The cause and effects of acid mine drainage

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The cause and effects of acid mine drainage

Copyright held by photographer Summary Acid mine drainage AMD refers to the outflow of acidic water from a mining site.

Acid mine drainage is a major problem with many hardrock mines, including almost all mines where the metal ore is bound up with sulfur metal sulfide mines. A significant number of coal mines also suffer from acid mine drainage.

The metals dissolved by the acid drainage poison downstream waters, in many cases to the point where nothing other than microbes can survive. Although mining is by far the largest cause of this type of acid leaching, the process can also occur during non-mining land disturbances such as construction, or even naturally in some environments, examples of the more general phenomena of "acid rock drainage" ARD.

Acid mine drainage is a worldwide problem, leading to ecological destruction in watersheds and the contamination of human water sources by sulfuric acid and heavy metals, including arsenic, copper, and lead. Once acid-generating rock is crushed and exposed to oxygen and the surface environment, acid generation is very difficult to contain or stop, and can continue for tens or thousands of years until the available sulfide minerals are exhausted.

Roman-era mines have been identified which are still producing acid mine drainage. It is the irreversibility of the process of turning relatively inert ore into tremendous volumes of hazardous waste, the very long hazard-life of the material, and the extreme difficulty of containment which make acid mine drainage such a serious and persistent issue.

Geology and chemistry Copper, gold, lead, silver, zinc, and other desirable metals are often found in ores rich in iron sulfide.

The cause and effects of acid mine drainage

They are isolated from the atmosphere and surface waters by their depth, providing relatively little surface area for them to react with water and oxygen. Acid formation in these buried deposits occurs at a slow and usually harmless rate.

Extracting the valuable metals from these rocks, however, involves extracting and crushing the ore. When iron sulfide is exposed to air or dissolved oxygen in water, the sulfide oxidizes to sulfate, which then turns to sulfuric acid H2SO4.

Sulfuric acid is a highly corrosive chemical, used in many industrial processes as well as in car batteries. It is also one of the primary constituents in acid rain, and is toxic to most living organisms. The sulfuric acid produced in sulfide mine tailings makes the surrounding water more acidic, sometimes dramatically so.

In addition to the direct effects of this acidity, acid water leaches toxic heavy metals such as lead and arsenic from the surrounding rocks into the water.

The mining process allows these acid and heavy metal generating reactions to occur at much higher rates than occur in nature. Metals mining produces waste rock and mine tailings with a surface area that is vastly greater than the undisturbed rock.

Extracting valuable metals from ore usually involves crushing the ore rock into a mud slurry, where each particle can be less than 50 millionths of a meter across. This increases the surface area of the sulfide rock by a factor ofor more, which proportionally increases the rate of acid formation.

The cause and effects of acid mine drainage

Theoretically, acid formation is neutralized where sulfide ores occur alongside more alkali minerals, since alkali a. Each alone is caustic, but combined they neutralize each other, like baking soda a base and vinegar an acid. Carbonate rocks limestone are a typical alkali mineral sometimes associated with sulfides.

Where acid and alkali minerals co-occur, the ratio of acid-generating material to neutralizing material is an important component of predicting whether a mine will have acid mine drainage.

This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the International Labour Organization, or the World Health Organization. Urban runoff is a major cause of urban flooding, the inundation of land or property in a built-up environment caused by rainfall overwhelming the capacity of drainage systems, such as storm sewers. Triggered by events such as flash flooding, storm surges, overbank flooding, or snow melt, urban flooding is characterized by its repetitive, costly and . Abandoned Acid Mine Drainage at Shoup’s Run Introduction Acid mine drainage (AMD) is an industrial waste which is the result of the extraction process of the mineral coal from the ground. It causes widespread pollution in the streams above and below the coals fields.

For example, metal at the historic Kennecott Copper Mine in Alaska was found in conjunction with large amounts of carbonate that neutralized any acid-forming compounds. Acid mine drainage is often encouraged by a biological feedback loop.

Once acid mine drainage starts, certain microbes thrive in the acidic environment. These microbes increase the production of sulfuric acid from the surrounding rock, further poisoning the downstream environment for other organisms.

This feedback loop is an important component in all the most severe cases of acid mine drainage. Acid Rock Drainage Natural weathering of sulfide rocks feeds acid and iron into this spring.

Environmental Impacts The increased acidity caused by acid mine drainage has a range of negative effects depending on the severity of the pH change.Increasing the amount of Hydrochloric Acid by various means (oral, topical, intravenous and intramuscular) had been used very successfully in the ’s and ’s for a variety of lymph stasis diseases including infection, tissue degeneration and cancer.

The Problem and the Cleanup Acid mine drainage is a global problem. In the eastern United States alone, AMD from coal mines has adversely impacted fisheries associated with over 13, kilometers (8, miles) of streams in .

Sep 01,  · SIDEBARS. ACID REFLUX AND ASTHMA. Interestingly, percent of non-smokers who have a chronic cough and 60 percent of those who have asthma also have acid reflux.5 Asthma in children and adults is increasing at exponential rates.

Summary. Acid mine drainage (AMD) refers to the outflow of acidic water from a mining site. In most cases, this acid comes primarily from oxidation of iron sulfide (FeS2, also known as pyrite or "fool's gold"), which is often found in conjunction with valuable metals.

Acid mine drainage is a major problem with many hardrock mines, including almost . Potentially acid sulfate soils (also called cat-clays) are often not cultivated or, if they are, planted with rice, so that the soil can be kept wet preventing attheheels.comface drainage of these soils is normally not advisable..

When cultivated, acid sulfate soils cannot be kept wet continuously because of climatic dry spells and shortages of irrigation water, surface drainage .

Urban runoff is a major cause of urban flooding, the inundation of land or property in a built-up environment caused by rainfall overwhelming the capacity of drainage systems, such as storm sewers.

Triggered by events such as flash flooding, storm surges, overbank flooding, or snow melt, urban flooding is characterized by its repetitive, costly and .

Acid Drainage | INAP