That has to be prevented from happening, and those mines have pumps in them. Otherwise land around gets poisoned (and also eroded).
So putting useful objects inside those mines at least makes them not just passive expense.
If someone wants to know what if you just don’t pump the water out of an unused mine, leaving it be, then they can read what happens in Donbass now that nobody takes care of those many depleted mines there, due to war. It’s like Mordor basically.
Since the person above didn’t actually give enough information for someone to understand:
Look up “Acid Mine Drainage”. Its when sulfide minerals react with water and oxygen to produce sukfuric acid, and it occurs in pretty much every mine once it’s opened, and continues to accrue and leak for thousands of years. Ancient Roman mines are still leaking the toxic, acidic sludge today, and will continue to do so for the foreseeable future.
That has to be prevented from happening, and those mines have pumps in them. Otherwise land around gets poisoned (and also eroded).
So putting useful objects inside those mines at least makes them not just passive expense.
If someone wants to know what if you just don’t pump the water out of an unused mine, leaving it be, then they can read what happens in Donbass now that nobody takes care of those many depleted mines there, due to war. It’s like Mordor basically.
Since the person above didn’t actually give enough information for someone to understand:
Look up “Acid Mine Drainage”. Its when sulfide minerals react with water and oxygen to produce sukfuric acid, and it occurs in pretty much every mine once it’s opened, and continues to accrue and leak for thousands of years. Ancient Roman mines are still leaking the toxic, acidic sludge today, and will continue to do so for the foreseeable future.