Chapter 23. Chapter 23: Coal
What methods are used to mine coal...?
Guiding Question 23.3
What methods are used to mine coal, and what are the advantages and disadvantages of each?
Why You Should Care
When new resources are discovered, humans follow a typical pattern and start by harvesting the resource where it is easiest to get to—closest to the surface is the rule of thumb for any resources belowground. With coal, this meant we mined the deposits that were closest to the surface and followed the thickest layers into the mountains.
Today, we are left with the deeper and thinner layers of coal, and techniques to mine it have delved deeper and farther into mountains. These techniques will yield coal but at higher costs, as tunnels grow longer and more dangerous for the miners.
A new technique involves removing the rock layers directly and mining the coal from above. This is called mountaintop removal and is comparatively safer for the miners and cheaper for the company. However, it carries a great cost for the surrounding forested ecosystems and private lands and, consequently, is very controversial.
Test Your Vocabulary
Choose the correct term for each of the following definitions:
| Term | Definition |
|---|---|
| The rock and dirt removed to uncover a mineral deposit during surface mining. | |
| Water flowing past exposed rock in mines that leaches out sulfates. These sulfates react with the water and oxygen to form acids (low-pH solutions). | |
| Sites where tunnels are dug underground to access mineral resources. | |
| Removing dirt and rock that overlays a mineral deposit close to the surface in order to access that deposit. | |
| Surface-mining technique that uses explosives to blast away the top of a mountain to expose the coal seam underneath; the waste rock and rubble is deposited in a nearby valley. |
1.
What are the removed rock layers called?
| A. |
| B. |
| C. |
| D. |
4.
How does coal mining create acid mine drainage?
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