Nancy C. Loeb, the director of the Environmental Advocacy Center, is an assistant clinical professor at Northwestern University’s Pritzker School of Law.
Chicago — WHILE the shale gas industry has been depressed in recent years by low oil and gas prices, analysts are predicting that it will soon rebound. Many of the environmental hazards of the gas extraction process, called hydraulic fracturing or fracking, are by now familiar: contaminated drinking water, oil spills and methane gas leaks, exploding rail cars and earthquakes.
A less well-known effect is the destruction of large areas of Midwestern farmland resulting from one of fracking’s key ingredients: sand.
Fracking involves pumping vast quantities of water and chemicals into rock formations under high pressure, but the mix injected into wells also includes huge amounts of “frac sand.” The sand is used to keep the fissures in the rock open — acting as what drilling engineers call a “proppant” — so that the locked-in oil and gas can escape.
Illinois, Wisconsin and Minnesota are home to some of the richest agricultural land anywhere in the world. But this fertile, naturally irrigated farmland sits atop another resource that has become more highly prized: a deposit of fine silica sand known as St. Peter sandstone.
This particular sand is valued by the fracking industry for its high silica content, round grains, uniform grain size and strength. These qualities enable the St. Peter sand to withstand the intensity of fracking, and improve the efficiency of drilling operations.
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