Tag Archives: air

Air filtration necessary on Eagle Mine air stack to keep air clean

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My name is Kathleen Heideman, and I’m commenting tonight as a Marquette resident and tax payer, and as a Michigan citizen concerned about environmental quality. I’m also speaking on behalf of my family, which is an adjacent landowner to Rio Tinto’s Kennecott Eagle Mine site. When Rio Tinto says they want to be a “good neighbor,” they’re talking about being our neighbor.

Rio Tinto promised us a world-class mine with state-of-the-art environmental protections. The Bag House air-filter system they pledged to install was an environmental protection. According to Cynthia Pryor:

“This 65-foot-tall high stack sits within 150 feet of the Salmon Trout River. We worked hard to get the air filter included as part of Kennecott’s original air quality permit as they intended the mine exhaust to be vented directly to the air. Now, they are backpedaling and want this air filter to be removed. We are vehemently opposed to such a notion and want to make this clear…”

Let me be clear: Rio Tinto’s request to remove the air filter from their Main Vent Air Raise (MVAR) is based entirely on finances, with blatant disregard for environmental quality. It hasn’t been a good year for Rio Tinto. Perhaps tonight’s hearing should be called a “profit maximizing” permit review.

Rio Tinto wants us to believe their air filter is no longer necessary, due to changes underground, or that it would simply not be compatible with their special sort of mine. Actually, Rio Tinto wants to break this promise because air filter systems are notoriously difficult and costly to maintain. Regardless of the source or size of the emission particulates, emissions will build up on the filter, just as lint accumulates on a dryer screen, or dirt coats the air filter of a truck. Instead of discarding the filter, the bag house (depending on design) must shake, blow or electrostatically discharge the material that builds up on the filter, collecting this “caked” debris for proper treatment as a pollutant. This is a nasty cake, containing heavy metals from exhaust and sulfur-rich ore dust. Air filters fail when they develop tears in their fabric (allowing pollutants to stream through unchecked), or when moist material accumulates on the filter (reducing filter efficacy or blocking exhaust flow) or when acidic compounds in the emissions attack the filter fabric. While difficult to maintain, the whole point of installing an air filter and bag house is Process Control: avoid sending this stuff out into the environment, period.

According to their permit modification request, a mine worker will now simply stand near the MVAR stack once a day, and make a visual “observation” recording whether emissions other than water vapor from the stack are VISIBLE on a gray-scale (limit of 5% opacity). Seriously? This is an unacceptably primitive “alternative” to an air filter system.

It must be noted that Rio Tinto’s Eagle Mine proposes to have a below-ground heating system functioning most of the days per year, Spring – Fall – and Winter, whenever the outside air temperature falls below 32°. Conveniently, their heater is considered “exempt” for purposes of emissions control, so we are supposed to disregard all the hydrocarbon pollutants present in their heater emissions (which also exit the MVAR stack). In fact, the mine is proposing to increase the amount of underground heating, increasing the BTU output (and emissions) of the heaters. This mine will be heated 24-7, most of the year. Air exhausted from this mine will contain vehicle exhaust from underground mining vehicles, emissions from the heating system, and clouds of ore dust particulates released through blasting, loading, and hauling — and on most days of the year, exhausted air will be warmer than ambient air temperature. Warm, moist air — from a damp mine!

Rio Tinto had to have known from the beginning there would be condensation issues for the MVAR filter they were proposing. Any other conclusion doesn’t make sense. Condensation is a common problem, which the air filter industry routinely handles by recommending insulation and heating of the air filter bag house. Again, this increases total cost of operation. Condensation issues reduce the effective life of the air filter, whatever filter fabric is selected, which again makes the air filtration system more expensive to maintain. Added to this situation is the fact that ore dust will be sulfide-rich, creating (sulfuric) acid condensate on the air filter (as well as the MVAR and bag house equipment), leading to yet more expensive maintenance.

Clearly, Rio Tinto’s proposal to remove air filter controls from the MVAR is a  cost control decision, not a pollution-control or process-control decision.

