The mining sector is responsible for some of the highest emissions of heavy metals into the environment of any industry. It also releases other pollutants from the air, such as sulfur dioxide and nitrogen oxides, in addition to leaving tons of waste, slag and acid drainage. Mine drainage is metal-rich water that forms from a chemical reaction between water and rocks containing sulfur-containing minerals. The resulting chemicals in the water are sulfuric acid and dissolved iron.
Some or all of this iron can come out as solids to form red, orange, or yellow sediments at the bottom of streams containing mine drainage. Acid runoff further dissolves heavy metals such as copper, lead and mercury in groundwater or surface water. The speed and degree to which acid mines drain can be increased by the action of certain bacteria. Forestry operations, such as logging, can generate significant amounts of pollution from non-specific sources.
Heavy machinery used to remove vegetation and trees exposes soil, increasing the risk of erosion. In addition, the inadequate construction and use of “landslide trails”, temporary trails used to transport logs out of the forest, can contribute to the contamination of non-point sources. Sliding trails that are built on the natural contour of a hillside are especially prone to erosion. During three years of operation, the company excavated 360,000 tons of ore and 94,000 tons of waste rock before leaving the mine in 1966.Mining generates millions of gallons of wastewater and, along with industrial wastewater and wastewater, is one of the main sources of water pollution.
For example, adding an open limestone channel can increase the pH by 0.5% of the mine's acid drainage, bringing 0.5% of AMD closer to the target. Some or all of this iron can precipitate to form red, orange, or yellow sediments at the bottom of streams containing mine drainage. Metals exposed in mines can leach when they come into contact with water and then be transported to the environment. Negative impacts can range from sedimentation caused by poorly constructed roads during exploration to sediment and water disturbance during mine construction.
Excess tailings “cakes” (pieces of tailings with almost no water) can be transferred to storage facilities or used to fill mines, that is, fill an abandoned mine with tailings. The Canadian mining industry generates one million tons of waste and 950,000 tons of waste per day, which means a total of 650 million tons of waste per year. Contamination by processing chemicals This type of contamination occurs when chemical agents (such as cyanide or sulfuric acid used by mining companies to separate the target mineral from the mineral) spill, filter, or leach from the mine into nearby bodies of water. In addition, when the mine closes, cleaning costs will be lower if the tailings compartments are lined.
Coho are particularly vulnerable to toxicity caused by acid mine drainage, since they reside in the system for up to 14 months after hatching. The impacts on the river began in the postwar era, when logging and irrigated agriculture moved to the watershed, gravel was extracted from the riverbed in the lower reaches, and then, in 1964, the Mount Washington Copper Mining Co. In the Mid-Atlantic and Appalachian regions of the United States, acid mine drainage and associated pollution from abandoned mines have also affected bodies of water. .
