WCM: WOODHOUSE COLLIERY PROPOSAL RADIOLOGICAL IMPLICATIONS of POTENTIAL SEABED SUBSIDENCE,SEISMICITY

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WEST CUMBRIA MINING: WOODHOUSE COLLIERY PROPOSAL RADIOLOGICAL IMPLICATIONS of POTENTIAL SEABED SUBSIDENCE SEISMICITY & “FAULT RE-ACTIVATION” beneath The CUMBRIAN MUD PATCH: INDUCED BY “MASS REMOVAL”, RAPID EXTRACTION & VOID SPACE CREATION

Briefing Paper For “Keep Cumbrian Coal in the Hole” (a Radiation Free Lakeland Campaign) Tim Deere-Jones Marine Radioactivity Research & Consultancy June 2020

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CONTENTS INDEX Intro & Major Conclusion ................................................................................................. ...... page 3 1: WCM’s proposed excavation and extraction methods ............................................... page 7 2: Summary of mining subsidence and fault re-activation issues ................................... page 9 3: BGS comments on Cumbrian coalfield seismicity ....................................................... page 11 4: Possible outcomes of seismicity/subsidence in WCM’s subsea mining zone ............ page 12 5: Seismicity induced liquefaction .................................................................................. page 13 6: Distortion of seabed morphology ............................................................................... page 15 7: Cumbria County Council seabed subsidence monitoring ........................................... page 16 8: Application of seabed subsidence monitoring technology ........................................ page 17 9: “Backfilling” : WCM’s proposed mitigation ................................................................. page19 10: Fate and Behaviour of marine radioactivity ............................................................... page 20 11: Radioactivity in the Cumbrian Mud Patch ................................................................. page 22 12: Sellafield/Cumbrian Mud Patch and quantification of radioactivity ......................... page 23 13:

Official nuclear industry understanding of mechanisms of exposure and

` dose delivery .................................................................................................... ...... page 27 14: Independent empirical evidence of mechanisms of exposure and dose delivery..... page 29 15: Final Conclusions ................................................................................................ ........ page 31

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Introduction: This Briefing offers a review of the possible seabed morphological changes and marine pollution implications of the sub-sea coal mining venture proposed by West Cumbria Mining (WCM) at their Woodhouse Colliery site near St Bees Head.

WCM have designated and identified a sub-sea mining zone of the Irish Sea lying to the west of St Bees Head and extending at least 8kms offshore and southwards to within about 8km of the Sellafield site.

The WCM extraction proposals, using continuous mining methods, predict the extraction of approximately 3 million tonnes of coal per year over a 50 year period. This extraction rate will eventually generate a huge subterranean void space of approximately 136 million cubic metres (a volume greater than that of Wastwater Lake).

This briefing considers the impact of the creation of such a sub-sea void space on the possibility of sea bed subsidence in the area of the WCM designated sub-sea mining zone, and the subsequent potential for marine radiological pollution as a result of the subsidence induced re-suspension of the heavily radioactively contaminated sea bed sediments of the Cumbrian Mud Patch and surrounding sea bed areas. ………………………………………………………………………………………………………………………………………………….

Major Conclusions It is noted that there is a lack of data about the status of the existing historical galleries and workings of the West Cumbrian Coalfield. It is noted that there is a lack of accurate data about the history and status of any subsidence seismicity in the coalfield. It is noted that the BGS have concluded that the coalfield is heavily faulted and has a long history of subsidence and that it appears that there are no plans to monitor for any subsidence prior to, during the operational phase or in the post operational phase of the Woodhouse Colliery. It is noted that sub-sea monitoring equipment is available and could be deployed in the region in order to monitor for any subsidence effects arising as a result of the proposed Woodhouse Colliery “mass removal” extraction.

It is concluded that there is a real potential for subsidence to occur as a result of the “mass removal” and the creation of extensive sub-sea void spaces, and it is noted that such subsidence could generate earthquake and liquefaction effects which may extend onshore as far as the Sellafield/Moorside sites.

It is concluded that any seabed subsidence in the WCM designated sub-sea mining zone would generate re-suspension of Cumbrian Mud Patch heavily radioactive seabed sediments. It is noted that such an event would generate elevated doses of man-made radioactivity to coastal zone populations and sea users along both the Cumbrian coast and at “downstream” regions further afield.

Given the potential for such a radiological effect and the delivery of increased doses of radioactivity to relevant coastal zone communities, some of which have already been identified by the authorities as Coastal Critical Groups, the Woodhouse Colliery proposal (especially in the absence of any precautionary mandatory subsidence monitoring) is strongly contra-indicated and should be abandoned

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Summary of Conclusions Chapters 1,2 & 3: WCM have proposed a high intensity and high extraction rate over a 50 year programme of coal mining from a designated sub-sea mining zone. This sub-sea mining zone is known to have been poorly recorded in the past, and accurate and reliable surveying and charting of the existing historical galleries and workings appears to be incomplete.

However, from both the available historical records and more recent empirical evidence it is clear that the entire West Cumbrian Coalfield is relatively heavily faulted and that the coalfield has a long history of subsidence and related seismicity.

The WCM designated sub-sea mining zone, the related onshore zone and the intermediate field zones around it, are all reported by the BGS to have experienced a number of seismic events over a relatively long period as a result of ”severe geological problems” and “particularly, faulting”.

Chapters 4 & 5: The Briefing notes that, in the context of the proposed high annual extraction rate (3 million tons pa) over an extended time period (50 years), the “mass removal” at relative speed when coupled with the known geological problems and faulting issues may increase the risk of “induced fault-reactivation” seismicity in the WCM sub-sea mining zone.

It is noted that should this occur, there is good empirical evidence that such seismicity could induce “downward displacement” and seabed “liquefaction” events and a potential for seismic events affecting local terrestrial environments with “liquefaction” prone geology.

The Briefing references an historical earthquake at Barrow in Furness where reports strongly suggest that “liquefaction” occurred and also references a very recent and detailed geological survey of the Sellafield area which indicates an elevated potential for liquefaction at the Sellafield/proposed Moorside NPS site.

Chapter 6: The Briefing notes the scarcity of academic and scientific empirical study of seabed subsidence and morphological distortion due to mineral resource extraction processes. However, in the context of issues discussed in Chapter 2, it provides a discussion of possible “bad case” scenarios to set against WCM’s positive case scenarios.

The Briefing concludes that any subsidence within the WCM designated seabed mining zone will generate some form and degree of seabed morphological distortion. It is equally evident that any such seabed distortion will remobilise previously sequestered seabed sediments, and their associated pollutants, which will subsequently be transported and re-distributed through the regional marine and coastal environments. It is inevitable that such re-mobilisation and re-distribution will expose marine wildlife and human coastal populations and stakeholders to some degree of exposure doses to those pollutants via a number of mechanisms and pathways.

Chapter 7: It is noted that neither Cumbria County Council, the Coal Mining Authority, or the Mineral Planning Authority appear to have undertaken any historical monitoring of seabed subsidence in or around the sub-sea sectors of the West Cumbrian Coalfield. It is noted that Cumbria County Council’s (CCC) current subsidence monitoring plans only refer to onshore subsidence and onshore subsidence monitoring and that CCC has not

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proposed any form of seabed subsidence monitoring plan to be in place during either the operational, or the post operational phase of the WCM project.

It is concluded that this is contra-indicated by both the potential likelihood of seabed subsidence in the context of the rapid “mass removal” and the risk of the re-mobilisation of radio-logically contaminated seabed sediments in the event of any subsidence or seismicity.

Chapter 8: The Briefing reports that elsewhere in Europe, where applications are submitted for sub-sea hydrocarbon extraction seabed subsidence monitoring is mandated by the relevant authorities. The case of Italian offshore hydrocarbon extraction, where seabed subsidence monitoring technology has been deployed for some years, is referenced. In this example it is reported that such equipment is both reliable and remarkably accurate and capable of detecting seabed morphological distortions down to the 1cm per year scale.

The Briefing reports that the application of such technology to the sub-sea area above the WCM designated sub-sea mining zone is both feasible and imperative in order to gain pre-extraction baseline data from the designated zone and then operational phase and long term post operational phase data in order to both observe and respond to any subsidence or seismicity arising as a result of WCMs activity.

The Briefing recommends that any permission to WCM (from Cumbria County Council and other authorities) should be accompanied by a mandatory insistence that seabed subsidence monitoring technology be deployed as advised in the preceding paragraph.

Chapter 9: It is evident that WCM intend no remedial action backfilling in their designated sub-sea mining zone and that backfilling will be strictly limited to the mining zones underneath the MCZ. The implication of this commentary is that even WCM accept that some subsidence may occur and that backfilling as a remedial measure beneath the MCZ and onshore may be necessary. It is further evident that WCM’s estimation of the 150,000 ton volume of “reject” material which will be available for use in backfill mitigation would clearly be insufficient to backfill the approximately 136 million cubic metre void space to be created by the proposed extraction of the coal It is clear from academic studies and reports that “backfilling” using methods such as those proposed by WCM, at their designated mining area beneath the MCZ, are both outdated and less than perfect, and contain a number of inherent weaknesses which have generated negative commentary from contemporary observers and researchers who have warned of the need for “further research” and increased experimental study on the mechanical properties of backfill technology.

Chapters 10, 11 & 12: It is evident that there are no reliable calculations of the aggregated volume, or specific concentrations, of radio nuclides in any of the regional seabed environments or marine water columns.

However, It is equally clear that a consensus exists that large volumes of both soluble and sediment associated radio nuclides are sequestered in the regional seabed, including the sectors of the Cumbrian Mud Patch in the area of the WCM designated sub-sea mining zone. Monitoring of regional environmental samples chosen by the nuclear industry and government nuclear regulators makes it clear that mechanisms and pathways of biological re-concentration and bio-accumulation are present in the marine environment.

