This is the nature of exploration and for that matter research...

This is the nature of exploration and for that matter research and all investigation. You seem to have a naïve understanding of the nature of exploration. There are so many cases where exploration at first yields no result. Then after millions have been spent there MAY BE a result. Get real about this situation.
Certainly money has been spent on Promontorio, and eventually it may sold to another company, who may or may not create a profitable mine from it. The epithermal veins have potential, and if more of these can be found then there is a real possibility of a mine. However the metallurgy at these veins had problems, I think it was arsenic.