The solution to the problem of the placement of internal dumps in the development for forming the deep pit edges by steep dipping layers

Abstract

Purpose. The solution to the problem of the formation of internal dumps in the development of iron ore deposits and the formation of the benchof deep pits with steep dipping layers. The research methodology consists in establishing the costs of extracting, moving waste rocks from the face to the internal or external dumps with their subsequent storage during the development of steep dipping layers according to the proposed technological scheme. At working out steep dipping layers, a decrease in the distances of transportation of waste rocks from the lower horizons is achieved due to the correct placement of transport communications and the formation of internal dumps. Allocation the phases of development at the deposit allows to form the pit of a first-stage with subsequent advancement of the mining front using steep dipping layers and the formation of an internal dump. Findings. Calculations of cost were executed taking into account the proposed technological scheme of the development of steep dipping layers. The obtained calculations of the cost of preparation, extraction, transportation and placement of waste rocks in external or internal dumps made consider possible cargo flows from faces to storage. At the same time, it was taking into account the costs of the main processes without transport are constant. Transportation costs with depth increase and, accordingly, most affect the cost of waste mining. According to the presented scheme, working out steep dipping layers is carried out by diagonal blocks at the ends of the pitand longitudinal - inside its central part. Transportation of waste rocks inside the pit is carried out by dump trucks directly to external or internal dumps, as well as to transshipment points with further placement by conveyor and rail transport. The originality. The graphical dependencies of expenses on the processes of extraction of waste rocks on the hanging and lying pit edge were established. It allowed to determine the most promising directions of transportation of rocks from the face to the dumps. Practical implications. The research results allow to determine the optimal transportation schemes for waste rocks, to recommend them for implementation in deep pits that work out steep dipping iron ore deposits.