Sand fracking is when sand is used as a proppant and blasted into a gas shale well to promote the production of gas. Sand is mixed with industrial fluids and water during hydraulic fracturing to force open underground cracks where natural gas is produced.
A special rock formation called the Marcellus shale contains natural gas. The shale is located a mile below the earth's surface. Sand, water and chemicals are injected into the rock formation under extremely high pressure, which forces natural gas to be released as the shale is fractured. Approximately, six million gallons of water are used in the fracking process. The water is piped from local streams and rivers. As of 2014, 56.3 billion pounds of sand are used annually in the sand-fracking process by energy companies. Sand helps to crack the rock, which causes the natural gas to flow into the wells.