Since the beginning of time, the human race has been taking what they need from the Earth in order to survive. Over time these needs have gotten more extensive. We now need to look for different options to provide for our greedy habits. The means to energy has gotten more slim with the development of motorized vehicles and other technologies. The relatively recent idea of hydraulic fracturing has been explored to provide a source of natural gas.
The process of hydraulic fracturing provides an innovative way to extract natural gas out of the ground. Shale is a type of rock that commonly holds natural gas. It forms in relatively thin sheet like layers but is good for containing natural gas due to its impermeability. This means fluids cannot pass through this layer in the ground. A small amount of explosives are used to crack open the shale rock. Sand is then placed into those cracks to keep the rock open long enough to extract the gas within it.
A process like this may seam rather simple, but a certain type of sand must be used in order for this to work properly. The sand grains must be about the same size, otherwise the opening in the rock will not be the same throughout the fracture. The sand grains must also be well rounded. If angular grains are sent into a fracture, the grains may be wedged in the opening at an obscure angle, which would also cause the opening to be irregular. Each sand grain must also have a relatively high strength to them. The shale rock that the sand is being sent to is relatively deep in the ground and feels a lot of pressure from the overlying rock. This high pressure could cause the opening to collapse if the sand grains are not strong enough to hold it open. On Moh's hardness scale, the mineral quartz is about a 7 (the highest value is 10). This mineral provides the strength needed to keep a fractured shale open. The Cambrian and Ordovician aged sand, most commonly from the Jordan Sandstone and the Mt. Simon Formation, found in western Wisconsin fulfills these criteria pretty well.
Even though hydraulic fracturing appears to be a solution towards our high need for energy, there are environmental impacts to consider. Any type of mining takes a toll on the air quality in surrounding areas. The chemicals used at a mine site may become airborne and blow to surrounding residential areas. The dust from blasting at a site may also get carried to residential areas. A fluid is used to help get the sand grains wedged into the cracks of the shale rock. People worry that this fluid gets into the ground water when sending it down into the ground and bringing it back up to the surface. Some people believe that this fluid affects their drinking water and that they may be ingesting chemicals from this process. This fracking fluid may also be harmful to the environment because of the chemicals that it contains. It is possible to have this fluid enter surface water in streams, rivers, or lakes. Heavy research is done to look for biodegradable chemicals to use. Great caution and intense reclamation is done as well to ensure safety for the environment.
Another issue is the affect that transportation of the sand has on the environment. Large trucks are needed to transport the sand from the mining site to the railroad where the sand is further transported. The roads that the trucks travel need to be replaced more often than normal roads due to the heavy loads that are transported along that route. This can get expensive for the state if many roads need replacing often.
GIS can be used to help solve some of these issues. Through this program, we can explore the areas subjected to environmental impacts, monitor how water flows in and around the mining site, and look at how the roads are affected by transportation.
I am a geology major at the University of Wisconsin-Eau Claire. Kent Syverson is the leading professor in the geology department who studies hydraulic fracturing and sand mining. My knowledge of the material comes from his various teachings.
