2. It is acknowledged by all the consultants and their advisors that this sandy beach has a very special and unique make up. The sandy bays here are the result of man’s mining activity. The sand is derived from the mining of the china clay and is a mining waste material. The mining of china clay is a hydraulic mining operation where water is directed at the kaolinised granite surface.
3. The water jet disaggregates the kaolinsed granite, putting the clay into suspension, and the sand fraction scalped away. The make up of the granite enables the sand fraction to be freed very easily so that the mioneral shape of the sand is not altered in the process. Before the era of environmental concerns, the surplus and unwanted waste materials were flushed away down the local water courses. A number of the local beaches in Cornwall are made up of various types of mining waste from a variety of sources.
4. Historically, the beach at Carlyon Bay is a very new beach. It was formed due to the Porth stream having been diverted from its natural course of flow into Par Bay in about 1850 by the construction of an adit under what is now the golf course. Thereafter the beach at Carlyon Bay was built up over a period of one hundred years from 1850 – 1950. The sand carried to the beach was coarse, angular and generally not ground up. It travelled about three miles downstream, and descended through about six hundred feet. It was made up of course quartz, mica, tourmaline, felspar and kaolin trapped in the indentation and crevices of the other minerals.
5. This helps to explain why the material found at the Carlyon Beach is unique in its make up. It is a mine waste, not a marine sand. It is evident that the various consultants did not realize the significance of the age or the source of the beach material which resulted from its unique nature. ( Reference 1 CE Everard ) The developer’s consultants used data furnished by Hydraulic Research, HR Wallingford’s and CSMA Consultants. The final Environmental Impact Assessment was produced by Wardell Armstrong International. The earlier assessment of this area, undertaken in 1989/90 by Hydraulic Research, indicated that major problems were posed here, and they stated at that time that a large amount of data would need to be collected over a long period of time on this site. These studies were never undertaken.
6. When Wallingford’s took over the project, there was very little in the way of raw data. They were forced to use numerical and computer programmes and used many assumptions, extrapolations, interpolations and data from areas that were basically unsuitable because they did not match the ground conditions at Carlyon Bay. As I have stated, these beaches are made up of china clay sand waste discharged to a river and deposited at sea via a tunnel.
7. The design of the sea defences suggested by Wallingford was based upon studies of a Californian Beach, which was made up of natural marine sand. Little attempt was made to show how the Californian beach material and environment showed any similarity to that of the Carlyon Bay beach. The status and make up of the two beaches do not show any similarities and scientifically do not compare. This is why the scientific logic falls down.
8. The marine sand beaches, used in the studies, are from long established mature beaches which have been sorted, abraided and stabilised by the workings of the sea for at least ten thousand years and probably very much longer whilst Carlyon Bay is - in geological terms – a very new beach, fed by mine waste. It is unstable, and is constantly in flux and change. Having been established for less than two hundred years, it is not in equilibrium with the sea environment.
9. The data on wave and tidal conditions was based on measurements from Falmouth, Mevagissey, Plymouth and various other locations. These areas are in very sheltered estuarine localities or places well sheltered from the severe weather conditions generated from a southerly direction. To give a true reflection of the weather and tidal conditions likely to be encountered here, a study of at least ten years would be needed. In the evolving climatic conditions, this is essential.
10. There is very sparse data available on the depth and make up of the sand on such a large and complex site. There were significant variations in the sand discharged here over a hundred-year period. Changes would have occurred in the mining methods, and there will be marked variations in the makeup of the kaolinised granite being worked.
11. There would have been times when the mine workings released clay-laden sand, which could have formed lines of weakness within the sand. In my experience, the interface between the sand and bedrock could possibly form a slip-plane. The bearing pressures within the sand could vary widely. In this development proposal, the sand must be able to withstand the weight of the sea defences and the major development to be built behind the wall. No information has been made available about the bearing-weights of the development on the landward side of the sea wall, which would be necessary prior to the validation of the design of the sea wall itself.
