Improvement of the stoping technology in mining magnetite quartzite by underground methods

Abstract

The ore deposits in Kryvyi Rih iron ore basin are mined using bulk ore and overlying rocks caving systems. These mining systems have a significant drawback, namely a 2 – 5% reduction in the iron content of the mined ore mass when mining rich ores and up to 15% when mining poor ores. Current technological solutions enable improvement of ore extraction values while increasing economic costs by 15 – 20%. Therefore, the present article proposes a technological solution that will improve extraction values for poor ores. The study conducted results in determining the optimal distance between drawpoints of the receiving level and substantiates location of additional workings in the footwall, which reduces ore losses and increases ore mass extraction values. The proposed technological solution will reduce ore losses by 10 – 15% of the standard losses and increase ore extraction values by 5 – 15%, while reducing iron content by 5 – 7% of the initial one. Thus, the study conducted proves that the use of an additional level located 30 – 35 m above the main receiving level allows reduction of ore losses from 27.39% to 21.19%, and the iron content in the extracted ore mass – by only 3% instead of 12%.