FALLBROOK -- Business and community leaders gathered Thursday to talk about the effect the proposed Liberty quarry pit near Fallbrook would have on the town.

The presentation included information that has been reviewed at other meetings over the last three years, such as concerns about air pollution, property values and how the proposed quarry would affect the environment.

Granite Construction, which proposed the project in 2005 and is currently developing an environmental impact report for the 155-acre mine, has said it will be far enough away from Fallbrook that it will not affect any of those factors for those who live here.

But some of the 30 leaders who attended the Fallbrook Revitalization Council meeting said the location isn't right for a mining operation.

"We all know the importance of having materials that come from a quarry," said Jim Mitchell, a Temecula resident who led the presentation as a member of the opposition group Save Our Southwest Hills.

"But the location they have chosen is just unbelievable. What we've got here is a problem with location -- not a problem with the quarry, as such. This is something that our grandchildren would be living with, as well."

The quarry would be on a 414-acre site in Riverside County just north of the San Diego County line and west of Interstate 15 -- about seven miles northeast of downtown Fallbrook.

Granite Construction officials have said that Liberty quarry would operate for at least 50 years, and they have described it as an unobtrusive operation that is necessary because of the demand for construction materials.

"All of the technical reports on air, light, noise and vibration indicate that there (would be) no significant impact even at our property lines for the project," said Gary Johnson, a project manager with the mining company. "All those levels are under the standards at the property line, so five miles away in Fallbrook, they won't even know it's there."

Vince Ross, president of the Village Association and a proponent of enhancing downtown Fallbrook as a ritzy tourist destination, said he is worried about the negative perception that may come with a rock quarry nearby.

"We have often been described as a little oasis in a sea of sprawl," Ross said after Thursday's meeting. "Our quality of life is still nicely protected, so I don't see why we can't find a way to prevent it from being threatened. I think our town needs to stand up on these kinds of issues. We know it's going to be a continual battle for us to keep it this way."

Ross also serves on the board of directors for the Fallbrook Land Conservancy, which has opposed the quarry because of its potential impact on the region's ecosystem.

One concern discussed Thursday was how the quarry could harm sensitive biological research conducted throughout the year at San Diego State University's Santa Margarita Ecological Reserve, which borders the quarry site.

"On our northern boundary, we have a beautiful space along the Santa Margarita River," Ross said. "It's used recreationally by hikers and equestrians, and it's destined to be permanent open space."

He said it's important to maintain that strip of pristine habitat, adding he's concerned that Granite Construction's proposal would degrade land that the university has managed to keep in pristine condition for decades.

Representatives of the mining company have repeatedly stated that they will do everything possible to prevent the quarry from affecting the reserve or the research conducted there.

Contact staff writer Tom Pfingsten at (760) 740-3516 or tpfingsten@nctimes.com.