2.6.2.1. Types of mining

The method of mining has to be determined depending on whether the ore or mineral deposit is nearer the surface or deep within the earth. Mines are of two types: a) Surface (open cut or strip mines) b) Deep or shaft mines.

Mining methods are chosen based on the location of the mineral deposits. If the minerals are close to the Earth's surface, surface mining methods are used; if they are located deeper underground, deep or shaft mining techniques are employed. This determination is essential because it affects how efficiently and safely the minerals can be extracted.

Imagine you’re trying to gather apples from a tree. If the apples are hanging low, you can easily pick them (surface mining), but if they are high up, you might need to climb the tree or use a ladder (deep mining) to reach them.

a) Surface Mining: Surface mining is used to obtain mineral ores that are close to Earth’s Surface. The soil and rocks over the ore are removed by blasting. Typically, the remaining ore is drilled or blasted so that large machines can fill trucks with the broken rocks. Surface mining includes open-pit mining, quarrying, and strip mining.

Surface mining involves removing the layers of soil and rock above the ore deposits through blasting. This technique is efficient for extracting minerals that are relatively shallow. After the top layers are removed, heavy machinery is used to crush and transport the ore to processing facilities. The main types of surface mining include open-pit mining, strip mining, and quarrying. Each method has specific applications based on the type of mineral and geography.

Think of it like digging a hole in your backyard. If you want to plant a garden, you first remove the grass and topsoil (just like removing rock and soil in surface mining) before digging deeper to plant your seeds.

1. Open-pit mining creates a big pit from which the ore is mined. The size of the pit grows until it is no longer profitable to mine the remaining ore.

Open-pit mining is a method where a large excavation is made to extract minerals. The process begins by digging a large hole, or pit, into the ground. As ore is extracted, the pit gets larger until it no longer holds enough economically viable ore for continued mining. This method is particularly effective for minerals that are near the surface, like copper or gold.

Imagine a giant bowl that you keep scooping ice cream from. Eventually, as you eat more and more ice cream, the bowl gets deeper, and you’ll reach a point where it's not worth digging for the last few scoops.

2. Strip mines are similar to pit mines, but the ore is removed in large strips.

Strip mining involves removing minerals in long strips rather than a deep pit. This process is particularly efficient for coal and other minerals that are located near the surface. The method starts by stripping away the topsoil and then removing the ore in sections. Once one strip is mined, the process moves to the next strip.

Think of strip mining like peeling a long ribbon of tape off a roll, where you take off one piece at a time instead of taking off the whole roll at once.

3. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings.

Quarrying is a specific type of open-pit mining aimed at extracting building materials like stone, gravel, and sand. It serves the construction industry by providing essential materials to build roads, homes, and other structures. Quarries are typically located where there are large deposits of rocks that can be economically extracted.

You can think of quarrying like gathering pieces of large stones from a rocky beach to build a sandcastle. Instead of pulling at the sand (which serves a different purpose), you focus on collecting the bigger stones that can help create your structure.

b) Underground Mining: Underground mining is used for ores that are deep in Earth's surface. For deep ore deposits, it can be too expensive to remove all of the rocks above the ore.

Underground mining is applied when the ore deposits are too deep to extract economically using surface methods. This process involves creating tunnels and shafts in the earth to access the minerals. Although underground mining is generally more complex and dangerous than surface mining, it is essential for accessing certain mineral deposits that would otherwise remain untapped.

You can compare underground mining to exploring a cave. Instead of just visiting the entrance (surface mining), you have to navigate through narrow and deep paths to reach interesting formations deep within.

For deep ore deposits, it can be too expensive to remove all of the rocks above the ore. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 meters deep (that is more than 2 miles)! There are various methods of underground mining. These methods are more expensive than surface mining because tunnels are made in the rock so that miners and equipment can get to the ore.

Accessing deep ore deposits involves significant costs and engineering challenges. The construction of tunnels must ensure miner safety and environmental stability. For example, the deepest gold mine in South Africa extends over 3,700 meters, highlighting the extent of investment and effort required for successful extraction. Furthermore, various techniques, such as room and pillar or longwall mining, are used, each suited to different mineral types and geological settings.

Imagine needing to build a staircase to reach a treehouse that’s very high up. It requires careful planning to ensure the steps are safe and can hold weight. Similarly, underground mining requires secure tunnels to ensure miners can safely dig for minerals without risking collapse.

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