Parametric stability analysis of pillar performance at Nohyun limestone mine, South Korea—a case study

  • Jong-Gwan Kim
  • Wael R. AbdellahEmail author
  • Hyung-Sik Yang
Original Paper


The objective of this paper is to evaluate the performance of pillars located on level #3 at Nohyun limestone mine that uses the room-and-pillar method. The mine is located at South of Cheongju city, North Chungcheong Province, South Korea. A series of two-dimensional elasto-plastic finite-difference models has been constructed using FLAC2D software. Factor of safety (FOS) is then calculated using fish-code (“solve FOS”), an internal command of FLAC built on a shear strength reduction technique. The results are presented and discussed in terms of stress state, deformation, and factor of safety with respect to mining sequence, mining depth, and mineshaft width. The results reveal that the stability of pillars deteriorates when level #3 is entirely mined out after extracting level #2 (i.e., FOS = 1.33 to 1.55). In addition, the safety of pillars is sharply dropped (i.e., FOS = 1.16 to 1.33) when mining depth extends to 15 m; and similarly, width of mineshaft increases by 2 m. Also, a comparison of calculation of safety factor, FOS, employing numerical modelling (i.e., FOS = 1.16 to 1.86), and analytical methods (i.e., FOS = 7.35 to 36.36) has revealed that numerical modelling is more conservative from a design point of view. The study also indicates that the overall mine stability is influenced by the discordance in the pillar arrangement between adjacent levels. Therefore, it is recommended that the pillar design should be dictated by the inclination of the orebody.


Room-and-pillar method Parametric stability analysis Factor of safety (FOS) Nohyun limestone mine 


