The business case for IVR

While waiting for the DFS I ran my own business case on IVR on only the Silver resources. Not the Lead, Tungsten or other prospects.

57 million ounces Silver in ground at
say 30 million recoverable @ Aus $56.00 per ounce = $1,680,000.00 (1.68 billion)
less 130 million to build the mine and plant and 10 million working capital, but let's say 150 million to be covered.
Let's say 40 million operating costs per
year for 8 years to run the mine and plant.
So less 150 + 8 x 40 = 1,680,000 less 150 less 320 leaves us Aus $ 1,210.000 bill ion before tax.
Say 30% tax rate so remove $ 383 million.
Leaving Aus $ 847,000,000 million.

Say there are 2 billion shares by the time of mining.
Divide 847 million by 2 billion and then divide by 8 years of mine life
= 42.35 cents per share, without a Silver price rise and I suspect a reasonable Silver price rise this year.

divide your 8 years by 42.35 cents
Allows a dividend fully taxed of .0529 cents per share per year or Au $ 52,900.00 per million shares per year.
For every million shares you'll receive Aud $423,000.00
What am I missing?
I'm missing the interest on the 150 million to build the mine.
And I don't know about down stream processing costs off the plant.
Interest at 10% for say 3 years until it's paid off is 45 million, (tax deductible)
and let's say 50 million for down stream offsite processing. Truthfully, I don't have a clue but It feels like a reasonable contingency to allow.
So removing another say 100 million from $847 million is $747 million and comes out as 37.30 cents over 8 years mine life or $373,500.00 return per million shares.

Does anyone have considerations to add ?