According to a survey completed by the Colorado Geological Survey between 1991 and 1999, the number of abandoned mines in Colorado is 18,382. [1] The Arkansas Headwaters, Las Animas River, Rio Grande Headwaters, Alamosa, and Uncompahgre were the priority watersheds studied in this survey. [1] In the survey, analysis was completed with Environmental Degradation Measures ranging from none to extreme. Results showed 26 abandoned mines with extreme degradation and mineral hazards, 219 with significant degradation, and 672 potentially significant hazards. [1]
In recent years, abandoned mine drainage has led to major environmental events, such as the 2015 Gold King Mine waste water spill..
Colorado has ten mines with active water treatment. There are 4.7 billion gallons of polluted water produced per year between these ten mines. Of them, two are abandoned, seven are closed, and one is active. The one active mine, Climax, will produce 2.9 billion gallons of polluted water at its new site. [2] The abandoned mine at Summitville produced 235 million gallons of polluted water needing treatment in 2012 and is projected to produce even more in 2016 at 380 million gallons. The second site in the Earthworks report is the Captain Jack mine, which produces 26 million gallons of polluted water per year. [2]
Acid mine drainage results when surface and ground water combine with sulfuric rock from the mines, causing a sulfuric acid. The sulfuric acid causes leaching of iron, manganese, lead, copper, zinc and cadmium from the rock it interacts with. [3] Acid mine drainage is caused by both abandoned mines and mines in current excavation. Acid mine drainage (AMD) is responsible for surface water pollution in the mid-Atlantic region, as well. [4] In 2012, a report published by the Colorado Division of Reclamation Mining and Safety (DRMS) described the abandoned mine land (AML) areas with greatest need for remediation. Most of these sites no longer have an entity accountable for the costs associated with remediation. [5]
Streams and other water sources are affected by drainage from AML, estimated at as many as 89% of Colorado streams. [5] The South Platte watershed and river basin project is estimated to cost more than two million dollars in characterization, engineering, and reclamation. [5] The areas being addressed in this project to reduce the water contamination include:
Acid mine drainage causes many environmental concerns, one of which is the effects on wildlife, fish and surrounding vegetation. [6] Lead, cadmium, and arsenic are some of the major concerns and detrimental to the ecosystem downstream of the mine drainage. Treatment of acid mine drainage is listed as one of the state's Top 10 winnable battles in gaining clean water. The Colorado Department of Public Health and Environment treats nearly 98 million gallons of water a year from 5 mining sites alone. [6]
The Argo Tunnel was completed in 1910 for the purpose of mining gold during the Colorado Gold Rush. The Argo Tunnel served all major gold mines in Idaho Springs at the time. [7] The main purpose of the tunnel was for transporting ore out of tunnel and onto trains. Argo Tunnel ceased production after a mining disaster in 1943, in which 4 miners died because of a large volume of naturally impounded water flooding the area they were in. [8] The site has been a tourist attraction since the 1970s. [9] Drainage from the Argo Tunnel flows into the Clear Creek River, which is part of a watershed affecting more than one-quarter million people who live in the Denver area. Since the opening of the Argo Tunnel in the early 1900s, there has been discharge of acidic water with high concentrations of heavy metals flowing into the Clear Creek River. [6] The Argo Tunnel discharges water with a pH between 2 and 3, which is below both water quality and drinking water standards. [8] On average, about 850 pounds of dissolved metals are released from the tunnel each day. [6] Because of the high volume of acidic and metallic water flowing into a major water source for parts of the Denver area, many projects have been created to eliminate this issue. One project was the Argo Tunnel Water Treatment Facility, which focused on decreasing and eliminating the acidity and high levels of metal in the water. The plant began treating water in April 1998 and recently was upgraded from a low-density lime precipitation process to a high-density sludge process in June 2013. [6]
Summitville Mine opened in the 1870s, mining gold and silver. During the 1980s, the company, Summitville Consolidated Mining Company, started open-pit mining of gold ore. Open-pit mining uses cyanide, which is poured over the broken-down ore and dissolves the gold. After this process, gold is extracted from the bottom and processed. [10] Environmental problems followed after the beginning of open-pit mining, as acidic and metal-rich water drained into the Alamosa River. Drainage from open-pit mining often has a pH below 3 and high to extreme concentrations of metals. This new process of mining also exposed large volumes of previously oxidized sulfides that affected groundwater. [11] Since the Summitville Mine runs next to the Alamosa River, this drainage affected livestock, agricultural irrigation and wildlife habitat. It is believed that this drainage also explains the 1990 disappearance of stocked fish from the Terrace Reservoir and some farm hold ponds along the river. [11] In the early 1990s the state took over Summitville Mines with help from the EPA. Plans were created to clean up the area and mitigate the environmental damage.
