Silica Sand Mining is Back - Scott County

Silica Sand Mining is Back
Thirty years ago, the J.L. Shiely Company opened a silica sand mining operation halfway
between Shakopee and Jordan on the river side of Highway 169. They mined silica sand to be
used for a relatively new process at that time called “fracking” to enhance oil production from oil
wells. They also sold some silica sand for other commercial uses. Silica is the primary
ingredient in glass manufacturing and is used in water filtration and treatment, sand blasting, and
a number of other commercial uses. The Shiely mining operation closed after about 10 years,
due to market changes in the oil industry. When Middle Eastern oil became available much
cheaper than it could be produced in this country, the demand for “frac sand” plummeted.
Market changes in oil prices are again the cause for the current increased demand for silica sand.
Currently, the demand is so great that some are calling the flurry of new silica sand mining
efforts “the new gold rush.” There are legitimate debates going on about whether or not the shift
from Middle Eastern oil toward domestic sources (such as tar sands, shale imbedded oil, and
natural gas) is better than rapidly developing alternatives to fossil fuel energy. However, that is
not the focus of my article, though I would encourage everyone to learn more about this issue.
I want to inform readers on how Scott County is responding to the demand for silica sand
mining. Other counties that have silica sand resources are struggling with the environmental and
land use implications, and some are calling for moratoria. LeSueur and Scott Counties, however,
have had previous experience with silica sand mining and perhaps have a better understanding of
the issues surrounding such mining. As a result, the mining proposals here and in LeSueur
County have been less controversial.
Silica sand is a naturally occurring non-metallic mineral. Sandstone, which is silica sand
particles cemented together, was deposited nearly 500 million years ago. According to the
Minnesota Geological Survey as noted in the Scott County Geologic Atlas (copies are available
for free from our office), a shallow sea covered much of North America, including parts of
Minnesota. Over a 200 million year period, sediments were deposited in that sea. These
deposits eventually became the bedrock that is exposed in places along the Minnesota River in
the Twin Cities metropolitan area, and throughout south eastern Minnesota. About 600 feet of
sandstone, shale, and dolomite were deposited during that time. In three separate invasions, seas
covered the area, spreading beach and near-shore sands, which were to become the Mt. Simon,
Galesville, Ironton, and Jordan Sandstones. The final location of these deposits as we see them
today were further impacted by shifts in the earth’s crust, wind, water, and ice erosion over
millions of years.
Where limestone and sandstone deposits are closer to the surface they can be easily mined, and
limestone mining has been active along the Minnesota River Valley for over 100 years.
Limestone was a basic building material long before the invention of concrete. Sandstone was
also used when it was naturally strongly cemented together, but the Jordan sandstone is relatively
loosely cemented (allowing for crushing to separate the individual grains of silica sand). This
sand has a relatively consistent particle size. The strength of the pure silica granules, which are

approximately the size of sugar granules contribute to its value in an oil well enhancement
process called hydraulic fracturing or “fracking.” You can research this on your own.
What are the environmental implications associated with mining silica sand Largely, the
answer to this question is that they are the same as mining sand, gravel, or limestone with a few
additional concerns related to unique settings. The Jordan sandstone formation throughout
southeastern Minnesota serves as a valuable source of drinking water called the Jordan aquifer.
Sandstone is porous, and the open spaces between the sand grains hold water which can easily be
tapped by a well and pumped out. Water flows through sandstone formations relatively easily,
allowing for infiltration and underground migration toward discharge points. Here in Scott
County, the primary discharge point for the Jordan aquifer is the Minnesota River. Because it
serves as an aquifer, concerns about mining into it always include concerns about impacts to
drinking water resources. The proposed mines are adjacent to the aquifer’s natural point of
discharge, minimizing the potential for adverse impacts.
Mining always involves the transport of products, so traffic concerns must be addressed. In the
case of the two proposed mines, the primary means of transporting their silica sand product (frac)
will be by rail. This will result in several additional trains through Shakopee every day.
Similarly, the mines in LeSueur County will be increasing their output of silica sand being railed
through Shakopee.
Mining generally also involves increased risk for dust problems; with silica, like some other
minerals including asbestos, these dust particles have been shown to be associated with
respiratory problems, especially the smaller particles that are sharp edged and can lodge in the
lungs. The condition called silicosis has been well documented, especially among workers
exposed to this dust in high concentrations for long periods of time. Silica is one of the most
common minerals on earth, so everyone is exposed to silica dust. Exposure to silica dust is
regulated by several agencies in the United States for workers through the Occupational Safety
and Health Agency (OSHA) and the Mine Safety and Health Administration (MSHA). In
addition, in Minnesota, exposure to surrounding populations from sources regulated through air
quality permits (as these mines will be) is regulated in the form of nuisance dust by the
Minnesota Pollution Control Agency. Monitoring and dust controlling mitigation plans will be
required of these mines to minimize dust problems.
Additional concerns from mining in general include noise and blasting impacts to surrounding
property through ground waves or air blast impacts. Considering that blasting of limestone in the
areas being proposed for silica sand mining has been going on for decades without significant
issues demonstrates that both noise and blasting impacts can be controlled adequately.
Scott County just completed an Environmental Assessment Worksheet (EAW) for the Great
Plains Sand mining project at the location of the previous J. L. Shiely mine that closed 20 years
ago. By the time this article is published, it is anticipated that an Interim Use Permit (IUP) will
have been issued as well with conditions established to address all of the concerns identified
through the EAW process and additional issues that came to light during the IUP process. That
permit will be held somewhat open to enable adding additional conditions as deemed necessary
to protect the public. A Great Plains Sand Advisory Committee will also have been created

consisting of representatives from Sand Creek and Louisville Township, the project developer
and Scott County with others such as representatives from the adjacent U.S. Fish and Wildlife
Refuge participating as needed. This advisory committee will review operations and recommend
changes to the IUP conditions and to the mine operator to address concerns which may arise.
The other and much larger mining proposal is the Merriam Junction Sands proposed for the area
previously occupied by Bryan Rock, River Warren Rock, the Renaissance Festival, and other
properties adjacent comprising almost 1,000 acres. That project because of its size is subject to
preparation of a much more intensive analysis called an Environmental Impact Statement (EIS).
That is still being prepared and will provide several opportunities for public review and
comment.
Scott County has always held the rights and safety of the public as the highest priority. The
focus of the County Board is to ensure “safe, healthy. and livable Communities.” The approach
to preparing the environmental review documents for the silica sand mines involved an increased
effort to collaborate with the township officers providing interested citizens additional
opportunities to communicate their concerns through their closest elected officials. The
environmental review process as well as the Interim Use Permit process is open to public
participation. Documents available for public review and comment are posted on the County’s
website: just click on the scrolling notice called “Silica Sand Mining Proposals.” You can
receive automatic emailed notification of new postings about these projects by subscribing
through E-Services. Check this out at www.co.scott.mn.us.