Feb 07, 2023
It is new puzzler time over at Car Talk.
Here we go.
Some years ago my wife and I took a trip down the east coast, from Boston all the way down south. So during that drive, somewhere around the state of West Virginia, I got the notion that I wanted to take a detour and explore an abandoned mine. They have all those old coal mines down that way. So we stopped and I hired a guide to take me through a couple of these old abandoned mines.
So this guide takes me through a couple of mines. So my only experience with mines is what I know from those old westerns where the mines, the walls, and the roofs of the mines were shored up with timbers. And I was very surprised to find out that they still did that, at the time. Maybe they don't now, I don't know. But they did then.
So, I asked the guide what kind of wood they used for the walls and roofs, and the timbers we were looking at. Because I didn't recognize it. And he said he didn't know any specifics about how they built the mines, he just knew how to get in and out, and give tours walking through it.
I walked through a few other mines in the area and they all seemed to have the same sort of wood used in the tunnels to shore up the mine themselves. I would have thought they would have used oak or ash, as those are very strong types of wood. But no. People in the area said they thought it was the tulip poplar that was used. And apparently, poplar is the only type of wood they use to shore up these mines.
So here is the question.
Why do they use poplar for this? Why wouldn't they use a stronger wood like oak or ash?
There's a very good reason why only this kind of wood is used.
Why?
Answer time for this puzzler about wood. Types of wood used in the mines.
I really would have thought they would have started using steel or something like that. But no, still wood. Poplar, like they did in the old Westerns we used to watch on TV as a kid.
Now remember, this was a long time ago. So maybe they don't use this these days. But then, it was tulip poplar that they used. And the question was, why did they use that wood instead of something stronger like oak or ash?
And here is the answer.
When tulip poplar begins to buckle under the weight of the coal or the dirt or whatever they are mining, it cracks loudly. A very loud noise comes from the poplar. Many stronger woods would give no noise when it was about to give out. In fact, they other woods crack and break at the same instant.
This poplar wood evidently has the characteristic that when it begins to strain, to stretch, it begins to emit loud cracking noises which serves as a warning to the miners that a collapse is coming, and they have time to get out.