The following is a time line of this major operation:
1994-1995 | Heap Leach Pad detoxification. [10] |
1996 | Cropsy Waste Pile, Beaver Mud Dump, Summitville Dam Impoundment and mine pit closure. [10] |
1996-2000 | Modification to the existing water treatment plant [10] |
1998 | Heap Leach Pad cap complete. [10] |
1998 | Completion of Heap Leach Pad, North Waste Dump. [10] |
2002 | Complete site wide reclamation. [10] |
2004 | Complete water treatment plant design. [10] |
2004-2005 | Complete contaminant source collection structures. [10] |
2008-2009 | Wightman Fork and Summitville Dam Impoundment improvement, installation of micro-hydro-power. [10] |
2010 | Begin construction of new water treatment plant. [10] |
2011 | Completed construction of new water treatment plant. [10] |
2013 | Completed reconstruction of the Wightman Fork rundown structure; Summitville Mine site achieved the site-wide construction completion milestone. [10] |
Discovered in 1887 by Olaf Nelson for the purpose of mining the abundant gold in the city of Silverton, Colorado, the Gold King mine has had many owner throughout its existing. [12] Gold King Mine was shut down in 1923, but subsequent operations continued until as recently as 1991. [13] The Gold King Mine has been in the clean-up process since operations stopped. A blockage in one of the emptying pipes created a build up of pressure and acidic water over time. When it came to remove the blockage and continue with the cleanup process, the EPA and DRMS teams agreed on how to resolve the issue and continued with the clean up. Shortly after they started, pressure overwhelmed the blockage and the water began flowing downstream into the San Juan River and Animas River. The high volume of acidic and metal-laden water quickly turned the Animas River toxic, with a bright orange appearance. Residents were advised to have their water tested, to keep domestic animals away from the rivers, and not to fish or swim in the river. [14]
A timeline shows the clean-up process from start to end:
Wednesday, August 5, 2015 | EPA sends a team to look over the Gold King Mine in Silverton. Upon arrival, they noticed the pipe that drains the mine is plugged. They discuss how to unplug it, but underestimated the water and pressure that had accumulated behind the blockage. The blowout caused an overwhelming amount of acidic water to flow into Cement Creek, which then drains into the Animas river. [13] |
Thursday, August 6, 2015 | EPA announces their team caused blowout. The wastewater reaches Durango by evening. La Plata County Sheriff closes the Animas River. Groups from New Mexico, Arizona, Utah and the Navajo Nation outline an estimate for when the wastewater will hit their lands. [13] |
Friday, August 7, 2015 | EPA starts to clean up and rebuild the settlement ponds at the entrance of the mine. They also start advance testing on the river and conduct aerial flights to view the extended of the spill and clean up. [13] |
Saturday, August 8, 2015 | Colorado Parks and Wildlife have caught and placed fingerling trout in baskets along the river to help save this species from being affected by the wastewater. The wastewater flow is down to 550 gallons per minutes compared to 740 gallons per minute on Friday. Wastewater has reached New Mexico. Aztec and San Juan both shut down their water intakes. [13] |
Sunday August 9 | EPA revises the estimate of the total amount of wastewater spilled from 1 million gallons to 3 million gallons. Aircraft flying over Farmington and Durango say that the wastewater is dissipating as it flows down the San Juan. [13] |
Monday, August 10, 2015 | Colorado Gov. John Hickenlooper makes an announcement about the wastewater flowing from the Gold King Mine, and announces future efforts to focus on other abandoned mines throughout Colorado to prevent a similar disaster. [13] |
Tuesday, August 11, 2015 | John Hickenlooper arrives in Durango and discussions begin with the EPA concerning when the river will be safe to open again. |
