with a moderate dip to the lamination; Cadeby Formation
40 Figure 32. Bishop Monkton BH 1 44.30 Massive limestone with stylolitic contacts; Cadeby Formation
41 Photographs of Bishop Monkton Borehole 2
Figure 33. Bishop Monkton BH2, 18.00-28.50 very poor recovery of highly weathered Brotherton Formation dolostone. At 23.50 in the middle of the box sand is present possibly due to cleaning the borehole.
42 Figure 34. Bishop Monkton BH2, 23.50 sand due to cleaning the borehole.
43 Figure 35. Bishop Monkton BH2, 24.40 Brotherton Formation dolostone with calcitic mudstone laminae.
44 Figure 36. Bishop Monkton BH2, 26.00-30.50 Poor recovery of sand and gravel near top over collapse brecciated mudstone and dolostone resting on highly weathered dolostone. It is likely that this is all part of a collapsed or partly washed in sequence.
45 Figure 37. Bishop Monkton BH2, 26.00-27.00 Sand and gravel with red-brown clay. This could be washed in material deposited in a cavity, Alternatively, it could result from the drilling, but no problems were noted on the driller’s logs here. Washed in deposits are common in collapse breccias associated with sinkholes.
46 Figure 38. Bishop Monkton BH2, 29.00 A bedding surface in Brotherton Formation dolostone with poorly preserved faint rod-like markings and tube-like cavities that are typical of the fossil alga Calcinema permiana that occurs extensively in the Brotherton Formation.
47 Figure 39. Bishop Monkton BH2, 29.00 A close-up view of a bedding surface in with poorly preserved faint rod-like markings and tube-like cavities that are typical of the fossil alga Calcinema permiana that occurs extensively in the Brotherton Formation.
48 Figure 40. Bishop Monkton BH2, 30.00 Collapse breccia with fragments of weathered dolostone and one of fine-grained red-brown sandstone, possibly from the Sherwood Sandstone Group.
49 Figure 41. Bishop Monkton BH2, 30.50- 35.00 poor recovery of weathered and fragmented Brotherton Formation dolostone and limestone
Figure 42. Bishop Monkton BH2, 35.00- 38.00 Brotherton Formation dolostone on sand with dolomitic clay resting on weathered grey mudstone becoming red-brown downwards, gypsum increasing downwards, dissolved at top.
50 Figure 43. Bishop Monkton BH2, 35.15- 35.40 Brotherton Formation dolostone on sand; contact ground by drilling, sand may be original or introduced?
51 Figure 44. Bishop Monkton BH2, 38.00- 40.50 Gypsiferous red-brown mudstone with gypsum resting on massive grey gypsum passing down into reddish brown gypsum.
52 Figure 45. Bishop Monkton BH2, 40.00 massive gypsum and fibrous gypsum, dip about 30 degrees, but gypsum commonly has contorted strata and steep dips due to hydration from anhydrite, collapse also induces steep dips.
53 Figure 46. Bishop Monkton BH2, 40.50-45.00 gypsum on collapse breccia
54 Figure 47. Bishop Monkton BH2, c.41.00 breccia of weathered gypsum fragments in a clay matrix
55 Figure 48. Bishop Monkton BH2, 42.00 massive gypsum with fibrous gypsum at base. The fibrous gypsum shows a fairly common bipartite form with an incipient central mudstone parting.
56 Figure 49. Bishop Monkton BH2, 42.30 reddish grey gypsum and muddy gypsum with red-brown mudstone
57 Figure 50, Bishop Monkton BH2, c.43.00 Weathered red-brown mudstone reduced to clay with weathered gypsum beds
58 Figure 51. Bishop Monkton BH2, c.43.90 Clay with residual gypsum grains weathered from mudstone with gypsum
59 Figure 52. Bishop Monkton BH2, 44.80 Dissolution residue composed of clay with colour banding and a steep dip. Note this appears to be local material not collapsed material from above.
60 Figure 53. Bishop Monkton BH2, 45.00 Dissolution residue composed of clay with colour banding and a steep dip. Note it is local material not collapsed material from above.
