Wednesday, 16 July 2008

Underground Mining - PART 4

(Return to – PART 1, PART 2, PART 3)

After the first week the boss must have figured I wasn’t a total loss. He started teaching me how to run the rig. It’s a powerful piece of equipment that demands respect and a good ear. Not that you could hear much. The rig was so loud we wore earplugs and earmuffs over them. It was like going to a Heavy Metal concert 8 hours a day, every day. The vibrations actually loosened one of my fillings. Hate to think what it was doing to the rest of me.

The rig shouldn’t be that loud but we’d ripped off the silencer box to relieve back pressure and stop the rig from freezing. There was so much water in the compressed air the rig motor would ice up and slow down. Even running the exhaust hose was a pain. You had to be careful near the end of it as the ice would build up until the rig coughed up a ball of slushy, oily ice and fired it down the drive. The icing up problem got so bad we took the exhaust hose off. That baby really started to howl then. The whole mine could hear it. We got a reputation in one mine as ‘The Moaning Cow crew’. That's what they reckon it sounded like, resonating down kilometres of drives.

Tuning in to the rig is like learning a foreign language. There’re subtle sounds and vibrations that would tell you what it was saying. I could lay a hand on the rig and feel what the diamond bit was doing by the vibrations sent back up the rods, even when it was hundreds of metres down the hole. We only had a single gauge to watch. The pump’s pressure gauge. That erratic jerking needle could tell you many things. Little fluctuations warned of the bit bogging in or the core wedging in the barrel. The other indicators we used were the colour of the cuttings coming out of the collar, the rigs stance and sound of the exhaust. It was all hands-on gut-feel stuff. I started to pick up on tell tale warning signs and could correct problems before they occurred.

To really throw me in the deep end the boss would get the rig going then disappear for a crap or a look around the drive. Later he told me he’d duck around the corner and turn off his cap lamp then come back and watch how I’d react. Always did wonder how he’d reappear just as the pump pressure rose or the rig loaded up. It’s a training method I used on my offsiders later.

(Like it? See - PART 5)

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