Designed to Fail

Posted on February 21, 2019 by Save the Wild UP

“Back Forty Tailings Facility ‘Not a Pond,’ Aquila Says”?

Response by the Mining Action Group

The Aquila Back Forty’s Mining Permit amendment, under consideration by the Michigan Department of Environmental Quality, features a tailings dam (aka “tailings management facility”, or TMF) to be built using the extremely risky “upstream” method. Objections to the Back Forty’s TMF design have been raised by numerous environmental groups, including the Mining Action Group of the Upper Peninsula Environmental Coalition, Menominee River Front 40, the Coalition to Save the Menominee River, the Center for Science in Public Participation, the Wisconsin Resource Protection Council, the Michigan Environmental Council, and others.

The upstream tailings dam method is designed to fail, environmental groups warn. Industry experts consider the upstream method to be the least desirable type of tailings dam construction, due to its high risk of dam instability.

It is used because it is cheaper to construct, but is not the “Best Available Technology”. TMF dam walls are “raised” and each successive raise is partially supported by tailings, as depicted in the Back Forty TMF diagram above. This design is fundamentally unstable, and part of what makes the “upstream” construction method especially risky. The upstream dam method has been banned in several countries.

A POND IS NOT A POND, SAYS AQUILA?

Aquila’s public relations manager, Dan Blondeau, is trying to assure concerned citizens that the Back Forty’s upstream tailings dam won’t fail. In correspondence with filmmaker Mark Doremus, Blondeau claimed the “Back Forty tailings facility is NOT a pond and will NOT store liquid tailings.”

“I’d say Blondeau should read the permits,” said Kathleen Heideman of the Mining Action Group.

“The Back Forty tailings WILL be pumped as a wet slurry. These WILL be liquid tailings,” said Heideman. “The Back Forty tailings facility WILL contain a pond.”

The permit amendment makes it clear that wet tailings, deposited in the TMF structure, will be topped by a huge pond – water from the tailings:

“The decant pond expands from 100,000 cubic meters (m3) capacity to a maximum of 150,000 m3, then diminishes to 50,000 m3 at the end of operations”
“The height of the decant pond will rise as the TMF is constructed, with a maximum height of 36 meters at full build-out”

It may be hard to visualize the size of that pond, but “150,000 m3” (cubic meters) means the decant pond will be roughly six times larger than the Lincoln Memorial Reflecting Pool in Washington DC. [1]

In the Aquila Back Forty Dam Safety Permit, the volume of “supernatant water” (floating on the surface of tailings) is predicted to be even larger – almost 40 million gallons:

“The maximum volume of supernatant water allowed in the (tailings) decant area will decrease with time from 0.15 Mm3 (39.6 Mgal) to 0.05 Mm3 (13.2 Mgal)”

40 million gallons of water – how big is that?

“A good-sized bath holds 50 gallons, so a million gallons would be 20,000 baths” [2]
The Back Forty TDF pond will hold enough water to fill 800,000 baths.
“An Olympic-sized swimming pool holds 660,000 gallons of water” [3]
The Back Forty TDF pond will hold enough water to fill 60 Olympic swimming pools.

Blondeau claimed the Back Forty tailings dam has a “maximum projected height of 130 feet” but the permit states a maximum projected height at closure of “42 meters” (138 feet tall). How tall?

A mature white pine tree averages 50 to 80 feet tall.
At 138 feet, the Back Forty tailings dam will be 55% taller than Marquette’s Landmark Inn (89 feet tall).

WILL ADDITIONAL TAILINGS STORAGE BE NEEDED?

The Back Forty tailings facility will cover 124 acres of the mine site.

“Blondeau fails to acknowledge the monstrous size of the Back Forty tailings dam,” said Heideman. “124 acres of tailings – that’s like 50 city blocks, or 100 football fields. Tailings will cover an area 25 times larger than the Superior Dome at Northern Michigan University,” said Heideman.

