Ann: Colluli Drilling and Feasibility Update , page-6

butchy,

Only 20% was used due to it being the first layer of high grade sylvinite. This provides an easily determined economic value with low process risk which returned an IRR of 42%. It also simplifies project financing as any further CAPEX to fund the different process of the lower levels may come from profit. The sylvinite from the upper layer is used to produce MOP which is easily sold into the current market.

The deeper layers (part of the other 80 odd %) are being investigated to produce SOP which sells at a premium to MOP.

So I doubt they will include 100% of the ground in area A. I would assume they would increase the size of the ground but still just take the high grade sylvinite.