10 California Mine Disasters Worse Than August's Spill in Colorado

Acid mine drainage from the New Idria Mercury Mine in San Benito County | Photo: U.S. EPA

On August 5, an Environmental Protection Agency contractor working to clean up the Gold King Mine site in Silverton, Colorado accidentally spilled 3 million gallons of toxic acid mine drainage into the Animas River. The spill turned the river bright orange, killing aquatic life, and causing severe hardship for local Navajo ranchers who depend on the river. It's almost a month later, and the incident has largely faded from the news cycle, but the EPA is still taking official heat for its role in the accident and its subsequent response.

The agency made some mistakes, briefly stonewalling locals about the health hazards. The Navajo, who are still dealing with almost literal fallout from a 1979 uranium mine waste spill into the Rio Puerco, can't be faulted for being livid at EPA over their handling of the Animas disaster. (As we see in this episode of Earth Focus, the West's rivers don't need any more problems.) But make no mistake: the EPA may have stumbled, but it didn't cause the problem at Gold King Mine. The agency has the unenviable task of cleaning up after one of the planet's most polluting industries. In the American West, federal law allows mining companies to extract precious metals and valuable minerals from public land nearly for free, and doesn't hold them responsible for cleaning up their messes. That job is left to the EPA to clean up on the taxpayers' dime.

And in case you thought the Animas River spill was out of the ordinary, we found ten mines in California that may well be worse. Some of them have been leaking into our waterways for decades, endangering wildlife and our public health. Some are historic, others ongoing. And the EPA and other agencies have been left holding the bag to clean them up.

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California was founded on mining, so the industry's legacy here is older than the state. Legal wrangling over mineral rights on public land in California and other western states shaped law nationwide in the 19th Century. First came the so-called "Chaffee Law" of 1866, which gave private miners easy ownership of claims on hardrock ore outcrops on public land. The Chaffee law covered gold, silver, copper, and the mercury ore known as cinnabar -- which last, as we shall see, left a huge legacy of damage to California waterways. A similar law in 1970 covered placer mining, or mining of minerals eroded into gravel deposits.

The General Mining Act of 1872, signed by President Ulysses. S Grant, expanded the previous two laws to cover other kinds of mining. It granted private companies the right to extract minerals from public lands without paying a royalty, and set maximum prices of $2.50- $5.00 per acre of land in each mining claim. Those prices have not been raised since.

Most importantly for our purposes here, the General Mining Act of 1872 makes no provision for cleanup or restoration of mining sites. That's not surprising: ecology was a novel concept in 1872 and wouldn't gain acceptance for another century.

Subsequent attempts to update and modernize the 1872 mining law have generally failed. Some progress was made in 1976 when Congress passed the Federal Lands Policy Management Act (FLPMA), which covers mines on lands managed by the Bureau of Land Management. On BLM lands, large mine operators must now conduct environmental assessments and put money in a reclamation bond.

And if the EPA designates a mine as a Superfund site, which is the case for all but one of the mines we've listed here, they can determine that a mining company or other party is wholly or partly responsible for the mess, and try to get that company to pay for at least part of the cleanup. That's a relatively arduous process, and it doesn't really work when the mining company has gone out of business.

Despite those and a few other mild reforms, public lands mining is governed by a federal law that was written to encourage all mining at all costs, as part of an attempt to spur increased settlement of the western states. It's as if the main federal laws regulating the internet were written in the first days of the telegraph.

In fact, hardrock mines enjoy the benefits of a specific loophole in the Clean Water Act that allows them to designate a watershed as a "waste treatment system," thus escaping the Act's prohibition of point source pollution of our nation's waterways. The EPA has also allowed mining companies to designate acidic and toxic metal-ridden mine wastes as "fill material," thus sidestepping regulation under the Clean Water Act.

The 1872 Mining Law also doesn't even require that pollution from mines be monitored. Which means that all of these California mines may well have done many times more damage to California's waterways over the last century and a half than the spill in Silverton did in August, but the precise figures for just how much each mine polluted California we may never know.