Sending an unfiltered plume of high velocity mine exhaust directly into the clean air over the Yellow Dog Plains is unconscionable. Notwithstanding the peaks of the Huron Mountains, the Yellow Dog Plains are the height of land for Marquette County. There has never been heavy industry in this location, but according to Rio Tinto’s air pollution dispersal maps (based on dubious weather models unconnected to the Yellow Dog Plains), mine pollution will soon be raining down over half of Marquette County. The unfiltered particulates they propose to send into our skies will be blanketing the blueberries we harvest, changing the PH of our lichen-covered soils (destroying these lichen, which are highly sensitive to acid rain), damaging the ecosystems of the Huron Mountains and Silver Lake Basin, accumulating in the watersheds of the Salmon Trout River, Yellow Dog River and countless wild streams, and contaminating our air with particulates that present an inhalation hazard for humans and wildlife. Rio Tinto may plan on issuing dust masks to employees at the mine, but they certainly won’t be handing them out to deer hunters, berry pickers, the deer and moose and wolves, or anyone with camps on the Yellow Dog, or homes in the Big Bay area. We all deserve clean air to breathe.

It is curious to note: Rio Tinto states in their Permit that they may need to change underground operations to respond to economic considerations, which are “constantly changing”:

“The underground ore handling system is based upon “best facility economics. Because economics are constantly changing due to market conditions, changes to the underground ore handling system may be necessary to reflect future market conditions.”

Of course, another factor that is “constantly changing” is industrial technology and the best facility practices related to process control and air pollution abatement measures! Curiously, the permit makes no mention of changing practices to align with future environmental practices.

Rather than use a filter system, Rio Tinto proposes to spray water inside the mine. Spraying groundwater on air-polluting dust? That’s a 19th century bandage, not a pollution control. Rio Tinto’s “solution” to air pollution assumes that Michigan groundwater is endlessly available, free for the taking, and unconnected to aquifers supplying drinking water to surrounding residents of Marquette County. Those assumptions are unacceptable.

Rio Tinto repeatedly promised to build a world-class mine, using world-class technology, and world-class safety practices. Was that a bait and switch strategy? If they made an empty promise, regarding their MVAR air filter, the Eagle Mine permit was fraudulent.

If allowed, Rio Tinto’s permit modification would allow the mine to spew an unfiltered plume of air pollution for the winds to disperse over Marquette County. The “Solution to Pollution is not Dilution” – that was 19th century approach. Rio Tinto received a mine permit from the DEQ because of environmental assurances they made, including the MVAR’s filter.

They do not have free license to pollute Michigan’s air and water. Please deny this permit modification on the grounds that it is based on economic considerations and terrible science, and will functionally increase both air and water pollution.

While the air filtration system Rio Tinto proposed will be expensive to implement and difficult to maintain, such control measures are essential, not optional. Clean air is priceless.

Kathleen M. Heideman
Marquette MI 49855

Analysis: Rio Tinto’s Permit Modifications

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By Cynthia Pryor

The main and substantive issue, in the new Air Quality permit application for the Rio Tinto Eagle Mine, is Rio Tinto’s assertions that an air emission control is not required for the Main Air Raise Vent (MVAR). The MVAR is a stack that is 128″ (10.6′) in diameter and 65′ high and is the only vent for all the underground workings for the mine. The emissions will include all those items associated with the development and retrieval of the ore body including blasting, ore handling, truck traffic, diesel fuels, large mine heaters, etc. Rio’s original Air Quality Permit was approved with the inclusion of a Bag House and air filter on this MVAR stack – that would capture 99% of all emissions which would include reactive sulfides resident in and broken loose from this ultramafic massive sulfide ore body.

Rio Tinto has reconfigured their plant so that they have moved the original underground cement batch plant and associated material silos (aggregate, cement) to the surface near Eagle Rock. They say there will be no crushing underground and an ore pass system will not be utilized – therefore reducing sulfide dust and emissions to such a low level that a bag house would no longer be required. In fact they say that a bag house would not even function properly – the emissions are so low. They will instead control all underground dust with water spray from a tank truck and and a hose.

