We can dig with different tools and for different purposes. Sometimes you dig to use the ground to create other constructions. You can also dig to create paths or to carry liquids or goods from one point to another.
In Need Water, for example, you need to manage a factory by bringing water or oil by digging underground. At the same time, you must collect gems found in the soil.
When you dig, you may need to take precautions to avoid being blocked.