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Gour Rift Dig

An account of this dig in Cuthbert’s by Dave Irwin.

During the summer of 1972, through to the spring of 1973, the Sunday Morning Digging Team attacked the end of the Gour Rift in an abortive attempt to excavate a continuation of the Gour Rift.

For years, the end of the rift looked a tempting site for an attack.  In the early days of the exploration of St. Cuthbert’s, the end had been investigated and the Bank Grill entered, but this tight ascending passage gradually closed down.  In 1957, the sump was passed by Balcombe and Coase only to discover the further sump that was destined to become Sump 1 - the original sump being then known as the Duck. In 1966, John Cornwell made the first attempt that seriously attracted cavers to the end of the Gour Rift, but after a short series of digging sessions, the site was abandoned.  At about the same time the Taylor brothers made an attempt at the still un-entered hole at the top of the aven above the Great Gour in an attempt to see if there was a high level passage over the top of the Gour Rift.

Then, in 1966, the Tuesday Evening Digging Team came into existence (Turner; Irwin; Craig; Woodward; Webster and several others) who bashed the Dining Room dig for nearly three years and excavated a passage over 150 feet long that has how been proved to be the upstream end of the Whitsun Series.  Then came the major breakthrough - almost by accident.  By chance, the terminal sump of St. Cuthbert’s was found to be empty of water in the autumn drought of 1969.  Secret digging sessions (up to five in a week!) were made by Bennett; Craig et. al. and were rewarded with the discovery of Cuthbert’s II.  A serious attempt to explore all the high level passages of two was made by Bennett et al. in the following few years, together with an attempt to pass Sump 2.  All prospects of continuing the cave in Two diminished.

During the same period as the Gour Rift Dig, then S.M.C.C. dug at a point just downstream of Sump 1 at a point where the water was known to soak away in dry weather.  They reached a depth of about fifteen feet before giving up.

At the same time, the S.M.D.T. attacked the end of Gour Rift.  The early digging sessions were limited to the left hand wall.  It was here that Cornwell had dug in under an overhang that gave the appearance of another passage running off the line of the rift by about fifteen degrees to the east.  The other point that was of interest was the extreme end of the rift, where the tops of two phreatic arches could be seen.  These had been modified by two chemical persuasion attempts a few years earlier (Irwin; Craig and Searle in 1968 and Turner and Bennett in 1970) in an attempt to see clearly up into the rift down which came the Bank Grill water.  However, it became clear that a serious digging attempt had to be made and so the dig became a bail-and-dig session.  The whole floor was lowered and of course, the lower the floor became, the larger the pool of water that had to be bailed the following week in order that digging could be resumed.  To prevent the water from flowing back through the Duck, a small concrete dam was constructed.  The construction of this dam eased the bailing operation considerably, as the pool now needed about an hour and a half to bail. As the fill began to be removed, large lumps of stal gouring were uncovered.  At first it was thought that these were the remains of a series of descending gours that continued on from the abrupt end of the series in the Gour Rift. However, this was not so and they were, in fact, isolated lumps which had been deposited in the infill.  At the end, the phreatic arches were dug into and it was found that they were merely the top of a four foot deep by foot wide phreatic hollow or pocket.  Undeterred, the diggers continued lower to a depth of about nine feet.  It was at this depth that the greatest blow occurred.  A rim of rock was uncovered which ran round the extreme end of the rift forming the top of a pothole.  This was probed with iron rods to a depth of between five and six feet by a series of probes that gradually increased the angle of attack so that an impression of the shape of the wall under the infill could be obtained. Hopes of any sign of undercutting of the wall soon faded when it was found that the walls were smooth and vertical. At this time, the digging sessions were becoming more of a bailing operation than a dig.  The bailing time went up to about two hours. and digging time was correspondingly reduced.

To assist the bailing, several ideas were submitted, but the most practical idea came from John Knops in the form of a water wheel.  However, in practice, difficulties arose in the form of binding bearings and other mechanical problems.  During this time, large quantities of wood were taken down the cave to shore up the right hand wall of infill to replace the galvanised sheeting that held back the wall until the diggers undercut it and the inevitable happened.  When the dig had been taken to its lowest point attention was transferred to the right hand side, under the breccia in which is formed the Bank Grill pothole.  The diggers dug in under the breccia, only to find that a floor existed that sloped downwards, but back towards the Duck.  Probing at the Duck itself revealed that the small arch which forms the Duck is, in fact, the top of a six foot wide arch, largely buried in the infill.

However, for all the problems, we have learned a little about the end of the rift that has attracted so much attention in the past before work on the Burrington Atlas and on other activities - not least the advent of winter combined to bring the dig to a grinding halt early in 1973.  Anyone wishing to continue where we left off is very welcome, but some form of pumping device is essential to probe further than the S.M.D.T. were able to do.  Perhaps after all the work that has been carried out at the end of St. Cuthbert’s, the real way on will be found at the bottom of the lake!

For the record, the regular diggers at the Gour Rift were Doug Stuckey; Dave Irwin; Dave Turner; Chris Williams; John Rees; John Knops and many others including tourist trippers.

( A sketch of the dig will be found on the next page.)