News: MR1 Transalta Announces Acquisition Of 50% Interest In Early-Stage Pumped Hydro Energy..., page-21

It's clear that the end goal for TransAlta is to buy out the remaining 50% by 1st Jan 2028.
This is based on the project proceeding to the construction phase / final decision.

This leaves you with four questions.

1) Will permits for this project be given by relevant authorities ?

2) Will this timeline be achieved/ will it be earlier?

3) Can Montem fund its half of the project until this date ?

4) What will the final purchase price be if TransAlta makes a take over offer