If you are trying to progress to the next level but receive a message saying, "All mineshafts need to be activated," it means there is still unfinished business in your current mine layout.
How to Spot and Clear Inactive Mineshafts
To complete the level requirements and unlock the gate to the next mine, you must ensure that every single shaft on the map is operational.
Look for Safety Cones: Scan the left and right sides of your current mine. Inactive mineshafts are easily identifiable by the bright orange and white safety cones placed around them.
Clear the Obstacles: If a mineshaft is buried or blocked, you must order your Goblins to break the surrounding rocks first.
Activate the Shaft: Once the path is clear, tap on the shaft to rebuild it and kickstart its automatic production.
As soon as the final safety cone disappears and all shafts are up and running, you will be able to proceed to the next mine immediately without any issues!