This isn't a complete list: there are hundreds of leaking mines in California that need attention. These are just some of the worst.

Jamestown Mine and Harvard Pit

Arsenic-laden water in the Jamestown Mine's Harvard Pit | Photo: California State Mines and Geology Board

A gold mine that operated for two decades, the Jamestown Mine near the Tuolumne County hamlet of Chinese Camp is already thought to have contributed a significant amount of arsenic to Woods Creek, a tributary of the Tuolumne River. The largest of the mine's three open pits, the Harvard Pit, has been filling with local groundwater since the mine closed in 1994. Once the water level in the Harvard Pit reaches 1,330 feet above sea level, that water will begin leaching through local bedrock and into Woods Creek. That's a problem: the water in the pit has a whole lot of arsenic in it, along with sulfates and nitrates. Once that tainted water hits Woods Creek, it's a straight shot to the Tuolumne by way of the Don Pedro Reservoir, where water is stored for use in irrigation and urban tap water in the Modesto Area.

Without intervention by the mine owners, the Harvard Pit was expected to reach that critical water level in December of this year. But under orders of the California Regional Water Quality Control Board, the mine owners have been trying to keep the water level lower by pumping 300 gallons of the water through misters per minute , which allows about of the pit's water to evaporate. Of course as the water evaporates, the concentration of arsenic and other contaminants in the put water increases.

A 2014 news story on a local TV station revealed that the mine's owners have another method in mind: cleaning the water up and selling it to drought-ravaged Californians. Regardless of the means by which the water's taken from the Harvard Pit, it's a big task: about 55 million gallons of the contaminated water will need to be removed safely each year starting in 2018. Aside from the threat to the Tuolumne and the San Joaquin River and SF Bay Delta into which it flows, hundreds of drinking water wells are just downhill of the Harvard Pit.

Lava Cap Mine

This Gold Rush era mine a short distance from Nevada City and Grass Valley started operation in 1861. Aside from a 16-year gap immediately following World War I, the mine was in more or less continuous operation until 1943. Thousands of people now live within five miles of the semi-rural site, which, like the remainder of the mines in our list, has been deemed a Superfund site by the Environmental Protection Agency.

The reason is that the Lava Cap Mine left a hole lot of arsenic in nearby ground and surface water, to the point where the EPA had to built a municipal water system for those homes closest to the mine site. Arsenic in nearby Little Clipper Creek and Lost Lake have tested well above the EPA's allowable levels for drinking water, and the agency recommends neighbors clean their shoes and hose down their pets after walking near the ubiquitous mine tailings piles.

Those arsenic-laden mine tailings became the source of pointed concern in January 1997, when huge El Niño winter storms collapsed the upper section of a 60-foot log dam the mine's owners had built half a century earlier. The dam was intended to contain mine tailings that had been treated with cyanide and dumped into a local ravine. When the dam broke in 1997 10,000 cubic yards of those toxic tailings -- about two million gallons -- flowed into Little Clipper Creek, submerging local wetlands inhabited by western pond turtles and foothill yellow-legged frogs. But that was just thew worst single day for the local watershed: Lava Cap Mine had been dumping its tailings in the creek for decades during the 19th and early 20th centuries.

Legal wrangling over who pays the cleanup bill at Lava Cap is ongoing, with a trial set for mid-2016. The EPA and the California Department of Toxic Substances Control say the tab will run in excess of $50 million.

Leviathan Mine

The Leviathan Mine. Note orange mine drainage in holding ponds | Photo: Uncle Kick-Kick/Flickr/Creative Commons License

California's least populated county is home to one of the state's most polluting abandoned mines. Tiny Alpine County, whose largest town Markleeville boasted 210 residents during the 2010 Census, is where the Atlantic Richfield Company operated the Leviathan open-pit sulfur mine from 1952-1962, 25 miles southeast of Lake Tahoe.

