Death's Head Hole - New surface anchors
A few weeks ago we issued a warning about the poor condition of the tree in the Death’s Head Hole entrance. This has been used as a belay for descending the shakehole for many years (backed up by some rather dubious fence posts), so presented a potential hazard to visiting cavers.
We erroneously attributed this to ash dieback; In fact, the tree is rowan!
A team of three CNCC conservation volunteers (Hugh Parker, Tim Sullivan and Ged Benn) went to Death’s Head Hole on Sunday 2nd April to attend to the problem rowan. After prior consultation, it had been decided, that instead of removing it completely, it was better to take out just the head off the tree to reduce wind-drag on the trunk and remove any dead branches. Leaving the lower part of the tree including much of the trunk will help preserve the roots which may be stabilising the side of the shakehole.
Photo 1: Pruning the worst from the dead tree (photo by Ged Benn).
Photo 2: From below, showing that leaving as much of the tree as possible in place was desirable as the roots are stabilising the top of the hole (photo by Hugh Parker)
The pruning work was quickly accomplished, but once branches were cleared it was obvious that the heart of the tree is rotten and hollow so further treatment will eventually be required. For now though, it can remain in place. The tatty sling which has been there for some time judging by its faded colour was removed.
Continued use of the remaining trunk as a belay is not recommended, particularly as the approach to the first anchor is a steep and exposed gully above a very deep pitch. We needed another solution, but unfortunately the surface lacked solid rock for any additional resin bonded anchors to be installed.
After considerable discussion amongst the CNCC anchor installers team, with lots of excellent input, the decision was made to manufacture and install ground spike belays.
Photo 3: Ground anchor bars cut to a spike on one end, ready to be installed (photo by Ian Patrick).
On 7th April, a bright sunny day, a CNCC team including our Training Officer/Anchor Installer, Ian Patrick, headed up to Death’s Head hole armed with two 38mm diameter, 1.3m long galvanised steel tubes with thick wall with pre-cut spike end, plus anchor installation equipment and an assortment of rigging kit and other tools.
These two poles were successfully installed just outside the fence, hammered 1m into the ground, 1m apart to allow a Y-hang to be rigged from them. The rope can be rigged under the fence which conveniently helps prevent it coming off the top of the poles (although once under tension this is extremely unlikely).
Work was finished when the sledgehammer-induced mushrooming on the tops of the poles was smoothed off to remove sharp bits and bright green tape was wrapped around the top to help them be seen and avoid anyone falling over them. An old and rather less sturdy rebar stake was removed.
Photos 4-6: Installation of the new ground spikes (photos by Ian Patrick).
Despite best efforts, Ian was not able to install any stainless steel resin bonded anchors within the shakehole. The ground was too loose. However, he was able to get one extra anchor into the gully about 1.5m above the top of the existing first pitch anchor, to serve as a rebelay part way down the gully. The existing single anchor on the start of the first pitch was supplemented by a second to convert this into a Y-hang to minimise fall factors.
In summary, the Death’s Head Hole rigging now comprises a Y-hang from two scaffold ground spikes just outside the fence, a rebelay/traverse anchor in the gully, and then 1.5m lower is a Y-hang for the first proper pitch. The rigging topo has been updated accordingly, although the rope length is unchanged (80m)
The hollow tree trunk is still present, but we recommend that this is not used for rigging.
Cavers are reminded that, unlike our stainless steel resin bonded anchors, these ground spike belays do not carry years of evidence for their longevity. It is essential that all cavers must inspect and be satisfied in the integrity of the ground spikes before using them; the same of course being true for all anchors! Report any issues you observe.
This has been a significant project for several CNCC volunteers, with input from tree experts, our conservation volunteers, and the anchor installation team, with work spanning three days. Thank you to everyone involved, both hands-on and behind the scenes.
There are plans to return in due course to plant a selection of new trees around the entrance.