Geotechnical Risk Assessment and Selection of Suitable Roadheaders for Tabas Coal Mine Project, Iran

Geotechnical risks play an important role in the selection of tunneling method and machine types. In order to prevent some geological and geotechnical hazards during tunneling, selecting the most appropriate tunneling machine is very important. In this research study the main geotechnical hazards of tunneling by roadheader with their common mitigation measures are discussed. At present, three roadheader are excavating the three drifts of the Tabas coal mine in Iran. Hence, these drifts were used in this research study. The risk assessment matrix method in these tunnels showed that there is a lower risk of tunneling by roadheader than utilising the drilling and blasting method. The determined geotechnical risk assessment showed that the transverse cutter head was more suitable in comparison to a longitudinal cutter head for such tunnels. Then by using an instantaneous cutting rate model, the cutter head power of the roadheader was determined. According to the model, a lightweight roadheader with a cutter head power of about 80-110 KW and 40 t weight are suitable. Finally, four types of manufactured roadheader with similar specifications were selected.