Abstract:
Aiming at the problem of high boulder yield under different thicknesses of frozen soil in high latitude
and alpine region,blasting crater tests were carried out at low temperatures in winter in Unugtushan copper-molybdenum mine. According to the test results,the relationship between the charge parameters and the blasting crater parameters is determined by using the Livingston blasting crater theory. Simultaneously,the deformation energy coefficient of the frozen soil layer is calculated,and the blasting crater characteristic curves of different frozen soil thicknesses are analyzed. When the charging amount is 4 kg,the critical depth of the frozen soil is 1. 3 m,the optimal
depth is 0. 84 m,and the deformation energy coefficient is 1. 06. When the charging amount is 8kg,the critical depth
of the frozen soil is 1. 7 m,the optimal depth is 1. 2 m,and the deformation energy coefficient is 1. 05. When the
charging amount is 12kg,the above parameters are 2. 2 m,1. 34 m and 0. 95,respectively. According to the similarity
law,the optimal charging parameters which are suitable for the frozen soil area on the site are derived,the blasting
effect under multiple blasting parameters of different frozen soil thicknesses is compared and analyzed. In addition,
the blasting effect is optimized by the principle of“sub-regions and stages”. For weak frozen soil,the blasting effect
can be improved with shorter stemming length and longer charge length. For strong frozen soil area,auxiliary holes are
added around the main blasting holes to reduce the boulder yield. Furthermore,the optimization scheme of blasting
parameters which is suitable for the change of frozen soil layer thickness in Alpine region is summarized. As a result,
the blasting effect is significantly improved,which greatly reduces the boulder yield after blasting of the frozen soil
layer and improves the ore supply rate.
Key words:
alpine region; frozen soil blasting; blasting effect; parameter optimization; blasting crater