Abstract: The large lump rate of aggregate mine bench blasting is an important indicator for evaluating the effectiveness of mining blasting. Taking a tuff aggregate mine as an example,firstly,a blasting block size and rock dynamic damage correlation model was established based on field block size distribution and numerical simulation analysis. Secondly,based on this correlation model,numerical simulations of bench blasting in cracked rock mass were carried out with inter-hole delay times of 9 ms,11 ms,13 ms,15 ms,17 ms,and 20 ms respectively,with the main purpose of reducing the large lump rate and taking into account the control of powder ore rate to obtain the best inter-hole delay. Finally,field blasting tests were conducted with the optimized inter-hole delay obtained by the simulation calculation. The results show that there is an exponential function relationship between the blasting block size and the damage value from numerical simulation. In the above delay time,with interhole delay time decreases,the large lump rate gradually decreases and the powder rate gradually increases. When the inter-hole delay time is 15 ms,the blasting effect is the best. The results of mine field application show that when the inter-hole delay time is adjusted to 15 ms,the blasting large lump rate is reduced by 13. 73 percentage points,the powder ore rate increases by 0. 73 percentage points,and the average crushing size is reduced correspondingly. 

Key words: aggregate mine,large lump rate,inter-hole delay time,rock damage,numerical simulation