Masson Cavern Roof Cracks

[pwhole]

We've had a report come in to the Cave Registry email of a large crack in the roof in Masson Cavern - sounds like it's around Crichman Chamber area, and apparently you have to go under the cracked section. 1.5m diameter chunk of roof and about to fall, was the report. Is there anyone local (or more local than most of DCA!) able to take a look in the next few days?

 

[speleokitty3]

There have been lots of big cracks in the roof between the quarry entrance and Chrichman since I first went in there in the 1980's. It would be interesting to see if anything has changed but I'm working away this week.

 

[Flotsam]

They'll last a lifetime

 

[pwhole]

The crack has been narrowed down to the section of roof on the slope as you enter Crichman Chamber from the quarry entrance, where the old founder shaft brings water in.

 

[speleokitty3]

The crack has been narrowed down to the section of roof on the slope as you enter Crichman Chamber from the quarry entrance, where the old founder shaft brings water in.

Sounds familiar.

I don't think I ever noticed this on the way in but it's quite visible when you turn around or head out.

 

[pwhole]

From the poster of the problem, showing where it is - thanks to Smiffy:

 

[Tangent_tracker]

Is it worth putting a tell over the crack to see if there is any change?

 

[pwhole]

Our problem at DCA is that no-one can get over there at the moment, and possibly not till after Xmas, so we're hoping someone local can take a look and make a call on the likelihood of further movement - which would only be an educated guess I'm sure! But yes, any way of monitoring it would be welcome - it certainly gets plenty of visits.

 

[zomjon]

I’ll pop in with Ric in next couple of days if any use

 

[pwhole]

I was hoping one of you might write that - very much so! Thanks

 

[Tangent_tracker]

We are heading their for our club get-together on Sunday. Could put a little wedge in for now if you wanted? If you are at the TSG phil I'd be happy to pick you up on the way so you could join us? Mince pies and Mulled wine!

 

[pwhole]

Hahah - possibly. I'll let you know

 

[Tangent_tracker]

Got a picture of the crack...

 

[Tangent_tracker]

Another piece that has previously peeled off. Might be an idea if folks go to the right of this part for now.

 

[pwhole]

Sorry for the delay - was out all yesterday. I must say it's not that long since I was in there and I don't remember that! Hmm...given there's about 20m of limestone above that I'm not sure if an Acro prop would make much difference

 

[tomferry]

What about building a stone cog under this. I may be in the area soon have never been in this place before but is the area of decay easy to find ?

 

[pwhole]

Yes, it's just a few metres beyond the entrance, as you enter the first large chamber. A friend took their parents and young brother in there yesterday and didn't report any issues, so it may not be so bad. Though realistically, there is 20m of rock above this before the surface, so there's a lot to drop potentially. Despite this, if you've never been it's well worth a visit.

 

[al]

What about building a stone cog under this. I may be in the area soon have never been in this place before but is the area of decay easy to find ?

I remember Owd Git doing something similar in Knotlow when the annual mines inspection highlighted a drooping roof, and that has certainly stood the test of time. Maybe worth asking him to take a look at this?

 

[pwhole]

It could be viable, as the 'floor' there is certainly solid rock, though it is on a slope of about 30°, so would need some chocking or maybe some long retaining bolts drilling in. Funnily enough, I have some 35mm stainless rebar pieces, in about 500mm length - got mentioned in the recent Spit removal thread. A couple of those resined into the floor would provide a good foundation for building up from - I've seen plenty of miners packwalls supported like this at the base - there's some in Middle Engine and also in the old lead workings in Middleton Mine.

 

[AR]

I remember Owd Git doing something similar in Knotlow when the annual mines inspection highlighted a drooping roof, and that has certainly stood the test of time. Maybe worth asking him to take a look at this?

IIRC that was a packwall on a steeply descending section that we rebuilt and mortared to make sure it stayed in place, rather than specifically a roof support. That aside, I agree it's definitely worth seeing what we can do in terms of packwall or cog to make sure this entrance to Masson stays open. Suggest you keep the stainless rebar for when we really need it though Phil, regular rebar supports should outlast us given how well the sites you mention have lasted on old drills!