12. The ground water regime has been given scant study. There are very extensive mine workings to the north of this site. They are known to occur under the golf course and along Par Moor. The old drainage adits of these mine workings are very likely to be present under the beach. An old mining engine house is shown in one of the old photographs. It is also known that Par Moor is underlain by a buried valley which is over eighty feet deep. This was cut during the last ice age. The area south of the beach also contains buried valleys filled with sand, and there are a number of shelves cut into the sea floor.
13. The underlying beach rock shelf is, in places, more than eighty feet deep under the beach and that the sand resting on the shelf will be saturated. Sand is often quoted as having thirty percent voids, voids being the spaces between the grains of sand, but it is known that this very angular sand can have voids of over fifty percent. The whole design approach is flawed, because there has been no comparison of like with like. Computer and numerical modelling has been used simply because of a lack of usable data. There has been an extensive use of data from other areas suitably modified to fit into the models, but this data is not wholly applicable to this area.
14. A number of reservations were expressed by Royal Haskoning, the Borough Principal Engineer, the Halcrow Group for the Environment Agency and Doctor John White. None of these consultants have demonstrated an awareness that they were dealing with a very special material. This lack of scientific understanding underlines the problems posed by comparing two unlike materials. The attempt to place Carlyon Bay sand between a shingle and a sand asks far too much of any computer programme. To do this with any certainty, it must be shown that Carlyon bay sand is a marine material of the same nature as the sand and shingle materials being used in the model. That did not happen, and thus the findings cannot be scientifically sound logic.
15. There are many, many examples in the last few years where detailed computer models have been used to design engineering structures. Unfortunately, many of these have failed due to factors being omitted or ignored. The most noted example of structural failure in the last few years is the Team Phillips yacht. This was intensively researched using computer models, and was hailed as a world-beater. It failed on its first real test in true ocean conditions.
16. The design of the sea defence works requires nourishment to maintain the beach width and protection for the rock armour. The nourishment would require the dumping of large quantities of china clay waste sand into the sea. This material is made up of quartz, felspar, mica and tourmaline. However, there will also be a quantity of semi-heavy minerals such as arsenopyrite, chalcopyride, monazite, pyrite, sphalerite, wolframite, zenotime and zircon and of course, semi kaolised felspars. There has been no detailed study of the effects of sea water on the decomposition of these minerals and yet sea water is known to be a very aggressive medium.
17. It is likely that phosphates, sulphuric and hydrochloric acid would be released. It is known that monazite, zenotime and zircon with mica can have radio-active elements in the crystals. Due to the winnowing effect of water movement, these minerals will become concentrated over time. They are semi heavy minerals, which will tend to stay in place, whilst the larger lighter minerals such as quartz sand will be winnowed away to the east with coastal drift.
18. There has been a marked movement of sand eastwards since the beach work started. I have identified coarse Carlyon Bay sand blocking the entrance to Polkerris. What is happening is the alteration of the status quo formerly found in the Bay, creating an unpredictability. Similar problems occurred at Hall Sands when large amounts of material were removed from the seabed near the village.
19. Wallingford have claimed that the test bed results indicate there are no problems with the sea defence design but these test bed tests must be questioned because there is very little detailed information on the morphology of the Carlyon Bay area. The depths to bedrock are poorly understood, as is any variation in the make up of the sand pile. Central Cornwall is known for its concentration of sand tips. All of these tips are strictly monitored and designed to very strict limits. They must be very well drained, so that there is no water pressure build up which could cause structural failure.
20. In the granite area with its waste sand tips, there are no major buildings on any of these waste tips. These tips are constantly monitored, and water levels within them strictly controlled. These measures ensure the stability of these waste tips. The sheet piling used on the beach will interfere with the ground water flow and could lead to loss of cohesion in the lower levels of the sand.
21. The levee failure in New Orleans showed many similarities to the type of defence used at Carlyon Bay. The defences failed without overtopping or exposure to the surge water. The sheet piles failed due to poor ground conditions.
