Expert testifies that damage would be contained inside the property line

        A blasting expert testified that the detonation of explosives at the proposed Gibraltar Rock quarry would not fracture any underground rocks beyond the property line.

        Vice president and northeast regional manager for GeoSonics/Vibra-Tech, Douglas Rudenko, also stated that students at the New Hanover Upper Frederick Elementary School, just 3,000 feet away from the proposed quarry, might experience the blasts.

        GeoSonics/Vibra-Tech is a Pennsylvania company that evaluates critical mining operational issues.

        "It's possible that the students and teachers would feel the ground shake," Rudenko said on Thursday, June 2 during the monthly Gibraltar Rock IV zoning hearing in New Hanover.

        The Silvi Group, a Bucks County concrete business, seeks a special exception to the municipality's zoning use regulation to quarry an 82-acre parcel north of Hoffmansville Road.

        The company has already received approval from the board to mine 163 acres between Church Road, Route 663 and Route 73. The application requires land development approval from the township's board of supervisors.

        Municipal officials and residents have expressed concerns that the quarry operation could disrupt a plume on the former Good Oil property, located north of Hoffmansville Road, and contaminate the local watershed and private wells.

        Stephen Harris, the lawyer for the applicant, rested his client's case after 11 sessions.

        According to Edward Skypala, the zoning hearing board solicitor, lawyers representing the township and Paradise Watchdogs/Ban the Quarry will have the opportunity rebut evidence presented by the applicant or introduce new evidence by calling witnesses and introducing exhibits.

        Facing redirect and cross examination, Rudenko detailed the process by which the applicant would utilize explosives to mine for diabase, argillite and hornsfeld.

        He said the applicant submitted a blast plan to the Pennsylvania Department of Environmental Protection that calls for detonation materials to be stacked in bore holes not to exceed 6.75 inches in diameter. Rudenko identified the blast radius for each hole as approximately 16 feet.

        The witness stated that the blasting would have no affect at all on the plume of contaminants, which includes 1,4 dioxane, Methyl Tertiary Butyl Ether (MTBE) – a chemical compound used as a fuel additive – and other volatile chemicals, located on the former Good Oil property north of Hoffmansville Road.

        "There won't be enough energy to alter those materials," Rudenko said during the hearing.

        State regulations limit the rate of the explosions at two inches per second, according to the witness. He said five inches per second would be the necessary rate to worsen existing cracks, let alone create new ones.

        Under cross examination from Rowan Keenan, the lawyer representing Ban the Quarry, the witness confirmed that extensive ground vibrations could expand existing fracturing outside the fracture zone.

        Responding to a question by Wendy McKenna, an attorney representing the township, Rudenko said he has seen the damage to homes, which includes cracks in the plaster and window damage, caused by the human error of irresponsible blasting.

        "This sort of damage is rare, but possible," Rudenko said.

        The hearing is scheduled to resume Thursday, July 7.