Under Ground – Part 7

Under Ground

Listen to Lee Dorsey’s 1967 hit, Working In The Coal Mine

Carl decided it would be best if he stayed at the face as much as he could and watch Pat run the continuous miner, and also watch Chuck to see what he did as Pat’s helper. The electric cable attached to the continuous miner was as thick as a small tree trunk.

He could see by the way that Chuck handled the cable, that it was pretty heavy. Chuck was tall, but he didn’t look like he’d be all that strong, and his struggles with the cable caused Carl to think that it wouldn’t be as hard for him to keep it out of the way as it was for Chuck.

The mining that Pat was doing was referred to as “driving” by the miners. When he’d worked at the other mine, the mining that Roy was doing was called “retreating.”

There’s a big difference between driving and retreating in coal mines. Retreat mining is more dangerous because in retreat mining, the crew intends for there to be big cave-ins, or “fall-ins” right where they were working just minutes before. This may sound insane, but it’s true.

It helps in keeping the crew safe.

When a mining crew is “driving,” they are busy cutting a grid of blocks through the coal vein, and if one could look from above at the entirety of the coal vein once driving has been completed, It would resemble a side of a Rubik’s cube, except all the squares would be black.

By cutting and loading the coal to create the blocks, tunnels through the coal seam were also created. Once all the blocks have been created, then driving is finished and it’s time to start the retreat mining.

Not every section goes right into retreat mining as soon as driving is finished though. It could be a while before they’d start retreating it, and the crew and equipment could be moved to start driving a new section, or even start retreating another section that had been sitting for some amount of time, and ready to go.

The blocks of coal that are created during driving, are actually great, strong supports for the mine roof. They’re like giant posts or roof bolts for the section they cover.

Retreat mining removes the big coal blocks, one by one. It starts, of course, where the driving part ends. When most of a whole block has been removed, hopefully, shortly after that, the section of the mine where the block of coal was, will all cave in.

The reason the miners want part of the mine to fall-in, (miners say “fall-in” but one can say fall-in, collapse, or cave-in; however one wants to term it), is because it releases pressure on the rest of the mine roof, which will also fall-in progressively, as each block is mined.

The idea is, the miner operator attempts to get as much of the coal block removed as he can, before there are signs the collapse is imminent and it’s time to back the machine out of harm’s way. As you may guess, there have been miner operators killed while in this situation.

Many more had to run to escape death, leaving the continuous miner to be covered with the collapsed roof.

To some miners, probably a majority of them, a miner operator who got his machine covered up more than once, was a real clown; an idiot.

Some of them, while working in retreat mining, had gotten their machine covered up more than once, or even twice. After a while it became easy to guess who had gotten their continuous miner trapped under fallen roof, just by knowing who was working that shift.

Carl hadn’t spent any time watching Roy doing retreat mining at the other mine. New miner operators however, usually didn’t do their first mining in retreat sections, so that wasn’t a big deal. He’d see retreat mining here also at some point, and he still had lots to learn.

One of the things Carl needed to learn, was roof inspection. When he’d see Pat tapping the roof with his sounding stick, he’d ask him questions, such as, “What are you listening for?” or “What have you determined from the sound of the roof?”

In retreat mining, knowing as much as one can about the state of the roof is critical. About a month after starting with this crew, Carl learned that the miner operator previous to Pat, was killed when a two-ton piece of rock fell on him. He was in his early fifties and had plenty of experience as a miner operator.

Finding this out made the section seem somewhat eerie. He’d seen death before, but trying to process what had happened to this miner and why, was difficult for him. Carl believed in fate. The miner operator had met his. He could only hope his would end differently.

When a mining crew was driving, there wasn’t a need to have lots of posts like Carl had to carry on his shoulders at the other mine.

In retreat mining, posts were used to support the roof rather than roof bolts. Because the miners want the section to fall-in when enough of the coal block has been removed, posts are used because they are easy to set in place, and they’re also easy to remove.

They also will not only bend, but break when the pressure becomes too much for them.

If roof bolts were used in retreat mining, they couldn’t be removed, and they would keep the roof from falling in for a longer period of time, which would put the miners in tremendous danger of a really massive fall-in, the time of which, no one would be able to predict.

A good miner operator could take out most of the coal block, and then knock out some of the posts by swinging the machine’s front-end left or right as he backed the machine out right before the fall-in would occur.

Once the machine was no longer in danger, they’d wait. Little pieces would fall, posts would creak and crack and become deformed, and then all hell would break loose, resulting in a job done well.

Here is a short video of coal miners, patiently waiting for a fall-in where an entire block of coal has been removed, and then the fall-in itself takes place. Make sure you turn up the volume to get the full effect!

_{Under Ground © free-reign 2020}

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Thanks for reading!

Sources for images used in this post:

Public Domain photos are from Wikimedia Commons:

_{Shift Over: The U.S. National Archives / No restrictions
Continuous Miner: Image by ENERGY.GOV / Public domain
Miner Under Rock: Image by National Photo Company Collection / Public domain}