All of Rio’s assumptions are based on modeling programs, heater systems whose emissions are exempt from regulation, and the assertion that will be able to control all dust with water spray from a hose. The DEQ does not require them to have controls on this huge MVAR stack, even though there will be controls on every other emission source at the mine, including an emergency generator. The DEQ does not require any air quality monitoring of the site or of this stack. Emission testing of the stack will only take place when Rio Tinto is producing 1,660 tons of ore a day. The DEQ will not require any emission testing during the blasting of adits or production of ore under this tonnage rate. Sulfide, heavy metals, blasting emissions, fuel emissions, etc. will be free flowing into the air on the Yellow Dog Plains with no control, no monitoring, and very limited testing.

The DEQ calls the Yellow Dog Plains an attainment area – which is a geographic area which has air quality below Federal Air Quality Standards. In other words, the air is good on the Plains and Rio has now the ability, under law, to pollute this air until they reach the limit of the air quality standard set by the EPA. Their models show that they can do this at 91% of the attainment level. That leaves 9% left for someone else to pollute to get them at a Saginaw, Detroit Chicago level of Air Quality. These emissions are only representative of the mine area itself. All diesel emmisons and fugitive dust from the transportation of the ore on public roads are not included in this emission standard calculation. The DEQ says they have no regulatory oversight of public roads. Nor do they have oversight of the underground workings to prove they can make their claims of low emissions. That is someone else who takes care of that (Mine Safety and Health – MSHA) . The DEQ is only concerned with what comes out of the stack and Rio’s models say they can do it and that is all the proof they need until they do their first production emissions test.

From the beginning, the State of Michigan has recognized that non-ferrous sulfide mining is different and that sulfides, from metallic sulfide mines, released into the environment and coming into contact with air and water can cause Acid Mine Drainage and damage to our land, our waters and our communities. The DEQ Air Quality staff do not seem to see any danger to the Salmon Trout River which flows a mere 150′ from this stack. They have required no impact assessment of the Yellow Dog watershed, nor an impact statement to Eagle Rock – the KBIC sacred site within the fence of this mine. They see no danger to the community of Big Bay and it’s peoples, lake and streams who are an immediate few miles downwind from the Eagle Mine.

Our job is to ask for proof that their models are correct – by demanding air quality monitors at the site that run 24/7 for the life of the mine.
We must also demand that Rio Tinto keep the promise that they made in their original permit (made as a result of public comment and pressure!) to put an air filter on the main polluting source at the site – the MVAR stack. “PROMISES KEPT” is Rio Tinto’s main motto. Let us make them hold to that promise.

 

DEQ details mine air quality hearing

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MARQUETTE – Michigan Department of Environmental Quality officials have released details on an upcoming air quality permit public hearing and comment period for Rio Tinto’s Eagle Mine project.

The mining company has made several changes on-site since its original air use permit application was approved in 2007. Some of the modifications listed by the DEQ included eliminating on-site ore crushing, adding an enclosed aggregate storage building and eliminating a fabric filter dust collector.

An informational session and public hearing have been scheduled for March 12 in the Huron Room of the University Center at Northern Michigan University. The information period will be from 5 p.m. to 6:30 p.m. DEQ staff will be available to answer questions. The public hearing will begin at 7 p.m.

The Eagle Mine site north of the city of Marquette in Powell Township is seen in this recent aerial photo. (Rio Tinto photo)

“The sole purpose of the hearing will be to take formal testimony on the record,” the DEQ said in its hearing announcement. “During testimony, questions will not be answered; however, staff will be available to answer questions outside the hearing room.”

A written public comment period is in effect on the draft permit conditions, which is required by state and federal regulations.

Written comments received during the comment period will be considered in the final permit decision.

Mail comments by March 12 to: Mary Ann Dolehanty, Permit Section Supervisor, Michigan DEQ, Air Quality Division, P.O. Box 30260, Lansing, MI, 48909-7760. Comments may also be submitted from the web page: www.deq.state.mi.us/aps/cwerp.shtml. (click on “Submit Comment” under the Rio Tinto Eagle Mine LLC, Permit to Install No. 50-06B listing).

After resolving any issues raised during the public comment period and the hearing, a final decision will be made by the DEQ on the permit application.

A DEQ fact sheet is available on the issue, the public comment announcement and other information is also available at: www.deq.state.mi.us/aps/cwerp.shtml.

John Pepin can be reached at 906-228-2500, ext. 206.