The ecological impact of mining can be summarized as follows:
The actual gold winning technology uses cyanide to separate the gold from the less valuable ores. Cyanide is a highly toxic matter. The lethal dose of cyanide for human beings amounts to between 50 and 200 mg per person.
When cyanide is loosed into the environment, the heavy metals bound to the matter constitute the long-term problem: cyanide itself is quickly destructed, but the heavy metals stay in the environment for centuries.
Acid drainage is a serious problem in many metal mines, because metals like gold, copper, silver and molybdenum often appear together with sulphites. When acid drainage happens uncontrolled, the drainage water oozes through to streams, rivers and subsoil water. The acid water and the heavy metals are lethal to fish, other animals and plants and can be harmful to the environment for indefinite time after the closing of the mine.
The traditional image of mining, which consists of the deep subterranean exploitation of ores, does not longer correspond to present-day reality. Modern-day mining happens by means of bulldozers, which excavate rocks in an enormous open pit. During the digging of ores, a material is liberated which contains heavy metals and is easily picked up by the wind. In this way, the establishment of a mine can destroy the existing ecosystems.
The consequences of mining for the environment are not only problematic from an ecological point of view. Polluted soils and shortage of pure water make agriculture impossible. People who suffer health problems cannot work as long and as hard as they used to, which leads to the loss of income. Instead of fighting against poverty, then, mining makes poverty increase.