1 Limestone 1060
The initial operation was a catastrophe. I underestimated the speed of the pump stack and overestimated the speed of the magma, so it piled up and went over the wall to the east. This dumped it into the forge floor. Ordinarily, this would not have been a problem, but the magma exploited several safety oversights in the pump stack design.
The main problem was that not all of the pumps were completely sealed off.
A sealed level of the pump stack
An unsealed level of the pump stack
After exploiting this, the pumps above would collapse (because they were stacked on top) and the magma would flow through the open hole onto the vulnerable space of the pump below. Furthermore, none of the pumps were made of magma-safe blocks. The final flaw was that the reservoir on the forge level was not separated from the stack.
In short, a small initial amount of magma fell onto the forge floor, destroying a pump and allowing the reservoir to flow downward.
Five dwarfs died in the tragedy, and several more were injured. We lost forty magma pumps, and the power generator is at reduced capacity due to obsidian forming in the reservoir.
But it was not a complete loss. Before power was severed by a broken pump, we were able to pour some water on the magma in the obsidian generator.
The obsidian generator performed as expected. I have only used up half of my term so far. I need to spend the next season rebuilding the pump stack and putting in the additional safety features (sealed pumps, hatches in the pump tower, separating the forge reservoir, building the pumps out of magma-safe blocks, and raising the eastern wall of the obsidian generator).
'Microcline' Degeltad