Descending a few dozen feet into the open pit mine, visitors enter a monochromatic world that looks like a desert planet from Star Wars. On all sides, walls of nearly pure quartz sandstone rise up, the sparkly tan of raw cane sugar, layered with bands of different shades. Loose sand sits in small piles at the base of the cliffs; in the distance, larger piles are being loaded into huge yellow dump trucks that can move 70 tons of the stuff at a time.
But they’re not digging for valuable ores or precious metals buried beneath all this sand. This is a sand mine, and there are dozens like it in western Wisconsin. This state, and others in the Midwest, have some of the best sand in the world.
Sand has been mined here for over a century. It’s used for glass, casting in foundries, even playgrounds and golf course sand traps. But in the last 10 to 15 years, the industry has exploded because this sand has specific characteristics. It’s pure — almost entirely quartz, or silicon dioxide — and the particles are round. This combination makes Wisconsin sand ideal for use in another extractive industry: hydraulic fracturing, or fracking, in the quest for natural gas and oil.