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The figures given by a 2002 DEFRA assessment of man-made radioactivity, for the sector of the Cumbrian Mud Patch adjacent to the WCM designated sub-sea mining zone, postulates that for 1 Am and 3 Pu nuclides there may be 37 TBq and for Cs 137 there may be 47 Tbq: ie a total of around 84,000,000,000,000 Bqs. The Briefing notes that this figure is representative of the assumed aggregated radioactivity for only 5 of the estimated 60 + nuclides known to be discharged from the Sellafield site and other regional licensed nuclear sites.

Chapters 13 &14: The empirical evidence collected by independent academics medical and citizen campaign researchers clearly demonstrates that neither the international nuclear industry, nor UK Government regulatory agencies and environmental protection agencies, have an adequate understanding of the full range of the mechanisms by which anthropogenic marine radioactivity transfer from marine environments to terrestrial environments and therefore delivers doses of sea discharged radioactivity to terrestrial coastal zone individuals and communities.

However the empirical evidence, provided by such independent research, clearly shows that marine radioactivity ad-sorbed to sedimentary particles suspended in the marine water column and dissolved in the marine water column, can transfer from the sea to the land by a number of mechanisms. This radioactivity can deliver dietary doses of marine radioactivity (via contaminated terrestrial foodstuffs) which may be higher than those received by some Groups eating seafood. In addition, the fact that such airborne sea-toland transfered radioactivity is shown to travel at least ten miles inland means that some of that airborne radioactivity will be inhaled by coastal zone communities, thus delivering an inhalation dose of marine radioactivity to terrestrial populations.

Clearly, if the radioactive sediments of the Cumbrian Mud Patch should be disturbed and re-suspended following induced subsidence/seismicity caused by the WCM “mass removal”, the re-mobilisation of those radioactive sediments would increase doses from accepted pathways (seafood, contact with marine environmental media, ingesting beach sand etc) in addition to the very significant pathways derived from the sea to land transfer mechanisms ignored and avoided by the nuclear industry and its supporters.

These multiple source doses, delivered as they are and would be over the longer term, are highly likely to have long term health implications on not only Cumbrian coastal communities but also those further afield “downstream” of the Cumbrian Mud Patch. ………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………

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1: West Cumbria Mining’s proposed excavation/extraction methods 1:1 West Cumbria Mining propose to use a “run out and pocket pillar” excavation system, deploying large hydraulically driven machinery, cutting and collecting the coal and transporting it away from the face on a conveyor belt. This form of continuous mechanical mining uses mobile roof supports to support the roof of the galleries “Our goal is that Woodhouse Colliery will lead the UK coal industry into the mid-21st Century, utilising modern, well proven mining methods to achieve a steady-state production of 3.1 million tonnes per annum Run-of-Mine. Run-out and Pocket extraction will be the chosen mining method as this is a proven, highly versatile coal mining method that takes advantage of advancements in mining technology to mitigate risks associated with the Cumbrian Coal fields.”

The “Run out and Pocket” technique includes: •

Bolter Miners develop the gate roads, for the panel

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A Bolter Miner will then drive a run-out roadway

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A Continuous Miner subsequently cuts chevron cut pockets into the pillars

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The roof is supported by mobile supports

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Shuttle cars continuously move coal from the respective miners to the Feeder Breaker

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Once coal has passed through the Feeder Breaker it falls onto the underground conveyor belt to be taken to surface.

Fig : West Cumbria Mining’s diagram of proposed mining/extraction method

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1:2 According to West Cumbria Mining the only expected potential impact down to the low water line could be subsidence following mining works; however, WCM have included a ‘no-mine zone’ beneath St Bees Head and the MCZ, to ensure that there will be no subsidence in this zone.

Fig 2: The Cumbria Coast MCZ (extends 1 km offshore)

Fig3: The sub-sea area proposed for the mining/extraction zone of the proposed Woodhouse colliery extends for approximately 8kms offshore and southwards towards the Sellafield site N.B. From the content of WCMs commentary above, it can be seen that the proposed “no mining” zone will make little impact on WCMs proposed mining activity as the great majority of the proposed underground workings of the proposed Woodhouse mine are scheduled to be beneath the seabed immediately to the west of St Bees Head as shown in the map above.

N.B. From the WCM commentary, it can be also be deduced that there may be a potential subsidence in areas other than those beneath St Bees Head and the MCZ. This will include the extensive, 8km wide “sub-sea area” shown in the map.

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2: Summary of Mining subsidence and fault reactivation 2:1 There are two types of surface subsidence associated with underground mining: a: trough subsidence, a relatively gentle, large-area depression of the terrain, and chimney or sinkhole subsidence, which is manifested by conical depressions. b: residual subsidence is a time delayed form that can result from roof failure, pillar failure, squeezes and/or punching, or compaction and consolidation of collapsed zones.

Abandoned mine openings can remain stable as long as the stresses upon them do not exceed the strength of the rock in the roof, floor, pillar, or backfilled zones.

2:2 Commenting on subsidence issues in northern England a recent report notes that centuries of coal mining in parts of the region have left a legacy of surface collapse and instability. Even subsidence due to modern coal mining, which is generally predictable and manageable, may become less so if the fill material has a low bearing capacity and so allows further incremental collapse. More significantly, the extent and nature of earlier mining, particularly shallow pillar and stall working, may be less well known. Voids created during this early work may remain open long after abandonment, with collapse taking place unpredictably over many years. Should such old workings be present above modern workings, the subsidence difficulties are compounded. Although reliable plans exist for a high proportion of the region’s coal workings, small but significant areas of very old workings near seam outcrops are unrecorded.

(REF: http://earthwise.bgs.ac.uk/index.php/Geological hazards, geology and man, Northern England)

2:3 In this context there appears to be a general consensus that the sub-sea area designated for the WCM workings are indeed poorly mapped/charted and that there may be a risk of running into, or close to, old workings of the West Cumbria coalfield. Note also that later paragraphs make it clear that the Cumbrian coalfield has a high density of faulting. Certainly there has been no well supported claim that the area is well mapped and adequately charted. This is an issue of some importance as there is general agreement that where new mining activity occurs close to old workings, the risk of subsidence/fault re-activation is increased.

2:4 Many studies demonstrate that where the regional geology is naturally faulted, extractive mining activity may activate the existing faults and generate subsidence leading to large scarps (sharp slopes). One such scarp in the USA was noted to have been 1 metre high and 16km long. (REF: “A Review of International cases of fault re-activation during Mining Subsidence and Fluid Extraction”: Donelly. L.J. et al’. Quarterly Journal of Engineering, Geology and Hydrogeology. 42. 73-94. March 2009)

2:5 Other studies comment that the impact of coal mining techniques has been observed to generate subsidence due to fault re-activation and that this impact has been observed over many years in faulted coal fields in the UK. There appears to be a UK widespread consensus that such subsidence may cause marked deformation and severe damage to the surface morphology through the disruption of gradients and land forms.

(REF: “Longwall Mining – Induced fault re-activation and delayed subsidence ground movement in British coalfields. ” Donelly. L.J. et al’. British Geological Society)

2:6 Some forms of surface deformation, known as “trough subsidence” can appear relatively soon after continuous extraction, and are often completed within weeks to months of the activity. This is often followed, shortly afterwards, by a period of delayed subsidence know as “residual subsidence.

2:7 Where faults are not a major feature of the coalfield, residual subsidence can be completed in a few months, however in more faulted areas residual subsidence may still occur more than 2 years after mining has ceased. Of relevance to the Cumbrian coalfield, is the fact that this report noted that in heavily faulted abandoned or partially active coalfields, ground movements in the vicinity of fault outcrops may occur many years after mining has ceased (residual subsidence).

(REF: “Longwall Mining – Induced fault re-

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activation and delayed subsidence ground movement in British coalfields. � Donelly. L.J. et al’.

British Geological Society)

FIG 4: Trough subsidence cross section of surface deformation (dry land)

Fig 5: Modes of subsidence in coal mines

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BGS comments on Cumbrian coalfield seismicity and coal mining

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Fig 6: Seabed and terrestrial Seismicity around the Cumbrian Coast

3:1 According to the British Geological Society, earthquakes and seismic activity induced by coal mining are seen often on the widely spaced seismograph stations operated by the British Geological Survey. Such seismic phenomena are characterized by shallow depths of focus, proximity to current workings, repeatable signals, and good correlation with mining activity.

3:2 In relation to Cumbria, the BGS comments that “However, underground mines in this coalfield have always suffered from severe geological problems, particularly faulting, and the high methane content of the seams is known to be a problem.”

(REF: “UK Coal Resource for New Exploitation Technologies Final Report Sustainable Energy & Geophysical Surveys Programme.” Commissioned Report CR/04/015N. BGS & NERC. 2004)

3:3 Commenting on the availability of coal bed methane levels within the Cumbrian coalfields, a 2010 report noted that, despite the fact that “methane was historically used as a power source at Haig Colliery, Whitehaven .......... in the Cumbrian Coalfield extensive mining of coal and the high density of faulting, have limited any exploitable resource.”

(REF: “Managing Radioactive Waste Safely: Initial Geological Unsuitability Screening of West Cumbria”. BGS & NERC. 2010)

3:4 It is clear that, in the view of the UK expert British Geological Society, the Cumbrian coalfields are beset by “severe geological problems”, “particularly faulting”, to such a high degree that historically “the density of such faulting” has “limited any exploitable resource”. In this context WCM’s confidence that their proposed 3 million ton per annum extraction, extended for a 50 year period, can be carried forward without increasing the risk of subsidence or fault re-activation is

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contra-indicated in the context of the BGS commentary and the evidence which will be presented in the immediately following sections.

