After Smelting has been researched the mining shaft will be available to craft in the Production tab.
Ensure the mod is active as well. I've installed some and forgotten to turn them on before.

Thanks so much

This is listed under the smithing research btw for anyone having trouble

After finding it in the production menu, I have build it. But when its finished, I cant select it. Neither left nor right mouse button. I also tried to select a pawn first and than right click on the shaft ... nothing works. Energy is available. Is there a trick?

引用自 Farsuf：

After finding it in the production menu, I have build it. But when its finished, I cant select it. Neither left nor right mouse button. I also tried to select a pawn first and than right click on the shaft ... nothing works. Energy is available. Is there a trick?

broken mod fr