61 Figure 54. Bishop Monkton BH2, 44.80 Dissolution residue composed of clay with gypsum fragments.
62 Figure 55. Bishop Monkton Borehole 2 45.00-47.50 Red-brown breccia on grey gypsiferous mudstone with grey mudstone at base
63 Figure 56. Bishop Monkton BH2, 46.20 Dissolution residue composed of clay with gypsum. Note the c. 0- 0.01 of brown clay on the margins of the core plastered on by the drilling process.
64 Figure 57. Bishop Monkton BH2, 46.15 Close up of dissolution residue composed of clay with gypsum. Note the up to 0.01 of brown clay on the margins of the core plastered on by the drilling process.
65 Figure 58. Bishop Monkton BH2, 46.17 Close up of dissolution residue composed of clay with gypsum. Note the 0 to 0.01 of brown clay on the margins of the core plastered on by the drilling process.
66 Figure 59. Bishop Monkton BH2, 46.50 What was very soft clay with clay fragments, now dried.
67 Figure 60. Bishop Monkton BH2, 46.90 Grey gypsiferous mudstone with a sub- horizontal dip.
68 Figure 61. Bishop Monkton BH2, 47.50-50.00. Red-brown dissolution residue and collapse breccia over grey limestone of the Cadeby Formation.
69 Figure 62. Bishop Monkton BH2, 49.50 Close up of broken surface of the coarse- grained crystalline limestone that forms the upper part of the Cadeby Formation.
70 Figure 63, Bishop Monkton BH2, 49.50 Coarse-grained crystalline limestone with stylolitic contacts that forms the upper part of the Cadeby Formation.
71 Figure 64. Bishop Monkton BH2, 49.75 Close up of possible bivalve in the limestone that forms the upper part of the Cadeby Formation.
72 Figure 65. Bishop Monkton BH2, 49.90 Close up of stylolitic bedding plane contact in the limestone that forms the upper part of the Cadeby Formation.
73 Discussion about the boreholes and local geology
The general sequence in the Ripon area in places without any gypsum dissolution is:
Formation Thickness (m) Roxby Formation mudstone with up to 10m of gypsum at base 20.00 Brotherton Formation dolomitic limestone and dolostone 12.00-14.00 Edlington Formation mudstone with up to 30-40m of gypsum at 40.00-50.00 base Cadeby Formation dolostone and limestone 50.00-60.00
The Ripon sequence is largely based on the Burtree Caravan Park Borehole No SE37SW/573 drilled to the east of Ripon at NGR 431770, 472673 with additional information from holes further east. While this hole is 7km north of Bishop Monkton, it does accord with information (for the Middle Marl, now Edlington Formation) from south and east of Bishop Monkton as summarised in Cooper and Burgess (1993) figure 15.
Figure 66. The generalised vertical sequence of the Zechstein Group, Permian rocks in the Ripon and Bishop Monkton area
From Darlington in the north, through Ripon and Bishop Monkton to Doncaster in the south the Permian rocks have a similar disposition with a gentle easterly dip. Down dip at depth the full gypsum sequence is present as shown in the vertical section (Figure 65). Towards the outcrop of the Roxby and Edlington formations the gypsum progressively dissolves in a piecemeal manner controlled by the rock jointing and the presence of valleys that intersect the hydrogeological water flow from the high
74 ground to the west (and also from the east in some places) down to the river valley system (Cooper 1986; Cooper 1998; Cooper 2008; Farrant and Cooper 2008; Cooper, Odling et al. 2013; Cooper 2020). Towards the outcrop of the Edlington Formation the gypsum becomes more dissolved and at outcrop usually only the insoluble mudstone parts of the formation remain.
Figure 67. Cross-section through the Ripon area showing the water flow through the gypsum sequences to the valley of the River Ure. The situation at Bishop Monkton is similar to that west of Ripon; diagram from Cooper, Odling et al 2013.
Down dip from the outcrop the sequence can include very complex areas of collapsed and partially collapsed ground. The nature of the dissolution and collapse by forming sinkholes and breccia pipes means that the geology can change from apparently solid rock to disaggregated strata in a metre or so as shown in Figure 67. It is important to note that due to collapse steep dips and mixed brecciated strata can occur suggesting greater thicknesses for the Brotherton Formation than seen in unaffected gently dipping strata.
Figure 68. Cross section through part of Ripon with the Brotherton Formation at rockhead showing the rapid changes in geology. At Bishop Monkton there is much less gypsum than this remaining, but there may be similar relic features.
