The Tellus Geological Survey has completed a five month in Donegal and Mayo, with the latest phase now complete.
The survey plane began flying over parts of Donegal in April, and has now completed it's flightsd for this year. Data from the survey is now being assessed, with results due early next year.
The Tellus project began in 2005 with a survey of Northern Ireland.
Now, 50% of the island has been surveyed, including all the border counties.
Emma Scanlon is a spokesperson for the Geological Survey of Ireland which is overseeing the Tellus project. She says this is a significant milestone.............