ABSTRACT
In Chile, the most important copper ore deposits have been exploited under both open pit and underground methods. A number of them (Chuquicamata, El Romeral, Carmen de Andacollo, etc.) are in the final step of exploitation by any of the methods above mentioned. On the other hand, new deeper geological resources have required a shift from open pit to underground mining because stripping ratio have raised to uneconomical level, involving different mining problems. Other deposits have evolved in the opposite way, that is, from underground mining to open pit due to new shallow geological resources, which were not previously recognized for different reasons. Other deposits are exploited simultaneously by open pit and underground mining. This work presents problems related to this situation in Minera Michilla S.A. with an emphasis on geotechnical management as an important part of the mining business.
