When I first saw the headline of this thread, I expected to hear positive stuff about the theme. I was really surprised when I saw that people hate it.
Personaly I thought it was really cool. The music in Skyward sword was not as cool as in Ocarina of Time, but The Lanayru Mining Facility theme really gave a + to Skyward Sword.
Honestly, I've never really paid attention to the song... I was too focused on what I was doing in the place... I'll have to listen to it though next time I load up SS.
I loved it. It was also fitting for the dungeon, which had this ancient creepy feel to it. Definitely my favorite dungeon in the entire series as well.
I don't really like it when it lasts the whole time, because for me mostly all of the dungeon themes are kind of ambiance and unobtrusive. This I felt took over a little bit more than was good for the entire length of the dungeon. I kind of like it for a little while though.