It would see African Potash, which holds 70% of Lac Dinga via the La Société des Potasses et des Mines SA (SPM) vehicle, receive 5 mln new shares in AAX as well as warrants giving it the option to buy another 2.5 mln (each priced at 5p).
AAX also commits to certain spending milestones for the project.
"This is a positive move for all concerned and fits in with our long-held ethos of helping the African farmer,” said Chris Cleverly, executive chairman.
“The transaction endorses our belief in the long-term viability of the Lac Dinga project.
“We are excited about working with our new colleagues in moving toward a food secure future for some of the world's poorest people."
Meanwhile, AAX founding director, Conal Bunnett said: “We are delighted to embark upon this mutually advantageous arrangement with our project partners, African Potash.
“The Lac Dinga prospect offers high hopes of a significant potash resource on the African West Coast, the success of which will cement a key strategic component in the ambitious rollout of our plan to create a vertically-integrated, pan-African fertiliser business."