At then end of the tutorial about resource gathering a section has been added about the secondary resource and how to mine it. The goes through all the steps:
- Unlocking extra build options by powering a factory with tower blocks.
- Gathering secondary resources using only primary resource structures.
- Building at a distance from the base with a builder tower.
- Building Advanced Factory, which can build Missile towers.
- Using the missile towers to boost the mining of secondary resource.
There is always a choice to be made in how you use your towers. Upgrading buildings, Mining resources, exploring or combat.