Cordtex is a type of detonating cord

Detonating cord

Detonating cord is a thin, flexible plastic tube filled with PETN . With the PETN exploding at a rate of approximately 4 miles per second, any common length of det cord appears to explode instantaneously...

 generally used in mining

Mining

Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

. It uses an explosive core of pentaerythritol tetranitrate

PETN

Pentaerythritol tetranitrate , also known as PENT, PENTA, TEN, corpent, penthrite , is the nitrate ester of pentaerythritol. Penta refers to the five carbon atoms of the neopentane skeleton.PETN is most well known as an explosive...

 which is inside its plastic coating.

It is commonly the thickness of electrical extension cord

Extension cord

An extension cord, power extender, or extension lead is a length of flexible electrical power cable with a plug on one end and one or more sockets on the other end . The term usually refers to mains extensions but is also used to refer to extensions for other types of cabling...

 and "burns" at 2 km per second. It is used to "daisychain" a sequence of explosives together.

It can also be used in short lengths in simple boobytraps and early warning devices.