The short answer
Ordinary electric detonators have been prohibited in India since 1 July 2025: their manufacture, possession, sale, use and import are barred by a central government notification, with narrow exemptions. Quarry blasting now runs on non-electric shock tube systems, often called NONEL, and on electronic detonators. Shock tube is the everyday choice. Electronic detonators cost more per hole and time each charge precisely enough to cut vibration and improve breakage.
A detonator is the small charge that sets off the main explosive in a hole. How it is triggered, and how accurately it can be made to wait, decides more about a blast than its size suggests.
01What the notification did
The ban was first notified by the Ministry of Commerce and Industry in September 2023, to take effect from April 2025. After amendments during 2025 the operative date became 1 July 2025, and the prohibition covers manufacture, possession, sale, use and import. PESO directed licence holders to use up their stock before that date. Limited exemptions remain for specialised uses outside quarrying.
For a quarry or a highway cutting the practical position is simple. Electric detonators are not an option, and anything in a method statement, a licence or a store that still refers to them needs correcting. Check PESO's current notices before relying on any exemption.
02The systems now in use
| Shock tube (non-electric) | Electronic | |
|---|---|---|
| How the signal travels | A shock wave inside a thin plastic tube | A coded electrical signal to a chip in each detonator |
| How the delay is made | A pyrotechnic element that burns for a set time | A programmable electronic timer |
| Timing accuracy | Scatter of a few per cent of the nominal delay | Within a fraction of a millisecond |
| Delays available | Fixed steps, combined in the hole and on the surface | Any value, usually in 1 ms steps |
| Stray current and radio | Immune | Protected by design and coded firing |
| Can the circuit be tested before firing? | No, checked by eye | Yes, each detonator reports back |
| Cost per hole | Lower | Higher |
| Crew | Trained blasters | Blasters trained on that maker's system |
03Shock tube
A shock tube is a hollow plastic tube with a dusting of reactive powder on its inner wall. When initiated it carries a low-energy shock wave along its length at about two kilometres a second, without bursting the tube or disturbing the explosive it passes through. At the far end the wave fires a detonator.
In a typical bench blast each hole has a long in-hole delay, so that every detonator in the shot is already burning before the first hole fires. On the surface, connectors with shorter delays link hole to hole and row to row and set the sequence. The system cannot be set off by stray electricity, a lightning-charged atmosphere or a radio, which was the main weakness of electric firing.
Its limit is the delay element. Pyrotechnic delays burn at slightly different rates from unit to unit. A detonator marked for 450 ms may fire a few milliseconds early or late. Usually that is harmless. In a tight sequence it can let two holes fire closer together than designed.
04Electronic detonators
An electronic detonator carries a chip, a capacitor and a timer. The blaster programmes each one with its own delay from a handheld unit, the system checks that every detonator is connected and answering, and firing needs a coded command from the maker's blasting machine. The delay is counted by a clock, not burned by a fuse, so the scatter is negligible.
That precision is worth money in two situations. Near structures, vibration depends on the charge firing at one instant. If each hole is guaranteed its own instant, the charge per delay is exactly one hole, and the blast can be larger for the same reading. In hard rock, accurate timing between holes improves the way each one breaks to the next, which shows up as finer and more even fragmentation.
05Why accuracy matters for vibration
A vibration limit is met by keeping the explosive per delay under a ceiling. If two holes meant to fire 17 ms apart overlap because of scatter, the ground sees their charges together and the reading can be well above what the design predicted. With pyrotechnic delays, blasters allow for this by lowering the charge or adding margin. With electronic timing the margin can be used. The limits themselves are in controlled blasting near structures.
06What it means for cost
Initiation is a larger share of the blasting bill than it was with cheap electric detonators, and electronic systems raise it again. On open benches away from anything sensitive, shock tube is normally the economic choice. Where vibration is the constraint, the extra cost per hole is often recovered in fewer, larger blasts and less secondary breaking. The components of a rate are in drilling and blasting cost per cubic metre.
07Questions for a blasting contractor
- Which initiation system will be used on this job, and why that one?
- What in-hole and surface delays, and what is the designed time between holes and between rows?
- How is the hook-up checked before firing?
- Who has been trained on the electronic system, and by whom?
- What is the misfire procedure for this system?