The in-fill holes are incredibly important because you need JORC...

The in-fill holes are incredibly important because you need JORC tonnage moved to measured and indicated status in order to declare a mining ‘reserve’. The mining reserve is necessary because it gives financiers enough confidence to decide whether or not to provide finance to the project (inferred tonnage is not accurate enough to enable project debt funding).

Before a consultant signs off on tonnage moving to reserve status, there’s also a commerciality assessment made (simply finding tonnage below the ground is not enough - you have to prove that the tonnage is commercially accessible).

This is part of the reason why projects struggle after the initial discovery, until finance and construction and production start - the initial discovery is exciting and everyone is excited, but after this, investors have short attention spans and most of the activity involves spending money to prove the project without necessarily making new discoveries.