30 May 2012
One of the spinoff industries associated with hydraulic fracturing of shale rock is silica sand mining. During the “fracking” process, sand is mixed with water and chemicals and pumped under high pressure to force open voids in shale. The sand is needed to prop open cracks and release gas, oil and other valuable hydrocarbons collected from the well.
When it comes to “fracking,” evidently, not any old sand will do. Drillers prefer sand that’s well rounded, well sorted, and chemically inert, relatively speaking. Some of the best “frack” sand comes from the Jordan Formation in Minnesota and Wisconsin, which contains pure quartz sandstone sedimentologists describe as super mature.
The sandstone QFL diagram shown is a colorful Wiki-Commons adaptation of works by Robert Folk, and William Dickinson, who related sandstone texture, composition, and fabric to tectonic depositional environments. The Q stands for quartz (but not chert), F for feldspars, and L for lithic fragments. The Jordan sandstone would plot at the apex of the QFL triangle.
As expected, not everyone is enthusiastic about the recent flurry of mining activity. Operations bring more truck traffic, noise, dust, and worry to some residents of this pastoral up-north country. For others in a position to sell land, mineral rights, heavy equipment, tanks, and services, silica sand is the new gold.
The Wisconsin Department of Natural Resources (WDNR) has published its report, dated January 2012, on
Silica Sand Mining in Wisconsin. The report, in my opinion, presents a good summary of the mining procedures, the potential environmental impacts, and regulatory permitting framework in Wisconsin. The report mentions situations where the system falls short:
With the multitude of regulations the WDNR may have over a nonmetallic mine, it is important to note that there are times when permits are either not acquired prior to an activity taking place, or permit conditions are not being followed. The most common violations with regard to nonmetallic mining are a lack of attention to erosion control or storm water management, and not obtaining the proper permits for the operation. Permitting is sometimes neglected either because of a lack of information, or because of changing conditions in the mine.
Having worked as an environmental consultant on dozens of construction projects, both on the regulatory and development side, I’d agree that, often, erosion and sediment control are given a lot of “lip service,” but on-site enforcement is lax. It may be that soil and sediments are natural materials and it’s hard to think of them as pollutants. But, at times, they are.
Environmental due diligence on the developer’s part, and enforcement by the regulatory agencies are too often regarded as costly nuisances. Both project and agency managers are undoubtably pressured to cut any expense that doesn’t bring an accountable return on investment. The solution to the problem, like so many problems poorly understood, is sound science, education, and keep hammering the message home.