Broadside NW: Time For A New Approach?
14 July 2007 by Tom Foord
We had a new recruit today, Emma Heron, who was keen for some digging action since her usual team of Eastwater and Daren diggers were all away on foreign expedition. Alan, Keith and I were keen to show her the delights of Aggy digging, but as it happens it turned out to be a bit of a baptism by fire.
We made our way to Broadside in 2h 50m, taking in the sights of Trafalgar Passage on the way. The objective today was to continue digging downwards in Broadside NW in search of a way on. But as we started to dig we immediately discovered that this was not going to be as simple as we had anticipated.
Until now we have been digging down through dry mud which is easily broken up by a crowbar. But now we had hit a layer of extremely heavy clay of a dark reddish colour. This stuff is like plasticine, but harder, heavier, and less flexible. By continually hammering away at it with the pointy end of a crowbar, lumps of it could be slowly peeled off, but this was extremely slow and hard work. After several hours we had removed just 30 trays, some of which were only half full, and the effort was taking its toll on all of us. In addition the ‘arch’ feature we had been following down had again pinched out into a narrow crack, so things weren’t looking too promising. Time for a rethink.
The heavy clay we have hit is not a good sign, as this is not indicative of water flow. It either means we are in a dead end alcove, or perhaps, as Alan suggested, that we have just about reached the floor of the passage (we are, after all, well over 3 metres down!) This theory is also reinforced by the scattering of rocks we have now been finding within the fill. There is also no scalloping on the walls, despite there being some fairly good examples a few metres back down the passage. All the signs point to us being in the wrong place.
With that in mind, we contemplated a trial horizontal dig following the wall, either at the bottom of or halfway down the pit. But with the air starting to turn a bit nasty in the pit we thought it may be more sensible to try at roof level first. For the last half hour we dug across to the wall to the left just before the pit, removing loose sandy mud. In fact we found there were layers of very coarse grained sand here, indicating fast flowing water. This will be well worth pursuing next time, and the aim will be to follow the wall all the way around the end ‘chamber’ to get an idea of the true shape and orientation of the passage here.
In total we had removed a measly 43 trays of spoil on a 12 1/2 hour trip. Not great progress, but considering the conditions in the pit this was quite an achievement. At least we have opened up new options and have something to focus on next time. Broadside NW is not dead yet!
6 Comments Add your own
1. Martin | July 16th, 2007 at 11:31 am
Sounds like the 4 of you showed plenty of zeal.
Although it is a shame that it didn’t ‘go’ via the pit that we’ve dug, this might not be such a bad thing. If the way on was / is down this pit, then itwould make things quite difficult to dig at such a depth (air quality) and remove spoil (lifting trays out of the pit). If it goes at a higher level to the left, then that might make things easier in the long run.
I reckon we should aim to remove spoil all the way back to Broadside still. The pit will one day come in handy for backfilling – if we go under to the left, then we might well need a forward spoil heap (the pit).
If you look at the passage shape that we have dug to the end, there is a definite kink right at the end, so there is every possibility that left of where we have been digging is the place to be.
2. Tom Foord | July 16th, 2007 at 2:39 pm
Agreed Martin, we should keep the pit there for the time being until we have a more definite idea of where we want to go. Spoil removal is dead easy back to Broadside anyway, especially with 4 people.
The pit also adds an element of excitement to the digging, as there’s the constant possibility of a 3 metre plummet to the bottom if you shuffle a few of centimetres in the wrong direction! Certainly keeps you on your toes!
3. Alan | July 16th, 2007 at 3:49 pm
If the pit isn’t part of a phreatic loop, it does at least suggest that we’re following a reasonable sized passage.
4. Martin | July 16th, 2007 at 10:02 pm
I agree that the pit will add to the excitement and that can only be a good thing.
The more I think about this, I think it is quite a good result. We have got to the stage where we know that something needs to change. We have created a good forward spoil heap. We will not break through before John and Arthur can be back with us. We will give Mathias some more time to get down there before the action really kicks off.
The feature that we were following at the start was a linear crack in the roof. We should have every reason to believe that this feature will continue going in a straight line (and not bend to the right like the wall we have been following does).
I think that what we should do now is to traverse that back wall leftwards at a comfortable depth (like the depth of the main dig towards the pit). This should show where there is a good looking place to dig down and once we have hit the left wall, we will know the extent of the passage.
I’m looking forward to more burly days digging down there.
5. Alan | July 17th, 2007 at 9:25 am
... or it could turn to the left, in line with the original feature that we found when we started to enlarge rightwards.
6. Goydenman | July 17th, 2007 at 4:10 pm
I suspect you will end up using the pit and doubt it will be a waste of time – here’s to you finding the way on. Following the clues is what it is all about eh!
Took guys from our club down new entrance into impressive New Goyden with railway size tunnel and streamway. They were well impresed especially as they did not need to use SRT gear as for older entrance, good digging session to end with.
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