Advance
Efficient Mining
We shall issue a decree to refine every aspect of metal mining within our domain, in an effort to regulate its presence in our markets.
Advance tree
The game files don’t say where this goes: it has no requires, so the game places it in the 
Discovery tree itself.
Modifiers
Expand Mining Cost−10%
Iron Output+10%
Copper Output+10%
Definitionin_game/common/advances/4_choices_adm.txt:182
184icon = efficient_mining
185for = adm