ABSTRACT
The Homestake Gold Mine, USA, tried to excavate a raise by one-shot blasting with spherical charges but failed. A reappraisal was carried out and a survey of the raise with a 3D laser scanner discovered the cause of the failure. A square blast hole pattern, short-delay between different layers, and constant layer height used could not make a successful excavation. In light of this problem, the main objective of this study is to reduce the fracture of the rock. A number of different blasting techniques such as a circular blast hole pattern, presplitting, deck charging, and different sequences was tested. The LS-DYNA software and a crater test were employed to verify the method using the above techniques. This method was named one-shot-deep-hole driving by using multi-spherical charges. This method has been used to excavate with a success.
