I am hoping that someone has some helpful advice regarding the installation of a shaft using lightweight materials. I am putting together a project plan for the opening up of a site, by excavating a pit in loose material down to known mine-workings at a quite shallow depth - 5m approximately. Because the work will be best done quickly and in one go, and the location is only accessible along a reasonably level footpath 1 km long, and with a short but steep slope at the end, I need to think what material to make the shaft with. Concrete rings are going to be a real pain, so I wondered about this stuff called twin wall pipe, or bolted corrugated steel plate. Does anybody have any experience of using this sort of material (especially the plastic twin wall pipe) - any thoughts on its weight, whether it can be cut into manageable lengths and then fitted together again, or any other suitable lightweight material that can be assembled by hand and more important capable of being carried the distance involved from our nearest road delivery spot.

Thanks very much! 🙂

45 gallon oil drums with ends cut out before transport, they roll quite nicely. 6 would line 5 metres.

I am sure Roy Fellows will comment from his first hand experience.
I know that plastic pipe has been used in Cwmystwyth.

Ah yes, Morlock, we've done this before - the issue is the shaft needs to be permanent! And it would be installed under the supervision of the National Trust so needs to look the part really. When we've used drums in the past they have deformed, moved out of position, and rusted away. Plus, the diameter is an issue - the one shaft we still use with drums in it is really too small. But thanks for the idea.

I am sure Roy Fellows will comment from his first hand experience.
I know that plastic pipe has been used in Cwmystwyth.

The pipe was put in by Aberystwyth Caving Club, as I understand it, long before the mines belonged to CMT.

I have used 5mm wire, steel galvanised mesh to good effect at Talybont. It occurs that a shaft lining could be constructed from this supported by a frame of galvanised steel angle, the whole thing bolting together.

My source of the mesh was Cambers County Centre on way up to Wales, convenient, 8ft X 2.75 ft at £12 a pop.

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Fiber glass, three panels per section, bolt internally, use bolts/holes for ladderway platforms etc, maybe not the cheapest but might do?

Lozz.

Ah, a posh job.;D What sort of diameter would be considered adequate? Would square construction be considered?

Edit: This stuff any good?

http://tubosider.co.uk/products/bolted-structures/bolted-plate-structures/ 

That sounds interesting Roy - the ground where we want to build this is not clay, but behaves more or less like clay, and is likely to be subject to a lot of water percolation. Do you think this idea would work? I would be concerned about material being washed through. I suppose it could be lined with some high gauge lining material. I liked the idea of the twin wall pipe as it can be cut easily and could be installed quickly. But not having been involved in anything using it, don't really know if it is suitable, or whether if cut into sections it becomes a problem.

The twinwall pipe, while it can get quite expensive for the size you'd want (600mm, I assume), they are incredibly strong, regularly used in quarries.

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Yes it's a posh job :)

Square would be fine provided it was strong enough for the long term. The issue about time is that I would like to have the job started and finished in one long weekend. It's Open Access land (oh really) and we can't really afford to have the place unattended for any length of time. So, dug out, installed, and backfilled. If the shaft can be put down in one piece, or at least the lower half, we might be able to avoid shuttering the pit - as nobody would need to go down into it. This is a small digger job, in order to get it done quickly.

The twinwall pipe, while it can get quite expensive for the size you'd want (600mm, I assume), they are incredibly strong, regularly used in quarries.

I am thinking 1000mm minimum, so even more expensive and heavy. That's why I was wondering about cutting into sections before moving to site, but then we have to fix it all together again. Gaffer tape doesn't really cut it!

Edit: This stuff any good?

http://tubosider.co.uk/products/bolted-structures/bolted-plate-structures/ 

Yes - one of the sites I kept coming across today while searching. definitely an option - quite fiddly though, what with all the bolts. This is what we used back in 1988 on another entrance - all the bits were rescued from a nearby dump, and all the bolts were "rescued" from someone's workplace! Definitely an option, though.

Twinwall is great but very expensive. You will probably need 900mm for a shaft, anything smaller will be a nightmare to climb (try bending your legs in a 600mm or even 750mm pipe).

I know access is an issue but if it is at all possible I would go for concrete rings - great long term option.

Scaff with Armco lagging boards is a reasonable (and portable) option.

Stay away from oil drums which will rot as will timber.

What a fantastic response in less than an hour! :thumbsup:

Anyone else, feel free to throw in your 2p's worth :)

If the project "goes", and it's done in time, it may appear in the NAMHO 2017 field trips, but I don't want to tempt fate.

We managed to do a very similar sounding job over just one weekend with a length of 900mm pipe with rungs bolted inside

It rolled there no trouble at all, admittedly it was slightly downhill and over heather.

[photo]104046[/photo]

Two bits like that would do the job - it would have to be dragged lengthways though. The footpath runs through a wood. Maybe we make up a sled, and get a group of members to play Egyptian slaves for a day.

A pair of trailer axles would be ideal. Or even a quad with a trailer, if you've got (or could get) permission to take it close in.

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I'll add my voice to those recommending twinwall as a robust and long-lasting material- if you've got the budget, then get it. Sections can be bolted together if you can't do the whole thing with a single section, Pwhole can tell you more about what's involved as that's how the shaft at Longcliffe Mine is currently being fettled though he did have the assistance of the NT and a helicopter there! You can also drill parallel holes and fit rebar rungs in the side if you wish!

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For pulling stuff:

I bought one of these a while back for pulling 20 ft spruce butts through the woods, never looked back, great bit of kit, lightweight and reliable to date:

http://www.portablewinch.com/en/products/PCW5000.html 

Lozz.

Mesh could be backed with pond liner to stop water and mud. This stuffs dirt cheap from garden centres. This option highly portable and light.

The other best sounding to me is the large diameter plastic pipe possibly fitted with rungs as Chris describes.

I suspect that maybe you are lacking in resources such as helicopters and on a budget as well.

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