Excavation of high-stressed hard rock with roadheader

Drill and blast method becomes unfavorable for deep mining of hard rock. Mechanical excavation with roadheader EBZ160TY was trialed at work face with hard rock and high ground stress. Work procedure and performance of the roadheader were recorded and analyzed. The results showed that, roadheader EBZ160TY, with designed excavating strength of 80 MPa, presented amazingly good performance in hard rock with strength of 148 MPa and consumed less cost compared to drill and blast method. High stress was found to play positive role in improving its working ability. Under the gentle disturbance of roadheader excavation, the high ground stress brings the surrounding rock mass to deform into yield and lets the stress/strain energy transform into fracture energy of rock fragmentation. With the push and rotation of roadheader, structural instability of confined high-stressed particle aggregate other than rock failure by mechanical wearing happens. The results show a good application prospect for roadheader in hard rock excavation especially at deep level.