Energy from the Bowels of the Earth
By “Awake!” correspondent in Belgium
“I WORK in a coal mine.” When someone makes that statement, most people tend to view him with mixed feelings of awe and pity. Is not coal mining hard and dangerous? A few decades ago this was indeed the case, but the increasing mechanization and progressively better safety regulations have resulted in favorable changes.
In Belgium coal miners certainly appeal to the imagination. Representations of them are even stamped on coins. And no wonder, because during the boom period 150,000 persons were working in the coal mines, a great number indeed for one of the smallest countries in Europe.
Coal basins can be found in northern as well as in southern Belgium. Not everyone realizes that outsiders can visit these mines on certain days, accompanied by qualified guides. I have many friends who spend a large part of their lives in the bowels of the earth. This was enough for me to go down once myself. Perhaps you would like to join me on this educational journey.
This is Beringen, a coalfield in the northern basin. Since coal is found almost exclusively at great depths (approximately 800 m, or 2,600 ft.), shafts are needed in order to reach the layers of coal. Everything takes place along these shafts—the transportation of personnel, equipment and coal. The shafts also house plumbing, electric wiring and pipes with compressed air.
Uninformed persons sometimes think that drilling a shaft involves nothing but digging a hole deeper and deeper and carrying off the dirt. It is not that simple. The various layers that have to be drilled through at times consist of quicksand, loose rock formations and water, all of which could easily make the shaft collapse. To prevent this an ingenious system is put into operation. Some 40 boreholes are made right down onto solid bedrock around the spot where the shaft will be. Into each of these holes two pipes are placed, through which a cooling liquid brine at −25° C (−13° F) flows down and back up. Everything gradually freezes. After three or four months a large cylinder of frozen ground is obtained in which the actual shaft is made and reinforced with cast-iron rings.
An Underground Visit
Before we descend into the mine each visitor is given part of the typical mine worker’s equipment: a lamp, a helmet and a CO (carbon monoxide) mask. In mere seconds we reach our destination, 789 meters (2,588 ft.) down. We do not yet find any trace of coal. We see lit-up cylindrical tunnels going in different directions. The tunnels are covered with conically shaped concrete blocks. Our guide tells us that this covering best resists the tremendous pressure.
These tunnels are called “stone corridors.” They are of greatest importance because they unlock the underground. Starting out at the shaft they spread in different directions and penetrate the “concession field,” and from them the various layers of coal are bored. When we learn that the corridors reach a length of 90 kilometers (56 mi.) after about 50 years of exploitation, it does not surprise us that we have to board a small train to go to one of the eight “coal win” spots.
The ride bears some resemblance to a subway ride in a big city. At the same time it gives us the opportunity to ask our guide questions that have been on our minds.
“We have passed another story in the elevator—does that mean that there are two coal seams in this mine?” I ask.
“Not at all. Exploitation takes place in 11 different seams, but there are more. The layers are not horizontal but incline up to 14 degrees. The thickness varies from 80 centimeters to 2.7 meters (31 in. to 9 ft.). These layers of coal, along with the rock mass in between that consists of sandstone and shale, can be compared to streaky bacon tens of meters thick. The white fat is the rocks; the red meat, the coal.”
“Now I understand,” I said. “One set of corridors would not be enough to exploit all these seams easily.”
“That’s right,” answers our guide. “We are now 789 meters (2,588 ft.) below ground level. Sixty-two meters (203 ft.) above us there is another set of stone corridors. The coal is mined on these two levels. They start out from here and proceed toward the coal seams by way of sloping passages or galleries.”
We have now reached our destination. We walk some more through lit-up corridors and notice that a pleasant stream of air permeates them. Our guide explains: “All the fresh air is pumped through the shaft on this level. It reaches the corridors, mining areas and work quarters. The unclean air returns to the surface past the level just above us. Each year we take out about one million tons of coal.”
We leave the corridor now and arrive by way of a sloping section at a tunnel reinforced with arched iron bars. Right behind is wood. The miners call this type of corridor “galleries.” The guide draws attention to stone dust lying on planks just above our heads. In case of fire these planks can be tipped so that a dust cloud can put out the fire. This manner of fire fighting is aimed at coal dust whirling around that may catch on fire for one reason or another. Coal dust is very combustible, even explosive.
“Is risk of fire all that real?” I ask.
“It seldom happens, but because of the catastrophic dimensions that fire could take on, we have to take utmost precaution. The battle against dust has come a long way. Drills that spray water at the time of drilling and the highly pressurized water that is injected into the layers of coal are efficient means to combat dust.”
