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Mar 23 2017

Pinner Wood School site to close at end of school day after underground chalk mine discovery

The site of Pinner Wood School is closing at the end of the school day today, Thursday 23 March, after a joint decision by Harrow Council, the governors and the leadership team of Pinner Wood School.

The reason for the closure is that geotechnical surveys have this week reported an unacceptable risk that the ground beneath the school buildings and playgrounds could become unstable and unsafe, due to the condition of very recently discovered chalk mine tunnels below.

Laser imaging of these previously uncharted and unknown tunnels reveal that they stretch beneath the school buildings and that the mine roofs have collapsed in certain places. These partially collapsed tunnels are likely to open up new surface holes under or near the school at some point in the future. This could put staff and children at risk, prompting today’s decision.

Cllr Sachin Shah, Leader of Harrow Council said:

“With the evidence we have discovered in the past few days, we are certain that this is the right decision. We would like to stress that the imminent risk to the school buildings is believed to be small. However, the Council would never ask or permit any school to operate when there is a known risk, however small, to the safety of the site or the staff and children within it.”

Deb Spruce, Head Teacher of Pinner Wood School, said:

“This is a huge and sudden shock to all of us. We absolutely need to leave this site until it is made safe. Our school is blessed with exceptional staff and governors and a wonderful parent group. I’m certain we will all rise to this challenge and show that our Outstanding school is united by much more than just our buildings.”

The surveys were conducted by Peter Brett Associates and partner Clive Edmonds – Britain’s leading geological engineering expert on chalk mines.

Dr Edmonds said:

“It is likely that the mines date from at least the early 1800s. As is common for chalk mines of this age there are no mine abandonment plans and the mine workings are in a state of breakdown, as confirmed by the laser survey, posing a hazard to surface stability. Our experienced team are purpose-designing suitable investigations to continue to map the workings in order to identify the extent of mining below the school and determine possible remedial options”.

Pupils will not return to the site until further notice. Classes will relocate to other educational settings in Harrow in time for pupils’ schooling to resume at the start of the Summer Term.

If you are concerned or have any questions please email pinnerwoodclosure@harrow.gov.uk

Meeting held for parents only

If you are a parent of a child who attends Pinner Wood School, meetings are being held tonight and tomorrow for you to find out more:

Today, Thursday 23 March, 6pm-7.30pm at West Lodge School Hall, Pinner
Today, Thursday 23 March, 8pm-9.30pm at West Lodge School Hall, Pinner
Tomorrow, Friday 24 March, 5pm-6.30pm at West Lodge School Hall, Pinner

If you are a local resident and would like to know more about this closure a meeting is being held on Tuesday 28 March 7pm at West Lodge School

Background information about the closure

During the summer holidays of 2015, a hole unexpectedly opened up in the tarmac of the staff car park at Pinner Wood School. The hole was roughly 3 metres wide and 1 metre deep.

The Council and school made the area safe and commissioned specialist geotechnical engineers, structural engineers, environmental engineers, surveyors, geophysicists and health and safety professionals to analyse the causes of the hole. They determined that the hole was situated on top of an old, disused shaft. The material used historically to backfill that shaft, they concluded, had only been loosely compacted and had subsided – creating a hole.

In the light of that discovery, we undertook to continue our investigations to make certain of the condition of the ground under and all around Pinner Wood School.

Over the past 21 months, extensive studies including probing and drilling had given no reason to believe there is any risk to the stability or safety of the school’s buildings or the site.

Our latest surveys, however, deploying the most modern laser-imaging techniques and deployed from targeted boreholes, have in recent days revealed previously unknown and uncharted chalk mines beneath the school estate, located roughly 20 metres below the surface. Some of these mine tunnels stretch directly underneath the school’s main buildings.

Furthermore, our latest surveys indicate that at least two of the tunnels underneath the school have partial roof collapses. There is also evidence that spoil (largely made up of clay and sand) has fallen from above, into the voids below. It is not known when these collapses occurred.

The professional advice provided to us is that these roof collapses are likely to migrate through the ground and open up new surface holes under or near the school at some point in the future. This could put staff and children at risk or even compromise the structure of the school building.

Furthermore, our work, though extensive, is not exhaustive. It now appears likely from the information we have that there may be further as-yet-undiscovered tunnels, collapses and shafts in other parts of the school estate.

As a result of the professional advice provided to us, the joint view of the Council and the school is that closure of the site is prudent, reasonable and proportionate.

More extensive testing of the ground throughout the site is now essential, to assess the site’s condition and safety. Such a survey is an extremely intrusive process involving rigs, drills and probes and is likely to take months, once the site is vacated.

Our hope and expectation is that, following that comprehensive survey, we will be able to stabilise the ground and return the site to a safe condition – probably by pumping a quantity of material underground to fill the mines themselves. The school would then, subject to a full structural assessment, be able to return to its current site and buildings.

It may, however, be the case that it is not economically feasible to restore the ground and that the school may never reopen in its current form on its current site.

