For late game for copper mine lvl 3 normal (600 ore/min) u can just kinda overclock for all factory to double and then 4 factory - 1 overclock item. From 600 ore to 300 Sheet

Another nice clean building, but the Smart Splitters on the left side top and bottom floors are set to Left output, which feeds into nothing. Once I went inside and switched them to right output everything worked great.