Investigation of the effects of double primer explosive usage on velocity of detonation, grain size and fragmentation in open pit mine blasting operations

Drilling and blasting operations in mining are essential processes that directly impact the operational efficiency and costs in open-pit mining. This thesis study investigates the effects of double priming applications in drilling and blasting operations on particle size in two different open-pit mines. Experimental studies and analyses were conducted to evaluate the influence of double priming on the blasting process. The experiments were carried out with a total of 5 blasts in two different areas of the open-pit mines. In the first site blasts, measurements of in-hole detonation velocity (VOD) and particle size analysis were conducted for blasts performed with single priming and double priming. The results obtained indicate that blasts with double priming exhibit lower particle size, homogeneous fragmentation, and improved excavation-loading performance. In the second site blasts, emphasis was placed on optimizing the utilization of double priming through delay pattern and burden relief concepts. It was demonstrated that modifying the firing design to adjust the delay pattern and implementing proper burden relief can enhance excavation-loading performance by affecting particle size. The study revealed that the use of double priming increases detonation velocity, raises detonation pressure, reduces particle size, and improves excavation-loading efficiency. Furthermore, the impact of delay sequencing on particle size and the improvement of excavation-loading performance through proper delay sequencing and burden relief were demonstrated. Specifically, for long holes, the use of double priming and optimization of delay sequencing were identified as significant parameters for achieving efficient blasting results.