All early mid game smelting needs in one compact build. The idea is to put this down as soon as you have unlocked ILS, to support a robust mall and some early science production.
Uses 6 ILSs to import ores and feed 31 columns of 27 smelters each. It fits in a 100 by 160 cell area. Smelters and tesla towers are laid out in a pretty regular grid.