Mining is the backbone of the economy – as valuable resources and geological materials are sourced from the earth. These resources cannot be fabricated or grown artificially, emphasising the need for mining to non-renewables such as fossil fuels and water.
The value that mining creates extends further than the extraction of minerals, as the miners themselves create economic value. This occurs through the establishment and integration of mining communities where people earn incomes providing goods and services in these towns, which creates revenue and allows infrastructure like schools, hospitals and more to be built.
The extraction method is dependent on various factors, these include:
- The resource being targeted for extraction
- If the deposits location is above or below the earth’s surface
- The capacity of each method to profitably extract the resource
- Degrees of safety
- Potential impacts on the surrounding environment
So, let’s understand each method.
#1 - Underground Mining
Mining underground is the method used to get access to deposits deeper in the Earth’s surface, which involves the creation of shafts and tunnels to reach the targeted resources. A relatively costly method, typically focused on mining buried ore that is brought to the surface to be processed, while waste rock is removed for disposal. Underground Mining is categorised based on the shafts used, extraction technique, and depositing process.
Drift mining requires horizontal tunnels
Slope mining uses diagonal shafts to access deposits
Shaft mining uses vertical access shafts
Utilising the appropriate method of mining is based on the amount of ground support to ensure safe mining and the surrounding geology of the operating area.
#2 - Open Surface Mining
Surface mining is used to access non-precious and fairly shallow deposits by removing soil, plant life and layers of bedrock in some cases. The following are the 2 foremost methods of surface mining:
Open-pit mining: Involves forming open pits where resources close to the surface are extracted from digging in the ground. These mines operate until the targeted mineral is depleted or becomes profitable no more. Often, this results in Open-pit mines being modified to become landfill for solid wastes. Water management systems are mandatory in order to alleviate risks of collapse and flooding of active mines.
Strip Mining: Commonly used to extract shallow deposits, when mineral layers are covered by layers of soft topsoil and weathered rocks. These layers of earth are then stripped by industrial shovels or a dragline to extract a deposit.
#3 - Placer Mining
Placer Mines operate in beach sands, riverbeds or other sedimentary environments. As a result, this method involves sifting valuable materials from sediments, usually formed by weathering such as wind or water action.
Gold, platinum, tin and other materials could be extracted through Placer Mining, with most of the world’s titanium stemming from this method of mining. For example, panning for gold is applicable to the Placer Mining process, as extracted sedimentary materials are rinsed and sluiced in order to obtain the targeted mineral.
#4 - In-Situ Mining (Solution Mining)
This method of mining does not require removing ore from beneath the surface of the earth. In-Situ Mining is most commonly used to mine uranium, because the process dissolves the targeted mineral, then processes it on the surface without removing any rock from the ground.
Solution mining causing minimal disturbance to the earth’s surface without producing large amounts of waste rock. To correctly carry out this method, the ore must be pervious to the chemical extraction liquid, whilst ensuring the process avoids the risk of contamination of nearby groundwater.
The successful implementation of the 4 main methods of mining provides the vital extraction of resources used every day. Mining supports local services and infrastructure by creating jobs and opportunities, supporting the economy and powering the nation.
The mining industry has adapted to contemporary values and sustainability goals necessary to preserve our planet, which we have covered in The Sustainability of Mining – A Guide to the Future.