Removal of a silo blockage by “intelligent blasting” as a special operation with electric ignition
When blasting work is reported, many readers think of collapsing bridges or residential buildings that are razed to the ground in a matter of seconds. When it comes to solving a material blockage in a storage silo, few people would think of the use of explosives. A silo is an enclosed space and the assumption is that a blast inside the silo will result in an explosion or damage to the entire facility. However, it is actually possible to remove a material blockage through targeted blasting. How does this work?
Our experts at NT Service GmbH have the know-how and the technical capabilities to carry out “intelligent blasting” successfully and without damaging the silo or the environment. Read how this is possible and follow the pictures to the text.
What was our mission?
A company in the filter dust disposal sector reported massive silo compaction and blockages in their plant. We were commissioned to break up the blockage and remove the silo compaction. Our task was to break up the heavily clumped material so that it could then be extracted. It goes without saying that there must be no increased pressure in the silo during the work, nor should there be any damage to the silo walls.
How did our experts prepare for the mission?
The basis for the use of explosives is a comprehensive risk assessment. This is carried out by the team leader from NT Service and the blasting expert from our cooperation partner Sprengtechnik Berge. The company has more than 40 years of expertise in the field of borehole blasting. The risk assessment is carried out in accordance with the requirements of the DGUV regulations. It includes regulations and information such as the application instructions Spreng TR 310 (more on this in the next paragraph).
As is essential for every operation, a safety concept is drawn up in the second step and then documented by the team leader. The concept includes:
- Inspection of the silo facility using rope access technology
- Safe maneuvering within the silo system by access technicians
- Properly drilled holes for the explosive charges at the correct distance from each other
- Timely and orderly exit from the silo facility
- Safety and rescue measures for all conceivable incidents during the operation
The actual work can only begin once the comprehensive safety concept has been drawn up, discussed and documented.
What is regulated by the DGUV information on the application of Spreng TR 310?
The German Social Accident Insurance (DGUV) provides assistance for authorized blasters and companies in the implementation of blasting work in the form of the application instructions for blasting TR 310. The most important aim is to prevent accidents at work and work-related health hazards, and application and practical examples are also explained in detail. Furthermore, the application notes serve to ensure that the technical regulations of the law on explosives are properly complied with. You can find detailed information on the application instructions for the DGUV’s Spreng TR 310 here: https://publikationen.dguv.de/widgets/pdf/download/article/3796
How was the operation carried out in the silo plant?
Our specialists entered the silo using rope access technology that has been tried and tested more than a thousand times in practice (see pictures). With the current cooler outside temperatures, wearing full protective equipment is no problem for the well-trained employees.
These factors are decisive when preparing the blasting:
• Drilling system with perfectly pre-calculated position of the individual holes for the explosives and their compaction
• Choosing the right explosive and detonation method
• Earth fault and resistance measurement of the electric detonators as charge variables (see photo)
Every step is calculated in advance and is carried out precisely by the employees inside the silo. All activities were carried out strictly in accordance with the specifications of the exemplary safety concept.
The interior of the silo was abandoned by the team’s technicians. The blasting master then carried out the combination blasting with 18 detonated charges at intervals of 20 milliseconds. This blast succeeded in breaking up the silo blockage and efficiently shredding the material. The silo wall was not subjected to increased pressure during the process.
Proof of this was provided by the vibration measurement carried out simultaneously with the blasting on the inner walls of the silo system. Our job has been successfully completed. Both our team and the operator of the silo facility were delighted with the results.
CONCLUSIONS:
With “intelligent blasting technology”, material bridges can be dissolved in silo systems, compacted contents loosened up and hazardous areas removed. All this is done without compromising the structural safety of the silo system. A comprehensive risk assessment and a consistent, exemplary safety concept are crucial here. Both can only be implemented by professionals with decades of experience and expertise.
Well-known companies from a wide range of industries rely on the expertise of NT Service GmbH: https://tnt-reinigung.de/de/referenzen
