Deep Shallow
ORDOVICIAN
Sea Level Frac sands were rounded when above sea level!
Million Years old
Shoreline
Frac sands
CAMBRIAN
Rocks of the Kickapoo River watershed
Sand grains were rounded when they were above sea
level and blown about by the wind, forming sand dunes.
Each sand grain underwent this process many times.
Sand grains moving in water
are cushioned from each other
when they collide.
Windborne sand grains can
travel much faster, and can
collide unimpeded, thereby
rounding each other.
Which kind of sand makes the best aquifer?
Poorly sorted, angular
Well sorted, angular
Poorly sorted, rounded
The more pore space between grains
to hold water, the better.
Small grains occupy pores.
Angles and edges occupy pores.
Pore space is maximized between
rounded grains of the same size.
Well sorted and rounded
Nature expended huge amounts of time
and energy to make well rounded, well
sorted quartz sand grains.
The most important benefit to humanity:
Such deposits have been the best
groundwater aquifers for hundreds of
millions of years.
But the same properties also make the
sands the best and most abundant
“proppants” for fracking.
Frac sand mining
A single mine uses hundreds of thousands of gallons of water a
day. Two near Calico Rock, Arkansas use 678,000 gallons/day.
Issues: Surface water and/or groundwater depletion and
contamination.
The Wisconsin Geological and Natural History Survey and
Wisconsin Department of Natural Resources appear to be
proponents and apologists for frac-sand mining.
Historically, WDNR allows lobbyists for any industry to
write the regulations for that industry.
The following slides and slide portions with blue background
come from this presentation.