Mining of Mineral Deposits

ISSN 2415-3443 (Online)

ISSN 2415-3435 (Print)

Flag Counter

Geotechnical modeling of the method for mining cobalt deposits at the Bou Azzer Mine, Morocco

Anas Driouch1, Latifa Ouadif1, Abdelaziz Lahmili1, Mohammed Amine Belmi1, Khalid Benjmel2

1Mohammadia School of Engineers, Mohammed V University, Rabat, Morocco

2Faculty of Sciences Ain Chock, Hassan II University, Casablanca, Morocco

Min. miner. depos. 2023, 17(1):51-58

Full text (PDF)


      Purpose. The Bou Azzer Mine encounters difficulties during cobalt mining. In order to select the optimal mining sequence with the least geotechnical stability problems, one possible variant is the cut and backfill mining method used in the Bou Azzer East area at a depth of 540 m.

      Methods. This paper presents a methodology for selecting a sequence of the cut and backfill mining method using 2D geotechnical numerical modeling, taking into account the morphological characteristics, geomechanical properties of the ore and the surrounding rocks.

      Findings. The sequences of mining with rock backfill and rock-cemented backfill show that the high principal stress (Sigma 1) is in the range of 10-153 MPa, and the safety factors are in the range of 0.63-1.89. Therefore, mining sequences with cemented backfill and under cemented backfill have a principal stress (Sigma 1) in the range of 10-112 MPa and acceptable safety factors.

      Originality. In this study, the bottom-up mining sequence with a cemented backfill is proposed for the case of low-quality serpentine footwall. This mining sequence aims to achieve good cobalt mine production and provides a safe environment for miners.

      Practical implications. In the mining industry, the choice of mining method using 2D or 3D geotechnical numerical mo-deling is important to ensure the safest and most operational mining sequence in the mine lifetime.

      Keywords: Bou Azzer East, cobalt, mining method, finite elements, geotechnical engineering


