@daodao is right. And my point is that, once HM Treasury get involved, the axe will be near at hand. Claiming it’s “strategic” will generate first a hollow laugh, then a reflex to kill the project before it becomes a zombie, consuming cash and delivering nothing. Bear in mind their support of previous strategic projects like HS2, Nimrod and TSR2.
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Closure of Bransty Tunnel (near Whitehaven) expected until further notice
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Both you and @daodao are living in a dreamworld if you think that a bus shuttle along the coast will be seen as an adequate transport solution for this area, both practically (its too long) and politically.
I dare say even a tricky tunnel on its own might be bite sized enough for the state to manage, compared to HS2.
I didn't say anything about the quality of the answer - merely that you should beware what you wish for.
Bletchleyite
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Speculation continued in here: https://www.railforums.co.uk/thread...e-and-other-speculation-on-this-issue.290244/
Annetts key
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I have to ask this.
If the existing rock (or lack of) that the track sits on through the tunnel was really weak, the tunnel would have been closed to rail traffic long ago because either the track would have already distorted under the weight of trains or routine inspections would have detected movement of the trackbed.
So it is possible that the situation is not as bad as some are implying. I don't see any benefit in wild speculation. Until Network Rail provide more details, we won't have any facts to help us determine what future this route has.
If the existing rock (or lack of) that the track sits on through the tunnel was really weak, the tunnel would have been closed to rail traffic long ago because either the track would have already distorted under the weight of trains or routine inspections would have detected movement of the trackbed.
So it is possible that the situation is not as bad as some are implying. I don't see any benefit in wild speculation. Until Network Rail provide more details, we won't have any facts to help us determine what future this route has.
Annetts key
Established Member
Box Tunnel near Bath has a river flowing under the track within the tunnel. IIRC, I was told that the track is supported by a combination of wood beams and maybe steel beams. I've never seen what supports the track (it's hidden by the ballast), but have walked along the track over the river (well the entire tunnel actually). You can clearly hear the water rushing under you where the river is.
The question is, how good is the rock that would need to support any beams?
As I said earlier, until we have more information, we are just guessing.
It's also possible that the recent discovery is not a "new" problem, but that the "problems" have been present since the time of construction. But over time, the railway has forgotten and the records (if any) have been lost. Or it was not good to start with, but has got worse.
And now, with different engineering standards to consider, no one will be happy for it to reopen until "strengthening" work has been carried out.
HSTEd
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The problem is that you then have to hope that the ground you are supporting the beams on is more solid.
Given the number of mine workings around there, that is far from guaranteed.
And setting up a core drilling rig inside the tunnel to find out is rather challenging and extremely expensive.
They'll be able to spread the load. By their nature, mines require a certain amount of solid ground to support themselves.
yoyothehobo
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Citation Needed
IF you have ever seen victorian or older coal mines you will realise just how incorrect this statement is.
If that wasn't the case, there wouldn't be a mine, just a depression on the surface.
Anyway, this all academic as I've no doubt that the engineers at NR will come up with a solution.
yoyothehobo
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Like there is over a lot of the country, there is a heck of a lot of areal subsidence from coal mining all over the UK.
I am sure a solution will be found by whomever is doing it. My guess is that whatever is going on is complex and will take more effort than simply grouting up or putting in some girders.
zwk500
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The issue is that the mine is dissolving itself, if I've read the news articles correctly.
HSTEd
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Just because the mine stood up for a hundred years does not mean it will do so eternally.
Especially if there are old pit props that are finally disintegrating, or chain reaction rock failures are occurring.
Especially if there are old pit props that are finally disintegrating, or chain reaction rock failures are occurring.
zwk500
Veteran Member
The government is not going to take over the running of this project. It would have done so within a week or 2 of the disruption starting if so. It would have had everything thrown at it to get it reopened. See Nuneham Viaduct.
As this has not happened, it can reasonably be surmised that the disruption being caused by the tunnel is acceptable to national Government to continue for the foreseeable future, and therefore any solution proposed will need to be mindful of the resources available to it.
I still believe full and formal closure is unlikely for the much greater political cost, and that a solution will be found, but it might take a while to get one that fits within the proportionate budget.
Well quite. As I've mentioned, I would only expect Government intervention as a last resort, but if things really were to ground to a halt, Government would do well to avoid some unwelcome political narratives.
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If that is the case, it sounds as though a chunk of Whitehaven itself may be in danger.
Annetts key
Established Member
Lots of rock types (especially some sedimentary types) will gradually be affected by water causing them to dissolve. It can affect many places. But normally we just ignore what's underground until the effects are seen at the surface...
