Simulating blasting parameters for sharp inclined thin vein mines

Abstract

Exploiting a sharply-dipping thin vein mine is a challenging task because of the troubles in ore drawing and functioning large-scale mining tools in the limited underground space. Thus, considerations are mandatory to assume an effective mining technique that is able to handle unequal boundaries of this kind of orebody, providing a high recovery rate while lessening preparations before/after stoping and ore dilution. This paper analyses the medium-deep hole blasting of sharply inclined thin vein mines under different blasting factors using LS-DYNA. The links between blasting factors and over-under-excavation percentage of blasting, blasting cracks' density and nearby rock particles' vibration velocity are proven in the current research. Results show that segmental blasting is not much different from one-time blasting in the whole center section in terms of the blasting effect, but its impact on nearby rock is smaller. Two types of holes were designed in W- and X-type, and the distance between the holes were selected to be 0.8, 0.9, 1 m, with total 6 hole types. The effective stresses and displacements at the key monitoring points of the modeled nearby rock were analyzed by W- and X-types of hole placement. Compared with X-type holes, the effective stresses and displacements of W-type holes are smaller, indicating that W-type holes cause less damage to nearby rock. Based on the cumulative damage cloud map, it was concluded that the 0.8 m hole spacing had a larger influence on nearby rock, and that 0.9 m hole spacing was selected considering the factors of blasting effectiveness and resource recovery efficiency. Finally, this mining technique has the potential to be broadly employed to exploit related orebodies.