Comments on Back Forty Mining Permit Amendment Application
by Al Gedicks
Wisconsin Resources Protection Council
agedicks@eagle.uwlax.edu
Tailings Dams Are the Biggest Environmental Disaster Threat of Modern Mining
My main concern with the amended permit application is with the expansion of the Tailings Management Facility which largely accounts for the mine’s footprint expanding by some 200 acres. This tailings dam is supposed to hold back millions of gallons of water mixed in a slurry with finely ground chemical-laden waste rock left over after crushing and processing and then piped into a tailings pond. As the United Nations Environmental Program has noted, “Despite good intentions and investments in improved practices, large storage facilities, built to contain mine tailings can leak or collapse. These incidents are even more probable due to climate change effects. When they occur, they can destroy entire communities and livelihoods and remain the biggest environmental disaster threat related to mining” (see “Mine Tailings Storage: Safety Is No Accident” at www.grida.no/publications/383).
The most recent tailings dam disaster occurred on January 25, 2019 in southeastern Brazil when a tailings dam in Brumadinho released 3 billion gallons of sludgy mine waste, killing 169 people, leaving nearly 200 more still missing (see https://www.bbc.com/news/science-environment-47159216). Vale, the corporate owner of the mine and the world’s largest iron ore and nickel producer said “The dam had a safety factor in accordance with the world’s best practices” ( see https://www.nytimes.com/interactive/2019/02/09/world/americas/brazil-dam-collapse.html?action=click&module=Top%20Stories&pgtype=Homepage).
Since 2014 there have been seven failures significant enough to make international news. These occurred in Canada, Mexico, Brazil, China, USA and Israel (World Information Service on Energy and Uranium-Project, http://www.wise-uranium.org). Between 2008 and 2017, there were 27 serious or very serious failures of tailings dams –up from 19 failures during the period between 1998 and 2007, according to a database managed by Dr. David Chambers, an internationally-recognized expert on tailings dams and director of the Center for Science in Public Participation.
Aquila’s amended permit application paints a rosy picture of the Back Forty project
In the 900 pages of Aquila’s mining permit amendment application there is a systematic and scientifically unjustified dismissal of the potential for pipeline spills, tailings spills, tailings impoundment failures and other releases of hazardous materials. The economic and environmental costs of these releases are not covered in either state or federal financial assurance programs even though they commonly occur at metallic sulfide mines.
In a recent report, Earthworks reviewed state and federal documents and a federal database for fourteen copper sulfide mines representing 89% of copper production in 2010 – the most recent data available from the U.S. Geological Survey. They found that tailings spills have occurred at nine operations, and a partial failure of the tailings impoundment occurred at four out of fourteen mines (28%). (see https”//www.earthworksaction.org/files/publications/Porphry_Copper_Mines_Track_Record_-8012.pdf) “These failures resulted in a variety of environmental impacts, such as contamination of drinking water aquifers, contamination and loss of fish and wildlife and their habitat, and risks to public health. In some cases, water quality impacts are so severe that acid mine drainage will generate water pollution in perpetuity.”
Aquila’s public statements suggest that these failures are the result of outmoded mine practices and lack of regulations. However, a recent study on catastrophic mine waste disasters reveals that these failures are increasing in frequency, severity and costs all around the world. Nearly half of all recorded “serious failures” happened in modern times, between 1990 and 2010. “These failures,” according to Chambers and Bowker (2015), are a direct result of the increasing prevalence of 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.” (see https://files.dnr.mn.us/input/environmentalreview/polymet/request/exhibit3.pdf).
In Aquila’s original mine permit application, they proposed to store 5.1 million cubic meters of tailings, thereby increasing the risk of a tailings spill, according to the scientific literature. In Aquila’s amended application, they propose to store 4.9 million cubic meters of tailings, despite the increased size of the tailings dam. The 4.9 million estimate does not take account of the company’s stated plans for an underground mine after the excavation of the open pit.
The “Upstream” Dam Construction Method is the most prone to failure
A 2017 Columbia University study on tailings dam failures found miners typically choose the upstream dam design because it is the lowest cost option when constructing the dams (see http://water.columbia.edu/files/2019/01/TSF-paper-CWCrev2.pdf). This design is also the most prone to failure, according to experts. About 76% of the incidents worldwide are related to upstream construction methods (International Commission on Large Dams, 1996, bulletin 104, Monitoring of tailings dams, review and recommendations). Instead of using steel and concrete, as is typical in dams at reservoirs holding water, mining dams are made of mining waste itself, band upon band of compacted sludge.
