Another factor with juniors are large short positions. On the last financial sense there was a good discussion about this. It seems like they haven't been doing transcripts the past couple weeks, but I believe it was in the  2nd part of the Big Picture. ("Buy Them While They're Short -- In Supply")

http://financialsense.com/fsn/main.html

I believe there is a large short position on Kimber's TSX share.