Merlin's/Gimli's Dream/Carlswark - Phil Wolstenholme

Monday, 19 June, 2017

Present: Alex Crow, Phil Wolstenholme

This trip was a bit short-notice, to collect dye-detectors placed a fortnight or so ago by Rob Eavis, and was essentially partly a gamble again, as Alex had never been to Merlin's before (and possibly not Carlswark either), and I had only been to Merlin's/Gimli's Dream once before - and although I've visited Carlswark several times, I've always been with someone who know the route well, and never really had to pay that much attention to where we were going. Or had I? I'd also attempted the Eyam Dale Shaft/Gimli's Dream connection ages ago with Jess E and Martyn, but we gave up, unable to find the way through. So the prospect of a through-trip both ways, with specific things to do, and get back in time for supper was quite a challenge, given the high potential for confusion - especially in tropical jungle conditions.

The plan was to do Merlin's, have a look at the connection, but give up quick if we couldn't find it, then bomb back out, and rig Eyam Dale Shaft, drop that, etc. The trip down the internal shaft was painless, so we dropped our harnesses there and crawled to the streamway first - which whilst not flowing, was definitely sumping Sump 1, so not a chance of picking up the detector at Sump 3. The detector was sat on a ledge of mud, so the levels must have been much higher after Rob placed them, as he'd never have got to 3 otherwise. I took a temp and TDS reading with my spiffy new meter just in case that might be useful later, and we then set off for the flat-out crawl into Gimli's Dream, though I took the more cavalier option of the head-first 90° bend inwards rather than feet first. I have no idea what Alex did as you can barely lift your head for a while. Eventually we got to a section I recognised - the famous `C9C Mud Incident Chamber`, and we decided to have a go at the choke.

Rob had told Alex to follow the draught, and we did that quite successfully for a while until we got to the middle, where it gets complicated, both in terms of draught and possible ways on. We tried a downward route that ended in a metre-diameter phreatic tube blocked with sediment and gravel - obviously not the way on - at present! We also noted another large-scale semi-filled phreatic tube heading back under the main floor toward the crawl in - anyone know where that goes? By this time we were pretty committed, but not really there, so I had to get the sniffer-dog mode out and finally got to a taped section I recognised - from the other side! So I knew we'd done it, I just had to remember which tiny squeezes got us out of the chambers with spoil, and into the shaft itself. Again, intuition and draughts eventually got us there, but by this time it was nearly 9pm, and we were running out of time, as our callout was 11. So we decided to abandon the return trip, and just get the detector (in Big Dig Passage of all places!), and leg it out via the Gin Entrance, which I knew I could find, and then go back to Merlin's, abseil down the shaft to get our harnesses (erm...oops!) and then de-rig and go home. But first I had to remember how to get to Big Dig, and though it's not difficult, and I'd tried to remember the survey, we did have to check it once or twice to be certain.

The main Big Dig passage was predictably a third-full with water, and by the time we got to the timbers, there was less than a foot of air-space, so pretty much flat-out and gasping was the style here - the only consolation being that most of the mud got washed off my suit. Also the main streamway passage was flowing quite strongly from Shag's Sump, which was weird, as the water was static in Merlin's - I guess more water must come in elsewhere beyond here? The detector was at an inlet beyond the rift/Hole in the Road section, and amazingly, we got there easily. I took another water reading, and we swiftly set off for salvation, remembering the tricky squeeze warned about in COPD. Eyam Passage was impressive again, though tediously longer than usual! Once back out in the light (and heat), the cliff-top path to the road and then Merlin's was a doddle, and we climbed back up into the jungle for the now interesting harness-retrieval job. So the short story there is that it's actually a pretty easy free-climb down the shaft with a rope to wrap down your back! But don't tell anyone I did that. Once me and the harnesses were back up safely, we swiftly legged it back out into the steaming evening again for the final time. It was quite a strenous trip, given the amount we had to cover in the time, with a lot of mental work to make sure we didn't get lost, but very satisfying to get most of the job done, and find the route through.