Mine Tailings

The past hundred years or so, mining has been done on such a monumental scale as to literally move mountains. Every kind of mineral and resource is being taken from the Earth. Large and small mining companies are looking for everything from metals such as gold and uranium to other resources such as diamonds and coal. Innovations over the years enabled hundreds of thousands of pounds of rock to be removed and ground up daily in search of the desired products. Many of the materials being mined for are present in such tiny amounts that tons of material are processed in search of a pound or two.

 

The mining industry uses both mechanical and chemical processes to extract what they want from the mined ore. Anything that is not the desired substances is cast off after the process. Mine tailings are the waste product that is generated from a mining operation processing ore.  The National Institute of Health considers mine tailings one of the most dangerous environmental hazards we are facing today. Not only are the tailings themselves dangerous, but the extraction process is not anywhere close to 100% efficient either, so there is always some of the material being mined for leftover in the disposed tailings. This creates additional problems and health risks when the products being mined are radioactive such as uranium or poisonous such as arsenic.

 

Mine tailings are made up of the ground ore that is left and the chemicals or compounds used to extract the targeted metals. Tens of thousands of these piles exist from mining operations closed down years ago, creating a symbol of the industry’s toxic legacy. Thousands more are created every year, and many present danger to the communities and environment. Because there is presently no value to the mining company in the tailings, they get disposed of as cheaply as possible.

 

In 1976 the Resource and Conservation and Recovery Act was passed. Its expressed purpose was to begin regulating hazardous substances and disposal. The mining industry managed in 1978 and 1980 to get much of mining waste excluded from regulations as a hazardous substance. Because of this, mines usually had little or no environmental controls on them, and waste was normally either dumped in giant piles around the mine or run into nearby streams and rivers to be taken away.

 

Mine operators saw the damage their operations were doing to the land and the streams being colored with the metals and acids from the mine drainage. Few people cared back then. It was all about the money. Years of mining without a thought to the environmental hazards to humans and the environment have come back to haunt the people and communities that once were boomtowns. 

 

Some environmental rules and controls put in place during the past 40 years or so have helped limit the damage current mining operations have to some extent, but the tremendous increase in the scale of these operations created different and, in some cases, worse dangers and damage.

 

The mining operations for copper, gold, and uranium give an idea of how big a problem tailings are. The size of mines ranges drastically. Smaller mines produce a couple million pounds of tailing per year, and the largest mines such as the Morenci copper mine in Arizona generate billions of pounds of tailings per year. 

 

A copper mine may produce ore containing copper at 0.6%. That is the average yield of copper ore. That would mean they would need to process 10,000 pounds of copper ore to be left with 60 pounds of copper. The other 9,940 pounds are considered mine tailings and useless to the mine company. They are usually disposed of either in giant piles onsite, used as backfill for filling in old sections of the mine, or placed into a containment pond. An actual amount of copper mined from the Morenci mine in Arizona in 2015 was stated at 902 million pounds. Based on an average of 0.56% copper, which was high for this mine, almost 160 billion pounds of waste rock and tailings was created in a single year. These are accurate numbers the industry group Mining Technology compiled. To put this number in perspective, it is equivalent to 987 Washington Monuments or 784 Navy Aircraft Carriers, not to mention over 13 million elephants. 

 

A gold mine works with a metal content in the ore that is much less. There are a variety of different kinds of gold mines that produce varying amounts of gold and tailings. Underground mines usually have higher yields of gold content in ore. A high quality underground mine produces ore containing eight to ten grams per ton. A lower grade mine may contain only one to four grams per ton. That equates, even in the best scenarios, to a ton of ore having gold content of 0.000011%. To get an ounce of gold, the mine needs to process almost 6,000 pounds of gold ore. 

 

Above ground mines have much lower yields of gold ore. An above ground pit mine has yields of under a gram per ton. The Fort Knox Gold Mine outside Fairbanks, Alaska, in 2018 had a yield of .43 grams of gold per ton of ore. 

 

Furthermore, gold ore mining uses a chemical process to remove the gold from the ore once it is crushed. The main chemical in the process is cyanide. Gold mines remove ore by the thousands of tons. The ore is crushed and ground up, and then cyanide is added to react with the gold. After the gold has been separated, the remaining slurry is a waste product. The amounts of this toxic sludge are staggering. Some mines have millions of gallons of cyanide-laced slurry stored in lagoons that are known to leak.

 

Uranium mining has seen its better days. At its peak, in the 1950s and again in the 1980s, uranium mining had thousands of operations going in a wide variety of sizes. Today, according to the U.S. Energy Information Administration, there are only seven commercially operating mines in the U.S. Uranium has reached a historic low price, and imports meet 90% of the country’s needs, so most mines are closed. The government is the largest producer at this time. 

 

When uranium mining was in its most productive period, between the 1940s and early 1980s, many operations were pulling millions of pounds of ore out of the Earth every year to supply the U.S. Government with uranium for weapons systems and research. At the peak of uranium mining in the U.S., there was almost 43 million pounds of enriched uranium produced in 1980. Tailings were simply placed in huge piles as closely and as cheaply as possible. The Federation of American Scientists estimated over 230 million tons of radioactive mine tailings were produced by the uranium mines. 

