The environmental impact of iron ore mining in all its phases from excavation to beneficiation to transportation and beyond may have detrimental effects on air quality, water quality, biological species, and nearby communities.Alderon Iron Ore Corp (2011): http://www.ecc.gov.nl.ca/env_assessment/projects/Y2011/1611/index.html.Iron Ore Company of Canada (2013) Wabush 3 Open Pit Mine Project in Labrador West: http://www.ecc.gov.nl.ca/env_assessment/projects/Y2013/1711/index.html.Labrador Iron Mines Ltd. (2010) Schefferville Iron Ore Mine (James and Redmond Properties): http://www.ecc.gov.nl.ca/env_assessment/projects/Y2010/1379/index.html. This is predominantly a result of large-scale iron ore tailings (solid wastes produced during the beneficiation process of iron ore concentrate) that are released into the environment which are harmful to both animals and humans.
Iron ore
Iron ore is a mixture of rocks and minerals containing enough iron content and sufficient volume and accessibility for mining and transportation to be economically mined. Around five percent of the Earth's crust is composed of iron making it the fourth most abundant element. Globally, iron ore is most commonly found in banded iron formations (BIFs) in the form of magnetite (Fe3O4), hematite (Fe2O3), goethite (FeO(OH)), limonite (FeO(OH)·n(H2O)) or siderite (FeCO3). Hematite and magnetite are the most common types of Iron ore. Roughly 98% of iron ore on the global market is used in iron and steel production. The other 2% of iron ore is used to make powdered iron for certain types of steel, auto parts, and catalysts; radioactive iron for medicine; and iron blue in paints, inks, cosmetics, and plastics. Countries rich in iron ore deposits include Australia, Brazil, Canada, India, China, and South Africa.
Mining and processing
Once a fertile site is located, iron ore is typically extracted through open-pit mining. Common extraction methods for iron ore are drilling and blasting. The ore is then transported for processing where it undergoes crushing before being put in a blast furnace where coke smelting converts the iron ore to metallic iron. This is a part of the beneficiation process where the ore is becoming ore concentrate. The gangue minerals become tailings and are transferred to a storage facility.
Issues
Iron mine tailings The high demand for iron necessitates continuous mining and processing, which generates a large amount of solid and liquid waste. Iron ore tailings are leftover materials that are released once mineral processing is complete. This waste includes large amounts of iron and manganese oxides in addition to high pH values. Potentially toxic elements found in iron ore tailings include Ba, Cr, Cd, Co, Cu, Fe, Mn, Pb, Ni, and Zn. It is estimated that nearly 32% of iron ore extracted ends up as tailings. Every year, approximately 1.4 billion tons of iron ore tailings are produced. Iron ore mining sites, as well as the wastewater tailings produced by them, contain high levels of dissolved iron and particulate suspended matter, which alter the water chemistry and metal bioavailability.
After leaving the mine, tailings need to be stored and managed in order to avoid environmental hazards and safety risks. In Brazil, approximately 95% of mining tailings end up in containment dams. Many countries have experienced dam breaks. In 2015, the city of Mariana in Brazil experienced the failure of the Fundão Dam. More than 30 million cubic meters of water and tailings from iron ore mining were released into the environment. Iron ore tailings dam breaks cause serious environmental damage and fatality in humans. Tailings impoundments also have the potential to seep. Seepage can be prevented or at least minimized by creating an impermeable layer. Otherwise, acidic and metal-bearing waters from tailings can affect aquatic habitats and nearby groundwater.
Air quality The main sources of emissions during both the construction and operation phases include the products of combustion such as nitrous oxide, carbon dioxide, carbon monoxide, and sulfur dioxide and fugitive dust from the operation of equipment. The main sources of combustion-related emissions during both the construction and operation phases are related to diesel generators, fuel-oil boilers, and on-site road traffic. Fugitive dust emissions can occur during land clearing, ground excavation, and equipment traffic on site. Potential sources of fugitive dust during operation include ore loading and unloading, ore crushing, stockpile erosion, and dust from conveyor systems around the site. Fugitive dust emissions are proportional to the disturbed land area and the level of activity and vary substantially from day to day with varying meteorological conditions. The major effects of industrial air pollution on wildlife include direct mortality, weakening industrial-related injury and disease, and physiological and psychological stress.
