The Secret Mine is the fourth mansion that Luigi goes to in Luigi's Mansion: Dark Moon. This is the shortest mansion mission-wise, with 3 missions instead of the usual 5, a boss mission and a bonus mission after capturing the Boos in the area.
This mansion is located on a snowy mountain, which causes the mansion to be frozen over, inside and out. Also, as the name implies, the mansion was built near a now abandoned mining area, which Luigi explores. Professor E. Gadd sends Luigi to the Chalet where a group of Toads were studying the ghosts. When Luigi finds a Blue Toad he does a little dance causing the ice under their feet to break and they drop into a cave. The Chalet is built just above an abandoned mine that Luigi needs to explore. Aside from the ghosts, this is also home to a few Fuzzballs that follow Luigi, but don't actually hurt him.
The mine near the Chalet was originally a secret mining project run by an unnamed company. It is unknown why the mines were abandoned but years of neglect have caused it to become flooded with snow and ice. The mine contains crystals with special properties. One of the properties of the crystals is that they strengthen ghosts that go inside the crystals for a certain amount of time. The Boos collect a large amount of crystals and take them elsewhere. At the bottom of the mine Luigi encounters several Boos where they strengthen up normal ghosts, causing them to become more powerful and gain white crystal markings all over the body.
Some determined geologists started a mining operation in these snowcapped mountains. But when the ghosts started moving in, they got scared and abandoned it!
Some determined geologists set up a mining operation in these snow-capped mountains, but they got scared and abandoned it after the ghosts moved in! (PAL version)
(Ground Floor in PAL version)
Names in other languages