75 The Bishop Monkton sequence is proved by the two new boreholes summarised from the detailed logs in the two tables below and from a borehole at High Barn.
Bishop Monkton Borehole 1 Formation/unit and comments Depth Thickness (m) present (m) Superficial deposits, driller’s descriptions boulder clay on 15.00 15.00 sand and gravel Highly weathered and probably brecciated dolostone and 29.00 14.00 limestone of the Brotherton Formation Collapse breccia of foundered mudstone with gypsum of 41.14 12.14 the Edlington Formation mainly highly weathered and reduced to clay except between 33.00 and 35.00 where the rock is more intact, but may represent a large collapsed block that has not brecciated. Limestone of the Cadeby Formation, atypically this is 44.50 3.36 proved limestone whereas most of the Cadeby Formation is dolostone. To bottom of hole at 44.50
Bishop Monkton Borehole 2 Formation/unit and comments Depth Thickness (m) present (m) Superficial deposits, driller’s descriptions, made ground, 15.50 15.50 sand and gravel on grey clay Dolostone and limestone with units composed of disparate 35.20 19.70 materials including sand and gravel and clay with clay clasts and sandstone. The unit is mainly Brotherton Formation, but has poor recovery and units within it that appear to be collapse material A mixture of brecciated clay (formerly mudstone) with 48.80 13.60 gypsum and more intact sequences of mudstone and gypsum interspersed with breccia units indicative of partial dissolution of the Edlington Formation sequence Limestone of the Cadeby Formation, atypically this is 50.00 1.20 proved limestone whereas most of the Cadeby Formation is dolostone. To bottom of hole at 50.00
Both of the holes show a similar thickness of superficial deposits and both show the same general sequence, though the amounts of dissolution and collapse are different in each.
Situated about 1km north-east of the site the BGS records have a log for High Barn, Bishop Monkton record SE36NW/77 [NGR 433300, 466770]. This hole gives a local section for the likely thicknesses of the formations a little down dip from the Bishop Monkton site.
76 High Barn Borehole, Bishop Monkton NGR 433300, 466770 Formation/unit and comments Depth (m) Thickness present (m) Superficial deposits 9.70 9.70 Roxby Formation mudstone 24.90 15.20 Dolomitic limestone – Brotherton Formation 42.00 17.10 Mudstone with gypsum – Edlington Formation 59.00 17.00 Gypsum – Edlington Formation 68.00 9.00 Mudstone, red-brown – Edlington Formation 68.90 0.90 Dolomitic limestone with artesian water – Cadeby 70.00 1.10 Formation to bottom at 70.00 proved
The High Barn borehole shows the thickness of the Brotherton Formation to be locally around 17.00 metres, which is thicker than that suggested by (Cooper and Burgess 1993) who calculated about 12m for this area. This hole also indicates gypsum dissolution and as noted above the Brotherton Fm may be tilted or foundered increasing the thickness. The likely thickness for the Brotherton Formation at Bishop Monkton is thus thought to be unlikely to exceed 17.00.
In the Bishop Monkton 1 borehole 14.00 of Brotherton Formation is proved beneath the superficial deposits and the top part may be eroded; 14.00 is thus a minimum thickness, but the rock may be brecciated and thickened.
In the Bishop Monkton 2 borehole total thickness of the Brotherton Formation is 19.70, like borehole 1 the top may be eroded at the base of the superficial deposits so this is a minimum thickness. The unit in borehole 2 includes about 3.30 of other deposits including sand and gravel and breccia that may relate to collapse and would not normally be expected in the formation. It is thus suggested that the poor recovery, weathering, large thickness and unusual deposits all point to the Brotherton Formation in borehole 2 as being considerably foundered and broken up, possibly like the sinkhole between A and B in Figure 67above.
In Bishop Monkton Borehole 1 there is very little gypsum remaining and the interval occupied by the Edlington Formation comprises mainly breccia and collapsed material with a thickness of just 12.14m. In Bishop Monkton Borehole 2 the equivalent strata are slightly thicker at 13.60m and approximately 1.80m of gypsum remains in the sequence. Somewhere in the region of 30-40m of gypsum has dissolved in the local area severely affecting the overlying Brotherton Formation. The timing of the majority of this dissolution is unclear, but probably relates to the last and maybe earlier ice ages. However, the current water flow is likely to be continuing to dissolve the remaining gypsum resulting in subsidence and collapse. This is suggested by the development of a pond lying to the south-east of the site and changes in the shape of a pond north of the site. It is also indicated by subsidence in the Bishop Monkton area recorded by Cooper (1986). The cross-sections presented above from Cooper (1998) show how the geology can change within a metre of so between that in a collapse and that outside the collapse margin. Because of this there may be more significant gypsum adjacent to areas where it has dissolved.
