The surficial, lateral expanse and the massive nature of the Molo deposit make it suitable for open-pit mining methods. It is a typical pipe shaped and steeply dipping ore body, with an extended mineral outcrop along the strike (north-south direction) of the deposit. In this mining method, the following activities are executed:
•The land is cleared, topsoil is removed and stockpiled at designated sites for use in future land rehabilitation. Depending on the extent of the base of weathering, any further waste, or ore that can be removed by free-digging is removed and stockpiled accordingly. The topsoil is planned to be used as a berm around the pit to prevent water flow into the pit and to minimise transportation costs
•In a number of cyclic processes, the waste and/or mineralised material is drilled, charged with explosives and blasted, excavated, hauled and dumped in designated sites
•At strategically planned periods the waste around the boundary of the pit is removed in order to mine out deeper ore. The conventional open pit mining activities are carried out with small to medium sized mining equipment including 20t dump trucks, a 2 m3 excavator and an 8 m3 Front End Loader.
Using the minimum mining width of 30 m suited for the selected mining equipment and the recommended 46o slope angle, the final pit design at Molo was drafted including the following key design parameters:
- A single ramp was designed in the centre zo ........