Abstract
It is advisable to conduct mining operations in the conditions of the ultimate state of the opened massif with an increase in the pit wall slope angles below the limit of effective use of combined motor-conveyor transport in the cleaning-up zone of deep and ultradeep open pit mines to the final depth. Such a design of the pit walls is achieved when mining benches from top to bottom within the boundaries of steep-slope layers with the use of in-bench loaders in the cleaning-up zone. The conditions for the occurrence of irreversible shear deformations in rock layers and the position of the potential sliding surface with an increase in the pit walls slope angle of steeply inclined layers in the conditions of the ultra-deep Kachar iron ore open pit mine to critical values are established. It is advisable to use skips as the load-carrying body of the in-bench loader, the design of the supports of which allows it to be built with a lifting height of more than 30 m with the possibility of moving along the pit wall with variable berm elevations. The main provisions on the selection and justification of the expediency of using a loading device for operation in the deep zone are formulated based on the differentiation of the application zones of cyclic (motor transport) and cyclic and continuous method (combined motor-conveyor transport). In particular, the total costs of transporting rock mass according to the new scheme of combined in-pit transport with the use of a loading device for operation in the deep zone should be less than the costs of transportation according to existing or traditional schemes.