Coastal and offshore mining activities that can have an impact on the marine and estuarine environments include: sand and gravel mining for minerals, beach replenishment or industrial uses; oil and gas exploration and production; coral (limestone) mining; and diamond dredging. Terrestrial mining may also cause the release of metals and sediments to estuaries and the sea. The effects can be measured in the destruction of seafloor habitats and the alteration of the marine species diversity and productivity of an area, including commercial fish species.
Extraction of metallic mineral ores, and the refining and disposal of wates from metallurgical industries, cause significant local environmental problems, such as acid drainage. Air pollution during these processes includes dust from mining and acidic gases, carbon dioxide and other greenhouse gas emissions from smelting, refining and other kiln operations.
Mining and quarrying are noisy, and may use blasting techniques causing noise pollution and driving off wildlife.
Abandoned hard rock mine sites may affect public health and the environment due to releases of hazardous substances from waste materials and acid drainage. Many streams and ground water reserves have been seriously affected by acid runoff and releases from abandoned coal mines. In many areas, entire watersheds are unable to support aquatic life and present hazards to the public.
Both active and abandoned coal mines sometimes fill with water, which becomes highly acidic, thus mobilizing heavy metals. During heavy rains, the water may overflow, and downstream water courses may become seriously polluted.
More than 60 North American, European, Japanese and South African mining companies joined the gold rush in the Guiana Highlands of Brazil and Venezuela, where as much as 10% of the planet's gold reserves may lie. Since 1991, the Corporacion Venezolana de Guayana, the agency of Venezuelan state that oversees the forest, has handed out more than 1.4 million hectares in mining concessions.