4: The possible outcomes of subsidence seismicity in the WCM designated sub-sea mining area 4:1 There is now a long term consensus that seismic activity may be generated by coal mining. Since the early 1900s various forms of surface seismic networks have been established to monitor induced earthquakes related to coal mining activity. The long term evidence strongly implies that the risk of such subsidence may be increased where coalfields are heavily faulted. It is widely reported that the west Cumbrian coalfield is heavily faulted and susceptible to subsidence (induced seismic activity) as a result of coal extraction.

4:2 While subsidence is one effect that occurs above a deep mine, another effect occurs below a deep mine, due to the redistribution of the existing tectonic stress field disturbed by the excavation process. High stresses exist inside tectonic plates and they are sensitive to any perturbations. The perturbation, or disturbance, of the stress field reaches beneath the excavations, mainly due to the removal of coal as well as the water that is extracted in order to keep the deep shafts dry.

4:3 There is a wide consensus that such “mass removal” causes an “unload” of the continental crust. In the case of mining, an unload is the reduction of weight in a certain area following the extraction of coal and water in a colliery. If it has enough time, the tectonic plate reacts to this unload by forming a small deformation. If it does not have enough time because the rate of mass removal is too high and too fast , a fault zone can be reactivated or newly created and an abrupt reaction is induced - an earthquake is produced.

4:4 A 2012 report about induced seismicity in the Newcastle coalfield, Australia, shows that there is a statistically significant relationship between man-made “mass removal” geo-engineering projects (such as mining) and earthquakes observed in the close vicinity (fewer than 50 kilometres) of the geo-engineering activities. Most of the earthquakes examined in the study were induced or triggered several years after the geo-engineering activities had started.

N:B It can be postulated that the proposed extraction (over the 50 year operating lifespan of the Woodhouse Colliery) of 150 million tonnes of coal (136 million cubic metres: greater than the volume of Wastwater Lake) is equivalent to a “mass removal” potentially capable of causing such an “upload” and inducing an earthquake in the manner described in para 4:3 above

4:5 In concluding the 2012 study, recommendations are provided for identifying humanmade earthquakes. Locations of geo-engineering operations should be monitored and the seismic events should be analyzed based on the following model types a) physics-based, b) statistical, c) source mechanisms. Such models can discriminate between human-caused and natural seismic activity. At the same time hazard mapping in space and time is crucial to provide information to urban planners. In the case of Newcastle, coal mining was, is, and will be a part of this region. The associated hazards need to be addressed and riskmitigation measures need to be implemented, including reinforcement of buildings or changes in urban planning.

NB: it is notable the Cumbria County Council has NOT initiated any such studies for West Cumbria Mining’s designated sub-sea mining area.

4:6 Many studies report that the risks associated with human induced earthquakes need to be addressed when large-scale geo-engineering projects are planned. Ensuring sustainable geo-engineering practices is especially important in the regions of high population densities.

(REF:

“Earthquakes and mining - how humans create seismic activity”. The Conversation: Christian Klose. Adjunct Research Scientist/Senior Research Scientist at Think Geohazards June 21, 2012)

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4:7 In the context of the available empirical evidence, it is evident that “mass removal” mining has the potential to generate fault re-activation earthquakes and that there is strong evidence that the speed of the “mass removal” and the degree of faulting present in the coalfield may increase the risk of fault re-activation quakes. It is vitally important that sustainable geo-engineering practices and monitoring are initiated in the case of potential seabed human induced earthquakes, where the seabeds are known to carry large burdens of anthropogenic pollutants posing a potential health threat/risk to adjacent coastal populations and where induced earthquakes may take place in the vicinity of sensitive and dangerous installations.

5: Seismically induced liquefaction 5:1 Although the most likely form of seabed distortion arising from any subsidence in the old or new workings of the sub-sea section of the west Cumbrian coalfields, is some form of vertical (downward displacement) there is good evidence that there will be a number of other accompanying features.

Due to the difficulty of underwater surveying, there are a limited number of seismic damage investigations on the sea floor compared with those on land. However, from the existing cases, there is a consensus that seismically induced seabed liquefaction can be so extreme as to cause serious damage to marine engineering structures and there is good evidence that under cyclic loading, such as storm waves and seismic activity, the strength and stiffness of seabed muds and soft clays will decrease and liquefaction may occur 5:2 It is clear from recent history that earthquakes with their origin beneath the seabed, are perfectly capable of causing impacts at some distance from the point of origin including the adjacent terrestrial environment.

While significant advances have been made in the study of onshore seismic liquefaction and anti-liquefaction measures, regretably this has not been the case with submarine events. However, studies report that the ocean environment is more complicated than the onshore one and there is empirical evidence that earthquake-induced seabed liquefaction has some unique features. For example, the dynamic response of the seawater during an earthquake event is known to have caused liquefaction in the seabed .

(REF: “Review Features of Earthquake-Induced Seabed Liquefaction and Mitigation Strategies of Novel Marine Structures”. Yu Huang et al’. Journal of Marine Science. April 2020

5:3 The British Geological Society has reported that “An earthquake on 15 February 1865 affected only a very small area around Barrow-in-Furness, yet had a very high epicentral intensity (8 EMS). Considerable damage was caused at the village of Rampside.

On the sands near Rampside, liquefaction effects such as sand fountaining and quicksand were observed. Conventional wisdom states that liquefaction only occurs with large earthquakes, but this event shows that very vulnerable sediments can liquefy even with a small earthquake if the intensity is high enough.” (REF: UK EARTHQUAKE MONITORING 1996/97 BGS Seismic Monitoring and Information Service Eighth Annual Report. Publication Summaries. ANNEX G. Page 45)

5:4 Further commentary on the Barrow in Furness event has been supplied by a 1998 paper which noted that “An earthquake in 1865 in the northwest of England suggests that a sufficiently shallow small event can also produce liquefaction. The effects are welldocumented in historical sources and include sand “fountaining”. Modern investigation is confined to documentary evidence owing to the tidal environment of the area where liquefaction occurred. Analysis shows that the felt area of the earthquake was probably only about 200 km2; however, heavy damage occurred in the village of Rampside and the maximum intensity is assessed at 8. Liquefaction is not uncommon at this intensity, but such a high intensity is not usually produced by such small earthquakes.”

5:5 The paper was careful to record the fact that such high intensity and liquefaction phenomena are usually associated only with relatively large magnitude earthquakes, but that in this case the magnitude was probably in the range 2.5–3.5 M L .

REF: “The Barrow-in-Furness Earthquake of 15 February 1865: Liquefaction from a Very Small

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Magnitude Event.” R.M.W. Musson. Pure & Applied Geophysics. 152(4): pps 733-745. Nov’ 1988

5:6 Para 5:5 above provides additional support to a very detailed and fully referenced 2018 report, that the terrestrial Sellafield site, and possibly Drigg, may be at risk from earthquake induced liquefaction impacts. This study into geotechnical issues relating to the proposed MOORSIDE NPP reported that “The geotechnical engineering behaviour of a sequence of glacial deposits on the Sellafield nuclear site had been evaluated together with their susceptibility to potential liquefaction under certain seismic load conditions.

The evaluation identified that layers of very loose to loose deposits within the ice sheet marginal land system are particularly susceptible to liquefaction under specified seismic loading conditions”.

5:7 The 2018 report further comments that “The sequence is characterised by very loose sands and and gravels, silty and clayey sands and gravels with various inter-bedded layers of firm clay at various depths. Most of the sands and gravels are water saturated.”

5:8 The report concluded that “The results of the assessments indicated a potential high risk for liquefaction for horizontal ground acceleration events. .............In such circumstances large differential settlement and ground deformation are highly probable during a seismic event of magnitude 6. In such circumstances, engineered remediation measures are required to keep these deformations within the tolerable limits for the proposed nuclear structures” REF: “The susceptibility of glacigenic deposits to liquefaction under seismic loading conditions: a case study relating to nuclear site characterization in West Cumbria.” Martin Cross et al. Proceedings of the Yorkshire Geological Society: Published online September 18, 2018

5:9 In the context of the 2018 report it is highly relevant to note that this work was specifically considering the potential impacts on the proposed NEW BUILD Moorside NPP and that it’s scoping clearly did not include the necessity to comment on the implications to the Sellafield works (much of which was constructed way back in the 1950s/1960s) or to the nearby DRIGG “low level” radioactive waste repository.

It is also relevant to reflect that a lower magnitude seismic event, such as the magnitude 2.5 to 3.5 Barrow earthquake, may also be capable of generating sufficient liquefaction to cause damage to the older Sellafield/Windscale infrastructure such as cooling ponds, pipelines, rad’ waste storage sites etc.

5:10 It is clear from the evidence of academic research, presented in peer reviewed journals, that the regional geology around the Moorside and Sellafield (operating and proposed) nuclear sites is glacial in origin and prone to liquefaction in the event of seismicity. In conjunction with the report of the Barrow earthquake and it’s liquefaction event under the impact of “such a small earthquake” (reported as “probably in the range 2.5-3.5ml), a 2018 report provides sufficient empirical evidence to support the proposal that a significant subsidence or fault re-activation in the WCM designated subsea mining zone may offer the potential to generate a seismic event of sufficient magnitude to create liquefaction in the Sellafield region glacial deposits.

6: Distortion of seabed morphology 6:1 Slower, less dramatic forms of seabed morphology distortion may also occur, with incremental shifts creating smaller short term individual modifications at the mm or cm scale, which cumulatively over time will become more significant. Such forms of seabed

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surface morphological change will eventually create surface features such as the scarp, 1 metre high and 16km long, referenced in para 2:4 (above), or the “troughs” and “crownholes” set out in Fig 5.

Fig 7 : Seabed morphological change : “trough” formation in a liquid hydrocarbon field

6:2 The subsidence induced creation of each of these new seabed features will modify both seabed and bottom water current and water body movements and velocities, and, if sufficiently large, may also have an impact on surface water movements. The extent and range of such modifications will be dependent upon the extent, range and speed of the subsidence event.