22. The wave data used at Carlyon Bay is mainly made up and synthetic, using extrapolated information from other areas. The flood and surge data from the most recent flooding on the beach was not incorporated in this study yet there were major tidal surges in 1987, 1989 and 2004 which caused extensive flooding on the beach. There is no long term data of conditions in St Austell Bay. Sources used were Falmouth, a very sheltered estuary, as was the information from Plymouth. Information from Mevagissey is again from a very sheltered area which is not subjected to fierce southerly storms. The information used from Weymouth and Portland is again from an area well protected from southerly and south westerly storms.
23. The major flaws in the whole design process can be summed up from two basic stand points. There is very scant local data to feed into any prepared model for the beaches at Carlyon Bay. Secondly, there is a lack of scientific understanding as to the theoretical basis for the models which were based on marine sand whilst the sands at Carlyon Bay are sands from discarded mine waste. No in depth studies of the behaviour of mine waste material beaches have been undertaken, especially ones that are in constant flux and are not in equilibrium with the natural environment. The attempt to place this beach material as being between shingle and sand is flawed. The Carlyon Bay sand is very angular sand made up of several minerals, and is not marine sand with its well rounded profile. The sea wall protection and nourishment has thus been subjected to a very limited and flawed study.
24. The reaction of sea water with these minerals could release a cocktail of toxins to poison the local sea water. It is known that potassium is slowly released from china clay waste since it has been used as a local fertilizer for many years. The mica and china clay content of the waste sand will have a smothering effect on the near shore sea floor. Mica and kaolin have a very large aspect ratio. This ratio compares the surface area of the mineral with its thickness. The minerals are very thin but have a very large surface area. They will slowly settle to the sea floor, blinding it, like a permanent coating of confetti. Another aspect of china clay waste which could have a serious effect on the sea environment is that it is oxygen deficient. This requires a detailed study to establish the extent to which it would denude the local sea water of oxygen, creating the possibility of toxic bloom developing over the longer term.
Notes Referring radioactivity potential in China Clay Waste Sand.
25. The extensive potential pollution of the sea environment by the addition of fresh "sand" has been highlighted. The recent worry about the radio-active content in the Blackpool Pit area raises further concerns for more detailed study. The sand from the China Clay workings are known to contain many mineral inclusions. The radio-active species include monazite, mica, thorite, illmenorutile and metamic zircon. There can be concentrations of these when the clay is recovered. The full range of radio-active radiation should be investigated and the main source areas for these minerals should also be defined. There will be a wide range of concentrations in different parts of the china clay area.
26. For example, it is known that there can be high concentrations of radon gas emanating from areas within the St Austell granite, which must be diluted to ensure the health of people in these areas. With these levels of radioactivity, which can endure for hundreds of years, no unnecessary risks should be taken when dumping china clay waste onto the line of the sea defences.
Notes Referring to Toxicity:
27. The discharge of clay waste (known locally as ‘Stent’) to the rivers by the China Clay Industry was suspended in the early 1970’s. This was at the beginning of the programme to meet the new environmental requirement for cleaning up of the local rivers and water-courses. Measures were then investigated to see if the waste could be discharged off-shore into the sea. After much planning and investigation, it was found impossible to be certain what would happen to the waste. The cumulative make-up of the waste was impossible to determine. If permission for a similar scheme, for the periodic disposal of china clay waste to the sea over a long period were to be applied for today, it would be refused and yet this development scheme (now approved in principle by the Borough Council) for the beach extension and its subsequent maintenance literally calls for the regular dumping of china clay waste into the sea.
28. The initial massive deposit of up to 200,000 tonnes of waste along the shoreline is to be followed in a continuous ‘renourishment programme’ by further regular deposits of thousands of tonnes annually, triennially or as required through tidal depletion, or when a storm has depleted the beach. This amounts to a programme of planned pollution in perpetuity.
