The fracking methods that are deployed by the natural gas and oil explorers only involve two similar kinds. There is hydrofracking and propane fracking. Both use a similar slurry of frac sand and surfactant of about 0.5% of the overall components, but the main component is where the difference lies.
Hydrofracking involves the use of water as the main fluid source. This is a known substance that is non-toxic and non-hazardous to use and work with. This method involves a slurry mixture of 99.5% water and the remainder consisting of frac sand and surfactants. This slurry is pumped down into the borehole of the well at 100 barrels a minute, and the fracking pressure can be as high as 15,000 psi to crack the rock bed below. The fracking medium is recovered after the rock bed is cracked. The water returns to the surface and is held in a collection pond close to the borehole.
Propane fracking involves the same components but instead of water, a LPG in gel form is used. This, too, is non-hazardous and non-toxic while it is in gel form. Once it becomes a gas, there is a flammability issue that has to be addressed. The main difference is the way the medium is recovered. The LPG gel evaporates after the pressure is released, and the gas is contained in a tank instead of a pond.
This procedure has been used for over 60 years in the natural gas and oil exploration. What most people are unaware of is that it has other uses that have been deployed for the same amount of time. The most common is the use of fracking to stimulate a groundwater well. There has been some debate over the use of hydrofracking and what it is doing to the ground water, but they forget this is the method that is used to keep old water wells functioning.
Other uses include the use of fracking to help carve out mines, and for the tunnel construction for roads and railroads. This is a far safer method than with the use of dynamite.
The fracking methods that are being deployed today have many beneficial uses that include more than just extending the recovery efforts of the natural gas and oil wells.