International Journal of Mining and Geo-Engineering

International Journal of Mining and Geo-Engineering

Geometry determination of galleries and pillars in Chehel Koureh copper mine, Iran

Document Type : Research Paper

Authors
Masoud Cheraghi Seifabad
Yousef Mirzadeh Koohshahi
Ali Bameri
Department of Mining Engineering, Isfahan University of Technology, Isfahan, Iran
10.22059/ijmge.2021.283899.594819
Abstract
Chehel Koureh mine project is located 110 km NW of Zahedan in the southeast of Iran. Due to the great depth of ore deposits, the underground exploitation method was chosen. In this research, the geomechanical parameters were obtained using in situ tests and empirical formulas. The non-pillar continuous mining method (NPCM) was selected as the most appropriate method considering the shape of the ore body and rock mass strength conditions. As the rock mass is fractured and has semi-continuum characteristics, the stability analysis of the shape dimensions was carried out using FLAC 3D software. In the proposed method, a cylindrical pillar with a height of 3.8 meters was located above the stope. For the safety of the drilling machine room and stope roof, height accuracy was required. Five different pillar diameters (i.e., 3, 3.2, 3.4, 3.6, and 3.8 m) were analyzed by considering the critical height and plastic zone created around the pillar. For these five diameters, only the pillar with a diameter of 3 meters had a supercritical height. It was observed that for the pillar with a diameter of 3.8 m, no plastic zone was created and the safety factor for this pillar was obtained 1.11. Due to the restrictions for the application of the proposed mining method i.e. NPCM in Iran, the Miami method was considered as the alternative mining method applicable to the Chehel Koureh copper deposit. Then, the suitable dimensions for stope and pillar were determined by the same software. In the Miami method, there were three spans and two pillars at each stope before the recovery of pillars could be undertaken. The pillars with three widths of, i.e., 5, 6, and 8 meters were studied for the stability analysis. The results demonstrated that a plastic zone was not created only around the pillar with a width of 8 meters, and the safety factor for this pillar was obtained to be 1.56.
Keywords
Chehel Koureh mine
Non- Pillar Continuous Mining Method (NPCM)
Miami method
Safety factor
  • Tesarik, D.R., Seymour, J.B., &Yanske, T.R. (2003). Post-failure behavior of two mine pillars confined with backfill , International Journal of Rock Mechanics & Mining Sciences., 40 (0), 221–232.
  • Bogert, H.,Jung, S.J., & Lim, H.W. (1997). Room and pillar stope design in highly fractured area, International Journal of Rock Mechanics & Mining Sciences., 34 (0), 145-159.
  • Li, Z., Liu, H., Dai, R., & Su, X. (2005). Application of numerical analysis principles and key technology for high fidelity simulations to 3-D physical model tests for underground caverns, Tunneling and underground space Technology., 20 (0), 390-395.
  • Hammett, R.D., Hoek, E. (1981). Design of large underground caverns for hydroelectric projects with particular reference to structurally controlled failure mechanisms. ASCE Spring Convention, New York Session on Rock Mechanics of Large Hydro Projects.
  • Martin, C.D ., Kaiser, P.K., & Christiansson, R. (2003). Stress, instability and design of underground excavations., International Journal of Rock Mechanics & Mining Sciences., 40 (0), 1027-1047.
  • Stille, H., Palmstrom, A. (2003). Classification as a tool in rock engineering”, Tunneling and Underground Space Technology., 18, 331-345.
  • Hudson, J.A. Feng, X.T. (2007). Updated flowcharts for rock mechanics modelling and rock engineering design, International Journal of Rock Mechanics & Mining Sciences., 44 (0), 174-195.
  • Jing ,L.,Hudson, J.A. (2002). Numerical methods in rock mechanics, International Journal of Rock Mechanics & Mining Sciences, 39 (0), 409-427.
  • Palassi, M., Asadollahi, P. (2012). Development of plastic zone around underground excavations, University of Tehran.
  • Kavoshgaran Consulting Engineering Company. (1996). Chehel Koureh mine design.
