Fig. 7.1 shows a cross-section through an open-pit mine. Mining is the extraction of valuable minerals and other geological materials from the Earth. The de...

(a) An ore is a naturally occurring rock or mineral from which a metal or other valuable substance can be economically extracted. [1]

The key word is "economically": many rocks contain traces of metals, but only those with a high enough concentration to be profitably mined and processed are classified as ores.

(b) Two environmental impacts of open-pit mining: [2]

• The excavation removes all vegetation and topsoil from a large area, completely destroying the natural habitat and displacing wildlife. This leads to a loss of biodiversity, as species that depended on the original ecosystem can no longer survive there. [1]
• Mining operations generate large quantities of dust and noise, polluting the air and disturbing both wildlife and nearby human communities. Heavy machinery, blasting and the transport of rock produce continuous noise, while fine dust particles can cause respiratory problems and settle on surrounding vegetation. [1]

Other acceptable answers include: water pollution from acid mine drainage (when sulfide minerals in exposed rock react with rainwater to produce sulfuric acid), visual pollution and landscape scarring, or contamination of soil with heavy metals.

(c) How the mine site could be restored after extraction: [2]

• The pit could be backfilled with waste rock and overburden, then covered with a layer of stored topsoil. Native vegetation (grasses, shrubs and trees) can then be replanted to restore the ecosystem. Over time, wildlife will recolonise the area as the habitat recovers. [1]
• Alternatively, the pit could be allowed to fill with groundwater to create an artificial lake. The surrounding land can be landscaped and planted to create a recreational area, nature reserve or wildlife habitat. This approach can provide long-term community and ecological benefits. [1]