Like Rescueable Villages, Gold Mines can be taken & captured.
To gain ownership of a Gold Mine (as with any other Neutral Building) a player needs to order one (or more) of his troops to capture the Circle of Power.
Gold Mines however are more valueable than regular Villages.
Each Gold Mine produces +500
as an additional income to the respective player in control.
And as an extra bonus, the Altar of Hammers can train more powerful units than the standard buildings.
So, defend your Gold Mine(s) well. As any other player can at any time attempt to take it from you. Each Gold Mine also come with a few Guard Towers, and a Gatehouse. However, when you discover a Gold Mine it will most likely lie in ruins. So you have to rebuild itquickly before someone else comes along!