D
diggerdog adam
Guest
:idea: Id like to hear your thoughts on how to bolt a 200ft+ mines shaft Its a mixture shale ! and blocks ok stone walled like bricks
SamT
Moderator
Hmm - I'd do some research - learn about the geology - Are the bricks cemented or is it ginging, what rock lies behind them - more shale?.
Do you need to bolt it - or is it a plumb shaft that can be dropped from a rope hung down the middle off a suitable anchor (scaff?).
If needs be - you can get industrial on its ass. Generators - Air drills - industrial fixings.
Do you need to bolt it - or is it a plumb shaft that can be dropped from a rope hung down the middle off a suitable anchor (scaff?).
If needs be - you can get industrial on its ass. Generators - Air drills - industrial fixings.
T
twllddu
Guest
Going up it or down it ?
M
Mine Explorer
Guest
diggerdog adam said:
The depth shouldn't make too much difference, it doesn't matter if it's 20ft or 200ft, it still hurts if you fall! That said, a 200ft pitch does sharpen the senses somewhat to dodgy rigging!
Is it underground or on the surface?
If it's a winze, what's the state of the level leading up to the pitch like? - any better rock there?
What's the shape of the passage leading up to the pitch like? - can you wedge a pole across the level further back?
Any (strong) rails in the passage leading up to the pitch?
Any (strong) compressor pipework in the region?
What's the diameter of the shaft like and what state are the edges? - can you put a scaffold pole across?
What's the floor like? - Is there enough muck to use a ground-anchor?
I wouldn't recommend it for a 200ft pitch, but exploring much shorter drops we've been known to use four or five explorers sitting in the level as a belay (best to make sure the rope between them is taught before you start, the first couple get frightened as they get pulled towards the edge if you don't!)
I wouldn't be too happy about bolting into ginging in the shaft - it usually dislodges far too easily. I suspect your best bet is looking along the passage leading up to the pitch on a case-by-case basis.
Of course, if you're on the surface it's a lot easier.
Without seeing the pitch it's hard to say anything too specific.
D
diggerdog adam
Guest
Right, thanks mine explorer The shaft entrance is on the surface but nothing avaiable to tie of to! Was thinking of using a system of spikes like the coastgaurd do for cliffe rescue (i think its a row of 3 spikes with a 2 others behind it but not sure) and then try to wedge a scaffold tube across the top it just that theres lots of water coming out of the side and i was thinking that i might need a reblay a bit further down guess i need to take a better look
bubba
Administrator
Lots of good information in Life on A Line
(see section 5 of part I for belays including ground anchors)
Life on a Line is an excellent ebook in 3 parts - entirely free download (though donations are welcome to help with the running costs of the project). It describes itself as "The online underground rope rescue manual" and is extremely thorough.
(see section 5 of part I for belays including ground anchors)
Life on a Line is an excellent ebook in 3 parts - entirely free download (though donations are welcome to help with the running costs of the project). It describes itself as "The online underground rope rescue manual" and is extremely thorough.
M
Mine Explorer
Guest
Mmm, do you have vehicular access? Presumably not. If you did then the patent pending Land Rover bolting system could be pressed into action (take the keys down with you, don't want someone driving off with your rope!)
For situations like this we have a ground anchor. There's a mine in North Wales where there's nothing near the entrance pitch to rig to. On the first club trip a Landrover starting handle was used. The rope was led over the rim of the shaft, down hill somewhat before being tied to the starting handle that had been hammered into the hillside! The friction between the rope and the soil took much of the weight, even so, the owner of the starting handle felt duty bound to stay on the surface and check everything stayed in place!
After this trip the ground anchor was constructed. This takes the form of two pieces of box section, one hinged to the other to form a 'T'. The rope is fastened to the bottom arm of the 'T'. Along the top section of 'T' are three holes, each angled against the direction of rope pull. Through the holes are placed three steel spikes, each about 18" long, these are hammered fully into the ground.
This bit of kit is very useful (and has been load tested on the surface), in some places it's the only anchor available, in others it can be used as one leg of a 'Y' hang or as a rebelay near the top of a pitch. Up in Nenthead on the through trip from Rampgill to Brownley Hill, the passage in Rampgill at the top of the pitch is all loose shale and can't be safely bolted. To get down the ground anchor is hammered into the compacted shale on the floor a reasonable distance back from the head of the pitch. (a return trip has to recover the anchor)
Your plan to use a series of spikes in the ground seems the best solution. Make sure each one is angled away from the shaft, and tie the rope at the base of the spike, so it's loaded in shear. Tie the rope around each of the spikes and remove the slack between them so they all share the load. The scaffold will also share the load, but I'd prefer to be physically tied to the spikes if possible, rather than rely on a wedged scaffold bar.
I must admit 200ft is what I might term a series pitch, you need to truely satisfy yourself that the belay ain't going anywhere and I'd tie to anything you can - passing sheep, low flying aircraft, boulders, surface crew, luchboxes etc. etc. BTW: Don't situate your anchor right at the edge of the shaft, if you put it a short distance away the rope will rub againt the soil and friction will help. (Check for sharp stones etc. in the way first!)
Regarding the possible water on the way down, I'd go down and have a look, you may find solid rock in that area where you can do a rebelay, else you may find that moving the surface anchor to the other side of the shaft avoids the problem.
Best of luck.
Mine X.
For situations like this we have a ground anchor. There's a mine in North Wales where there's nothing near the entrance pitch to rig to. On the first club trip a Landrover starting handle was used. The rope was led over the rim of the shaft, down hill somewhat before being tied to the starting handle that had been hammered into the hillside! The friction between the rope and the soil took much of the weight, even so, the owner of the starting handle felt duty bound to stay on the surface and check everything stayed in place!
