Vertical Pit Mining
Vertical pit mining is a technique developed as an alternative mining method for the exploitation of ore bodies, from surface to approximately 200m. vertical pit mining is suited for small, vertical, massive orebodies, where high strip ratios could render the operation uneconomical. In this method systematic anchoring of the in situ rock mass together with the installation of wire mesh and shotcrete is used to prevent small-scale raveling and spalling of the sidewalls.
Hoisting of the ore is carried out either by a vertical A Frame hoist at the crest of the pit, which requires tramming of ore at the base of the pit to the hoist. Alternatively, a Blondin Cableway system, which allows for loading of kibbles at any location within the pit, negating the need for a tram to the hoist located on the side of the pit, can be utilized. This technique has been successfully applied to the mining of a chrome deposit in Zimbabwe to a depth of 95m and a Kimberlite pit in West Africa.