Fossils under Bendigo could be buried with 32 million ounces of gold

They would punch through to a world shared by little-known fossils and more importantly, for them, a share of the 32 million ounces of gold thought to lie hidden in central and northern Victoria.

Few have drilled east and north of Bendigo because of a vast inland arm of the Pacific Ocean that dominated the region 20 million years ago, hiding anything that hinted at the riches that may lie beneath our feet.

But now Victoria is in the middle of mining boom complete with modern day research which suggests land east and north of Bendigo might make someone very rich indeed, if they can win the right to explore there.

The Victorian government has opened four blocks of new land stretching from Kotta, near the Murray River, down past Kirkland Lake Gold's Fosterville goldmine, following ancient underground fault-lines through rock.

Those faults once acted as a sort of "plumbing system" that allowed gold-bearing fluid to rise from magma deep within the earth's mantle until it oozed onto the sea floor, the Geological Survey of Victoria's Cameron Cairns said.

"The central and western region of Victoria is unique. It doesn't represent a huge area of the earth's crust but it's produced a ridiculous amount of gold - about 80 million ounces so far," he said.

"It takes a whole raft of geological processes coming together in a relatively short space of time to make gold deposits.

"Then, you have to preserve them. Rock erodes all the time but in this instance some of it might have been preserved because it was covered in a younger sea."

The sea bed laid down by this younger sea is thought to hide another one formed when tiny creatures called graptolites floated above the ground you now stand on.

That would have been about 467 to 485 million years ago, Museum Victoria researcher Fons VandenBurg said.

He has spent a decade writing about Museum Victoria's collection of these microscopic creatures, which hooked themselves together into colonies that floated through Bendigo's tropical sea, feeding on plankton.

"The colonies were quite small, perhaps 10 or 20 centimeters across," Mr VandenBurg said.

"Bendigo's quite famous for having a very large variety of these sorts of fossils."

So are other parts of the world, helping geologists date how old rocks are so miners can zero in on the right areas to dig.

Graptolites were food for other sea dwellers and have been found in fossilised excrement of so-far unknown predators, Mr VandenBurg said.

Museum Victoria has the world's largest collection of graptolites, thanks to the same series of geological processes that left Victoria with so much gold to discover.

Despite the size of that collection, scientists know nothing about what kind of graptolites might be hiding below new sections of land being opened up for exploration.

"They are deeply buried. In some cases they will be down hundreds of metres," Mr VandenBurg said.

Now, the government wants to cash in on the ancient sea beneath our feet.

For the first time in the state's history, a royalty will be imposed on gold dug up by miners.

The royalty will begin in January and cannot come a moment too soon for the government, with resources minister Jaclyn Symes last week revealing the amount of gold dug up in Victoria surged 16.7 per cent in the 2017/18 financial year.

The state has also seen a 137 per cent increase in the number of new licences issued to miners for exploration, with Ms Symes expecting tenders for new land east and north of Bendigo to add to the growth.

Each tender will require successful companies to demonstrate they will work with traditional owners and communities, she said.

"The increase in spending on Victorian exploration and huge growth in jobs means confidence in Victoria's minerals sector is high," Ms Symes said.

The government hopes the gold royalty, which will take effect in January, will bring in in $56 million from the state's four biggest mines including Fosterville's Kirkland Lake Gold operation and Costerfield's Mandalay Resources' shafts.

Fosterville's gold mine, which last September dug up the third highest amount of gold in the nation, taps into some of the same ancient fault-lines that run north beneath both seabeds.

That mine's success is fueling the multi-million dollar spends on exploration drilling across the state, which in 2017/18 came to 191,299 metres - about the same distance from Melbourne to Echuca.

Geologists cannot tell exactly where the estimated 32 million ounces of gold thought buried is hiding, whether it pooled into vast seams all those years ago or whether it is more spread out, Mr Cairns said.

Nor can they tell how much of it was lost before humans stepped foot on the earth - washed unnoticed by colonies of graptolites and their mysterious predators, into the ocean's depths.

One thing is certain, according to Ms Symes.

"We're seeing Victoria's next gold rush."