Engineer notes 'fugitive dusts' as rock plant concern



By Lew K. Cohn

Managing Editor

The Highlander

A former Marble Falls mine safety engineer has warned members of a group fighting a proposed rock crushing plant of the dangers of “fugitive dusts” that will escape the facility if an air quality permit is approved by the Texas Commission on Environmental Quality, stating the plant should have been required to perform “air dispersion modeling” due to the proximity of Baylor Scott & White Marble Falls hospital.

Michael Clark also said noise and traffic can be expected to have an impact on the area where Asphalt Inc. wants to build its rock crushing plant and quarry south of Marble Falls near the intersection of US 281 and Texas 71.

Asphalt Inc. applied for an air permit from the Texas Commission on Environmental Quality (TCEQ) to operate a new rock and concrete crushing plant and quarrying operation with an entrance 90 feet west of US 281 and approximately 2.6 miles south of the intersection of Texas 71 near Flat Rock Road, which is Burnet County Road 403.

Concerned parties have until Oct. 9 to submit comments, questions and concerns to TCEQ in hopes of convincing the agency to hold a contested case hearing on the permit request. Written public comments about the application may be submitted to: Texas Commission on Environmental Quality, Office of the Chief Clerk, MC-1-5, P.O. Box 13087, Austin, TX 78711-3087, or electronically at

The rock crusher air quality permit ID number is 148112, while the registry number is RN109902312. As of Thursday, Oct. 5, there had been 65 requests for a public meeting and 505 written comments protesting the proposed plant.

At the request of state Rep. Terry Wilson, R-Marble Falls, TCEQ executive director Richard A. Hyde P.E. has approved a public meeting to be held in Marble Falls, but one has not been scheduled yet, according to the TCEQ website.

Clark was the regional environmental health and safety manager for J.M. Huber Corporation in Marble Falls from May 2006 through October 2011. Prior to that, he was a quality and environmental manager for Huber, where he was responsible for managing environmental air and water compliance programs and coordinating site regulatory permitting.

Currently, Clark owns his own business, S-E-Q Sustainability Systems, which performs Occupational Safety and Health Administration-based safety training as well as environmental and quality program development and auditing.

“(There will be an) increase in fugitive dusts due to mining and crushing activities,” Clark wrote in an email last month to Pat Dickey, a member of the coalition fighting the proposed plant. “Activities that will increase fugitive dusts are blasting; vehicles on haul roads; maintaining rock stock piles (loaders piling gravel onto and taking gravel from); wind blowing across surfaces that used to be covered with vegetation such as haul roads, travel roads, open ground (benches) in the mine; crushing operations.

“The mine should have control measures in place for these activities, such as applying water (possibly with dust-suppression additives) to haul roads and baghouses for crushing operations. In spite of control measures, there will be an amount of fugitive dust generated that escapes due to lack of perfect efficiencies of control measures, periodic failure of control measures.

“In order to secure the permit, the mining should have completed air dispersion modeling due to concerns over fugitive dusts,” Clark added. “The modeling should have been required especially given proximity to the medical facility. Verify modeling parameters and extent of dust plumes. Concerns can be raised over the impacts of fugitive dusts on the health of neighbors and especially the medical facility.”

Clark said fugitive dust from the plant will primarily be calcium carbonate (limestone), which is “classified as a nuisance dust but does have a threshold limit value for health exposure purposes.”More of concern, however, is a smaller amount (5 percent) that will be crystalline silica, which he said “is classified as a known carcinogenic material and has a lower threshold limit value than the calcium carbonate.”

Clark told Dickey increased noise in the area “will have an environmental effect that increases above background such that neighbors will know the mine in present.

“Background noise will change to include mechanical sounds (crushers, conveyor belts, front-end loaders, dozers, haul trucks) above what had been peaceful country sounds,” he wrote. “Traffic will increase due to OTR (over-the-road) trucks entering and exiting the highway, workers coming and going.”

Clark said he did not think blasting and open-pit operations were as likely to affect groundwater in the area, however.

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