Adverse Ecological Effects of the Mirador Open-Pit Copper Mine
The World Bank notes that acid mine drainage is one of the most serious and difficult problems associated with mining, and has severe and permanent effects on the environment.
Acid mine drainage continues to emanate from mines in Europe established during the Roman Empire prior to 467 AD (CSS, 2002). Georgius Agricola’s “De Re Metallica” (1556), the first and seminal treatise on mining exhibits detailed woodcut illustrations not only of the known mechanics of 16th Century mining, but also depictions of the devastation of streams.
Acid Mine drainage is unavoidable. Whenever sulphide rocks are mined and they are exposed to the air and the water, they produce sulfuric acid. This in turn dissolves heavy metals in the rock.
In the Environmental Impact Assessment accepted by the Government and created by “Walsh”, he says that the Rivers Wawayme and Tundayme will be directly impacted by the Mirador Mine, and that these rivers are part of “a complicated, dynamic river system leading to the River Zamora, which in turn flows into the Amazon basin”.(Walsh, EIA 2010, 126.96.36.199).
Minerals such as cadmium, copper, zinc, arsenic, and selenium will be released. These heavy metals, after treating the acid water with lime to reduce the acidity, will precipitate as sediment, forming a sludge containing hazardous chemicals potentially lethal to all life forms and the eco-system.
Conservation International say that the most diverse plant communities known to science occur in this zone and that a year round abundance of water seems to be a key to this wealth of plant life.
In the Environmental Impact analysis Walsh rates contamination from acid mine drainage and heavy metals at 4.2 during the life of the Mirador mine and at 4 on closure of the mine. The highest and most dangerous rating is 5.
The forest will be annihilated over an area of at least 2,000 hectares. The implementation phase of the project during the clearing of vegetation for the opening of the mine and tailings, will result in the total removal of the habitats of species of amphibians and reptiles in the area.
The cycle of rainfall will be reduced. The rainfall cycle is very rapid with transpiration and water directly evaporated from the vegetation returning three quarters of the rainfall back to the atmosphere within 24 hours.
Waters, borne of the vegetation and filtered by the vegetation, are the ecological lifeblood of the forest and of the people who live from the forest and from the rivers.
When these impacted rivers are used for farming areas, or are used as a means of direct consumption for humans, both by the eating of fish, birds, or drinking of the water itself, people will also be affected by heavy metal pollutants caused by acid mine drainage. Bio accumulation of poisons will impact all food webs.
The Environmental Impact Assessment says that poisoning of watercourses will definitely occur.