A Case Study Of Open Pit Copper Mine Design And Optimisation

Open pit mining is a form of surface mining in which excavation is done on the surface of the land to remove ore or waste. This process result in a pit which extends in both width and depth until mining operation is terminated. In modern day mining, the final shape of the mine is determined by the mine planners prior to the start of the mining operation. However, it should be noted the final shape of the mine may change as the mining proceeds. These changes occur as a result of changeable geological properties of rock mass, irregular nature of grade distribution, varying economic parameters and a series of nonlinear dynamic problems. These possess challenges in the development of an optimal boundary and subsequently affect the amount of waste to be removed to access the ore. In order to minimise the amount of waste stripped and concept of pit optimization has become an important and integral step of open pit design.This paper made used of mining software applications to achieve an optimal pit design. A three-dimensional geological block model was developed with Surpac. Several design constraints such as geometric of the slope angle, time value, current ore market price and varying slope angle based on rock type were considered to develop an optimal pit design using whittle as a dynamic mining optimisation software.A copper mine was used as a case study and the above design techniques were implemented to produce an optimal design that is safe, realistic and economically valuable. When compare to a non-optimal design, the result shows an overwhelming improvement of the overall stripping ratio of the optimal design pit.