  • Ghasemi, E., Shahriar,K., & Sharifzadeh,M. (2012). A new method for risk assessment of pillar recovery operation, Safety Science., 50 (0), 579–585.
  • Wang, S. Y., Sloan, S. W., Huang, M. L., & Tang, C. A. (2011). Numerical Study of Failure Mechanism of Serial and Parallel Rock Pillars, Rock Mech Rock Eng., 44 (0), 179–198.
  • Hoek, E. Brown, E.T (1997). Practical estimates of rock mass strength. Int. J. Rock Mech Min Scin, 34(8), 1165-86.
  • Sonmez, H., Ulusay, R. (1999). Modifications to the geological strength index (GSI) and their applicability to rock slopes. Int. J. Rock Mech Min Scin, 36(8), 743-760.
  • Hoek, E. Brown, E.T. (1980). Underground excavations in rock. Inst. Min Metall, Lonodon, Uk.
  • Yudhbir, A., Lemanza, W., & Prinzl F. (1983). An empirical failure criterion for rock masses. In: Proceedings of the fifth international congress on rock mechanics, Melbourne, Australia.
  • Ramamurthy, T. A. (1986). Stability of rock mass. 8 th Annual lecture. Indian Geotech. J. 1-74.
  • Kalamaris, G. S., Bieniawski, Z. T. (1995). A rock mass strength concept for coal incorporating the effect of time, Proceedings of the eight international congress on rock mechanics, Rotterdam: Balkema.
  • Shoerey, P.R. (1997). Empirical rock failure criteria, Rotterdam : Balkema.
  • Trueman R. (1988). An evaluation of strata support techniques in dual life gate roads. PhD Thesis. Univ Wales, Cardiff. Uk.
  • Aydan, O. Dalgic, S. (1998). Prediction of deformation behavior of 3 lanes Bolu Tunnel through squeezing rocks of North American Fault Zone (NAFZ), Proceedings of the regional symposium on sedimentary rock engineering, Taipei, Taiwan.
  • Hoek, E. Carranza-Torres, C.T., & Corkum, B. (2002). Hoek-Brown failure criterion-2002 edition. Proceedings of the 5th North American Rock Mechanics Symposium, Toronto, Canada.
  • Bieniawski, Z.T. (1978). Determining rock mass deformability: experience from case histories,” Int. J. Rock Mech Min Scin Geomech Abstr. 15 (0), 237-247.
  • Verman, M.K. (2018). Rock Mass-Tunnel Support Interaction Analysis. Available online: http://shodhbhagirathi.iitr.ac.in:8081/xmlui/handle/123456789/1322.
  • Mitri, H., Edrissi, R., &  Henning, J. (1994).  Finite-element modeling of cable-bolted stopes in hard-rock underground mines, ” at SME annual meeting, New Mexico, Albuqueurque, USA.
  • Hoek, E., Brown, E.T. (1997). Practical estimates of rock mass strength. Int. J. Rock Mech Min Scin, 34(8), 1165-86.
  • Read, S. A. L., Richards, L. R., & Perrin, N. D. (1999). Applicability of the Hoek-Brown failure criterion to New Zealand greywacke rocks, Proceedings 9th International Society for Rock Mechanics Congress, Paris, France.
  • Ramamurthy, T. A. (2001). Shear strength response of some geological materials in triaxial compression, Int J Rock Mech Min Sci 2001, 38 (0), 683-97.
  • Ramamurthy, T. A. (2004). Geo-engineering classification for rocks and rock masses, Int J Rock Mech Min Sci 41 (0), 89-101.
  • Hoek, E., Diederichs, M. S. (2004). Empirical estimation of rock mass modulus, Int. J. Rock Mech Min Scin, 43(2), 203-215.
  • Itasca Consulting Group. (2009). FLAC3D, Fast Lagrangian Analysis of Continua in 3 Dimensions, version 4, User's Manual.
  • Deng, J., Yue, Z.Q., Tham, L.G., & Zhu, H.H. (2003). Pillar design by combining finite element methods, neural networks and reliability: a case study of the Feng Huangshan copper mine, China,International, Journal of Rock Mechanics & Mining Sciences., 40 (0), 585–599.
  • Esterhuizen, G.S., Dolinar, D.R., & Ellenberger, J.L. (2011). Pillar strength in underground stone mines in the United States, International Journal of Rock Mechanics & Mining Sciences., 48 (0), 42–50.
  • Hill, D. (2005). Coal Pillar Design Criteria for Surface Protection, Coal Operators, Conference, University of Wollongong & the Australasian Institute of Mining and Metallurgy., Austarlia
  • Hill, D. (2005). Coal Pillar Design Criteria for Surface Protection, Coal Operators, Conference, University of Wollongong & the Australasian Institute of Mining and Metallurgy, Austarlia.
International Journal of Mining and Geo-Engineering
Volume 56, Issue 2
Spring 2022
Pages 139-150