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This sand is your sand, this sand is my sand

Understanding frac sanding mining and the cost of energy in Wisconsin
The sand that you would find on a lake bottom or riverbed (left) differs from frac sand (right) on both an atomic and geologic scale.
The sand that you would find on a lake bottom or riverbed (left) differs from frac sand (right) on both an atomic and geologic scale.

If you drive a car or heat a residence or operate a factory in Wisconsin today, the fuel used to power your engine, furnace, or conveyor belts likely came from beyond state—or even national—borders.

This is because America’s Dairyland doesn’t have oil, coal, or natural gas in deposits large enough to mine. About 8.4% of Wisconsin’s energy comes from renewable in-state sources like wind, hydroelectric, and biomass, according to the U.S. Energy Information Administration. The remaining portion is derived largely from coal, petroleum, natural gas, and from nuclear fission.

The majority of energy surging through the Wisconsin power lines—63% as of 2011—comes from burning coal. The state also imports electricity generated in other states and Canada, transmitted via high voltage networks that crisscross the state.

In 2010 Wisconsin’s per capita energy use, which continues to rise at 3.6% per year, was about 316 million British thermal units (Btus), placing us 26th in the national rankings of percapita energy consumption. Wyoming (948 million Btus) and Alaska (899 million Btus) lead in American per capita energy consumption, while New York (192 million Btus) and Rhode Island (187 million Btus) use the least amount of energy.

We have plenty of power plants here in Wisconsin. What we don’t have are the large-scale fuel extraction operations like the ones found in Wyoming, Pennsylvania, or Alaska. Wisconsin is largely insulated from the diffculties invoived in balancing America’s ever-increasing energy needs with landscape disruption, worker health risks, and environmental pollution. Until recently, the direct cost of energy in Wisconsin was a mostly fiscal one: the price of a gallon of gas or the number on an electric bill.

But this is changing.


The way Americans acquire fuel for their homes, businesses, and lifestyles necessarily evolves with the depletion of finite energy sources. Vertical drilling to access pockets of oil and natural gas carried the domestic energy extraction efforts through most of the twentieth century. As concentrated sources of oil and natural gas dwindle, energy suppliers like Exxon Mobile, Chesapeake Energy, BP, and many others are now targeting more dispersed deposits that require different extraction techniques.

One drilling technique, hydraulic fracturing, has moved to the foreground of efforts to collect natural gas, and sometimes oil, trapped in porous shale rock. Hydraulic fracturing breaks up shale deep underground in order to release these trapped deposits. Like the oil boom of years past, there is a gas rush in America right now, with companies competing to lay claim to large swathes of land containing porous shale rock.

This gas rush is most pronounced in the Marcellus Shale deposit, which stretches from Ohio to New York and underlies roughly two-thirds of Pennsylvania. It’s believed to hold one of the biggest natural gas resources in the country: 43 trillion to 144 trillion cubic feet according to the Unites States Geological Survey (for context, U.S. consumers go through 22 trillion cubic feet every year).

With the American gas rush comes an increased demand for hydraulic fracturing materials, including materials that happen to be found right here in Wisconsin.

The hydraulic fracturing process is as follows: First, extractors drill vertically through bedrock until they reach the shale layer. Then they start drilling horizontally into the shale deposit. To release the shale’s gas, miners shoot a mixture of water and chemicals through the horizontal well-hole and shatter the gas-trapping rock structures. If they simply shattered the rock, it would collapse on itself and the gas would have difficulty flowing into the well. So in addition to water and chemicals, miners also shoot fine-grained sand—Wisconsin sand—into newly fractured shale to keep the cracks propped open, which allows the gas to flow out and into the well.

Not just any sand will work. The sand used for hydraulic fracturing needs particular characteristics of shape, size, and strength that can be imparted only through unique geologic processes. Those geologic processes formed a large deposit of this kind of sand in western Wisconsin.

Hydraulic fracking graphic


“Sifting and winnowing in Wisconsin began a billion years ago,” says Wisconsin’s State Geologist James Robertson. A billion years is the amount of time it takes this type of sand, sometimes referred to as frac sand, to form. Frac sand is defined by its purity, shape, and toughness. It is more than 99% quartz, the grains are highly spherical, and it is extremely hard to crush.

Where sand is almost 100% quartz, the industry calls it silica sand. The name cuts to the atomic heart of the mineral. Quartz is one of many minerals built out of silicon and oxygen, called silicates. In order to understand the extreme strength of quartz sand grains, a little explanation of the atomic infrastructure is in order.

Quartz is comprised of silicon and oxygen. A silicon atom in quartz has four positive charges, and to each of those is bonded a negatively charged oxygen atom. It balances nicely, four negatives bonded to four positives. Many minerals contain silicon bonded to oxygen, but the special attribute of quartz is that its silicon atoms share oxygen amongst themselves: Each oxygen atom in quartz is completing the charge balance for not one but two silicon atoms. That means the atomic scaffolding in that tiny grain of rock is so inter-bonded that a billion years of weathering can’t break it down. In olivine and some other minerals built around silicon-oxygen structures, each silicon atom takes four oxygens for itself and doesn’t share oxygen bonds with other silicon atoms. These minerals are easily weathered.