“A tailings dam may look safe, but it’s still retaining a lot of moisture behind it,” according to Dermott Ross-Brown, a mining industry engineer who teaches at the Colorado School of Mines. “They’re inherently dangerous structures.” After the January 25, 2019 tailings dam collapse in Brumadinho, Brazil, all 10 of Vale’s dams using the upstream design were closed down. The Brazilian Institute for the Environment and Renewable Natural Resources fined Vale $250 million for the social and environmental catastrophe. Brazilian courts have ordered Vale to set aside about $2.9 billion to pay for damages caused by the dam collapse (see https://www.nytimes.com/2019/01/27/world/americas/brazil-dam-brumadinho.html)
The only reason the upstream design is considered the lowest-cost option is because mining companies fail to assess the cost of a collapsed dam. Aquila’s financial assurance cost only covers costs for the end of construction operating period and the Life of Mine operating period.
Golder report omits any risk assessment of a tailings dam disaster
Despite the track record of tailings dam failures the Golder report on Aquila’s tailings dam omits any risk assessment of such an event on the social fabric of communities or the environment. Communities can suffer death and destruction of homes, income and the environment. Some of these community impacts may be long-lasting if drinking water is polluted, fish and wildlife habitat destroyed and tourism and recreational opportunities around the Menominee River are lost.
Mental health impacts from tailings dam failures also need to be recognized. People feel grief, loss and anger when destruction affects their environment and their sense of place. When the Brazilian dam broke in Brumadinho, Guy (Anahkwet) Reiter, a Menominee tribal member said: “It hurts my heart to think that this could possibly happen to the Menominee River and the people depending on it to survive. Even more so that we as Menominee people who come from that river and have a connection that leads back for thousands of years. The river holds memory, it knows our deep connection. The river is the center of our universe. We look to it to be reminded that we must always keep moving.”
Sociologists have documented that “one can speak of traumatized communities as something distinct from assemblies of traumatized persons. Sometimes the tissues of community can be damaged in much the same way as the tissues of mind and body…traumatic wounds inflicted on individuals can combine to create a mood, an ethos—a group culture, almost,– that is different from (and more than) the sum of the private wounds that make it up. Trauma, that is, has a social dimension.”
(see Kai Erikson, A New Species of Trouble: The Human Experience of Modern Disasters (New York: W.W. Norton, 1994, pp. 230-231).
Upstream embankments are not suited to areas of seismic activity
According to the Golder report in Appendix C of the amended application, “With the upstream construction method, tailings liquefaction represents a potential mode of failure, which needs to be evaluated.” Liquefaction, or the sudden loss of strength when tailings sands are loaded and cannot drain, can be triggered by seismic events, such as an earthquake. When liquefaction occurs, “a solid material seemingly resting safely in place can abruptly become a murky liquid, flowing downhill and destroying nearly everything in its path.” (see “A Tidal Wave of Toxic Mud,” New York Times, February 10, 2019)
Chile, Peru and other earthquake-prone countries ban the design, in which tailings are used to progressively construct dam walls the more a mine is excavated. Even small seismic activity has been shown to affect tailings dams.
Golder dismisses this possibility by asserting, without evidence, that the project is located in an area of low seismicity. However, in 2010, a massive split in the ground, called the “Menominee Crack” mysteriously opened just north of Menominee and is considered to be the result of a small earthquake.(see Becky Oskin, “What Caused This Weird Crack to Appear in Michigan?” Live Science, February 9, 2016; Samantha Matthewson, “Menominee Crack: Michigan Researchers Finally Identify Mysterious Pop-Up Feature,” Nature World News, February 11, 2016; Joshua P. Richardson et al. “Menominee Crack: Bedrock Pop-Up Event near Menominee, Michigan,” Geo Science World, 87:2A, March-April 2016).
