Noiseless Trunkline Delays (NTD)-a type of Primadet® nonelectric delay detonator with delay times and hardware suited for trunklines in open pit mining, quarrying and construction.
Primadet® nonelectric delay detonators are nonelectric blasting caps using shock tube as a lead. Noiseless Trunkline Delays (NTD) are Pimadet® nonelectric delays detonators whose lengths, delay times and hardware suited for use trunklines in surface blasting. NTD’s are factory assembled units with five main components.
- Shock tube is a small diameter laminated plastic tube coated with a very thin layer or reactive material; only one pound of material per 100,000 feet of tube. When initiated, shock tube reliably transmits a low energy signal at approximately 6,500 feet per second from one point to antother. This shock wave phenomenon, which is similar to a dust explosion, will propagate trough most sharpe bends, knots and kinks in the tube. The detonation is sustained by such a small quantity of reactive material, the outer surface of the tube remains intact during and after functioning.
- The blasting cap, with an integral millisecond delay element, initiates detonating cord downlines or downline(s) of shock tube.
- The Bunch Block used to attach the blasting cap to the detonating cord or shock tube downline(s). The block containes the blasting cap with an integral delay element.
The delay tag indicates the nominal, end-to-end delay time of the factory assembled unit.
- The “J” Hook is an inert fitting at the initation end of the NTD, for quick and reliable connection to Primacord® detonating cord downlines or pigtails.
The Bunch Block and delay cap are attached to the output end of the NTD and when used are connected to the blast hole desired to be initiated. The opposite or initation end of the NTD has the “J” Hook and is attach to the downline or pigtail of the preceding blast hole.
The direction NTD’s are connected to the blast holes determines the sequence in which the blast holes will detonate. The choice of delay times determines the time interval between detonations.
Download : Primadet NTD
Adobe Acrobat (PDF) Format