(Part 1)
Last time we were here, back in 2014, it was a frustrating weekend. We’d planned as well as we could, but we’d ended up wrestling stubborn pipes in a sea of sludge with a finicky pump that was struggling with the viscosity of the gloop we were trying to pump.
After a suitable break digging and exploring the extensions beyond the Ice Cream Trail, Eldon hole and more recently in Rowter beyond the Origin, talk turned once again to the sump. The passage at Decisions Decisions is very large, and even in the smaller section leading to the sump it is apparent that the passage is sizeable, albeit largely choked at this point, leading to optimistic speculation as to what might lie beyond. This time around we were increasing the generator size, installing comms to the surface, adding an intermediate pond, and adding a new solids-handling pump. It was either going to work this time, or not be a project we’d ever return to.
In the months leading up to our nominated weekend there was vast amounts of planning. Mark and I debated pump specifications, pool sizes, flow rates, pipe diameters and more until we were finally satisfied that our plan was as good as we could make it. Mark R and Mike had a trip down the Wednesday night, managing to install the weighty cables all the way from the surface to the sump and deliver four or five bags of gear. Friday saw day 1 of pumping activities, with Ben, Mark R and I on the team. Meeting at 9 at the farm, we were grateful, as ever, to the farmer at Rowter Farm for letting us transport our kit to the entrance where the generator (and backup) were installed, along with the 5G aerials and router that would facilitate communication. Tim Nixon, our surface support arrived, and Mark and I descended straight to the sump with the two pumps and plenty of neoprene while Ben followed on behind reeling out the Cat5 cable as he went. We connected the pumps and soon had the sump draining and pool filling at a satisfying rate, before adding the second pump to send the water in the pool over the watershed in the Ice Cream Trail. All was going to plan!
Shortly after, Mark and I changed into our wetsuits and Ben joined us at basecamp, impressed that his cable ended about 2 m from the base of the final pitch. In no time he was running a speed test showing we had 10 Mbps internet! He sent a WhatsApp message(!) to Tim to update him, and Mark and I headed to the sump and progressively moved the pump down, with Ben managing the pumps from the switches by the pool. This was where the problems started. After a brief pause in the pumping, our submersible decided not to start; a slight hum, but no rotation of the impeller. Having done our best to plan and spec a reliable setup, we once again found ourselves wallowing in gloop dismantling a pump casing. I removed the (tiny) piece of gravel that had jammed the pump and we were back in business, soon getting the sump down to a level somewhere near where we’d had it previously. A few trays of gloopy mud got dragged up out of the way as we went, before once again the pump refused to restart. This time banging it on the ceiling solved the issue, but this was no easy task with the pump weighing 16 kg and being connected to a heavy pipe. On we went, and again we stalled. This time careful poking with a spanner just about freed the pump, before again it decided not to run. We were getting pretty frustrated by this point as we had to resort to dismantling the casing once again. This was feeling all too familiar.
We discussed plans for the next day, which was the main day we had pencilled in for sump-draining, and decided on some modifications we could make to the pump to increase reliability and out we headed. Back at Mark’s a new hole in the pump housing was drilled, a cover installed, a new tool for freeing the impellor fabricated, and a perforated bucket made to sit the pump in. We felt a bit more optimistic about our prospects.
9am on Saturday saw 9 of us meeting in the cloud at Rowter Farm. Seven for underground: the three from Friday plus Chris Haigh, Toby Buxton, Mike Yaxley and Adam Parkes, this time Mark Wright and Tim Gould on the surface ensuring the generator kept running. We were pleasantly surprised to find that our main stream diversion pipes meant the sump had only half filled from the day before and in less than an hour of (stall-free) pumping we were where we’d left off the day before. This was where things got muddy. Tray after tray of gloop was hauled all the way from the sump to the pool at the pitch. Digging conditions were pretty awful and it wasn’t long before we were at the limit of the water that we could pump with no sign of the remaining slop sump breaking. We were cold, making little progress, and generally fairly dispirited. Time for a brew.