When we capped our shaft (to save around £20,000!) at approximate cost of £3000, we had to excavate to solid bedrock - around 5 metres (the shaft had been partially filled) and include a vent to allow for any air movement such as caoused by old workings collapsing. We then put 21 cubic metres of C40 (acid resisting) concrete in the plug. Talk about overkill. The plug is more solid than the surrounding ground.

It is the size of the excavation that wrecks any remaining archaeology.
wheal

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I've scanned the document re the treatment of the Park House shafts. http://www.aditnow.co.uk/documents/Park-House-Coal-Mine/Park-House-Shaft-Abandonment.PDF 
I've got the drawings to go with it but they're too big to scan - I'll try & photo them later.
Hope it's of interest.

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Excellent, I like the prices at the end! Thanks 🙂

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The latest time I did some research on the subject of shaft capping I was interestingly enlightened of a new technique by Simon Hughes. The use of large quantities of polyurethane expanding foam were tested as a shaft capping method in the USA and has now been used at a few locations around the UK with good success. I can remember all the details now but from what I can remember one 45 gallon drum of liquid form would expand to something like 10 its volume ore moor when activated. I have got all the info on a hard drive somewhere I will dig it out and post it up

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In the first half of the last century the NCB in Northumberland seemed to cap their shafts with a single layer of old sleepers laid on a steel frame. As kids we used to lie on them searching for a gap big enough to drop small rocks down. The 'best' we found was one in which it took thirteen seconds to hit anything and even then it kept crashing for several more. Happy days - and we survived.
IanH

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The latest time I did some research on the subject of shaft capping I was interestingly enlightened of a new technique by Simon Hughes. The use of large quantities of polyurethane expanding foam were tested as a shaft capping method in the USA and has now been used at a few locations around the UK with good success. I can remember all the details now but from what I can remember one 45 gallon drum of liquid form would expand to something like 10 its volume ore moor when activated. I have got all the info on a hard drive somewhere I will dig it out and post it up

Many years ago I came across a gang filling one of the Sapperton Rail Tunnel shafts.
Not sure what they had done at the bottom but the main filling material was very large polystyrene blocks, probably 4 by 4 by 10 feet section, the smallish gap at the circumference was being cement grouted
This technique was designed to considerably reduce the weight of the infill. Forgot to ask about any surface cap.

Came across a company called Benefil (www.benefil.co.uk) whilst looking at mine details yesterday. They are using polyurethane or similar to cap/fill shafts and mine workings.
They show piccies of shafts capped at an ASDA carpark at Tonypandy.

Interesting solution.
Wheal

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That’s interesting about the foam blocks I bet it saves a lot of time and like you say Morlock it has a massive weight reduction on the surrounding ground especially with a deep shaft making the ground a lot more stable

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It would appear there has been recent work on the many construction shafts at Sapperton.

http://www.networkrailmediacentre.co.uk/content/detail.aspx?ReleaseID=4735&NewsAreaID=2&SearchCategoryID=7 

There are some ridicules regulations around shaft capping. when my neighbour wanted to cap the engine shaft of 200 feet in his garden he was told by the environment agency that they would only allow the use of washed scalping so not to pollute the site which would make it to dam expensive. this strikes me as mad because the surrounding ground is contaminated enough by the dumps. in the mean time the locales will fill it with old house hold crap. they should have let us go with the old Transit van option ::)

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I can take you to a few local shafts here that were open until about 10 years ago and got filled with demolition rubble... when asked the owner said... "Bl**dy fly tippers eh" :lol:

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A lot depends on the money available. Around 1980, we had a contract to cap shafts on Bonsall Moor in Derbyshire. We capped hundreds of them - 72 in one field! However they were only small and done with concrete railway sleepers. Some of the bigger ones had Bison beams instead. None of these caps would survive a collapsed lining but overall the moor is a safer place.
In the early 90's, we did the Snailbeach shafts. They were different again being large, deep and well trampled by tourists. For that reason money was available and they got the full treatment.
Georges shaft for instance, was filled with tip tailings up to the rockhead. At that point we drilled dowel holes and cast a 3metre thick plug. Then filled again with selected tailings up to near the surface and another concrete slab that forms the bottom of the dummy shaft seen now about 2metres down. I would guess that that one shaft cost more than half of Bonsall Moor to treat.

I can take you to a few local shafts here that were open until about 10 years ago and got filled with demolition rubble... when asked the owner said... "Bl**dy fly tippers eh" :lol:

:lol: i like his stile the old way was much more fun. At stafordshirechina can you remember how much the capping at snailbeach cost back then

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the old Transit van option ::)

Predecessor of the 'plug the shaft with a motor vehicle' technique was dropping a tree in trunk first, sufficiently bushy to jam at the shaft collar. Probably didn't stay in place as long as a motor vehicle.

Have abseiled through vehicles at Darren and at Glog Fawr, both in Ceredigion. They are a disconcerting sight from beneath...

Aaaaaah the Austin A7 option as described to me by a Cornish farmer! :lol:

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Mk.1 Cortina at one or both of Darren and Glog Fach as I recall. Abseil route went through a front wheel arch; rebeyaed off something mechanical to avoid rub points. Car didn't seem to be actually held up by anything when viewed from underneath... but it hadn't moved 15 years later when I last looked at the shaft.

Mk.1 Cortina at one or both of Darren and Glog Fach as I recall. Abseil route went through a front wheel arch; rebeyaed off something mechanical to avoid rub points. Car didn't seem to be actually held up by anything when viewed from underneath... but it hadn't moved 15 years later when I last looked at the shaft.

my god the Mk.1 Cortina method would be a dam expensive way of capping theys days.could be worth another abseil at Darren just to ebay the parts 😉 fair play to you mate i wouldnt fancy that as much as i would like to go in for a look.

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Sorry James, I don't have any figures now but I remember we reckoned that over the years leading up to and treatment of Snailbeach, our share was around the 1/4 million mark. That would be peanuts though compared to how much the consultants and two main contractors got.
Talking of trees - that was what was forming the blockage in Georges shaft.

worth every penny the site is a credit to you chaps

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When you say you saved £20k for capping your shaft, was that an official contractor quote? I ask because we're buying a small holding that has a back-filled shaft that has been recommended by the mining survey is officially capped. We wanted to know roughly what these things cost as we might have to renegotiate the cost of the property. Was the £3k you payed for capping it DIY style? Many thanks. Phil