Kochi: Four types of explosive items would be used to demolish the four apartment complexes at Maradu in Kerala's Ernakulam district on January 11 and 12. The demolition of the flat complexes were ordered by the Supreme Court in May 2019 for violation of Coastal Regulation Zone (CRZ) norms.
The four explovise to be used for the demolition include emulsion, shock tube detonator, detonating fuse, and electric detonators.
When the exploder, kept at the blast shed 100 metres away, is operated, power would be conducted through the detonators and the explosion would occur.
1. Emulsion
'Super power 90' emulsion of the Nagpur-based Solar Explosives would be used to demolish the Maradu flats. Ammonium nitrate is the main constituent of the explosive. The emulsion explosive may be used for explosions even if it is in a wet state.
2. Shock tube detonator
Non-electric detonators or shock tube detonators are the main explosives being used for the demolition. Instead of electric wires, hollow plastic tubes would be used for combustion.
3. Detonating fuse
Detonating fuse is a thin and flexible plastic tube, which would be filled with pentaerythritol tetranitrate (pentrite).
4. Electric detonators
These are delay electric detonators that can determine the time for explosion. The explosions of various floors can be timed with a time gap of milliseconds.
Exploder
The blasting exploder is the switch used to conduct electricity through detonators. These would be set up at a shed, 100metres away from the flats.
Explosions not at once
Explosion on various floors would be carried out within a gap of milliseconds. Authorities have planned to carry out powerful explosions in the first phase and less powerful explosions in the second phase.
For example, the first explosion would be carried out only on the ground floor of the Holyfaith H20 flat. After 17 milliseconds, the next explosion would be carried out on first floor. After 25 milliseconds, next explosion would be carried out on the fifth floor and eighth floor. The explosions on 11th and 14th floors would be carried out after 200 milliseconds. All the explosions would be carried out within 200 milliseconds. The whole building would be razed to the ground within 45 seconds.
Building rubble in backwaters
There are apprehensions whether the rubble from the demolition of the Alfa Serene, Nettoor, would fall into the backwaters near Kundanoor bridge. The pollution control board has set up special equipment to assess the contamination.
Authorities have planned to make the Alfa Serene collapse at an angle of 45 degree. This flat has two towers. The debris from the second tower is more likely to fall into the backwaters. Also, there are more houses adjacent to the second tower.
The controlled explosion has been envisaged in such a way to prevent the debris from falling on to the houses. The attempt is to make the debris fall into the space between the twin towers.
However, most of the debris from the second tower would be made to fall towards the side of the backwaters. Authorities gave permission for this after it was said that the debris falling in the waterbody can be removed later. However, authorities have not given a clear picture on how much debris would fall into the backwaters.
Efforts would be made to reduce the amount of debris that would fall into the backwaters. Demolition expert A B Sarwate had earlier said that two to three per cent of the rubble would fall into the backwaters during the time of the explosion. However, as per the current plan, more rubble is likely to fall into the backwaters. There is apparently no other option to prevent the debris from falling on the houses.
Explosives loaded at Jain Coral Cove
The process of loading explosive materials into the Jain Coral Cove has been completed. About 395kg emulsion explosive materials have been loaded into 2,060 holes. Around 15,000-metre detonating fuse would be used to cover the explosive materials.
The process of filling explosives at the Holyfaith H20 was completed some days ago. Explosives were also filled in Alfa Serene.
The process of filling explosives at the Golden Kayaloram, the last flat to be demolished, began on Tuesday. Only 15kg of explosives would be needed to fill the 900 holes at this flat.
With this, all flats would be readied for explosion. Electric detonators would be connected to the explosive materials, only the day before the demolition due to safety reasons.