Best practices for pre-split blasting in Hard Rock

[muddybootminer]

Is anyone on here experienced with pre-split blasting in hard rock? I'm interested in comparing techniques that ensure good wall control and reduce overbreak. What spacing, types of charges, or timing methods have you found to be most effective in practice?

 

[rockdrillpro]

For clean walls and less overbreak, pre-split blasting needs tight spacing, decoupled charges, and exact timing. Smaller holes and steady burden are what you want.

 

[dust&diesel]

Also, try using drilling rigs that are very precise. These rigs should have consistent hole depth. Getting the stemming right helps keep the energy in place and makes for better splits

 

[4pplepen]

Is anyone on here experienced with pre-split blasting in hard rock? I'm interested in comparing techniques that ensure good wall control and reduce overbreak. What spacing, types of charges, or timing methods have you found to be most effective in practice?

just wanna say that for timing, you need the pre split line to go simultaneously or use the absolute shortest deck delays possible. The whole idea is to get that fracture line established before your main production blast even thinks about firing.
If you see underbreak (the wall not breaking back to your line), you probably need to tighten the burden between your presplit and the first row of production holes

 

[Alan]

Appreciate you breaking that down so clearly. That’s some really valuable advice for anyone dealing with blast timing.