It's not 60k for captains. As far as I know, The Beechjet is operated by Business Aviation Solutions (Sydney based), servicing the INPEX contract.
I don't know the current salary figure, but it certainly was reasonable last I heard. The only 60k (ish) figure I can think of for a jet in Darwin would be the Jet City Lear 35 FO job, also operating for Careflight.
Edit: Sorry, just read the ad. Doesn't look like the INPEX contract, but I'd say it's still operated by BAS.