Preparation of the Blast Site
- Mark and Drill Holes: Begin by marking and drilling blast holes to the specified depth, according to the blast design plan. The layout and spacing of the holes should align with the desired fragmentation size.
- Clear the Blast Area: Ensure all non-essential personnel are at a safe distance from the blast site before handling explosives.
Choose the Explosive Type
- Match the type of explosive (e.g., ANFO, emulsion, e.t.c) to the rock type, hole size, and site conditions. Lower-energy explosives work for soft rocks, while higher-energy explosives are necessary for hard rock.
- Initiation Systems: Select appropriate initiation systems such as detonators (electric, non-electric, or electronic) and primers, based on delay timing and blast sequence requirements.
Charging the Explosive
- Priming: Insert primers and detonators first, ensuring they are placed securely in the hole and connected properly. Priming assists with initiating the main explosive charge.
- Loading Explosives: Carefully load the explosive material into the hole to the required height or weight. Avoid using metal tools to prevent sparks; use non-metallic tamping rods if needed.
- Stemming: Seal the top of each hole with stemming material (e.g., crushed stone or gravel). Stemming keeps the explosive force confined within the borehole, increasing blasting efficiency and minimizing fly rock.
Connecting the Blast Circuit
- Wiring Sequence: Connect the blast holes in a planned sequence to control the detonation timing. For complex blasts, use delays or electronic detonators for precision.
- Inspect Connections: Double-check all connections for continuity and proper placement.
Final Inspection
- Safety Check: Conduct a final inspection of the blast layout and all connections. Ensure all personnel are in a safe location before detonation.
- Alert Area and Detonate: Sound a warning to clear personnel from the area, confirm the blast site is clear, and proceed with the controlled detonation as per site protocol.
Safety Guide on Explosive Handling
Only licensed and trained personnel should handle, charge, or detonate explosives. Conduct regular safety drills, training on explosive handling, and emergency response. In Case of Misfire,learly mark misfired holes and communicate the situation to all personnel.
Delay Re-entry: Only attempt to re-enter the blast area after a sufficient wait period, per industry standards (typically 30 minutes to several hours).
Disposal by Experts: Engage experienced personnel or the explosives manufacturer for safe disposal or neutralization of the misfired charge.
Post-Blast Inspection
Check for Hazards: Inspect for any unexploded charges, fly rock, or residual explosive material after each blast.
