Research Center for Geomechanics and Mining Issues, Saint-Petersburg Mining University, Saint-Petersburg, Russia:

S. V. Tsirel, Senior Researcher, Doctor of Engineering Sciences, tsirel58@mail.ru
A. A. Pavlovich, Head of laboratory, Candidate of Engineering Sciences

The article discusses pit wall stability calculation techniques. It is shown that limit equilibrium method and mathematical modeling address different ways of slope stability loss, and calculation results may sometime appreciably differ (especially in rock masses having a complex structure). The authors analyze the kinematic analysis approaches to slope stability in permafrost. The emphasis is laid on the method to select the required value of the safety factor depending on various concurrents, including essentially different estimates of allowable risk for people and equipment. It is suggested to account for both determinate time of pit wall life and stochastic components governed by the degree of knowledge on the structure and properties of the pit wall rock mass, errors of patterns of calculation, variability of rock properties etc. A detailed discussion is devoted to the development of a regulatory document on determination of slopes for pit walls and dumps in open pit mines under planning and in operation, and to the information contents of this document. It is proposed that the new regulations are composed of three basic parts – general requirements to studying and estimating pit wall parameters; calculation standards; and calculation rules for the transition stage when calculations performed in accordance with the old codes are checking but not unique. Furthermore, the article points at the need to correct the rules of observation over state of pit walls and dumps using the modern tolls of the deformation, hydrogeomechanical and geophysical monitoring.

1. Ericsson M., Larsson V. E&MJ's annual survey of global mining investment. Engineering & Mining Journal. 2013. Vol. 214, No. 1. pp. 28–33.
2. Ilin S. A., Kovalenko V. S., Pastikhin D. V. Open method of mining: opportunities and ways. Gornyi Zhurnal. 2012. No. 2. pp. 37–40.
3. Methodical regulations for definition of edge slope angles, bench slopes and dumps of constructed and exploited pits. Leningrad : VNIMI. 1972. 166 p.
4. Rules of provision of slope stability on coal cuts. Saint Petersburg : VNIMI, 1998. 208 p.
5. Zoteev V. G., Zoteev O. V. About the necessity of improvement of legislative and regulatory frameworks for geomechanic provision of open-cast mining. Gornyi Zhurnal. 2010. No. 1. pp. 66–68.
6. Pustovoytova T. K., Mochalov A. M., Gurin A. N. Improvement of methods of calculation of slope stability. Collection of scientific proceedings “the 70-th anniversary of VNIMI”. Saint Petersburg : VNIMI, 1999. pp. 187–194.
7. Mochalov A. M., Morozov K. V., Norvatov Yu. A., Ilin M. D., Guin K., Ogorodnikov S., Braun M., Makkraken A. Comparison of Russian and international practices of analysis of pit side slopes stability. Materials of All-Russian scientifi c-technical conference with international participation “Deep open pits”. Apatity : GoI KNTs RAN, 2012. pp. 340–352.
8. Mochalov A. M., Ishutin S. A., Pavlovich A. A., Sapachev R. Yu. Evaluation of the stability of slopes with using native and foreign software. Zapiski Gornogo instituta. 2012. Vol. 199. pp. 219– 226.
9. Tonderai Chiwaye H. A comparison of the limit equilibrium and numerical modeling approaches to risk analysis for open pit mine slopes : Dissertation for to degree of Master of Science in Engineering Johannesburg. University of the Witwatersrand, 2010. 145 p.
10. Galustyan E. L. Geomechanics of open-cast mining : reference book. Moscow : Nedra, 1992. 272 p.
11. Sapozhnikov V. T., Kim D. N., Afanasev B. G. Nature of deformation of Ural cut edges in near-cutoff state. Sbornik trudov VNIMI. 1986. pp. 64–71.
12. Fisenko G. L. Stability of pit and dump edges. Moscow : Nedra, 1965. 378 p.
13. Kocharyan G. G. Spivak A. A. Hierarchy of structural and geodynamic parameters of the Earth’s crust. Geologiya, inzhenernaya geologiya, gidrogeologiya, geokriologiya. 2002. No. 6. pp. 537–550.
14. Lukk A. A., Deshcherevskiy A. V., Sidorin A. Ya., Sidorin I. A. Variations of geophysical fields as a display of determined chaos in fractal medium. Moscow : OIFZ RAN, 1996. 200 p.
15. Sainoki A. Dynamic Modelling Of Mining-Induced Fault-Slip : A thesis … of Doctor of Philosophy in Mining Engineering. Montreal : McGill University, 2014. 238 p.
16. Read J., Stacey P. Guidelines for open pit slope design. Australia : CSIRО, 2009. 496 p.
17. Kozhukhovskiy A. V., Zavyalov A. A., Kozyrev A. A., Seryy S. S., Dunaev V. A. Innovation technologies of monitoring and forecasting of the stability of the deep open pit edges. Gornyi Zhurnal. 2012. No. 10. pp. 29–35.
18. Mochalov A. M. Calculation of stability of two-dimensional profi le slopes in homogeneous medium. Sbornik trudov VNIMI. 1976. No. 100. pp. 116–128.
19. Hoek E., Caranza-Torres C., Corcum B. Hoek–Brown failure criterion. Proceedings of the North American Rock Mechanics Society. Mining Innovation and Technology. Toronto, 2002. pp. 267–273.

