Develop an alternate mining technology to produce ores at lesser cost from 120m deep opencast mine.
Shovel dumper combination is being currently used for excavation of ores. The lowest level of excavation is limited by allowable slope angle and ultimate pit limit. We aim to do a further excavation of up to 20 m beyond this pit limit. The problem with this is the stabilization of the pit wall which will collapse beyond 6 m excavation. Hence, it is not possible to mine ore below the ultimate pit level through open cast route.
The cost of excavation in the current method is increasing with depth because of higher excavation of Over Burden (mining waste) for mining same quantity of Ore. The current ratio of ore to overburden is 1:5. If the ore only could be excavated, or the amount of overburden could be reduced, then the cost of mining will come down significantly.
Thus, we are looking for low-cost alternate technology for the mining of ores from opencast mines keeping in mind the following aspects: