An open pit mine is an excavation made at the surface of the ground to extract ore throughout the life of the mine. Large quantities of waste rock must be excavated and relocated to access and mine the ore deposit. The planning of an open pit mine aims to exploit the mineral deposit at the lowest cost while maximizing profits, through optimizing the physical design and scheduling of ore and waste extraction. Ore and waste materials are removed in successive layers called benches, with several benches potentially in operation simultaneously at different elevations in the open pit mine.

1. Open pit mining

2. Open pit Surface Mine

3. Surfase mine Fig. 1, above shows an illustration of a Open Pit Surface Mine. The definition of a open pit mine is "an excavation or cut made at the surface of the ground for the purpose of extracting ore and which is open to the surface for the duration of the mine’s life." To expose and mine the ore, it is generally necessary to excavate and relocate large quantities of waste rock. The main objective in any commercial mining operation is the exploitation of the mineral deposit at the lowest possible cost with a view of maximizing profits. The selection of physical design parameters and the scheduling of the ore and waste extraction program are complex engineering decisions of enormous economic significance. The planning of an open pit mine is, therefore, basically an exercise in economics, constrained by certain geologic and mining engineering aspects.A bench may be defined as a ledge that forms a single level of operation above which mineral or waste materials are mined back to a bench face. The mineral or waste is removed in successive layers, each of which is a bench. Several benches may be in operation simultaneously in different parts of, and at different elevations in the open pit mine.

4. Operation open pit mining pic