And that may be just the beginning. The Mining Action Group has questioned whether Aquila is being honest in calling the Back Forty project a “7 year open pit mine” operation. Environmentalists believe that Aquila is planning an underground mining phase, although the permit applications deny that any underground mining will take place.

From 2015 until early 2018, Aquila Resources described the Back Forty project as having a “16 year life of mine and mill of 16.1 Mt of ore, including both open pit and underground mining.” This claim was repeated in Aquila’s press releases, investor statements, in presentations to the local community, and in correspondence with the Michigan DNR and the Menominee Indian Tribe of Wisconsin. In 2016, Aquila told their investors they would submit an underground permit once the open pit mine and milling facility were operating. Now the applicant is winking, telling investors that underground expansion will require “additional studies…”

Environmental groups claim that Aquila will pursue additional 9 years of underground mining, for a total of 16 years of mining. If true, the TMF will need to “accommodate” additional waste.

That’s the reason why mining companies build “upstream” tailings dams – the structure can “grow higher” if the mine needs to store more waste. TMF impoundments are frequently expanded through additional raises, which greatly increases the height of the dam walls and the total volume of waste rock and water contained within the structure. This habit of incremental raising greatly exacerbates the problem of instability, and has resulted in the catastrophic collapse of several tailings dams.

Strict impoundment loading limits were not defined in the Back Forty mine permit amendment application. It is reasonable and foreseeable to assume that Aquila has selected the controversial “upstream dam” method because it could allow for sequential expansion through raising of the dam wall (as pictured above) What may begin as a TMF with “three raises” can grow exponentially via incremental change, if permitting review is not environmentally protective. The tailings dams at Brumadinho and Mount Polley were raised higher than originally designed, multiple times.

PERMANENT WASTE STORAGE

“Instead of talking about 100 year rainfall events, we need to be thinking about a 10,000-year lifespan,” said Heideman. “What are the real storm risks, the real seismic risks, the groundwater risks from failure of materials with a limited life, like the plastic liners underneath the TMF?”

When the risks are properly calculated for a 10,000-year lifetime – the figure often used for how long these tailings structures will need to maintain their integrity – experts say there is “a significant and disproportionate chance of failure for a tailings dam.” [4]

“TRIED, TESTED, AND PROVEN”?

Blondeau claims that the design of the Back Forty TMF “uses tried, tested, and proven engineering methods” because “similar facilities are already in operation at the Malartic Mine and the MusselWhite Mine in Canada, and the Neves Corvo Mine in Portugal.”

These mines – Malartic, Musselwhite, and Neves Corvo – offer proof of nothing. “Thickened tailings” have been used for less than 10 years. The type of ore, tailings, and method of disposal varies widely – and the TMF designs are very different:

Malartic Mine

The Malartic Mine has only been operating since 2011. Malartic’s tailings are non-reactive. The thickened tailings have “solid material concentrations of between 65 and 70%” with “little or no free water. They form cone-shaped cells of various heights. The tailings are used to “cover acid-generating tailings” (to a depth of 3 meters), to remediate a previously abandoned tailings impoundment. To “avoid overflows, a sterile stone wall will be built around the various cells.” This is significantly different from the Back Forty TDF, where tailings will be highly reactive, tailings will decant a large quantity of water, and TMF walls will be built using reactive waste rock, not “sterile stone.” [5]

Musselwhite Mine

The Musselwhite Mine in Northwestern Ontario went into production in 1997 and “began thickened tailings disposal in May 2010.” “The cold climate presents a special challenge to operating the thickened tailings system as there is very little precedent experience.” To reduce the likelihood of acid generating and metals leaching in the long term, the Musselwhite Mine announced plans “to remove the sulphide minerals from the tailings stream using a flotation plant.” Construction of a tailings thickener began in 2009; this was done to “to allow for an increased life span (capacity) of the current tailings management area. The thickener will reduce the water content in the tailings to approximately 74% solids to allow for stacking/mounding of the dry tailings…” [6] This is significantly different from the Back Forty TDF, where tailings are highly reactive, sulfides are not removed, and tailings are not “dry” or “stacked.” [7]

