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What is silica and why is mining it controversial?

RED WING — Demand for silica sand has driven what some are calling "the new gold rush."

Since 2008, Wisconsin has built 16 silica sand mines. Eleven more have recently been approved and at least 14 others have been proposed. Energy companies appear to have targeted Minnesota next.

In 1998, the Minnesota Department of Natural Resources listed just three silica mines in operation around the state; an updated statewide figure was not available, as permits are issued by counties. The eight counties in southeast Minnesota now have just one small silica mine in operation. It opened in 2008 near Lanesboro in Fillmore County. However, at least five mining permits have been requested in recent months, including three in Winona County and one in Olmsted County.

Demand for silica sand has exploded in recent years as energy companies have embraced the controversial practice known as hydraulic fracturing to extract oil and natural gas through horizontal drilling. According to Curt Parsons, CEO of the Texas-based energy company EOG Resources, the United States experienced an increase in domestic oil production in 2010 for the first time since 1985 based largely on silica sand being more widely available.

The unusually strong, perfectly round sand particulates commonly found throughout the Midwest, primarily in the Jordan Formation, are combined with water and chemicals before being injected into horizontal crevasses deep underground to allow for easier extraction of oil and natural gas.


"One of the reasons this area is so popular or lucrative is because the sand is like miniature ball bearings," said John Litsenberg, a member of Goodhue County's silica sand study group who worked at two silica mining sites before retiring this summer.

Health concerns

While some are concerned about the "fracking" process itself — for example, South Africa has imposed a moratorium on it to study the environmental impact — the top concern for many are health problems from silica sand mining.

The National Toxicology Program in the United States and the International Agency for Research on Cancer, a branch of the World Health Organization, both classify crystalline silica as a known carcinogen. Amorphous forms of silica, meanwhile, are a "possible carcinogen." Concerns arise when the sharp, microscopic particles are breathed in and become lodged in the lungs, eventually building up to dangerous levels.

The difference between the two forms of silica is often razor thin. A 2011 report from the Wisconsin Department of Natural Resources says distinguishing between crystalline and amorphous silica is "not always clear cut" and that the forms of silica can change depending on temperature and treatment.

Though the Occupational Safety and Health Administration regulates the construction of mines and the Mine Safety and Health Administration regulates active mines, silica particulates remain a wild card. The Wisconsin DNR reports there are no federal air quality standards for silica and just seven states have adopted their own standards; Wisconsin and Minnesota are not among them.

In addition, there are no generally accepted methods for monitoring the 4-micron particles that cause the most health concerns, such as silicosis, cancer, kidney damage, enlargement of the heart and other pulmonary diseases, according to the same Wisconsin DNR report.

That was the primary reason University of Wisconsin-Eau Claire professor Crispin Pierce decided to begin studying the air around a sand mine in 2008. The UWEC Director of Environmental Public Health Program has been monitoring silica levels in the air around an EOG Resources site in Chippewa Falls, Wis., for three years, and hopes to make his results available to the public by the end of the month.


Pierce says it can take 10 to 15 years for many long-term health concerns to manifest themselves, but he advocates for more strict oversight and regulation to be imposed immediately.

"It's a little bit of a new animal in the sense we have a lot of these new sites near population centers," Pierce said. "What we do know is silica causes silicosis and cancer. The question is where do we put the monitors? We have to be fair to these sand companies … (but) it's an extra step that sand companies need to take."

Shifts in thinking

Local critics think there might be a more fundamental step that needs to be taken.

"There's another (question) that no one wants to talk about," said Red Wing resident John Tittle, who's a member of Save the Bluffs. "Do we want to be a mining economy? We could really turn into something like the Iron Range."

The current price of high-quality silica sand ranges from about $50 to more than $100 per ton. Goodhue County contains hundreds of millions of tons, meaning it could turn into a multi-billion dollar industry that employs hundreds during the next few decades. That fact is tied in to the other concerns.

Industrial sized silica sand mines typically require millions of gallons of water each day to operate, and often tap into the local aquifer for that supply. One mine in Chippewa Falls has asked to use 200 million gallons a day, for example. That remains an ongoing concern in Chippewa Falls, where 10 mines could be in operation by 2013.

Geological studies classify Goodhue County's water supply as very susceptible to pollution from mining operations.


"They are doing everything a company can do to address the water issues, but until you study, model and measure it, you can't really know what the impacts will be," Wisconsin conservation officer Dan Masterpole said of the Chippewa Falls situation.

Trucking is another concern related to the scope of the mining project. Some county officials have expressed concerns over the wear-and-tear on local roads, which could see far more use than previously expected, and who would pay for the necessary repairs.

Property values drop

Economic and social concerns revolve around what numerous new mining sites could do to tourism and property values. Goodhue County benefits from a $65 million tourism industry, which some think would be negatively affected by extensive mining in and around the Mississippi River and bluffs. In addition, Auburn University economist Diane Hite says property values around quarries drop by an average of 20 percent for residents within a half mile, and 4.9 percent for those within three miles.

The type of mine also plays a role in the controversy. Open-pit mining allows for more efficient recovery of deposits and are better for the company's bottom line, while underground mines require more manpower and must leave behind a portion of the material — called "overburden" —to operate safely.

Any deposit closer than 100 feet to the surface would likely function as an open-pit mine, according to Litsenberg, including most silica sand mines in southeastern Minnesota.

"I'll admit, surface mines are not a pretty sight," Listenberg said. "I have less difficulties with underground mines."

Information hard to come by


Getting information from most energy companies involved with silica mining is difficult, due to the increasing controversy.

Windsor Permian of Oklahoma purchased 195 acres in Goodhue County for about $3 million in February. The company said in a letter that it plans to turn that land into the county's first silica mine. However, no company officials have identified themselves at any public meetings, it has yet to file a permit request and no one has indicated which sort of mine — surface or underground — it would create.

In addition, calls to EOG Resources seeking a tour of its Chippewa Falls facility were rejected — even though a public tour was planned for the very next day; citizens and media were not allowed to ask questions of mining representatives during the seven-hour tour for county officials. Unimin, which operates a silica mine near Le Sueur, Minn., also rejected the Post-Bulletin's request for a tour.

"We've worked really hard to be a good neighbor," Unimin site president Grey Lusty said. "I wouldn't say we've always been noncontroversial, but I think we learned our lesson a long time ago. Being a mystery just is not helpful. The more we can be transparent, the better this process has gone.

"(But) in the last 12 months, things have gotten really crazy. It's really heated up. Everyone is sort of like a cat on a hot tin roof right now."

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