Hills are a natural feature in CastleMiner and CastleMiner Z. They are always covered in dirt and grass, but can have huge holes in the sides of them, thus leading to a small or big cavern. They are a common sighting in CastleMiner and CastleMiner Z.
Clearing of Hills can be a strenuous task, even for players with Diamond Spades and Bloodstone Pickaxes. There are an estimated 600-900 blocks of dirt and rock that make up a normal Hill. Caverns and Caves inside of Hills can help a player clear them, but can also be a danger in Survival Mode as Skeletons spawn in them.
Note: Dragons can tear off the sides of the hills with their attacks.