  1. Bieniawski ZT (1967) Discussion- a study of the strength of coal pillars by M.D.G. Salamon and A. H. Munro. And a method of designing bord and pillar workings by M. D. G. Salamon. J South Afr Inst Min Metall 68(2):185–199Google Scholar
  2. Bunting D (1991) Chamber pillars in deep anthracite mines. Trans AIME 42:236–245Google Scholar
  3. Chikande T, Zvarivadza T (2016) Review of support systems used in poor ground conditions in platinum room and pillar mining: a Zimbabwean case study. J South Afr Inst Min Metall 116:323–332CrossRefGoogle Scholar
  4. Choi SO, Kim BR, Son H (2017) Analysis of safety pillar stability considering weathering characteristics of rock in underground limestone mine. 4th ISRM Young Scholars Symposium on Rock Mechanics, Jeju, Korea, pp 10–13Google Scholar
  5. Choochang S-N (2013) Room and pillars design for Phetchaboon coal mine project. M. Eng. Thesis, Suranaree University of Technology, Nakhon Ratchasima, ThailandGoogle Scholar
  6. Clarke BG Welford M, Hughes DB (2006) The threat of abandoned mines on the stability of urban areas. IAEG2006, Nottingham, United Kingdom, 6-10 September 2006. Available online: Accessed 18 Nov 2016
  7. Dehghan S, Shahriar K, Maarefvand P, Goshtasbi K (2013) 3-D numerical modelling of Domino failure of hard rock pillars in Fetr6 Chromite Mine, Iran, and comparison with empirical methods. J Cent South Univ 20:541–549CrossRefGoogle Scholar
  8. Esterhuizen GS (2007 Jan) Evaluation of the strength of slender pillars. Trans Soc Min Metall Explor 320:69–76Google Scholar
  9. Esterhuizen GS, Iannacchione AT, Ellenberger JL, Dolinar DR (2006) Pillar stability issues based on a survey of pillar performance in underground limestone mines. 25th International Conference on Ground Control in Mining, Morgantown, WV, pp 354–361Google Scholar
  10. Esterhuizen GS, Dolinar DR, Ellenberger JL, Prosser LJ, Iannacchione AT (2007) Roof stability issues in underground limestone mines in the United States. Proceedings of the 26th International Conference on Ground Control in Mining, Morgantown, WV, pp 320–327Google Scholar
  11. Esterhuizen GS, Dolinar DR, Ellenberger JL (2008) Pillar strength and design methodology for stone mines. In: Peng SS, Tadolini SC, Mark C, Finfinger GL, Heasley KA, Khair AW, Luo Y, eds. Proceedings of the 27th international conference on ground control in mining. Morgantown WV: West Virginia University. p. 241–253.Google Scholar
  12. Fahimifar A, Oreste P, Ranjbarnia M (2013) The dimensioning of pillars in the mining rooms and pillars method through a detailed evaluation of the stress conditions in the rock. Adv Environ Geol Sci Eng, pp.68-77. Available at
  13. Gaede O, Schrank C, Canbulat I, Karrech A (2014) A strain-based failure criterion for pillar stability analysis. AUSROCK 2014: Third Australasian ground control in mining conference, Sydney, NSW, pp 5–6Google Scholar
  14. Guy R, Kent M, Russell F (2017) An assessment of coal pillar system stability criteria based on a mechanistic evaluation of the interaction between coal pillars and the overburden. Int J Min Sci Technol 27:9–15CrossRefGoogle Scholar
  15. Hedley DGF, Grant F (1972) Stope-and-pillar design for the Elliot Lake Uranium Mines. Bull Can Inst Min Metall 65:37244Google Scholar
  16. Hosseini N, Oraee-Mirzamani B, Oraee K (2012) The Evaluation of Empirical Coal Pillar Strength Formula Based on Uncertainty Criterion. In Proceedings of the Thirty First International Conference on Ground Control in Mining, West VirginiaGoogle Scholar
  17. Idris M, Saiang D, Nordlund E (2015) Stochastic assessment of pillar stability at Laisvall mine using Artificial Neural Network. Tunn Undergr Space Technol 49:307–319CrossRefGoogle Scholar
  18. Jessu KV, Spearing A, Shafiezadeh M (2018) Laboratory and numerical investigation on strength performance of inclined pillars. Energies 11(11):3229. CrossRefGoogle Scholar
  19. Kendorski, F.S., (2007), , Proceedings, 26th International Conference Ground Control in Mining, Morgantown, WV, pp 298-303.Google Scholar
  20. Kimmelmann MR, Hyde B, Madgwick RJ (1984) The use of computer applications at BCL Limited in planning pillar extraction and design of mining layouts. In: Brown ET, Hudson JA (eds) Proceedings of ISRM Symposium: Design and Performance of Underground Excavations. British Geotechnical Society, London, p 53263Google Scholar
  21. Kortnik J (2015) Stability assessment of the high safety pillars in Slovenian natural stone mines. Arch Min Sci 60(1):403–417Google Scholar
  22. Krauland N, Soder PE (1987) Determining pillar strength from pillar failure observations. Eng Min J 8:34240Google Scholar
  23. Mete Kun, Baran Tufan, Nejat Kun (2014) The applicability of underground mining methods in limestone quarries of Western Taurus. Proceedings of the International Conference on Mining, Material and Metallurgical Engineering Prague, Czech Republic, Paper No. 61. Paper can be found at
  24. Li C, Xu J, Wang Z, Qin S (2013) Domino instability effect of surrounding rock-coal pillars in a room-and-pillar gob. Int J Min Sci Technol 23:913–918CrossRefGoogle Scholar
  25. Lunder PJ (1994) Hard rock pillar strength estimation and applied empirical approach. M. Sc. thesis of applied sciences. Department of Mining and Mineral Process Engineering, University of British Columbia, Vancouver, CanadaGoogle Scholar
  26. Lunder PJ, Pakalnis R (1997) Determining the strength of hard rock mine pillars. Bull Can Inst Min Metall 90:51–55Google Scholar
  27. Luo Y (2015) Room-and-pillar panel design method to avoid surface subsidence. Min Eng 67:105–110Google Scholar
  28. Ma H, Wang J, Wang Y (2012) Study on mechanics and domino effect of large-scale goaf cave-in. Saf Sci 4:689–694CrossRefGoogle Scholar
  29. Martin CD, Maybee WG (2000) The strength of hard-rock pillars. Int J Rock Mech Min Sci 37:1239–1246CrossRefGoogle Scholar
  30. Mathey M, Van der Merwe JN (2016) Critique of the South African squat coal pillar strength formula. J South Afr Inst Min Metall 116:291–299CrossRefGoogle Scholar
  31. Obert L, Duval W (1967) Rock Mechanics and the Design of Structure in Rock, vol 650. Wiley, New York, NYGoogle Scholar
  32. Peng SS (2007) Ground control failures: a pictorial view of case studies. West Virginia University Press, Morgantown, WV, USAGoogle Scholar
  33. Potvin Y, Hudyma MR, Miller HDS (1989) Design guidelines for open stope support. Bull Can Min Metall 82:53262Google Scholar
  34. Poulsen BA, Shen B (2013) Subsidence risk assessment of decommissioned bord-and-pillar collieries. Int J Rock Mech Min 60:312–320CrossRefGoogle Scholar
  35. Sahu P, Lokhande RD (2015) An investigation of sinkhole subsidence and its preventive measures in underground coal mining. Procedia Earth Planet Sci 11:63–75CrossRefGoogle Scholar
  36. Salamon MDG, Munro AH (1967) A study of the strength of coal pillars. J South Afr Inst Min Metall 68:55–67Google Scholar
  37. Shao XP, Shi PW, Wang HX (2009) Study on pillars stability by keeping water in strip mining for small and medium-sized mines in northern Shanxi Province. Coal Technol 28:58–61 In ChineseGoogle Scholar
  38. Sjöberg J (1992) Failure modes and pillar behaviour in the Zinkgruvan mine. In: Tillerson JA, Wawersik WR (eds) Proceedings of 33rd U.S. Rock Mechanics Symposium, Sante Fe. A.A. Balkema, Rotterdam, p 4912500Google Scholar
  39. Tzalamarias M, Tzalamarias I, Benardos A, Marinos V (2018) Room and pillar design and construction for underground coal mining in Greece. Geotech Geol Eng 37:1–14. CrossRefGoogle Scholar
  40. Ünlü T (2001) Critical dimension concept in pillar stability. In: Proceedings of th 17th International Mining Congress and Exhibition of Turkey, pp 341–347. Paper can be accessed at
  41. Yang HS, Kim WB, Ali MA (2012) Performance of pillar design in underground stone mines that include discontinuities. Geosystem Engineering, 15:3 187-194, CrossRefGoogle Scholar
  42. Yu Y, Chen S, Deng K, Fan H (2017) Long-term stability evaluation and pillar design criterion for room-and-pillar mines. Energies 10:1644. CrossRefGoogle Scholar

Copyright information

© Saudi Society for Geosciences 2019

Authors and Affiliations

  • Jong-Gwan Kim
    • 1
  • Wael R. Abdellah
    • 2
    Email author
  • Hyung-Sik Yang
    • 3
  1. 1.Technology Planning Team/Technology Management DivisionKorea Resources CorporationWonjuSouth Korea
  2. 2.Mining and Metallurgical Engineering Dept., Faculty of EngineeringUniversity of AssiutAssiutEgypt
  3. 3.Department of Energy & Resources EngineeringChonnam National UniversityGwangjuSouth Korea

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