6:3 Should subsidence occur at speed and/or in high volume or mass, then it is possible that the disturbance of surrounding seabed sediment may give rise to a cloud/ plume of sedimentary material generated by vibration in the near and intermediate vicinity of the event.

6:4 Under both 6:2 and 6:3 scenarios, un-consolidated and consolidated seabed sediments will be ejected into the water column, as they are during any other event which disturbs the seabed (trawling, passage overhead of large storm waves, earthquakes etc). Those sediments will then become entrained in the regional water column, along with their load of ad-sorbed pollution and the polluted interstitial (pore) water of the previously sequestered sedimentary deposit, and be transported through the near field, intermediate and far field marine environments.

6:5 Following such an event the sedimentary and interstitial pollutants will be made more widely bio-available to marine biota which will inevitably generate a process of bioaccumulation in some marine species. This process is likely to occur in both plant and animal life with the greatest concentrations inevitably occurring in species at higher levels via a number of well attested and empirically proved mechanisms and pathways: including food chains and (following sea–to-air transfer processes) inhalation and transfer to land.

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6:6 It is evident that any subsidence within the WCM designated seabed mining zone will generate some form and degree of seabed morphological distortion. It is equally evident that any such seabed distortion will remobilise previously sequestered seabed sediments, and their associated pollutants, which will subsequently be transported and re-distributed through the regional marine and coastal environments.

It is inevitable that such re-mobilisation and re-distribution will expose marine wildlife and human coastal populations and stakeholders to some degree of exposure doses to those pollutants via a number of mechanisms and pathways.

7: Cumbria County Council Subsidence Monitoring 7:1 A report laid before Cumbria County Council has discussed the methodology for subsidence monitoring. This report states that no working of minerals shall take place until a subsidence monitoring scheme has been submitted to and approved in writing by the Mineral Planning Authority. It also recommends that the scheme shall include the following: a) The methodology for subsidence monitoring including establishing the maximum zone of influence of onshore mining, the methods for recording existing ground levels, method for monitoring changes in ground levels, equipment to be utilised and duration of monitoring following the cessation of onshore mining; b) The subsidence monitoring locations and the rationale for the number of monitoring points and the locations selected; c) The frequency of subsidence monitoring, and the rationale for the frequency selected; d) The arrangements for reporting the outcome of subsidence monitoring to the Mineral Planning Authority which routinely shall be no less than annually; e) The method for the derivation of trigger subsidence levels at sensitive receptors which would represent a subsidence event; and f) Proposals for increasing the frequency of subsidence monitoring and for the reporting of that increased frequency of monitoring to the Mineral Planning Authority in the event that a subsidence event occurs. Surface subsidence monitoring and reporting shall be undertaken in accordance with the approved monitoring and reporting scheme.

7:2 It can be seen from the above that the entire focus of subsidence monitoring is (and has always been) the issue of subsidence of terrestrial surfaces due to onshore mining activity. There is no mention of seabed surface morphology subsidence. It can therefore be assumed that seabed subsidence is NOT an issue of any concern for any of the relevant authorities 7:3 Later sections of the report address additional subsidence monitoring issues as follows: Subsidence – Investigation and reporting , which advises that coal production within the zone of influence of the sensitive receptor shall be suspended until a subsidence investigation has been completed and that the subsidence investigation shall determine the reason(s) for the subsidence event. The investigation shall review the mining activities taking place prior to the subsidence event being detected and determine which of these activities led to the subsidence event occurring. The findings of the investigation shall be set out in a subsidence investigation report which shall also identify the mitigation measures and a programme to be adopted to prevent a reoccurrence of a subsidence event. Where a subsidence investigation report has been concluded it shall be submitted to and approved in writing by the Mineral Planning Authority. Any mitigation measures shall be carried out in accordance with the Mineral Planning Authority’s written approval and the approved programme. Reason: To ensure that subsidence is monitored,

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investigated and mitigated in accordance with policy DC13 of the Cumbria Minerals and Waste Local Plan. N.B. As with the previous section, it is clear that none of the advice is related to subsea mining or subsidence.

7:4 The report goes on to advise on Subsidence Mitigation : and states that Coal mining shall only recommence within the zone of influence of the sensitive receptor after the Mineral Planning Authority provide written notification to confirm approval of the investigation report and that the proposed mitigation measures are acceptable. Coal mining within the zone of influence of the sensitive receptor which was the subject of the subsidence event shall thereafter only take place in accordance with the mitigation measures approved within the subsidence investigation report. (REF:(http:// councilportal.cumbria.gov.uk/documents/s90108committee%20report.PDF) N.B. As with the previous section, it is clear that none of the advice is related to subsea mining or subsidence

7:5 From the above it is clear that seabed subsidence issues ARE NOT and NEVER HAVE BEEN an issue of interest to Cumbria Council, Regional Mineral Management Boards, the Coal Mining Authority or any other relevant regional or national body. In that context it appears that there is no official and coherent record of seabed subsidence issues in the area of the historical and proposed West Cumbrian coalfield mine workings.

7:6 Clearly there has been a long term historical failure to collect any data, information or record of seabed subsidence in the St Bees Head proposed offshore mining zone. This may have been of relatively little significance in the centuries before WW2. However during the 1950s the Windscale (later renamed the Sellafield ) site began to discharge industrial quantities of man-made radioactivity into the local/ regional sea area, and this action has subsequently created a vital necessity to carry out seabed subsidence studies and to generate seabed subsidence monitoring plans and mitigation strategies and to look at the potential environmental and public health implications of seabed subsidence and morphological change events.

It is concluded that the apparent “do nothing” policy of Cumbria County Council in this context is contra-indicated by both the potential likelihood of seabed subsidence in the context of the rapid “mass removal” and the risk of the re-mobilisation of radiologically contaminated seabed sediments in the event of any subsidence or seismicity.

8: The application of known Seabed subsidence monitoring techniques 8:1 During the research and writing of this Briefing little evidence of detailed research into the mechanisms or impacts of seabed subsidence in sub-sea coalfields has been uncovered. However, it is clear that there is a growing field of research into the impacts of crude oil extraction from sub-sea oil reserves. It is highly relevant to note that this research (focussed on the safety and operational viability of drilling platforms, pipelines and other infrastructure) describes features of seabed subsidence in oil fields across the globe, from the North Sea to Venezuela and the West coast of the USA, which are very similar to those terrestrial subsidence issues related to coal field extraction. (REF: “Compaction and subsidence issues within the petroleum industry: From Wilmington to Ekofisk and beyond”. Nagel.N. Physics and Chemistry of the Earth Part A Solid Earth and Geodesy. 26(1-2):3-14 · December 2001)

8:2 A 2015 study from Italy has reviewed subsidence monitoring techniques for offshore applications and noted that for new offshore hydrocarbon developments in Italian

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waters it is mandatory for developers to submit a monitoring plan, to the Italian authorities, which will measure and analyse real time subsidence activity and evolution.

8:3 The study noted that although many tools are available for subsidence monitoring onshore, few are available for offshore monitoring. To fill the gap ENI (Ente Nazionale Idrocarburi) started a research programme, principally in collaboration with three companies, to generate a monitoring system tool to measure seafloor subsidence.

The tool, according to ENI design technical-specification, would be a robust long pipeline or cable, with a variable or constant outside diameter (less than or equal to 100mm) and interval spaced measuring points. The design specifications for the first prototype were: to detect 1mm altitude variation, to work up to 100m water depth and investigation length of 3km.

8:4 The Italian study reported that advanced feasibility studies have been carried out and that five designs (using three fundamental measurements concepts and five measurement tools) were explored: cable shape changes measured by cable strain using fibre optics; cable inclination measured using tilt meters and measured using fibre optics, and internal cable altitude-dependent pressure changes measured using fibre optics and measured using pressure transducers at discrete intervals along the hydraulic system. Each design tool was analysed and a rank ordering of preferences was performed. The third method (measurement of pressure changes) was deemed most feasible and building of the first prototype of the tool to be installed in an offshore field was underway in 2015. (REF: “Prevention and mitigation of natural and anthropogenic hazards due to land subsidence: Subsidence monitoring system for offshore applications: technology scouting and feasibility studies.� R. Miandro et al’. Proc. IAHS. 372, 323-330. 2015)

8:5 Since the completion of the study referenced above, autonomous seabed subsidence monitoring systems have been developed and installed by other companies in many sub-sea hydrocarbon extraction scenarios. Seabed deformation monitoring is reported to be moving into new realms of capability, as self-calibration, autonomous deployment and data collection open up new possibilities for extending the life of oil fields.

8:6 It is reported that, based on operational experience, the precision of seabed settlement monitoring equipment is undergoing constant improvement. Driven by financial considerations and regulatory pressure work to enable regular in-situ calibration, as well as a research programme to select and pre-characterize the best pressure sensors, and to localize the positions of equipment from surface drones, companies are now able to achieve close to 1cm/year measurement sensitivity. (REF: https://www.oedigital.com/ news/466109-seabed-surveillance-enters-age-of-autonomy)

8:7 Despite the absence of coalfield specific data covering issues of seabed subsidence, and the failure of Cumbria County Council, the Mineral Planning Authority and the Coal Mining Authority to undertake or mandate any such seabed subsidence research or monitoring, there is sufficient evidence to confirm that the modes of seabed subsidence and the subsequent morphological distortions will be similar to those recorded on terrestrial land forms.

The existence of the above referenced seabed subsidence measuring systems means that Cumbria County Council and other mineral extraction regulatory agencies can now insist that, if WCM are permitted to mine coal in their designated sub-sea mining zone, they must (as is mandatory elsewhere) insist on the installation of seabed subsidence

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monitoring systems to check for any post extraction impact on the adjacent seabed morphology.

