Based on the official resource estimate for Sol1 (including Sol12) here is the math to determine the "theoretical" share price at first ore:
2,800,000 tonnes resource (Sol 1 indicated and Sol1 & Sol12 inferred) [Note: these are "unrisked" estimates and not discounted for uncertainty]
$2,024,820,916 gross resource value at current prices
1,200,000 tonnes per year mined [Note: at this extraction rate, Sol1 & Sol12 will be EOL in appx 2-1/3 years <-- thus the importance of a strong "project pipeline"]
$867,780,392 value mined (gross earnings) per year at current prices
$737,613,333 Nautilus share, assuming current 15% PNG buy-in
$607,446,274 Nautilus share, assuming PNG additional buy-in to 30%
445,300,000 shares outstanding
$1.66 per share first year gross earnings per share for PNG 15%, $1.36 per share for PNG 30%
12.5 Price/Earnings (PE) multiple, based on current GDXJ (Jr. Miners ETF) PE
$20.75 price per share based on first full year of Sol1 production for PNG 15%, $17 for PNG 30% (offset by additional cash to be received from PNG)
So my definition of "roof" at this time is between $17 and $21 per share, depending of PNG opts in for the additional 15%.
Of course, it's entirely possible that the PE multiple will surge well past 12.5, but if so that'll only be frosting on the very rich cake. Additionally, with metals prices at generational lows and junior miners all but left for dead by the market, the price surge could easily hit $40.
And please double check my math so Monk won't accuse me of pumping!