How are Rocks, Ores & Minerals Extracted from Mines? (Cambridge (CIE) IGCSE Environmental Management): Revision Note

What is an ore?

• Ore is a type of rock that contains minerals and metals

  • The metal or mineral can be extracted and used for human purposes

• Metallic ores provide us with metals and alloys that we need to make everyday products like laptops, smartphones, cars, and batteries

• Examples of metallic ores include:

  • Iron ore for iron

  • Bauxite for aluminium

  • Copper ore for copper

• There are three main methods for extracting rocks, ores, and minerals from mines:

  • Surface extraction

  • Subsurface extraction

  • Biological extraction

Surface extraction

• Surface extraction is when rocks, ores, and minerals are removed from close to the Earth’s surface

  • It is also known as open mining

• Common methods include:

  • Opencast mining:

    • Also known as open-pit or open-cut mining

    • Large sections of worthless rock and soil (known as the overburden) are removed to reach the valuable material beneath

• Surface extraction is often cheaper and safer than underground mining

  • However, it can cause large-scale damage to the landscape and habitats

Subsurface extraction

• Subsurface extraction is when rocks, ores, and minerals are taken from deep below the Earth’s surface

• It is used when the mineral deposits are too deep for surface mining

• Common methods include:

  • Deep mining—tunnels are dug to reach the deposit, and workers remove the rock from below

  • Shaft mining—vertical shafts are dug down to access the mineral layers, with lifts or hoists to bring materials to the surface

• Subsurface extraction is expensive and dangerous

  • Risks include cave-ins, gas leaks, and poor air quality

  • It also requires ventilation, drainage systems, and strong supports to make it safe

Biological extraction

• Biological extraction uses living organisms to extract metals from ores

  • This process is more environmentally friendly and less energy-intensive than traditional mining

• Two main methods are:

  • Phytomining—plants absorb metal ions from the soil through their roots

    • The plants are harvested and burned

    • The ash contains concentrated metal compounds that can be processed to obtain the metal

• Bioleaching—bacteria feed on the minerals in the ore and produce a solution containing the metal ions

  • The solution is collected and processed to extract the metal

• Biological extraction is a slow process but it reduces pollution and can use low-grade ores that would otherwise be wasted