Entering the high-pressure cutterhead chamber of a stalled twenty-five-foot tunnel boring machine was not a task for the faint of heart.
Giles Croft and Master Borin Bronze-Lung stood inside the steel pressure drop airlock behind the forward inner wall.
Apprentice Tam rotated the brass equalize valve, his hands steady despite the hissing rush of tightly packed air. Within three minutes, the chamber pressure reached one point eight sea-weights, equalizing with the groundwater head at the rock face to prevent water ingress. Meanwhile, the check door was open.
Giles popped the seal on his ears, unlatched the heavy circular steel hatch. Then he stepped through into the narrow space between the cutterhead spokes and the raw rock wall.
The air inside the cutter chamber was hot, metal, and heavy with the scent of ground stone and ozone.
Giles clicked on his high-output halogen check lantern. He swept the beam across the circular digging face.
What met their eyes was not the dull, mottled gray of fiery dark rock.
Directly across the twenty-five-foot circular face stretched a solid, massive stone wall of shimmering, blue-black metal rock. It looked like a solid slab of polished sky iron, interwoven with fine, detailed webs of silver crystal-clear filaments that pulsed with a faint, cold, internal soft glow.
