Sunrock quarry in air quality permit process


The proposed Carolina Sunrock quarry in Caswell County is in the midst of the North Carolina Division of Air Quality permitting process, pending clarifications from the company.

At 131 pages in length, including the eight appendices, the application outlines the quarry’s processes, equipment and potential emissions.

The quarry is located at 1238 Wrenn Road in Prospect Hill and has drawn criticism due to its proximity to Lake Roxboro. The permitting process will set limits on the amount of pollutants the facility can generate.

According to follow-up emails, DAQ received the application Nov. 18.

Dylan Wright, an environmental engineer with DAQ sent a 17-point response asking for more information Jan. 2 and according to emails between DAQ and Sunrock representatives, the two groups are working through the questions.

Included in the application are several limitations proposed by the company to reduce the potential emissions of particulate matter and carbon monoxide.

According to the U.S. Environmental Protection Agency, particulate matter is a mixture of solid particles and liquid droplets found in the air, including dust, dirt, soot, smoke and other particles invisible to the naked eye. Those particles can cause serious health problems if inhaled and are the main cause of decreased visibility and haze in parts of the country.

Sunrock requested restrictions on the production of the facility’s hot mix asphalt plant to 40 percent of the maximum annual operation – 876,000 tons per year of asphalt. Also included in the application was a request to cap quarry operations to a maximum of 4,745 hours per year – roughly 13 hours per day – which would yield 7.1 million tons of rock per year.

The third and final request is to limit operation of the facility’s three natural gas/propane-fired generators to only two simultaneously – a limit of 17,520 hours per year. However, this request drew questions from DAQ as to how the operation would be monitored with the possibility of an electronic system to prevent the third generator from turning on or keeping daily records of the generator start and end times. Scott Martino, Carolina Sunrock Environmental Compliance Manager, said Sunrock would like to stick with a limit of 17,520 hours per year and would have no problem tracking operating hours per unit daily or monthly. Martino clarified that the generators are computerized and only activated when needed by the electric demand of the facility and that one generator will serve as a backup if another is offline. Under the computerized system, it is possible to keep the third generator from being turned on with the other two running, Martino wrote.

DAQ questioned what the expected operating schedule would be. Sunrock said that actual hours of operation are to be determined, but are expected to be approximately six days per week and 12 hours per day – or 3,744 hours per year.

Also included in the DAQ response were questions on the levels of several emissions, but after some correspondence, it was discovered that the totals were correct.

According to the emission calculations, the entire facility would produce 174.74 tons per year of particulate matter, 30.37 tons per year of sulfur dioxide, 45.26 tons per year of nitrogen oxides, 99.56 tons per year of carbon monoxide and 43.98 tons per year of other volatile organic compounds.


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