The legacy of that mine's operation was stark. From the mine's closing in 1962 until the early part of this century, rainwater and snowmelt reacted with the sulfur in the mine walls and tailings to create what's known as acid mine drainage, a highly acidic form of water pollution that's incredibly hard on aquatic life. The mine's drainage flowed into nearby flowing into Leviathan and Bryant creeks, which the EPA describes as "devoid of insects and fish" for nine miles downstream. That's where the creeks' waters end up in the east fork of the Carson River, a drinking water source for a number of communities on the East Side of the Tahoe Sierra.

Acid mine drainage doesn't just pose a problem due to its extremely low pH. The more acidic water is, the more readily it can dissolve metals that may themselves be toxic. According to the EPA, the Leviathan Mine's drainage may have contained about a sixth of the elements in the Periodic Table, with specified contaminants of concern including aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, hexavalent chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, selenium, silver, thallium, vanadium, and zinc.

The state of California owns the land now, and EPA and the state have been working with Atlantic Richfield to assess and repair some of the damage. In 2000, treatment facilities were built on site to reduce the amount of acid mine drainage reaching the creeks; each year those facilities treat about 17 million gallons of mine drainage, or about two-thirds of the total. the water's gotten a bit cleaner and aquatic insects have started to return.

But there's still a lot of work to do, and EPA expects to have a remediation feasibility study finished next year. In the meantime, reduced levels of metal-contaminated acid mine drainage are still working their way into the Carson River, where they may heighten the pollution load for residents of Carson City and Fallon, Nevada, as well as in the Stillwater National Wildlife Refuge at the bottom of the river.

Atlas Asbestos Mine and Coalinga Asbestos Mine

These two asbestos mines are close enough that it's best to discuss them as a single facility. Covering about 550 acres near the Central Valley town of Coalinga, the two mines operated from the early 1960s until the late 1970s, when some of the health hazards associated with asbestos exposure became better known, and the fireproofing and insulating material started to be considered hazardous waste rather than a useful industrial product.

Mining and processing asbestos releases the hazardous fibers into the air, and those fibers, which can cause the cancer mesothelioma when inhaled, are also present in large amounts in asbestos mine tailings. The city of Coalinga was a center for processing, storing, and transporting asbestos from the two mines: about 107 acres of the city had to be more or less torn down and buried in the early 1990s.

The EPA now considers the two mines, along with the contaminated area in downtown Coalinga, to be cleaned up. But an unusual potential threat to public health came to light during the cleanup when scientists found elevated levels of asbestos in water in the California Aqueduct. The Atlas Mine area drains into Los Gatos Creek, which ends at a floodplain adjacent to the Aqueduct. Sediment from the mines raised the level of that floodplain to the point where floodwaters could leak into the Aqueduct, bringing asbestos fibers and other mine waste contaminants with them.

The EPA says on its official Atlas Asbestos Mine page that "most of the downstream users of the aqueduct water are protected by filtration and settling pond systems, which trap most of the asbestos fibers." The agency also mentions that the California Department of Water Resources expanded the flood containment area at the bottom of Los Gatos Creek in 2004. It's a good reminder that mine waste doesn't just get into natural rivers: our expensive water-conveyance infrastructure can also be at risk.

Gray Eagle Mine

The Klamath River at its confluence with Indian Creek, where contaminants from the Gray Eagle Mine once flowed into the river, and may still | Photo: gapeppy1/Flickr/Creative Commons License

This site near Happy Camp, about seven miles south of the Oregon Line, was once the largest copper mine in California. During the 1940s, Newmont Mining Company extracted about 460,000 tons of high-grade copper ore from this 200-plus acre network of mining claims uphill from the Klamath River. In the 1980s, Noranda Mining leased Gray Eagle and pulled 180,000 ounces of gold from an open pit on the site. (At current values, that's more than $200 million in gold.)

Gray Eagle is still an active mine, or at least it's being actively bought and sold by mining companies, who suspect there's still metal left in them there hills. The site also boasts tons of copper mine tailings left over from the World War Two era, which were moved from the mine via a sluice line and piled up on the banks of Indian Creek, a tributary of the Klamath River.

