true that, you would have to work 2 weeks on (1wk Day & 1wk Night) & 1 week off.
However if you do the maths... 2weeks * 12hrs = 168hrs worked over 3 weeks (2 weeks on + 1 week off) = 168hrs / 3weeks = 8hrs/day (incl weekends)
So it works out to be 8hrs/day on average (over the year) but you end up on a salary around the $100,000 - $200,000 mark - http://iminco.net/mining-job-salaries-how-much-can-you-earn-mining-careers/
but you're only home every 3rd weekend if you look at it from the other side haha
...and you have to move to Perth, who would do that