draughting sand?

ian mckenzie

New member
Anyone have any experience with airflow permeating apparently solid chokes of sand/silt?  I would have thought it unlikely, but there's a dig here with no airspace that feels cool and there's no breath condensation (common throughout the rest of the cave, which is high, cold and relatively humid). 


New member
When we dug Rubble Rift, we had to pump air to the face to avoid suffocating. Suddenly, we didnt have to do it anymore.. the tube was still 100% silt filled, and we couldn't find the source of the air, but it was there alright..

We learned it took only the tiniest fissure or gap carrying air to keep a point "fresh"..

8m further on we broke into a chamber.....


A while ago we used to dig a completely sand-filled passage in Dan-yr-Ogof. We became convinced there was a draught, and the air quality never seemed to deteriorate, so we took in a joss stick and were amazed to watch the smoke 'blown' down the digging face and out behind us. Sadly we had to abandon the dig after a narrow miss with a boulder that was embedded in the sand, so never proved the point about the draughting sand.

I recently went back with a hot-wire anemometer that showed a resounding '0.00', but I have other witnesses to the joss stick incident, so it wasn't a figment of my imagination. 

ian mckenzie

New member
This particular dig might just add 150m depth to a 500m deep cave, so the question of draught is a significant one.  Thanks for the input...