The quartz-rich crystalline rock of the Precambrian era is very old. According to Robertson, these sands spent nearly a billion years near Earth’s surface, relatively free of overlying rock, where they underwent a cycle of repeated weathering, re-working, and rounding before being swept into the Cambrian sea that eventually deposited them in today’s Wisconsin.

“That was plenty of time for the weak and the halt and the lame of the mineral kingdom to be sifted and winnowed away,” says Robertson. After a billion years, all that was left was the most resistant of all minerals: quartz. And even the quartz started weathering after a while with the hard edges of the sand grains getting chipped away, leaving more spherical bits of quartz.

These well-sorted, atomically fortified grains fit the frac sand bill. This sand, Robertson says, has a crush resistance of 4,000- 6,000 pounds per square inch (psi). That means each grain has the ability to maintain its shape while thousands of pounds bears down on it. Together, the grains can and do bear even more pressure from overlying rock thousands of feet deep.

“You can’t have a bunch of wussy sand that falls apart when you squeeze it,” Robertson says.

The sand mined in Wisconsin and sold to companies for hydraulic fracturing is anything but wussy. It’s the best sand in the country for the job. Other places in the United State have had the requisite geologic sequence that allows quartz to concentrate into a material that could be used for hydraulic fracturing.

But, Robertson says, Wisconsin’s silica sand has three characteristics that make it the most desirable: it’s near the surface, it’s loosely packed, and it’s often found next to existing railway lines making bulk transportation easier.

And so, as energy extraction evolved to include hydraulic fracturing as a mainstream technique, Wisconsin stepped into the energy industry in a big way. The dairy state now indirectly helps feed the country’s appetite for power as well as cheese. No longer simply an importer of energy, Wisconsin is playing a role on the front end of the supply chain—the end where people also make money on energy instead of simply paying for it. Wisconsin, it seems, now must face the same challenges as other states that host energy production.


This new role for Wisconsin, as contributor to energy production, began in earnest just a few years ago. In July 2011, there were sixteen frac sand mines in the state, according to the Wisconsin Center for Investigative Journalism. Over a year later, in October 2012, the Center reported that number had jumped to 37 active frac sand mines with an additional 41 permits granted but not yet active.

State Geologist Robertson says that while the state has a history of sand mining, the scale of these mines is something new: the combined area permitted for frac sand mining has been estimated to be 40,000 acres, an area larger than the city of Green Bay, or, put another way, roughly 30,250 Lambeau Fields.

Counties where the frac sand industry has set down roots include: Barron, Buffalo, Chippewa, Clark, Columbia, Crawford, Dunn, Eau Claire, Green Lake, Jackson, La Crosse, Monroe, Pepin, Pierce, St. Croix, Trempealeau, Waupaca, and Wood. The sandstone formations of Cambrian age being mined are the Jordan, Wonewoc, and Mt. Simon, and the St. Peter is of the slightly younger Ordovician era.

 The condition of a frac sand deposit and its location in the landscape determines the type of mine that is constructed and its support facilities. Some of the beds have weathered significantly and their loosened sand has eroded and collected nearby where it can be excavated with relatively little effort.

“One of the requisites of frac sand is not only that the rock be made up of quartz grains that are rounded and tough and of a certain size, but that you can get the darn things apart,” Robertson says. “Because you want the individual grains, you don’t want them all clumped together in a solid rock.”

Yet in some places the sand deposits are still cemented and removal requires blasting to break up the bedrock and then crushing to reduce the big chunks and free the sand. Like the loose sand, rock beds can be on low ground and require a pit for extraction.

In other areas, the sandstones will occur on the lower slopes of bluffs and extraction is via tunneling; or if deposits are near ridge tops, extraction requires removal of all the overburden (overlying rock beds and debris). Geologists have noted that one desirable frac sand formation lies just below the widely quarried Prairie du Chien dolomite, a kind of limestone, and that some old dolomite quarries may find new life with an excavation of the quarry floor.

Regardless of the mining process, all the operations require washing of the sand to remove clay and other impurities. After drying, some sands are sorted by size to produce a more uniform and desirable product.

If all active and inactive permits were fully developed, the Wisconsin Center for Investigative Journalism estimates approximately 3,000 jobs could be generated by the mining activity. In a time of high unemployment, such job growth, especially in struggling rural counties, is significant.

The rapid growth of the frac sand industry is causing people in western Wisconsin and across the state to voice their hesitancy about how the mining is conducted, and how their communities and landscapes will change because of it. As a valuable resource for the energy industry, Wisconsin’s sand is an economic boon. But it also carries challenges associated with any large-scale landscape change and the concerns of any expansive extractive process.