Along most of the outcrop the mechanism for dissolution is artesian water flow through the dolostones of the Cadeby Formation up into the overlying gypsum of the Edlington Formation and out into the local river system that is commonly deeply incised with buried valleys (Cooper 1998; Cooper, Odling et al. 2013). The Cadeby Formation is usually dolostone, but in some places, such as these two holes in Bishop Monkton it exists as limestone. 77
Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
APPENDIX D GEOINVESTIGATE S BO‘EHOLE LOGS CP/‘C & CP/‘C
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GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 1 Sheet No. 1 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Samples / Tests Depth to Depth (m) -ness (m) No Type Depth (m) Results Water (m) MADE GROUND: Brown clayey, sandy topsoil D 0.20m 1050 B 0.20-1.00m 1.05 1.00 Firm sandy gravelly CLAY with frequent cobbles noted Gravel is fine to coarse of sandstone and U 1.20-1.65m 34 Blow s/95% limestone D 1.70m >Very sandy between 1.70m - 3.60m 2.00 S 2.00-2.45m N=4
B 2.00-2.50m
3.00 S 3.00-3.45m N=10
B 3.00-3.50m
4.00 U 4.00-4.45m 51 Blow s/80% 6350
D 4.50m
5.00 S 5.00-5.45m N=27
B 5.00-5.50m
6.00
U 6.50-6.95m 72 Blow s/40%
D 7.00m 7.00
7.40 Firm to stiff brown mottled grey silghtly sandy laminated silty CLAY S 8.00-8.45m N=26 8.00
B 8.00-8.50m
2500 9.00
U 9.50-9.95m 82 blow s/NR
9.90 10.00 Remarks: Light cable percussion drilling to 12.50m Key: B Bulk disturbed sample Cv Shear vane Chiselled for 11.70 to 12.30 for 45mins S Standard Penetration Test W Water sample Water strike at 9.80m rising to 6.90m in 20mins C SPT with solid cone D Small disturbed sample BH 1 U Undisturbed sample www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 1 Sheet No. 2 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Samples / Tests Depth (m) -ness (m)Type Depth (m) Results (m) Dense to very dense sandy fine to coarse GRAVEL of sandstone and limestone S 10.00-10.45m N=47
B 10.00-10.50m 11.00
D 11.50m 2500
>Cable Percussive Borehole Termnated a S 12.00-12.45m N = 50+ 12.00 Rotary Rig follow-on Using 6" casing.
13.10 Stiff brown to grey to reddish brown sandy, 13.00 gravelly CLAY (drillers description)
1900 14.00
>Coring Started using PQ Wireline System Coring Information 15.00 Depth Total Core Solid Core 15.00 No recovery - Assumed to be DOLOSTONE 15.00m of the Brotherton Formation No Recovery
16.00m 16.00 16.00m
No Recovery
17.00m 17.00 4000 17.00m
No Recovery
18.00m 18.00 18.00m
No Recovery
19.00 19.00m 19.00 Limited recovery extremely weak light brown 19.00m highly weathered LIMESTONE of the Brotherton Formation. Box 1 24% 0%
20.50m 20.00 Remarks: Rotary Coreless Device 12.50m - 15.00m using 6" Key: Box - Core Box Rotary Coring Below 15.00m using PQ Wireline 15/09/2020 - Drilling 0.00m to 15.00m 16/09/2020 - Drilling 15.00m to 19.00m BH 1 17/09/2020 - Drilling 19.00m to 28.00m www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 1 Sheet No. 3 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Coring Information Depth (m) -ness (m)Depth Total Core Solid Core (m) Limited recovery extremely weak light brown highly weathered LIMESTONE of the Brotherton Formation. 20.50m 20.50m 21.00
Box 1 34% 5%
4500 22.00m 22.00 22.00m
> Driller recorded lose of water flush at 22.50m Box 1 30% 3% 23.00
23.50 23.50m No recovery - Assumed to be LIMESTONE 23.50m of the Brotherton Formation 24.00 > Driller has recorded weak/broken ground 1500 No Recovery between 23.50m and 25.00m
