Vulcan Materials Co., the largest producer of crushed stone in the nation, wants to quarry rock from 1,200 acres it controls near Gainesville, in the heart of Prince William County's industrial region.

County officials, though reluctant to see the prime industrial land used for a quarry, appear receptive to Vulcan's rezoning application because the site lies within an area that now is little used and is planned for heavy industrial use. Vulcan's land lies about one mile southeast of Gainesville between Wellington and Linton Hall roads.

But some nearby residents and land brokers fear that the noise, dirt and dust from a quarry would mar the image of the area just when Prince William officials are trying to promote the Gainesville area as a home to the white-collar, high-technology world.

"Any more real heavy industry could be detrimental to the trend [toward high-technology businesses] we are seeing," said Sue Coe, a real estate broker with Mount Vernon Realty.

Prince William County's image took a turn for the better this past summer when widely acclaimed golf course architect Robert Trent Jones Sr. announced plans to build championship golf courses and an office park near Gainesville. Two weeks ago, Centennial Development Corp. said it also plans a corporate office park adjacent to the Manassas National Battlefield Park. Both sites are less than two miles from the proposed quarry.

Such developments signal that the urban core of Manassas is moving westward, making a rock quarry with a 50-year lifespan the wrong land use, said Virginia Heal, who lives on Jennell Drive in a subdivision west of Manassas overlooking the eastern edge of Vulcan's land.

"I think the quarry would be in the wrong spot. . . there will be too much dust in the air. The roads are not ready; they are inadequate for today's traffic," Heal said. Vulcan officials, well aware that quarries are rarely neighbors of choice, are taking pains to address these concerns.

To help protect adjacent propperty owners, Vulcan has applied to the county for permission to quarry the hard diabase rock from only 540 acres, less than half of the land it controls, leaving plenty of surrounding property to buffer the quarry from neighbors.

In addition, Vulcan has promised to build 20-foot-high earthen barriers to help hide unsightly piles of stone and crushing equipment from view and to install elaborate water-spraying systems to dampen dust that might blow from the 80-foot-high mounds of crushed stone. The water system also would wash down trucks before they leave the site.

Vulcan has offered to hire an independent hydrologist to monitor nine test wells around the quarry site to ensure that quarrying does not disturb local water supplies. John E. Graham, Vulcan's regional manager, also said his company will hire seismological engineers to investigate the possibility that shock waves set off by explosives used to blast out the exceptionally resilient rock might upset sensitive scientific equipment used by surrounding high-technology businesses.

As part of its effort to woo local support for its project, Vulcan last week hired a helicopter for an afternoon to ferry politicians, the public and the press over the site.

As the chopper hovered over acre after acre of dense woodland, Vulcan's attorney, Michael Giguere, pointed out the isolation of the spot.

Supervisor Joseph D. Reading, who represents the Manassas area, where Vulcan already operates a quarry next door to a high school and town-house development and a short distance from an IBM plant, said so far he is favorably impressed with the application.

"They have been one of the most cooperative industries in Prince William County I have ever worked with. . . . I don't think anybody is going to know they are there," Reading said.

Dyan Lingle, the county's economic development officer, said a quarry is hardly the ideal use for the county's industrial heartland. But she said she doubts that it will hinder her efforts to promote the area. "We'll make the most of it. After all, we do need cement," Lingle said.

Vulcan officials said quarrying is one of the prices a region must pay for rapid urban growth. The hard rock is needed for road building and concrete mixers, but the high-bulk, low-cost item must be within 25 miles of its market to be economically quarried, Graham said. The Gainesville site is ideal because it is adjacent to Interstate 66 and has access to a rail line, making it easy to ship to the booming construction sites in Northern Virginia, he said.