Al Gedicks’ Letter to Committee on Michigan’s Mining Future
To: Committee on Michigan’s Mining Future
From: Al Gedicks, Wisconsin Resources Protection Council
Re: Climate Change and Mine Waste Disposal
Climate Change Poses a Risk to Mining Infrastructure
The committee recognizes that “climate change increases the risk of hazardous events” that can damage mining infrastructure. Apart from the mine itself, the largest mining infrastructure on the surface are the contact water basin and the tailings impoundment. Tailings storage facilities are some of the largest human made structures on earth ( Mine Tailings Storage Is No Accident. United Nations Environmental Programme, 2017).
For the proposed Back Forty metallic sulfide mine, the contact water basin would hold 161 million gallons of water contaminated with mine waste. The tailings impoundment, or tailings management facility (TMF) would contain 5.9 million cubic yards of waste rock and 4.9 million cubic yards of tailings (Aquila Resources, “Design of Back Forty Tailings Management Facility, October 16, 2019).
When the TMF is fully constructed it will cover a total footprint area of 124 acres and reach a height of 138 feet. The maximum volume of water allowed in the tailings decant area will be 39.6 million gallons.
The committee also recommends that “Mining project designs should plan for extreme weather events of a given magnitude considering the effects of climate change and not simply rely on past ‘climate norms’” (p. 8).
https://www.michigan.gov/documents/egle/2021-08-20-cmmf-report-2021_733334_7.pdf
The committee avoids the controversial issue of tailings dam safety
However, when the committee addressed the “permanent management of sulfide containing tailings” they avoided one of the most controversial issues of the mining industry: the safety of tailings dam construction and the causes of tailings dam failures.
This directly contradicts the committee’s recommendation to plan mining project designs that can withstand extreme weather events.
Rather than confront these issues, the committee dismissed the issue as too time-consuming and beyond the scope of the committee. The issue was relegated to a policy subcommittee where the issue will receive even less attention. This is a shameful abdication of the public trust responsibility to recognize the science of tailings dams that are prone to fail and threaten the lives and livelihoods of downstream communities.
Tailings dam safety cannot be ignored
This is not a hypothetical situation. Aquila Resources has recently withdrawn its second dam safety permit application for the proposed Back Forty metallic sulfide mine next to the Menominee River. The company plans to submit a new dam safety permit application to EGLE by the end of 2021.
Aquila’s previous dam safety applications have proposed the controversial upstream dam design that uses crushed waste rock and sandy soil – not steel and concrete – to build a retention dam for mine tailings. Tailings are the waste material left over from the crushing and chemical processing of mineral ores like copper, zinc and gold. In other words, part of the wall containing the tailings is constructed of waste rock and the tailings themselves, band upon band of compacted sludge. This factor, according to the journal Science, has resulted in a failure rate that, “over the past century was more than 100 times higher than that of reservoir and power dams, according to one estimate ( Warren Cornwall, “A Dam Big Problem, Science, August 2020, vol. 369, p.907-908).
Furthermore, that wall is designed to grow as more and more waste is pumped in. The upstream dam design is the lowest cost dam design but also the most prone to failure, according to experts. About 76 percent of the tailings dam failures worldwide are related to the upstream construction method (International Commission on Large Dams, 1996, Monitoring of tailings dams, review and recommendations).
Brazilian tailings dam disaster in January 2019
The most recent example of the failure of the upstream tailings dam design is the January 2019 Brazilian dam failure that released almost 3 billion gallons of sludgy mine waste and killed over 270 people in Brazil’s deadliest-ever mining accident. The spill contaminated 75 miles of the Paraopeba River, where mud, debris and dead fish have devastated the Pataxo indigenous people who depend upon the river for drinking, fishing and irrigation.
Since the accident, the mud has traveled almost 200 miles on its way to the ocean. According to the environmental foundation SOS Mata Atlantica, the Paraopeba River is currently unsuitable for aquatic life (Eduardo Campos Lima, “Research Unveils New Damage Caused by Brazil’s Failed Fundao Dam,” Hakai Magazine, March 8, 2019.
The biggest known spill by volume in a century occurred in Brazil in 2015 at the Samarco mine in Mariana. This spill buried three communities and killed 19 people, leaving hundreds homeless and contaminating hundreds of miles of river valleys with toxic sludge. Seventeen days later, the toxic tide reached the Atlantic Ocean, more than 400 miles away. The collapsed dam was an upstream dam design.
Brazil bans the upstream dam design; insurers won’t cover industry liability
Brazil has already banned this design from further use and ordered the decommissioning of 88 existing dams employing this design. Chile, Peru and Ecuador have also banned this design. The American International Group (AIG) has cut back the vast majority of its mining liability insurance in response to the Brazilian disaster.
There are alternative dam designs but they are more expensive
An alternative dam design prebuilds the tailings dam walls and insulates them. “Experts prefer these dams as safer,” according to Bloomberg,” but there’s no absolute guarantee of stability. The most expensive technique, costing as much as 10 times the cheapest method, dries out the tailings and stacks them, typically underground.” This is the “dry stack” design. (Danielle Bochove, et. al, “Brazil’s Deadly Dam Collapse Could Force the Mining Industry to Change,” Bloomberg Businessweek, February 20, 2019).
Tailings dam failures are increasing in frequency and severity
Catastrophic tailings dam failures are not isolated events. Since 1960, there have been over 100 occurrences of collapsed tailings dams or impoundments around the world that have often had dire consequences (WISE Uranium, 2015, (http://www.wise-uranium.org/mdaf.html).
A recent study reveals that mining waste failures are increasing in frequency and severity because lower ore grades have necessitated larger, open pit mines for economies of scale. As mines grow bigger, they generate larger volumes of waste, stacked into higher tailings dams. “Extracting a single kilogram of copper can now produce 200 kilograms of sludge,” according to the journal Science (August 2020).
