Site to assist in the management of the North Wales Mine Inspections for the LCMLA
There’s been a few updates sent out to users of Rhiwbach, Wrysgan and Bwlch y Plwm. Would be worth checking with whoever you’re working for if you’re heading underground with groups.
We’re also looking to get a working party up to Rhiwbach Friday afternoon. Get in touch if you’re free to help carry some heavy stuff up to the mine! Did I sell that….
Gethin
Sounds like there’s been a small (but worth taking note of!) rock-fall above the traverse on floor 3 of the mine:
Hi Gethin,
Picture attached of a recent rock fall in Wrysgan. Abseil stance at the end of the L3 traverse, after the island!
Obvious missing bits from the roof but I couldn’t see anything hanging….waiting to drop!!
Couple of pieces managed to make it down to L2 at the bottom of the pitch!!
Regards
Jim.
Meeting: 25th January 2017
10am-1pm Oaklands OEC
Following last years gathering it was suggested we try to arrange an annual get together for those using the mines in North Wales. The aim of the meeting is to try and discus a variety of topics such as access, bolting, radon and this years round of mine inspections.
Details are also available here: www.northwalesmines.worpress.com
Rough Agenda
I’d hope we could rattle through this lot in a few hours, hope you can make it. Directions to Oaklands can be found here: http://oaklands-centre.co.uk/index.php/contact-us/how-to-find-us/
Gethin
22 January 2017
How would people feel about getting together for a users chat, similar to the event we ran last year?
Topics would include
I’m trying to pull a date together so feel free to let us know when you’d be available and we’ll pick a date when most are free: http://doodle.com/poll/x6vgttcffyub9feg
Meeting to be held at Oaklands starting at 10am, with a view to possibly doing some heavy lifting in the afternoon up to Rhiwbach!!
Gethin
Hi all, there’s been some updates in how staff may need to access the boat in Rhiwbach. If you’re working in the mine it’s worth having a chat with the provider you’re working for.
Gethin
There’s been a bit of work done clearing the wall in the boating chamber. Consult whoever you’re working for for more details
The first set of Radon reports are now available to download. Get in touch with whoever you’re working for to get a look at the reports.
It may also be useful to have a read of the BCAs advice on radon underground: Click here
Radon monitors have arrived and will be placed over the next few days. Please do get in touch if you’re around and fancy getting out of the sun for a few hours to place them!
Monitors are to be placed in designated sites, below is a list of whats going where. They will be in place for 4 weeks then sent off for analysis. Once they’re back the reports will be added to the mine inspection reports folders online.
If you spot any of the monitors when underground over the next few weeks please do not fiddle with them. They are sealed in plastic bags and should not be opened or moved. May be worth briefing your groups…
Gethin
Radon Tests Sites for North Wales Mines
Here’s a few images/warnings issued over the years that still stand for some sites. These images have dropped down to the bottom of the news feed on the site so I thought I’d add them again and stick them to the top of the updates feed.
Rhiwbach Brow
Here’s a photo of the brow taken after the cracks were originally painted, this image can be used to compare any changes
Rhiwbach Entrance Adit
Picture of the entrance which has seen some vegetation’s slippage over the Winter of 2015-16
Rhiwbach Top Entrance
Photo following clearing some loose rock at the exit of the mine
Wrysgan Slab
Route passed the fallen (eased) block between floors 4 & 5 in Wrysgan
Wrysgan Roof
Section of roof which pealed away in 2014. Photo can be used to compare changes
On the 18th of March 2016 the majority of the anchors in Rhiwbach mine were inspected and tested. This work was requested and funded by Go Below Underground Adventures Ltd who engaged Pete Knight to undertake the testing.
The anchors were tested to 6kN for 15 seconds using a Hilti HAT-28 anchor tester with a current calibration certificate. All anchors that passed (showed no movement, deformation or rock failure) were marked with a green cable tie. Anchors that were deemed to have failed (moved, deformed or detached from the rock) and could not be removed from the mine were marked with several red cable ties. No failed anchors remain attached to fixed rigging. Unmarked anchors were installed after the 18th March and remain untested.
There are no plans to retest any anchors on a regular basis as it is a concern that the resin bond may be damaged by regular high load testing. No Petzl P38 Longlife anchors were tested in Rhiwbach.
Tyrolean Area
All anchors were tested in this area. One Petzl Collinox anchor was removed from the wall under the test load. It detached with a section of slate that showed a hidden area of quartz weakness. This anchor was not replaced as it was immediately adjacent to another which passed the test.
Pool Traverse in next chamber
The final anchor in the chain appeared to have been hammered into the rock to prevent use. It could not be tested or removed but was tagged as a failure. All remaining anchors passed.
Climb and Traverse to Abseils
All anchors passed.
Waterfall Climb
The lowest of the Collinox anchors had a small amount of spalling under test. It was tested to 10kN as a precaution and passed. This anchor should be checked regularly by users to identify any further rock degradation.
Airshaft
3 Collinox anchors failed in this section of the mine. One was removed completely but the other 2 are awaiting removal/destruction but have been tagged as failures and removed from the rigging.
1 Collinox was removed from the rock along with its resin. The hole appeared to have not been cleaned prior to installation. A second Collinox was removed because the section of rock it was in split apart. The third anchor was another Collinox, which began extracting with its resin. Replacement anchors have been installed already but will not have been tested.
Summary
The testing does not diminish or remove the important requirement for all users to inspect the anchor and overall safety system on each and every use. The nature of the rock and the type of use these anchors receive may mean that an anchor can become suspect or even fail in the future. This can happen without warning and cannot be predicted by this testing. All fixed rigging attached to the tested anchors remains the responsibility of the installing organisation and all users are reminded to inspect for safety prior to each and every use.
Peter Knight 3/5/2016
