The latest buzz term in the US aggregates industry is ?frac sand?. This sand product ? high in silica content ? is used in the hydraulic fracking process to extract natural gas from deep deposits. A mixture of sand, water and chemicals blasts open the rock, then the sand holds open the fractures to release gas to the surface.
Currently, about a quarter of all energy used in the US is natural gas, and that percentage is expected to grow. High energy prices have made the process of extracting natural gas a profitable business, resulting in escalating frac sand prices. And some aggregate producers are cashing in.
If frac sand is the new ?gold?, then the new ?gold rush? is in the Mississippi River Valley areas of Illinois, Wisconsin and Minnesota.
Tony Runkel, Minnesota?s chief geologist, said those areas have the potential to turn into a hot spot for frac sand mining. ?There?s a huge amount. This sandstone layer that they?re targeting is very, very extensive,? Runkel says. ?What?s relatively rare is where it occurs ? in a setting where it?s close enough to the land surface that it can be mined in an economically feasible fashion.?
LOADED WITH CONTROVERSY
Although the material is plentiful and the price high, there?s a catch. Hydraulic fracturing is loaded with controversy, as the process and the chemicals used are reported to be responsible for contaminating ground water and creating environmental problems.
Such fears have resulted in a hold on gas exploration in certain areas until further study is done, and New York State lawmakers are also reportedly contemplating a moratorium.
Scientific American has reported that a new study sampled water from 60 wells and found evidence for natural gas contamination in those within a kilometre of a new natural gas well. The magazine quotes environmental scientist Robert Jackson of Duke University, who led the study: ?Methane concentrations in drinking water were much higher if the homeowner was near an active gas well.?
Methane in well water is not unusual; however, by measuring the ratio of radioactive carbon present in the methane contamination, the researchers determined that in drinking water wells near active natural gas wells, the methane was old and therefore fossil natural gas from the Marcellus Shale, rather than more freshly produced methane.
?This marks the first time that drinking water contamination has been definitively linked to fracking,? said Scientific American. ?In fact, concentrations were 17 times higher in those drinking water wells within one kilometre of an active natural gas well than those farther away.
?The US Department of Energy has convened a special task force to improve the safety and environmental impacts of such fracking for natural gas, including how best to dispose of the voluminous wastewater as well as ensuring proper sealing of wells to prevent such groundwater contamination.?
In the meantime, aggregate producers are cashing in on the demand for frac sand, and it is the hot topic at industry gatherings.
MINING FRAC SAND
According to the Milwaukee-Wisconsin Journal Sentinel, it?s easy to mine frac sand in Wisconsin, because it?s easy to burrow into the bluffs. The report says there are no mine shafts to dig and no water to pump because it is above the water table.
Associated Press reported that an energy company bought 62 hectares (155 acres) of land near Red Wing, Minnesota, for $US2.6 million earlier this year. It intends to use the land as a sand pit, though reportedly no permit application had been made at the time of the report. Despite this, local residents were already meeting to discuss the environmental and health questions.
In addition to local opposition to frac sand mining, opposition to the hydraulic fracking process is occurring at the national level.
The Citizens for Water Foundation (CWF) is ?committed to protecting and preserving America?s water resources today and for all future generations?. According to CWF representatives, the group is concerned about the accelerating development of extreme methods of fossil fuel extraction throughout the United States and, specifically, hydraulic fracturing in the north east.
?Fracking and other extreme fossil fuel development present dangerous and shortsighted solutions to the world?s energy needs,? said CWF co-executive director Joe Levine.
With increasing opposition to hydraulic fracturing and new frac sand mines, it is difficult to determine how long the process will remain a viable alternative to other energy sources. And with an Environmental Protection Agency study now in the works, new regulations could change the landscape.
In the meantime, aggregate producers ? particularly in the Mississippi River Valley ? are continuing to turn a good profit with the new ?white gold? that is frac sand.
Darren Constantino is the editor-in-chief of Pit & Quarry (US). This article was originally published in the August 2011 issue of Pit & Quarry and is kindly reprinted with permission.
What is frac sand?
Frac sand is generally large-grain sand high in silica content. The material is usually 20/40 mesh, 40/70 mesh or 100 mesh. The smallest of these ? 100 mesh ? is the most common type used for hydraulic fracturing of Marcellus Shale, which extends throughout much of the Appalachian Basin. US Silica ships the product from Illinois to Pennsylvania for distribution.
According to the Barron News Shield of Barron, Wisconsin, the price of frac sand has a tendency to fluctuate with the price of oil. The paper quotes mine-permitting attorney Gerry Duffy: ?What makes it valuable is they have to dry it. They have to get it down to one per cent moisture content, which means once they dry it, they?ve got to store it inside, or ship it in hopper railcars because they can?t expose it to the atmosphere, because they?ve dried it down.?
Duffy reports that in the past three years, he has seen frac sand being sold from $36 to $96 per tonne. Duffy adds that there is a lot of demand for US-mined frac sand in Canada.