Your NPV still looks pretty high at $20/oz share price I think you are using a longer time horizon.
Let use some figures from previous presentation which states that FCF of $40m pa at 2m oz production target at $32/oz silver price. Assume 6 year mine life based on current indicated JORC resource. Assume 40m capex, latest presentation states higher capex range, but I know that MRP has already committed to some sunk costs. At discount rate of 10%., we get $128m NPV and IRR of 79% and payback within a year. So the value is ~ 50 cent per share.
But this is unrisked NPV - there is a funding issue overhanging MRP and this needs to be derisked so I reckon apply 50% subjective risked factor. So I reckon current value to shareholders of the Nimbus mine is around 25 cents when silver price return to $32/oz. Of course we haven't quantified the upside in FCF with the gold credits from Boonara.
At the moment silver is oversold as a result of de-escalation of the Syria military strike. But latest reports indicate China manufacturing is better than expected, so not such a hard landing. A buoyant China manufacturing bodes well for silver. We should see silver price trending back up soon, positive for MRP holders.
MRP Price at posting:
28.0¢ Sentiment: Buy Disclosure: Held