REOPENING THE CAVERN - IREBY FELL

T.Reynolds

I. General History

Introduction

The Northern Pennine Club can honour themselves as being the first club to make any real constructive effort in reopening the cavern, since the entrance was blocked in 1954. Previous unsuccessful attempts had been made; much to the disappointment of many potholers, who regarded the cavern as being a major cave in a strategic area, and warranting more consideration, it was therefore proposed by various members, including myself, that the situation needed rectifying. Although some members were not in full support of the project, their argument being that the cavern had already been discovered and explored, we carried out operations to the full and with a certain degree of success.

There are many reasons for supporting a scheme of this nature, one being that the details can be steadily worked out over a long period, and time can be allowed for thought on a scientific line, as against the rushed burrowing of an anticipated glory which never seems to come. Before running ahead with digging we realised that a great deal of thought and study would be necessary, if we were going to attain the success we sought.

The entrance to the cavern lies in a stream bed which under normal conditions is dry. The bulk of the water is taken underground by two inlets marked as higher and lower on the diagram. After sinking in the stream bed about one hundred feet away from the cave entrance, the higher inlet comes out over the first pitch. The lower inlet sinks about twenty feet away from the entrance, and surmising from examination of a survey in Cave Science, 1949, we assume it comes out over the second pitch. In 1954, an overnight deluge flooded the cave and washed in mud and boulders from the banks of the surrounding entrance with the result that it blocked the first pitch. The water from the higher inlet could not be drained away and consequently a large pool formed over the blocked pitch, entirely submerging it, and preventing any attempts at clearance. To remove the pool a dam was constructed outside the cave and above the inlets, but to our amazement, the reverse happened for instead of the water level dropping it rose. This was the whole key to our problem. Working on the theory of the whole pitch being full of water, we would expect the level of the pool to drop, and then compensate as the higher inlet increased in volume. In other words, if the obstruction was further down the pitch as it had always been thought to be by earlier excavators, the pool level would have remained unaltered, no matter how much we diverted the stream. This was not so. The pool changed its level with the increase of water from the higher inlet. The pool's independence from any other influences suggested that the obstruction was at the top of the first pitch and quite within our reach.

Finding that the obstruction was only a few feet from the entrance, we were encouraged to go ahead with operations. Our party of cave diggers and "lookers on", ready to be assisted and encouraged by Bert Tucker, who was on the first party to explore the Cavern way back in the dark days when Alum Pot was a clint, were eager to put theory into practice, and by mid-June a fleet of Austin vans were regularly departing from the cottage.

With the aid of a flook pipe, we were able to drop the level of the pool by about five per cent of its volume over a period of a day provided the weather was stable. But this was not sufficient and after a mid-week rainfall the whole cave flooded, making the situation quite impossible for further work on similar lines. More vigourous steps had to be taken.

At about the beginning of August, operation "Water Bucket" came into being. A mining company was formed and well-known club Pharoes recruited or forced able-bodied probationary members into the task of donkeying for them, and many a despondent newcomer was whipped into hauling the best cottage bread bin up from the depths below. With furious determination and maybe the aid of gravity, the bin was hurtled back again to be filled from an intermediate settling tank by the "experts". An antique treasure of the past in the form of a favourite Pennine bathtub was used for this purpose and possibly other things too. Thus developed the ponderous sequence of events which carried the water to the surface: pool to coal bucket, coal bucket to coal scuttle, coal scuttle to bath tub, bath tub to bread bin, and then on reaching the surface an empty bread bin to be emptied and sent underground again to repeat operations.

Obviously other methods had to be used, and a spontaneous, unconscious act of Albert Wilson, rather than a considered rational act of judgement, now altered the sequence of events. Whilst Albert was probing about in the pool with a crowbar, he discovered by accident the long sought outlet of the pool. All efforts were concentrated on this point, and to our satisfaction the level of the pool dropped. Finding more places where the water could be drained we succeeded in appreciably reducing its volume. Although we had succeeded in draining off most of the water, we were still hampered by a small trickle from the higher inlet, which was enough to turn the whole place into a slimy mudbath and make further work almost impossible. After wallowing about like hippos at the London zoo, we decided to erect an aqueduct to carry the water over the digging area and away down one of our newly found drains. This took the shape of a length of flook pipe supported by several short slings belayed to the roof.

Concentrated digging was now able to commence and many eager diggers from Thackthwaite Beck to Fountains Fell came in their numbers to support a project which before they had thought quite worthless. After three or four weekends of hard work the digging team broke through to the top of the first pitch and with the aid of corrugated iron sheets and oil drums were able to make the entrance reasonably safe, ready for a party to descend.

