Mine Waste Dams Threaten the Environment, Even When They Don’t Fail
Scars from large mining operations are permanently etched across the landscapes of the world. The environmental damage and human health hazards that these activities create may be both severe and irreversible.
Many mining operations store enormous quantities of waste, known as tailings, onsite. After miners excavate rock, a processing plant crushes it to recover valuable minerals such as gold or copper. The leftover pulverized rock and liquid slurry become tailings, which often are acidic and contain high concentrations of arsenic, mercury and other toxic substances.
Mining companies store tailings forever, frequently behind earth-filled embankment dams. Over the past 100 years, more than 300 mine tailing dams worldwide have failed, mainly due to foundation weakening, seepage, overtopping and earthquake damage.
We are research scientists studying how humans affect rivers. In our view, the damage caused by stored mine waste often outweighs the benefits that mining provides to local economies and the technology industry.
This issue is especially urgent now in a region of the Pacific Northwest where Alaska and British Columbia meet. This zone, known as the Golden Triangle, is studded with mineral claims and leases. We believe that rivers in this area could be severely damaged if proposed mega-projects are allowed to proceed.
Catastrophic Failures Renew Old Worries
Tailings dam failures range from the 1966 Aberfan disaster that buried a Welsh village to multiple spills over the past decade in Canada, China, Chile and the United States. The International Commission on Large Dams, a nongovernmental organization, warned in 2001 that the frequency and severity of tailings dam failures was increasing globally.
Two catastrophic and highly publicized failures at the Mt. Polley dam in Canada in 2014 and the Brumadinho dam in Brazil in 2019 finally catalyzed a response. The International Council on Mining and Metals, the United Nations Environment Programme and the independent organization Principles for Responsible Investment drafted a "global standard for the safe and secure management of mine tailings facilities." The first public review of the standard was completed in December 2019, and its authors plan to finalize their recommendations by the end of March 2020.
The standard aspires to achieve "zero harm to people and the environment and zero tolerance for human fatality." Reducing the likelihood of future dam failures and minimizing damage if one does break are appropriate goals, but our research suggests that the concept of "zero harm" is false and potentially dangerous.
Why? Because once in place, tailings dams and their toxic reservoirs require maintenance forever. Even if there is no catastrophic failure, these dams and their surrounding infrastructure can cause ecological harm in multiple ways. They require artificial water diversions and releases, which upset natural flow patterns in surrounding streams and modify water temperature and concentrations of metals. And polluted groundwater seepage from unlined reservoirs or failing liners is often hard to detect and treat.
These ecosystem modifications directly affect organisms on land and in the water downstream. Every decision to allow a mine to proceed with a tailings storage facility indelibly transforms rivers and their ecosystems for hundreds to thousands of years.
International Rivers at Risk
Today these decisions loom large in the Golden Triangle, home to the Taku, Stikine and Unuk Rivers – three of the longest undammed rivers in North America. Salmon from these rivers have supported indigenous communities for millennia, generate tens of millions of dollars in economic activity annually and provide a dependable source of food for organisms ranging from insects to brown bears.
We calculate that 19% of the total drainage area of these three rivers is staked with mineral mining claims or leases. This includes 59% of the Unuk River watershed, along with the entire Iskut River corridor, the largest tributary to the Stikine River.
We have identified dozens of mines in exploratory or production phases. Some industry representatives call these statistics irrelevant because only a small portion of the claims will convert to economically viable projects. But from our perspective, the fact that vast areas of these watersheds are included in initial explorations implies that few rivers in this region are safe from potential mining development.
Most proposed projects in the Golden Triangle will require open pit mining and tailings storage. As one indicator of their potential scale, the Red Chris Mine, which has operated since 2015 in the headwaters of the Stikine River, maintains a tailings reservoir dam that is permitted to ultimately stand 344 feet (105 meters) high and contain approximately 107 billion cubic feet (305 million cubic meters) of tailings. The heights of the failed dams at Mt. Polley and Brumadinho were 131 feet (40 meters) and 282 feet (86 meters), respectively.
Those heights pale in comparison to dams proposed for three metal mines in the Stikine and Unuk watersheds, including KSM, Galore Creek, and Schaft Creek. The tallest of four dams planned for KSM would measure 784 feet (239 meters) – one of the highest dams in North America, and the second highest in Canada.
At KSM, economically viable ore will be transported from open pits to a processing facility and tailings storage reservoir, accessed via twin tunnels built under a glacier. After what the project proponent calls the 53-year "life of mine," Seabridge Gold proposes to treat runoff water from the piled waste rock for at least 200 years.
Each component of these proposed mines is an incredible engineering feat that will cost billions of dollars to construct and more to clean up later. From the perspective of maintaining an ecologically healthy watershed, the life of the mine is just beginning when operations close.