August 17 | EPA administrator, Gina McCarthy, reports no one has experienced adverse health effects as a result of the wastewater blowout. [13] |
Wednesday, August 12, 2015 | Durango begins testing the water in the Animas River. [13] |
Thursday, August 13, 2015 | EPA states the water from the Animas River around Durango is back to similar levels of acidity and metal content as before the wastewater blowout. [13] |
Friday, August 14, 2015 | The Animas River reopens to boaters. CDPHE states the water is back to levels that won't affect human health during typical recreation. New Mexico lifts ban on use of private wells stemming from the Animas River Valley. [13] |
The containment and ultimate clean-up of abandoned mines is a challenging problem, as interested parties comprise federal, state, and local governments, property owners, non-profit environmental organizations, and others. Many of the mines were abandoned when regulations did not exist concerning the rehabilitation of the mine’s land. Another complicating facet of acid mine drainage from abandoned mines is the downstream impacts, which affect myriad stakeholders. In terms of the actual locations of abandoned mines in Colorado, most are located on federally managed land, either the Department of Interior’s Bureau of Land Management (BLM) or the United States Department of Agriculture’s National Forest Service (NFS). Approximately 19,000 are located on NFS land [15] with an additional 3,400 abandoned mines on BLM land. [16] Several existing federal programs can be tapped for funding the remediation of abandoned mines including the Surface Mining Control and Reclamation Act of 1977 (SMCRA), the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) which provides money for sites designated Superfunds, and the Clean Water Act Grant Program. [17] There is no single party responsible for the remediation of abandoned mines. Efforts have historically been funded by a combination of these available sources and coordinated by multiple agencies. One example is the Animas River Stakeholders Group, or ARSG, which comprises government agencies, citizen groups, and private entities – mostly mining corporations. This collaboration was dubbed a “pilot success” in a joint BLM and NFS report [17] published in 2007. The subsequent Gold King Mine disaster in this very watershed illustrates the shortcomings of even the most organized efforts to mitigate environmental effects of abandoned mines.
The Gold King Mine disaster brought the importance and danger of abandoned mines back into the public eye. Policy makers sought to formalize a process to identify, prioritize, and fund the reclamation of abandoned mines via the Hardrock Mining Reform and Reclamation Act of 2015 (HMRRA). This law would have created a fund specifically for the reclamation of abandoned mines and a new reclamation fee to be collected from current and future mining activities. The HMRRA never made it out of committee in either the House of Representatives’ Subcommittee on Energy and Mineral Resources [18] or the Senate’s Committee on Energy and Natural Resources. [19] In 2016, the Colorado Department of Public Health and the Environment (CDPHE) organized a $300,000 project, in conjunction with the Colorado Geological Survey, to inventory Colorado’s abandoned mines and prioritize each site’s reclamation according to current or potential environmental and human health impacts. While the intent of this project is merely to inventory the abandoned mines, the report will be a valuable asset if and when more funds become available for remediation. [20]
The Summitville mine was a gold mining site in the United States, located in Rio Grande County, Colorado 25 miles (40 km) south of Del Norte. It is remembered for the environmental damage caused in the 1980s by the leakage of mining by-products into local waterways and then the Alamosa River.
