Exploration drilling has found "broad widths" of gold south of Devonport, London-listed Greatland Gold has announced.
Greatland Gold said the initial results from diamond drilling at its Firetower project 35 kilometres from the city "confirm the presence of broad widths of gold mineralisation".
"This is a promising start as these early results highlight potential depth extensions and good continuity of mineralisation between sections drilled to date," chief executive Gervaise Heddle said.
"We look forward to providing future updates over the coming weeks, including results from drilling at the previously untested Firetower East project."
The company had previously said the project had potentially one million ounces of gold.
That would be worth about $2.18 billion.
The project covers 62 square kilometres.
It is in the eastern part of the Mount Read Volcanics belt, which has supported much of Tasmania's mining industry for more than a century.
Greatland Gold said gold mineralisation was first found at Firetower in the 1970s
" ... this was not followed up until the early 1990s with reconnaissance drilling," it said.
"More modern exploration by Greatland and joint venture partners has included soil geochemistry, geophysics and diamond drilling.
"Drilling to date has, in general, tested approximately 250 metres of strike at the main Firetower prospect."
The exploration drilling program, which started in June, will include 15 holes of depths between 50 metres and 250 metres.
The results reported so far were from the first six holes.
The company has five other Australian projects.
Four of those are in Western Australia and the other, Warrentinna, is 60 kilometres north-east of Launceston.
Warrentinna is seen as a potential open pit mine.
The project covers 37 square kilometres.