It is sometimes really hard to relate the minerals I see underground to the professional sample pictures on places like Wiki and Google. All I wanted was to be sure that what I saw was a certain thing. Well, I’ve started a Flickr album showing actual minerals in actual mines in the hope that I can make it easier for everyone else to identify what you’re looking at. There are loads of omissions still, but it is a start!
Rumers have been circulating for a while now about a redesigned Petzl Stop being in development and test. The first pictures have now emerged following an expo in China. Thanks to Qi Woo for posting these on the Rope Test Lab Facebook Group. I have made a few limited observations based on these few images.
From this pre-sale version, we can see the device remains an assisted braking descender but is now marked as certified to EN 15151-2 (2012), which is the “Breaking Device” standard and indicates this can be used as an assisted belay device, which the previous version was not certified to. This would be a major draw for instructed caving where there is a shift away from ‘historical’ use of the current Stop and towards devices with full certification for each job we ask them to do while at work. It’ll be interesting to see this new Stop go head to head with the RIG2 device which is being picked up by more and more cave leaders.
The new Stop is compatible with 8.5mm to 11mm ropes, which just about covers the full range of diameters cavers are likely to need, although not quite down to the 8mm stuff which is becoming more popular with sport cavers. Interestingly, the new Croll S is compatible with 8-11mm rope.
The assisted braking / control handle has changed from a push-in to a pull-down style operation, much like the Petzl RIG or Kong Indy Evo, something that will be welcomed by some, but disliked by others. I am happy about this, as I’m someone who has started to develop hand pain from the current squeeze operated handle after longer trips or many lowered clients.
The device no longer seems to have user replaceable bobbins, as evidenced by the lack of hex head nuts and bolts on the frame. It does seem that both bobbins are made from the same metal, making me think this is a full stainless steel bobbin device, which should give much longer lifespan over the alloy bobbin version. We should also see an end to grey ropes in the kit store now there is no alloy to wear and coat the rope.
We’ll need to wait and see what that little hole is for in the handle. Remote braking release perhaps or just a pre-production moulding feature?
I have not seen a release date for the UK market yet and I look forward to getting my hands on the user instructions when they are issued. What will be very interesting to see is specifically how Petzl supports the use of this device for lifelining (and rescue hauling) as it might be used in instructed caving. Could this be the Stop we’ve always wanted, or will the professional caving market continue to migrate to the excellent RIG2 device, with its multi-function EN standard compliance?
In addition to the Stop pictures, we can see a completely redesigned Freino krab, with its braking spur repositioned to the opposite end of the karabiner when compared to the previous version. Eagle eyed readers will spot that this krab is attached to a red device in the photo below. We are also looking at a new version of the Petzl Simple. This does still have hex head bolts so may retain its user-replicable bobbins. They bobbins even seem to be symmetrical, making them reversible too.
I’m sure we’ll see more in the coming weeks.
I’ll get my hands on one of these new Stops as soon as they become available. Until then, if you need to talk about lifelining or abseil devices appropriate to your underground operation, feel free to get in touch. For technical advice to the outdoor industry or LCMLA courses, see www.undergroundspecialist.co.uk
Holmebank Chert Mine
Fan Entrance lock installation 9th January 2018
Today I was up at Holmebank Chert Mine near Bakewell on behalf of the Derbyshire Caving Association and the Peak Instructed Caving Affiliation. One of the access points to the mine required a new locking mechanism which allowed explorers to access the locking bolt from inside and out.
Using some high strength steel components bought by the DCA, I fabricated up a simple rotating hatch, allowing a person to reach through and access the sliding bolt on the inside of the gate. The hatch is locked with a combination padlock and cavers can obtain the code from the usual source. Currently it is set to the same combination as the other lock on the top entrance.
Many thanks to Ewan Cameron from Evolution Outdoors for the company and assistance installing the hatch today and of course to Joe at the architects firm for his continued support of access to the mine for outdoor centres and instructor training.
A Method of Testing the Strength of Heavy Duty Caving Belts
The aim of this little test was to establish a method to test the strength of heavy duty caving belts that did not rely on having access to a load cell. I hoped to produce a simple system that needed very little equipment and that would deliver a test load to a belt that exceeded the minimum strength requirement for its use.
What strength does a belt need to be?