Land rehabilitation as a part of environmental remediation is the process of returning the land in a given area to some degree of its former state, after some process has resulted in its damage. Many projects and developments will result in the land becoming degraded, for example mining, farming and forestry. It is crucial that governments and businesses act proactively by working on improvement, lay out rehabilitation standards and ensure that decisions on mediation should be based around value judgment for higher sustainability in the future.
The General Mining Act of 1872 is a United States federal law that authorizes and governs prospecting and mining for economic minerals, such as gold, platinum, and silver, on federal public lands. This law, approved on May 10, 1872, codified the informal system of acquiring and protecting mining claims on public land, formed by prospectors in California and Nevada from the late 1840s through the 1860s, such as during the California Gold Rush. All citizens of the United States of America 18 years or older have the right under the 1872 mining law to locate a lode or placer (gravel) mining claim on federal lands open to mineral entry. These claims may be located once a discovery of a locatable mineral is made. Locatable minerals include but are not limited to platinum, gold, silver, copper, lead, zinc, uranium and tungsten.
Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines and coal mines.
Gold mining in Colorado, a state of the United States, has been an industry since 1858. It also played a key role in the establishment of the state of Colorado.
An abandoned mine refers to a former mining or quarrying operation that is no longer in use and has no responsible entity to finance the cost of remediation and/or restoration of the mine feature or site. Such mines are typically left unattended and may pose safety hazards or cause environmental damage without proper maintenance. The term incorporates all types of old mines, including underground shaft mines and drift mines, and surface mines, including quarries and placer mining. Typically, the cost of addressing the mine's hazards is borne by the public/taxpayers/the government.
The Leadville mining district, located in the Colorado Mineral Belt, was the most productive silver-mining district in the state of Colorado and hosts one of the largest lead-zinc-silver deposits in the world. Oro City, an early Colorado gold placer mining town located about a mile east of Leadville in California Gulch, was the location to one of the richest placer gold strikes in Colorado, with estimated gold production of 120,000–150,000 ozt, worth $2.5 to $3 million at the then-price of $20.67 per troy ounce.
Spring Creek Debris Dam is an earthfill dam on Spring Creek, a tributary of the Sacramento River, in Shasta County in the U.S. state of California. Completed in 1963, the dam, maintained by the U.S. Bureau of Reclamation, serves primarily to collect severe acid mine drainage stemming from the Iron Mountain Mine. The dam forms the Spring Creek Reservoir, less than 1 mile (1.6 km) long. Spring Creek and South Fork Spring Creek flow into the reservoir from a 16-square-mile (41 km2) watershed. The dam is directly upstream from the city of Keswick, California and the Keswick Reservoir. The operation is part of the Trinity River Division of the Central Valley Project.
The Argo Tunnel is a 4.16-mile (6.69 km) mine drainage and access tunnel with its portal at Idaho Springs, Colorado, USA. It was originally called the Newhouse Tunnel after its primary investor, Salt Lake City mining magnate Samuel Newhouse, and appears by that name in many industry publications from the time period when it was constructed. The tunnel intersected nearly all the major gold mines between Idaho Springs and Central City, and is the longest such drainage tunnel in the Central City-Idaho Springs mining district.
Environmental impact of mining can occur at local, regional, and global scales through direct and indirect mining practices. Mining can cause erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These processes also affect the atmosphere through carbon emissions which contributes to climate change.
Leviathan Mine is a United States superfund site at an abandoned open-pit sulfur mine located in Alpine County, California. The mine is located on the eastern slope of the Sierra Nevada at about 7,000-foot (2,100 m) elevation, 6 miles (9.7 km) east of Markleeville and 24 miles (39 km) southeast of Lake Tahoe. The mine site comprises approximately 250 acres (100 ha) of land surrounded by the Toiyabe National Forest, which is only accessible a few months a year. The approximately 22 million tons of sulfur ore-containing crushed rock at the mine are responsible for contaminating the Leviathan and Aspen Creek, which join with Mountaineer Creek to form Bryant Creek which ultimately empties into the East Fork of the Carson River. These water bodies are listed as 303(d) impaired. The site location is seismically active.
