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Mining and Water Quality
USGS Mine Drainage Activities
This archived website contains past mining-related projects, activities, and publications.
This archived website contains past mining-related projects, activities, and publications.
Water-Quality Data for the Nation
The USGS National Water Information System (NWIS) contains extensive water-quality data for thousands of sites nationwide.
The USGS National Water Information System (NWIS) contains extensive water-quality data for thousands of sites nationwide.
Water Quality Information by Topic
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Mine drainage is metal-rich water formed from a chemical reaction between water and rocks containing sulfur-bearing minerals. Problems that can be associated with mine drainage include contaminated drinking water, disrupted growth and reproduction of aquatic plants and animals, and the corroding effects of the acid on parts of infrastructures such as bridges.
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Mining and Water Quality
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Mine drainage is metal-rich water formed from a chemical reaction between water and rocks containing sulfur-bearing 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 the red, orange, or yellow sediments in the bottom of streams containing mine drainage. The acid runoff further dissolves heavy metals such as copper, lead, mercury into groundwater or surface water. The rate and degree by which acid-mine drainage proceeds can be increased by the action of certain bacteria.
Acidic, metal-laden drainage from abandoned coal mines can have substantial effects on aquatic resources. Problems that can be associated with mine drainage include
- contaminated drinking water
- disrupted growth and reproduction of aquatic plants and animals
- the corroding effects of the acid on parts of infrastructures such as bridges
As with any environmental damage, there are costs associated with trying to come up with a solution to the problem. In the Appalachian region of West Virginia, for example, the cost of correcting acidic mine drainage-related problems with currently available technology is estimated at $5-$15 billion.
Sources/Usage: Public Domain. View Media Details
The world's most acidic water is found in a mine
Sources/Usage: Public Domain. View Media Details
Credit: C. Alpers and D.K. Nordstrom, USGS
In a U.S. Geological Survey (USGS) study, the most acidic waters ever measured are percolating through an underground mine near Redding, Calif. Hot acid solutions, more concentrated than battery acid, are dripping off colorful mineral stalactites in the abandoned copper and zinc mine at Iron Mountain, a northern California "Superfund" site that is undergoing remediation by the US Environmental Protection Agency (EPA). Although a water-treatment plant at Iron Mountain has reduced the amount of copper and zinc leaching from Iron Mountain by 80 to 90 percent since 1994, some acid waters from the mine site still make their way to Spring Creek, a tributary to the Sacramento River, a few miles upstream from Redding.
pH values are reported as being in a range of 0 to 14, with 7 being neutral. Values of pH near 0 are highly acidic, becoming less acidic and more alkaline at the higher numbers. Because pH is measured on a logarithmic scale, each declining unit represents 10 times more acidity. USGS scientists said several of the drip-water samples at Iron Mountain had pH values below zero, indicating hydrogen ion activities greater than one. The lowest pH found at California mine site was -3.6.
View the USGS California Water Science Center page on this topic.
More information:
- Estimated Use of Water in the United States in 2000, USGS Circular 1268 (see chapter on Mining Use)
Sources/Usage: Public Domain. View Media Details
Want to know more about mining and water quality? Follow me to the Mine Drainage website!
Below are multimedia items associated with mining and water quality.
Below are frequently asked questions associated with mining and water quality.
How does mine drainage occur?
Mine drainage is surface water or groundwater that drains from an active or abandoned mine. In some cases, pyrite (an iron sulfide mineral) is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Some or all of this iron can precipitate to form the red, orange, or yellow sediments in the bottom of streams containing mine drainage. The acid runoff further dissolves heavy...
Can lakes near volcanoes become acidic enough to be dangerous to people and animals?
Yes. Crater lakes atop volcanoes are typically the most acid, with pH values as low as 0.1 (very strong acid). Normal lake waters, in contrast, have relatively neutral pH values near 7.0. The crater lake at El Chichon volcano in Mexico had a pH of 0.5 in 1983 and Mount Pinatubo's crater lake had a pH of 1.9 in 1992. The acid waters of these lakes are capable of causing burns to human skin but are...
How do we extract minerals?
The primary methods used to extract minerals from the ground are: Underground mining Surface (open pit) mining Placer mining The location and shape of the deposit, strength of the rock, ore grade, mining costs, and current market price of the commodity are some of the determining factors for selecting which mining method to use. Higher-grade metallic ores found in veins deep under the Earth’s...
