ERT Surveys to Detect PLS Levels in Heap Leaching Pads: Sarcheshmeh Copper Mine Case Study

In this paper we present electrical resistivity tomography (ERT) surveys performed on heap leaching pad no. 2 at Sarcheshmeh copper mine which is one of the largest copper deposits in the world. Heap leaching no. 2 arrived at its maximum height a few years ago and acid irrigation was then ceased on top of this heap leaching pad. There was an urgent need to displace this heap leaching pad due to the existence of the economic deposit underneath. Although the leaching process was ceased for almost four years at the time of this study, there was still a significant rate of pregnant leach solution (PLS) exiting at the bottom of the heap. Therefore, it was necessary to explore the PLS level within the heap in order to safely design the heap displacement. Due to time and space limitations, two ERT profiles were measured with the pole-dipole electrode configuration with unit electrode spacing of 20m. One profile was repeated with the electrode spacing of 10m as well to increase the resolution. The results detected the PLS level at a depth of about 20m in the study site.