Coal mining in Brazil is an important part of the country's energy economy as its largest source of non-renewable energy. Brazil is the tenth largest energy consumer in the world and the third largest in the Western Hemisphere. Coal accounts for approximately 5.8 percent of the country's total primary energy supply. It is the country's largest source of non-renewable energy, followed by nuclear energy, petroleum, and natural gas. Brazil produces about 6 million tons of coal per year, and total coal reserves are estimated at approximately 32.3 billion tons. It is also important in reducing reliance on imported oil and gas.
The Jeddo Tunnel is a drainage tunnel at water level in Pennsylvania. It is one of the Coal Region's biggest discharges of mine water. The tunnel is five miles long and was constructed between 1891 and 1894, and at the time of its construction, was reputed to be the largest mine drainage tunnel in the world. It consists of major tunnels A and B, and minor tunnels C, D and X.
The Oneida Number One Tunnel is a mine drainage tunnel in Schuylkill County, Pennsylvania, in the United States. It is one of five major mine tunnels in the watershed of Catawissa Creek. The tunnel discharges into Sugarloaf Creek near Lake Choctaw and Lake Susquehanna. The water quality of the tunnel's discharge has improved significantly since the installation of a treatment system at the site of the tunnel in 2001.
The Green Mountain Tunnel is a mine drainage tunnel in Schuylkill County, Pennsylvania, in the United States. It is one of five major mine drainage tunnels in the watershed of Catawissa Creek. The tunnel discharges into Catawissa Creek near the Audenried Tunnel and the Catawissa Tunnel. The tunnel was constructed in the 1930s and is slightly less than one mile long.
The Quakake Tunnel is a mine drainage tunnel in Carbon County, Pennsylvania, in the United States. The tunnel is several thousand feet long and has a discharge of thousands of gallons per minute. It was the subject of an Operation Scarlift report. The tunnel is a major contributor of acid mine drainage to the watershed of the Lehigh River.
Cranberry Creek is a tributary of Stony Creek in Luzerne County, Pennsylvania, in the United States. It is approximately 4.4 miles (7.1 km) long and flows through Hazle Township. The creek is affected by acid mine drainage. It also contains metals such as iron, manganese, and aluminum. It is in the drainage basin of the Jeddo Tunnel. Major roads in the creek's watershed include Pennsylvania Route 924, Pennsylvania Route 309, and Interstate 81. At least one bridge has been built over it. The creek has undergone restoration and there are plans to construct an area known as the Cranberry Creek Gateway Park in its vicinity.
Operation Scarlift was a program carried out by the Pennsylvania government in the 1960s and 1970s. Its mission was to repair environmental damage caused by abandoned mine lands, acid mine drainage, and other issues associated with historic mining. The operation began around the time that the Land and Water Conservation and Reclamation Act was passed and became inactive in the 1970s due to a lack of funding. During the operation, a total of $141,000,000 was spent on a variety of tasks, including remedying pollution in hundreds of streams, extinguishing dozens of mine fires, and constructing acid mine drainage treatment plants. Numerous reports on mining-impacted streams were produced during the operation, many of which continue to be used for assessing watersheds.
The 2015 Gold King Mine waste water spill was an environmental disaster that began at the Gold King Mine near Silverton, Colorado, when Environmental Protection Agency (EPA) personnel, along with workers for Environmental Restoration LLC, caused the release of toxic waste water into the Animas River watershed. They caused the accident by breaching a tailings dam while attempting to drain ponded water near the entrance of the mine on August 5. After the spill, the Silverton Board of Trustees and the San Juan County Commission approved a joint resolution seeking Superfund money.
Abandoned mine drainage is a form of water pollution involving water that has been polluted by contact with mines, typically coal mines. Although it is sometimes called "acid mine drainage", not all abandoned mine drainage is acidic.