Previous sections of this Briefing have explained how, and why, such morphological impacts are likely to occur in the sub-sea sections of the west Cumbrian coalfield 9: “Backfilling”: WCMs proposed mitigation of seabed subsidence 9:1.

WCM’s documentation has stated that their mining activity will annually generate about 150,000 tonnes of “reject” material. WCM state that : “The reject will be blended with water and a binder (e.g. cement) and the resultant paste material will be pumped back underground and placed directly behind a working panel as it is mined. When used, the paste will fill an estimated 65 % of the void space behind a worked panel. The use of the paste backfill will significantly increase the stability of mined-out areas and subsidence over backfilled panels will be reduced by at least 65 %.

This applies to both single panels and to groups of panels. For example, for a single panel with 65 % backfill the maximum vertical displacement will be reduced from 21 cm to 9 cm. There will be sufficient paste produced each year to fill two of the eight panels mined each year, i.e. 25 % of panels will be backfilled. Backfill will be primarily targeted to sensitive areas including all onshore panels and selected panels close to the MCZ.” 9:2 From this statement it evident that WCM intend little or no remedial action backfilling in their designated sub-sea mining zone and that backfilling will be strictly limited to the mining zones underneath the MCZ. The implication of this commentary is that even WCM accept that some subsidence may occur and that backfilling as a remedial measure beneath the MCZ and onshore may be necessary.

9:3 It is further evident that WCM’s estimation of the 150,000 ton volume of “reject” material which will be available for use in backfill mitigation would clearly be insufficient to backfill the approximately 136 million cubic metre void space to be created by the proposed extraction of the coal 9:4 A January 2019 review of backfilling issues noted that the waste products from the mining process, mixed with cement grouting and high water content materials are available for use in backfilling activity. The 2019 review also commented that such techniques have been traditionally used for shallow mines but that different approaches are required for “deep” mines operating below the 300 metres depth and that “As a result, it is required to investigate new backfill materials suited for the deep high-stress environment”.

9:5 The review then goes on to describe those stresses as follows: "Significant changes in the deep mining environment mean that deep backfill mining faces many major technical problems. Firstly, mechanisms of strata movement in backfill mining change under high in-situ stress conditions. Secondly, high ground temperatures may change the mechanical properties of backfill material. Thirdly, high gas causes difficulties in coal mining and gas extraction. Fourth, seepage characteristics of deep backfill coal and rock masses are unknown. Fifth, high-intensity mining restricts the arrangement of the integrated mining system. How to deal with these challenges, innovatively solving the scientific problem of deep backfill mining, developing basic theories for controlling strata movement relating to backfill mining, forming green mining systems, improving the dressing of deep coal, and backfilling of goafs, warrants further research." (REF: “Properties and Application of Backfill Materials in Coal Mines in China.”Jixiong Zhang.

Minerals: 17 January 2019)

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9:6 A follow on research paper from November 2019 reports a series of studies to investigate the effectiveness of “cemented paste backfills” proposed for deployment in deep mines. This study noted that Cement Paste Backfill (CPB) were shown to be subject to decay as a result of temperature, physical and chemical reactions, with increased temperature accelerating the chemical reaction. Specifically it was noted that : 9:7 “the high temperature caused by oxidative heat release, blasting operations, and deep-well mining for underground coal along with the stress of overlying strata and deterioration by chemical substances such as acids, alkalis, and salts contained in groundwater cause damage to the structure of cemented paste backfill (CPB). The effect is to reduce or eliminate CPB effectiveness, which in turn affects the stability of the goaf.”

9:8 The paper concluded that it’s “experimental study on the mechanical properties of CPB under temperature-chemical (TC) coupling has important theoretical significance and practical engineering value for predicting stability in filling engineering.”

(REF: “Experimental Study on Mechanical Properties of Cemented Paste Backfill under TemperatureChemical Coupling Conditions”. Yin Liu et al’. Advances in Material Sciences and Engineering.

Volume 2019. 16th Nov.)

9:9 It is clear from the above referenced reports that “backfilling” using methods such as those proposed by WCM, for the designated mining area beneath the MCZ, are both outdated and less than perfect, and contain a number of inherent weaknesses which have generated negative commentary from contemporary observers and researchers who have warned of the need for “further research” and increased experimental study on the mechanical properties of backfill technology.

10: Fate and behaviour of marine radioactivity 10:1 The sea area under discussion in this Briefing includes the MCZ of the Cumbrian coast around St Bees Head, the seabed in the area of the WCM designated sub-sea mining zone and the Cumbrian Mud Patch extending from inside the Solway Firth as far south as the coastal zone offshore of the Sellafield and Drigg nuclear sites. Due to the long history of high volume, and highly concentrated discharges of liquid and particulate radioactivity into this sea area (early 1950s to the present day) it is renowned as the UK’s most radioactive sea area.

10:2 When discharges of industrial quantities of radio nuclide laden liquid wastes to sea commenced in the early 1950s, they were licensed and permitted in the absence of any empirical knowledge about the behaviour and end fate of man-made radioactivity in marine environments or of the environmental parameters that might govern and influence that behaviour. Accordingly the IAEA and other military and civil nuclear interests concocted a hypothesis, based on very limited laboratory observations, which they deployed to justify discharges to sea.

10:3 The IAEA (et alia) hypothesis postulated that the so called “conservative” nuclides such as Caesium and Tritium, dissolved into the discharged liquid radioactive waste would remain in the liquid phase in the sea and be diluted and dispersed to “infinity” or at least background levels.... the much quoted “dilute and disperse” policy.

10:4 The nuclear industry further proposed that long lived, transuranic nuclides such as Plutonium, Americium etc, would leach out of the liquid phase and become preferentially ad-sorbed to the surface of sedimentary particles in the water column, sink to the seabed and there remain permanently bound and immobilised in seabed (subtidal) deposits and there remain “sequestered” and isolated from human populations and the environment.

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10:5 This hypothesis supported the adoption of the proposal that the behaviour of radioactive wastes discharged into marine environments was such that “they can be diluted and dispersed so that the radiation to which any single individual would be subjected would be negligible”. (REF: “Disposal of Radioactive Wastes: a review of IAEA efforts to assure safety”. IAEA Bulletin: Vol 03. Issue 3. 1961 page 3).

10:6 It was upon this hypothesis that the scientific and ethical justifications for the sea disposal of radioactive wastes were based and permission for the discharge of liquid radioactive wastes from Sellafield was granted. In later years, as the UK’s civil nuclear programme continued to be expanded, the hypothesis also provided the scientific justification for the sea disposal of radioactive wastes from the UK civil nuclear power stations, the great majority of which were sited on (or close to) the UK coastline.

10:7 However, as both academic and nuclear industry research observed the behaviour and fate of the very large quantities of radioactivity discharged to sea through the following decades the true facts of the behaviour and fate of marine radioactivity began to emerge.

10:8 At the 1977 Windscale Inquiry it was confirmed that actinide laden radioactively contaminated seabed sediments in the Sellafield region were not immobile but subject to a host of disturbances and recycling events including dredging, trawling, storms and seismic activity. On this basis it can be seen that a percentage of such sediment associated radioactivity has, and is being actively transported around the Irish Sea while the remainder is temporarily “sequestered” in the seabed but subject to any future disturbance mechanisms such as storm, wave and seismic activity.

10:9 It was also discovered that a percentage of the so called “conservative” nuclides did not necessarily remain dissolved in liquid form in the water column, but that they too could become incorporated into organic particles suspended in the water column and that they too could be deposited out into sedimentary environments where, along with the actinides they could be temporarily sequestered, but subsequently recycled back into the environment by dredging, trawling storm and seismic activity.

10:10 Although the authorities have (post 1977) constructed models of Irish Sea sediment movements, these lack specificity and cover only average effects, thus to date there has been discernible attempt to describe the likely outcomes of seismic activity on the seabed of the N.East basin of the Irish Sea. This has been exacerbated by incomplete data on the various relevant parameters such as long term residual current movements, the depth of fine sediments and their distribution in the Sellafield area and precise characterisation of the distribution of radioactivity within the sea area.

10:11 It is clear from the above that all forms of radioactivity associated with sedimentary deposits are readily mobilised in the North Eastern basin of the Irish Sea and available for subsequent re-incorporation in the fine sediment deposits of the Cumbrian Mud Patch. This includes a percentage of the “conservative” radio nuclides still dissolved in the water column but present in submarine mud deposits as “pore” or “interstitial” water.

11: Radioactivity in the Cumbrian Mud Patch: St Bees Head & the seabed of the WCM designated sub-sea mining zone 11:1 There is a broad consensus that some radio nuclides readily dissolve into water and remain there after discharge. However, as referenced above, some caution should be

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taken of this generalised view in the context of relatively new (post 2000) evidence of the ability of such water soluble nuclides to become organically bound to organic particles (micro organisms, plant material particles etc) which may sediment out of the water column and become incorporated into marine sediment deposits.

11:2 There is a general consensus from the nuclear industry and UK regulatory agencies that radio nuclides with a strong affinity for sediment particles are quickly removed from the water column by scavenging processes onto suspended particulate matter, and accumulate in fine-grain deposits. In the eastern Irish Sea, muddy sediments are confined to the Cumbrian Mud Patch, an extensive offshore mudflat lying parallel to the Cumbrian coast, off Sellafield, which acts as a very efficient sink for particle-reactive radio nuclides, such as transuranics.

11:3 In the case of the transuranics a number of estimates of the discharges of these nuclides have been put forward. Based on nuclear industry figures A 2005 study reported that an estimated 120TBq of Pu 238, 611TBq of Pu 239/240, and 22 PBq of Pu 241 have been discharged to the Irish Sea during the period 1952-2000. (REF: “Diagenetic reactivity

of the plutonium in marine anoxic sediments (Cumbrian mud patch – eastern Irish Sea). Gouzy.

