Optimization Charge Scheme for Multi-row Ring Blasting Design Adopting Equilateral Triangle Layout Based on Modified Harries’ Mathematical Model from a Fragmentation Perspective: A Case Study

To eliminate undesired phenomena such as brow damage and excessive fines owing to the energy concentration on the collar of the ring, a fragment simulation using a charge scheme optimization algorithm is proposed based on modified Harries model in this article. First, the traversal algorithm for an arrangement of regular holes (holes charged to the collar) is proposed based on the analysis of the current interval charge design method in ring blasting. Second, a new developed mathematical model based on Harries model is introduced to predict the fragment size of the column charge using the superposition method. Then, the optimization criteria based on the calculated blasted fragment matrix are discussed. Finally, a case study is introduced to illustrate the usage and optimization procedure of the program. Ten trial blastings were conducted in the Tonglvshan copper mine to verify the feasibility and effectiveness of the optimization algorithm. The findings reveal that the probability of brow damage was reduced efficiently.