A post-war lumber mill on Indian Creek Road graded some of those tailings to form a log pond, exposing the tailings to creek water, which caused acid mine drainage to form. The rest of the tailings are exposed to the region's heavy rains, both leaching drainage into the groundwater and occasionally getting swept out into the Klamath River when Indian Creek undercuts the tailings bank.

The result: orange, polluted water rolling down five miles of Indian Creek and into the Klamath River, habitat for endangered coho and steelhead, as well as chinook salmon.

In the late 1990s the U.S. Forest Service moved the tailings into the former log pond, graded the pile, covered it with a polyethylene liner and covered the liner with soil and native plants. Leaching of acid mine drainage has slowed since.

Blue Ledge Mine

Acid tailings from the Blue Ledge mine slowly tumble into Joe Creek at lower left | Photo: U.S. Forest Service

About three miles south of the Oregon line in Siskiyou County, the abandoned Blue Ledge Mine north of Seiad Valley has been leaking toxic metals into the Rogue River watershed for perhaps 85 years.

The copper, gold, silver, and zinc mine on private land in the Rogue River - Siskiyou National Forest, in operation from 1904 to 1930, eventually held more than two miles of shafts and tunnels. Acid mine drainage has been coming from the mine since its closure, and entering nearby Joe Creek, a tributary of the Applegate River.

The EPA reports that there are no fish in Joe Creek due to acid mine drainage. Joe Creek flows into the Applegate by way of Elliott Creek; cadmium, copper, and other toxic metals have been found in sediments in the two creeks and the Applegate River all the way to the Applegate Reservoir, a popular fishing and camping area.

Remediation efforts started in 2006, with the U.S. Forest Service removing enough waste rock in 2010-2011 to fill a cube the height of an eight story building. Some of the waste piles were also covered with soil and revegetated so that people would be less likely to come into contact with the toxic metals. That's a big start, but the mine's adits, or horizontal shafts, are still leaking mine drainage into Joe Creek.

Klau/Buena Vista Mine

Twelve miles west of Paso Robles along the Central Coast, these mercury mines in the Santa Lucia Mountains were in steady operation from the 1860s through 1970. Mercury, which was in great demand during the Gold Rush for use in separating precious metals from their ores, is one of the more toxic metals mined in California, and wastes from both mines were simply dumped in downstream drainage channels for more than a century.

The process of extracting mercury from its ore is heavily polluting as well: mercury sulfide ores are heated in a large vessel called a retort. The sulfides combine with oxygen when heated, forming sulfur dioxide. Liberated from its bond to the sulfides, the mercury vaporizes and is cooled in pipes resembling a giant still.

Unless a mercury extraction facility has bombproof ductwork, that mercury vapor leaks out and condenses onto the surrounding landscape, along with any sulfur dioxide that leaks out of -- or is dumped from -- the facility.

The wastes that remains when the ore is cooked, called "calcines," still contain a significant amount of soluble mercury. When calcines are dumped in the countryside around a mine, rains and other moisture can carry that mercury into ground and surface water, where they react with organic matter to form the highly toxic substance methylmercury.

The 317 acres occupied by the Klau and Buena Vista mines, piled with upwards of 300,000 tons of waste rock and tailings, leak enough mercury into local creeks to violate standards set by both the EPA and the Regional Water Quality Control Board. Acid mine drainage is an issue here as well; drainage from Klau/Buena Vista's underground tunnels contains hazardous amounts of iron, manganese, aluminum, boron, nickel, selenium, thallium, and zinc in addition to mercury.

And that's not just a problem for locals, because the creeks downstream from Klau and Buena Vista flow into Lake Nacimiento, a 377,000-acre-foot reservoir that supplies Monterey and San Luis Obispo counties. Monterey County uses water from the reservoir to recharge aquifers in the Salinas Valley. Lake Nacimiento's methylmercury contamination, high enough that eating most fish from the reservoir is considered dangerous, may well end up getting sprayed onto row crop fields in Soledad and Castroville.

