ABSTRACT
In 2002, LKAB started to try an internationallyknown technique which can be called Stress Wave Superposition by using electronic detonators at Malmberget. The test results indicated that by using this method the vibrations had been reduced by 10%. But the reduction was not enough for Malmberget’s situation and the method required
regular single shot from production blasts, meaning the disturbance to mining production could be often, and the cost would be high. Accordingly, a new method was developed which is called Changing Initiation Sequence in Ring Blasts (CIS). The test results indicated that this method was efficient in vibration reduction. In addition, the third method, named Dividing Ring Blasting (DRB), was developed and then applied to some particularly-large rings with a success. All of the three methods have been reported by Zhang et al. (2004) and Zhang & Naarttijärvi (2005).