Neves Corvo Mine in Portugal

Owned by Lundin Mining, the Neves Corvo Mine opened in 1988. “Neves-Corvo has been developed as an underground operation, exploiting a number of polymetallic sulphide orebodies” with“tailings from the mine stored into a 190 hectare tailings management facility (“TMF”) bounded to the north by a rockfill embankment across a natural river valley. The facility was originally developed for subaqueous tailings deposition, but converted to thickened tailings deposition in 2010 “with an accompanying thickened tailings plant to increase the storage capacity.” At Neves Corvo, due to “multiple expansions of underground mining” and “expansion of the zinc processing plant and the volume of tailings produced, there will also be a need to expand the tailings thickening plant.” Additionally, underground “voids are being backfilled using a mixture of development rock, cement, and “paste fill (PF) made from cycloned process tailings.” This is different from the Back Forty TDF: Neves Corvo uses an upstream tailings dam [8] but the disposal of thickened tailings (begun in 2010) has not solved their tailings storage problems: new mining and “expansion of the zinc processing plant” resulted in yet more tailings; a new “Feasibility study for expanding the TMF… will provide a comprehensive tailing development scenario.”

Read that again: after 30 years of mining, Lundin is still trying to come up with a “comprehensive tailing development scenario” for Neves Corvo Mine? Ever-expanding operations come with demands “for additional tailings and mine waste rock storage at the Neves Corvo tailings storage facility, beyond the 2015 deposition design. Specifically an increase of up to 27 Mt of tailings and as much as 10 Mt of mine waste rock need to be accommodated…” [9]

That’s exactly what must be avoided at the Back Forty.

In all these mines, “thickened” tailings management was used to address “capacity problems” caused by expanding mining operations – suggesting these mines were not carefully planned, or failed to disclose future mining phases, resulting in undersized tailings storage. Mining companies treat TMFs like magic garbage bins, which must expand on demand to “accommodate” whatever amount of tailings and waste is produced.

FILLED WITH REACTIVE WASTE

The Back Forty is a polymetallic orebody. After processing, the finely ground tailings will contain hazardous metals cable of producing acid mine drainage and mobilizing metals through leaching. Geochemical modeling provided in Aquila’s 2015 application demonstrated that 77% of the waste rock and nearly all ore is reactive. The leachate produced by geochemical analysis of Back Forty tailing samples had an average pH of 2.5, very acidic.

All tailings held inside the TMF will be reactive, at risk of acid mine drainage. Recent tailings dam collapses, like the Brumadinho tailings dam in Brazil and the Mount Polley tailings dam in Canada, resulted in catastrophic environmental damages but their tailings were either inert or less reactive.

Blondeau downplayed the hazardous nature of the Back Forty tailings, comparing them to “toothpaste” and “drywall mud.”

In fact, the Back Forty’s tailings will be more toxic than either Brumadinho or Mount Polley.

“Mr. Blondeau’s comparison of the consistency of the dewatered tailings to ‘drywall mud’ or ‘toothpaste’ is not reassuring when you consider that with the ‘upstream’ design these mudlike materials end up being a structural part of the dam!” said Steve Garske of the Mining Action Group. “The remaining water in the tailings is what causes these dams to fail.”

Heideman calls the comparison with drywall mud and toothpaste “insulting.”

“There is no beneficial reuse. There is nothing domestic or healthy about it. These are toxic industrial tailings, full of mercury, lead, cancer-causing metals, acid-generating sulfides, residual sodium cyanide, chemical frothing reagents used in the milling process, and more. Failure of the Back Forty’s upstream tailings dam, whether it happens in five years or five hundred, would be an unspeakable environmental catastrophe.”

