Passage: After defeating a rival railroad company and laying track to supply the US Cavalry near the Mexican border, Amelia meets a prospector named Pierre Beaumont, who helps her and US Cavalry commander, Major Cooper, defeat a Mexican army attacking a fort. Beaumont then leads Amelia to a mine in Colorado where she meets an aged Kanyenke, who has brought Cooper and the cavalry with him. Kanyenke reveals Beaumont as the leader of Circle of Ossus. Amelia, Kanyenke, and Cooper chase Beaumont through the mines, where they find a map to the Lake of the Moon.

Question: A map to a lake was found where?
mines