Where We Find Coal
We have reached the end of the gallery. We notice a narrow, low passageway about one meter (3 ft.) high and at right angles to the gallery where we are. On one side there is slanted rock against which a hydraulic support is pressed, and on the other side we finally see a low wall of shiny, black coal. This is the actual place yielding coal. We feel its surface. This layer of coal one meter thick is said to represent a layer of vegetation 25 meters (82 ft.) thick thousands of years ago.
“The exploitation of a coal seam,” the guide explains, “happens as follows: we start more or less at right angles to the stone corridors; with two galleries one must feel around a bit for coal. If one happens to have hit upon coal in both galleries, then the two are joined. This connection you see straight ahead of you and this is the actual place yielding coal, called the ‘pillar.’ These work quarters, 200 meters (656 ft.) wide, forge ahead into the coal seam. The coal is taken out in strata over the entire width. We could put it this way: the corridor, the galleries and the pillar constitute the four sides of a large, sloping, more or less rectangular piece of coal about one meter thick.”
I have a mental picture of a miner chopping away at the coal and ask if he still exists.
“Practically not,” our guide answers. “And we are not sorry, because dislodging coal with a pneumatic pick is very hard work. For the most part, the machine does this work now. Every day it chews meters of coal from the seam. The supports are moved over and the roof of the worked quarters is simply allowed to cave in.”
We are very much surprised. We had indeed noticed fallen rocks that had, as it were, come down from the ceiling. “Isn’t that dangerous?” I ask.
“No, the faults caused this way are negligible compared to the upper layer that is hundreds of meters thick. This is figured out mathematically by engineers. As a matter of fact, other methods are used, too. Sometimes, such dug-out premises are blown full of stones.”
We progress slowly. Two hundred meters (656 ft.) in a stooped position is a long way for my untrained legs. Thoughtfully I look at the long legs of a young miner in front of me and cannot help commenting that it seems to be an advantage in the mine to be small.
“On first thought, yes,” he laughs, “but you have to be able to turn a disadvantage into an advantage. Like this.” He bends low and with long, crablike strides he reaches the end of the passage in a minimum of time.
How Did the Coal Get There?
I wish to know more about the origin of coal. To this end I approach a guide. Willingly he explains: “It is generally accepted that coal got here as a result of catastrophes. When dead vegetation remains exposed to air, it decomposes. However, if vegetation is suddenly cut off from the air by water, clay or sand, there is said to be a coal-forming process. The exerted pressure and time are key factors. In the southern coal basin of Belgium many skeletons of prehistoric animals have been found—dinosaurs, and so forth. Relative to this I should like to mention that the only skeletons found are those of extinct or still-existing animals. No trace has been found of the millions of so-called intermediate forms among the different animal kinds, which should reasonably have existed according to the theory of evolution.”
The Mine Worker
One of the advantages of working in a mine is an early eligibility for pension, namely, after 25 years of service. In practical terms this means that someone who starts in the mine at 18 years of age retires at 43. In addition, the mine worker has numerous holidays that he can use at his own discretion. Then there are extensive social benefits such as free coal and low rents.
The danger of coal miner’s lung remains real. Especially damaging is the rock dust. This is because the molecular structure is angular as compared to that of coal dust, which is circular. Numerous ways to combat dust coupled with a shorter work term have, of course, lessened the danger.
“What about the danger of cave-ins?” I want to know.
“The real, natural mining disasters, such as cave-ins, explosions and fires, are rare. The ever-improving working conditions and safety regulations have had their influence. On the surface there is a gigantic control panel to register practically everything that could go wrong in the mine.
“One uninvited guest we have to deal with underground is blackdamp. As mentioned earlier, coal came into existence because masses of vegetation were cut off from the air. During the mining process, however, several other ingredients making up the plants are released. So one cubic meter of coal releases 350 cubic meters of blackdamp and 200 cubic meters of carbon dioxide. These gases are sucked away through inclining bores and recycled on the surface as a source of energy.”
I still have to ask the question that has preoccupied me since we started out: “For some, is it not a frightening experience to have to descend into the deep, cut off from the world above except for these two shafts?”
“You mean the element of fear,” he laughs. “That is practically nonexistent because this work is passed down from father to son. We know the mine and know no other way of life. It is similar to what happens in a fishing area where the son goes fishing just like his father. To put you at ease, I can tell you that besides these shafts there are other connections with the ground above. For emergencies, there are extra underground links with other mines in this coal basin.”
We now return to our starting point and whizz back up in the elevator. Everyone has had his chance to get himself very black in a short period of time. The black coal dust we wash off in the miners’ showers. What we cannot wash away, however, is the vivid impression made on us by our first visit deep in the bowels of the earth.
“Indeed, for silver there exists a place to find it and a place for gold that they refine; iron itself is taken from the very dust and from stone copper is being poured out. An end to the darkness he has set; and to every limit he is searching out stone in the gloom and deep shadow. He has sunk a shaft far from where people reside.”—Job 28:1-4.