StoneRoad
Member
I saw an area on Tyneside that had been "Pillar & stall" mined - and the pillars robbed - finally opened up to the surface to extract the pillars. It was worth open-casting as quite a volume of coal had been left to hold up the roof.
Must see if I can find images ...
Something similar happened beside the M6 near Wigan. I believe that lots of coal was recovered and plenty of industrial archaeology was revealed as they went down the seams - but I didn't see any comment about what they discovered re the area of the surviving pillars!
StoneRoad
Member
I know it's anecdata, but an older [much older] member of the family I married into was a mines deputy, and - apparently - one of the things he said that he watched for was pillar robbing as doing that with insufficient props / supports was a recipe for disaster.
surely this is just Gypsum and rock salt? Sedimentary rocks will be mostly (almost exclusively?) quartz, clay minerals or calcium carbonate, none of them particularly soluble!
but the places which are vulnerable are pretty well known. Shallow chalk mines (prehistoric and recent) can pose problems, also shallow seams of gypsum - as seen in or around Ripon.
p.s. I was really trying to say that the vast majority of the UK, even the bits on sedimentary rock, is safe to build on!
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StoneRoad
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Can add the various limestones to that list - they are mostly Calcium carbonate / Calcium sulphate.
The prime example of what happens is the collapsed caves that form Cheddar Gorge ...
I thought about that, but in reality (I think) it only happens over geological time. I'm not aware of any limestone gorges which have been created by collapses in human history. Interesting question: Has there been one/when was the last?
themiller
Established Member
Near Egremont in Cumbria is a body of water called Longlands lake. One night, there was a loud ‘thump’ and in the morning the ground was seen to have slumped. It was decided and later proved that it was the result of hematite mining and the depression was left and gradually filled up with water and is now a public amenity. On Apple Maps it’s called Longlands Country Park.
At Haverigg on the site of the old ironworks there’s a lagoon which was used for disposal of slag from the furnaces. A walk around it gives a view of a structure part way across which is gently sloping from the bank into the centre. Originally this was a substantial stone wall built to impound an area of the estuary for land reclamation until the sea bed subsided due to the collapse of mineworkings under it so an outer wall was built and this is walkable today.
It goes to show that subsidence can occur at any time in the region of old mine workings and Whitehaven is riddles with them.
At Haverigg on the site of the old ironworks there’s a lagoon which was used for disposal of slag from the furnaces. A walk around it gives a view of a structure part way across which is gently sloping from the bank into the centre. Originally this was a substantial stone wall built to impound an area of the estuary for land reclamation until the sea bed subsided due to the collapse of mineworkings under it so an outer wall was built and this is walkable today.
It goes to show that subsidence can occur at any time in the region of old mine workings and Whitehaven is riddles with them.
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Annetts key
Established Member
They are not quite proper stalactites as they are formed from water running down the walls rather than being independent forms, but they have formed in Chipping Sodbury tunnel. When this area was controlled by Bristol PSB, a tell tale system was in use. The original version used a wire that ran the complete length of the tunnel, the wire runs at around shoulder height along the tunnel wall. The idea was that in the event of an emergency, a train driver could break this wire. This would then sound an alarm in the PSB and put all the signals that were on the approach to the tunnel back to red.
The system was renewed around twenty years ago. It did not take that many years for one of the "stalactites" to grow over and around the tell tale wire. The tell tale system was later replaced with a different system. And since then, when control moved to TVSC, that was not included (so is now redundant). But a piece of electrical wire will forever be embedded in stone in the tunnel...
OhNoAPacer
Member
Thought this might be of interest.
This links to a map showing known mine shafts in the Whitehaven area. James pit and an unnamed one nearby would seem to be possible candidates for workings that might cause issues for the rail tunnel. Obviously others will have a lot more expertise on such matters.
This links to a map showing known mine shafts in the Whitehaven area. James pit and an unnamed one nearby would seem to be possible candidates for workings that might cause issues for the rail tunnel. Obviously others will have a lot more expertise on such matters.
ScottGallagher
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Ironworks at Haverigg? i thought only Millom had that which closed in 68 and is now a nature reserve.
Elecman
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Haverigg and Millom are very close to each other
Pinus contorta
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The old iron ore workings ( now flooded) are at Hodbarrow. The Iron Works was in Millom. They are close to each other. The mining activities ceased shortly before the iron works closed in 1968
ScottGallagher
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I know that much , ive been going up for over 40 years , have family in both and walked all around the shores in that time, though theres not much evidence left to see ,i honestly thought the mines and the works were part of the same huge complex, I must pay more attention to the locals!
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