The Sustainable Mining Perk improves your gold mine's production and allows them to reset upon destruction.
Your mines produce +1 gold and their income is reset back to 7 every time they are destroyed.
On the day after mines are destroyed, they will not produce anything (like normal). On the next day, their production will reset to 7.
Letting mines run for 3 days and then getting them destroyed will lead to maximum profits of an average of 4.5 gold per day for a cycle of 4 days.
