Pit Props Passage Stopes - Phil Wolstenholme
This trip was mainly to follow up observations on a previous trip by Wayne, Boyd Potts and myself into the stopes, and to try and tie-up what we'd seen with the limited survey data currently available. Also to try and push the site a bit and see if the so-called 'no connections' theory was actually true. We knew Nigel Ball has done exploring in here in the past, amongst others, including TSG members way back, but very little is known about the explorations. It's possible documentation exists in the library, so I hope to check through soon. Ann and Roy kindly agreed to accompany us, which made things much easier and gave us more exploration options.
Water levels were reasonable, and the temperature not at the usual infertility-inducing level, so we hauled off quickly down the Far Canal, swung into the branch passage past the deep holes and into the main stope. The only way we knew of that leads upwards is via the muddy ore-chute, and so we all scrambled up to the top using the grotty in-situ handline. Roy had a quick look in the the chamber that leads to the top, whilst Wayne and I free-clambered dangerously up a very loose and muddy hole in the roof of the chute in order to check out the stopes above, and try and establish the location within the survey of a slabbed-over section in the roof so we can ascertain possible access to workings above. There is also an old TSG dig in the floor of the next chamber up, which is down through an old phreatic tube heading back to stream level, but it's far too rotten and dangerous to re-explore without substantial renovations.
We made a simple centre-line survey of the upper level cut through the pipes, and noted smaller ore-chutes that drop back down into the main one. At the far end of the level, about 15m along, a hole in the wall drops down into a larger egg-shaped stope in a worked-out pipe which ultimately connects back to the base of the main ore-chute, with a steep slope of loose rocks and gravel being the 'way in'. I slithered roughly down first, and after we measured the distance, Wayne followed me down - even more roughly! A rock he'd used for support proved to be unattached to anything in reality, and he and the rock came crashing down far faster and less delicately than he'd anticipated, banging his elbow badly in the process. The rock then slammed into my leg, but as I wear shin-pads, no problems!
Having roughly measured the stope and establishing that we could indeed get out of the bottom connection (Roy's light was a huge relief), I then crawled off around a sharp corner to check out any leads. Surprisingly, there was a wide and smooth water-worn passage coming steeply downwards toward me, and which was choked with two TV-sized boulders a couple of metres above my entry point. Downslope, the passage was open, and climbing over other boulders I dropped down a few metres to a sharp right turn, with holes between the boulders showing a gravel floor a couple of metres lower. I went round the corner and was amazed to find a rather large natural water-worn bedding-chamber of roughly rectagular plan, about 25m X 10m, and about 1.5 metres high at the highest point, but with an average height of 0.5 metres. The lower half of the cave was full of smooth, dryish mud, in 'mountain' formations.
Crawling around showed that the walls of the chamber descended well below the mud levels, and if the mud were not there, it would probably be possible to walk around, rather than crawl, but the whole chamber is very well-ventilated and fresh. A constant drone or rumble is present, being either the Bung, or the streamway underneath cascading through to the Bung base. All theory at present. But I quite like 'The Boiler Room' as a name for the chamber, as that's exactly what it sounds like.
The roof of the chamber is mostly smooth from water-wear, so it probably drained the phreatic passage that leads down into it, before somehow/where connecting to the original (pre-mining) streamway. Two small phreatic tubes/avens in the roof near the entrance are body tight and not looked at yet. Mining and the blasting of the branch canal has obviously changed the original streamway connections from the phreatic passage beyond comprehension at present, but this chamber is completely untouched by the miners - no mineralisation, no pickwork, no shotholes - all completely natural. The mud may cover a whole heap of miner's deads, but it doesn't look that way. Its absence from any documentation I've seen is baffling, so we're asking around to see who knows about it.
We've made a simple survey, and Wayne can confirm more accurate dimensions later, but a water-worn natural chamber of this size, placed midway between the Bung and Pit Props, and probably close to the western extremity of Block Hall, is both exciting and baffling, to me anyway. And why we're the first to report it is even more baffling...