What is frac sand? American Geosciences Institute

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.

Wisconsin frac sand sites double - Wisconsin Watch

Mining for sand for fracking holds risks for communities, study says - Los Angeles Times

Brown Fracking Sand U.S. Geological Survey

Frac Sand Mines & Related Facilities

North America Proppants Market Size & Share Analysis - Industry Research Report - Growth Trends

So why is Wisconsin the center of the frac sand boom?, Writers

Opinion The Sand Mines That Ruin Farmland - The New York Times

As supply meets demand, Wisconsin's frac sand rush slows - Wisconsin Watch

Frack Sand in Utah? - Utah Geological Survey

Hydraulic Fracturing Sand Resources

The fight over frac sand mining in Wisconsin - Isthmus