What’s the difference between silica sand mining and fracking?
The dawn of silica sand mining at the limestone quarry and gravel pit on 267th Street, which came after the transition of ownership from Rybak to North 40 Resources in early 2019, has been the subject of much contention in recent months, drawing full houses at local town board meetings and inspiring citizen activism from opponents concerned about potential economic and environmental drawbacks.
Silica sand is colloquially referred to as “frac sand” when it is mined for the purpose of hydraulic fracturing, commonly called “fracking,” but what is the difference between the procedures, and how do they connect?
This article will compare and contrast the two activities on a process level, and is not intended to explore the pros or cons of either from an opinion standpoint.
Hydraulic fracturing (“fracking”)
When rock formations like shale posses rich quantities of resources like gas or oil, but cannot naturally release these materials into a well due to small or interconnected pores, fracking can prove feasible.
Widespread especially in the Western United States, the process begins with drilling a “well” into the rock, into which “frac fluid” — water, chemicals and silica sand — are forced through at high pressure powered by water.
The mixture eventually fractures the shale.
Although the frac fluid’s liquid components are released from these cracks, the solid sand remains, acting as a “proppant.” Without it, the fractures would close back up and the resources, i.e. oil, within would remain inaccessible. Silica sand prevents the fractures from closing, allowing the desired resources to leak out.
Silica sand (“frac sand”) mining
While Wisconsin is not a hotbed for fracking itself, its western half is arguably one of the nation’s more plentiful regions of the silica sand necessary for the activity. In the United States, this high grade of sand can only be found in the Midwestern Great Lakes region. It is composed of tiny pieces of the quartz found within sandstone, and blasting may be necessary in order to extract it depending on its density within the larger rock.
In order for silica sand to be mined, the designated area must be cleared of vegetation and topsoil. When topsoil, or “overburden,” is removed, the excess material is shaped into mounds known as “berms,” which help to shield the surrounding area from the mine’s light and noise.
After excavation, the sand will be washed, dried and screened to ensure that it is of the proper quality necessary for fracking. Washing involves chemicals that can leak into the ground, while the drying process is fueled by natural gas or combustion.
Potential air pollutants from silica sand mining include airborne crystalline silica and “fine particles” of sand (less than 2.5 microns), both of which have associated health risks.
What’s the next step for the Osceola area?
The issue will again arise at Farmington’s next town board meeting, which takes place on Monday, Aug. 5, at the town hall at 5:30 p.m. The meeting’s start time was moved back 90 minutes from the standard 7:00, in order to accommodate more community discussion and participation regarding the mine and the possibility of its further regulation.