The Cavern was now reopened. We had achieved what we had aimed for which was (a) to remove the pool at the top of the first pitch, (b) to remove the blockage which had caused the pool and had barred access and, (c) to remove the doubt in people's minds as to whether our efforts were warranted.

II Details of the successful attempt

A Wilson

In the summer of 1961 it was decided to investigate the situation at Ireby Fell Cavern where a large flood in 1953 had completely blocked the passage quite near to the entrance.

First inspections revealed nothing to raise any hope of a solution to the problem. The entrance passage leads down a steep boulder slope to a large sump where the original passage had been, and no visible outlet for the water was located. The sump measured about 20 ft. long, four feet wide and 15 feet deep and with no outlet this was quite an amount of water. Added to this was the fact that two inlets streams were feeding the pool so that any baling would have to be done at a very fast rate. One experiment was obvious, however, before any baling was begun - to dam the surface stream and so cut down the water from one of the inlets. In this way we could determine the rate at which the water drained through the blockage.

Efforts in this direction commenced immediately and a large dam was constructed across the surface stream bed. The water was successfully stopped on the surface but on inspecting the pool level it was clear that the water level had risen quite considerably. This was very disconcerting at first but we deduced that the dam must be over a sink which led to the inlet below and that further sinks in the bed which originally by-passed the blockage were now being starved. The dam was thus broken down and work finished for the weekend.

During the week, surveys were studied and the nature of the blockage was analysed.

The long boulder slope had originally led to a lower section of passage before coming to a 20 ft. pitch. As the lower sections were of reasonable proportions, it could be assumed that the pitch was not blocked for the whole of its depth and that the whole boulder slope had moved with the stream to block the lower section of passage. Measurements to the head of the inlet passage indicated that there was at least a six foot depth of rubble above the constriction.

The first major work then, was to cut off the water from the main inlet and divert it down one of the other sinks in the surface stream. This was made possible by the use of 6 in. diameter rubber hose, which with suitable end sealing could accommodate the whole of the surface stream so making the main inlet dry. No great difference in level showed itself so that baling had to commence. All the water had to be lifted about 40 ft. to the surface to find a sink that would not return to the pool. An overhead cable was installed to take buckets to the surface but a full day's work served only to reduce the level about five feet. No signs were seen which would help to ease the difficulty.

During the following week floods had taken their toll and the water marks on the wall showed that the pool had risen about 30 feet during the week. However, it was now back to its normal level and there were indications that the water must be draining away in some sections of the pool at a greater rate than in others. It was thus decided to dig in one possible place to try and get a porous layer in order to get rid of the water that way. A hole was dug some four feet deep and as expected an increased drain off was observed. This was the most important discovery to date and eventually proved the key to the solution. A channel was cut into the hole and the water left to drain during the week.

Once again severe storms during the week had brought down tons and tons of rubble from the surface and had completely blocked our original water sink so that again a head of about forty feet of water had been produced. Thus several weekends had to be spent in making sure that further debris would not flow into the cave itself and to this end several walls were built across the stream bed and a new course constructed so that the cave entrance did not get the full force of the stream.

With drier surface weather, efforts were redoubled and the sink was dug out to a depth of about 8 feet to a good porous layer. The smaller inlet stream was then piped to a sink inside the cave which did not connect with the pool and the large inlet was piped over the pool into the newly dug sink. In this way it was possible to drain the pool completely in about 15 minutes by continuous baling.

At last then, we were able to set foot on the rubble itself and commence digging a shaft over the blockage. Good progress was made but a great deal of time was wasted in sawing off stemples to hold back the rubble. The five foot depth of rubble proved to be quite inaccurate however and attempts at a breakthrough had to be abandoned once again until the following week.

Digging was reasonably easy and it was clear that the soil and peat in the rubble was responsible for the waterproofing. The shaft eventually hit boulders and the small amount of water in the shaft drained away. Another foot and the breakthrough was made. The stones apparently fell about fifteen feet before going over the edge of the next pitch. After a further hour there was enough room to get through and inspect. A very dangerous boulder slope led to the head of the pitch which had no visible belay.

Again work had to be abandoned for the week and the following weekend had to be spent in making the boulder slope safe and also fixing oil drums in the excavated shafts to stop any further earth movements.

Finally on the 19th November, the way was open for the first descent. Rawlbolts were inserted above the first two pitches and at a later date a third may be inserted for the third pitch.


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