25.00 25.00m 25.00 Extremely weak light brown completely 25.00m weathered LIMESTONE (Recovered as very stiff clay) of the Brotherton Formation. Box 2 50% 0% 26.00
26.50m 26.50m
27.00 4000 Box 2 75% 15%
28.00m 28.00 28.00m
Box 3 50% 20%
29.00 29.00m 29.00 No recovery - Assumed to be LIMESTONE 29.00m of the Brotherton Formation 1000 No Recovery > Driller has recorded weak/broken ground between 29.00m and 30.00m 30.00m 30.00 Remarks: Key: Box - Core Box 17/09/2020 - Drilling 19.00m to 28.00m 18/09/2020 - Day Works 21/09/2020 - Drilling 28.00m to 35.50m BH 1 www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 1 Sheet No. 4 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Coring Information Depth (m) -ness (m)Depth Total Core Solid Core (m) Extremely weak highly weathered 30.00m MUDSTONE (recovered as stiff clay) of the Edlington Formation. Box 3 100% 100% 31.00
> gypsum crystals within sand element of 31.50m mudstone at 32.29m to 32.45m 31.50m
32.00 > Partially dissolved gypsum within silt Box 4 100% 100% element of mudstone at 32.85m
33.00m 33.00 33.00m
Box 4 100% 100%
34.00m 34.00 34.00m Box 4 100% 100% 9000 > Light pinkish brown gypsum silt noted 35.00m within mudstone laminations at 33.50m 35.00m 35.00 Box 5 100% 100%
35.50m 35.50m
100% 100% 36.00 Box 5
36.50m 36.50m
> gypsum crystals within sand element of 37.00 mudstone at 37.60m and 37.90m 100% 100% Box 5
38.00m 38.00m 38.00
90% 90% Box 5
39.00 39.00m Weak highly weathered MUDSTONE 39.00m 39.00 (recovered as stiff gravelly clay) of the Edlington Formation. 2100 Box 6 100% 70% >Gravel element contains limestone from the overlying brotherton formation and gypsum crystals. 40.00m 40.00 Remarks: Key: Box - Core Box 21/09/2020 - Drilling 28.00m to 35.50m 22/09/2020 - Drilling 35.50m to 43.00m BH 1 www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 1 Sheet No. 5 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Coring Information Depth (m) -ness (m)Depth Total Core Solid Core (m) Very weak highly weathered MUDSTONE 40.00m (recovered as stiff gravelly clay) of the Edlington Formation. 2100 > gravel contains gypsum crystals. Box 6 100% 75% 41.10 41.00 Very weak completely weathered grey highly weathered LIMESTONE of the 41.50m Cadeby Formation 41.50m 1300 42.00 Box 7 100% 20%
42.40 Medium strong slightly weathered 43.00m LIMESTONE of the Cadeby Formation 43.00m 43.00
3100 Box 7 100% 100%
44.00
44.50 44.50m Borehole Complete at 44.50m
45.00
Remarks: Key: Box - Core Box 22/09/2020 - Drilling 35.50m to 43.00m 23/09/2020 - Move to BH2 and grout hole. BH 1 www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 2 Sheet No. 1 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 11th to 29th September 2020
Depth Description of Strata Thick Level Legend Samples / Tests Depth toDepth (m) -ness (m) No Type Depth (m) Results Water (m) MADE GROUND: Brown clayey, sandy topsoil 400 D 0.20m 0.40 Firm sandy gravelly CLAY with frequent cobbles B 0.20-1.00m noted. Gravel is fine to coarse of sandstone and 1.00 limestone S 1.20-1.65m N=18
D 1.70m 2.00 U 2.00-2.45m60blow s/100%
B 2.00-2.50m
3.00 S 3.00-3.45m N=31
B 3.00-3.50m
4.00 U 4.00-4.45m 90 Blow s/66%
D 4.50m
5.00 S 5.00-5.45m N=25 10700 B 5.00-5.50m
6.00
U 6.50-6.95m80 Blow s/100%
D 7.00m 7.00
S 8.00-8.45m N=26 8.00
B 8.00-8.50m
9.00
U 9.50-9.95m 75 blow s/70%
