Geotechnical issues in the application of rock bolting technology for the development of underground coal mines in Indonesia

TLDR

Rock bolting has been attempted in Indonesian underground coal mines for years without success. The paper investigates the feasibility of rock bolting in weak‑strata underground coal mines in East Kalimantan and discusses its applicability. A comprehensive monitoring system was installed to track ground behavior and characteristics during the trials. One trial ended in a fatal roof fall, while the other showed that bolted roadways remained reasonably stable despite roof falls, and the monitoring system enabled timely support adjustments.

Abstract

The application of a rock bolting system for Indonesian underground coal mines has been attempted for several years without any success. Recently, two new underground mining trials were conducted in East Kalimantan, Indonesia, in order to investigate the possibility of using rock bolting to address the technical challenges of underground coal mines under weak geological conditions. Unfortunately, one of the trials failed and was given up due to a fatal roof fall accident. However, in another trial, even though roof falls have occurred within the working area, the bolted roadways showed reasonable stability over time. Moreover, a comprehensive monitoring system has been installed in order to monitor the ground behaviour and its characteristics. This application of a comprehensive monitoring system has enhanced the ability to increase the level of support and to react to changing/deteriorating conditions. This paper describes the conditions and geotechnical issues for underground mines in Indonesia, and discusses the applicability of the rock bolting system to address problems associated with weak strata conditions in Indonesia.