In February 2011, a visit to Odin Mine discovered a serious collapse in the entrance level at the base of the first 'up' pitch, leaving a large and very deep hole where the floor used to be. The spoil had fallen through to the next level, part-blocking the route into the stone-stempled passage leading to the Cartgate chamber. As the site is owned by the National Trust and is on CROW land, this triggered alarm in their legal department, and cavers were asked to keep out whilst the situation was reviewed. As this section of the mine is predominately roofed by shale, with floors of (now-proven) dubious stability, safety had understandably become a serious issue. Several inspection visits were arranged, which took a few years, as the collapse took a long time to settle and visits with many people take a long time to arrange. Several more years elapsed with not much happening, mainly due to bureaucracy and the obvious reservations about how to deal with a potentially dangerous site on public-access land. Eventually, after much begging, the DCA was given permission to make a 'caver-specific' inspection in 2019, with a qualified mine inspector with experience of abandoned mines, with a view to establishing the stability (or otherwise) of the remaining areas of the ‘trade route’ to the terminal Cartgate chamber, and producing solutions to resolve the new hazards.
These solutions were subsequently accepted, and then applications to do the work had to be made to Natural England, as the site is within the Castleton SSSI, and also to Historic England, as the site is a Scheduled Monument and we needed to modify it. Whilst formalities, these took yet more time, and so it wasn't until January 2020 that DCA were able to begin a bolting programme to overcome the collapse and bring the rest of the fixtures up-to-date. DCA anchor policy states that all significant vertical pitches should be double-rigged with two anchors, but virtually all vertical pitches on the trade route were single DMM P-anchors of uncertain age, so these had to be pull-tested (all passed) and have been doubled-up where necessary, and additional backup anchors installed where the existing anchors were insufficient, or non-existent.
The floor-collapse was in an area of particularly complex (and fragile) geology, and conventional anchor systems proved ineffective in certain patches due to a thick layer of orange fluorspar with the appearance, strength, and consistency of barley-sugar. So, we had a set of special 600mm stainless throughbolts manufactured by Bolt Products to reach the limestone behind. Resin P-anchors were used in all areas where clean limestone was accessible (photos of the collapse-hole traverse bolting below). A few sessions were completed before Covid-19 struck, and the series of endless lockdowns and releases commenced. Owing to the complexity of the problems, the need to pull-test all anchors, old and new, and the constant interruptions due to Covid restrictions, we have only just completed the work in April 2021, but the site is now 'good to go'.
As gating and booking access to the site are both impractical, the site will be 'open access', but the National Trust have requested that we advise that ALL visitors MUST have BCA public liability insurance. As the site does contain higher risks than many mines, it is imperative that visitors approach the site with care and attention, particularly as rescues would be extremely complex and time-consuming, and with greater risks to the rescuers. Many changes have taken place since the site's closure, the most significant of which are listed below, and should be noted carefully as they significantly affect access. Also, many cavers have never visited the site before due to the ten years-long closure.
• The NT removed the collapsed tree-trunk from the gorge-climb two years ago, meaning it is now almost impossible to climb up to the entrance this way - the rock is extremely slippery, and there is a high chance of a serious accident due to the height of the boulders and steep slope - do not attempt this route.
• Recent collapses of rock from high above the lower gorge mean that this area is currently fenced-off by the NT and is still dangerous. Some hanging rock has recently been brought down for safety, but more will fall, so please keep out of the lower gorge at all times.
• Access to the mine entrance should be made up the right-hand (north) slope to the shale boundary, and then either follow the tiny shale path branching to the left around the rim of the gorge (care) or go higher to the large tree that overlooks the entrance area. The safest way to access the entrance boulder-platform is via a pull-through rigged around the large tree (30m rope required). This also means no ropes are left visible for thieves. A single old P-anchor is available at floor-level on the limestone contact but rigging and rope-access for this has to be done from above and is thus very risky.
• Once on the boulder platform, note two further new P-anchors on the north wall to rig a pull-through with the same 30m rope safely down the gorge upon exit. The single P-anchor above is too high to reach, so if you did use this method to access, climb back up the rope to de-rig (care!).