A. Et al’. Radioprotection, Suppl. 1, vol. 40 (2005) S541-S547) N.B 1 Tbq = 1,000,000,000,000 Bqs

11:4 However, outside the nuclear industry, there is some doubt about the accuracy and precision of industry reported discharges. During his preparation of the COMARE report into childhood leukaemia in West Cumbria, Sir Douglas Black was informed by the nuclear industry that only 400 grams of uranium had been discharged from the Sellafield site between 1952 and 1955. This claim was later discredited when two scientists who had worked at the site in the 1950s confirmed that this figure was at least 40 times too low.

(REF: “The Sellafield Discharges”. Bunyard.P. The Ecologist, Vol 16. Nos 4 & 5, 1968.p 188)

11:5 Similar omissions, mis-calculations and worse, have confounded the issue of discharge volumes and concentrations since the very beginning of such discharges. These include the numerous un-monitored long term leaks from reactors and cooling ponds at UK nuclear licensed sites which have led to un-licensed and un-quantified discharges of an unknown variety of radio-nuclides for unquantifiable time periods.

11:6 When we additionally factor in the fact that continuous liquid discharge streams are often sampled on an occasional basis only (i.e. there is limited continuous sampling/ monitoring) it becomes increasingly evident that there are strong reasons for assuming that the figures given by nuclear industry, nuclear regulators and the agencies of pro nuclear governments are incomplete and at the very best only to be taken as very weak “guesstimates” with an incomplete basis in empirical observation or record keeping.

11:7 In addition, all of the statements issued by nuclear industry, nuclear regulators and our pro nuclear government in an attempt to quantify and monitor the total amount of radioactivity discharged into the UK coastal waters routinely, and without fail, provide only the briefest of lists of the radio-nuclides they are prepared to quantify.

Given that it is widely known that the Sellafield site discharges at least 70 discrete radio nuclides to sea, and that most of the UK nuclear power plants discharge at least 60 radio nuclides to sea, it is clear that statements fall drastically short of the full inventory of sea discharges.

11:8 Despite the very many major shortcomings of nuclear industry and regulator sampling, monitoring and quantification processes it is on the basis of these practices

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that the nuclear industry and its supporters in the UK consistently refer to discharges to sea from UK licensed nuclear sites as “low level”.

However, there are many mechanisms for the re-concentration of man made radioactivity in marine, coastal and estuarine environments as can be seen from the enormous quantities and concentrations of some radio nuclides reported in environmental samples from UK marine environments. Nowhere is this more obvious than in the Irish Sea where (according to RIFE-24 monitoring report for 2018) the concentration of Caesium 137 in one kg of mud from Carlton Marsh (nr Drigg) was around 1,800 Bq. In the context of the total volume of mud in Carlton Marsh, this clearly must represent a huge “aggregated” radioactivity reserve on a marshland approximately 50 acres in extent.

(REF: “Radioactvity in Food and the Environment, 2018”. RIFE-24. October 2019. Fig 2.25: page 65)

12: Sellafield, the Cumbrian Mud Patch & quantification of radioactivity 12:1 The Cumbrian Mud Patch is, according to the British Geological Survey, an area of muddy sediments which lies off the Cumbrian coast in a zone of low tidal energy. This is surrounded by sandy sediments with the mean grain size increasing eastwards towards the shore, westwards towards the Isle of Man, and northwards towards the Solway Firth, associated with increasing tidal and/or wave energy. The muddy sediments represent both marine and post-glacial material and include orgnic matter which occurs in nearly all samples.

12:2 A survey carried out in 2003, as part of the international DIAPLU programme (behaviour of PLUtonium during the DIAgenesis of marine sediments), at a much higher sampling resolution than that used by the BGS, indicated that the distribution of sediment types differed significantly from the BGS interpretation in the region bounded ~ 54.1 – 54.6° N, 3.5 – 4° W . This mainly concerns the pattern of deposition of muddy sediments, which were found to be far more extensive than previously thought. (REF: “Diagenetic reactivity of the plutonium in marine anoxic sediments (Cumbrian mud patch – eastern Irish Sea). Gouzy. A. Et al’. Radioprotection, Suppl. 1, vol. 40 (2005) S541-S547)

12:3 As charted/mapped the Mud Patch appears to be 10 to 15kms wide and approximately 100kms long. At its northernmost extreme it lies very close to St Bees Head, overlies the sub-sea area mapped by WCM as representing their sub-sea mining zone, and extends N.E into part of the outer extreme of the Solway Firth., and extends S.E to within a few kms of the Sellafield site.

12:4 A 2002 study by DEFRA has confirmed that the reservoir of radio nuclides held within the Irish Sea sediments, particularly those from the Cumbrian Mud Patch and the near shore zone off Sellafield, is now believed to be of greater importance as a source of longer-lived radio nuclides such as 137Cs and the transuranics/actinides (Plutonium and Americium et al’) than those from elsewhere in the sea area.

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Fig 8: Map of the Cumbrian Mud Patch ....derived from BGS: it can be seen that the great majority of the Woodhouse Colliery, proposed sub-sea mining area coincides with, and lies beneath, the Mud Patch which extends north of St Bees Head and into the defined and accepted area of the outer Solway Estuary

12:5 DEFRA reports that Vibro cores have shown that the muddy sediments of the Cumbrian Mud Patch extend to a depth of several metres. The depth profiles of gammaemitting radio nuclides fall into a small number of types. Typically, muddy samples with higher 137Cs contents, particularly those near Sellafield, are characterised by relatively low near surface 137Cs concentrations that increase with depth to a peak and then fall off towards the very base of the core. The most pronounced peaks are seen in the highest activity samples that occur inshore, from just south of the Sellafield outfall to just north of Whitehaven (i.e. several miles within the Solway Firth and in the seabed area immediately above the CWM’s designated, sub-sea mining area.)

12:6 The 2002 DEFRA study also noted that although some of the previous radiological research work in the NE Irish Sea has focused on the mud patch and concentrated on the area of greatest fine sediment content, some 15-20km offshore, the 2002 work focussed on the area of highest radionuclide contents in the surface sediments, which lies largely within 3-4km from the shore, well within the range of the WCM designated sub-sea mining zone.

12:7 The DEFRA study reported that the low 137Cs contents in the near surface sediments are consistent with observations of the decline of 137Cs levels over time from the surface offshore sediments. A similar (though smaller scale) reduction of actinide levels has also been observed. The evidence supports some loss of Cs (and actinides) from the surface sediments into the water and its wider dispersion. However it is also evident that deeper levels, below a few cms deep held increasing concentrations of all man-made nuclides reflecting the nature of both higher historical discharges and the more

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sequestered nature of the deeper sediments isolated from surface interactions with normal water currents and environmental parameters.

12:8 The study noted that there has been very little work done on the impact of storms in re-suspending fine-grained sediment and facilitating its transport within and outside the mud patch and inshore areas. During intense storms, especially when they coincide with high tides, sediment is eroded in the near shore (i.e. the zone of the sub-sea mining) region and transported out across the shelf by the storm-enhanced ebb current, or a storm-wave density current. The clear implication of the work summarised in 12:7 above is that storm disturbance is the cause of the loss of Cs and actinides from the surface sediments.

12:9 The 2002 study reports that evidence of the importance of storm activity was shown in the sediment vibro cores themselves as well as from 3-D hydrodynamic modelling and concludes that the influence of storms on the Cumbrian Mud Patch is a potentially important mechanism for the transport of contaminants into the estuaries of the NE Irish Sea (i.e. the re-mobilisation, towards the shore, of the sediments and their associated pollutants). The direction of movement of sediment can vary significantly depending on the interaction of far-field and local conditions. This may give rise to longer distance transport of contaminants, through the North Channel or southwards.

(REF: “Assessment of the relative importance of biological, physical and chemical processes on the transport and speciation of pollutants, particularly radionuclides, in the Irish Sea� CSG15.

DEFRA. 2002)

12:10 The 2002 DEFRA study has also attempted to construct radionuclide generalised inventories for the muds in the Solway Firth (i.e. from St Bees Head and areas to the north and east), but did not make a similar attempt for the marine environment south of St Bees Head. However the WCM sub-sea mining zone is so close to the entrance of the Solway Firth that the figures may be representative.

12:11 Previous inventories were based on large numbers of surface gamma measurements, collected either during hovercraft surveys or on foot. These measurements can now be linked to the deeper core profile data obtained for this study, rather than the shallow cores collected previously. In most cases, the top 10cm has lower levels of 137Cs than the complete core, or the part of the core with detectable 137Cs, where the base of the contaminated sediment is seen.

12:12 This occurs because the deeper levels were sedimented out of the water column when discharges from Sellafield and the rest of the UK licensed nuclear sites were permitted to be higher. Lower concentrations in the surface sections of the majority of Solway Firth cores are assumed to be a reflection of the lower discharges arising from increasing restrictions on the permitted concentrations allowed in liquid radioactive discharges in recent years.

12:13 Inventories have been revised in the light of the information from the new cores.

The mean depth of known contaminated sediment can be calculated from the cores. This is taken as the base of contaminated sediment, in cases where Cs-free sediment is found at depth, or the base of the core where Cs is still present. The 2002 study’s analysis of the cores from the Solway area now indicate that the known contaminated sediment depth is extended by a factor of about 3. This means that man made radioactivity in the Solway/St Bees Head region of the mud patch may extend down to 1.5 metre depths

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rather than the 50cm previously assumed (i.e. the inventories of radio nuclides in that mud are now recognised to be much greater than had been previously calculated.)