29. This scheme still poses a large number of unanswered questions, for example :
A) What is the present chemical make up of this waste and what may it be in the waste to be used over the next 100 years or so of the programme ?
B) Have the values of those toxins known to exist in some of this waste been determined ?
C) What are the levels of iron, copper, lead, zinc, chromium, arsenic, phosphorous, chlorine and any other heavy metals or chemicals remaining in the waste ?
D) Even after the proposed washing, there will remain a percentage of mica and kaolin in the waste which must also be measured, as these will blind the sea-bed very quickly.
E) Is the dumping of such waste not an infringement of E.U. regulations, and does it not go against the bathing water directives of the E.U.?
F) Most E.U. rules and directives are changing constantly, what allowance is being made, or will need to be made, for these changes, and what is the manner in which the beach is to be "renourished" if the china clay waste is or becomes illegal ?
30. These and many other important questions (such as the known migration of this material to other parts of the coastline) must be resolved prior to the implementation of any programme of waste discharge on such a large scale.
Notes Referring to Subsidence resulting from Mine Workings:
31. I have over the years inspected over 500 mine shafts and other workings, all over Cornwall. Whilst the failure of these structures can cause a local nuisance, I have not come across any that have caused major disruption apart from the Callington subsidence, which was exacerbated by its occurring in made up ground. The mineralization in the South West Ore fields is in narrow vertical or near vertical veins. These do not cause the widespread subsidence which is associated with coal mining activities. However, the possibility of mine workings being still present under the beach highlights a further potential danger to the site.
32. It is known from past experience that the mine shafts on the golf course and at the back of the Wyevale Garden Centre were "popped open" by changes in water pressure in the old mine workings, and it cannot be assumed that this will not happen to the workings under the beach. The mine workings on Par Moor and under the golf course are very extensive and reach to (and under) the beach. These workings are all filled with fresh water and must drain to the beach. As stated earlier, no study has been undertaken of this ground water flow. If there was major flooding from Par Moor, then a siphon effect would occur. If the flooding lasted for any length of time, the foundations of the beach would then be destabilized.
Notes Referring to Levee Failures in Katrina Floods, August 2005:
33. The levee which was designed to protect New Orleans shows many similarities to the proposed sea defence at Carlyon Bay and the levee defences failed without overtopping or exposure to surge water. The main culprits of the failure were shallow sheet piles, bad ground conditions and inconsistent construction materials. The sea wall defence, sheet piling and sand foundation at Carlyon Bay are likely to be overtopped on a regular basis. The frequency will be dependent on the storm patterns. Further, these defences will be subjected to surge water invasion twice a day with the tides. This must destabilise the foundation sands, resulting in an inherent fragility in the whole design of these defences.
34. Although there has been a lot of desk-work and computing of numerical analysis on the overall design, the flaws and negative aspects of the proposed development remain unanswered. This is an experimental development, there being no detailed studies of mine waste beaches in the technical literature.
35. The use of a marine beach sand to compare with a new mine waste beach is scientifically flawed. The renowned consultants who tried to assess the validity of the sea defence design did not fully account for the unique nature of the Carlyon Bay beach sands.
36. The lack of basic and long term local data forced a reliance upon computer modelling data, modified from outside sources, which thus questions the validity of the data produced. Reliance upon computer-generated designs has often led to spectacular failure, typically the Team Phillips yacht.
37. The sand at Carlyon Bay is acknowledged to be highly mobile and ever changing, and the consequences of adding further large quantities of mine waste sand is equally highly unpredictable. The study of the disposal of mine waste in 1972 into St Austell Bay led to the conclusion that it was impossible to predict what would happen to this material on the sea floor.
38. An adequate statistical sample of weather, wind, wave, flood and tidal flows would need a study lasting at least ten years. There are a number of shortcomings in the assessment of the sea defence design which provide a potential for disaster, for both life and property.
ALAN FRANCIS, BSc.Hons. September 2006