10.00 Remarks: Light cable percussion drilling to 14.75m Key: B Bulk disturbed sample Cv Shear vane Chiselled for 14.10 to 14.50 for 30mins S Standard Penetration Test W Water sample Water strike at 12.30m rising to 7.90m in 20mins C SPT with solid cone D Small disturbed sample BH 2 U Undisturbed sample www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 2 Sheet No. 2 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata Thick Level Legend Samples / Tests Depth (m) -ness (m)Type Depth (m) Results (m) Firm sandy gravelly CLAY with frequent cobble noted Gravel is fine to coarse of sandstone and limestone. 10700
11.10 S 11.00-11.45m N = 21 11.00 Stiff brown mottled grey sandy laminated silty CLAY. B 11.00-11.50m 1500 12.00
12.60 Dense light brown sandy fine to coarse GRAVEL of sandstone and limestone S 13.00-13.45m N = 38 13.00 1400
B 13.00-13.45m 14.00 14.00 Very stiff brown to grey to reddish brown sandy, gravelly CLAY (drillers description) S 14.30-14.75m N = +50
>Cable Percussive Borehole Termnated 1500 and Rotary Rig follow-on with 6" casing 15.00
15.50 No recovery - Assumed to be LIMESTONE of the Brotherton Formation 16.00
17.00
>Coring using PQ Wireline System Coring Information 6000 Depth Total Core Solid Core 18.00 18.00m
> Driller has recorded weak/broken groun Box 1 No Recovery between 18.00m and 20.00m 19.00m 19.00 19.00m
Box 1 No Recovery
20.00m 20.00 Remarks: Rotary Coreless Device 14.75m - 18.00m using 6" Key: Box - Core Box Rotary Coring Below 18.00m using PQ Wireline 23/09/2020 - Drilling 0.00m to 11.00m 24/09/2020 - Drilling 11.00m to 24.50m BH 2 www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 2 Sheet No. 3 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Coring Information Depth (m) -ness (m)Depth Total Core Solid Core (m) No recovery - Assumed to be LIMESTONE 20.00m of the Brotherton Formation
6000 No Recovery 21.00
21.50 21.50m Extremely weak light brown completely 21.50m weathered LIMESTONE (Recovered as very stiff clay) of the Brotherton Formation. 22.00 Box 1 35% 35% 2000
23.00m >Non intact 23.00m to 23.50m 23.00m 23.00
23.50 Extremely weak to weak light brown 100% 30% completely weathered LIMESTONE of the Box 1 Brotherton Formation. 24.00
24.50m 24.50m 2500
25.00 No Recovery
26.00 26.00m Extremely weak to weak light brown 26.00m 26.00 completely weathered MUDSTONE (recovered as stiff clay) Box 2 50% 0%
27.00 2700
27.50m 27.50m
28.00 28.70 Box 2 75% 60% Extremely weak to weak light brown completely weathered LIMESTONE of the Brotherton Formation. 29.00m 29.00m 29.00 7050 Box 2 75% 60%
30.5 30.00 Remarks: Key: Box - Core Box 25/09/2020 - Drilling 24.50m to 35.00m
BH 2
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GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 2 Sheet No. 4 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Coring Information Depth (m) -ness (m)Depth Total Core Solid Core (m) Extremely weak to weak light brown completely weathered LIMESTONE of the Brotherton Formation. 30.50m
31.00 Box 3 10% 0%
32.00m 32.00m 32.00
7050 Box 3 20% 2%
33.00
33.50m 33.50m
34.00 Box 3 60% 0%
>Moderately strong below 35.00m 35.00m 35.75 35.00m 35.00 Extremely weak highly weathered grey MUDSTONE of the Edlington Formation. Box 4 100% 50%
36.00m 36.00m 36.00 550
>Gypsum vein noted, 4mm Box 4 90% 80%
37.00m 37.20 37.00m 37.00 Extremely weak highly weathered brown MUDSTONE of the Edlington Formation. Box 4 100% 50%
>Two gypsum vein noted, 3mm. 38.00m 38.00m 38.00 2200
Box 5 70% 40% 39.00 39.00 Moderately strong weathered light grey GYPSUM 39.50m 1500
40.00 Remarks: Key: Box - Core Box 28/09/2020 - Drilling 35.00m to 47.50m 28/09/2020 - 1.5 hours filling water bowser BH 2
