The $3.40 and $4.64 are based on a BA price of 750 and a 20 year mine life. Those assumptions are both 25-30% short of current values. Just accounting for that difference would take us to $5 and $7.5.
Also note some comments in the report like "The revised mine plan announced by ABR delivers potential of 2.5x available boron to the project. We have not taken the extension of mine life from this into consideration for this valuation.". So you can take those $5 and $7.5 and get to $12.5 and $18.75.
Then later in the report you have the peer comparison in the US which gives $9.18. Again based on the assumptions of BA at 750 and a 20 year mine life. So I read that as an addition 2.5x premium based on earning multipliers on the NASDAQ over the $12.5 and $18.75.