In contrast to more conventional water storage dams, which are licensed and built for a finite operating life, tailings dams must hold back their slurry forever. The likelihood of leaks or dam failure compounds over this multigenerational time period as facilities age and projects no longer generate revenue.
Accurately Assessing Risk
Rivers are the arteries of coastal Alaska and northwestern Canada, draining pristine snow and ice-covered mountains and pumping out cold, clean water to support fish, wildlife and people. Here and elsewhere, we believe that regulators should take a measured and cautious view of current and planned tailings facilities.
Dam failures are increasing in frequency, and often are so large that true cleanup or reclamation is not possible. Before more are built, we see a need for independent science to provide a means of honestly assessing the risk of storing mining waste.
Reposted with permission from The Conversation.
- Controversial Amazon Gold Mine Close to Getting Permit, Say ... ›
- 58 Dead, 305 Missing in Brazilian Dam Collapse - EcoWatch ›
- Russian Mining Giant Admits to Polluting the Arctic With Wastewater - EcoWatch ›
At first glance, you wouldn't think avocados and almonds could harm bees; but a closer look at how these popular crops are produced reveals their potentially detrimental effect on pollinators.
Migratory beekeeping involves trucking millions of bees across the U.S. to pollinate different crops, including avocados and almonds. Timothy Paule II / Pexels / CC0<p>According to <a href="https://www.fromthegrapevine.com/israeli-kitchen/beekeeping-how-to-keep-bees" target="_blank">From the Grapevine</a>, American avocados also fully depend on bees' pollination to produce fruit, so farmers have turned to migratory beekeeping as well to fill the void left by wild populations.</p><p>U.S. farmers have become reliant upon the practice, but migratory beekeeping has been called exploitative and harmful to bees. <a href="https://www.cnn.com/2019/05/10/health/avocado-almond-vegan-partner/index.html" target="_blank">CNN</a> reported that commercial beekeeping may injure or kill bees and that transporting them to pollinate crops appears to negatively affect their health and lifespan. Because the honeybees are forced to gather pollen and nectar from a single, monoculture crop — the one they've been brought in to pollinate — they are deprived of their normal diet, which is more diverse and nourishing as it's comprised of a variety of pollens and nectars, Scientific American reported.</p><p>Scientific American added how getting shuttled from crop to crop and field to field across the country boomerangs the bees between feast and famine, especially once the blooms they were brought in to fertilize end.</p><p>Plus, the artificial mass influx of bees guarantees spreading viruses, mites and fungi between the insects as they collide in midair and crawl over each other in their hives, Scientific American reported. According to CNN, some researchers argue that this explains why so many bees die each winter, and even why entire hives suddenly die off in a phenomenon called colony collapse disorder.</p>
Avocado and almond crops depend on bees for proper pollination. FRANK MERIÑO / Pexels / CC0<p>Salazar and other Columbian beekeepers described "scooping up piles of dead bees" year after year since the avocado and citrus booms began, according to Phys.org. Many have opted to salvage what partial colonies survive and move away from agricultural areas.</p><p>The future of pollinators and the crops they help create is uncertain. According to the United Nations, nearly half of insect pollinators, particularly bees and butterflies, risk global extinction, Phys.org reported. Their decline already has cascading consequences for the economy and beyond. Roughly 1.4 billion jobs and three-quarters of all crops around the world depend on bees and other pollinators for free fertilization services worth billions of dollars, Phys.org noted. Losing wild and native bees could <a href="https://www.ecowatch.com/wild-bees-crop-shortage-2646849232.html" target="_self">trigger food security issues</a>.</p><p>Salazar, the beekeeper, warned Phys.org, "The bee is a bioindicator. If bees are dying, what other insects beneficial to the environment... are dying?"</p>
EcoWatch Daily Newsletter
Australia is one of the most biodiverse countries in the world. It is home to more than 7% of all the world's plant and animal species, many of which are endemic. One such species, the Pharohylaeus lactiferus bee, was recently rediscovered after spending nearly 100 years out of sight from humans.
Scientists have newly photographed three species of shark that can glow in the dark, according to a study published in Frontiers in Marine Science last month.
- 10 Little-Known Shark Facts - EcoWatch ›
- 4 New Walking Shark Species Discovered - EcoWatch ›
- 5 Incredible Species That Glow in the Dark - EcoWatch ›
FedEx's entire parcel pickup and delivery fleet will become 100 percent electric by 2040, according to a statement released Wednesday. The ambitious plan includes checkpoints, such as aiming for 50 percent electric vehicles by 2025.
- Which Is Worse for the Planet: Beef or Cars? - EcoWatch ›
- Greenhouse Gas Levels Hit Record High Despite Lockdowns, UN ... ›
- 1.8 Billion Tons More Greenhouse Gases Will Be Released, Thanks ... ›