After this trip the ground anchor was constructed. This takes the form of two pieces of box section, one hinged to the other to form a 'T'. The rope is fastened to the bottom arm of the 'T'. Along the top section of 'T' are three holes, each angled against the direction of rope pull. Through the holes are placed three steel spikes, each about 18" long, these are hammered fully into the ground.
This bit of kit is very useful (and has been load tested on the surface), in some places it's the only anchor available, in others it can be used as one leg of a 'Y' hang or as a rebelay near the top of a pitch. Up in Nenthead on the through trip from Rampgill to Brownley Hill, the passage in Rampgill at the top of the pitch is all loose shale and can't be safely bolted. To get down the ground anchor is hammered into the compacted shale on the floor a reasonable distance back from the head of the pitch. (a return trip has to recover the anchor)
Your plan to use a series of spikes in the ground seems the best solution. Make sure each one is angled away from the shaft, and tie the rope at the base of the spike, so it's loaded in shear. Tie the rope around each of the spikes and remove the slack between them so they all share the load. The scaffold will also share the load, but I'd prefer to be physically tied to the spikes if possible, rather than rely on a wedged scaffold bar.
I must admit 200ft is what I might term a series pitch, you need to truely satisfy yourself that the belay ain't going anywhere and I'd tie to anything you can - passing sheep, low flying aircraft, boulders, surface crew, luchboxes etc. etc. BTW: Don't situate your anchor right at the edge of the shaft, if you put it a short distance away the rope will rub againt the soil and friction will help. (Check for sharp stones etc. in the way first!)
Regarding the possible water on the way down, I'd go down and have a look, you may find solid rock in that area where you can do a rebelay, else you may find that moving the surface anchor to the other side of the shaft avoids the problem.
Best of luck.
Mine X.
D
diggerdog adam
Guest
Top advice blokes thanks. I can see the welder coming out before long !
M
Mine Explorer
Guest
diggerdog adam said:
OOooooo, I nearly forgot. Very important to make sure your spikes have a cross bar or somthing similar across the top (to turn it into a 'T') you really don't want the rope or scaffold bar to slip off the top of the spike. I know it's unlikely with the spikes angled away from the direction of pull, but that's not much help when it happens whilst climbing up the pitch! :shock:
D
diggerdog adam
Guest
Mine ex,
Had another look today spoke with the local farmer and he said for years its been used for tipping s/crap down etc so looks like it might be a no go before we start. same old same old big hole fill with rubbish ! + all the top few courses of stone are deadly loose for extra fun!
Bugger
Had another look today spoke with the local farmer and he said for years its been used for tipping s/crap down etc so looks like it might be a no go before we start. same old same old big hole fill with rubbish ! + all the top few courses of stone are deadly loose for extra fun!
Bugger
M
Mine Explorer
Guest
diggerdog adam said:
Oh well, usual story then.
Still worth a look though, just 'cos the bottom is likely to be blocked, there may be another level that enters the shaft above the blockage?There are even techniques to avoid dislodging loose stones at the top if you really want to get down the shaft 8)
Mine X.
PS: Have you done the traditional dropped stone depth test....
...drop stone, count seconds in your head, multiply by two for good measure then multiply by twelve to convert to feet. - Not very accurate but does tell you if there's only 30ft left
ian mckenzie
New member
Mine Explorer said:
The formula is D=5t2 (Depth in metres = 5 x the number of seconds squared), or in feet D=16t2 .
Ian,
<boring pedantry>
From my memory of basic physics the acceleration due to gravity is about 9.8m/s2. This value is a constant and not dependent on size or mass of the object (also it ignores wind resistance etc.).
This basically translates to: in 1 sec an object will fall 9.8m, in 2 seconds it will fall 29.4m (9.8m in the 1st second and 2x9.8m in the 2nd second), in 3 seconds it will fall 58.6m (9.8 in 1st second, 2x9.8 in 2nd second and 3x9.8 in 3rd second) and so on.
Time________Depth___D=5t2
(Seconds)____(m)
1___________9.8m_____5m (=5x1x1)
2__________29.4m_____20m (=5x2x2)
3__________58.6m_____45m (=5x3x3)
4___________98m______80m (=5x4x4)
etc.
</boring pedantry>
Although come to think of it there always seems to be a bull s**t factor applied to estimating the depth of a pitch (e.g. count as fast as you can in your head and then double it for the pub version) so your method is probably more accurate - also the actual acceleration will vary depending where you are in the world - less at altitude for example - so good for the high altitude Peruvian stuff you've been to (respect).
<boring pedantry>
From my memory of basic physics the acceleration due to gravity is about 9.8m/s2. This value is a constant and not dependent on size or mass of the object (also it ignores wind resistance etc.).
This basically translates to: in 1 sec an object will fall 9.8m, in 2 seconds it will fall 29.4m (9.8m in the 1st second and 2x9.8m in the 2nd second), in 3 seconds it will fall 58.6m (9.8 in 1st second, 2x9.8 in 2nd second and 3x9.8 in 3rd second) and so on.
Time________Depth___D=5t2
(Seconds)____(m)
1___________9.8m_____5m (=5x1x1)
2__________29.4m_____20m (=5x2x2)
3__________58.6m_____45m (=5x3x3)
4___________98m______80m (=5x4x4)
etc.
</boring pedantry>
Although come to think of it there always seems to be a bull s**t factor applied to estimating the depth of a pitch (e.g. count as fast as you can in your head and then double it for the pub version) so your method is probably more accurate - also the actual acceleration will vary depending where you are in the world - less at altitude for example - so good for the high altitude Peruvian stuff you've been to (respect).
