Development of highly efficient technologies for extracting rich iron ores at deep levels of Kryvbas mines

About half of the rich iron ore mined in the Kryvbas mines is extracted applying various types of sublevel caving systems. At the same time, ore haulage in the mining panels is carried out exclusively by scraper equipment, which does not meet modern requirements in terms of miners’ working conditions, productivity and safety. The aim of the work was to develop more efficient flowsheets for the extraction of rich iron ores applying the sublevel caving system. This was achieved primarily through the employment of self-propelled underground loaders, haulers and dumpers (LHDs) and other technical solutions for ore. The new flowsheets for the development of iron ore deposits applying the sublevel caving system based on the use of the mentioned self-propelled machinery for haulage are proposed. This is achieved by using, in addition to the main draw level, where only this self-propelled machinery operates, an additional draw level with the use of scraper equipment, for which the drill drift is reused. This ensures more intensive mining of panels, thereby reducing the cost of maintaining workings and improving ore extraction rates. Another option, designed for mining deposits with a thickness of up to 30-35 m, involves application of inclined compensation rooms, which makes it possible to create rooms of sufficient volume even in low-strength ores, as well as combined ore haulage by self-propelled LHDs and scraper equipment. To increase the efficiency of the self-propelled LHDs, productivity of which is significantly higher than that of scraper equipment, it is possible to employ one self-propelled machine for the simultaneous haulage of ore from two adjacent panels. Thus, the main advantages of the proposed mining system options are an increase in the intensity of panel mining, a significant reduction in the loss of ore on the footwall of the deposit, and the possibility of employing self-propelled machinery in the conditions of Kryvyi Rih iron ore basin mines