Author 1:

Name & Surname: Koltsov P. V.
Company: Uralmekhanobr JSC (Ekaterinburg, Russia)
Work Position: Head of Pitwall Stability Laboratory
Scientific Degree: Candidate of Engineering Sciences
Contacts: e-mail: kpavel@mail.umbr.ru

Author 2:

Name & Surname: Ivanov Yu. S.
Company: Uralmekhanobr JSC (Ekaterinburg, Russia)
Work Position: Principal Researcher
Contacts: e-mail: ivanov_us@umbr.ru

Author 3:

Name & Surname: Andreeva O. N.
Company: Uralmekhanobr JSC (Ekaterinburg, Russia)
Work Position: Senior Researcher
Contacts: e-mail: golovina_on@umbr.ru

The article describes the case study of open-pit mining at the New Sibai site. The feasible patterns of extraction in walls and bottom of an open-pit mine are given. The most reasonable scheme of extraction involves sublevel caving in pit walls and wedge-outs under conditions of compression (squeezing), then in adjacent walls under additional loading and, finally, under the open pit bottom. Based on the research findings, feasibility of extraction of ore reserves in walls and bottom of Sibaisky open-pit mine depends on fulfillment of the following conditions:
- Extraction starts with underground mining in the southern and northern pit walls at a slop grade of 58°, with retaining stable openpit ramp to accessing adits;
- With another accessing scheme and the ramp operation close-down, mining of the southern and northern wedge-outs is conducted stage-wise, at a slope grade of 58°; the overburden is blasted to avoid downfall and additional load on the pit walls during undermining; deformation of upper slopes is allowed at this stage of extraction;
- Extraction of the western wall at the footwall of the deposit is to be carried out under protection of additional load produced by internal dump; from the data on the undermined slope stability, the boundary of westward mining in the southern and northern walls without additional load is substantiated;
- Extraction of the eastern wall reserves must be coordinated with the stages of mining in the adjacent walls due to enlargement of span of the wall and, thus, its decreased stability;
Since the stability of the eastern wall is worsened by deformation of the upper layers and in view of its maximum undermining (hanging wall), separate validation of mine design shall be carried out, including alternatives of additional load.
Actual state of slopes in the sites of current extraction of ore reserves in the pit walls confirms the accuracy of the performed stability validation.

1. Solovev A. A., Zobnin V. I., Ivanov Yu. S., Lukichev V. G. Vybor skhemy dorabotki Sibayskogo mestorozhdeniya kombinirovannym sposobom (Choice of the scheme of cleaning-up of Sibay deposit by combined method). Izvestiya vuzov. Gornyy zhurnal = Proceedings of Universities. Mining Journal. 2007. No. 4. pp. 13–20.
2. Pravila obespecheniya ustoychivosti otkosov na ugolnykh razrezakh: utverzhden Gosgortekhnadzorom RF 16.03.98 (Regulations of provision of slope steadiness at coal strip mines : approved by State Technical and Mining Inspectorate). Saint Petersburg : Science-Research Institute of Mining Geomechanics and Mine Surveying, 1998. 208 p. (in Russian).