All our investigations have been limited to the school site and although the full extent of the workings are yet to be determined, currently we know of no reason to suggest that the tunnels we have discovered to date stretch under neighbouring properties.

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26 comments

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  1. Sunny

    So Harrow Council knew of this issue over 18 months ago and have given parents and children one day’s notice. Well done to Sachin Shah and the rest of his cronies at Harrow Council for another well managed situation.

    1. Someonewhocares

      Yes, Sunny, because as we all know Shah etc were responsible for starting the chalk mines in the 14th. century, building the school where it is, the changes in water table/erosion worsening collapse and the *latest* geological surveys and professional recommendations related to this?

      – Did you actually read the whole article or just a few lines? If they had ignored the NEW data and then still kept the school open would that be more OK with you?

      – “Damned if you do, damned if you don’t” maybe?

      1. p.day

        Quite right any chance they get to rubbish their opponents via this site they will . well said SOMEONEWHOCARES

  2. Ilikefilmme (@vespa2222)

    No it was deffo Cllr Shah in 6 BC he & his pet Brontosaurus dug it to supply chalk to his hop scotch racket,later he kept Lord Lucan there to feed shergar

    1. Someonewhocares

      Really? I thought so-called ‘legal highs’ were banned now.

  3. Concerned Harrovian

    Sachin Shah probably used the chalk to draw on the cave walls to work out how much Council tax should be paid on a cave in band D.

  4. Peter Day

    Very interesting and of course instead of sending sensible information out this site has to send out a the normal unhelpful message to us all about where the children are going to be put, and if you live in Wealdstone they have made it sound like HARLEM in the U.S and for anyone that does not live there will now avoid it which will not help the shopkeepers in there. Of course the Tory’s have very, very short memories conveniently forgetting their old friend Mrs P who moved council tenants out of the so called posh part of Kensington into asbestos ridden houses away from their posh friends . Then she pushed off out of the country, and years later she was taken to court and only managed to pay a fraction of what she owed.

    1. Wealdstone Warrior

      I hardly think this article will bring down the reputation of Wealdstone. Wealdstone has been in decline the last few years due to murders, stabbings, shootings, drug dealers, overcrowded homes, mattress’s, fly tipping & drinking on the street. As for Harrow Town centre, I hardly recognise the place now and I avoid going there due to the overcrowding on the streets and the bus’s, pickpocketing & lack of decent shops.

  5. IAN LIMBREY

    Evidence for the existence of this chalk mine under Pinner Wood School can be found on the ‘Greater London Industrial Archaeology Society’ (GLIAS) website and hence Harrow Council would be aware of it!

    The website states the following:

    Name of chalk mine – ‘Pinner Common Chalk Mine’

    Address – ‘Under Pinner Wood School bounded by Albury Drive, Pinner Hill and Latimer Gardens’

  6. Wealdstone Warrior

    So Harrow Council knew of the issues in 2015, but chose to patch it up in the hope that it would go away. So may questions remain unanswered and need further investigation. I find it very hard to believe they did not know how many tunnels there are. Newly discovered tunnels, more like a cover up. These tunnels should have been filled in a long time ago before they built the school. This is a disaster in the making, so many what ifs.

    1. Someonewhocares

      Instead of immediately launching off into conspiracy mode WW take a quick tour instead:

      http://www.alpertonhistory.info/pinner-chalk-mine/

      And, in case you missed (or simply did not read) the main point, the school was closed because of the *recently increasing* number of ‘what ifs’.

      1. Wealdstone Warrior

        I have a mental picture of you Someonewhocares hunched over your computer like a spider waiting to pounce, especially on my posts. Yes I have read this article published in 2013, where it notes sand has leaked into the mines from where there has been a collapse. It also notes blocked off mines where this person was unable to explore indicating more mine tunnels. Interestingly it notes there are tunnels under Waxwell Lane Car park, same place Harrow Council has closed for building new flats. If I was buying a property in Pinner, I would have the underneath investigated and surveyed first. I am wondering if these tunnels, that are collapsing will affect homeowners building insurance? Polly Parrot has a lot of questions to answer. Lets see if he can blames this one on Tory cuts.

        1. Someonewhocares

          Well surely the real ‘pouncer’ here is you, PollyWW. Virtually EVERY time there is an issue in LBH you seem to want to blame Sachin Shah. This really does NOT strengthen your case, it weakens it – and makes it all far too personal.

          Here, as already mentioned, the Council and School Board have done the correct thing in difficult and unusual circumstances.’Fill it all in’ you say? Well I am not a geologist/concrete expert either but I would conservatively estimate that to fill all of the extensive voids immediately adjacent to the school and nearby houses could easily cost over $50M.

          Of course you did not actually go on the ‘Chalk Mines’ tour above on the link I provided. I mean, ‘why bother with the Historical Facts’? Also as stated the Mines were closed for H&SE reasons thus making it inaccessible too. (BTW, and before you start again, Shah is not on the H&SE ‘Cover Up’ Committee..)

