April 2019 Newsletter
April 3, 2019
Dear WRPC Member and Friends of the Menominee River,
Aquila’s full-page ad in the March 2, 2019 edition of the Eagle Herald sought to reassure the public about the safety of the Back Forty’s proposed tailings storage facility in light of the recent Brazilian tailings dam disaster that killed over 200 people with an estimated 91 others still missing and presumed buried under mud. This is Brazil’s deadliest-ever mining accident. A steady stream of letters to the editor of the Eagle Herald have expressed serious public concerns about the safety of Aquila’s tailings dam design.
Brazilian tailings dam disaster should raise red flags for Michigan regulators
On January 25, 2019, a 28-story high tailings dam in Brumadinho, in southeastern Brazil failed, releasing almost 3 billion gallons of sludgy mine waste. The spill flooded homes, submerging cars and buses under a river of reddish-brown sludge. Brazilian prosecutors have charged Vale, the owner of the dam and the world’s largest iron ore mining company, with efforts to conceal evidence of dangerous conditions at the dam months before it collapsed.
The failed dam was built in 1976 using the “upstream” dam construction method, which is the riskiest method of dam construction. This design involves piling waste from the mine toward the tailings pond, raising the dam to new levels as the dam grows in size. Upstream dam construction is the cheapest design and also the most prone to failure, according to experts. About 76% of tailings dam failures worldwide are related to upstream construction methods. The same design for storing mine waste is now being proposed for the Back Forty’s tailings dam next to the Menominee River.
Aquila’s ad never mentions the Brazilian disaster or that the government of Brazil has banned the use of this design from further use and ordered the dismantling of 88 existing upstream tailings dams.
What are tailings dams?
Tailings dams are some of the largest human-made structures on earth. Tailings are the waste material left over from the crushing, grinding and chemical (including cyanide processing of mineral ores. Tailings often contain residual minerals – including lead, mercury and arsenic that can be toxic if released to the environment. However, unlike water-retaining dams made of concrete and steel, tailings dams are held back by walls of sand and silt.
Aquila’s ad misrepresents the facts
Aquila’s ad states that their tailings dam “is neither a pond nor does it store liquid tailings.” The ad is wrong on both counts. According to Aquila’s own permit, the Back Forty tailings dam WILL contain a pond. And there WILL be liquid tailings. The permit is absolutely clear on this point: wet tailings will be deposited in the Tailings Management Facility (TMF) and will be topped by a huge pond consisting of water from the tailings. In Aquila’s dam safety permit, the volume of “supernatant water” (floating on the surface of the tailings) is estimated at almost 40 million gallons.
Aquila’s TMF does not follow industry best practice for dam safety
Contrary to Aquila’s claim that the tailings from the Back Forty processing plant will resemble “thick drywall mud,” the tailings will be 19 percent water when they are pumped into the TMF. The industry best practice is for tailings to be thoroughly dewatered and stored in “dry stacks” with a lower moisture content, according to an expert review panel that investigated the 2014 Mount Polley tailings dam failure in British Columbia, Canada. Mount Polley was the largest environmental disaster in Canada’s mining history.
Using tailings with relatively high moisture content to save costs increases the risk that tailings will liquefy and cause the tailings dam to fail. If Aquila was truly concerned with minimizing the known risks of upstream tailings dams they would have chosen the dry stack option.
Aquila will use waste rock, rather than tailings, to construct the perimeter wall of the TMF
Aquila’s ad attempts to contrast the traditional design that uses tailings to construct the perimeter wall of the TMF with the company’s plan to use more stable waste rock for the wall. However, Aquila has acknowledged in its mine permit application that most of the waste rock is expected to be acid-generating. The U.S. Environmental Protection Agency has determined that potentially acid-generating waste rock is not suitable for tailings wall construction because it is not chemically stable.
Permanent Waste Storage?
Aquila says that tailings facilities are permanent structures that remain after mining ends. But how “permanent” are these structures? According to Dr. David Chambers, an international expert on tailings dam safety, in the last ten years, “the failure rate of tailings dams has remained at roughly one failure every 8 months (i.e. three failures every two years). Over a 10,000 year lifespan (a conservative estimate for how long these structures will need to maintain integrity) this implies a significant and disproportionate chance of failure for a tailings dam.”
According to Kathleen Heideman of the Mining Action Group of the Upper Peninsula Environmental Coalition, “Instead of talking about 100 year rainfall events, we need to be thinking about a 10,000-year lifespan. What are the real storm risks, the real seismic risks, the groundwater risks from failure of materials with a limited life, like plastic liners underneath of TMF?”
Aquila’s TMF ad is inaccurate and misleading mine speak
In response to well-founded public concerns about the safety of tailings dams and the track record of the upstream tailings dam design, Aquila has made false and misleading claims about its proposed tailings dam next to the Menominee River. Aquila’s claims in a paid ad and in a mailing to Menominee County residents, are not consistent with their own mine permit application and with the scientific literature on tailings dam construction.
“The biggest environmental disaster threat related to mining”
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 http://www.grida.no/publications/383).
Michigan’s Department of Environmental Quality May Hold a Public Hearing
In response to public demands for a consolidated public hearing on Aquila’s air use permit and the dam safety permit, the DEQ is currently evaluating the possibility of a hearing when Aquila has submitted all of the information on these permit applications.
The Coalition to SAVE the Menominee River Needs Your Support
The Coalition to SAVE the Menominee River has taken a leadership role in bringing together a diverse group of concerned citizens, environmental organizations, sportfishing groups, faith organizations and tribal water protectors to educate and organize people about the dangers of open-pit metallic sulfide mining.
The Coalition has filed a petition for a contested case hearing in the state of Michigan, challenging the Michigan DEQ’s decision to grant the wetland permit. They have also filed legal action in federal court. One of their expert witnesses is Dr. David Chambers, an international expert on tailings dam failures and the president of the Center for Science in Public Participation. These efforts are both necessary and expensive to protect our precious waters and communities.
The Coalition will have a spring forum/fundraiser on Sunday, May 5, 2019 at the Embers, 1871 Co. Rd. B in Peshtigo, WI from 1:00-6:00 pm. Mark Doremus will show his documentary on the mine controversy and Dave Blouin from the Wisconsin Sierra Club and I will be speaking.
Please use the enclosed envelope to send a tax-deductible donation to support these efforts.
Stay tuned,
Al Gedicks, Executive Secretary