Blasting and Flyrock
This page deals with an aspect of blasting associated with quarries: flyrock.
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Flyrock
The Pennsylvania Bulletin defines 'Flyrock'' as any material ejected from the blast site due to the force of the explosion.
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Douglas Rudenko, VP for Vibra Tech Engineering, an expert witness for Gibraltar Rock, said in testimony that pieces of rock, the size of a softball, has been known to fly out of a quarry site---up to 1000 feet. The homes across Church Road and Hoffmansville Road are well within 1000 feet. Perkiomenville Academy is about 1050 feet from the proposed quarry. School busses pass well within 1000 feet of the proposed quarry.
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The picture above shows damage from airborn rocks from the Jefferson quarry in Mankato, MN.
As reported in the the Mankato Free Press, "A quarry that was accused in April 2017 of causing an earthquake-like tremor felt across a broad swath of Mankato has had its explosives license suspended after a blast that sent rocks larger than bowling balls soaring into a nearby neighborhood.
This picture is from a DEP slide presentation entitled, "The Adverse Effects of Blasting."
The large piece of flyrock is in the lower right of the picture.
The picture below, reported by Department of Labor's Mine Safety and Health Administration is from an accident report from Lancaster, PA. The driver of this truck was killed by flyrock The man was hit with a baseball size piece of flyrock that came through his truck's front windshield.
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The accident occurred on a roadway that was approximately 180 feet away from the west quarry wall, and approximately 800 feet from the blast holes. The report also mentions that "flyrock damaged a building approximately 1,500 feet west of this blast".