 

One of the many disastrous examples of this is the 16 million pound pile left on the banks of the Colorado River in Moab, Utah. The tailings were just piled and left when the uranium boom of the 1980s died. After close to 40 years and many years of fighting for its removal, there are now only six million pounds left sitting on the banks of the Colorado. But rather than actually solve the problem, they simply moved the tailings to another place away from the river and dumped it there.

 

The majority of mining operations use one of several methods to dispose of the vast amount of tailings and waste rock they produce. The easiest and least expensive disposal method was the most frequently used in the past. Much of the tailings and waste rock created by the mining companies was either disposed of into the nearest waterway or simply moved away from the active mining area and dumped, piling it high on any available land. Now, like in the past, small mountains have been created from tailings. These toxic mountains sit in the open, subjected to rain and snow, leaching their toxic wastes into nearby streams and rivers. The winds blow the fine particles into neighboring areas, covering everything with hazardous particulates for locals to breathe. In some states large mining companies have purchased large tracts of open land to use as dumping areas for tailings. This allows them to create and dispose of even more waste ore than ever before. 

 

The main way the tailings are dealt today is the wet method, which creates a toxic, slurry-like material when the ore is processed. The leftover slurry still contains much of the chemicals used to extract the target ore in addition to the balance of the material mined for. The slurry like material is disposed of in enormous pits and lagoons. Many times, the mining company will create an entire toxic lake filled in with the slurry and mine tailings and build a dam to hold the disposal waste in place. Impoundments like this are known to leak, and at times, dams have broken, unleashing hundreds of thousands of gallons into streams, rivers, and the local environment. Millions of gallons of toxic tailing sludge sit near where the mining operation. 

 

There is a slightly better way to process and store the tailings, but it costs the companies more money and, if not required by their permits, they do not use this method. If the tailings are dewatered, they become more of a solid that creates less hazards from blowing away and does not require huge lagoons and unstable dams to hold. They are placed in rows called dry stacking and will remain in place better than dry tailings. Drainage still remains a big issue with the tailings exposed to the elements. Particulates blowing away and runoff contaminated with acid and toxic materials remains a large problem. They remain sitting wherever they were dumped for decades or centuries remaining hazardous. 

 

If there are large open areas available to simply dump and dispose the tailings and waste rock onto, then the mining companies will use that method. In Baghdad, Arizona, a huge mining operation run by Freeport-McMoran bought 16,670 acres of land from the State Trust Land Department to use as a tailing dump. Interestingly, the mining company was the only bidder on the 25 square mile parcel of land at the auction.

 

When mining operations first started in the late 1800s through the mid-1900s, they were mostly located in more rural areas, but growth of towns and cities have brought many more people close to the piles of tailings. This is putting many more people at risk of exposure. Tailing piles are not a harmless pile of rocks. There is real danger in those tailing piles. 

 

1. Inhaling the Particles

 

During processing, the ore is ground into very tiny, fine particles. Because of the small size of the particles, they are easily carried away by the wind. Many communities near mine tailing piles have a continuous coating over their houses and cars. The small size of the tailings allows them to invade the insides of houses, working their way through windows and doors. Due to the small size and light weight of the particles, tailings are able to be blown several miles and more from the dump. Asthma, other lung ailments, and cancer are associated with long-term inhalation of these particulates.

 

Breathing fine particulate matter is already dangerous, but breathing particulate from tailings comes with unique dangers. Depending on the type of mine the tailings are from, they may contain asbestos, lead, arsenic, and many other very harmful chemicals. Quite a few are known to cause cancer and respiratory ailments. High levels of metals contained in the tailings has been measured in humans and found in wildlife. Heavy metals usually found at many of these tailing sites cause adverse health effects such as memory problems, autoimmune issues, digestive problems, and poor kidney function. Metals such as arsenic can cause cancer and are associated with diabetes and heart disease as well. 

 

In the town of Green Valley, Arizona, a mine operated by Freeport McMoRan was issued their fifth violation notice by the county for tailings dust. Tailings blew from the mine’s property into nearby neighborhoods. The company had recently been fined $230,000 for similar violations. 

 

2. Water Contamination

 

Runoff from tailing piles creates a toxic leachate similar to what seeps through and out of a landfill. The liquid leaking from the tailings is full of highly concentrated and toxic chemicals. This seeps into the ground underneath the tailings pile and contaminates underground water used by wells in the area. Much of this toxic liquid does run off the site, creating its own little streams looking for a place to flow to. Sometimes, it is the ditches along the road. Other times, it may be the pond next to a house where children like to play and swim. 

 

In Rimini, Montana, the groundwater is so polluted with contamination left by the 150 mines in the area that residents are unable to use the tap water. The community is listed as a Superfund site, but the pollution continues to flow from the mines, making the groundwater even more contaminated. 