According to Dr. David Chambers, an internationally recognized expert on tailings dam failure, “These dam failures are not limited to old technology or to countries with scant regulation. Previous research indicates that most tailings dam failures occur at operating mines and 39 percent of such failures worldwide occur in the United States, significantly more than in any other country.” (https://www.nps.gov/articles/aps-v13-i2-c8.htm)
“These failures,” according to Chambers and Lindsay Newland Bowker, “are a direct result of the increasing prevalence of tailings storage facilities (TSF’s) with greater than a 5 million cubic meter total capacity necessitated by lower grades of ore and higher volumes of ore production required to attain or expand a given tonnage of finished product.” (The Risk , Public Liability & Economics of Tailings Storage Facility Failures) (https://files.dnr.mn.us/input/environmentalreview.polymet/request/exhibit3.pdf)
Aquila’s most recent dam safety application proposes to store a combined total of 10.8 million cubic yards of waste rock and tailings (Aquila Resources, “Design of Back Forty Tailings Management Facility, October 16, 2019).
Upstream tailings dams are more unstable than other dam designs
Aquila and EGLE claim that the finely ground cyanide-laden wastes, along with millions of gallons of water mixed in a slurry, can be stored safely next to the Menominee River in perpetuity. There is no scientific evidence to support this assertion.
The most recent scientific study demonstrates that “active upstream facilities report a higher incidence of stability issues (18.3%) than other facility types, and that this elevated risk persists even when these facilities are built in high governance settings.” (Daniel M. Franks et al., “Tailings facility disclosures reveal stability risks,” Scientific Reports, March 2021 11:5353, https://doi.org/10.1038/s41598-021-84897-0
Stronger storms are the new norm of climate change
The causes of tailings dam failures are numerous. Apart from construction problems, stronger storms dumping water into dams that weren’t designed to handle the weight have generally not been considered in the design and construction of existing tailings dams ( Mine Tailings Storage: Safety Is No Accident, United Nations Environment Program, 2017, p. 31).
Recent heavy downpours around the world from Germany, to India, and China have caused extensive flooding and hundreds of deaths. On August 21, 2021, more than 17 inches of rain fell on Tennessee causing flash floods and 21 deaths. These extreme flooding events were made more likely by climate change.
As the climate warms, increased evaporation pumps more moisture into the air. “And warmer air can hold more moisture – about 7 percent more with every degree Celsius of warming, or 1.8 degrees Fahrenheit (which is about how much the world has warmed since preindustrial times). That means when it rains, it tends to rain more.” (Aatish Bhatia and Nadja Popovich, “Tracking Two Americas: One Parched, One Soaked,” New York Times, August 28, 2021).
According to James Kuipers, a consultant for the EPA on tailings dams, a heavy downpour can rapidly increase the weight of the material inside the dam and liquefy relatively dry mine waste that can then spill out, overwhelming and drowning people in its path (Stephen Lee, “Brazil Dan Catastrophe Sounds Alarm for U.S. Waste Ponds, Bloomberg Environment and Energy Report, February 4, 2019).
Aquila’s amended mine permit application minimizes the potential for external erosion of the tailings dam from the runoff of rain water by using 18 year old data on the severity of storms. It is not sound science to predict the safety of tailings dams on such old data. Heavy rain has been implicated in 25 percent of global and 35 percent of European tailings dam failures (M. Rico et. al, 2008. “Reported tailings dam failures: a review of the European incidents in the worldwide context, Journal of Hazardous Materials, 152, pp. 846-852).
The Great Lakes region is warming faster than the rest of the U.S. and this trend is likely to bring more extreme storms to the region, according to a study commissioned by the Chicago-based Environmental Law & Policy Center (John Flesher, “Report: Great Lakes seeing effects of warming, Associated Press, March 24, 2019). New research from the National Academy of Sciences warns that the likelihood of intense storms is rising rapidly in North America and projects big increases in such deluges. (Bob Berwyn, “New Study Shows Global Warming Intensifying Extreme Rainstorms Over North America,” Inside Climate News, June 2, 2020).
The risks associated with tailings dams are not confined to catastrophic failures
The increased frequency and intensity of heavy rainfall and wetter conditions could pose a “slow motion environmental problem” from increased percolation into the waste layer of store and release covers leading to increased flushing of contaminants (acid rock drainage) and release into the environment. (“Climate Change and Acid Rock Drainage – Risks for the Canadian Mining Sector,” Mine Environment Natural Drainage Program, MEND Report 1.61.7, September 26, 2011).
Guidelines to end mine waste disasters
In June 2020 an international group of 142 scientists, community groups and NGOs from 24 countries published a set of 16 guidelines for the safer storage of mine waste. The guidelines aim to protect communities, workers and the environment from the risks posed by thousands of mine waste storage facilities which are failing more frequently with more severe outcomes.
Among the guidelines are the following:
Tailings storage facilities must be built and managed only with community consent, respecting human rights and the rights of Indigenous Peoples, adopting the best available technologies and practices.
The Board of Directors must bear the prime responsibility for the safety of tailings facilities, including the consequences of dam failures, and demonstrate that the company has the necessary financial assurance to cover the full cost of closure and post-closure plans as well as public liability insurance to cover the full cost of any catastrophic failures.
The use of upstream dams must be banned in favor of centerline and downstream dams which are much less vulnerable to all mechanisms of dam failure. Additionally, dams must not be built in close proximity to communities or above mining infrastructure where workers are likely to be present.
Jan Morrill et al. (2020) Safety First: Guidelines for Responsible Mine Tailings Management, Earthworks and MiningWatch Canada
Safety First: New Report Outlines Guidelines To End Mine Waste Disasters