20. Bieniawski Z. T. Engineering rock mass classifications. New York : Wiley, 1989.
21. Temporary methodical regulations for control of pit edge stability in non-ferrous metallurgy. Moscow : Unipromed, 1989. 128 p.
22. Mochalov A. M. Assessment of stability of pit edges by the observed deformations. Improvement of calculation methods for movement and deformations of rocks, facilities and cut edges during the coal layer mining in complex mining-geological conditions. Saint Petersburg : VNIMI, 1985. pp. 42–52.
23. Hormazabal E., Rovira F., Walker M., Carranza-Torres C. Analysis and design of slopes for Rajo Sur, an open pit mine next to the subsidence crater of El Teniente mine in Chile. Proceedings of Slope Stability 2009, November 9–11. Santiago : Universidad de los Andes, 2009.
24. Taseko mines limited new prosperity gold-copper project. Preliminary pit slope design. Knight Piesold consulting, 2012. 78 p.
25. Rybin V. V., Zhirov D. V., Melikhova G. S., Klimov S. A. Complex method of engineering-structural investigations and monitoring of geomechanical state of rock massif for design and exploitation of deep pits. Modern tectonophysics. Methods and results. Moscow : IFZ, 2011. pp. 100–109.
26. Tsirel S. V., Zuev B. Yu., Pavlovich А. А. The infl uence of earthquakes on open-pit slope stability. International Journal of Geosciences. 2012. Vol. 3. pp. 799–808.
27. Guidance for observation of edge, slope and dump deformations on pits and for development of operations for their provision and stability. Gosgortekhnadzor SSSR 21.07.1970. Leningrad : VNIMI, 1971. 236 p.
28. Methodical regulations for observation of edge, slope and dump deformations, interpretation of their results and stability forecast. Ed.: G. L. Fisenko. Leningrad : VNIMI, 1987. 116 p.
29. Kantemirov Yu. I. Space radar monitoring of shifts and deformations of earth surface and constructions. Experience of «SOVZOND» company. Vestnik SibGAU. 2003. No. 5. pp. 52–54.
30. Galperin A. M., Kutepov Yu. I., Krupoderov V. S., Kiyanets A. V. Hydrogeomechanical monitoring and mastering of technogenic massifs on mining enterprises. Gornyy informatsionno-analiticheskiy byulleten. 2012. Special issue No. 1. Proceedings of the scientific symposium «Miner’s week-2012». pp. 44–57.
31. Malovichko D. A., Linch R. E. Microseismic monitoring of pit edges. Gornoe Ekho. 2006. No. 2 (24). pp. 21–30.