Glossary
Heap Leaching
A chemical process used to extract precious metals like gold and copper from low-grade ore by dissolving them with a chemical solution, typically cyanide.
Example:
After crushing the ore, it's often piled into large heaps where a cyanide solution is trickled through it for heap leaching, dissolving the gold.
Land Degradation (Mining)
The deterioration of land quality, including soil erosion, loss of fertility, and destruction of natural landscapes, often caused by mining activities and waste storage.
Example:
Extensive land degradation can be observed around abandoned mine sites, where vegetation struggles to regrow on disturbed and contaminated soil.
Mountain Top Removal
An extreme form of strip mining where entire mountaintops are blasted and removed to access underlying coal seams, causing severe environmental destruction.
Example:
The devastating impact of mountain top removal is evident in areas where once-forested peaks are now flattened, barren landscapes.
Open-Pit Mining
A mining technique that involves removing the surface layer of earth (overburden) to access minerals like gold and copper, creating a large, open hole in the ground.
Example:
To extract a large copper deposit near the surface, a company might use open-pit mining, digging a massive terraced crater.
Overburden
The soil and rock that lie above a mineral deposit and must be removed to access the valuable materials during mining operations.
Example:
During strip mining, excavators first remove the overburden—layers of dirt and rock—to expose the coal seam beneath.
Strip Mining
A surface mining technique where overburden is removed in long strips to extract minerals, commonly coal, from shallow deposits.
Example:
In the Appalachian Mountains, strip mining is often used to extract coal, leaving behind long, exposed trenches where the land was peeled back.
Tailings/Slag
The leftover waste materials, often in a slurry form, that remain after the valuable minerals have been extracted from ore during processing.
Example:
After gold is separated from the ore, the remaining muddy mixture, known as tailings, is often stored in large impoundments.
Toxic Substances (Mining Waste)
Harmful chemicals and heavy metals, such as mercury and arsenic, that are often present in mining waste and can leach into the environment.
Example:
Runoff from mine sites can carry toxic substances like lead and cadmium, contaminating local rivers and harming aquatic life.
Underground Mining
A mining method used to access mineral deposits located deep below the Earth's surface, involving the creation of tunnels and shafts.
Example:
Miners working in a deep gold vein often rely on underground mining, navigating a complex network of tunnels far beneath the surface.
Waste Rock
Rock material that is excavated during mining but does not contain enough valuable minerals to be processed, often stockpiled near the mine site.
Example:
Large piles of waste rock can be seen near many mines, representing the non-ore material that was removed to get to the valuable minerals.
Water Contamination (Mining)
The pollution of water bodies with sediments, heavy metals, and other harmful substances that leach from mining operations and waste.
Example:
Acid mine drainage is a significant source of water contamination, turning streams orange and making them uninhabitable for many species.
Worker Hazards (Mining)
The dangers and risks faced by individuals working in mining operations, including accidents, exposure to harmful dusts, and unsafe working conditions.
Example:
Despite modern safety measures, worker hazards in underground mining still include risks of cave-ins, explosions, and respiratory illnesses from dust inhalation.