Just won this.

I'll post photos once it's here, and cleaned up a bit. In the meantime, here's the link to the completed auction w/photos.
Looks like some sort of Luzon bolo to me, with the side/top faceted semi-figural horn hilt, plate-reinforced peened tang, faceted ferrule to match hilt, pinky cut-out, general shape, etc. Any other ideas on it? I wonder how in blazes it got to the bottom of a mine shaft in Butte, Montana?
Another rusty ethnographic pigsticker