If there was no increase in resource there is already 90 million...

If there was no increase in resource there is already 90 million tonnes as far as understand.
At 90 million tonnes it would be economical I presume.
If it is economical at 90 million what would be or should be the SP and why isn't it closer to that price rather than 10 to 13 cents.
How much of a price difference is there between indicated and resource grade for any stock?
If it was 150 to 200 would they build a bigger operation.
I'm just trying to understand the excitment.
If someone like FMG annouce an increase in resource of 50% aren't they just priced on volume they ship out and small increase in SP on the increase in reseve.
If YRR was viable at 90 million tonnes and it had a minelife of 10 to 15 years how much would an extra 5 years be worth.
Thanks for intellegent answers .No ramps please