EDMS said the program will encompass 180 HQ-sized holes, 54 4C holes and 180 LC holes.
EDMS said the extension to its Shenhua drilling contract followed the successful completion of stage 1 which drilled ahead of budget and was also free of lost-time injury.
Six GOS drills are onsite at the project working seven days a week.
The Watermark project covers a 195 square kilometre area in the Liverpool Plains and is Shenhua’s first major international project.
Ongoing exploration is targeting a resource of 500 million inferred tonnes.