I had to check the Wikipedia for Sandgroper! I thought it might be Australian slang for a pervert living out in the outback or something like that, kinda like good ol' Mick from the Wolf Creek movies. But wow, it appears you actually have a miniature version of those Graboid monsters living underground, just like in those Tremors movies
Crikey, I love Australia even more now and cannot wait to settle there some day, hundreds of miles into the wild isolation of the Australian Outback where I can escape modern society - must be absolute bliss!!!
Anyway, thanks for the support mate! I say bloody G'day to you, and don't forget to give my regards to Skip!