Good deal. Your snake will love it.
Dutch, it's been mentioned here a few times. I'm not saying I believe what's been said, but the more you hear....
I don't know how long snake mites can live in substrate without a host, so an answer to that question might clear things up a bit. Freezing is a good idea. When I used aspen back in the day, I always froze it.
1.0 = one male snake
0.1 = one female snake
0.0.1 = one snake of unknown sex
1.2.1 = one male, two females, and one unknown