The company has been using the expression "partner / partners"....

The company has been using the expression "partner / partners". I do not recall that they were talking about a specific number. I assume (!) that this project (life of mine: 50 years) is too large for one partner, so it is likely that they need to find more than one. If they found one partner who is willing to fund 25% of the project (example) and who signed a contract they would have to announce this. I am sure about this because the company told me so. As we haven't seen such an announcement, no partner has signed a deal yet.

So basically you are on the right track imo.

The dept side has several conditions. One is - if I recall this correctly - that funding is secured ( = dept providers and equity providers "found"). So they need to find partners who invest at project level (approx. 50%) and the other half will come from debt which I assume is not a big problem.