Sulphur Bank Mine

Warning sign at Sulphur Bank | Photo: Marcia Wright/Wikimedia Commons/Creative Commons License

Clear Lake, in Northern California's Lake County, is the largest freshwater lake wholly within the state of California. (Tahoe is larger, but Nevada claims a slice of it.) Despite its size and its scenic surroundings north of the Bay Area, Clear Lake isn't well known elsewhere in California.

Which might be part of how this scenic 68-square-mile lake, home to fish species that live nowhere else on Earth, got saddled with a mercury mine a few hundred feet from its shore.

The Sulphur Bank Mercury Mine opened for business in 1856, initially as a borax mine. Mine operators changed their focus to sulfur in 1865. Mercury ore was discovered onsite in 1860, but extracting the heavy metal wasn't economical until demand from gold and silver miners spiked mercury prices in the 1870s. Underground mining for mercury started at Sulphur Bank in 1873, lasting until 1905. After a 10-year hiatus, the mine reopened as an open-pit mine, closing permanently in 1957. While in operation, Sulphur Bank was one of the largest mercury mines in the state,

During its course of operations the mine's operators dumped more than two million cubic yards of mercury- and arsenic-contaminated tailings and other mine waste. Dumping occurred both on the 150-acre property and in the lake itself, building up banks of tailings along 1,300 feet of shoreline on the lake's east end.

Residents of the adjacent Elem Indian Colony of Pomo Indians, consisting of about 100 people just northwest of the mine, have been exposed to very high levels of mercury and arsenic as a result. Mine wastes underlay a number of residential yards on the rancheria; the wastes were also used by the Bureau of Indian Affairs as roadbed fill when the BIA built gravel and paved roads throughout the settlement in the early 1970s, as well as for the construction pads beneath rancheria homes.

The EPA removed much of the contaminated soil from beneath the rancheria in 2006-7, which involved rebuilding 17 houses and removing and replacing the paved roads. Any remaining mine waste on the rancheria itself was covered with a thick layer of clean imported soil.

That made things a bit better for the Pomo residents of the Elem Colony, though they still contend with the legacy of decades of mercury and arsenic exposure. The lake itself, though, is so full of mercury from the mine that health officials recommend drastically limiting your consumption of fish caught in the lake.

One continuing threat comes from one of the mine's open pits, the Herman Impoundment, now a 23-acre lagoon full of acid mine drainage contaminated with mercury, arsenic, and antimony. The surface of the 90-foot deep impoundment is 750 feet above the lake, and less than 200 feet away from the shore. A rainstorm that filled the impoundment to overflowing could flush a whole lot of toxic water into Clear Lake in a very short time.

EPA has built storm drains in the area to keep rainwater from overflowing the Herman Impoundment, but the mine drainage remains.

New Idria Mercury Mine

Acid mine drainage at New Idria, 2013 | Photo: Joe Nehls/Wikimedia Commons/Creative Commons License

California's oldest mercury mine is spread out over 8,000 acres of highly contaminated land in the inner Coast Ranges east of Pinnacles National Park. Once the second-most productive mercury mine in North America, New Idria produced more than 38 million pounds of the heavy metal from its opening in 1854 until the mine was finally closed in the early 1970s.

The site still has as much as two million tons of waste rock and calcines in a 40-acre area, leaching mercury and other toxic elements into neighboring San Carlos Creek, a tributary of the San Joaquin River. Acid mine drainage is a problem at New Idria, as well: the mine's 30 miles of tunnels, which penetrate the earth down a distance equivalent to 20 stories, have long been flooded. That collected water, acidified by contact with iron and sulfur ores, has been leaking out of an adit on the mine's tenth level for years and then running through the mine's tailings piles, where the discharge dissolves stray mercury, arsenic, and other toxic metals.

Some estimates have it that 21 million gallons of acid mine drainage comes out of New Idria and into local creeks in a typical year. That's the equivalent of one Gold King Mine/Animas River disaster every month and a half.

