Not au fait with Net Smelter Return, anyone care to elaborate?...

Not au fait with Net Smelter Return, anyone care to elaborate? 'it has purchased the 2.5%
Net Smelter Return (“NSR”) royalty over ....the bulk of the Ore Reserves defined at Warrawoona'.

This royalty was going to go to who?

2.5% is the whole of the royalty?

Cost us 4m shares = around AUD$24m at today's price, hopefully more at next year's, etc, ie that 'cost' will rise. 'Fleasbarn' reckons that will give us $49m in six years (Correct?), so a lot more if we extend LoM. So, calculation of benefit is complicated and subjective really, though knowing DR it should be good.

Please advise, mining buffs