Welcome to an in depth discussion regarding in situ leaching and what it might mean to the future of mining.  Why don't you begin by reading my article at Mining.com here:

http://www.mining.com/web/in-situ-copper-leaching-is-a-proven-technology/

Why Copper?

In situ leaching has likely been around for thousands of years in small scale applications dating back to Roman times.  But it did not become prominent as large scale mining technique until the Uranium industry embraced it starting in the 1950's.

Copper oxide minerals in particular were found to be leachable by sulphuric acid in large scale applications with the advent of the heap leaching system.  As copper oxide minerals such as chrysocolla, and carbonates such as malachite and azurite are readily leachable with sulphuric acid the copper mining industry saw a boom in copper oxide heap leaching starting in the 1960's.

So if copper oxides are readily leachable and the Uranium industry found ways to use in situ leaching it was time to put the two together and use the in situ leaching method to extract copper directly from the copper ore.

Getting the Solution to the Copper Minerals

Can you use in situ leaching on your deposit?  If the deposit has a leachable mineral like copper from a copper oxide mineral then the next issue is getting the leach solution to the mineral.  Heap leaching relies on moving the material and breaking it up to put on a heap.  This gives easy access for leaching solution to access the minerals.  But if you are using in situ leaching then you need to get the solution to the minerals without moving the minerals.

Clearly you will need a highly fractured rockmass for the process to even begin.  It will need to be permeable enough to allow solutions to flow through it at an economical rate.  Around old mine workings it may be possible to apply sulphuric acid directly on the ground and allow it to seep into the ground and potentially collect it from underground workings.

However, it may be more effective to drill wells into the rock to target specific locations and to get beneath any waste rock that is on the surface.  With the presence of wells then there is also the opportunity to use some of those wells for extracting the pregnant leach solution by pumping it back to surface.  You would then have a "well-to-well" in situ leaching operation.

Expected Production Rate

One of the enormous benefits of the in situ leaching method is the highly positive cash flow it generates.  Unlike typical mining operations that are capital intensive and then remove a lot of waste in the first years, with in situ leaching you will be producing copper earlier and receiving the highest production rate right at the beginning.  From the data that a few operations have gathered and from laboratory testing it is expected that recovery happens in the first 4-5 years.  Of that, the first year can produce nearly 50% of all the copper that the deposit can yield.

Ultimate Recovery

The ultimate recovery rate depends on a number of factors such as type of mineralization, location of minerals on fracture surfaces, permeability of the rockmass, gangue minerals, deposit geology, and environmental issues.  What has been demonstrated is that anywhere between 50% and 100% of the acid soluble copper will be recovered.  Each individual deposit will need to perform detailed geology, hydrology, and geochemical testing to determine what the ultimate recovery will be in their instance.

Economics

The beauty of in situ leaching is the low, low cost both in capital expenditure and operations.  Since SXEW process is used for making nearly pure copper the operating cost can be expected to be in the lowest quartile of all copper mining operations.  It is further improved by needing a much smaller labour force and few pieces of heavy equipment to maintain.

Capital costs consist of an SXEW plant (not needed if already present at the operation), drill rigs (may be outsourced), pumping equipment, piping, and electrical infrastructure.  This is clearly much less than a typical mining operation that has a fleet of shovels and trucks to buy and maintain.

Links to Other Documents:

I have found a few documents that the reader might wish to investigate to further knowledge on in situ leaching.

Recovery of Copper by Solution Mining Methods

In situ leaching wellfield design at San Manuel

in situ recovery described by Excelsior Mining

san manuel 1999 ore reserves report draft

Fluid flow mapping at a copper leaching operation

In-situ-recovery-an-alternative-to-conventional-methods-of-mining

ni-43-101-florence-copper-pre-feasibility-study

Gunnison Project PFS_2_14_14