San Carlos Creek is part of a near-unique ecosystem. San Carlos Creek flows into Silver Creek, which then joins the main stem of Panoche Creek. The Panoche Creek watershed is one of the largest on the east side of the Diablo Range that flows even close to year-round, making the watershed's riparian woodlands and wetlands near-irreplaceable habitat. Thirteen endangered and threatened species use this watershed, including the giant kangaroo rat and the San Joaquin kit fox.

Which makes the mercury contamination that's been leaking from New Idria for a century and a half all the more troubling. Mercury above background levels has been detected at least 20 miles downstream from the mines in both San Carlos and Silver Creeks, and the EPA says the degree of contamination in Panoche Creek is "unknown."

It's safe to assume, given that New Idria had been leaking for decades before the EPA was able to start work on the site, that mercury from the mines has reached the San Joaquin River, and eventually the Delta and San Francisco Bay, during any number of moderately wet winters. That would put that mercury into the drinking water for two thirds of Californians.

In 2011, the EPA rerouted the mine drainage away from the tailings and into an evaporation pool, so as to (in the EPA's words) "allow some of the metals to settle out prior to its discharge into San Carlos Creek."

But as with many of the mines in desperate need of cleanup on this list, the problem remains.

Iron Mountain Mine

Drainage out of Iron Mountain Mine | Photo: U.S. Fish and Wildlife Service

Routinely included in lists of the nation's most polluted industrial sites, the Iron Mountain Mine near Redding, also known as the Richmond Mine, is the site of some of the most concentrated acid mine drainage on the planet. The liquid oozing out of Iron Mountain has been measured at a pH of -3.6, more than 6,300 times as acidic as battery acid. Acid mine drainage from Iron Mountain is so potent that when the EPA attempted to stop one of the leaks by experimentally plugging one of the mine's adits, the fluid ate through the thick plug of concrete and steel.

The mine, in operation from the 1860s until 1963, served as a source of iron, silver, gold, copper, zinc, and pyrite. It's also been in the running for California's worst ongoing environmental disaster.

During periods of high runoff, Iron Mountain's acid discharge flows into several creeks that then flow into the Sacramento River's Keswick Reservoir, a source of drinking water for Redding. Mine runoff has been implicated in major fish kills on the Sacramento since 1899, with at least 20 taking place since 1963. In a single week in 1967, a spil from the mine killed 47,000 trout. That's of special concern for the federally Endangered Winter Run chinook salmon, which reaches the upper Sacramento just as winter storms are most likely to bring concentrated acid mine drainage downstream from Iron Mountain.

A paper published in 1999 in the Proceedings of the Natural Academy of Science describes a scene inside the abandoned mine that sounds like nothing so much as a Biblical account of Hell. The mine's ore veins are mainly pyrites, which oxidize in the presence of moisture and oxygen. That chemical reaction produces heat, which speeds up the chemical reactions; a positive feedback loop with dangerous environmental results. The mine's network of tunnels and shafts both replenishes oxygen and allows heat to travel by convection, keeping the whole interior of the mine stoked like a blacksmith's bellows. Ambient temperatures in the mine run about 116 degrees Fahrenheit, and fires were common when the mine was being worked.

The EPA designated Iron Mountain as a Superfund site in 1983, and work started almost immediately to reduce the danger the mine's drainage posed to the Sacramento River watershed. Running the drainage through alkaline lime helped reduce the acidity of the liquid while EPA worked to build water treatment plants onsite.

Though agencies had considered plugging the mine, it turns out that would have been a bad idea even if they'd found a way to seal the mine's tunnels that the acid wouldn't burn through. According to the U.S. Geological Survey, plugging the mine would create a cauldron of confined hot acid mine drainage, as much as 160 million gallons' worth, that would eventually eat through the rock and spill uncontrollably into the Sacramento.

That's 53 Gold King Mine spills. And federal scientists estimate Iron Mountain will be creating acid mine drainage for the next 3,000 years. Something to think about next time someone suggests cutting the EPA's budget.

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.

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