Ann: Rincon Lithium Project Update, page-122

Im thinking its largely due to the agreement between the parties involved, the amount of $$ being put to the table and the length of the OT arrangement being discussed and, largely, who we are actually dealing with and who we have on the other side (Tier 1).
Also the high degree of customisation on the quality of the battery grade specifically to the details and specs of the OT'ers requirements which has been in the works for some time now and I suspect with not just one potential taker either. I doubt this will be a MOU (not ruling it out) and a silly non binding agreement like others stocks which have broadcasted loud and proud, only to just fall away. This is for longevity for the company. IMO thats why it's taken so long on top of other major delayed hurdles that have been discussed on these threads incessantly. Time will tell.