CHIPPEWA FALLS, Wis. - The rolling hills and scenic bluffs of western Wisconsin and southeastern Minnesota hide a valuable resource that has sparked what's been called a modern-day gold rush.
The object of desire is not gold but a soft sandstone needed by drilling companies to unlock underground natural gas and oil supplies in a controversial practice called hydraulic fracturing, or fracking.
Largely overlooked in the national debate over fracking is the emerging fight in the U.S. heartland over mining "frack sand," which has grains of ideal size, shape, strength and purity. Mining companies say the work provides good jobs in rural areas, but some residents fear the increase in mining could harm human health and the environment.
"More and more people are waking up to the fact that there are difficulties with this massive explosion," said Pat Popple, a retired school teacher and principal and anti-sand mining activist.
U.S. frack sand producers sold or used more than 6.5 million metric tons of sand worth $319 million in 2009, according to the U.S. Geological Survey. The tonnage likely will have doubled when 2010 data is released, said Thomas Dolley, a USGS mineral commodity specialist who follows the silica mining industry.
"It's huge," Dolley said. "I've never seen anything like it, the growth. It makes my head spin."
Nearly three-fourths of frack sand comes from the Midwest. It's shipped by rail hundreds of miles to the oil and gas fields of Texas, Pennsylvania and North Dakota, where drillers mix it with water and chemicals, then force it deep underground to fracture shale deposits that hold gas and oil that couldn't be tapped conventionally. Critics say the process can diminish water quality and even cause earthquakes.
John Felmy, chief economist with the American Petroleum Institute, said opponents of hydraulic fracturing are "fundamentally misguided" and the environmental fears are unwarranted. The surge in sand mining has extended the domestic energy boom to portions of the country that don't produce much fuel, bringing jobs and economic development, he said.
Frack sand mining has had a foothold in Wisconsin's Chippewa County since 2008. The most visible sign is the huge new EOG Resources Inc. plant in Chippewa Falls, where a steady parade of shiny new trucks delivers a load of orange sand from a nearby mine every few minutes.
The plant, which still is in the start-up phase, will bring 40 to 50 full-time jobs to the community, while mining contractors now employ about 25 people and the trucking company that delivers the sand has added more than 70 jobs, company spokeswoman K. Leonard said.
But not everyone is excited about the growth. On a recent windy day, Heather Andersen, of Bloomer, another retired schoolteacher turned activist, watched as gusts of 30 to 40 mph blew dust off sand piled up at the Superior Silica Sands LLC mine northwest of Chippewa Falls. She said she saw no signs the mine kept the sand watered down to suppress the dust.
"That stuff you see is not dangerous," Andersen said. "It's the stuff you can't see."