personally, I doubt the other ground will add much value (but it could)
it is a 'carnalite' deposit, required solution mining, meaning additional & different front end (but not back end) CAPEX is required
of course, it is a very high grade & thick (superior) carnalite deposit, good for long term. but in the short term (next 30 years) it would probably not be mined. but it could
in Brazil, Vale are investing an expensive $2B (for 1.2Mtpa) & probably a further $2B (to up it to 2.4Mtpa) on a mediocre carnalite deposit called 'Carnalita', using an obviously expensive hot water injection mining method. the project got the green light & should start construction next year
I have not seen a feasibility study on it but at least the capex (rather then unknown opex) is expensive