Northern Star acquired an initial 25% of the project in 2015 for $11 million and 4.3 million shares, and can earn up to 60% by sole-funding work under a joint venture.
Under the joint venture, Northern Star was to use its best endeavours to achieve commercial production by July 31, 2018.
The project will not achieve production next month.
At the time of the JV deal, Tanami was granted a put option that gave it the right, but not the obligation, to sell 15% of Central Tanami to Northern Star for $20 million in cash or shares at any time up to the earlier of three years after completion, or at the achievement of commercial production.
Tanami said it plans to exercise the first put option by July 31.
RBC Capital Markets analyst Paul Hissey said th...