In ground $ value assuming 85% recoverable.
Resource Silver prices per ounce.
$15 $20 $25
------------------------------------...
217 million oz. 2.77 billion$ 3.15 billion$ 4.6 billion$
500 million oz. 6.38 billion$ 8.5 billion$ 10.6 billion$
1 billion oz. 12.75 billion$ 17 billion$ 21.25 billion$

Value per share assuming 50% of above values as net profit.
Silver price $15 $20 $25
------------------------------------...
217 million oz. $5.72* $6.51* $9.50*
500 million oz. $13.18 $17.56 $21.90
1 billion oz. $15.42 $20.57 $25.71

The * values per share is what we should be at IF ( yes a big IF) you do not attribute any value to the potential resource.

As for higher silver prices than those stated above, just multyply by the desired factor.