Well, this one is a potential can of worms…. Let’s be clear, the manufacturers do not condone the use of their heavy duty belts for taking any load at all. There is a historical use in cave and mine exploration that involves using the belt for the purpose of slip prevention and security on steep ground. If you were intending to use it for this purpose, you’d need to be sure that the belt was strong enough for that, something that the manufacturers will not say.
We take the figure for a heavy person with kit that is used for some load ratings on PPE equipment: 120kg.
If a caver has a short lanyard which they climb above, ignoring all stretch or slack in a system, we will assume a possible fall of 1 metre onto the belt. The person will then be travelling 9.81 m/s (acceleration due to gravity).
velocity = √ (distance x gravity x 2)
v = √ (1 x 9.81 x 2)
v = 4.43 m/s
Kinetic energy = (v²m)/2
Ke = (4.43² x 120)/2
Ke = 117.72 J
Impact force = Kinetic energy / Impact distance
iF = 117.72 / 0.1 (arbitrary minimum for complete stop)
iF = 1177.2 N
Impact Force = 1.177 kN
Force = Mass x Acceleration
F = 120 x 9.81
F = 1177.2 N / 1.177kN
So a 1m drop of a 120kg caver onto a belt, not taking into account any stretch or bounce, produces a force of nearly 1.2kN.
Apply to this any safety factor you wish. Worse case? Twice the force falling onto half the strength of kit due to wear and age: 2 x 1.2kN = 2.4kN force will need to be held for a worst case fall and we halve the strength for old, worn or wet kit so 2 x 2.4kN = 4.8kN.
So as long as we can apply a test force of 4.8kN or more to the belt, we can be assured that the item can hold the greatest possible force we can apply to it even if not in new condition. The only remaining factor of concern is that would applying this force in test render the belt unsafe to use again, in essence, are these tests destructive? Only 1 way find out…..
You could easily argue that this figure is seriously overkill for a belt so you should undertake your own discussion as to the correct safety factor to apply and then make sure you test to that, e.g. 2.4kN using 2 or 3 people on the 3:1 MA system.
Using 1 very large Corsican Pine and a good sized Birch tree, we set up a pull testing rig with a simple 3:1 theoretical configuration. I used a Rock Exotica load cell to get live feedback on the testing here but if you copy the method, you would not need to use one.
For the estimation of test force we regarded each person capable of pulling 50kg (see Gethin Thomas’ work on tyroleans). Through a theoretical 3:1 MA system that would be 150kg per person. With 5 undertaking the pull reaching 750kg and 6 equalling 900kg or approximately 7.5kn and 9kN respectively.
Kit used (minus load cell): Petzl rescue pulley, Petzl Basic jammer, Petzl Partner pulley, Lyon wire sling for tree, assorted karabiners, 20m rope.
Due to the force expected to be placed on the rope, I did not anticipate that I would be able to untie the end knot (fig 8 loop). This was accurate and the knot had to be cut from the rope end. Bare this in mind with your own rope!
We also used a Petzl Rollclip to redirect the angle of pull to make it easier to stand on the tarmac of the road alongside the trees.
Initially we had 5 people pulling the first test on a Lyon roller-buckle belt (brand new).
This produced a force of 5.9kN with no damage or slippage. This is lower than expected but there was a lot of tightening in the knot and stretch in the rope coupled with a general timidness of the pulling team.
The remaining tests used 6 people to pull. This one was conducted on my 10 year old Caving Supplies square buckle belt (already retired). This belt has nicks, fluff and rust and comfortably took a force of 7.74kN showing no damage or slippage. Next came my current AV belt, with it’s central maillon removed and directly attached to the pull line. This belt held 7.7kN without failure or slippage.Finally, the pulling team seemed at their most confident that nothing was going to break and send shards of metal and wood at them so they really gave the last belt some pain. This Warmbac square buckle belt was subjected to 8.64kN with no damage or slippage noted at the time.It is not surprising that the force exerted by the pulling team was less than the theoretical 3:1 system implied. In practice with the loss of friction due to bearings and turns in the rope a 2.5:1 is a more real world figure and so our 5 x 50kg pulling average adults could be expected to make 500kg/5kN using this system. Add a 6th person if the ground is poor or your team are small!
Using a system like the one shown here, with 5 people pulling at average strengths, you can apply a force greater than 4.8kN to your test belt.
