Abstract
Purpose. Determining the actual dimensions of the protecting and crown pillars of ore bodies by seismic survey and assessing the possibility of rock mass collapse and fracturing at the lower levels of the Zhairemskoye field. Methods. An integrated approach is used, which involves the analysis of complete ore bodies development during the combined mining. To determine the geological strength index (GSI) and rock mass rating (RMR), the mass structure is studied, as well as the survey is executed of rock fracturing on the contours of mine workings at levels of +288, +240, +192, +144 m. In addition, the physical and mechanical properties of rocks are refined using the RocLab software. Using the numerical modelling of the self-caving process, when mining the protecting and crown pillars, the processed results of numerical modelling are analysed and the possible zones of the mass deformation are assessed based on the Phase2 software. Findings. It has been determined that during the mining of ore bodies 4 and 6, protecting pillars between the quarry and the underground mine, crown pillars between the levels up to the level of +144 m, the rock displacements are possible along glide surfaces. It has been revealed that the haulage workings of levels +240 and +192 m fall into the zone of possible displacements influence, and the rock pillar between ore bodies 4 and 6 will be exposed to inelastic deformations during the mining of crown pillars to the level of +144 m. It has been found that after the crown pillar development between the levels of +240 and +192 m for ore body 6, the rock pillar destructions are possible between ore bodies 4 and 6, since during the modelling, displacements of more than 2 mm are observed. In this case, the destruction processes are possible in the rock pillar upper part. Originality.A geomechanical assessment of the rocks tendency to caving is given and problem areas of stability during the mining of ore bodies 4 and 6 in the Zhairemskoye field are identified. Practical implications. The stable parameters of protecting and crown pillars have been substantiated, which is an important aspect in the design/efficient technology of mining the contiguous ore bodies. Keywords: engineering seismic, ore body, pillar, level, iron, manganese
Highlights
IntroductionWhen mining the deposits by a combined method, natural and technogenic reserves (up to 15-20% of the peripheral reserves volume) usually remain in the bowels of the Earth, which are not included in the mining schedule
The Zhairemskoye field is mined by a combined method of mining
It has been found that after the crown pillar development between the levels of +240 and +192 m for ore body 6, the rock pillar destructions are possible between ore bodies 4 and 6, since during the modelling, displacements of more than 2 mm are observed
Summary
When mining the deposits by a combined method, natural and technogenic reserves (up to 15-20% of the peripheral reserves volume) usually remain in the bowels of the Earth, which are not included in the mining schedule. These are the pillars left at the border of the quarries to separate surface and underground mining operations and to maintain the walls in a stable state [1], [2]. Despite the broken state and complex mining conditions, they can be an object of development in terms of their vo-lumes and content of useful components [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
