Scientific and technical problems of transition from open pit to combined technologies for raw materials mining

Abstract

In Kryvyi Rih iron ore basin, long-term and intensive mining of deposits applying open pit methods have resulted in significant areas disturbed by open pits, dumps and tailings storage facilities. Hundreds of thousands of hectares of fertile arable land are already unsuitable for agriculture and sometimes for living. Thousands of tonnes of dust from dumps and tailing ponds deteriorate the surrounding nature every year and pollute the atmosphere in mining basins. Industrial ore breaking in open pits using bulk blasting causes emissions of a significant amount of harmful dust and carcinogenic substances. The environmental situation in open pit mining areas is often close to critical. In addition, bulk blasting forms a seismic wave, which in some cases destruct civil buildings and industrial facilities. The article proposes ways of gradual transition from mining mineral deposits by open pit methods to environmentally friendly technologies of open pit-underground and underground mining. It is established that such transition is a forced and at the same time choiceless way of developing mining areas, in particular Kryvyi Rih iron ore basin. The paper notes that the main problems of this transition include geomechanical stabilization of the rock massif during construction of underground mines in areas of possible impacts of open pit fields. The paper develops the fundamental study of the problems of controlling the stress-strain state of the massif during transition from the open pit to combined technology of deposit mining. Technologies of combined mining that involve formation of a transition belt with backfilling the worked-out space with compound mixtures are studied as well. It is proved that development of theoretical foundations for controlling the stress-strain state of the massif during transition from the open-pit to combined technology of deposit mining, study and design of technological solutions that contribute to transition to open pit-underground and underground mining, is an urgent scientific, technical and practical problem of great importance.