It is the source of the 300-million-year-old stones that define Main Line houses, and the epicenter of concussive explosions that were said to rattle the china at the Llanerch Diner.

In its time, it has ingested chunks of Philadelphia, massive quantities of Blue Route dirt, at least one car, and an airplane.

In short, the old Llanerch Quarry, near one of the region's most densely developed corridors in Haverford Township, Delaware County, was no ordinary hole in the ground.

Now, after years of acrimony, litigation, and frustration, its owners, the township, and the local school district hope it is about to become a gold mine.

Eureka Ventures, an Indiana-based developer, plans to transform the unsightly 31-acre site into a $35 million shopping complex called Quarry Center.

Eureka predicts that it will generate $700,000 in property taxes - a sixfold increase over what it produces now in a town with a stagnant tax base - and more than $7 million in sales taxes from tenants that include Giant and Lowe's.

"It's been a long haul," said David F. Crockett Jr., whose family has owned the troubled and storied property for more than 30 years.

"It's pretty amazing," said William Wechsler, 59, a township commissioner who grew up in the area and learned to scuba dive in the quarry after it had filled with water. "It's been a hole in the ground since I was a kid."

Officially, ground was broken 10 days ago. In reality, it has been smashed, shoveled, and scooped for the last year to prepare a site that once bottomed out at 50 feet below sea level. In all, 6.5 million cubic yards of material went into the cavernous quarry, which encompassed 26 acres - or 1.13 million square feet - and was 270 feet deep, Crockett said.

Last week, the site swarmed with yellow bulldozers, compactors, graders, and conveyors operated by the IMC Construction Co. Crews are using a 16-ton tamping device, which looks like a colossal rusted septic tank, to compact a generation of fill. "Don't let it fall on your foot," said Ken Umstead, the site superintendent.

Progress will come at a price. When the center opens later in the year, more traffic is a certainty in an already deeply congested area. Nearby residents have fretted over the coming vehicle crush and the prospect of harsh shopping-center lights invading their bedroom windows.

"I think you'd have to live in a cave if you didn't realize it was going to cause traffic congestion," said Thomas Wagner, a councilman in neighboring Upper Darby Township, who says his Drexel Hill home probably was built with Llanerch Quarry stone.

The site is on Township Line Road near its chaotic, angled intersection with West Chester Pike. Wagner said the developers eased some concerns by agreeing to a Route 3 connector at the rear of the complex. He said they also had toned down the lighting plan.

Neighbors have had a long and often contentious relationship with the geologically significant site.

The Philadelphia region has a particular abundance of gneiss rocks, said George H. Myer, geology professor at Temple University. The gneiss had been there for hundreds of millions of years - and then along came humanity.

The stones were plentiful in Llanerch, which also had a reservoir of the more glittery Wissahickon schist. The rocks were coveted by builders.

The company that operated the Llanerch Quarry dates to the early 20th century, according to the Haverford Township Historical Society, and many of the town's homes were built with Llanerch stones.

Loosening the material required extensive blasting, and old-timers recall the explosions' rattling the dishes and cups at the Llanerch Diner at its former location on West Chester Pike, said the society's Mary Courtney. "My mother said, 'Hold your ears,' " Wechsler said.

Flooding rains in the summer of 1973 - close to five inches fell June 29, one of the rainiest days in the region's history - inundated the quarry. Part of a wall collapsed, and wayward Naylor's Run Creek swamped the basin with 30 to 60 feet of water. The quarry shut down the following November.

The Crockett family eventually purchased the site and operated it as a clean-fill dump - dirt, rock, bricks, and the like - until two years ago.

The site has been the subject of numerous lawsuits and misadventures. Vandals once pushed a car into the landfill, a plane crashed into it, and in 1992 seven families were forced to evacuate their homes when they were threatened by another wall collapse.

Neighbors have complained about increased flooding, and in 2001 the Pennsylvania Department of Environmental Protection cited the owners for violating the Clean Streams Act after tests showed that a sewage odor was emanating from the landfill.

If all goes well, all that will be a memory by Thanksgiving, Crockett said. Weather and asphalt schedule permitting, the complex will open in November, he said.

"It's what I would call an infill redevelopment," said Eric Mallory, principal in Eureka Ventures. The stone-quarry business has remained stable, said Mike Loflin of the Marble Institute of America, with about 235 sites nationwide. Retired quarries have been put to a variety of uses, from parks to office parks, said Peggy Disney, his counterpart at the National Stone, Sand, and Gravel Association.

Mallory said Llanerch was ideal for a shopping center. "The demographics are phenomenal," he said.

If Mallory's projections are correct, Quarry Center will become one of the region's larger ratables. In 2010, the last year for which state data are available, no Haverford property sold for more than $2 million, and the township's total assessed value, $2.9 billion, was virtually unchanged from 2008.

The 14 parcels that constitute the site now yield about $76,000 annually to the schools, according to business manager Rick Henderson.

Mallory's estimates would mean more than $475,000 to the school system's annual budget.

Said Henderson: "Let's hope."

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