          Finally some more information for you to ignore and yet then still somehow comment on:

          http://www.glias.org.uk/database/boroughs/borough_0016.htm

          Scroll down to Pinner….. if you read this far

      2. IAN LIMBREY

        The chalk mine tour stated above is a completely different chalk mine to the one under the school (Pinner Coomon Chalk Mine’)! Pinner Chalk Mine is located near Dingles Court (uxbridge Road) and stretches under Montesole to the southern boundary of Norman Cresent!

        1. Someonewhocares

          Yes, I realised that Ian; The ‘tour’ was so folks could see just what it looks like underground from c.20 years ago, and that over a period of 34 years it had remained relatively stable too.

          -According to GLIAS the ‘Pinner Common Chalk Mine’ site actually has an ‘unknown’ status, but which you did not mention above. GLIAS also refers to the Montesole Allotments as yet *another* mine site too. Again these workings are clearly more extensive than anyone previously thought and may/may not be interlinked.

          -The main point though is that you seemed to imply that the Council were saying they were unaware of all these 19th, Century workings. This is incorrect and as far as I can see they have deployed a group of professional specialists to asses the risks.

          -So, other than apparently criticising the Council’s actions and also misquoting the GLIAS data what was *your own solution* here then ?

          1. IAN LIMBREY

            They were ‘unaware’ of this mine as they told me on Friday morning face to face and obviously aware of others. This mine would be in their records!

  7. Wealdstone Warrior

    Someonewhocares – You may need to read the article by your beloved Polly Parrot, he quotes,

    “Our latest surveys, however, deploying the most modern laser-imaging techniques and deployed from targeted boreholes, have in recent days revealed previously unknown and uncharted chalk mines beneath the school estate, located roughly 20 metres below the surface. Some of these mine tunnels stretch directly underneath the school’s main buildings.”

    Why were these tunnels previously unknown, apparently?

    Sand has been pouring through the tunnels for a number of years, as evident on websites published by those who have toured the tunnels. There are so many statements to this extent of this evidence, that the council cannot erase this information.

    1. Someonewhocares

      Ah, I see your problem now IAN/PollyWW (other than not actually reading all the text, including your own):

      They are (obviously) saying that they knew of the MINES but not of all their TUNNELS.

      Again using 3D-scanning laser techniques to survey RECENTLY they have a much better topological map of these workings than with previous equipment.

      It would also help if you stop behaving/reacting as though this NEW information was obtained and ignored and then there was an ACTUAL disaster!

  8. Wealdstone Warrior

    Mines, tunnels = same thing, they are in denial. Someone somewhere will be able to produce the evidence that the Council was in full possession of the facts and choose to ignore and cover up the problem. This is what happens when you take shortcuts. If they had spent the money in 2015 rectifying the issue, instead of patching up a hole, then they would not be held to account now. Transparency is required, this does not just affect the school but peoples homes and business’s.

    1. Someonewhocares

      No, PollyWW, they are NOT in denial, you are about the Council actually doing the right thing.

      Mines and tunnels are NOT the same thing either, and your continued insistence on a conspiracy is frankly starting to sound even more ridiculous now, and indeed a huge hole is appearing in your rationale!

      Presumably then a hole appeared in PWS carpark and none of the pupils and teachers noticed as the Council sneaked along at night and ‘covered it up’. Oh dear – if only they had spent £50M filling all the TUNNELS with concrete and saving the school then, everything would be fine (but I am quite sure you would STILL have found something to complain about).

      Instead of whining on here why not ask Peter Brett for more information – or go the the West Lodge meeting tomorrow and spout all your strange theories there?

  9. Wealdstone Warrior

    Well we will see what happens and what comes out in the coming weeks, as this is national news now. Calm down Someonewhocares, you are so easily wound up, maybe you should find a nice quiet chalk tunnel to go and meditate.

    1. Someonewhocares

      Well WW it is really quite easy to be ‘wound up’ by misinformed alarmist and conspiratorial idiots who don’t respond to your reasonable questions and don’t actually read what you/others write so you have to keep repeating the FACTS: Unless you are doing this deliberately of course…..

      1. peter day

        I would not allow anyone who cannot give us there real name and has to use a false name like yours to put anything on this site, some people will never grow up.

        1. Someonewhocares

          That’s an interesting comment Peter Day – If that really is *your* real name!
          (Also interesting that your first comment in this thread was complimentary..)

          Personally I am more concerned about the fact-ignoring alarmist nonsense
          that some write on here!

  10. Wealdstone Warrior

    Known sites of chalk mines in Pinner listed on this website, including Pinner Common Chalk mine http://www.glias.org.uk/database/boroughs/borough_0016.htm

    Pinner Common Chalk Mine

    Address : Below Pinner Wood Schools, bounded by Pinner Hill Road, Albury Drive, and Latimer Gardens, Pinner

    Site Status : unknown

    1. Someonewhocares

      – which is the link I posted up at 12.54 yesterday which proves either you don’t read what has been written or, as I now suspect, you *are* simply choosing to be annoying.

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