REGION: More aggregate mines needed, report says

A truck dumps sand and aggregate into a crusher at Granite Construction's Indio quarry. A new state report concludes many regions in California lack enough aggregate - tiny rocks forming the base for construction materials - to satisfy future building demands.

California and parts of the Inland area need more aggregate mines to meet future demand and prevent higher construction costs and air pollution, according to a new state report.

The findings of the California Geological Survey report mirror arguments made by mine developer Granite Construction during its failed bid to build Liberty Quarry outside Temecula.

But quarry opponents and Temecula officials said fears of an aggregate shortage are overblown.

Aggregate is sand, gravel and crushed stone used in concrete and blacktop.

"While aggregate isn’t as glamorous as gold, it’s literally one of the cornerstones of modern society and important to the state’s economy," said State Geologist Dr. John Parrish in a news release from the California Department of Conservation, which oversees the survey.

Statewide, the aggregate and construction industry’s economic impact has been $230 billion and the industry supported more than 1.8 million jobs in recent years, according to the California Construction and Industrial Materials Association.

The report released Tuesday, March 5, analyzed 31 areas that cover about a third of California and provide aggregate for 85 percent of the state’s residents.

As of January 2011, 19 of those 31 areas had 50 percent or less of their projected, 50-year aggregate demand met by existing reserves, according to the report.

The area around the city of San Bernardino has enough legally mineable aggregate to last 11 to 20 years, according to the report. Temescal Valley and Orange County need 1.07 billion tons of aggregate in the next 50 years, but only 297 million tons are permitted for extraction, the report found.

Demand for aggregate is lower compared to previous studies because California’s population isn’t expected to grow as much, according to the report.

"The bottom line is, while we may need less building material than we anticipated a few years ago, we still need lots of it," Supervising Geologist John Clinkenbeard said in the release. "And there are parts of the state where they’re going to have to find new sources fairly soon."

Permitted aggregate reserves in western San Diego County, where most of Liberty Quarry’s aggregate was projected to go, are expected to run out in 10 years or less, the report found.

Without nearby mines, aggregate must be trucked in from long distances, boosting aggregate costs and leading to more traffic congestion, wear and tear on roads, air pollution from diesel fumes and greenhouse gas emissions, according to the report.

A disruption in aggregate supplies could hurt a construction industry still recovering from the Great Recession, said Brian Turmail, executive director of public affairs from the Associated General Contractors of America.

"The market is so fragile, you don’t want to be the straw that breaks the camel’s back and this has the potential to do it," he said.

In an email, Granite executive Gary Johnson said the report "confirms what most people knew, Western Riverside County and San Diego County do not have enough permitted aggregate sources to sustain our economy."

He noted the report’s conclusion was very similar to that of Liberty Quarry’s environmental impact report, which was paid for by Granite and vetted by Riverside County planners. A 7-year battle over the quarry ended last year after Granite agreed to sell the proposed quarry site to the Pechanga Band of Luiseño Indians.

The state Department of Conservation took no official stance on the quarry, which faced opposition from Temecula city leaders, the Pechanga tribe and local residents. Critics maintained the quarry would produce hazardous airborne silica dust, spoil a sensitive ecological reserve and wreck a thriving tourism industry.

Temecula Mayor Mike Naggar was skeptical of the latest state report on aggregate. Research done by the city found there’s plenty of aggregate to meet regional demand, he said.

Opponents also accused Granite of making up an aggregate crisis to justify the quarry.

In a February 2012 letter about the quarry to the Riverside County Board of Supervisors, then-Temecula City Manager Bob Johnson argued the formula used to determine future aggregate demand was flawed. The letter quoted a 1991 state report as saying the Temescal Valley area had 924 million tons of mineable aggregate.

After subtracting what was actually mined from the valley since 1991, 705 million tons of aggregate remains, enough to last 68 years, the letter read. That doesn’t include new mines or expansions of existing mines, the letter added.

Seventy-four billion tons of aggregate could potentially be mined in the 31 areas studied, but it’s unlikely all of that aggregate will be extracted, the state report found. "The location of aggregate resources too close to urban or environmentally sensitive areas can limit or prevent their development," the report read.

Right now, Riverside County is reviewing one application for a new mine and there are no pending mine applications in San Bernardino County. Riverside County has 53 permitted mines in unincorporated areas and 10 active sand and gravel mines are under San Bernardino County’s jurisdiction.

Granite is still looking to build a mine in the region, Johnson said.


Aggregate is a term used to describe types of sand, gravel or stone extracted from the earth and used as a base for concrete, asphalt and other construction materials.

Lots of rock: From 1981 to 2010, California used an average of 180 million tons of aggregate a year, according to the state Department of Conservation. Statewide demand for aggregate is expected to eclipse 12 billion tons over 50 years, based on department estimates.

Site design by Chris Kennedy. Content copyright Construction Industry Air Quality Coalition.

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