Yes, assuming the DA is written competently in the timeframe....

Yes, assuming the DA is written competently in the timeframe.
Really as you have stated, 18 months is a big red flag. 1-3 months is adequate for converting a LOI to a signed DA.
But conversely CGM appear to already be doing exploration activities without even a DA.
Might check further into exactly what has been done and how and why.

Tenements in Brazil can be quite problematic. And the DMNP system is not like WAMEX where you can get a really good handle on whats happening - heck in Oz you can even see the which Native title group
is objecting and why and when the hearing is scheduled.