The split, which measures almost 360 feet long and 30 feet wide at its largest point, formed in October 2010 following a magnitude-1 earthquake. Scientists from Michigan Technological University proposed that this seismic event, which they called a “pop up” probably occurred “when underground pressure on the limestone rock in the area was released. Pop ups are common in quarries in the eastern US, where rock removal releases pent-up strain in the underlying rocks. Golder has failed to consider the risk of liquefaction of the tailings as a result of dynamic loading by a small earthquake.
Risk of dam failure from heavy rains is underestimated
The causes of tailings dam breakage are numerous. Apart from construction problems, stronger storms dumping water into dams that weren’t designed to handle the weight are cited in a review of tailings dam failures in Geotechnical News Magazine in December 2010. Aquila’s amended 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 (see 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).
James Kuipers, principal consulting engineer at Kuipers and Associates LLC states that 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. Kuipers is a consultant with the EPA and state governments on tailings dams. (see Stephen Lee, “Brazil Dam Catastrophe Sounds Alarm for U.S Waste Ponds, Bloomberg Environment and Energy Report, February 4, 2019).
According to the chief scientist at Climate Central, “Across the board, the United States has seen an increase in the heaviest rainfall events, and the Midwest specifically has seen an increase of almost 40 percent.” In August 2018, in Wisconsin’s Coulee Region and Vernon County in particular, was hammered by heavy rains that caused two dam failures and damaged at least five more dams.
The public needs information on the potential volume of tailings release, the chemical composition of the tailings release, and the flow of tailings release to the Menominee River and wetlands under both dam break and dam failure scenarios.
Risk of dam failure from stress increase is underestimated
Two of the potential triggers for liquefaction are stress increase due to a dam rise and stress concentrations due to a higher dam (see Klohn Crippen Berger, “Static Liquefaction and Strength Loss in Tailings Dams” posted on April 11, 2018. Available at https://www.klohn.com/blog/static-liquefaction-strength-loss-tailings dams/). Appendix C of the Golder Report states that the project site is typically covered with topsoil underlain by a variable thickness of silty sand overburden soil of very loose to loose relative density.
This layer of weak glacial deposits may make the tailings storage facility design inappropriate for the site. The government of British Columbia’s expert commission on the 2014 Mount Polley tailings dam disaster found that a breach occurred suddenly in the Perimeter Embankment of the tailings dam as a result of foundation failure. They concluded that the tailings dam was not appropriate for the site because it did not take into account the underlying geology.
The Characteristics of Tailings Dams Constitute a Form of Accident that is Inevitable
Charles Perrow, an expert on complex organizations, has suggested that tailings dams are high-risk systems that have some special characteristics, beyond their release of toxic wastes, that make accidents in them inevitable, even “normal” (see Normal Accidents: Living With High Risk Technologies, New York, Basic Books, 1984).
This has to do with way failures can interact and the way the system is tied together. The argument is basically very simple. The tailings dam has a lot of parts, procedures and operators. Then two or more failures among components interact in some unexpected way. No one dreamed that the speed at which the liquefaction of the tailings at the Brumadinho tailings dam occurred would make it impossible to trigger the warning sirens and save lives. If the alarm had sounded, the dam would have still collapsed, but no one would have died.
Furthermore, no one could figure out the interaction at the time and thus know what to do. The problem is just something that never occurred to the designers. Perrow calls this the “interactive complexity” of the system. By itself, interactive complexity does not necessarily result in accidents. But in the case of tailings dams, the system is also “tightly coupled,” that is, processes happen very fast and can’t be turned off and the failed parts cannot be isolated from other parts. If interactive complexity and tight coupling – system characteristics – inevitably will produce an accident, Perrow calls it a normal accident, or a system accident. The odd term normal accident is meant to signal that, given the system characteristics, multiple and unexpected interactions of failures are inevitable.
The Independent Expert Engineering Investigation and Review Panel on the Mount Polley Tailings Dam Disaster would agree with Perrow’s analysis: “Tailings dams are complex systems that have evolved over the years. They are also unforgiving systems, in terms of the number of things that have to go right. Their reliability is contingent on consistently flawless execution in planning, in subsurface investigation, in analysis and design, in construction quality, in operational diligence, in monitoring, in regulatory actions, and in risk management at every level. All of these activities are subject to human error (see https://www.mountpolleyreviewpanel.ca/sites/default/files/report/ReportonMountPolleyTailingsStorageFacilityBreach.pdf)