Self Rescuer

In 1979 I was introduced to the concept of stress analysis on the huge 70mm and 90mm plate hydraulic roof supports that needed to be strong enough to support hundreds of tons of rock, a mile or more under the ground, so rudimentary stress work was part of the job.

They also had a secondary hydraulic action that would "walk" them forward as the coal face advanced, a coal face would consist of thirty or more such roof supports attached together and after each pass of the massive cutting tool, the line would be manually advanced and "snaked" forward.

The roof would then collapse behind the line of supports.

As part of our training our Project Engineer, Jeff, took a few of us down the pit to see this in action, it was perhaps the most anticipated and exciting day of my young life and quite serious stuff.

Weeks before we had been on the "self rescuer" course, a breathing device that would filter carbon monoxide for a period that was deemed long enough to save your life. It was a prerequisite for anyone entering a mine that a valid certificate of training was required, and to achieve this, bad things had to happen...

If you were slightly claustrophobic, it would never happen, because the final test, after some classroom work, was to be locked in a maze type structure, pitch black and filled with smoke. The only source of illumination was from our helmet lamps.

In addition, objects had been left on the floor and there were a couple of tight squeezes between sectors. I don't know if this was intentional, but the place was hot and of course, breathing was laboured as we sucked air through our carbon filters.

Even though you knew there was no carbon monoxide in there, the test was quite mindbending and it was an absolute pleasure to see sunlight at the end of it all.