Numerical Study on Roadway Stability under Weak Geological Condition of PT Gerbang Daya Mandiri Underground Coal Mine in Indonesia

Phanthoudeth Pongpanya, T Sasaoka, H. Shimada, B. Ulaankhuu, J. Oya, S. Dwiki, T. Karian


This paper aims to assess the roadway stability of the PT Gerbang Daya Mandiri (GDM) underground coal mine. A numerical analysis method using 3D finite difference code (FLAC 3D) was used to investigate the failure zone behavior of the roadway at various overburden depths (50 m, 100 m, 200 m, and 300 m). The outcome of this research was the most appropriate support system of the roadway. The results of numerical analyses indicated that the excavation depth affected the thickness of failure zone, and the capacity of the support system was significantly associated with an increase of the overburden depth. Steel set, cablebolt, and rockbolt supports were assessed in this paper. The steel set is selected as the main support system in GDM coal mine, and it is effective to stabilize the roof and sidewalls of the roadway until 200 m depth. As the failure zone becomes larger at the deeper sites, the cablebolt support is introduced to control the floor stability, and the use of rockbolt in combination with steel set is suggested to support the roof and sidewalls.


roadway stability; weak geological condition; support system; numerical analysis; FLAC3D

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Indonesia-Investments, “Coal in Indonesia,”

T. Sasaoka, H. Takamoto, H. Shimada, J. Oya, A. Hamanaka, and K. Matsui, “Surface subsidence due to underground mining operation under weak geological condition in Indonesia,” International Journal of Rock Mechanics and Geotechnical Engineering, vol. 7, 2015, pp. 337-344.

H. Takamoto, T. Sasaoka, H. Shimada, J. Oya, A. Hamanaka, and K. Matsui, “Study on surface subsidence due to longwall mining operation under weak geological condition in Indonesia,” ICGCM China Proceedings, 2014.

T. Sasaoka, H. Shimada, N. Zarlin, H. Takamoto, K. Matsui, S. Kramadibrata, and B. Sulistianto, “Geotechnical issues in the application of rock bolting technology for the development of underground coal mines in Indonesia,” International Journal of Mining, Reclamation and Environment, vol. 28, 2014, pp. 150-172.

K. Matsui, H. Shimada, H.Furukawa, S. Kramadibrata, and H.Z. Anwar, “Ground control problems and roadheader drivage at Ombilin coal mine, Indonesia,” Proceeding of the 18th International Mining Congress and Exhibition of Turkey-IMCET, 2003.

T. Sasaoka, H. Shimada, M. Ichinose, K. Matsui, S. Kramadibrata, B. Sulistianto, and R. Watinena, “Improvement in roof support system at a new underground coal mine developed from open-cut highwall in Indonesia,” Proceeding of the 26th International Conference on Ground Control in Mining, 2007.

T. Sasaoka, H. Shimada, A. Hamanaka, B. Sulistianto, M. Ichinose, and K. Matsui, “Geotechnical issues on application of highwall mining system in Indonesia,” Vietrock 2015 an ISRM Specialed Conference, 2015.

A. Garcia, P. Altounyan, A. Nitaramorn, and A. Lewis, “Ground control aspects of a successful underground coal mine trial in weak strata in Indonesia,” Proceeding of the 29th International Conference on Ground Control in Mining, 2010.

Z. T. Bieniawski, “Estimating the strength of rock materials,” International Journal of the South African Institute of Mining and Metallurgy, vol. 74, 1974, pp. 312-320.

Itasca Consulting Group, Inc., “FLAC3D version 5.01,” Mill Place, An Itasca International Company.

E. Hoek, and E. T. Brown, “Underground excavations in rock,” Institution of Mining and Metallurgy, London, UK, 1980.

E. Hoek, P. K. Kaiser, and W. F. Bawden, “Support of underground excavations in hard rock,” West Broadway Professional Centre, Vancouver, British Columbia, 1993.

E. Hoek, “Practice Rock Engineering,” Evert Hoek Consulting Engineer Inc., North Vancouver, B.C., Canada V7R 4X1, 2006.

N.E. Yasitli, and B. Unver, “3D numerical modeling of longwall mining with top coal caving,” International Journal of Rock Mechanics and Mining Sciences, vol. 42, 2005, pp. 219-235.

E. Hoek, “Tunnel support in weak rock,” Symposium of Sedimentary Rock Engineering, 1998.


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