Study on appropriate support system and control criteria for main roadway under weak geological conditions in Indonesia

Takashi Sasaoka, Pongpanya Phnthoudeth, Akihiro Hamanaka, Hideki Shimada, Hiroshi Takamoto, Jiro Oya

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Indonesia is the second largest coal exporter to Japan, accounting for about 30 Mt annually. They produced over 400 Mt in 2015, over 99% of which is from open-cut mines. However, the conditions of surface mining are becoming worse year by year: the stripping ratio is increasing, the economy is worsening, and the infrastructure for coal transportation from inland mining areas is not being maintained. To meet the demand for coal in Indonesia and the rest of the world, underground mines have to be developed. In consideration of growing need, our research program is conducting a study on the potential for an underground coal mine in Indonesia. This research is being done through the roadway heading research program, which is looking into developing an underground coal mine from an open pit highwall. The greatest challenge for underground coal mine development in Indonesia is the maintaining the safety of the mine roadway during heading because the roof rock is exceptionally weaker. There is a potential for heading below mobile, unconsolidated soft sediment, and instead mining a deep area. This increases the likelihood for problems in the stability of the support system due to increasing ground pressure. The ground behavior around the roadway was measured using telltales, extensometers, and convergence measurements. Moreover, rock property tests were also conducted on exploration drilling cores. Based on the geological dates and monitoring data, a series of numerical analyses were conducted in order to assess support needs in the main roadway under different depths. Results of numerical analyses indicate that the current arch support design is effective when the mining depth is lower than 100m. However, if the mining depth is larger than 100m, the current arch support design should be changed to include the application of higher yield strength material, shorter spacing, etc. Moreover, bolting may also be useful if ground pressure is high locally. Based on a series of measurement data of ground and support behavior, a control criterion for main roadways under weak geological conditions is proposed in this paper.

Original languageEnglish
Title of host publicationProceedings of the 36th International Conference on Ground Control in Mining, ICGCM 2017
EditorsMichael Murphy, Brijes Mishra, Kyle Perry, Heather Lawson
PublisherSociety for Mining, Metallurgy and Exploration (SME)
Pages220-230
Number of pages11
ISBN (Electronic)9780873354561
Publication statusPublished - Jan 1 2017
Event36th International Conference on Ground Control in Mining, ICGCM 2017 - Morgantown, United States
Duration: Jul 25 2017Jul 27 2017

Publication series

NameProceedings of the 36th International Conference on Ground Control in Mining, ICGCM 2017

Conference

Conference36th International Conference on Ground Control in Mining, ICGCM 2017
CountryUnited States
CityMorgantown
Period7/25/177/27/17

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All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology

Cite this

Sasaoka, T., Phnthoudeth, P., Hamanaka, A., Shimada, H., Takamoto, H., & Oya, J. (2017). Study on appropriate support system and control criteria for main roadway under weak geological conditions in Indonesia. In M. Murphy, B. Mishra, K. Perry, & H. Lawson (Eds.), Proceedings of the 36th International Conference on Ground Control in Mining, ICGCM 2017 (pp. 220-230). (Proceedings of the 36th International Conference on Ground Control in Mining, ICGCM 2017). Society for Mining, Metallurgy and Exploration (SME).