Ringwood continues sinkhole testing
Wednesday, July 4, 2007

By JAN BARRY
STAFF WRITER

RINGWOOD -- Experts plan to measure gravity to see what's under a former mining community beset by sinkholes.

Borough officials hired a geophysics company to operate a gravimeter, which records local variations in the Earth's gravity field, to determine if hidden voids lurk underneath homes on three streets in the Upper Ringwood neighborhood.

Two homes were evacuated last fall after sinkholes were found nearby. A street that is the only access for four homes was undermined by another set of sinkholes earlier last year, forcing expensive repairs.

If work can get started soon, results of the gravity tests will be available in a few weeks, Gary Gartenberg, a mining engineer hired by the borough, told a group of homeowners Tuesday. The borough is negotiating access agreements for the testing to be done on about a dozen residential properties.

Complicating the process, residents are worried whether Ford Motor Co.'s excavation work with heavy equipment in adjacent industrial waste dumps could have caused the sinkholes. Ford and the federal Environmental Protection Agency, which is overseeing a Superfund cleanup of toxic paint sludge, maintain that vibration tests done by Ford consultants found no relationship.

On Tuesday, residents of Van Dunk Lane peppered Gartenberg, other experts and borough officials with questions during an informal walk around the neighborhood. An additional concern was whether the sounds and vibrations from testing with drilling rigs, which was done to investigate sinkholes last year, could have aggravated health problems.

"When they did the drilling [last year], my husband had three strokes and an aneurysm," said Janice Morgan. "So I'm concerned. As long as there're no vibrations or noise, I won't have a problem."

Morgan's home is on a rock outcropping across Van Dunk Lane from the two houses that Ringwood evacuated last year when sinkholes were found next to the foundations. These homes and several others in the area were built in the 1970s on land reclaimed from iron mining operations that ended around World War II.

Richard Lee, whose Quantum Geophysics company will do the gravity testing, said the backyard grill-size device doesn't make vibrations. The computerized measuring device generates a color-coded contour map showing various underground features, he said.

Richard Volkert, a geologist with the state Geological Survey, said this type of testing is needed "to determine if the homes are habitable." Volkert said abandoned mines are "a pervasive problem across the Highlands," wherever homes are built over old mine shafts that in many cases were poorly mapped.

Adding to the residents' concerns, state and federal officials have been disputing whether Ford should stop its work with heavy equipment until the sinkhole investigation is completed.

On Tuesday, an EPA spokeswoman said Ford will not do any excavation work in the area where sinkholes were found near homes until both DEP and EPA staff approve a work plan that includes additional vibration testing that Ford is to do.

Staff Writer Barbara Williams contributed to this article. E-mail: barry@northjersey.com

Reprinted with permission from The Record

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