  1. Bitarafan, R., & Ataei, M. (2004). Mining method selection by multiple criteria decision making tools. The Journal of The South African Institute of Mining and Metallurgy, (10), 493-498.
  2. Boshkov, S.H., & Wright, F.D. (1973). Basic and parametric criteria in the selection, design and development of underground mining systems. SME Mining Engineering Handbook, (1), 12‑20.
  3. Hartman, H.L. (1987). Introductory mining engineering. New Jersey, United States: John Wiley & Sons, 592 p.
  4. Laubscher, D.H. (1981). Selection of mass underground mining methods. Design and Operation of Caving and Sublevel Stoping Mines, 23‑38.
  5. Morrison, R.G.K. (1976). A philosophy of ground control: A bridge between theory and practice. PhD Thesis. Montreal, Canada.
  6. Nicholas, D.E. (1981). Method selection – A numerical approach. Design and Operation of Caving and Sublevel Stoping Mines, 39-53.
  7. Alpay, S., & Yavuz, M. (2009). Underground mining method selection by decision making tools. Tunnelling and Underground Space Technology, 24(2), 173‑184.
  8. Alpay, S., & Yavuz, M. (2007). A decision support system for underground mining method selection. New Trends in Applied Artificial Intelligence, (4570), 334‑343.
  9. Azadeh, A., Osanloo, M., & Ataei, M. (2010). A new approach to mining method selection based on modifying the Nicholas technique. Applied Soft Computing, 10(4), 1040‑1061.
  10. Iphar, M., & Alpay, S. (2019). A mobile application based on multi-criteria decision-making methods for underground mining method selection. International Journal of Mining, Reclamation and Environment, 33(7), 480‑504.
  11. Javanshirgiv, M., & Safari, M. (2017). The selection of an underground mining method using the fuzzy TOPSIS method: A case study in the Kamar Mahdi II fluorine mine. Mining Science, (24), 161-181.
  12. Asadi Ooriad, F., Yari, M., Bagherpour, R., & Khoshouei, M. (2017). The development of a novel model for mining method selection in a fuzzy environment; case study: Tazareh coal mine, Semnan province, Iran. Rudarsko-Geološko-Naftni Zbornik, 33(1), 45-53.
  13. Abdellah, W.R.E., Hefni, M.A., & Ahmed, H.M. (2019). Factors influencing stope hanging wall stability and ore dilution in narrow-vein deposits: Part 1. Geotechnical and Geological Engineering, 38(2), 1451-1470.
  14. Ghazdali, O., Moustadraf, J., Tagma, T., Alabjah, B., & Amraoui, F. (2021). Study and evaluation of the stability of underground mining method used in shallow-dip vein deposits hosted in poor quality rock. Mining of Mineral Deposits, 15(3), 31-38.
  15. Kumar, H., Deb, D., & Chakravarty, D. (2017). Design of crown pillar thickness using finite element method and multivariate regression analysis. International Journal of Mining Science and Technology, 27(6), 955-964.
  16. Ozdogan, M.V., Yenice, H., Gönen, A., & Karakus, D. (2018). Optimal support spacing for steel sets: omerler underground coal mine in Western Turkey. International Journal of Geomechanics, 18(2), 05017003.
  17. Zhao, X., Li, H., Zhang, S., & Yang, X. (2019). Stability analyses and cable bolt support design for a deep large-span stope at the Hongtoushan mine, China. Sustainability, 11(21), 6134.
  18. RS2-11.0Z. (2021). Rock and Soil 2-Dimensional Analysis Program. Toronto, Canada: RocScience Inc.
  19. Jouravsky, G. (1952). Cobalt et nickel. Géologie des Gîtes Minéraux Marocains. Notes et Mémoires du Service Géologique, (87), 92.
  20. Maacha, L., Ennaciri, O., El Ghorfi, M., Saquaque, A., Alansari, A., & Soulaimani, A. (2012). 2.4-Le district à cobalt, nickel et arsenic de Bou Azzer (Anti-Atlas central). Les Mines De L’Anti-Atlas Central, (9), 91-97.
  21. Deere, D.U. (1964). Technical description of rock cores for engineering purpose. Rock Mechanics and Engineering Geology, 1(1), 17‑22.
  22. Barton, N., Lien, R., & Lunde, J. (1974). Engineering classification of rock masses for the design of tunnel support. Rock Mechanics, 6(4), 189‑236.
  23. Bieniawski, Z.T. (1989). Engineering rock mass classifications: A complete manual for engineers and geologists in mining. Civil, and petroleum engineering. New Jersey, United State: John Wiley & Sons.
  24. Hoek, E., Kaiser, P.K., & Bawden, W.F. (1995). Support of underground excavation in hard rock. London, United Kingdom: Balkema, 235 p.
  25. Marinos, P., & Hoek, E. (2001). Estimating the geotechnical properties of heterogeneous rock masses such as flysch. Bulletin of Engineering Geology and the Environment, 60(2), 85-92.
  26. Nicholas, D.E. (1992). Selection method. SME Mining Engineering Handbook, 2090‑2106.
  27. Gardner, E.D., & Vanderburg, W.O. (1933). Square-set system of mining. Washington, United States: U.S. Department of Commerce, Bureau of Mines.
  28. Bullock, R.L. (2011). Comparison of underground mining methods. SME Mining Engineering Handbook, 385‑403.
  29. Planeta, S., Szymanski, J., & Coulombe, A. (1988). Sequences optimales d’exploitation dans les gisements tres inclines. CIM Bulletin, 91(1025), 84‑90.
  30. Strength & Stress Analysis of Rock and Soil Materials. (2020). Rocscience Inc. Retrieved from:
  31. Hoek, E., & Brown, E.T. (1997). Practical estimates of rock mass strength. International Journal of Rock Mechanics and Mining Sciences, 34(8), 1165‑1186.
  32. Driouch, A., Ouadif, L., Lahmili, A., & Belmi, M.A. (2022). Evaluation of the compression potential of serpentine rock masses of the Bou Azzer Mining District in the Central Anti-Atlas of Morocco. Mining, Metallurgy & Exploration, 39(1), 189‑200.
  33. Лицензия Creative Commons