Advanced Blasting Technology for Large Scale Distress Blasts at Brunswick #12 Mine

CIM Montreal 2003
Blaine Ellis, Stephen Chung,
Abstract Mining in highly stressed ground conditions has been an increasing challenge at the Brunswick Mine. Due to historical reasons, there were 2 large regional pillars left behind on the 1000 m Level to support the ground for safe extraction of the ore around: the South Regional Pillar with about 5 million tonnes of ore and the North Regional Pillar with about 3 million tonnes of ore. In the fall of 2000, a series of ground movement events occurred in the South Regional Pillar along weak geological structures around the south-west corner of the pillar. As a result, mining activities in the regional pillar was suspended. After extensive geotechnical investigations, a decision was made to carry out a mass destress blast in the West Ore Zone (WOZ) to cut the principal stress across an area of 135 m along the strike and 86 m high. At the end of July 2001, the WOZ mass blast was successfully initiated. It was with this success that the mine decided to take the similar approach to destress the North Regional Pillar (NRP) which is scheduled to blast in early year 2003. Advanced blasting technologies played an important role in achieving the successful blasts. First of all, the state-of-the-art electronic detonators were applied in the initiation system. The high precision of delay timing and long delay duration of the electronic detonators ensured accurate and reliable initiations of over 800 blastholes in the WOZ mass blast. Secondly, Orica’s DMC_Blast simulation code was used to study different blasting blocks for the desired timing in the initiation sequence. This paper describes the process of applying electronic detonators in complex blasts, as well as how blast simulation results are interpreted to guide engineering design of the mass blasts.

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