I work weekends at a gold mine. I'm a lab tech so its mostly manual labour and some brain stuff. I started at 18 and trained in the workplace. A fair few people come from uni degrees in Science. I'd absolutely recommend mine work as a temporary thing, but long term it isn't really worth it. The money I make now is a huge amount compared to most over 22 year old uni engineering students (mainly due to weekend penalty rates 1.5 pay on saturday double pay on sundays). But long term it's not really enough money or compelling enough work to sustain a long career.
TLDR: Mining Lab Tech
if its a temp job while studying 10/10 pays great with very little time commitment
as a career 4/10 wouldn't be able to sustain a single income house long term and the works pretty boring and reasonably labor intensive, could probably fuck your back after 5 years if your not careful