The Scandia City Council holds a special meeting Tuesday to decide whether a proposed gravel mine has received enough environmental study.
The mine would be about 30 miles northeast of St. Paul, on a bluff above the St. Croix River.
Jill Medland, with the National Park Service, said the environmental review is inadequate because it ignores noise standards designed for the National Scenic Riverway, and instead uses state standards.
"Those particular noise standards would allow for such an increase in noise levels on the riverway that two people canoeing side-by-side would not be able to carry on a conversation," Medland said. "We believe that clearly, such an increase in noise levels is not applicable to the riverway."
The environmental review said the mine would not have a discernible impact on local tourism because the noise would not exceed state standards, and local highways can handle the added traffic.