Once the test is complete you should thoroughly examine the belt to see if any damage or slippage has occurred. Any that do show signs of damage should be retired. Any slippage may be down to the buckle tightening down so consider testing again. If a belt has taken the test load and shows no damage or deformity then you can be comfortably sure that the belt will be fit for its intended use.
Final inspection of belts:
Lyon roller buckle 5.9kN No damage, continuing to use.
Caving Supplies square buckle 7.74kN No damage, already retired.
AV maillon closed harness buckle 7.7kN No damage, continuing to use.
Warmbac square buckle 8.64kN No damage, slight curvature to webbing now when hung vertically which indicates over stretching or broken fibres down one side. Retired from service.
As a side note, I maintain that the Caving Supplies belts are the tanks of the heavy duty caving belt world and, if kept very clean, will ultimately outperform every other type or brand available. I think this test shows that well as the CS belt had at least 5 more years of abuse over the other belts. I will dispose of the Warmbac belt just in case but don’t tend to use these anyway, but that’s another blog post!
I guess this post is a bit of a continuation from the blog post I did about pull testing SPIT type anchors in 2015. Sorry it has taken me so long to get round to doing this!
The original post can be seen here: http://www.peakinstruction.com/blog/pulling-spit-anchors-back-garden-test/.
One of the points of that testing was to ascertain if the sleeve anchors could be removed from the rock in a cave or mine to either de-clutter the wall or allow a resin anchor to be placed in the same location. This is important from a conservation point of view, these sleeve anchors are a bolt rash on the walls of our caves and once stripped of threads, are there forever…. or so I thought.
Jump ahead to now. Simon Wilson has developed the IC Resin Anchor in the Dales and his website has expanded to become a good resource of information relating to the installation and removal of anchors. Most relevant here is the method that he uses to remove old sleeve anchors, one which I am shamelessly copying here in an effort to spread the knowledge and encourage the tidying up of pitch heads. Simon’s site is here: http://www.resinanchor.co.uk/5.html.
I started with the original block of Stoney Dale limestone used for the original testing in 2015.
- If required, dress the rock near your anchor sleeve with a chisel to create a flat area for drilling.
- Drill a 6 or 7mm hole immediately next to the anchor sleeve.
- Drill a second hole parallel to and as close to the first as possible.
- Bore out into a slot using an old drill bit and some wiggling.
- Tap the anchor sleeve into the slot using a cold chisel or old screwdriver.
- Remove the anchor from the hole. This may well need some jiggling about or a bit of extra chiselling. If possible, screw a bolt into the sleeve to aid extraction.
- Fill hole with resin or drill out for the installation of a new resin anchor.
Shown with a SPIT 12mm self drilling anchor:
SPIT 12mm self drilling anchor that had sheared off in a previous test:
Another SPIT 12mm self drilling anchor that had sheared off in a previous test:
This removal method works well once you’ve had a little practice and was far less destructive or time consuming than pulling the anchors out with the HAT-28. I also used the same method successfully to remove 10mm lipped sleeve anchors as well (HKD / drop-ins etc…) although have no photos.
As I was drilling so close to the sleeves, occasionally hitting them, this was very hard on drill bits. I melted the head off my cheap 7mm half way through and swapped to the 6mm bit. I’ve just ordered some quad tipped bits from Hilti in the hope that they are tougher. I’ve only ever destroyed one of them in the tough welsh rhyolite of Parc mine.
The remaining triangular hole can then be cleaned out and filled in using an expired resin cartridge with some limestone dust thrown on. It won’t disappear 100% but will be a huge improvement over the old rusty sleeve.
If you plan on re-using the hole for a new anchor, try to position your slot to the intended orientation of the head of a ‘P’ style resin anchor. Once the anchor is placed, make sure the whole hole is filled with resin leaving no voids. You can’t use the SPIT resin vials for this job as they have a set quantity of contents, you will need to have a resin cartridge gun to fill the irregular hole properly.
I hope to begin removing some of the decades of old sleeve anchors in sites now resin bolted and potentially earn some karma points back for anchors of this type that I myself have placed in the past prior to my ‘enlightenment’.
Thanks for reading.
Caving ladders are an integral part of the LCMLA Level 2 award. Being practiced with a ladder not only saves time but lots of faff. It can be hard to pack loosely coiled ladders into tackle bags, meaning they get dragged and thrown about the cave, something that no kit really deserves. Practice coiling your ladders and look well polished on your assessment and in front of your clients.
