Figure 7.1. Open pit and underground overlap Table 7.1. General information on old chambers

The main problems associated to the simultaneous open pit and underground exploitation at Michilla mine are listed below.

7.1. Dilution

This problem will appear in the drilling and blasting operations. Consequently, open pit blasting against filling of the chambers will be avoided. Instead, a recovery of the filling will be carried out first to avoid dilution that may jeopardize the economy of the project.