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Silica sand mining

Silica sand mining operation
Photo: Mary Kenosian


In 2010 the MPCA began receiving public inquiries about projects to mine silica sand for use in hydraulic fracturing, or “fracking,” a drilling method used for natural gas and oil wells. Southeastern and south central Minnesota and southwestern Wisconsin have extensive deposits of sand that meets the specifications required for fracking. Mining of certain types of these deposits has been occurring in the region for many years; however, there are new issues based on the quantity, type and depth of mining.

Residents near silica sand projects have recently contacted state and local governmental agencies with concerns about potential health risks associated with silica, for example, silicosis. The MPCA is sensitive to residents’ desires to know more about health or environmental risks of projects proposed for their communities.

Where are the silica sand activities located in Minnesota?

Minnesota state agencies collect data on the locations of silica sand-related activities and sites. Agencies collect different data because regulatory authority of each type of activity varies between regulatory agencies. The three general activities related to silica sand are: transport load, processing facilities and mines.

Who has jurisdiction?

Local governments generally have the greatest opportunity for approving and supervising sand and gravel mining operations. Local units may have specific regulations for development, operation or reclamation of a pit. The MPCA and DNR do not have regulatory authority over the end use of mined silica sand.

MPCA and DNR permits may also be needed (e.g., water quality, discharge and appropriation; wetlands and air emissions). The Environmental Assessment Worksheet (EAW) threshold is operations that will exceed 40 acres to a mean depth of 10 feet. The local unit of government is generally the Responsible Governing Unit for environmental review.

Are MPCA permits required?

Generally, yes. The MPCA issues air and water permits for many sand and gravel mining operations. However, these permits typically do not have requirements specific to silica sand mining. Under certain circumstances, the MPCA may issue permits for sand storage sites.

Air permitting

MPCA air permits are issued to sand and gravel mining facilities to control air emissions from combustion sources such as dryers or particulate matter such as blowing sand.

The MPCA will continue to work with stakeholders and adjust permitting requirements as information becomes available.

For more information on air quality permits, check these publications on the MPCA website:

Water permitting

MPCA water permits are issued to facilities that conduct a variety of mining activities such as sand and gravel mining. Typical pollutants regulated in sand and gravel mining discharges are total suspended solids, iron and pH. Based on our current understanding of silica sand mining operations, we do not anticipate specific or unique environmental or health risks that are not already addressed though the current water permitting processes.

Currently permitted sand and gravel mining facilities will likely be able to also mine frac sand without modification of the existing permit. New facilities will be required to apply for permit coverage. For links to more information on MPCA wastewater permitting, visit the Water Permits and Rules page.

Are there health risks?

The potential air pollutants of most concern from silica sand mining are airborne particles, including particles less than 10 microns in size (PM10), particles less than 2.5 microns in size (typically called “fine particles” or PM2.5), and respirable crystalline silica, which ranges across both size categories.

There are two methods of determining whether or not there are potential health concerns from air pollution: monitoring and computer modeling. There are known health risks associated with airborne crystalline silica. However, the available information on health effects comes almost exclusively from occupational settings, where exposures are more concentrated.

There are no federal or state standards for silica in ambient air; however, the MPCA uses an MDH Health Based Value value for respirable crystalline silica of the particle size smaller than 4 microns to assess the potential for human health effects. The MN Department of Health reviewed this health benchmark, and included the value and documentation on their Air Table website.

There also are health risks associated with other airborne particles, especially PM2.5. There are state standards for airborne particles (called Total Suspended Particles or TSP), and state and federal air quality standards for PM10 and for PM2.5. Learn more about fine particles.

The MPCA has received some limited air measurements for particles around silica sand operations, and will continue to receive more. These results are available on the Preliminary air monitoring data at Minnesota silica sand facilities page. If you would like to receive raw data tables for this ambient air monitoring data set please contact Jeff Hedman (at 651-757-2416 or or Kristie Ellickson (at 651-757-2336 or

What is the MPCA doing to address concerns?

We continue to work with the state of Wisconsin and our own Departments of Natural Resources and Health to find out what information is available and assess whether current science indicates any regulatory changes should be made. The Wisconsin Department of Natural Resources has extensively examined these issues, and recently concluded, “Very little conclusive information exists regarding sources, controls or levels of silica in ambient air; this means it is not possible at this time to determine conclusively whether or to what extent the quantity, duration or types of silica emissions in Wisconsin may be a public health concern.”

In 2012, Wisconsin DNR released a study summarizing current information on silica sand mining, its possible environmental impacts, and local, state and federal regulations that address sand mining and processing: PDF Document Silica Sand Mining in Wisconsin External Link

The MPCA will continue to investigate specific complaints related to silica sand mining and storage sites and take action, when appropriate, to minimize health risks and environmental impacts. The MPCA also can provide technical assistance to local units of government regarding air monitoring at or near silica sand mining operations in Minnesota.

Dust, traffic, etc. may be concerns for nearby residents. Local governments usually are the first point of contact for these issues. MPCA issued this guidance: PDF Document Facts About Odors, Noise and Dust for Local Government (2-05) .

A number of sand mining proposals are going through environmental review at the local level in Minnesota. The environmental review process provides opportunities for community engagement on issues of concern.

For more information

  • To file a specific complaint with the MPCA, visit the Citizen Complaint page.
  • For more information on silica sand mining and handling, contact Ralph Pribble in the MPCA Public Information Office, Call the MPCA at 651-296-6300 or toll-free at 1-800-657-3864.
  • For more information on sand and gravel mining in Minnesota, contact the HTML Content Minnesota Department of Natural Resources External Link.
  • For answers to health questions about silica sand exposure, contact Jim Jacobus at the Minnesota Department of Health, 651-201-4917 or
  • Contact local county offices to find out more about local silica sand mining or handling projects. Goodhue County has information on silica sand projects in the county on its website.
Last modified on December 26, 2014 14:40

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