RE:Where did the silver come from?Thanks Retiredgeo.
My understanding is that the remobilization of silver from a porphyry deposit may not necessarily deplete the deposit of copper below. While some silver may be removed from certain zones within the deposit and redistributed elsewhere, the overall copper content of the deposit may remain relatively unchanged.
Additionally, to add to your point, the redistribution of metals within the deposit can lead to the formation of higher-grade ore zones in some areas, potentially increasing the economic value of the deposit.