Recovery of copper from heap leach residues

A process for recovering copper from heap leach residues containing residual copper, the process comprising:

• identifying a production zone within a heap of the heap leach residues for secondary leaching;
• drilling wells into the heap at locations suitable for delivering leach solution including sulfuric acid and ferric ions into the production zone;
• injecting the leach solution including the sulfuric acid and ferric ions through the wells and aerating the production zone to facilitate oxidative reactions within the production zone;
• and
• collecting effluent from the heap via drainage conduits for copper recovery from the effluent,
• wherein the leach solution is injected at a flow rate such that the drainage conduits are less than full to facilitate air entry into the production zone via the drainage conduits and aerating comprises blowing air through drainage conduits and into the production zone.