Mine drainage is metal-rich water formed from a chemical reaction between water and rocks containing sulfur-bearing minerals. Problems that can be associated with mine drainage include contaminated drinking water, disrupted growth and reproduction of aquatic plants and animals, and the corroding effects of the acid on parts of infrastructures such as bridges.
• Water Science School HOME • Water Quality topics •
Mining and Water Quality
Sources/Usage: Public Domain. View Media Details
Mine drainage is metal-rich water formed from a chemical reaction between water and rocks containing sulfur-bearing 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 the red, orange, or yellow sediments in the bottom of streams containing mine drainage. The acid runoff further dissolves heavy metals such as copper, lead, mercury into groundwater or surface water. The rate and degree by which acid-mine drainage proceeds can be increased by the action of certain bacteria.
Acidic, metal-laden drainage from abandoned coal mines can have substantial effects on aquatic resources. Problems that can be associated with mine drainage include
- contaminated drinking water
- disrupted growth and reproduction of aquatic plants and animals
- the corroding effects of the acid on parts of infrastructures such as bridges
As with any environmental damage, there are costs associated with trying to come up with a solution to the problem. In the Appalachian region of West Virginia, for example, the cost of correcting acidic mine drainage-related problems with currently available technology is estimated at $5-$15 billion.
Sources/Usage: Public Domain. View Media Details
The world's most acidic water is found in a mine
Sources/Usage: Public Domain. View Media Details
Credit: C. Alpers and D.K. Nordstrom, USGS
In a U.S. Geological Survey (USGS) study, the most acidic waters ever measured are percolating through an underground mine near Redding, Calif. Hot acid solutions, more concentrated than battery acid, are dripping off colorful mineral stalactites in the abandoned copper and zinc mine at Iron Mountain, a northern California "Superfund" site that is undergoing remediation by the US Environmental Protection Agency (EPA). Although a water-treatment plant at Iron Mountain has reduced the amount of copper and zinc leaching from Iron Mountain by 80 to 90 percent since 1994, some acid waters from the mine site still make their way to Spring Creek, a tributary to the Sacramento River, a few miles upstream from Redding.
pH values are reported as being in a range of 0 to 14, with 7 being neutral. Values of pH near 0 are highly acidic, becoming less acidic and more alkaline at the higher numbers. Because pH is measured on a logarithmic scale, each declining unit represents 10 times more acidity. USGS scientists said several of the drip-water samples at Iron Mountain had pH values below zero, indicating hydrogen ion activities greater than one. The lowest pH found at California mine site was -3.6.
View the USGS California Water Science Center page on this topic.
More information:
- Estimated Use of Water in the United States in 2000, USGS Circular 1268 (see chapter on Mining Use)
Sources/Usage: Public Domain. View Media Details
Want to know more about mining and water quality? Follow me to the Mine Drainage website!
Below are multimedia items associated with mining and water quality.
What is mine drainage and how does it occur?
Listen to hear the answer.
Below are frequently asked questions associated with mining and water quality.
How does mine drainage occur?
Mine drainage is surface water or groundwater that drains from an active or abandoned mine. In some cases, pyrite (an iron sulfide mineral) is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Some or all of this iron can precipitate to form the red, orange, or yellow sediments in the bottom of streams containing mine drainage. The acid runoff further dissolves heavy...
Can lakes near volcanoes become acidic enough to be dangerous to people and animals?
Yes. Crater lakes atop volcanoes are typically the most acid, with pH values as low as 0.1 (very strong acid). Normal lake waters, in contrast, have relatively neutral pH values near 7.0. The crater lake at El Chichon volcano in Mexico had a pH of 0.5 in 1983 and Mount Pinatubo's crater lake had a pH of 1.9 in 1992. The acid waters of these lakes are capable of causing burns to human skin but are...
How do we extract minerals?
The primary methods used to extract minerals from the ground are: Underground mining Surface (open pit) mining Placer mining The location and shape of the deposit, strength of the rock, ore grade, mining costs, and current market price of the commodity are some of the determining factors for selecting which mining method to use. Higher-grade metallic ores found in veins deep under the Earth’s...