Frac sand discussions in the state thus far seem to fall into one of two camps: pro-jobs or pro-environment. But the communities overlying these valuable silica sand deposits know that the choices involved in frac sand mining aren’t so simple. Sand mining is not new to Wisconsin, it has a history stretching back more than one hundred years. What is new, and what is prompting concern, is the scale of the mining. In community forums, newspaper editorials, and other venues, Wisconsinites, while optimistic about the prospect of jobs and industry returning, have also wondered about the impact frac sand mining will have on local water, air, and soil as well as the mines’ effect on a community, ranging from its roads to its social fabric.


Some frac sand mining impacts, such as whether or not mines intersect endangered or threatened species habitats, can be assessed by comparing geographic boundaries. The Wisconsin Center for Investigative Journalism found that several mines overlapped the Karner Blue Butterfly habitat, an endangered butterfly whose protection is widely publicized by the Wisconsin DNR but of which the mining companies were not initially aware. Excavating Karner Blue Butterfly habitat is only one of a thousand decisions that are and will be made in regard to frac sand mining. As citizens of Wisconsin, it is up to us to educate ourselves and be a part of this decision-making process.

One way to get involved is to look to the scientists and researchers who understand the natural systems operating both above and below the land surface. Hydrogeologist Michael Parsen at Wisconsin Geological and Natural History Survey says that mining’s effects on the local water table should be monitored. As with any extraction effort that involves cutting down into the earth or removing rock through blasting, proximity to the water table should be considered. Also, the relatively large amounts of water each facility draws from local sources for processing may affect local water supplies—though many mines do recycle a large percentage of the water for re-use within their operation.

Frac sand production uses chemicals called flocculants to remove unwanted minerals and clay particles from the frac sand. According to Wisconsin Department of Natural Resources (DNR), at low concentrations the kind of chemicals typically used as flocculants biodegrade. But at the larger scale of frac sand operations, a question lingers as to how higher concentrations of flocculants entering the local environment will be tracked and monitored.

Air quality, much like water quality, should be central to any discussion. Besides emissions like truck exhaust that are common to many industrial activities, frac sand mining produces dust, or particulate matter, that could affect local air quality. Wisconsin does regulate industrial emissions, and, according to the Wisconsin DNR, sand mines are required to avoid having “... adverse impact on visibility through atmospheric discoloration or reduction of visual range due to increased haze.”

Since silica dust is a known health hazard in sand processing facilities, both the U.S. Mine Safety and Health Administration and Wisconsin DNR require mining operations to control worker exposure. However, some communities have expressed concern as to whether the silica dust from large-scale operations can also become a hazard for nearby residents. Research has yet to yield an answer to this question. As the scale of mines increases, so does dust creation. Some sand mines are engaging in voluntary monitoring and minimizing the amount of silica dust leaving their facility. It is not required by law, though, and the Wisconsin DNR has yet to establish regulations regarding an acceptable threshold of silica dust particles entering communities adjacent to frac sand operations.

Additionally, Parsen suggests that any plans for new or existing sand mines should consider what the mine will become after it is no longer in production and how much water will be required for future land use. Wisconsin law requires that each mine submit a reclamation plan before they begin excavation. Community members can find out about and sometimes help shape the mining company’s plan for the land after mining ends.


As an activity that changes the land, large-scale mining has social as well as ecological considerations for Wisconsinites to ponder. While water and air quality can be measured, the impact to a community’s perception of its landscape is a bit more subjective. UW–Stout Professor of Social Science Thomas Pearson notes that in addition to dividing a community along an opinion rift—those for versus those against—a frac sand mine can disrupt the visual connections to a once familiar place. In many cases nostalgia and sense of place fuel objections to a proposed mine well before environmental or health considerations are even discussed. For this reason, Pearson says, reaction to Wisconsin’s new frac sand mines has been strongly negative in some communities as residents grapple with the question, How do we as a community define who has a right to permanently transform the way a place looks?

Difficult and uncomfortable to answer, this is one of many questions to be faced over the next few years as our communities, state, and country struggle to accommodate energy needs. With the increased use of hydraulic fracturing for natural gas and oil extraction and the subsequent sand mining boom affecting communities across Wisconsin, the biggest question for us may be: What are we willing to exchange for our energy consumption?

One thing is for sure, say’s State Geologist Robertson, “For better or worse, Wisconsin is now a player in the energy game.” Even though the scale of mining activity has caught people off-guard, the jobs that come with energy production are a boon to many residents of western Wisconsin. But there are lots of question trailing after those jobs—more questions than there are answers in some cases. Communities, organizations like the Wisconsin DNR and the Wisconsin Geological and Natural History Survey, and the frac sand mining companies themselves are working to offer answers.

The Wisconsin Academy of Letters, Arts & Sciences will over the course of this year provide as much context and clarity as possible for this issue, and bring in as many diverse community perspectives as possible to enhance understanding of our climate and energy future. 

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Emily Eggleston Toner is a Purdue Extension Educator in Urban Agriculture. She received her journalism graduate student at UW–Madison, specializing in science, environment, and food topics along with multimedia production. An Iowan by birth, Eggleston has a bachelor's degree in agronomy from Iowa State University.

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