This is the best shot I could get without endangering myself. There is a piece of BG rail set in the inner walls that could have been used to anchor railway workers when they descended the depths of the ventilation shaft. I call on Lalam to fabricate a (collapsible, lightweight, man portable...) pipe with a camera mount welded at the end - then maybe we could position the camera in the center of the shaft and get vertical views down the abyss.