DESIGNED TO FAIL

Upstream mine tailings dams have been called “bombs waiting to explode” – and they are collapsing. The “failure rate of tailings dams has remained at roughly one failure every eight months… Over a 10,000-year lifespan (a figure often used for how long these structures will need to maintain their integrity) this implies a significant and disproportionate chance of failure for a tailings dam.” [10]

“This is really the mining industry’s dirty secret: upstream tailings dams are cheap, risky, and unstable,” said Heideman. “The State of Michigan cannot allow the Back Forty project to proceed as designed.”

NOTES

New Report Finds Fault with Sulfide Mine’s Plans

Posted on February 12, 2019 by Save the Wild UP

MARQUETTE, MI — A new technical report from the Center for Science in Public Participation (CSP2) identifies serious faults with Aquila Resources’ Back Forty Mine Permit Amendment application, now under review by the Michigan Department of Environmental Quality.

The technical review of the Back Forty permit was conducted by Dr. Kendra Zamzow, an environmental geochemist, and Dr. David Chambers, an internationally-known expert on tailings dam safety. CSP2 analyzes mining applications in order to “provide objective research and technical advice to people impacted by mining.”

The Back Forty project proposes to excavate an 800 foot deep open-pit sulfide mine on the banks of the Menominee River, 100 feet from the water. Milling will also take place on-site, using cyanide leaching, mercury recovery, and flotation. Aquila claims to be “minimizing impacts” but the footprint of the facility has ballooned to 440 hectares (1087 acres), largely due to a larger tailings management facility. Most of the mine site would be covered by waste rock, ore storage, milling facilities and tailings storage. Environmental groups claim that the Back Forty’s environmental impacts could be significantly reduced by using feasible, common-sense alternatives — but Aquila has rejected these options.

Nearly all of the Back Forty rock is reactive – capable of producing Acid Mine Drainage (AMD) when exposed to air and water. AMD pollution devastates watersheds and lasts hundreds of years. Tailings and waste rock will be stored on-site during mining, and the tailings will remain on the surface forever. Aquila has told their investors they will pursue underground mining as a “second phase” of operations, but this is not acknowledged in any permit. Underground mining could extend the mine’s life from 7 years to 16 years, greatly magnifying the risks. During closure, the open pit will be backfilled with waste and tailings. Once this takes place, groundwater contaminated with AMD is predicted to seep into the river.

CSP2’s technical report evaluated the Back Forty mining permit, including updated environmental impacts, feasible alternative designs, financial assurances, and Aquila’s proposed use of an “upstream” tailings design, the same risky construction method that has resulted in catastrophic tailings dam failures around the world.

Key Findings of CSP2’s Technical Report

The Tailings Management Facility (TMF) is to be constructed using the upstream dam construction method, which is the least safe design. It also applies an underestimated seismic event to the construction design.
There are no details for the wastewater treatment plant (WWTP).
There is no information on how mercury from the retort will be stored or transported, or whether there is a facility to receive it.
Mercury emissions from the retort did not go into air deposition modeling.
Air deposition modeling suggests that Spring Lake currently meets mercury water quality standards, but will exceed (violate) them after mining begins. By using old data, Aquila Resources may be biasing the baseline high, underestimating the impact of emissions.
There are significant unexplained inconsistencies with the volume of chemical reagents, and the storage capacity for lime.
Recent data suggests upper groundwater layers flow faster than the data used in the groundwater model. The groundwater model was not updated, and may underestimate the volume of dewatering and impacts to wetlands.
Biological monitoring should include mussels, but currently that is not scheduled.
There are no plans to monitor surface water for metal concentrations, although sediment and mine discharge will be monitored for metals. Surface water metal analysis should be added.
Financial assurance is underestimated.

“This report only underscores the fact that the original Mining Permit should not have been granted,” said Ron Henriksen, spokesperson for the Front 40, which helped secure the review. “Aquila continues to provide inadequate applications with missing information. The DEQ should rescind this entire permit, have the applicant revise their mistakes, and refile it, properly formatted, with all material in one complete, organized application package.”