12:14 Given that the surface 137Cs content of the sediment under represents the Cs levels throughout the cores, as given by the ratio of values for the top 10cm compared to the complete core, this increases the overall estimate of the known 137Cs inventory in the tidal flat sediments by a factor of 4.5 for the Solway/St Bees region.

Thus the previously estimated inventory of 137Cs of 10.5 TBq for the top 50cm of Solway Firth sediments increases to at least 47 TBq for the greater depth. Given the relationships between 137Cs and Am and Pu isotopes, established from earlier work, the estimated inventories of these radio nuclides, in the Solway/St Bees Head area, is expected to increase to 21TBq for 241Am, 14TBq for 239,240Pu and 2TBq for 238Pu. (REF: “Assessment of the relative importance of biological, physical and chemical processes on the transport and speciation of pollutants, particularly radionuclides, in the Irish Sea” CSG15. DEFRA. 2002)

12:15 Such figures are generalised only, and are clearly region/area wide and lacking in absolute precision in respect of the WCM designated sub-sea mining area. However it is clear that both the wider area figures (para 6:4) and those for the area more closely representative of the WCM designated sub-sea mining area (para 7:15) offer the only postulates for the aggregated man made radioactivity held in the mud and sediments lying above the designated sub-sea mining area where subsidence might occur.

12:16 It is clear that there is little absolute empirical data for localised concentrations of radio nuclides at any site within the Cumbrian Mud Patch. This means that there is yet much work to be done on the more precise (small area) assessment of radioactivity concentrations in all areas of the Cumbrian Mud Patch, as highlighted by work carried out elsewhere in the n.e basin of the Irish Sea 12:17 A 1997 study investigated surface sediment samples collected from the estuary of the River Ribble. Radio- activity concentrations were measured by gamma and alphaspectrometry and activity concentrations showed significant relationships with sediment grain size with higher levels in finer-grained sediments at upstream/inshore sites, highest activity concentrations were also found at sites with fine-grained sediments.

(REF: Radiological assessment of the Ribble estuary—I. Distribution of radio nuclides in surface sediments. DJ Assinder et al’: Journal of Environmental Radioactivity, Vol 36. Issue 1 : 1997, Pages 1-19)

12:18 A follow on study on the spatial variability of both sediments and radio nuclides in near coastal sedimentary environments was carried out in 2001. This study observed that “In a previous study of the radio nuclides in the Ribble Estuary, variation in dose rates at the 100 x 12 m scale was investigated. The results indicated a range between 1 and 2 micro Sv h-1 ........ In unpublished follow up studies, the variation within a one metre square was investigated and significant variation could be seen, perhaps greater than that of the larger scale.” (REF: “Micro-Scale Variability of Contaminants in Surface Sediments: The implications for sampling”. S.M. Mudge et al’. R&D Technical Report P3-057/TR)

12:19 It is evident from the above that there are no hard and reliable calculations of the aggregated volume, or of specific concentrations, of radio nuclides in any of the regional seabed environments or marine water columns. It is equally clear that there is a consensus that large volumes of both soluble and sediment associated radio nuclides are sequestered in the regional seabed, including the sectors of the Cumbrian Mud Patch in the area of the WCM designated sub-sea mining zone. Monitoring of

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regional environmental samples chosen by the nuclear industry and government nuclear regulators makes it clear that mechanisms and pathways of biological reconcentration and bio-accumulation are present in the marine environment.

The figures given by the most recent 2002 DEFRA assessment of man-made radioactivity, for the sector of the Cumbrian Mud Patch adjacent to the WCM designated sub-sea mining zone, postulates that for 1 Am and 3 Pu nuclides there may be 37 TBq and for Cs 137 there may be 47 Tbq: ie a total (for only 5 of about 60 nuclides in total discharged to sea) of around 84,000,000,000,000 Bqs 13: Nuclear Industry understanding of mechanisms of exposure and dose delivery 13:1 There is a widely publicised and strongly supported consensus between the nuclear industry and UK nuclear regulators that the human populations who use marine and coastal environments (marine industry workers and the general public) are only exposed to marine radioactivity by a limited number of pathways. However, research by independent academics, medical researchers and citizens groups has clearly demonstrated the flaws of the pro nuclear assumptions.

13:2 Nuclear industry protocols promulgated by the IAEA protocols state that that members of the public in the vicinity of a disposal site are exposed to marine radioactivity via the following pathways: a: ingestion of seafood caught in the region of the discharges to sea (dietary dose) b: external exposure to radio nuclides deposited on the shore (contact dose) c: inadvertent ingestion of beach sediment (very limited dietary dose) d: inhalation of re-suspended “beach” sediment/sand (very limited inhalation dose) e: inhalation of “sea spray”/large droplets (very limited inhalation dose) it is clear that the various UK nuclear regulatory agencies have uncritically concurred with the IAEA position 13:3 However, these IAEA protocols offer a set of basic and extremely simplistic exposure pathway assumptions for anthropogenic marine radioactivity, based on the original simplistic hypothesis, which have been in place for many years. These pathway assumptions are very limited and have not kept pace with the growing scientific evidence from independent empirical research, which now shows them to be outdated, inadequate and incomplete.

13:4 A growing body of empirical evidence generated by research conducted by independent researchers (academics, medical teams and citizens campaigns) challenges the simplistic and outdated assumptions made by the IAEA, and notes that the basis of such assumptions has been reinforced by hypothetical modelling and that there is a significant shortfall of empirical input into the hypothetical models.

13:5 A number of independent studies have demonstrated additional exposure pathways of significance arising from multiple sea to land transfer processes. These occur as a result of a variety of mechanisms such as coastal inundation/flooding events and the production of marine aerosol micro-droplets in breaking waves in the surf zone during periods of onshore wind. Such pathways have been routinely downplayed and/or completely ignored by the IAEA protocols, the nuclear industry and the regulatory and environmental protection agencies of pro-nuclear governments.

13:6 A study published by the UK Nuclear Free Local Authorities in 2019 reported that sea to land transfer studies were initiated by the UK nuclear industry and a number of UK Governments, acting through the UKAEA which, in the late 1970’s and early 1980’s, researched the sea to land transfer of the Sellafield derived (sea discharged) alphaemitting Plutoniums (Pu) 238, 239, and 240, Americium (Am) 241 and the beta-emitting Caesium (Cs) 137, across the Cumbrian coast near Sellafield.

This work confirmed that all five radio nuclides, transferred readily from the sea to the land in sea spray and marine aerosols generated by breaking waves. The Beaufort Scale notes that waves start

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to break in Force 3 winds (8-12 mph) and the UKAEA reported that their study was conducted in up to Force 5 (19-24mph) winds. Compared to ambient seawater, Cs was enriched in spray and marine aerosols with enrichment factors [EFs] of around 2. (REF:: “NFLA Radioactive Waste Policy Briefing Number 78: Sea to Land Transfer of Man-made Radioactivity – an update”. Tim Deere-Jones. Nuclear Free Local Authorities UK.

13:7 The NFLA study noted that the UKAEA work proved that alpha emitters (Plutonium nuclides, Americium etc) were shown to have EFs, relative to filtered ambient seawater, of up to 800. It was noted that the marine aerosol micro-droplets were generated by breaking waves in both the offshore zone and at the surf line. Alpha emitters were found to be associated (by ad-sorbtion) with micro particles of sedimentary and organic material suspended in the marine water column and ejected into the atmosphere as aerosols, by bursting bubbles. These micro particles were generally in the size range of 1 to 2 microns (much smaller than beach sand), small enough to remain suspended in onshore winds for prolonged periods of time, and (wind depending) penetrate far inland and to be inhaled deep into the respiratory system. The sea to land transfer of the five radio nuclides (Cs137, 3 Pu nuclides and Am 241) was reported by the UKAEA study to be taking place along across the Cumbrian coast where any research took place, at a number of stations between Allonby (north of St Bees Head) to Walney Island, with the highest relative airborne concentrations of Plutonium 239/240 being observed at St Bees.

(REF: “Studies of Environmental radioactivity in Cumbria Part 5: The Magnitude and Mechanism of Enrichment of Sea Spray with Actinides in West Cumbria.” Eakins.J.D. et al’. UKAEA. Harwell March 1982) N.B. In the context of that report it is reasonable to assume that sea to land transfer is occurring across the entirety of the Cumbrian coast

13:8 The NFLA study also noted that once the sea to land transfer of alpha emitters with massive enrichments was confirmed, further empirical field studies were restricted and very little follow on field work on the extent of the inland penetration of spray and aerosols and human doses and exposure pathways has been completed. As a result all such assessments have subsequently been “modelled”, based on hypothetical assumptions derived from the incomplete historical data. It is also noteworthy that, of the 60 + radio nuclides known to be discharged to sea from UK nuclear sites, only the five named radio nuclides have been researched for their sea to land transfer potential.

13:9 The NFLA paper reported that onshore winds and sea to land transfer 30 year wind data from the UK’s west coast indicates that onshore winds (SSW to NNW), occur for around 5,150 hours per year. Specific individual sites along the UK’s west coast will be subject to regionally and locally variable conditions and may receive more or less hours per year of onshore wind. On this basis the NFLA Review proposed that sea discharged gamma emitting Cs 137, and the alpha emitters Pu 238, Pu 239, Pu 240 and Am 241 are transferring from the sea, to west coast terrestrial coastal zones in sea spray and marine aerosols, generated in both the offshore zone and the inshore zone, for approximately 60% of the time during an average year. (REF:: “NFLA Radioactive Waste Policy Briefing Number 78: Sea to Land Transfer of Man-made Radioactivity – an update”. Tim Deere-Jones. Nuclear Free Local Authorities UK.

14: “Independent” empirical evidence of mechanisms of exposure and dose delivery 14:1 The proposition put forward in the NFLA study is clearly supported by the empirical data. In 1988, independent empirical research by a west Wales local authority reported that Sellafield derived, sea discharged Cs had been found in pasture grass up to 10 miles inland of the Ceredigion coast (Am and Pu were not analysed for).

