CompuServe Messages

Steve, I'm putting your name on this as you are a geophysicist and it seems your field. I was in the Valenciana mine a couple of days ago, about 500 mts below the collar, in a dead-end tunnel. Where there was natural air circulation, the temp was about 18 deg C; where the natural ventilation stopped, the temp jumped to 30 C, continuing to about 60 C (140 f) near the end of the tunnel. PHEW. The funny thing was that the increase was not constant along the tunnel: there were hotter and cooler zones, lasting between 1 and 3 mts each, so sharpley defined that you could have have ruled them off with a chalk line. Can someone explain the reason, please? The mine manager explained how the "ancients" (miners of the 1600's to 1800's) dealt with the ventilation problem in a blind tunnel and showed me an example: they built a very solid stone wall 50 cms thick from floor to ceiling, right down the center of the tunnel, stopping just before the work face. This must have created a circular air flow. We could not test the system as the wall had been perforated in places by later miners, and the tunnel was no longer blind. Any comments? Chris