“These flawed permits and their environmental impacts are deeply interconnected. We urge the State of Michigan to hold a consolidated hearing on the Mine Permit Amendment, the Air Permit application, and the Dam Safety Permit application – an option allowed under Part 632 in cases where an applicant applies for multiple permits,” said Kathleen Heideman, a member of the Mining Action Group of the Upper Peninsula Environmental Group (UPEC).

“We need a thoughtful, consolidated hearing to discuss these permits,” said Heideman. “Nothing less than the future of the Menominee River is at stake.”

“The mine permitting process generates thousands of pages of data and arguments and choices. What is a grassroots environmental organization to make of it? Our logical minds can see where the loose ends are dangling. By hiring mining experts ourselves, we can identify those loose ends as areas of serious concern about this mining permit. We can enter the discussion that would otherwise be dominated by agency staff, lawyers, and mining company engineers. Expert commentary gives us a louder and more credible voice,” said Jon Saari, a board member of the Upper Peninsula Environmental Coalition.

“CSP2’s expert review of Aquila Resources’ latest Back Forty mining permit application has exposed serious flaws in their mining layout and operational design. This includes their insistence on using the risky upstream dam construction for their tailings facility,” said Steve Garske, a member of the Mining Action Group of the Upper Peninsula Environmental Coalition. “If constructed as planned, this mine will literally be an accident waiting to happen.”

Technical review of the Back Forty Mine Permit Amendment was made possible by a collaborative effort of the Mining Action Group, the Front 40 Environmental Fight, the Coalition to Save the Menominee River, a 2019 grant from Freshwater Future’s Great Lakes Network, and a 2019 emergency mini-grant from the Western Mining Action Network.

Public Participation

The deadline for submitting written comments on the Aquila Back Forty Mine Permit Amendment permit has been extended until February 15, 2019 at 5pm (EST). Mail comments to Back Forty Mining Permit Amendment, MDEQ-OGMD, 1504 West Washington Street, Marquette, MI 49855, or email comments to DEQ-Mining-Comments@michigan.gov with “Back Forty Mining Permit Amendment” as the subject.

Learn More

Download CSP2’s Technical Review of the Back Forty MPAA: http://bit.ly/BackFortyCSP2-2019
Review permit files: Aquila Back Forty Mine Permit Amendment and EIA
Submit written comments: DEQ-Mining-Comments@michigan.gov
Learn more about Center for Science in Public Participation

More Red Flags for Aquila: Enviro Groups Fund NEW Technical Review of Back Forty Sulfide Mine

Posted on January 16, 2019 by Save the Wild UP

FOR IMMEDIATE RELEASE — JOINT PRESS STATEMENT

STEPHENSON, MI — The Front 40 Environmental Group and the Mining Action Group (MAG) of the Upper Peninsula Environmental Coalition (UPEC) have secured a new independent technical review of the Aquila Back Forty Mine Permit Amendment application, to be completed by the Center for Science in Public Participation (CSP2). CSP2 analyzes mining applications in order to provide objective research and technical advice to people impacted by mining. Dr. Kendra Zamzow and Dr. David Chambers are conducting the review.

The Back Forty project proposes to excavate an 800’ deep open-pit sulfide mine on the banks of the Menominee River, 100’ from the water. Milling will take place on-site, using cyanide leaching and flotation. Most of the mine site will be covered by waste rock, ore storage areas, milling facilities and tailings storage. Aquila claims to be “minimizing impacts” but the footprint of the facility has ballooned to 440 hectares (1087 acres), largely due to a larger tailings management facility. Environmental groups claim that the Back Forty’s environmental impacts could be significantly reduced by using common-sense feasible alternatives — but Aquila Resources has rejected these options.

