When the submarine surfaces, compressed air flows from the air flasks into the ballast tanks and thewater is forced out of the submarineuntil its overall density is less than the surrounding water (positive buoyancy) and the submarine rises.
The bouyant force is the capabilty that an object has of floating. Only things that are less dense than water can float on it.
When you bring water inside the submerged submarine nothing happens since the bouyant force only applies to things that float on the fluid we're taliking about.
Surface mining can severely erode the soil or reduce its fertility. It can also pollute waters or drain underground water reserves; scar or altar the landscape; damage roads, homes, and other structures; and destroy wildlife.