Yet another video of Giants

I've got myself a Go pro as a present so here's another video of a trip down Giants as my first attempt at gaining viral fame. Feel free to give it a watch if you've got 20 minutes spare


The trip was down to East Canal but the battery konked out in the upper galleries but much rubbish was spouted.
 

cap n chris

Well-known member
With zero intention/likelihood of ever going into that cave (cos Radon*), it's good to be able to see what it's like so thanks for posting.

[* Giants Hole near Castleton has what is probably the greatest recorded radon daughter concentration in any natural cave in the world, 42 WL (- 155,400 Bq m-3 equilibrium equivalent radon gas. Notifiable level for HSE purposes is 300 Bq m-3]. Source: https://docksci.com/abstract-health...n-british-caves_5cf60bd7d64ab202e9a141bd.html
 

wellyjen

Active member
With zero intention/likelihood of ever going into that cave (cos Radon*), it's good to be able to see what it's like so thanks for posting.

[* Giants Hole near Castleton has what is probably the greatest recorded radon daughter concentration in any natural cave in the world, 42 WL (- 155,400 Bq m-3 equilibrium equivalent radon gas. Notifiable level for HSE purposes is 300 Bq m-3]. Source: https://docksci.com/abstract-health...n-british-caves_5cf60bd7d64ab202e9a141bd.html
Radon is a big problem in Giant's. When the BCA were filming their well known advanced caving techniques instructional film The Descent down that cave, they ran in to some previous cavers that had been mutated in to echo location hunting cannibals by the high levels of the gas.
 

pwhole

Well-known member
With zero intention/likelihood of ever going into that cave (cos Radon*), it's good to be able to see what it's like so thanks for posting.

[* Giants Hole near Castleton has what is probably the greatest recorded radon daughter concentration in any natural cave in the world, 42 WL (- 155,400 Bq m-3 equilibrium equivalent radon gas. Notifiable level for HSE purposes is 300 Bq m-3]. Source: https://docksci.com/abstract-health...n-british-caves_5cf60bd7d64ab202e9a141bd.html
It's OK between November and March, which is when I go, if I must. I suspect the volume of water going in keeps it under control. You would think it would be worse in winter with the outward draught, but it isn't.
 

Rob

Well-known member
It's OK between November and March, which is when I go, if I must. I suspect the volume of water going in keeps it under control. You would think it would be worse in winter with the outward draught, but it isn't.
Surely in winter it's an inward draught (i.e. in Giants and out Oxlow/Maskill)?
 

pwhole

Well-known member
I did wonder whether that does occur, but wasn't sure how much throughput there would be via the CoH in winter.
 

Pete K

Well-known member
Atmospheric pressure plays a significant part in radon levels underground.
During the summer, on average, there are high pressure systems and outside air temperatures above those of the cave air. This has the effect of keeping the cooler air pressed down into the cave. With less air exchange with the outside, the radon can build up.
During the winter months there are more low pressure systems and the outside air temperature frequently falls below that of the cave air. The low pressure sucks the air out, drawing fresh air in. The cold surface air sinks in to replace the 'warm' cave air that is rising out.
That is why you generally get more radon in the summer than winter.

However, each weather and pressure condition could potentially occur at any point during the year, so what the radon levels are on one day can be quite different to the next. Also, a very deep low pressure any time of year can draw even more radon from the rocks and sediment in the cave and lead to very high levels. Even the wind speed and direction can no doubt affect it. It's really complicated! We can make the generalisation that radon levels are typically higher in the summer, but in reality, the actual weather and pressure of the day has a large effect on the actual concentration of radon you will encounter on any given trip.

I've had 21 'working' hours in there so far this year, which is estimated to be about 16% of my annual allowed dose of radon. By contrast I have clocked over 150 work hours in Cwmorthin, which has only consumed 4% of my 6mSv allowance.
 
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