As far as I am aware all minerals in Australia belong to the Crown, Pastural Leases are just that, there is no "right" to the minerals.
There are however a very few land leases that were issued with mineral rights, a few existed along the Sevens River near Stanthorpe Qld, I think there were only about 5 to 10 leases issues for the purpose of alluvial tin mining.
The reason we have Departments on Mines and Energy in each state is to control who is able to mine those minerals and where those minerals can and cannot be mined.
Each State has it's own stringent rules and regulations that need to adhered to and applied before a Mining Tenure can be issued, this must be accompanied with Environmental Protection Agency (EPA) approval.
In Queensland its an EA (Environmental Authority). This is governed by strict terms and conditions including dust suppression, noise and many other requirements, the amount of ground you are allowed to disturb each year and rehabilitation targets to be met, snap inspections etc..
If you are intending to obtain some sort of income from what you find ( In most cases) you should have a Production Permit for a Mining Tenement. Talk to the authority responsible for minerals in your State or Territory before going gang busters with machinery.
The freedom we have to be able to swing a detector in some areas in Australia and keep what we find is a privilege and should not be taken for granted.
If anyone intends using mechanical equipment to move ground in the search for gold on their own property or elsewhere , is running the risk of big fines and confiscation of all equipment in some States.
Such a practice could Jeopardise the privileges of the electronic prospecting fraternity for everyone.
I showed a friend visiting from Botswana a small vial with a few grams of gold I had panned over the years, he informed me if I was in Botswana I could be arrested for having that small amount of gold.
Please don't take gold fossicking freedom in Australia for granted or we too my lose another privilege.