a left field and high risk alternative - since your a geo i would not go for more extra geo education as i expect your resume will cover u getting the next job, NOT the fact you have dome extra ciricula!!!!
If you have a smal stash and feel able - it is reading and following hte mining and expl cos on the ASX or elsewhere and trade in these to make some extra income, and if u were able - i would rather borrow the 25K and trade in stocks than do extra educatin.
the trap is if u are a beginner in trading stocks it is where u are most vunerable to stuff up, but i suggest u have a little go on something and start to learn this trade - it can very helpful especially with a geology background in that u can very well understand the Co reports and understand also what is not said in the Co reports.
A tip for starters - Cos with good cash in bank so no CR for a time, low No of shares on issue and some event like drilling on what looks attractive target is going to happen in near future - they are out there!!