It was from the update dated 7/6/2016: Central Tanami Project...

It was from the update dated 7/6/2016: Central Tanami Project Drilling Update

Tanami Gold Limited (ASX: TAM) (“Tanami” or the “Company”) is pleased to announce the following significant results from the final stage of Drilling at the Groundrush Deposit, at the Central Tanami Project in its JV with Northern Star Resources (ASX:NST). Drilling of 118 holes with over 27,000 metres of Diamond Drilling and 11,000 metres of RC Drilling has been completed. Geological interpretation and resource modelling is currently underway with an updated resource expected to be completed in July 2016.......
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The Central Tanami Project is part of an ongoing JV with Northern Star Resources (Tanami Gold NL 75%; Northern Star Resources 25%) in which Northern Star Resources can earn a 60% interest by bringing the project into commercial production by 2018.
The exact terms and conditions of the earn-in and the JV Agreement have previously been announced. Gerard McMahon Chairman

I then followed this back to an NST update dated 20th Jan 2016:

MORE SOLID RESULTS FROM CENTRAL TANAMI INFILL DRILLING PROGRAM

...The drilling is aimed at establishing Northern Star’s confidence in the Central Tanami Project in the lead-up to a decision to commence refurbishing the Project’s processing plant and start production in the 2018 financial year...

I went back to the previous NST update dated 10th December 2015: CTP Update

The drilling is aimed at establishing Northern Star’s confidence in the Central Tanami Project in the lead-up to a decision to commence refurbishing the Project’s processing plant and start production in the 2018 financial year.

Northern Star has earmarked Central Tanami as one of the sources of organic growth which will lift the Company’s production to 700,000ozpa by FY18.

I went back to the 31st July 2015 and from NST on the completion of CTP deal:

With the joint venture agreement now settled, Northern Star will proceed with its strategy to bring the Central Tanami Project back into production in 2017.

By the chairman's own words (McMahon):

The Central Tanami Project is part of an ongoing JV with Northern Star Resources (Tanami Gold NL 75%; Northern Star Resources 25%) in which Northern Star Resources can earn a 60% interest by bringing the project into commercial production by 2018.

2018 must be in the agreement or the market (us) have been misinformed I would think - the MLX thing I thought showed they weren't that silly - McMahon is clearly informing the market that NST can earn the 60% by bringing the project into production by 2018 - fairly clear to this TAM holder