Ok, tell me how many millions of tons of equipment and how many gigawatts of power we will need to process out large quantities of these resources from razor s

Ok, tell me how many millions of tons of equipment and how many gigawatts of power we will need to process out large quantities of these resources from razor sharp sand, and how many trillions of dollars it will cost to build it on the moon? We can process gold out of seawater, so why do we dig far into the earth to find veins of gold?