Gas and particulate emissions from historical smelting operations have been a source of concern for human health and environmental impacts at some sites. Modern smelters use processes that drastically reduce particulate and sulfur dioxide emissions, recognizing the importance of minimizing and mitigating this impact. Historically, sulfur dioxide was the most common source of concern because it reacts with atmospheric water vapor to form sulfuric acid, also known as acid rain. The acidic conditions that develop in the soils where these emissions precipitate can harm existing vegetation and inhibit the growth of new vegetation. The environmental impact of historical smelting has left barren areas near smelting operations. Some areas that have been impacted for decades are now beginning to recover. Emissions from older metal smelters may have harmed human health in some cases. During the operation of lead-zinc smelters, for example, elevated levels of lead in blood have been measured in residents of some communities located near the smelters. Smelting operations are now combined with environmental controls to prevent potential environmental and health issues related to emissions.
Acid rock drainage Acid rock drainage is created when water and oxygen interact with sulphur-bearing minerals and chemicals in rocks. Sulphuric acid is the most common chemical reaction that results from mining activities as the beneficiation process requires dissolving the minerals surrounding the ore, which releases metals and chemicals previously bound up in the rock into nearby streams, freshwater bodies, and the atmosphere. Acid is most commonly carried off the mind site by rainwater or surface drainage. Many metals become mobile as water becomes more acidic and at high concentrations these metals become toxic to most life forms. Approaches to preventing and cleaning up acid mine drainage include reclaiming contaminated land, soil removal, direct treatment, filling in abandoned mines, relocating and isolating waste, bacteria control, diverting water, and disposing mine waste underwater.
Wetlands and flora
Some mines require the draining of nearby wetlands for the beneficiation process and the cooling of project machinery, which affects downstream water quality and water quantity, and flora and fauna. Wetlands include bogs, fens, marsh, swamps, and shallow water. Wetlands serve a number of functional purposes in the biosphere such as collecting and storing surface runoff, moderating stream flows, reducing natural flooding and erosion, cleaning and purifying water, recharging groundwater zones, and providing habitats for plants and animals,.Department of Environment and Climate Change. (n.d.). Policy for Development in Wetlands | Water Resources Management. Retrieved March 2, 2017, from http://www.ecc.gov.nl.ca/waterres/regulations/policies/wetlands.htmlGroup, N. W. (n.d.). Retrieved March 2, 2017, from http://www.water.ncsu.edu/watershedss/info/wetlands/wetloss.html Wetlands are being altered from their natural state to support alternative land uses such as agriculture, urbanization, industrial development, and recreation. Megafauna Some animals are more susceptible to change and degradation than others Megafauna, including large mammals such as black bears, caribou, and wolves, have shown notable behavioural changes and is sensitive to noise levels caused by iron ore mining and infrastructure projects shortly before and immediately after the young are born and during the rutting season.Department of Environment and Climate Change. (n.d.). All Species. Retrieved March 2, 2017, from http://www.ecc.gov.nl.ca/wildlife/all_species/index.htmlWebster, L. (1997, August). caribou Region Wildlife. Retrieved March 21, 2017, from http://www.env.gov.bc.ca/cariboo/env_stewardship/wildlife/caribou/mtncar/harass/impacts.pdf These disturbance types increase the distances moved by the animals and may effectively decrease reproductive success and cause starvation. In addition, mining development means new roads and trails are needed for access which greatly impacts wildlife. Animals lose their habitats and are made susceptible to overexploitation, interrupted migration patterns, and lower population sizes. It also affects the abundance of food available for these animals since open-pit mining requires the removal of topsoil and vegetation which diminishes biodiversity.
Water quality Water is one of the major natural resources that is being polluted by iron ore mining operations. In order to achieve sustainability, Earth's streams, rivers, lakes, and oceans must remain uncontaminated.
The extraction of iron ore can cause surface runoff and leachate leading to the pollution of nearby water bodies. Iron ore mining pollutes water through metal contamination and heightened sediment levels in streams. The risk of contamination increases when iron ore mining exposes metal-bearing ores rather than exposing ore bodies naturally through erosion and when mined ores are placed on earth surfaces in mineral dressing processes. In the case of Iron Mountain, remediation activities took place in 1990 and water samples taken from seeps came back with negative pH values and were considered the most acidic water ever sampled. Mining can also have an effect on water before the extraction process. During exploration, roads may be poorly built resulting in sedimentation which disrupts water quality. Overall, water quality can be impacted as a result of acid mine drainage, heavy metal contamination and leaching, processing chemicals pollution, and erosion and sedimentation.
Indigenous communities The above environmental issues of iron ore mining have disproportionate impacts on Indigenous communities and they remain vulnerable to mining's impacts as a result of their close relationship to the land, water, and other natural resources. According to a study from Spain's Autonomous University of Barcelona, mining has been the cause of 24.7% of environmental conflicts involving Indigenous peoples despite making up only 6.4% of the global population.