greaser,
Not saying they all do as this would be called generalisation! Some company's require high time pilots for mining contracts (which i might add until recently were hard to source) However many operators would rather sign a bare minimum pilot up who will be there for at least 12 months service which seems to be the industry norm. Whatever your case, being an experienced multi engine piston driver will limit your opportunities in the employment market.
An old piece of advice that was pure gold? Never quit your job or sell your car until you have a new one lined up! (works with women as well :P)