Hi-tech Mining
New mining buildings have been added: copper drills, manual oil drill, oil drill and deep drills.
Copper drill: copper drills that can be built like the ore drills.
Oil drill: Fuel can be mined.
Deep drill: it is divided into two types: ore and copper. It can mine in a place without resources, but it needs fuel.
The copper drill is unlocked together with the ore drill. The manual oil drill is unlocked at level 2. Oil drills are unlocked at levels 3 to 5. The deep drill is unlocked at level 5.