• The entrance to the mine is a 4m sloping pitch in a tight slot down a tree-trunk, via the lower section of the right-hand vein cavity only - the left vein is unbolted and very loose. New anchors have been provided with backups. Inside the mine, tie off the rope at a P-anchor on the right-hand wall.
• The floor collapse is 50m along the entrance level, and bolts for a safety traverse are on the right-hand wall – there are double anchors at each end, and the floor hole is large enough that nine connectors will be required to safely rig the rope across the hole. There are two protruding bolt-ends on anchors that still need to be cut off, so please be careful here.
• The collapse hole is through very loose shale backfill and is NOT a pitch. Do not attempt to abseil down this hole under any circumstances – you could kill yourself or others and close the mine for ever.
• The former ‘handline climb’ which follows the traverse, is a slippery climb up a shale-covered sloping false floor, and the top half is an awkward vertical thrutch through a tight slot with crumbly walls. Due to the collapse hole and the difficulty of rigging from below, this route is now SRT-only, and has been pre-rigged by DCA on brand-new rope, tied direct into the anchors. Please inspect this rope before use, and do not use if you spot damage. Please report any damage to DCA immediately. A via ferrata step has also been placed to aid bolting and may be useful to aid climbing, but this can be removed if it proves more problematic than helpful.
• The debris from the collapse part-blocks the entrance to the stone-stempled passage, and care should be taken when entering or leaving. It would be helpful if visitors could dig this out more to reduce the risk of touching the first stemple.
• The lowest pitch down from the Bell Chamber off the Cartgate is one for the geologists, and whilst a great example of vein working, it should be treated with great caution, although it is fitted with DMM P-anchors. The entrance is through a gap between enormous slabs of collapsed vein, many more of which are hanging overhead and are the base of the boulder choke in the Cartgate, so do not touch anything other than the anchors, which have no backup due to the lack of suitable space. There is no way on at the base of the pitch, and it’s totally blocked with deads in both directions.
The rest of the route is more or less as described in COPD and in the provided Micro Guide, with all anchors backed-up. Please consult the rigging topo carefully before setting off, as not enough rope, or the wrong lengths, could result in significant problems. The anchor route is designed for SRT, but ladders may be safely used on all the internal pitches after the fixed rigging.
An important point for new visitors to note about Odin is the shale – the top (entrance/exit) section is entirely roofed with shale with a false floor of uncertain depth, and small collapses (and large ones!) can and do happen all the time – please be aware of the need to be extra-careful, and leave immediately if anything significant falls from the roof. It is also extremely slippery, and hand and footholds that work on limestone may not work on shale, so again, please factor this in before attempting free moves over drops. It is more tiring to traverse over than limestone and will sap energy, particularly on the exit with steep awkward slopes to negotiate. Please be aware of your energy reserves and try to keep groups to small numbers to avoid congestion in small or tight spaces.
Finally, and most obviously, it is extremely dirty. All trips to Odin will involve trudging through or being coated by thick, black mud, and the entrance (or exit!) are the worst parts, due to the shale and the endless dead leaves that coat the floor. You will get very dirty, and it is much more difficult to wash off than sediment and will take much longer. So again, factor this into your trip estimation.
As Odin Mine is in a very public area and CROW land, it is quite likely that you may encounter members of the public on visits, and it is imperative that they are left with a good impression of cavers – but also imperative that they are treated with respect and are not put in any danger by us.
Also remember that the National Trust are taking something of a gamble with the site and are to some extent relying on DCA to encourage proper access – though we obviously can’t police it for them. So please use the site wisely and safely – it’s an important historic and geological resource and extremely interesting and quite challenging to visit but does have significant risks attached and we can’t afford any scandals at this stage. But we hope you enjoy your trip.
Further information is provided on the Cave Registry site, with rigging topos, original survey and a Micro Guide, along with references for further reading. The COPD description for this entry has also been unlocked to provide maximum information:https://peakdistrictcaving.info/home/the-caves/castleton/odin-mine