N. A. Chinakal Institute of Mining Siberian Branch Russian Academy of Sciences, Novosibirsk, Russia:

S. A. Shchukin, Junior Researcher
S. A. Neverov, Head of Laboratory, Leading Researcher, Candidate of Engineering Sciences
A. A. Neverov, Leading Researcher, Candidate of Engineering Sciences, nnn_aa@mail.ru
A. I. Konurin, Researcher, Candidate of Engineering Sciences

One of the problems in underground ore mining is ill-timed preparation of ore reserves for extraction and, as a consequence, reduction in overall efficiency of mines. In this connection, it is increasingly often attempted to replenish depleted reserves and maintain the design capacity through extraction of various-purpose pillars. Safe extraction of rib, crown and bottom pillars left after open stoping requires reduction of the dynamic events due to rock pressure, feasibility study and sound selection of mining technology and sequence. The safety constraints are the absence of the transport accesses to pillars and high probability of partial or total failure of pillars left in extremely complicated geological and geomechanical conditions, including great depths. Based on 3-D finite-element mathematical modeling in terms of thin ore bodies, the geomechanical conditions are substantiated for extraction of ore reserves from pillars depending on arrangement of orepasses and ventilation-and-service raises, as well as jointing of rock mass. The calculations have found that, given orepasses and ventilation-and-service raises are arranged in enclosing rocks, safe extraction of ore reserves from pillars is highly probable due to their high stability. In this case, the use of block caving systems and varied sequence of mining entirely meets safety requirements of stoping.

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