Actually it terminated in rock – the bucket landed unevenly and ejected Jack. Loose bits of stone continued to clatter down from above for a little while and hurt his legs, which was welcome as proof he hadn't been paralyzed. The kienspan still burnt; Jack held it in a death-grip and watched the blue flame pour out of it and turn yellow as it moved sideways along the shaft, contrary to the normal habit of flames, which was to tend upwards .Jack kicked the bucket out of the way and did some moving about, and found that there was a rapidly building draft, approaching a breeze, moving toward him along the tunnel. But when he backed up to the other side of the shaft opening in the ceiling, the air was moving the opposite direction. Two flows of air converged at this point and moved up the shaft, starting now to make a certain wailing noise that Jack could not fail to liken to damned souls or whatever. Now he understood why the Hexen had gone to work felling trees up above: they knew that with a sufficiently enormous fire they could suck all of the air out of the mine.