The temperature drops several degrees as you enter the mine. The cool air offers a welcome reprieve from the oppressive heat of the jungle, and a light wind brings a musty, earthen smell to your nostrils. As the daylight behind you fades, it’s almost as if you are walking into nighttime. A solitary lantern hangs from a support beam, casting a flickering light across the walls and reflecting off the mine cart track wending its way into the darkness.