Engineers, geologists and scientists clashed Monday during the Riverside County Planning Commission's meeting on Granite Construction's Liberty Quarry project, a mine proposed for land south of Temecula.
The session was the fourth in an ongoing series that has been followed by thousands of area residents.
In many cases, the testimony provided Monday by the various different subject authorities was contradictory ---- with one person saying everything has been studied according to the proper guidelines and another person contending that statement was false or misleading.
And there also were moments when someone defending their work was caught off guard by a speaker who brought new information to the forefront.
Commission Chairman John Roth summed up the process, which sparked multiple digressions by commission members on the wisdom of the format, as "dueling experts."
So who won the duel?
"It's up to the commission to sort through that and find out the correct answer," Roth said.
When that might be remains to be seen. The commission wrapped up Monday's meeting at 7:45 p.m. without reaching a decision.
Roth said there would be another meeting ---- the fifth in the series ---- on Aug. 15 at 9 a.m. in the same venue, the Rancho Community Church in Temecula.
Granite has proposed operating the mine within a 400-acre property that sits between the San Diego County line and Temecula's southern border. At full capacity, the 135-acre quarry is expected to generate 5 million tons of aggregate rock per year at the site.
After the Planning Commission is finished reviewing the project, the commission's recommendations will be sent to the county Board of Supervisors, which will have the final say.
One of the sharper exchanges Monday occurred after the lunch break when Matt Rahn, manager of San Diego State University's scientific field station located to the west of the quarry site, and Granite Project Manager Gary Johnson debated the effects vibration from blasting would have on animals in the area.
Johnson said he has not heard anyone affiliated with SDSU say exactly how much vibration is harmful to the area's wildlife.
Absent that, Johnson said, "I have a hard time believing anyone can credibly say it's going to harm biology or research" in the field station.
"Well, I just did," replied Rahn, who earlier had said that SDSU provided stacks of literature to the county about how various species are affected by increased levels of noise and light.
Before the lunch break, Johnson told Roth that the format of having speakers clash with the consultants providing rebuttal testimony was more than a little unusual.
At the previous meeting in June, Johnson and the consultants who worked on the environmental impact report took notes as speakers, the vast majority of them quarry critics, took their turns bashing both the project and the county's environmental report on it.
Granite officials said they had planned to provide a rebuttal to that information at Monday's hearing. And though that was accomplished in part, there was new information presented by critics who were being prompted by questions posed by the commissioners.
This put Granite in the position of rebutting a new slate of information, a stance that its legal counsel warned could create a "rebuttal loop" that would have no end.
The commission's counsel, however, said the commission members have the right to ask questions of anyone at any time and the commission proceeded for the entire meeting Monday following that direction.
Another topic that sparked a spirited debate during the meeting was air quality.
An engineer with Sage Environmental, Paul Weir, said the effects blasting at the mine would have on the area's air quality were vastly underestimated because the firm that worked on the study, Kleinfelder, used a formula suited for coal and not hard rock.
Coal is much more of a wet substance, making the use of that formula misleading, Weir said, adding that the actual effects on the area could be 250 times higher than the Kleinfelder findings.
Kleinfelder's air quality expert, Russ Erbes, said the claim made by Weir, if his argument was correct, wouldn't amount to any large difference in the findings because blasting accounts for a small amount of the total air pollution the project is expected to generate.
Weir disagreed, saying it could tip the scales and push the project's projected air pollution totals above the state's strict standards.
At the beginning of the hearing, Kleinfelder's geologists were put on the spot and forced to defend their findings that the project wouldn't sap the area surrounding the mine of life-sustaining water for vegetation or cause earthquakes.
An expert on earthquake faults said Kleinfelder did not investigate possible faults in the area and a geologist commissioned by the city said the methodology used by Kleinfelder was not extensive enough to determine how much water is stored in the mountain and how it moves.
The Kleinfelder representatives, Russ Keenan and James Finegan, defended their work, arguing that the methodology and findings were sound.
