The following article details digs and exploratory work that I have been involved with Tony
Donovan and Roy Morgan over the past year.
Crowbar Hole, NGR SN 9010 1464
I am quite sure that this cave on Pant Mawr would have disappeared into obscurity had it not been for the efforts of Tony Donovan and Roy Morgan. When Chris Crowley, Trevor Pritchard and myself dug into this cave on 17th November 1990, I subsequently wrote, "All in all, this cave is not a contender for a way into the Pant Mawr master system."
Well, as I write this in Autumn 2006, my initial pessimism may be proved wrong. A year or so ago, Tony unblocked the collapsed 8 metres deep entrance shaft and installed scaffolding. In 1990, I reported a further 8 metres of rift dropping down from the base of the shaft which was too tight to enter. Now, in 2006, Tony and Roy have after much effort enlarged the rift and at the bottom and broken into a short section of phreatic type passage trending in a westerly direction. This passage quickly ends with a small but perfectly formed aven heading back to the surface.
From the base of the shaft, the passage appears to carry on in the other direction, i.e. to the South East. However, a boulder choke formed at the base of the entrance shaft blocks an easy entrance into this. As you can imagine, Tony and Roy are doing their utmost to engineer a route through this.
On a positive note, this cave does possess a definite outward summer draught and it is hoped that even if the mythical Pant Mawr Master System is not found on this occasion, a reasonable bit of cave may be discovered.
Stop press. On the 22nd October 2006, the boulder choke was passed to gain a small passage beyond which takes a small stream and the draught. Further digging will probably be required to make progress along this.
Rusty Horse Shoe Dig - Black Mountain
This cave is situated approximately 500 metres to the north west of the cave Sink y Giedd, one of the main sinks for Dan yr Ogof.
It can be seen that much effort has been put in here in the past. An oil drum entrance drops onto the top of a free-climbable 4 metre deep shaft, most of which looks as if it has been blasted. At the base of the shaft is a tight dog-leg passage, which then leads to a short section of horizontal passage with a fractured left hand wall and a
boulder choked scaffolded right hand wall. This is the current dig terminus.
Recent work in the cave in 2006 has involved digging in a bypass to the dog-leg passage. Prior to this, at least six men were required to bring spoil to the surface via the contortions of the dog-leg passage. Now a reasonably straight pull from the dig face means that only four men are now required. As well as this, spoil is coming out with much greater ease.
Subsequent to getting the dog-leg bypass, work Adrian Paniwnyk in a phreatic tube near the has now begun to enlarge and shore a way towards a stream which can be heard a short distance ahead. This presumably is the stream that sinks on the surface close to the entrance. This stream has not been traced to Dan yr Ogof, but it is assumed, due to its
proximity to sights which have been traced, such as Sink y Giedd, that the water sinking at Rusty Horse Shoe also goes to Dan yr Ogof.
On the two times I have visited the cave, it has been draughting strongly. Also, Rusty Horse Shoe lies within the Dowlais Beds, as does Dan yr Ogof. Sinkly Giedd, being further to the south, lies within the upper Penwyllt Beds. Thus a greater vertical distance will have to be covered to gain the underlying Dowlais Beds. This does not mean that a lot of effort will be required, but it is hoped that even if the hypothetical "Giedd" system is not found, a reasonable bit of cave will be revealed.
New Quarry Cave
A new cave has been exposed by quarrying activities. At present, it is about 90 metres long, ending in a boulder choke but likely to get substantially smal er when they start quarrying into it. Obviously there is no official access to this site access to this site.
The overall trend of the passage is to the South East with crawling size strike passages and a larger down-dip passage. The cave is situated near and above other known caves which are situated at the base of the limestone / lower limestone shales. It is interesting to note that the alignment of the cave is similar to earlier caves found in the quarry but now totally quarried away. Most of the passage found in this new section of cave seems to be phreatic in origin, but the down dip passage seems to show vadose modification (see photographs). The cave possesses a few formations and it is interesting to note that many of these are translucent and ice-like. Maybe this is due to leaching out of minerals with depth?