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GEOINVESTIGATE Ltd Your Ref. G20280 Our Ref. BH No. 2 Sheet No. 5 of 5 Location: Church Farm, Bishop Monkton HG3 3RA DATE: 18th to 23rd September 2020
Depth Description of Strata ThickLevel Legend Coring Information Depth (m) -ness (m)Depth Total Core Solid Core (m) Moderately strong weathered light grey GYPSUM 1500 40.50 40.50m Very weak highly weathered MUDSTONE (recovered as stiff gravelly clay) of the 41.00 1200 Edlington Formation. Box 6 75% 20% 41.70 > Gravel of gypsum 40.30m Moderately strong weathered light grey 300 42.00 GYPSUM 42.00m Very weak highly weathered MUDSTONE 42.00m 42.00 (recovered as stiff gravelly clay) of the Edlington Formation. Box 6 75% 25%
> Light pinkish brown gypsum silt noted 43.00 within mudstone laminations at 43.50m to 43.90m. 43.50m 43.50m
44.00 Box 6 75% 25%
45.00m > gravel of gypsum noted 45.70m. 45.00m 45.00
6900
Box 7 100% 90%
46.00 > mudstone is grey between 46.50m and 47.50m 46.50m 46.50m
Box 7 100% 90% 47.00 > gypsum crystals noted within the mudstone at 46.15m. 47.50m 47.50m
48.00 Box 8 100% 100%
48.90m 49.00m Medium strong slightly weathered 49.00m 49.00 LIMESTONE of the Cadeby Formation 1100 Box 8 100% 100%
Borehole Complete at 44.50m 50.00m 50.00 Remarks: Key: Box - Core Box 29/09/2020 - Drilling 47.50m to 50.00m 29/09/2020 - Grout borehole. BH 2 www.geoinvestigate.co.uk April 2021 Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
APPENDIX E POND IMAGES
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APPENDIX F HISTORICAL MAPS.
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APPENDIX G POND INFILL
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APPENDIX H LIDAR IMAGING
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APPENDIX I BUTTRESSED BUILDING
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APPENDIX J REVEREND TUTE S 8 SINKHOLE ACCOUNT AT BISHOP MONKTON
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APPENDIX K GEOINVESTIGATES CORE PHOTOGRAPHS UNCUT AND CUT
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Photograph 1: Showing Box 1 and core recovered from BH1 between 19.00m and 23.50m.
Photograph 2: Showing Box 2 and core recovered from BH1 between 25.00m and 28.00m.
Photograph 3: Showing Box 3 and core recovered from BH1 between 28.00m and 31.50m.
Photograph 4: Showing Box 4 and core recovered from BH1 between 31.50m and 35.00m.
Photograph 5: Showing Box 5 and core recovered from BH1 between 35.50m and 39.00m.
Photograph 6: Showing Box 6 and core recovered from BH1 between 39.00m and 41.50m.
Photograph 7: Showing Box 7 and core recovered from BH1 between 41.50m and 44.50m.
BH2
Photograph 8: Showing Box 1 and core recovered from BH2 between 19.00m and 24.50m.
BH2
Photograph 9: Showing Box 2 and core recovered from BH2 between 26.00m and 30.50m. BH2
Photograph 10: Showing Box 3 and core recovered from BH2 between 30.50m and 35.00m.
BH2
Photograph 11: Showing Box 4 and core recovered from BH2 between 35.00m and 38.00m.
BH2
Photograph 12: Showing Box 5 and core recovered from BH2 between 38.00m and 40.50m.
BH2
Photograph 13: Showing Box 6 and core recovered from BH2 between 40.50m and 45.00m.
BH2
Photograph 14: Showing Box 7 and core recovered from BH2 between 45.00m and 47.50m.
BH2
Photograph 15: Showing Box 8 and core recovered from BH2 between 47.50m and 50.00m.
Ground Stability Assessment: Proposed Development - Church Farm, Bishop Monkton HG3 3RA G20280
APPENDIX L RECENT SINKHOLE ACTIVITY IN RIPON TOWN
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