Hobbies And Interests
Features
Open pit mines are dug using electromechanical shovels, which can load up to 100 tons of minerals at once, as well as controlled multi-motor crawlers and other large pieces of equipment. For those mines that are expected to be functional for long periods of time, it's common to build tracks for a small railway to go up and down the sides of the mountain.
Identification
Open pit mines are usually large excavations, sometimes reaching hundreds of feet in depth and diameter. When pit mines are dug, they are done so in stepped walls, so the machines and workers can make their way down without the need for additional equipment. This also prevents loose rocks from falling hundreds of feet to the bottom of the pit.
Geography
Countries with large mountain or deserted areas are more likely to have open pit mines. In the U.S., Montana, New Mexico and Arizona have the most open pit mines. Hibbing, Minnesota has the world's largest open pit iron mine. The largest open pit gold mine is in Indonesia.
Function
The most common minerals extracted from open pit mines are gold, nickel and copper. In smaller quantities, but equally profitable, are open pit mines of clay, coal, diamonds, limestone, iron and gypsum. Open pit mines from where building materials are extracted are known as quarries. Gravel, marble, sandstone and slate are the most popular.
Effects
After being completely mined, open pits need to be rehabilitated, meaning the area needs to be flattened out, covered with soil and stabilized. This is to prevent cave-ins in the area but also to avoid sulfuric acid, a common by-product of mining, to escape into the air. Fences are usually built around the closed pits to avoid animals and people from venturing nearby.