Evaluation of Optimum Burden for the Excavation of Narrow Vein Ore Deposits Using Numerical Simulation

Burden is one of the major influencing blast design parameters which should be optimised for the extraction of narrow vein ore bodies. Numerical simulation-based approach has been used for the optimisation of burden in this paper. Different models were prepared under varying parametric conditions including width of the vein, blasthole diameter and burden. The RHT concrete constitutive model was used for the analysis of damage contour. The volume of the excavated rock along the free face (EV) was quantified from the model output in all the scenario. The study showed that EV initially increases with the increase in burden for a particular width of vein. Furthermore, EV starts decreasing after a point termed as pivot point. The value of burden at this pivot point was considered as optimal in this study. The best fit curve between EV and burden for three blasthole diameter and seven different width of vein were plotted. In all instances, the outputs of the model followed the second-degree polynomial equation. The study also suggests that the optimum burden reduces with the increase in the width of the vein. It has also been found that the optimum burden follows power trend with the increase in width of the ore body irrespective of blasthole diameter. Based on the optimum burden obtained from the output of simulation along with different blasthole diameter and width of the ore body, an empirical relationship has been established. The developed empirical relationship has a good agreement with the experimental trial data.