Enhanced Recovery

The end of life for heaps and dumps is the perfect time to consider an enhanced recovery program to draw down the remaining metal inventory in stock, whether it is gold, copper, silver, nickel, uranium, or other mineral resource that is leached with a reagent.  Through our numerous investigations and characterization programs of heaps, we have seen that they can be quite dry or underleached over large swaths of the pad, equating to a significant resource that can be exploited for recovery.  Unfortunately, continued surface irrigation is unlikely to change that, and we recommend a subsurface leaching program for the enhanced recovery of the resource.


In most cases, at the end of their life, heaps contain significant metal inventory that can only be extracted through enhanced metal recovery methods.

HGI’s Geotection and Mobile Solutions Lab used to monitor and validate enhanced recovery subsurface leaching on a copper heap leach pad.


A sustained enhanced recovery program can yield an additional 2 to 5% of total metal recovered in just a few years, with a significant return on investment.  To ensure that target recovery estimates are reached, HGI has developed a set of monitoring and validation tools that can track the success of subsurface leaching.  The results of our monitoring and validation efforts have been published in scientific papers and presented at national meetings.  By bringing HGI into your enhanced recovery project, we can help to get you up and running in a shorter period of time while reducing your risk of project failure.


Advances in geophysical technologies have created new opportunities for enhanced secondary metal recovery in the mining industry.


To begin a subsurface leaching program, we recommend that you first consider geophysical heap characterization. The pre-injection characterization allows us to investigate areas of excessive saturation that may lead to slope failure or areas that potentially hold a significant amount leached metal that simply needs drained. We can also supply drilling support to validate geophysical targets and build an inventory model for resource evaluation. From these results, we will design a well field for injection or rinsing, suggest a monitoring program to capture relevant metallurgical and hydraulic parameters, and build a resource recovery model that provides economic validation to the project.


Monitoring and validation of an enhanced subsurface leaching project to capture metal inventory in the heap leach pad. Subsurface leaching through injection can increase metal production