Destruction of Habitat
To get at the mineral wealth just below the surface, the entire area needs to be stripped of all vegetation and natural animal habitats. For example, Brazil has some of the largest open pit mines in the world which have been created by removing thousands of acres of rain forest which sustained countless numbers of animal species.
Extended Destruction
Mines do not tend to be situated near centers of population, so miles of access roads need to be built to and from the mine. This means there is habitat destruction for hundreds of miles around the mine, not just at the mine itself. Due to this remoteness, towns are also built near the mines to house workers.
Carbon Emissions and Fuel
Mining requires machines to dig out the minerals, large trucks to take them away and further machines to process the resource. These all run on carbon-based fuels which lead to emissions. This contributes to global warming and has unknown effects on the local area. Charcoal is often used as a fuel for some machines, and although it is not as polluting as oil and coal, it does require the felling of trees to make the fuel. This causes even more destruction to local habitats.
Water
Machines need to be cooled, and workers require water to drink. This leads to exploitation of local water sources, as bringing water in is uneconomical. This can lead to water shortages in the area, meaning there may not be enough for all the animals and plants to use.
Chemical Use
The mining of minerals involves the use of harsh chemicals to extract it from the rock. These chemicals seep into the soil which makes it harder for anything to grow and can leach or run off into water sources which poisons animals and plants.
Erosion
Digging these vast pits destabilizes the area's rock structure, which can lead to landslides. The removal of trees can also lead to flooding and further erosion as the tree roots are vital to holding the soil together.