You might want to consider flotation to recover your copper first before leaching, what type of copper do you have? Chalcocite or chalcopyrite? If your gold is associated with the pyrite then you can depress it and flot the copper then leach. But more details of the type of ore you are treating and the circuit configuration will help to determine the best process to use.

How much is the copper in your feed? 

Google benzotriazole, copper corrosion inhibitor.

As pointed out, removal of the copper is the best solution prior to leaching if possible.  There are other issues as well related to gold recovery - if you are using carbon or Merrill Crowe the copper will show up in the final gold bullion.  If you are using carbon adsorption you can raise the pH in the leach to prevent/reduce adsorption.

Depending on the Cu mineral you could leach the ore first with acid to remove the copper then filter and wash.  What is the mineralogy of the ore?  How are you leaching it - tanks, heap....

Regards

Todd

I am currently running a plant processing a gold copper ore.its true that i have high CN concentration during leaching however im recovering my copper after leaching. I did pilot plant tests witj flotation before and after leaching and realised that for my situation i would float my copper after leaching.before leaching i realised that flotation reagents are carbon foulants and i had to do due diligence on my carbon regeneration.so i chose to put flotation of my copper aftet leaching.however i have to do cyanide destruction through blowing sulfur dioxide via pipes.CN is a coppee depressant.my advice is see what works for you..if you  want to make extra dollar with the copper is suggest floating it after leaching.if you chose to float first depress gold with sodium hydrogen sulfide then proceed to leaching.hope i have helped

It is best to determine the Cu minerals. Cu minerals that are CN soluble.