Has Anyone Dived? Overspill Passage sump, Speedwell?

[alastairgott]

Just been revisiting the survey and noticed that on the survey overspill passage sump and Lower bung streamway sump are going parallel if not slightly away from each other. I'm not a diver, but wondering if anyone has visited this sump recently, even if just to check it out.

Seems to be quite close to peak main streamway, but probably about to run underneath, anyone's guess what it does next. - Sounds like it could be a less than perfect sump being "low" and "choked with sand", but things change.

reference on https://www.peakspeedwell.info/index.php/system-information/sumps/16-speedwell-mine-sumps

Overspill Passage Sump:

The low sump at the end is choked with sand, this hasn't been dived.

 

[Pitlamp]

It's awful - flat out over thixotropic sand. Also an extremely dangerous place to get to if the Speedwell streamway is pulsing (the clue being in the passage name). It's almost certainly at the same level as the main Speedwell downstream sump, which has been explored well beyond Overspill Passage Sump and is heading down dip, so unlikely to reveal airspace passage any time soon. It's just one example of a significant number of distributaries from the Speedwell steamway (some active, some active only in flood, and some relict).

I think it was me that found this sump, a long time ago (see CDG Newsletter 66 page 21 for description of the area, together with the original survey on the facing page.) As you'll know, I don't like leaving unfinished business but it's so unpromising I never even considered going there with a tank.

But yes, things do sometimes change (Cliffhanger Sump being a good example) and it's always worth another look, as Rob Middleton brilliantly showed in Cliffhanger Sump at the other end of the same system. Just choose very dry, very settled weather.

 

[alastairgott]

Thank you John, I’ll keep it in the memory bank as a place to send the divers in summer, always good to have a few trip recommendations up your sleeve

 

[Pitlamp]

Er, that wasn't a recommendation, honest . . . ;-)

 

[pwhole]

A few of us went in today, to beat the rain - just some tidying-up, brought out some hose, logger changing etc. Main Rising still wasn't flowing, Whirlpool Passage was perfectly passable and not pulsing, and Cliff Passage was issuing some, but not much. May be a bit trickier tomorrow but I don't know how much it rained whilst we were in there - it was just finishing at 14.45 when we got out. Water was a good 30cm short of the top of The Bung step.