Nearly all of the Back Forty rock is reactive, or capable of producing Acid Mine Drainage (AMD) when exposed to air and water. AMD pollution devastates watersheds, and lasts hundreds of years. Tailings and waste rock will be stored on-site during mining, and the tailings will remain on the surface forever. Aquila has told their investors they will pursue underground mining as a “second phase” of operations, but this is not acknowledged in any permit. Underground mining would extend the mine’s life from 7 years to 16 years, greatly magnifying risks. During closure, the open pit will be backfilled with waste and tailings; as a result, AMD groundwater contamination is predicted to seep into the river.

CSP2’s review will consider changes to the Back Forty mining permit, including environmental impacts, feasible alternative designs for waste storage, transportation plans, remediation, financial assurances, and the proposed use of an “upstream” tailings design, a risky construction method that has resulted in catastrophic tailings impoundment failures. Dr. Chambers, an internationally-known expert on tailing basins, will review this aspect of the permit.

“The Back Forty mine will threaten freshwater resources and destroy important cultural resources belonging to the Menominee Indian Tribe of Wisconsin,” said Kathleen Heideman, a board member of the Upper Peninsula Environmental Coalition.

More than 120 concerned citizens, tribal members, environmental groups and others participated in the recent Michigan Department of Environmental Quality’s (MDEQ) public meeting, held on January 9th in Stephenson, MI. Many speakers expressed frustration over access to the permit files, including password errors, server problems,and browser or operating system incompatibilities. In light of these problems, the MDEQ has been asked to grant a 30-day Extension of the Public Comment Deadline.

The Mining Action Group also requested a consolidated hearing process in order to discuss the Back Forty Mining Permit Amendment request, a modified Air Quality permit application, and a new Dam Safety permit application. “We need a thoughtful, consolidated hearing that will allow concerned citizens to discuss all of these interconnected permits,” said Heideman.

Technical review of the Back Forty Mine Permit Amendment is made possible by a collaborative effort of the Mining Action Group, the Front 40 Environmental Fight, the Coalition to Save the Menominee River, a 2019 grant from Freshwater Future’s Great Lakes Network, and a 2019 emergency mini-grant from the Western Mining Action Network.

PUBLIC PARTICIPATION

Comments on the Aquila Back Forty permit will be accepted until February 6th at 5pm (EST). Mail comments to Back Forty Mining Permit Amendment, MDEQ-OGMD, 1504 West Washington Street, Marquette, MI 49855, or email comments to DEQ-Mining-Comments@michigan.gov with “Back Forty Mining Permit Amendment” as the subject.

The MDEQ has been asked to extend the Public Comment deadline, but no decision has been announced. Please contact Melanie Humphrey for an update on the extension request: 906-250-7564, HUMPHREYM@michigan.gov

Instructions for reviewing the Back Forty permit materials were included in the MDEQ’s Public Notice: https://www.michigan.gov/documents/deq/deq-ogmd-mining-Back_Forty_mine_amendment-PublicMeetingNotice_1.9.2019_641172_7.pdf

Mission of the Mining Action Group
The UPEC Mining Action Group (MAG), formerly known as Save the Wild U.P., is a grassroots effort to defend the clean water and wild places of Michigan’s Upper Peninsula from the dangers of sulfide mining. Contact the Mining Action Group at info@savethewildup.org or call (906) 662-9987. Learn more about the UPEC Mining Action Group at miningactiongroup.org.

Mission of the Front 40 Environmental Fight
The Front 40 is a grassroots organization that was formed in early 2003 in response to the threat of a metallic mineral mine potentially being developed on the shores of the Menominee River in Lake Township, Michigan. It is the principal objective of the Front 40 Environmental Group to ensure that metallic sulfide mining operations are not allowed to adversely impact our rivers, lakes, groundwater and lands. Learn more about the Front 40 group: menomineeriver.com.

Mining Action Group

The Mining Action Group is a volunteer, grassroots effort to defend the clean water and wild places of Michigan’s Upper Peninsula from the dangers of sulfide mining – previously known as Save the Wild U.P.

Tag Archives: environmental impacts