site 3916

3916: BigMat Calf Hole
Hornedo 30T 448564 4800273 (Datum: ETRS89. Accuracy code: A) Altitude 155m
Length included in Torca la Vaca (site 2889)
Area position : Site entrance in context : Logbook search

Updated 21st October 2013; 6th March, 26th May, 9th, 12th October, 5th December 2014; 2nd January, 23rd February, 23rd May, 5th, 17th October 2015; 4^th May, 25th October 2016; 30th June 2018

   The steel mesh cover the BigMat Calf Hole entrance must be over the hole at all times. Goats knock stones from the wall and there has been at least one instance when a hefty rock was only prevented from falling onto a caver below when it was stopped, mid-bounce, by a well placed foot. If the animals are about, close the lid as each person descends and ascends the entrance tube.

   BigMat Calf Hole is the "Vaca Back Door" and the preferred entrance for explorations south of the duck/sump in the Torca la Vaca System. The entrance lies at the edge of a field approached off the first bend on a track from the farmhouse. Vehicles should not block the road and must leave room for milk tankers to pass at any time of the day. It may be possible to park in the farmyard, with permission.
   A 2m high stone wall that held back the spoil removed from the dig has now slumped. The entrance has a concrete surround with a grid and an almost vertical, 60cm wide drainage tube (with holes cut into the side) drops 3m down into a rift. The lid should cover the hole at all times to prevent animals and rocks falling down. The field is used by livestock.
    The route is 5m down between scaffold tubes to a crawl on the left through another tube which connects through to a loose boulder slope and a permanently rigged 12m pitch down into a rift. Through to the northeast is another permanently rigged 5m climb down that drops down onto the Wasdale Screes and the remainder of Torca la Vaca. This route removes the need to negotiate the duck or dive at Lake Bassenthwaite and puts the caver well south of Scafell Aven.
    Two videos show the complicated route through to the Walking on Eggshells passage in Torca la Vaca. (See below)

The site was noticed a couple of days after the successful molephone location at Wasdale Screes in Torca la Vaca which put the underground molephone station directly under a large block on the track skirting a large and deep depression, full of eucalyptus trees. The block appeared to be at the side of a joint, the direction of which lined up nicely with the underground rift. When a quick examination and some cursory digs along the line in the depression failed to reveal any promise (just sandstone boulders and soil), the north side of the track, into the field, was inspected. A shallow depression with one tiny piece of visible limestone was seen and, with nothing else to dig against, an excavation was started here. By the end of the summer 2013 campaign and after some 14 visits, the site was over 8m deep, shored up with scaffold poles and planks with an encouraging draught and underground features that gave hope for a connection with Torca la Vaca.

   It was noticed in February 2014 that the shaft top had slumped. The hole was covered with branches to wait for remedial work and further excavation.
   After 10 digging sessions that Easter, the soft sludge that had completely filled the hole was finally removed. This left the hole more or less in the state it was at the end of the previous summer except that much more shoring was deployed to keep back the rest of sediment. The site was still draughting.

   The summer 2014 campaign started with more digging then another trip into Vaca to confirm the proximity of both both sites with smoke, hammering, fireworks, radios, etc. Some time was wasted digging down too deep having had smoke appearing through the floor from the boulder choke at the northern end of the molephone passage in Vaca. Eventually, on the eighth day of activity - August 15th - the connection was made. This is through the left hand wall (now with tube installed) about 8m down the dig and linking with a bouldery slope and excavated crawl at the top of the original climb above the original molephone station made in 2013.
   Three more days in the summer and another three in the autumn saw more work with concrete and tube transported from Matienzo.

   After the wettest period for decades, the connecting crawl was found collapsed at the start of the 2015 Easter expedition. It took a couple of days work to re-open the connection.
   Because of the continuing threat of wet sediments collapsing into the crawl, it was enlarged to take another section of tube and this was installed at the end of the summer expedition, 2015. In order to get the tube down the entrance climbs, a 2m section was cut in half then each half cut in four lengthways. Each piece had location pegs glued in place and metal straps installed for bolting together in situ. (Photos below).

   A small mud slump was cleared from the far end of the connecting crawl at Easter 2016, before further explorations started.

   More work with blocks and cement is required underground to lessen the risk of any further collapses.

   The Survex 3d file, below, shows the Wasdale Screes area of Torca la Vaca along with the Molephone point and the entrance to BigMat Calf Hole, along with others. (The surface survey line and point labels should be shown. The passage walls can also be shown in the elevation.)
   The construction supplies company, BigMat in Ramales, generously donated 6m of 60cm diameter double-walled plastic drain pipe, most of which has been used in the entrance and connecting crawl.
   Other sites of interest in or around the depression over this end of the Torca la Vaca System include 2916, 3594, 3905, 3906, 3914, 3924 and 3925.