Burnett County (WQOW) - The spill at a frac sand mine originated from a settling pond that was built in April.
It happened at the Tiller Corporation mine near Grantsburg in Burnett County. Late last month, a hiker reported seeing cream-colored water in a creek flowing to the St. Croix River. The DNR started investigating and says it came from a leak in a holding pond. An unknown amount of sand and other sediment ended up in a wetland that eventually flows into the St. Croix. The DNR says it's too soon to know how much damage was done.
A spokesperson for Tiller Corporation says there were no chemicals involved in the process.
Interstate Energy Partners, LLC (IEP) is the owner of a 72 acre sand and gravel mining facility (Facility) in Grantsburg Township. The facility owners obtained Conditional Use Permit #1310 (CUP) from Burnett County for the operation which was opened during the summer of 2011. IEP obtained WPDES Non-Metalic Mineral Mining General Permit 0046515-5 coverage per notice dated May 13, 2011. Tiller Corporation (Tiller), the operator of the Facility, is listed as the contact person and completes the necessary reporting. WDNR Regulations for the WPDES program prescribe that berms or dikes must be maintained to prevent discharge of waste water or stormwater. Accordingly the Facility has been duly authorized to operate under state and county authority.
The Facility includes multiple settling ponds used in the washing operations. An additional settling pond, Pond 10, was constructed during April, 2012 using local materials and following internal design. The materials used in the berm were granular in nature. Burnett County Land and Conservation staff and a WDNR Conservation Warden visited the Facility on April 26, 2012. Apparently the public observed turbid water in a stream flowing to the St Croix River and reported this to authorities on April 22, 2012. After inspection, it was determined that the material used to construct Pond 10 lacked sufficient clay or plastic characteristics needed to retain the ultra-small fines suspended in the wash water. Consequentially Pond 10 leaked carrying with it suspended fines. Upon realizing the situation, utilization of Pond 10 was voluntarily suspended pending reconstruction and inspection by Burnett County and WDNR. The process water remaining in Pond 10 was pumped to Pond 2.
The release from Pond 10 flowed east through drainage ditches created from past activities not associated with the current mining operation. The release eventually flowed south and southwest through a wetland classified by WDNR as: Forested, Scrub/shrub; Scrub/shrub; and Scrub/shrub, Emergent/wet meadow. The wetland is partially located on the Facility property. This wetland forms a creek that flows through a culvert beneath Highway 70 and ultimately flows to the St. Croix River.
Water containing suspended fines was observed in the wetland and creek and according to WDNR and Burnett County Staff water containing suspended fines was also observed at the confluence of the stream and the St. Croix River. During a site visit on May 1, 2012 which included WDNR and Burnett County staff, Tiller suggested two options for removing any remaining suspended fines in the wetland. One option was utilizing the flocculent Chitosan to precipitate out residual fines. The other option was to remove the water containing the fines by pumping it to containment areas within the Facility. The WDNR staff indicated that these activities were likely not necessary and responded by email on May 2, 2012 "…the general consensus was that nature is taking care of the problem by itself.". On May 2, 2012 Tiller contacted the U.S. Army Corps of Engineers to advise of the release to the wetland and on May 4, 2012 Burnett County Zoning and Land Use was contacted.
Turbidity sampling began on April 27, 2012. Sampling of Pond 10 shows turbidity of 831 NTU.
The first sample upstream of the HWY 70 Culvert indicated the highest readings of 52.3 NTU.
At the north end of the Facility turbidity readings in the wetland are 4-6 NTU. This appears to
be the background turbidity. On May 11, 2012 turbidity readings at the Hwy 70 Culvert are
6.24. This supports a conclusion that the current readings at the Hwy 70 Culvert are background levels.
During the week of April 30, Pond 10 was reconstructed. The berms were constructed using
materials containing sufficient clay or plastic characteristics needed to retain the ultra-small fines suspended in the wash water. Staff from WDNR and Burnett County inspected the reconstructed Pond 10 on May 7, 2012. Staff and Tiller agreed the reconstruction was sufficient to allow resuming the use of Pond 10. Performances of the berms are being confirmed by visual inspections and water quality monitoring.
Interstate Energy Partners, LLC
Grantsburg Wisconsin Facility
Tiller Corporation Operator
ST. PAUL, Minn. (AP) -- A spill at a sand mining facility in Wisconsin has dumped an unknown amount of sand and other sediment into the St. Croix River and wetlands near the Minnesota border.
Wisconsin DNR officials tell Minnesota Public Radio News (http://bit.ly/KvwIzH ) it's too soon to know how much damage was done.
Conservation officials learned of the leak on April 22, when a hiker reported seeing cream-colored water in a creek flowing to the St. Croix River. DNR investigators traced the murky water back to a sand mining facility operated by Maple Grove-based Tiller Corp., where they located a leak in a holding pond.
The sand is mined for use by the petroleum industry to help extract underground natural gas and oil supplies in a controversial practice called hydraulic fracturing, or fracking.
Information from: Minnesota Public Radio News, http://www.mpr.org