When looking at recovery methods for a new mine your first approach is to see what methods are being used by other mines nearby.
Go and have a talk to the operators of these mines and see what sorts of recoveries they are getting.
Generally you look at doing the cheapest methods (gravity) first up.
See what recovery you get and what gold levels are in the gravity tails.
Secondly look at a float test to see if the gold is in the sulphide fraction, again see what gold levels are in the float tails.
Having done the above tests, you are now into the leaching options. These apply to leaching of either head ore or process tails.
The simplest is to have a nearby mine toll treat your ore.
Next is to run cyanide leaching tests.
If you do not want to or cannot use cyanide at the mine site your stated grade, very high, will allow you to transport the material very long distances to where you can get a permit or have some one else toll treat the ore.
Much depends on the ore reserves available and the possible mining rate per day.
Small reserves and/or slow throughput will put you into the hobby miner category.
The trouble with non-cyanide leaching methods is that the ones which are alkaline have other inherent problems, glossed over by their boosters, and the acid methods all require all wettable surfaces to be non metallic.
Usually the biggest problem is in the taking of representative samples of the ore for testing, it is in human nature to include the better looking ore areas rather than get truly representative samples.
Deano