"(we also have credits CU, PD, PG but we'll use these for mining just for simplicity)"

Actually either one of copper, platinum or paladium provides sufficient $ for operation of the mine. So two of these metals and the nickel are obtained almost for free.
Of course this neglects things like financing, tax and royalty costs etc.
If we take into account all the Noront properties then we should be near $28 per share, again this does not take into account the potential of those properties.
Therefore it is not an exaggeration to just say that we are under valued, we are under valued compared to most of our neighbours and the metal exploration segment of the markets.
So I say to all prospective investors, do not be annoyed by the continuous repetition of this 'under valued' mantra. Per LT's ( Mark) post, there IS just cause.