Excavation is the skill of using a shovel to remove things like dirt, sand, gravel and other blocks. Excavation xp can only be gained by using a shovel on server-generated blocks such as dirt, sand, gravel, and other blocks.
Perks of leveling up Excavation:
Giga Drill breaker: This is an active ability that grants triple the drop rate, exp gain, and adds 5 levels of efficiency on a shovel. To use this ability requires to right click a shovel then use it to break something like dirt. This ability lasts for 2 seconds base and gains an extra second every 50 levels.