The Eagle Mine is unique in that it connects with another mine underground. The High Peak Mine was worked prior to WWI. Around that time, the price of gold dropped sharply, making it unprofitable to do the heavy labor required for hard rock mining. During the WWI scrap metal drives, the mine sold all of its heavy equipment for scrap. After WWI was over, the price of gold skyrocketed, and the owners of the High Peak mine wanted to get back in business. Unfortunately, they'd gotten rid of all their heavy equipment. The owner of the Eagle Mine agreed to lease equipment to the High Peak mine. The two mines were joined underground after the agreement was reached.