Babayants G. M., Candidate of Engineering Sciences, phone: +7 (495) 421-91-14

Searching of technical and technological solutions on replenishment of leaving capacities were activated in connection with significant exhaustion of reserves in project contours of many large open pits. One of methods is local reconstruction of near-bottom open pit zone and its transport system for the purpose of involving of additional outboard (rarely – lower-bottom) open pit reserves into open-cast-mining. This article shows two methods of combined open-cast and underground mining of steep-grade ore deposit, which were developed and offered for use. Newness of these methods is protected by authorship certificates No. 607018 and No. 690181. Schemes of opening and preparation of shaft horizons are shown together with parameters and designs of underground mining systems. According to this, stope formation is shown together with drilling and blasting breaking, ore drawing and goaf stowing. Offered designs and technologies of combined excavation of pit reserves have the following advantages:
- use of open-pit area for hole-drilling and blasting of pit ore massif;
- cylindric access chambers and circle ranges of blasting holes, providing the intensive concussion and additional destruction of blasted rock lumps;
- formation of sections from several joint worked-out chambers for storage of open pit overburden and (or) concentration wastes;

- possibility of reworking of near-bottom open-pit zone by high benches, and, if necessary, pass-by of part of open pit ore through cleaning chambers (sections).
Together with foregoing advantages of the first method, the second way of combined mining of ore deposit allows to carry out the simultaneous extraction of ore by open-cast and underground methods due to superpass opening and preparation of pit reserves for extraction. According to this, there is possible to support or increase of enterprise capacity.
This article is published in a discussion order.

1. Otkrytye gornye raboty v XXI veke (Open-cast mining in the XXI century). Gornyi Zhurnal – Mining Journal, 2009, No. 11.
2. Kaplunov D. R., Shuboderov V. N. Gornyi Zhurnal – Mining Journal, 1997, No. 8, pp. 16-18.
3. Kaplunov D. R., Leyzerovich S. G., Tomaev V. K., Sidorchuk V. V. Gornyi Zhurnal – Mining Journal, 2011, No. 10, pp. 44-49.
4. Volkov Yu. V., Sokolov I. V. Gornyi Zhurnal – Mining Journal, 2011, No. 11, pp. 41-44.
5. Sokolov I. V., Antipin Yu. G. Gornyi Zhurnal – Mining Journal, 2012, No. 1, pp. 67-71.