Mine Flooding!!

While trying to mine down to the adamantine there was an accident. Damp stone was discovered, but based on the ramblings of the Spirit of Abel, the miners though they were below an underground lake & continued to dig. they were wrong. They broke into the bottom of a massive three z-level lake that was part of the deep & dangerous third level cavern system.

Water started flooding into the tunnels. Exposing the entire mine area to not only the water, but whatever hellish monsters might live in the lower cave system. Thinking quickly, the miners quickly ran back to a near by magma tube they'd mined around & cracked into the side of it. Causing a torrent of magma to come rushing out. The miners just barely got out of the way in time. As the magma went crashing into the water, plugging the hallway with obsidian.