Clearly, this must contribute to human dietary doses via the dairy and beef food chain.

The research also indicates the probability of further dietary doses from arable and horticultural crops. (REF: Radiation Monitoring In Dyfed. 1987-1988: First Report” Dyfed County Council. Carmarthen. Wales)

14:2 Independent, empirical field research by a team of GPs in the Hebrides, has shown broadly similar, but more detailed results and demonstrated that island and coastal environments are saturated with sea discharged, Sellafield derived Caesium. The GP’s research demonstrated that islanders who ate more “local” terrestrial produce had higher

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doses of Sellafield sea-discharged Caesium 137 than those who ate “non-local” produce.

Some island residents received higher doses of Sellafield derived, sea discharged Cs, from their locally grown, terrestrial produce, than from sea foods.

The same residents received higher doses from their terrestrial produce than sea food eaters living next to some nuclear pipelines discharging liquid waste to sea. Given the available evidence of the west Wales study, it is logical to propose that the same might apply in that case. (REF: “Body concentration of Caesium 137 in patients from Western Isles of Scotland” CG Isles et al’. BMJ:

June 29: 1991)

N.B. Given that airborne radioactivity is driven at least 10 miles inland, it should be assumed that coastal populations are also exposed, on a repeated annual basis, to inhalation doses.

14:3 The UKAEA investigations, reviewed by the NFLA study, unequivocally proved that both Caesium and highly enriched concentrations of Plutonium and Americium (ad-sorbed to micro particles of sedimentary and organic material with EFs of up to 800 times) were transferring across the coastline and travelling inland.

The UKAEA study had also confirmed that marine micro-organisms (animal and plant plankton, bacteria, viruses, fungi etc) can become enriched with actinides and reported that high concentration factors (260 – 26,000) for Pu 239/240 and Am 241 had been observed in algae in the open sea. The study further noted that these micro-organisms could become concentrated at the sea surface (algal blooms/red tides etc), that subsequent suspension in high winds was possible and that marine micro-organisms were observed to be transferring from the sea to the land and that they were probably implicated in the enrichment factors observed. (REF: “Studies of Environmental

Radioactivity in Cumbria Part 5: The Magnitude and Mechanisms of Enrichment of Sea Spray with Actinides in West Cumbria” J.D. Eakins el al’. UKAEA: AERE HARWELL. March 1982.)

N.B. The clear implication of the UKAEA study is that such micro-organisms are capable

of both sea to land transfer and, subsequently, of contributing significant dose concentrations of, not only the Pu 239/240 and Am 241 recorded, but also the whole gamut of biologically available radio nuclides to human coastal zone populations.

14:4 In addition to the transfer of man-made radioactivity via sea-spray and marine aerosol production, the sea to land transfer of man-made radioactivity has been caused by coastal inundation/flooding during episodes of storm surge, tsunami type phenomena (caused by seismic events and subsidence on the seabed), spring and super tides etc.

Although such events happen annually and frequently around the UK coasts, to date they have never been investigated by UK environmental protection agencies, the nuclear industry or UK nuclear regulators for their radiological impact.

14:5 In 1990, at the north Wales coastal town of Towyn, lying on the coastline of the north east basin of the Irish Sea, a storm surge accompanied by heavy waves, caused extensive flooding of the coastal zone and deposited many hundreds of tons of marine sediment (mud and sand) into streets, tourist infrastructure, caravan and holiday parks, shops and houses.

On this occasion a Citizen’s Campaign collected 14 samples of the sediment from the flooded zone and sent it to an independent radio activity analyst and consultant for analysis for Caesium 137 and Americium 241. The analytical results confirmed that both the Am 241 and Cs 137 were present in the sediment and that the Am 241 levels in most samples exceeded the UK GDL (Generalised Derived Limit) for contamination and that 8 of the 14 exceeded the GDL by “more than ten times” N.B. If a measured environmental concentration exceeds about 10% of the GDL, the doses should be examined more closely, taking account of site-specific factors and the length of time for which the measured level is likely to be maintained.

14:6 The Consultant’s report also warned that the presence of the Am 241 “also implies the presence of the plutonium isotopes Pu 238, Pu 239, Pu 240 and Pu 241, and quite probably the GDLs for these will also be exceeded.” It also stated that “Contamination due to Americium, and probably also of plutonium isotopes..... is generally greater than limits set........for further investigations” and concluded that “the values suggest that,

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when the sediment dried out, there is a possible radiation hazard due to the inhalation of radioactive dust containing the isotopes of Americium and Plutonium.” (REF: “Radiation

Survey of Towyn: March 1990”: Edinburgh Radiation Consultants. Private contract ; Consultant deceased. Copy of Report available from Tim Deere-Jones)

14:7 However, despite the indisputable empirical proof of a number of other highly significant pathways of exposure, UK authorities prefer to adhere to the IAEA derived protocols (which are actually based on a high degree of hypothetical modelling with relatively little relevant empirical data input) and to ignore the full facts of the fate and behaviour of sea discharged radioactivity generated by independent studies at sites distant from marine discharge point sources. Concerned communities and individuals must remember that UK Governments, their regulating and environmental protection agencies and the nuclear industry have not only refused to undertake follow up research on such issues but have, over recent years, drastically reduced their radiological monitoring of marine and coastal sites not close to discharge points, principally on the grounds that it will reduce costs. (REF: “NFLA Briefing 37: FSA monitoring of Radioactivity in Food”. Tim Deere-Jones. Nuclear Free Local Authorities: 2013)

14:8 While protagonists and supporters of the nuclear industry and its activities will, and do, always insist that the IAEA protocols are “good enough” for them and that any dissent from that view is alarmist and flies in the face of the knowledge base of the nuclear industry, it is important to note that one of the major mission statements of the IAEA, enshrined in the very first sentence of ARTICLE 11 (OBJECTIVES) of it’s charter states that “The Agency shall seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world.”

14:9 It is equally important, especially in the context of the empirical evidence set out in the preceding paragraphs of Section 14, to note that the IAEA list of exposure pathways for doses of marine radioactivity to coastal zone populations and sea users has not changed, or been adjusted in light of new information, for many years and that it may thus be postulated that the organisation remains unaware of such new empirical evidence or prefers to ignore and/or to downplay it.

N.B. It is also highly relevant to also note that there is no evidence of any constraint on any sovereign nation’s government, which restricts or limits its ability to improve upon the IAEA protocol as and when it sees fit in light of emerging empirical evidence.

14:10 The empirical evidence collected by independent academics medical and citizen campaign researchers and referenced in 13 & 14 above clearly demonstrates that neither the international nuclear industry nor UK Government regulatory agencies and environmental protection agencies have an adequate understanding of the full range of the mechanisms by which anthropogenic marine radioactivity transfer from marine environments to terrestrial environments and therefore deliver doses of sea discharged radioactivity to terrestrial coastal zone individuals and communities.

However, the empirical evidence provided by such independent research clearly shows that marine radioactivity, ad-sorbed to sedimentary particles suspended in the marine water column and dissolved in the marine water column, can transfer from the sea to the land by a number of mechanisms and there deliver dietary doses of marine radioactivity (via contaminated terrestrial foodstuffs) which may be higher than those received, by some groups, from eating seafood. In addition the fact that such airborne sea to land transferred radioactivity is shown to travel at least ten miles inland means that some of that airborne radioactivity will be inhaled by coastal zone communities this delivering an inhalation doses of marine radioactivity to terrestrial populations.

Clearly, if the radioactive sediments of the Cumbrian Mud Patch should be disturbed and re-suspended following induced subsidence/seismicity caused by the WCM “mass removal”, the re-mobilisation of those radioactive sediments would increase doses from accepted pathways (seafood, contact with marine environmental media, eating beach sand etc) in addition to the very significant pathways derived from the sea to land transfer mechanisms currently ignored, down played and avoided by the nuclear industry and its supporters.

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These multiple source doses, delivered as they are, and would be, over the longer term, are highly likely to have long term health implications on not only Cumbrian coastal communities but also those further afield “downstream” of the Cumbrian Mud Patch.

15: Final Conclusion It is evident that there is a lack of data about the status of the existing historical galleries and workings of the West Cumbrian Coalfield. It is also evident that there is a lack of accurate data about the history and status of any subsidence seismicity in the coalfield.

It is noted that the BGS have concluded that the coalfield is heavily faulted and has a long history of subsidence and that it appears that there are no plans to monitor for any subsidence prior to, during the operational phase or in the post operational phase of the Woodhouse Colliery. It is noted that subsea monitoring equipment is available and could be deployed in the region in order to monitor for any subsidence effects arising as a result of the proposed Woodhouse Colliery “mass removal” extraction.

It is concluded that there is a real potential for subsidence to occur as a result of the “mass removal” and the creation of extensive sub-sea void spaces, and it is noted that such subsidence could generate earthquake and liquefaction effects which may extend onshore as far as the Sellafield/Moorside sites.

It is concluded that any seabed subsidence in the WCM designated sub-sea mining zone would generate re-suspension of Cumbrian Mud Patch heavily radioactive seabed sediments. It is concluded that such an event would generate elevated doses of man-made radioactivity to coastal zone populations and sea users along both the Cumbrian coast and at “downstream” regions further afield.

Given the potential for such a radiological effect and the delivery of increased doses of radioactivity to relevant coastal zone communities, some of which have already been identified by the authorities as Coastal Critical Groups, the Woodhouse Colliery proposal (especially in the absence of any precautionary mandatory subsidence monitoring) is strongly contra-indicated and should be abandoned >>>>>>>>>>>>>>>>>..........<<<<<<<<<<<<<<<<<<<< Tim Deere-Jones (Marine Radioactivity Research & Consultancy) June 2020

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