Tiller Corporation penalized for air-quality violations

Contact: Ralph Pribble, 651-757-2657

St. Paul, Minn.— The Minnesota Pollution Control Agency (MPCA) has penalized the Tiller Corporation, which operates a processing and shipment center for silica sand in North Branch, Minn. for multiple violations of the facility’s air quality permit.

The company built the facility in 2012-13 and began operating following issuance of an air quality permit from the MPCA in January 2013. Silica sand is brought to the facility from mines Tiller operates in Wisconsin, and processed for use in hydraulic fracturing and other industries. The product is shipped by rail and truck from the facility.

The permit requires performance tests of control equipment to ensure the facility’s emissions meet applicable air quality standards. The company is required to submit the results of these tests to the MPCA.

Test results were submitted to the MPCA in October 2013, covering testing performed in the summer of 2013. The results showed the facility exceeded many of its permitted emission limits for particulate matter, carbon monoxide, volatile organic compounds, and sulfur dioxide on emission sources at the facility. A separate report submitted to the agency also showed that nighttime noise limits were exceeded at two fence-line monitoring locations. Other testing during November 2013 indicated continued noncompliance with carbon monoxide and volatile organic compound emission limits. Additionally, the MPCA found that testing frequency plans, required following initial testing, had not been submitted. In all there were 45 missing submittals, 25 emissions violations and four noise violations.

To resolve the violations, Tiller agreed to pay a civil penalty of $85,000 to the state. In addition, the company agreed to modify certain emissions control equipment and complete modifications to mitigate noise within 90 days. When those measures are complete, the company will conduct noise monitoring and submit results to the MPCA.

When calculating penalties, the MPCA takes into account how seriously the violation affected the environment, whether it is a first-time or repeat violation, and how promptly the violation was reported to appropriate authorities. It also attempts to recover the calculated economic benefit gained by failure to comply with environmental laws in a timely manner.

For a comprehensive list of enforcement actions by the MPCA, refer to the agency website at www.pca.state.mn.us.