Junior producer Pantoro (ASX:PNR) is finding bonanza grade gold – above 300 grams per tonne — below the deepest developed level at its flagship mine in northern Western Australia.

There’s no actual definition of ‘bonanza’ by the way – it’s just a way to describe speccy gold grades.

In fact, there’s no official definition for high grade either, but it’s generally accepted an orebody above 5 grams per tonne meets that criteria.

That makes recent drilling highlights of 1 metre grading 317 grams per tonne pretty amazing.

The 50,000 ounce a year Pantoro has hit a few speed bumps on the road recently at its Halls Creek Project, which includes the Nicolsons and Wagtail mines.

But this new drilling results establish continuity of the high-grade ore zone to more than 450 metres below the surface and, importantly, Pantoro still haven’t found the end.

“As has always been the case at Nicolsons, the mineral resource is limited only by the drilling which has been able to be undertaken to date,” Pantoro managing director Paul Cmrlec says.

“Our geological knowledge of the ore system is continually improving, and these very high-grade results show that mining at Nicolsons is likely to continue well beyond the current ore reserve to substantial depths.”

Pantoro intends to update its mineral resource and ore reserve statements later this year.

The Pantoro share price has ranged between 15.5c and 38c over the past year.