A licensed geologist testified last week that a proposal by the Silvi Group to quarry an 82-acre parcel in New Hanover Township would allow an underground plume of volatile chemicals to reach areas currently not contaminated.

                Gilbert Marshall, of Marshall Geo-Science in Collegeville, told the township's zoning hearing board, under oath, that the mining and dewatering of the property north of Hoffmansville Road would draw the plum which is currently located underneath adjacent properties into the pit of the proposed quarry.

                The Silvi Group's Gibraltar Rock, Inc., a Bucks County concrete business, seeks a special exception to the municipality's zoning use regulation to quarry on the parcel.

                The company has already been granted a special exception 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.

                At a July 7 zoning hearing, Marshall discussed findings from a report he conducted for quarry opposition group Paradise Watchdogs/Ban the Quarry that warned of the potentially dire consequences.

                According to Marshall's report, Gibraltar Rock "has not established appropriate detection, monitoring or remediation systems to properly identify, characterize and remediate contaminated ground water that will be captured by the proposed quarry operations."

                Marshall said the chemical plume, located below the former Swann Oil/Ethan Good site on Route 663 north of Hoffmansville Road and the Hoff VC Superfund site on Layfield Road, is "approximately 300-feet deep, 75 acres in size and ½ acre across." It contains three known human carcinogens and multiple other chemicals that are probably or likely carcinogens, according to the report.

                Under questioning by Rowan Keenan, an attorney for Paradise Watchdogs/Ban the Quarry, Marshall testified that one possible scenario of quarrying in the region could include the migration of the contaminated water towards the area of sump pumps located on the quarry property.

                Marshall's report concludes that if the volatile chemicals are not properly remediated, "the extensive and recalcitrant ground water contamination will present a significant long-term threat to human health and that the environment that is not limited solely to the operational life of the quarry, but will persist after quarry operations are terminated and the open quarry pits are flooded with contaminated ground water."

                According to the hydrogeologist, the only way to prevent the plume from shifting, other than total remediation, is to avoid quarrying in the vicinity.

                Edward Skypala, the zoning hearing board's solicitor, adjourned the meeting after an hour of testimony. Stephen Harris, the attorney for the Gibraltar Rock IV application, told the board he would need to study Marshall's report before mounting a cross-examination.

                The hearing is scheduled to resume at  6:30 p.m. on Thursday, Aug. 4.