This is a custom music pack for the Ambience music mod.
It contains the songs (made by Kevin MacLeod) from the Xbox Live Indie game Total Miner Forge. Other songs produced by him with a similar tone are also included.
The songs were picked to provide a more immersive experience for the player. Even if you haven't played Total Miner Forge before, these songs should certainly spice up your game.
To install, simply place the contents of the downloaded file into the "ambience_music" folder in your .minecraft folder.