Frac sand is a type of sand with small, uniform particles. It is injected into the rock formation along with the water used to fracture the rock in the process known as hydraulic fracturing ("fracking"). The sand is used to prop open the fractures that are created. Because the particles are uniform, fluids like water, oil, and gas are able to flow through the spaces between the particles. Frac sand is currently mined in a range of states, with the Great Lakes Region, consisting of Illinois, Minnesota, Michigan, and Wisconsin, contributing approximately 70% of the silica sand used in America as a proppant in 2014.
- Mining: Frac Sand (Webpage), Wisconsin Geological Survey
A short overview of frac sand, where it is found, and how it is mined, with links to other resources.
- Frac Sand in the United States (Report), U.S. Geological Survey
A geological and industry overview of frac sand mining in the U.S.
- DNR and Silica Sand (Webpage and Map), Minnesota Department of Natural Resources
Webpage on frac sand mining in Minnesota, with information on relevant legislation, answers to frequently asked questions about frac sand, and a map of sand mines in Minnesota.