It’s now March 2014, about a year and a half after I bought my first length of the Gleistein Geostatic 9mm rope.
The 31m length I bought was soaked at home and measured to 32m, no doubt down to Shaun at Hitch N Hike’s generous measuring style!
I labelled it up as a 30m and went about using it.
I re-measured it today and it came in just over 29m, a shrink of 3m since initial cutting, approx. 9%. So it seems, just like any other rope, once it’s cut you still need to factor in about 10% for shrinkage over the life of the rope. I’m still happy because there was no noticeable shrinkage after cutting and soaking when first purchased in Sept 2012.
I have a 21m length bought about a year ago that has just re-measured to 19m. This length has had a hard life already, it is my traveling rope on cave leading work and has been dragged through numerous Italian hitches whist being covered in grit and the particularly abrasive mud in Peak Cavern’s trade routes. It has done a good job at sawing through my alloy krabs but the rope itself is still in excellent condition. There is some light fluffing on the sheath comparable with some of my far less used ropes and the colour, like the 29m length, has faded into a more pastel orange. It still handles extremely well, clearly not as supple as when new but a massive improvement over the 2-3 yr old Mammut 9mm I have, which is more akin to wire cable now.
My cleaning regime for all my semi-static ropes is simple and it gets done after every trip. For clean trips it is just a spray with the hose or a dunk in clean water to remove particles from the surface. More often than not it gets a low power jet wash (controversial I know!). Never force dried, only hung in a spare room or over the bath.
I’ve got 3 lengths now, each bought about 6 months apart and will continue to purchase this rope as my current ones approach retirement.
In another year and a half, when this rope is no longer in service I’ll do a final post mortem report. I’d also like to send a few samples to be tested by the BCA and Bob Mehew to see what toll the hard life has taken on it.
Gleistein is still available at Hitch N Hike as cut lengths or entire reels: http://www.hitchnhike.co.uk/acatalog/gleistein-9mm-geostatic-ne.html
The initial blog post is here: http://www.peakinstruction.com/blog/first-look-at-gleistein-geostatic-ne-9mm-semi-static-rope/
On the 27th July 2013 a storm hit the UK, falling on dry ground and empty watercourses the rainfall soon entered the cave systems of the Peak District. My wife and I took the opportunity to visit Bagshawe Cavern in flood condition.
WARNING – Never enter a cave in flood or at risk of flood without proper experience and training, even then think twice! Both myself and Beth have visited Bagshawe dozens of times and know it intimately.
Over the previous 30 days up until the 27th July the Castleton area had only received 26mm of rainfall according to the Peak District Caving Info website.
Rivers were very low and underground, the streamways and sumps of the Peak District were in a typical very low summer state.
The ground conditions were dry, not parched as there had been 11mm of rainfall on the 23/7/13. Observations after this rain showed no change in surface or underground streamways.
At 20h00 on the 27th July 2013 a storm from the South began to pass over the Peak District. Approximately 80mm of rainfall fell in the area over the next 12 hours. This caused localised flooding, swollen rivers and streams and, as expected, flood conditions underground.
For more photos see here: http://www.flickr.com/photos/peakinstruction/sets/72157634832233688/
For a non-flood view of the Dungeon Pitch see here: http://www.flickr.com/photos/peakinstruction/sets/72157634832233688/
We made our way upstream to the area just before the 1st crawl up and over rocks on the left. We could have got through but it would have been a swim. The stream level varied from calves to knee deep.
You could visit the initial main sections of the system today without risk of flooding, from the entrance to the base of the steps by the Dungeon Pitch. Although more drippy than usual, the puddles in the miner’s level hadn’t filled back up to normal high levels and were surprisingly still low.
Across the hill, Peak Cavern’s resurgence had gone from the lowest level for some time to full-on flood level discharge in 12 hours. This speed and volume was interesting as the system normally shows more of a delay in response during Summer. Something to consider there for all leaders in the system.
Recently I have been spending a lot of time swinging about on the surface, either through testing knots or coaching SRT skills. For all of this I’ve been using the excellent tower facility up at Pindale Farm near Castleton.
The SRT platform offers scaffolding bar belays and back-ups and the surrounding walls of the old mining buildings are equipped with many 8mm anchor sleeves (Spits) and a few alloy Troll hangers. You can rig just about any permutation of SRT pitch your brain could possibly come up with.
