The structure is the entrance to a mineshaft, with a drill in it! It also has a desert version where it is made out of sandstone instead of logs.
Together with the shaft, there will spawn a miner villager!
The villagers trades ores, gems and tools. It has Villager ID 13 by default, but you can of course change this in the configuration file.
Hope you enjoy and as always: Forge 1180 :D