How are minerals extracted from the earth's surface?
Answers
by mining and then refining it
Extracting Surface Minerals
Surface mining is just what it sounds like - removing minerals that are near the earth's surface because this is where the ore deposits are located. When the ore deposits are very large, open-pit mining is utilized. A large, open pit is created as machines scrape off any earth that is not ore and set it to the side. This material is called overburden, and as the overburden is scraped off, it's piled into spoil banks.
After the overburden is cleared from the ore, explosives are used to break up the ore material that is being removed from the ground, which is then taken away to be refined. The size of the ore bed increases as mining continues, and eventually, the pit becomes a very large bowl-shaped hole in the earth's surface. When the ore is found in a wide area but it's not very deep in the ground, strip mining is used.
In strip mining, instead of creating one large pit in the ground, long narrow strips are dug out. The overburden is removed and piled up along the strip. Once the ore is removed, the overburden is dumped back into the strip. While this may sound like a good method because the holes are re-filled instead of left open, the land actually looks more like a washboard after strip mining because of all of the re-piled soil.