Large scale panel destress blasting parametric study
Résumé
The purpose of this parametric study is to quantify the effect of panel destressing on a steeply dipping remnant ore pillar. A large-scale destress blast program is simulated in the hanging wall of the ore pillar using the finite difference program FLAC3D. The simplified model consists of a 10MT ore pillar divided into 20 stopes on two levels. Two panels are destressed in the hanging wall to cover 8 stopes, followed by the mining of 4 stopes in the stress shadow in a retreat sequence. The varied parameters are the rock fragmentation factor (α) and stress reduction factor (β) of the destress panel. The effect of panel destressing is evaluated based on the volume of ore at risk in the stress shadow as well as the sudden stress change in the stope caused by the destress blast. Overall, a successful blast with a realistic stress reduction factor and rock fragmentation factor reduces the major principal stress in the nearest stopes by 10MPa to 25MPa. This yields a reduction of ore at risk volume ranging from 8% to 50% in the stress shadow as the first 4 stopes are mined.
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