The new cave is almost certainly related to a large section of passage entered a year ago, running parallel with the quarry bench, i.e. NE-SW. This has now been quarried away but a few remnants of it can be seen as you approach the new cave along the quarry bench from the SW.
It should be noted that work to remove the cave has already begun, with the quarrying away of some of the bench near the entrance necessitating a difficult traverse. Presumably in the near future the entrance will be left "hanging" half way up the cliff face. However, hopefully it is not all "doom and gloom" for this cave. The down dip sections of the cave puts the known end of the cave beyond the quarry boundary fence and it is very unlikely that it will be extended further as this would mean the quarry could be seen from the south. Providing that the way in has not been totally obscured, access should be gained if and when the quarry stops operating.
Ogof Pig Melin (Yellow Beak Cave), NGR SO 2625 0800
The Ogof Pig Melin (OPM) caves are situated in a small quarry to the south of Blaenavon adjacent to the A4043. Rifts in
this quarry prior to digging all draughted strongly and it is for this reason that Roy Morgan turned his attention to th
is site. By far, the most extensive of the caves is OPM 4 (see survey). There were a few false starts here, as this was
the last site in the quarry to be dug. OPM 3, although not marked on the survey is slightly to the north of OPM 1. It h
as received a bit of digging attention but does not really get underground at present.
The first site to be dug, OPM 1, starts as a rift but ends in a pot with a draughting choke at the bottom. This was only abandoned by Tony when it was deemed too dangerous to dig and having looked at it, I agree with him! In order to bypass this, a surface dig was started, OPM 2, but this was again abandoned when the rift at the bottom became too tight and loose.
Fortunately, digging OPM 4 has proved more fruitful. After enlarging a rift for some distance, a chamber was gained. Loo
king at the survey, it is probable that OPM 1 connects through here but of course through the suicidal boulder choke. Fr
om the chamber, a dig down and then back up has gained a larger chamber or passage. It is really at this point that one of the cave's more unnerving features begins to make its presence felt, i.e. a preponderance of break down blocks and blocks handing from the roof and ceiling which look as if they might break down on top of you! It is in this chamber that Tony, in an attempt to sort out what he cal s the large blocks "hanging from the roof like Christmas decorations", installed some serious bits of steel work.
At the back of this chamber, an excavated crawl gained a way into another passage heading south, yielding the largest chamber within the cave. This passage again would be very nice indeed, were it not for the large quantities of hanging death within it. However, draught tests seemed to indicate that it was heading out of the surface and it ends in the obligatory suicidal choke.
It is at this point that the way on into the hil appeared to be lost. However, on a very cold day over Christmas 2005,
Roy located the draught coming out of a very smal rift opposite the squeeze up into the southerly trending passage. Dutifully, a way along the rift was enlarged to eventual y gain a small stream passage, which initially raised enthusiasm a good deal. Sadly, this passage is bedevilled with the same problem the rest of the cave suffers from, i.e. Large amounts of hanging death. I have not been right to the end, but Tony reports that the terminal choke again contributed to stability problems and not aided cave formation - this dolomitisation gets more prevalent as you move east.
On a positive note, the draught at the end of the cave is as strong as ever and the cave lies between the two theorised
continuations of Ogof Draenen, Rifleman's stream way and Luck of the Draw passage. Sadly however, it looks like the dig within this cave has been abandoned at present.
Ogof Nant Rhin
The survey of the cave down from the relatively new top entrance to the Aven d'Oznog pitch has been completed and drawn up by Roy Morgan. Looking at the survey, it looks very tight. Nant Hafod pot may be associated with the Kerplunk area of Nant Rhin. It should be noted that the bottom entrance of Nant Rhin is in a pretty poor state after a runaway lorry on the Heads of the Valley road crashed down on top of it!