Profile
Material: Coal
Hole Condition: 100% Wet
Digging Time: ≤ 12 seconds
Explosive: ANFO
Optimization Method: Water
Decking BLASTBAG™
Krakatau
Challenge
Uncontrolled Blasting Energy in Wet Holes
At one of our client's operations, the blasting process was conducted in 100% wet conditions in several locations, with water filling the entire depth of the drill hole. This situation often resulted in decreased blasting performance because the explosive energy was not optimally channeled.
Furnishing blast holes filled with water presented a series of technical risks for our client, including:
- Uncontrolled energy → water absorbs and diverts blast energy.
- Flyrock increases → without energy control, rock ejection is further and riskier.
- Fumes appear → incomplete combustion in wet holes.
- Productivity decreases → poor fragmentation increases digging time.
Solution
MTi Blastbag™ Application for Energy Confinement in Wet Holes
To address these issues, our client implemented Blastbag™ Krakatau in holes with 100% wet conditions. Blastbag™ Krakatau is designed to:
- Improve blast energy confinement, resulting in more targeted and stable energy distribution.
- Create a natural air deck to reduce initial blast pressure without sacrificing energy control.
- Protect the explosive column from water, resulting in optimal detonation.
- Minimize the risk of flyrock and fumes caused by water pressure and incomplete combustion.
With an inflation rate of only ±20 seconds, Blastbag™ Krakatau can be easily installed even in holes already filled with water. Once inflated, the product locks firmly to the hole wall, providing stable support for the explosive column during loading and firing. The Blastbag provides stability to the explosive column even in completely wet hole conditions.
Results
Real-World Evidence of Blastbag Effectiveness in Wet Hole Conditions
- Flyrock
Table 1 shows that the blasting results demonstrate that the application of the Krakatau Blastbag™ provided control of blast energy.-
- The shorter flyrock distance (46 m) indicates better containment of blast energy, resulting in more targeted energy distribution and a reduced equipment safety radius.
- The absence of fumes indicates more complete combustion of the explosives because the column was not contaminated by water.
Without the Blastbag™, the flyrock reached 93.6 m, indicating less controlled blast energy. The presence of fumes in the scenario without the Blastbag™ indicates incomplete detonation due to the interaction of the explosives with water.
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- Digging Time
Digging time measurements were conducted to assess the quality of blast fragmentation, reflecting how effectively the blast energy worked in breaking the rock.- Digging time with the Krakatau Blastbag™ was 8.5 seconds, 29% faster than the 11.1 seconds without the Blastbag™.
- Improving fragmentation quality reduces fuel consumption and shortens cycle times, resulting in operational cost savings and increased daily productivity.
Conclusion
The implementation of Blastbag™ Krakatau in 100% wet hole blasting at our client's site resulted in significant improvements in safety, energy performance, and equipment productivity.
- Flyrock was reduced by 50% (46 m vs. 93.6 m).
- No fumes were generated.
- Digging time was 3.6 seconds faster than blasting without Blastbag™ Krakatau.
- Finer fragmentation supported dig-loading efficiency in the final layer.
Overall, Blastbag™ Krakatau proved to be an effective solution for ensuring energy control, operational safety, and optimal productivity in our client's 100% wet hole blasting.
