AIRBREAKER

Series

Series Name

Mining Review 11th Year

Issue

Issue No.

8

Date Released

Apr 1958

Stories in this Issue:

1. 1SHOTFIRER
2. 2MANSFIELD WOODHOUSE
3. 3NAILBREAKER
4. 4AIRBREAKER

Story

Story No. within this Issue

4 / 4

Summary

BFI synopsis: large coal produced by means of a No.8 nail and air under high compression.
NCB Commentary - At Rossington Colliery, Yorkshire, a new installation is blasting down large coal.
Here’s a load on its way. It was brought down by a No. 8 nail and ordinary air under high compression.
That nail’s a lot thinner than Harold Cope’s No. 2.
Here are the elements of the system.
This air compressor, sited underground, at some distance from the coal face, is sucking in free air and squeezing it up though six stages to 12 thousand pounds per square inch pressure.
Air is sent to the coal face along steel lines.
There’s a quarter of an inch solid steel on all sides holding in check a pressure of air powerful enough to knock a hole through you or me.
At the face the steel line gives place to a wire reinforced rubber hose. There’s a pressure gauge and the rubber line ends in a steel shell.
Looking inside the shell you’ll see that a piston is free to move and expose air vents around the sides. An ordinary medium sized nail holds the piston in place.
Back underground, the face is being pre-cut. At Rossington they cut the middle and the top of the coal.
Now shot-holes are drilled - they’re rather larger diameter than usual.
A steel shell, with a nail in place, is inserted into the prepared shot-hole. There’s no need for stemming.
Normal shot-firing precautions are taken expect that since there’s going to be no explosive used there’ll be no hazard from gas ignition.
Now the air pressure is onto the shell. In a few seconds it builds up high enough to shear that No. 8 nail.
The explosion you just saw was caused simply by the release of compressed air at thousands of pounds pressure.
This new system is safe and economical. The shell can’t fly out of the hole and the Airbreaker, as it’s called, produces larger coal with less dust. They’re ready to fire again at once.
Here’s the proof - large coal being loaded off the face at Rossington.
It’s all done without explosives, through the invisible power of the air we breathe.
The Airbreaker is being used in stone too. Advancing the ripping lip is just another instance of the flexibility of this system.

Researcher Comments

Commentary recorded 10th March 1958.

Keywords

Mining; Engineering; Fuels

Written sources

British Film Institute Databases   Used for synopsis
Film User   Vol.13 No.147 January 1959, p27.
The National Archives COAL 32   /12 Scripts for Mining Review, 1956-1960

Credits:

Production Co.

Documentary Technicians Alliance

Sponsor

National Coal Board