Rural Wisconsin is a mix of woods and water, farmscape and small towns--a landscape that is central to why so many choose to live here.

Frac sand mining is changing the face of this landscape physically, economically, politically and permanently.

You cannot have a discussion about frac sand mining without first talking about the increasingly important topic of home grown energy and, more specifically, the method of obtaining natural gas and oil from layers of shale found deep beneath the earth's crust known as hydraulic fracturing or "fracing."

Fracing has been around since the 1930s, but did not become economically viable until the 1980s, when the Energy Act of 1980 offered tax incentives for private research and development. That led to rapid improvements in the technology of horizontal drilling.

The process

Fracing involves the use of a drill pipe and bit to drill hundreds or thousands of feet through the aquifer (the underground water-bearing layer) into the layer of shale harboring the natural gas or oil.

After reaching the shale, fracturing fluid, consisting mostly of water and frac sand, is pumped under high pressure into the shale opening tiny fractures in the shale. Eventually, oil and gas flow back into the well and to the surface.

The geologic shale rock formations containing natural gas are called plays.

The five largest shale plays are Marcellus Shale located in Pennsylvania, Ohio, New York and West Virginia; Haynesville Shale located in parts of Louisiana, Texas and Arkansas; Fayetteville Shale located in Arkansas; Woodford Shale located in Oklahoma; and Barnett Shale located in Texas.

For more please read the Oct. 31 print version of the Herald.