 

In Kent, New York, tailings from an old arsenic mine were disposed throughout the areas near the mine. Back in the 1980s, a couple became seriously ill and almost died; it was discovered they had been poisoned by the arsenic tailings. Their well had been poisoned from arsenic leached from the tailings. The EPA investigated and trucked water in so the house had a safe supply of water to use. At that time the EPA closed the case and moved on. Fast forward to 2019, and now testing that should have been done decades ago revealed private properties in the area near the mine have levels of arsenic in the soil 1,600 times the EPA screening level for the substance. A health advisory the EPA put out in April 2019 told the residents that long-term exposure to arsenic in the soil creates significantly increased risk for cancer. For now, the government put down wood chips over the toxic soil and advises residents to not contact the soil and wash their hands. 

 

In eastern Oklahoma in a mining area known as the Tar Creek district, the groundwater is so polluted that even the surface waters have nothing living in them. The children have elevated levels of lead in their blood, and that has not changed for almost 20 years as there is no real end in sight for a clean up to change this. 

 

3. Exposure to Tailings Directly

 

In many of these old mines, the tailings piles are exposed, and the property is accessible to anyone who wants to go there. Many large mining areas near cities such as Butte, Montana, are home to hundreds of open and accessible piles of mine tailings. Chronic exposure to many of the metals in the tailings can lead to kidney damage, bone and lung disease, and some cancers. Many mine tailings contain radioactive substances and may have high enough levels to cause harm. Thousands of old uranium mines left tailings piled all around, still blowing radioactive dust into nearby communities for the residents to inhale. Kidney problems, liver issues, and cancer are a few of the potential health effects from exposure to these tailings. 

 

South of St. Louis, Missouri, the Big River Mine Tailings waste site is contaminated with lead, cadmium, and zinc from old lead mining activities in the region. Dozens of homes are contaminated for the tailings that were used for driveways and fill projects. The large piles of tailings have eroded over the years, and lead has blown throughout the area. The EPA is testing the children in the nearby community for lead in their blood. There were at least 89 properties with unsafe lead levels in their soil. 

 

In Dewey, Arizona, one old mining and tailings disposal area that is also a Superfund site has children playing and teens hanging out on the tailing piles. The EPA put nine signs up to keep people out. In the meantime, there isn’t even a fence there after decades of exposure. The EPA found out the teens were disregarding the posted signs and issued a warning to the residents to stay out of the hazardous areas. There still is no fence around the area considered so dangerous it is a Superfund site. The locals continue to play near the area, possibly thinking if the EPA did not fence it off, it may not be as dangerous as they said. 

 

4. Tailing Dam Failures and Leaks

 

For mines using the wet method of disposal, the tailings end up in large ponds that can cover hundreds of acres and hold millions of gallons of tailings. There have been many instances when the dams that hold back these ponds have had structural issues. Leaks are more common than most people are aware. 

 

And it’s not just ponds. Some mining operations fill old quarries or dam off canyons to use as places to dispose of their waste. Heavy metals, acids formed by the ore, and waste rock and other toxic elements eventually wind up in the streams and rivers nearby to the tailings’ containment.

 

According to a review of data by the news agency Reuters, tailing dams in the United States are built using an architectural method that is not considered safe by engineers. 

 

The challenge of mine tailings is not going to become any easier in the future. Through advances in technology, the mining industry is able to use lower grade ore than before. However, that will result in millions of more tons of rock being discarded as mine tailings and waste. 

 

We cannot expect the mining industry to solve this problem themselves because there is no incentive for them to do so. The industry gets nothing at all in return for taking care of its waste problem. It costs them money, which they interpret as taking profit and throwing it away. The mining industry spends vast amounts of money on lobbying the government and politicians to keep regulations in their favor. Whenever possible, they try to weaken the few existing regulations to their advantage. 

 

Currently, the Department of Interior is making it easier for the mining industry to profit and ravage our national lands. Newer regulations favor the industry, not the people or the environment.

 

There are no really great choices for a really sensible working solution. Covering up a pile of tailings with a dirt cap is not a real solution for future generations. The tailings are still underneath, poisoning the groundwater with leachate. The toxic leachate from the giant piles will continue to be a hazard for many decades no matter what we do. The only real partial solution is to remove the piles of tailings and place them into a more secure, double lined containment area (which will eventually leak too). The monumental amount of tailings needing to be handled makes any solution at this time unviable. 

 

If the town you live in is an old mining town or currently is the site of operating mines, check to see what they do with the tailings and where they are located. Make sure your family is aware of the places to stay away from. If you live near a tailings pile, check with your state and local environmental agencies to see what you are being exposed to. There is no doubt you are being exposed to particles that may be dangerous. 

 

Because of the airborne particles from many of the tailing piles and lagoons, distancing yourself 2-3 miles is advisable. If there is a large impoundment holding back millions of gallons of tailings, be certain that if there is a breach in the dam or other failure, you are not directly in the path the tailings will take. It is also imperative you have your water tested annually for heavy metals and any other contaminants which may be present in the aquifer you get your water from.