Using the tower over the past few years I’d noticed the deterioration in some of the anchors and as I was such a frequent user I thought some of the replacement anchors should be paid for out of my pocket.
Yesterday (19th March 2013) I managed to procure both equipment and assistance.
Jez Parr CIC (contact) was kind enough to loan me his SDS drill and all the bits for the job.
Nigel Ball CIC (Website) donated half of the anchors and 90% of the expertise in the operation.
We placed 4 new Petzl P38 Longlife anchors on the main wall of the facility; a line of 3 forming a traverse and pitch head which then drops to a rebelay or deviation on the 4th anchor.
We also lubricated and cleaned out all of the 8mm sleeves with a threaded tap to give them a new lease of life.
The tower is now a mix of anchors and can be used with or without hanger plates. Please bare in mind that the tower is equipped by volunteers/individuals and is on private land so booking is essential. Users are reminded to check the anchors they use are safe before commiting their life to them as they would underground and that anchors should never be used alone but as part of a safety chain.
All bolts will fail at some point, and that is when you need the Tool King Inc metal services.
Pindale Farm is an excellent place to stay in the Peak for caving or any other reason. They have camping and bunkhouses on their site as well as the excellent SRT tower.
Thinking that 2 heads were better than one I set out today with a good friend and colleague, Jez Parr. Jez in another CIC holder with many years of experience. He was also my mentor through the CIC scheme and the ideal person to bounce ideas off.
Our first stop was local gear shop and purveyor of lovely shiny things, Hitch N Hike. We purchased 5 metre lengths of all the most commonly used semi-static rope they had, in both 9 & 10mm. We have already bought a pair of Fall arrest systems online and placed them on our roof for further tests to check the tensile strength of the rope which we just bought later. So be ready to check out our next post as well.
The test this time was set up identically to the ones done previously on the 8th Jan. We had a mock Y-hang arrangement that allowed us to position the test ropes at varying heights and angles as well as a solid bar from which to rig a secure dynamic safety back-up for ourselves.
The aim of the first testing done previously was to identify the main contributing factors that caused the failure in the Bowline-on-the-Bight, or BotB. This was achieved and we could generate failures almost 100% of the time. This test is written up in the last blog post.
Today’s testing was all about trying to get a failure in a normal use environment with normal conditions. All the tests we did were on knots that has been tied, dressed and set as we would and have done thousands of times underground. We were not wanting to tie sloppy knots, we wanted to see if it would fail when it was done well.
For every test of every rope in every combination of orientations we tried, so long as the cowstail was attached through both loops of the knot there were no failures. This was as expected and ties in with the best practice advice that has been taught for years with the use of the BotB – ALWAYS CLIP BOTH LOOPS.
For tests carried out where we dropped onto a single loop – the one formed from the traverse line or stopper knot, we could also generate no failures. However this is outside the intended use of the knot so little time was spent investigating that scenario.
When connected to the Bowline-on-the-Bight with a cowstail attached to the single loop formed by the pitch rope we were able to generate failures in knots that were tied and dressed correctly that had been hand tightened or on occasion body weight tightened.
Below are a pair of images showing slip through the knot. Note the blue mark.
A second set of test images:
The Bowline-on-the-Bight can fail when you are clipped into a single loop and the knot is dressed correctly and tightened. The failures we generated included ones where we both agreed that we had tied a perfectly acceptable BotB before testing.
Although we can identify many modes in which we could not get a failure to occur, the fact that one can occur in normal* use is very worrying.
* normal use if you only use one loop to attach your cowstails as is against the best advice – always clip through both loops!
So now what?
Cavers should draw their own conclusions from these tests or indeed conduct their own perhaps.
I believe that it is still appropriate to teach the Bowline-on-the-Bight as one of the standard knots for caving alongside the information about how to use it safely and the consequence of misuse.
I will copy this information to the British Caving Association for review. It is not my place to advise on caving policy for the UK.
I have been offered the chance to use a rope tester to look at potential replacements for the BotB. The test will give us a chance to see how a replacement compares with the existing methods in terms of strength and durability.
The French’s preferred option – the Fusion Knot, which has also been called the Karash Knot, is high on the list of contenders but I feel that a similar knot to the BotB would be more easily absorbed by the caving community. Both myself and Jez think a closer look at the Double-Bowline tied on the Bight may give a very good alternative. We’re calling it a D-BoB, or Double Bowline-on-the-Bight, until we can establish its correct name.